Enstar Group Limited (ESGR) 10-K 27 Feb 20 2019 FY Annual report Financial data

Cover page

Cover page - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Feb. 24, 2020	Jun. 30, 2019
Document Information [Line Items]
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Entity File Number	001-33289
Entity Registrant Name	Enstar Group LTD
Entity Incorporation, State or Country Code	D0
Entity Address, Address Line One	Windsor Place
Entity Address, Address Line Two	3rd Floor
Entity Address, Address Line Three	22 Queen Street
Entity Address, City or Town	Hamilton
Entity Address, Postal Zip Code	HM JX
Entity Address, Country	BM
City Area Code	441
Local Phone Number	292-3645
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Public Float			$ 1,860
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement to be filed with the Securities and Exchange Commission pursuant to Regulation 14A relating to its 2020 annual general meeting of shareholders are incorporated by reference in Part III of this Form 10-K.
Entity Central Index Key	0001363829
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false
Document Annual Report	true
Document Transition Report	false
Ordinary Shares
Document Information [Line Items]
Title of 12(b) Security	Ordinary shares, par value $1.00 per share
Trading Symbol	ESGR
Security Exchange Name	NASDAQ
Series D Preferred Shares
Document Information [Line Items]
Title of 12(b) Security	Depositary Shares, Each Representing a 1/1,000th Interest in a 7.00%
Trading Symbol	ESGRP
Security Exchange Name	NASDAQ
Series E Preferred Shares
Document Information [Line Items]
Title of 12(b) Security	Depositary Shares, Each Representing a 1/1,000th Interest in a 7.00%
Trading Symbol	ESGRO
Security Exchange Name	NASDAQ
Voting ordinary shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		18,012,556
Non-voting ordinary shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		3,509,682

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
ASSETS
Available-for-sale, at fair value	$ 2,041,724	$ 151,609
Funds held - directly managed	1,187,552	1,198,154
Equities, at fair value	729,721	367,125
Other investments, at fair value	2,524,420	1,957,757
Equity method investments	326,277	204,507
Total investments (Note 6 and Note 12)	13,207,513	11,242,061
Cash and cash equivalents	703,085	602,096
Restricted cash and cash equivalents	352,692	380,488
Premiums receivable	576,980	787,468
Deferred tax assets (Note 20)	170,984	10,124
Reinsurance balances recoverable on paid and unpaid losses (Note 8)	1,684,372	1,290,072
Reinsurance balances recoverable on paid and unpaid losses, fair value (Note 8 and Note 12)	695,518	739,591
Insurance balances recoverable (Note 11)	448,855	135,808
Funds held by reinsured companies	408,735	321,267
Deferred acquisition costs	153,505	121,101
Goodwill and intangible assets (Note 14)	216,468	218,725
Other assets	744,608	707,469
TOTAL ASSETS	19,363,315	16,556,270
LIABILITIES
Losses and loss adjustment expenses	7,808,116	6,535,449
Losses and loss adjustment expenses, fair value (Note 10 and Note 12)	2,621,122	2,874,055
Defendant asbestos and environmental liabilities (Note 11)	847,685	203,320
Unearned premiums	746,775	842,618
Insurance and reinsurance balances payable	373,180	388,086
Deferred tax liabilities (Note 20)	16,074	10,542
Debt obligations (Note 15)	1,191,207	861,539
Other liabilities	464,014	468,129
TOTAL LIABILITIES	14,068,173	12,183,738
COMMITMENTS AND CONTINGENCIES (Note 23)
REDEEMABLE NONCONTROLLING INTEREST (Note 16)	438,791	458,543
Preferred Shares:
Treasury shares, at cost (Series C Preferred Shares 2019 and 2018: 388,571)	(421,559)	(421,559)
Additional paid-in capital	1,836,778	1,804,664
Accumulated other comprehensive income	7,171	10,440
Retained earnings	2,887,892	1,976,539
Total Enstar Group Limited Shareholders’ Equity	4,842,183	3,901,933
Noncontrolling interest	14,168	12,056
TOTAL SHAREHOLDERS’ EQUITY	4,856,351	3,913,989
TOTAL LIABILITIES, REDEEMABLE NONCONTROLLING INTEREST AND SHAREHOLDERS’ EQUITY	19,363,315	16,556,270
Voting ordinary shares
Ordinary shares (par value $1 each, issued and outstanding 2019: 21,511,505; 2018: 21,459,997):
Ordinary shares	18,002	17,950
Series C non-voting convertible ordinary shares
Ordinary shares (par value $1 each, issued and outstanding 2019: 21,511,505; 2018: 21,459,997):
Ordinary shares	2,600	2,600
Series E non-voting convertible ordinary shares
Ordinary shares (par value $1 each, issued and outstanding 2019: 21,511,505; 2018: 21,459,997):
Ordinary shares	910	910
Series C Preferred Shares
Preferred Shares:
Preferred shares	389	389
Series D Preferred Shares
Preferred Shares:
Preferred shares	400,000	400,000
Series E Preferred Shares
Preferred Shares:
Preferred shares	110,000	110,000
Short-term Investments
ASSETS
Fixed maturity investments, trading	51,490	114,116
Available-for-sale, at fair value	128,335	0
Fixed maturity investments, trading
ASSETS
Fixed maturity investments, trading	6,346,329	7,248,793
Available-for-sale, at fair value	$ 1,913,389	$ 151,609

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fixed maturities, available-for-sale, at fair value, amortized cost	$ 2,042,454	$ 151,433
Ordinary shares, par value (dollars per share)	$ 1	$ 1
Ordinary shares, issued (shares)	21,511,505	21,459,997
Ordinary shares, outstanding (shares)	21,511,505	21,459,997
Voting ordinary shares
Ordinary shares, par value (dollars per share)	$ 1	$ 1
Ordinary shares, issued (shares)	18,001,823	17,950,315
Ordinary shares, outstanding (shares)	18,001,823	17,950,315
Series C non-voting convertible ordinary shares
Ordinary shares, issued (shares)	2,599,672	2,599,672
Ordinary shares, outstanding (shares)	2,599,672	2,599,672
Series E non-voting convertible ordinary shares
Ordinary shares, issued (shares)	910,010	910,010
Ordinary shares, outstanding (shares)	910,010	910,010
Series C Preferred Shares
Preferred shares, issued (shares)	388,571	388,571
Preferred shares, outstanding (shares)	388,571	388,571
Treasury shares (shares)	388,571	388,571
Series D Preferred Shares
Preferred shares, issued (shares)	16,000	16,000
Preferred shares, outstanding (shares)	16,000	16,000
Series E Preferred Shares
Preferred shares, issued (shares)	4,400	4,400
Preferred shares, outstanding (shares)	4,400	4,400
Short-term Investments
Fixed maturities, available-for-sale, at fair value, amortized cost	$ 128,311	$ 0
Fixed maturity investments, trading
Fixed maturities, available-for-sale, at fair value, amortized cost	$ 1,914,143	$ 151,433

Consolidated Statements of Earn

Consolidated Statements of Earnings - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
INCOME
Net premiums earned	$ 272,686	$ 270,325	$ 276,563	$ 335,287	$ 231,947	$ 264,597	$ 228,812	$ 170,219	$ 1,154,861	$ 895,575	$ 613,121
Fees and commission income	9,007	6,587	6,178	6,681	11,455	6,950	8,352	8,331	28,453	35,088	66,103
Net investment income	79,376	85,472	77,732	78,696	68,453	69,430	66,469	66,319	321,276	270,671	208,789
Net realized and unrealized gains (losses)	152,664	148,185	269,711	460,791	(158,213)	(57,223)	(54,418)	(143,030)	1,031,351	(412,884)	190,334
Other income	19,502	826	11,030	5,812	34,267	8,226	(9,351)	1,943	37,170	35,085	22,605
Total income	533,235	511,395	641,214	887,267	187,909	291,980	239,864	103,782	2,573,111	823,535	1,100,952
EXPENSES
Net incurred losses and loss adjustment expenses	121,416	222,417	216,338	312,404	187,698	153,974	92,819	19,534	872,575	454,025	193,551
Life and annuity policy benefits	(2,199)	0	2,194	96	786	423	(160)	(46)	91	1,003	4,015
Acquisition costs	95,026	50,282	66,855	93,788	55,106	54,242	53,334	30,108	305,951	192,790	96,906
General and administrative expenses	129,569	113,924	117,519	112,074	106,950	102,553	102,612	95,260	473,086	407,375	435,985
Interest expense	13,519	14,950	13,036	11,036	4,644	4,640	8,922	8,011	52,541	26,217	28,102
Net foreign exchange (gains) losses	12,189	(13,631)	(2,587)	(3,850)	1,279	1,040	(5,519)	5,868	(7,879)	2,668	17,537
Loss on sale of subsidiary									0	0	16,349
Total expenses	369,520	387,942	413,355	525,548	356,463	316,872	252,008	158,735	1,696,365	1,084,078	792,445
EARNINGS (LOSS) BEFORE INCOME TAXES	163,715	123,453	227,859	361,719	(168,554)	(24,892)	(12,144)	(54,953)	876,746	(260,543)	308,507
Income tax benefit (expense)	22,427	(14,597)	(7,518)	(4,749)	10,688	(746)	(3,646)	(172)	(4,437)	6,124	6,395
Earnings from equity method investments	11,722	17,703	17,713	8,772	8,488	3,317	15,645	14,697	55,910	42,147	5,904
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS									928,219	(212,272)	320,806
Net earnings from discontinued operations, net of income taxes									0	0	10,993
NET EARNINGS (LOSS)	197,864	126,559	238,054	365,742	(149,378)	(22,321)	(145)	(40,428)	928,219	(212,272)	331,799
Net loss (earnings) attributable to noncontrolling interest	4,900	109	2,713	2,148	42,955	11,489	8,389	(782)	9,870	62,051	(20,341)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	202,764	126,668	240,767	367,890	(106,423)	(10,832)	8,244	(41,210)	938,089	(150,221)	311,458
Dividends on preferred shares	(8,925)	(8,925)	(8,925)	(9,139)	(7,000)	(5,133)	0	0	(35,914)	(12,133)	0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$ 193,839	$ 117,743	$ 231,842	$ 358,751	$ (113,423)	$ (15,965)	$ 8,244	$ (41,210)	$ 902,175	$ (162,354)	$ 311,458
Basic:
Net earnings (loss) from continuing operations (dollars per share)									$ 42	$ (7.84)	$ 15.50
Net earnings (loss) from discontinued operations, net of income taxes (dollars per share)									0	0	0.56
Net earnings (loss) per ordinary share (dollars per share)	$ 9.02	$ 5.48	$ 10.79	$ 16.71	$ (5.29)	$ (0.74)	$ 0.40	$ (2.12)	42	(7.84)	16.06
Diluted:
Net earnings (loss) from continuing operations (dollars per share)									41.43	(7.84)	15.39
Net earnings from discontinued operations, net of income taxes (dollars per share)									0	0	0.56
Net earnings (loss) per ordinary share (dollars per share)	$ 8.89	$ 5.42	$ 10.70	$ 16.57	$ (5.29)	$ (0.74)	$ 0.40	$ (2.12)	$ 41.43	$ (7.84)	$ 15.95
Weighted average ordinary shares outstanding:
Basic (shares)									21,482,617	20,698,310	19,388,621
Diluted (shares)									21,775,066	20,904,176	19,527,591

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
NET EARNINGS (LOSS)	$ 928,219	$ (212,272)	$ 331,799
Other comprehensive income (loss), net of income taxes:
Unrealized holding gains (losses) on fixed income investments arising during the year	2,896	(2,284)	4,776
Reclassification adjustment for net realized gains (losses) included in net earnings	(3,894)	63	(491)
Unrealized gains (losses) arising during the year, net of reclassification adjustment	(998)	(2,221)	4,285
Change in currency translation adjustment	(2,428)	(202)	9,423
Reclassification to earnings on disposal of subsidiary	0	0	20,751
Total cumulative translation adjustment	(2,428)	(202)	30,174
Decrease in defined benefit pension liability	42	2,156	1,501
Total other comprehensive gain (loss)	(3,384)	(267)	35,960
Comprehensive income (loss)	924,835	(212,539)	367,759
Comprehensive loss (income) attributable to noncontrolling interest	9,985	62,291	(22,285)
COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	$ 934,820	$ (150,248)	$ 345,474

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Treasury Shares (Series C Preferred Shares)	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Cumulative translation adjustment	Defined benefit pension liability	Unrealized gains (losses) on investments	Retained Earnings	Noncontrolling Interest (excludes redeemable noncontrolling interests)	Voting ordinary sharesOrdinary Shares	Series C non-voting convertible ordinary sharesOrdinary Shares	Series E non-voting convertible ordinary sharesOrdinary Shares	Series C non-voting preferred sharesPreferred Stock	Series D Preferred SharesPreferred Stock	Series E preferred perpetual sharesPreferred Stock
Balance, beginning of year at Dec. 31, 2016			$ 1,380,109	$ (23,549)	$ (18,993)	$ (4,644)	$ 88	$ 1,847,550	$ 8,520	$ 16,175	$ 2,792	$ 405		$ 0	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issue of shares			450							35		0		0	0
Conversion of convertible securities										192	(192)
Issuance costs of preferred shares			0
Amortization of share-based compensation			14,508
Other comprehensive income (loss)	$ 35,960				9,413		2,352
Reclassification to earnings on disposal of subsidiary					20,751
Change in defined benefit pension liability	1,501					1,501
Net earnings (loss) attributable to Enstar Group Limited ordinary shareholders	311,458							331,799
Net loss (earnings) attributable to noncontrolling interest	(20,341)							(20,341)	722
Dividends on preferred shares								0
Change in redemption value of redeemable noncontrolling interests								(30,978)
Purchase of noncontrolling shareholders' interest in subsidiaries									0
Contribution of capital									22
Balance, end of year at Dec. 31, 2017		$ (421,559)	1,395,067	10,468	11,171	(3,143)	2,440	2,132,912	9,264	16,402	2,600	405	$ 389	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issue of shares			413,141							1,548		505		400,000	110,000
Conversion of convertible securities										0	0
Issuance costs of preferred shares			(14,643)
Amortization of share-based compensation			11,099
Other comprehensive income (loss)	(267)				(185)		(1,999)
Reclassification to earnings on disposal of subsidiary					0
Change in defined benefit pension liability	2,156					2,156
Net earnings (loss) attributable to Enstar Group Limited ordinary shareholders	(162,354)							(212,272)
Net loss (earnings) attributable to noncontrolling interest	62,051							62,051	2,743
Dividends on preferred shares								(12,133)
Change in redemption value of redeemable noncontrolling interests								7,554
Purchase of noncontrolling shareholders' interest in subsidiaries									0
Contribution of capital									49
Balance, end of year at Dec. 31, 2018	3,913,989	(421,559)	1,804,664	10,440	10,986	(987)	441	1,976,539	12,056	17,950	2,600	910	389	400,000	110,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issue of shares			583							52		0		0	0
Conversion of convertible securities										0	0
Issuance costs of preferred shares			0
Amortization of share-based compensation			31,531
Other comprehensive income (loss)	(3,384)				(2,438)		(873)
Reclassification to earnings on disposal of subsidiary					0
Change in defined benefit pension liability	42					42
Net earnings (loss) attributable to Enstar Group Limited ordinary shareholders	902,175							928,219
Net loss (earnings) attributable to noncontrolling interest	9,870							9,870	2,159
Dividends on preferred shares								(35,914)
Change in redemption value of redeemable noncontrolling interests								9,178
Purchase of noncontrolling shareholders' interest in subsidiaries									(47)
Contribution of capital									0
Balance, end of year at Dec. 31, 2019	$ 4,856,351	$ (421,559)	$ 1,836,778	$ 7,171	$ 8,548	$ (945)	$ (432)	$ 2,887,892	$ 14,168	$ 18,002	$ 2,600	$ 910	$ 389	$ 400,000	$ 110,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
OPERATING ACTIVITIES:
Net earnings (loss)	$ 928,219	$ (212,272)	$ 331,799
Net earnings from discontinued operations, net of income taxes	0	0	(10,993)
Adjustments to reconcile net earnings to cash flows used in operating activities:
Realized losses (gains) on sale of investments	(96,328)	27,633	(1,668)
Unrealized losses (gains) on investments	(935,023)	385,251	(188,666)
Depreciation and other amortization	35,583	33,295	36,115
Earnings from equity method investments	(55,910)	(42,147)	(5,904)
Sales and maturities of trading securities	5,829,277	4,802,224	6,111,607
Purchases of trading securities	(4,591,459)	(5,592,311)	(7,544,649)
Net loss on sale of subsidiary	0	0	16,349
Other non-cash items	33,857	11,857	41,087
Changes in:
Reinsurance balances recoverable on paid and unpaid losses	(350,243)	(268,039)	(530,857)
Funds held by reinsured companies	(87,468)	(126,897)	(93,310)
Losses and loss adjustment expenses	1,021,175	960,199	1,363,032
Defendant asbestos and environmental liabilities	(18,142)	(15,844)	(14,857)
Policy benefits for life and annuity contracts	(103,080)	(6,776)	(3,314)
Insurance and reinsurance balances payable	(15,227)	151,918	(157,741)
Unearned premiums	(95,843)	173,725	34,854
Premiums receivable	210,493	(212,423)	(19,026)
Other operating assets and liabilities	53,635	(229,465)	293,035
Net cash flows provided by (used in) operating activities	1,763,516	(160,072)	(343,107)
INVESTING ACTIVITIES:
Acquisitions, net of cash acquired	172,482	(245,151)	(4,185)
Sale of subsidiary, net of cash sold	0	0	126,611
Sales and maturities of available-for-sale securities	344,325	58,219	86,359
Purchase of available-for-sale securities	(2,212,204)	(10,386)	(14,848)
Purchase of other investments	(796,918)	(901,071)	(109,885)
Proceeds from other investments	582,662	436,396	232,827
Purchase of equity method investments	(69,213)	(155,440)	0
Other investing activities	(4,671)	(8,321)	(23,617)
Net cash flows provided by (used in) investing activities	(1,983,537)	(825,754)	293,262
FINANCING ACTIVITIES:
Net proceeds from the issuance of preferred shares	0	495,357	0
Dividends on preferred shares	(35,914)	(12,133)	0
Contribution by redeemable noncontrolling interest	0	49	22
Contribution by redeemable noncontrolling interest	13,127	55,377	0
Dividends paid to noncontrolling interest	(11,556)	(3,852)	(27,458)
Purchase of noncontrolling interest in subsidiaries	(47)	0	0
Receipt of loans	1,070,502	1,132,507	874,100
Repayment of loans	(742,574)	(914,319)	(912,140)
Net cash flows provided by (used in) financing activities	293,538	752,986	(65,476)
EFFECT OF EXCHANGE RATE CHANGES ON FOREIGN CURRENCY CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(324)	2,588	9,512
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	73,193	(230,252)	(105,809)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING OF YEAR	982,584	1,212,836	1,318,645
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, END OF YEAR	1,055,777	982,584	1,212,836
Supplemental Cash Flow Information:
Income taxes paid, net of refunds	5,012	17,610	13,192
Interest paid	49,457	25,240	21,487
Reconciliation to Consolidated Balance Sheets:
Cash, cash equivalents and restricted cash	$ 982,584	$ 1,212,836	$ 1,212,836

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	1. DESCRIPTION OF BUSINESS Enstar Group Limited ("Enstar") is a Bermuda-based holding company, formed in 2001. Enstar is a multi-faceted insurance group that offers innovative capital release solutions and specialty underwriting capabilities through its network of group companies in Bermuda, the United States, the United Kingdom, Continental Europe, Australia, and other international locations. Our ordinary shares are listed on the NASDAQ Global Select Market under the ticker symbol "ESGR". Unless the context indicates otherwise, the terms "Enstar," "we," "us" or "our" mean Enstar Group Limited and its consolidated subsidiaries and the term "Parent Company" means Enstar Group Limited and not any of its consolidated subsidiaries. Our business is organized into three segments: (i) Non-life Run-off: This segment comprises the operations of our subsidiaries that are running off their property and casualty and other non-life business. It also includes our management business, which manages the run-off portfolios of third parties through our service companies; (ii) Atrium: Atrium Underwriters Ltd. is a managing general agent at Lloyd’s of London ("Lloyd's"), which manages Syndicate 609. Through a corporate capital vehicle, Atrium 5 Ltd., we provide 25% of the syndicate’s underwriting capacity and capital (with the balance provided by traditional Lloyd’s Names). Atrium specializes in a wide range of industry classes, including marine, aviation and transit, property and casualty binding authorities, reinsurance, accident and health and non-marine direct and facultative; and (iii) StarStone: StarStone is a global specialty insurer that underwrites a diverse range of property, casualty and specialty insurance through its operations in Bermuda, the United States, the United Kingdom, and Continental Europe. Certain business of StarStone placed into run-off at the time of our acquisition of StarStone is recorded in our Non-life Run-off segment. Atrium and StarStone, our active underwriting operations, are reported as separate segments because they are managed and operated in separate and distinct manners. Atrium employees are not involved in the management or strategy of StarStone, nor are StarStone employees involved in the management or strategy of Atrium. Atrium and StarStone are monitored and reported upon separately and distinctly and their strategies and business plans are determined independently of each other. In addition to our three reportable segments, our other activities, which do not qualify as a reportable segment, include our corporate expenses, debt servicing costs, holding company income and expenses, foreign exchange and other miscellaneous items.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Significant Accounting Policies	2. SIGNIFICANT ACCOUNTING POLICIES Basis of Preparation The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP"). The consolidated financial statements include our assets, liabilities and results of operations as of December 31, 2019 and 2018 and for the years ended December 31, 2019 , 2018 and 2017 . Results of operations for acquired subsidiaries are included from the date of acquisition. All significant intercompany transactions and balances have been eliminated. Certain prior period amounts have been reclassified to conform to the current period presentation. These reclassifications had no impact on net earnings. Use of Estimates The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Our actual results could differ materially from our estimates. Accounting policies that we believe are most dependent on assumptions and estimates are considered to be our critical accounting policies and are related to the determination of: • liability for losses and loss adjustment expenses ("LAE"); • reinsurance balances recoverable on paid and unpaid losses; • defendant asbestos and environmental liabilities and related insurance balances recoverable; • valuation allowances on reinsurance balances recoverable and deferred tax assets; • impairment charges, including other-than-temporary impairments on investment securities classified as available-for-sale, and impairments on goodwill, intangible assets and deferred charge assets; • gross and net premiums written and net premiums earned; • fair value measurements of investments; • fair value estimates associated with accounting for acquisitions; • fair value estimates associated with loss portfolio transfer reinsurance agreements for which we have elected the fair value option; and • redeemable noncontrolling interests. (a) Premiums Non-Life Non-life premiums written are earned on a pro-rata basis over the period the coverage is provided. Reinsurance premiums are recorded at the inception of the policy, are based upon contractual terms and, for certain business, are estimated based on underlying contracts or from information provided by insureds and/or brokers. Changes in reinsurance premium estimates are expected and may result in adjustments in future periods. Any subsequent differences arising on such estimates are recorded as premiums written in the period in which they are determined. Certain non-life contracts are retrospectively rated and provide for a final adjustment to the premium based on the final settlement of all losses. Premiums on such contracts are adjusted based upon contractual terms, and management judgme nt is involved with respect to the estimate of the amount of losses that we expect to incur. Additional premiums are recognized at the time loss thresholds specified in the contract are exceeded and are earned over the coverage period, or are earned immediately if the period of risk coverage has passed. Premiums receivable Premiums receivable represent amounts currently due and amounts not yet due on insurance and reinsurance policies. Premiums for insurance policies and loss portfolio transfer reinsurance agreements are generally due at inception. Premiums for other reinsurance policies generally become due over the period of coverage based on the policy terms. We monitor the credit risk associated with premiums receivable, taking into consideration the impact of our contractual right to offset loss obligations or unearned premiums against premiums receivable. Amounts deemed uncollectible are charged to net earnings based on an expected loss approach. Changes in the estimates of premiums written will result in an adjustment to premiums receivable in the period they are determined. Unearned premiums and prepaid reinsurance premiums Unearned premiums represent the portion of premiums written that relate to the unexpired terms of policies in force. Premiums ceded are similarly pro-rated over the period the coverage is provided with the unearned portion being deferred as prepaid reinsurance premiums. (b) Acquisition Costs Acquisition costs, consisting principally of commissions and brokerage expenses and certain premium taxes and fees incurred at the time a contract or policy is issued and that vary with and are directly related to the successful efforts of acquiring new insurance contracts or renewing existing insurance contracts, are deferred and amortized over the period in which the related premiums are earned. Deferred acquisition costs are limited to their estimated realizable value by line of business based on the related unearned premiums, anticipated claims and claim expenses and anticipated investment income. A premium deficiency occurs if the sum of anticipated losses and loss adjustment expenses exceed unearned premiums, deferred acquisition costs and anticipated investment income. A premium deficiency is initially recognized by charging any deferred acquisition costs to expense to the extent required in order to eliminate the deficiency. If the premium deficiency exceeds the deferred acquisition costs then a liability is accrued for the excess deficiency. (c) Losses and LAE Non-life Run-off The liability for losses and LAE in the Non-life Run-off segment includes an amount determined from reported claims and an amount, based on historical loss experience and industry statistics, for losses incurred but not reported ("IBNR") determined using a variety of actuarial methods. These estimates are continually reviewed and are necessarily subject to the impact of future changes in factors such as claim severity and frequency, changes in economic conditions including the impact of inflation, legal and judicial developments, and medical cost trends. Our estimates, at inception and on an ongoing basis, do not include an estimate for potential future commutations and policy buybacks. Commutations and policy buybacks are often unique, and each commutation or policy buyback is separately negotiated. Therefore, the successful execution of one commutation or policy buyback does not necessarily impact the likelihood of other commutations or policy buybacks occurring in the future. We therefore exclude the impact of potential future commutations and policy buybacks in determining the liability for losses and LAE. While we believe that the liability for losses and LAE is adequate, the ultimate amount may be in excess of, or less than, the amounts provided. Adjustments will be reflected as part of the net increase or reduction in losses and LAE liabilities in the periods in which they become known. Premium and commission adjustments may be triggered by incurred losses, and any amounts are recorded in the same period that the related incurred loss is recognized. Commutations of acquired companies’ exposures have the effect of accelerating the payout of claims compared to the probability-weighted ranges of actuarially projected cash flows that we applied when estimating the fair values of assets and liabilities at the time of acquisition. Commutations and policy buybacks provide an opportunity for us to exit exposures to certain policies and insureds generally at a discount to our estimate of the ultimate liability and provide us with the ability to eliminate exposure to further losses. Commutations and policy buybacks can be beneficial to us as they legally extinguish liabilities in full, reduce the potential for future adverse loss development, and reduce future claims handling costs. Any material acceleration of payout together with the impact of any material loss reserve savings in any period will also accelerate the amortization of fair value adjustments and deferred charge assets in that period. Commutations are only executed directly with insureds or reinsureds and any g ains realized or losses incurred on the settlement of losses and LAE liabilities through commutations or policy buybacks are recognized upon the execution of a commutation or policy buyback with the insured or reinsured. Our estimate of the liability for losses and LAE does not consider historical commutations and policy buybacks and also does not include an estimate for potential future commutations and policy buybacks. Our insurance and reinsurance subsidiaries also establish provisions for LAE relating to run-off costs for the estimated duration of the run-off, which are included in the liability for losses and LAE. These provisions are assessed at each reporting date, and provisions relating to future periods are adjusted to reflect any changes in estimates of the periodic run-off costs or the duration of the run-off, including the impact of any acceleration of the run-off period that may be caused by commutations. Provisions relating to the current period together with any adjustment to future run-off provisions are included in net incurred losses and LAE in the consolidated statements of earnings. Atrium and StarStone The reserves for losses and LAE in the Atrium and StarStone segments include reserves for unpaid reported losses and for IBNR loss reserves. The reserves for unpaid reported losses and loss expenses are established by management based on reports from brokers, ceding companies and insureds and represent the estimated ultimate cost of events or conditions that have been reported to or specifically identified by us. The reserve for IBNR losses is established by us based on actuarially determined estimates of ultimate losses and loss expenses. Inherent in the estimate of ultimate losses and loss expenses are expected trends in claim severity and frequency and other factors which may vary significantly as claims are settled. Accordingly, ultimate losses and loss expenses may differ from the amounts recorded in the consolidated financial statements. These estimates are reviewed regularly and, as experience develops and new information becomes known, the reserves are adjusted as necessary. Such adjustments, if any, will be recorded in earnings in the period in which they become known. Prior period development arises from changes to loss estimates recognized in the current year that relate to loss reserves established in prev ious calendar years. Components of Net Incurred Losses and LAE Included within the total net incurred losses and LAE on our consolidated statement of earnings are the following items: • Net losses paid: paid losses and LAE, net of related reinsurance recoveries. • Net change in case and LAE reserves: the change in case reserves and associated LAE, net of related reinsurance recoveries. • Net change in IBNR reserves: the change in IBNR reserves, net of related reinsurance recoveries. • Increase (reduction) in estimates of net ultimate losses: the total of net losses paid, net change in case and LAE reserves and the net change in IBNR. This includes the net impact of commutations and policy buybacks on the liability for losses and LAE reserves and reinsurance recoveries. • Increase (reduction) in provisions for unallocated LAE: the net change in our provision for unallocated LAE. • Amortization of deferred charge assets: the amortization of the deferred charge assets associated with assumed retroactive reinsurance contracts, where the estimated ultimate losses assumed at the inception of the contracts is greater than the premium consideration received. • Amortization of fair value adjustments: the amortization of the fair value adjustments associated with acquired companies, where the assumed losses and LAE reserves and the acquired reinsurance recoveries are fair valued on acquisition. • Changes in fair value - fair value option: the changes in the fair value for reinsurance agreements where we have elected the fair value option. The change in fair value component includes the changes in the discounted cash flows and risk margin. The underlying net losses paid, net change in case and LAE reserves and the net change in IBNR reserves relating to these reinsurance agreements for which we have elected the fair value option are included within the appropriate line items described above. • Net incurred losses and LAE: the total of increase (reduction) in estimates of net ultimate losses, increase (reduction) in provisions for unallocated LAE, amortization of deferred charge assets, amortization of fair value adjustments and changes in fair value - fair value option. (d) Defendant Asbestos and Environmental Liabilities We acquired DCo on December 30, 2016, and Morse TEC on October 30, 2019, as described in Note 3 - "Acquisitions" . DCo and Morse TEC hold liabilities associated with personal injury asbestos claims and environmental claims arising from their legacy manufacturing operations. DCo and Morse TEC continue to process asbestos personal injury claims. Defendant asbestos and environmental liabilities on our consolidated balance sheets include amounts for indemnity and defense costs for pending and future claims, determined using standard actuarial techniques for asbestos-related exposures. Defendant asbestos and environmental liabilities also include amounts for environmental liabilities associated with DCo's and Morse TEC's properties. (e) Reinsurance Balances Recoverable on Paid and Unpaid Losses Amounts billed to, and due from, reinsurers resulting from paid movements in the underlying business are calculated in accordance with the terms of the individual reinsurance contracts. Similarly, reinsurance balances recoverable on paid and unpaid losses related to our case reserves are calculated by applying the terms of any applicable reinsurance coverage to movements in the underlying case reserves. Our estimate of reinsurance balances recoverable on paid and unpaid losses related to IBNR reserves is recognized on a basis consistent with the underlying IBNR reserves. Our reinsurance balances recoverable on paid and unpaid losses are presented net of a provision for uncollectible amounts, reflecting the amount deemed not collectible due to credit quality, collection problems due to the location of the reinsurer, contractual disputes with reinsurers over individual contentious claims, contract language or coverage issues. (f) Insurance Balances Recoverable Amounts billed to and due from insurers providing coverage for our defendant asbestos liabilities are calculated in accordance with the terms of the individual insurance contracts. The insurance balances recoverable related to our defendant asbestos liabilities are presented net of a provision for uncollectible amounts, reflecting the amount deemed not collectible primarily due to credit quality and contractual disputes with insurers over coverage issues. (g) Investments, Cash and Cash Equivalents Short-term investments and fixed maturity investments Short-term investments comprise investments with a maturity greater than three months up to one year from the date of purchase. Fixed maturities comprise investments with a maturity of greater than one year from the date of purchase. Short-term and fixed maturity investments classified as trading are carried at fair value, with realized and unrealized holding gains and losses included in net earnings and reported as net realized and unrealized gains and losses. Short-term and fixed maturity investments classified as available-for-sale are carried at fair value, with unrealized gains and losses excluded from net earnings and reported as a separate component of accumulated other comprehensive income (loss) ("AOCI") . Realized gains and losses on sales of investments classified as available-for-sale are recognized in the consolidated statements of earnings. The costs of short-term and fixed maturity investments are adjusted for amortization of premiums and accretion of discounts, recognized using the effective yield method and included in net investment income. For mortgage-backed and asset-backed investments, and any other holdings for which there is a prepayment risk, prepayment assumptions are evaluated and reviewed on a regular basis. Investment purchases and sales are recorded on a trade-date basis. Realized gains and losses on the sale of investments are based upon specific identification of the cost of investments. Other-Than-Temporary Impairments Fixed maturity investments classified as available-for-sale are reviewed quarterly to determine if they have sustained an impairment of value that is, based on our judgment, considered to be other than temporary. The process includes reviewing each fixed maturity investment whose fair value is below amortized cost and: (1) determining if we have the intent to sell the fixed maturity investment; (2) determining if it is more likely than not that we will be required to sell the fixed maturity investment before its anticipated recovery; and (3) assessing whether a credit loss exists, that is, whether we expect that the present value of the cash flows expected to be collected from the fixed maturity investment is less than the amortized cost basis of the investment. In assessing whether it is more likely than not that we will be required to sell a fixed maturity investment before its anticipated recovery, we consider various factors including our future cash flow requirements, legal and regulatory requirements, the level of our cash, cash equivalents, short-term investments and fixed maturity investments available-for-sale in an unrealized gain position, and other relevant factors. In evaluating credit losses, we consider a variety of factors in the assessment of a fixed maturity investment including: (1) the time period during which there has been a significant decline below cost; (2) the extent of the decline below cost and par; (3) the potential for the investment to recover in value; (4) an analysis of the financial condition of the issuer; (5) the rating of the issuer; and (6) failure of the issuer of the investment to make scheduled interest or principal payments. If we conclude that an investment is other-than-temporarily impaired ("OTTI"), then the difference between the fair value and the amortized cost of the investment is presented as an OTTI charge in the consolidated statements of earnings, with an offset for any non-credit related loss component of the OTTI charge to be recognized in other comprehensive income. Accordingly, only the credit loss component of the OTTI amount would have an impact on our earnings. Equities We hold investments in publicly traded equities and exchange-traded funds as well as in privately held equities. Our equity investments are carried at fair value with realized and unrealized holding gains and losses included in net earnings and reported as net realized and unrealized gains and losses. Other investments, at fair value Other investments include investments in limited partnerships and limited liability companies (collectively "private equities") and fixed income funds, hedge funds, equity funds, private credit funds and collateralized loan obligation ("CLO") equity funds that carry their investments at fair value, as well as direct investments in CLO equities. These other investments are stated at fair value, which ordinarily will be the most recently reported net asset value as advised by the fund manager or administrator. Many of our fund investments publish net asset values on a daily basis and provide daily liquidity; others report on a monthly basis. Private equities typically report quarterly. The change in fair value is included in net realized and unrealized gains and losses on investments and recognized in net earnings. Equity method investments Investments in which the Company has significant influence over the operating and financial policies of the investee are classified as equity method investments and are accounted for using the equity method of accounting. In applying the equity method of accounting, investments are initially recorded at cost and are subsequently adjusted based on the Company's proportionate share of net income or loss of the investee, net of any distributions received from the investee. Adjustments are based on the most recently available financial information from the investee. Changes in the carrying value of such investments are recorded in our consolidated statements of earnings as earnings (losses) from equity method investments. Any decline in the value of our equity method investments considered by management to be other-than-temporary is reflected in our consolidated statements of earnings in the period in which it is determined. Cash and cash equivalents Cash equivalents includes money market funds, fixed interest deposits and all highly liquid debt instruments purchased with an original maturity of three months or less. (h) Funds Held Under funds held arrangements, the reinsured company has retained funds that would otherwise have been remitted to our reinsurance subsidiaries. The funds balance is credited with investment income and losses payable are deducted. Funds held are shown under two categories on the consolidated balance sheets, where funds held upon which we receive the underlying portfolio economics are shown as "Funds held - directly managed", and funds held where we receive a fixed crediting rate are shown as "Funds held by reinsured companies". Funds held by reinsured companies are carried at cost. Funds held - directly managed, carried at fair value, represents the aggregate of funds held at cost and the value of an embedded derivative. The embedded derivative relates to our contractual right to receive the return on the underlying investment portfolio economics. The investment returns on both categories of funds held are recognized in net investment income and net realized and unrealized gains (losses). The revaluation of the embedded derivative is included in net unrealized gains (losses). (i) Fees and Commission Income Fees and commission income primarily includes profit commissions earned from managed Lloyd's syndicates as well as fees earned under fronting and consulting arrangements with third-party clients, which are recorded on an accrual basis. (j) Foreign Exchange Our reporting currency is the U.S. dollar. Assets and liabilities of entities whose functional currency is not the U.S. dollar are translated at period end exchange rates. Revenues and expenses of such foreign entities are translated at average exchange rates during the year. The effect of the currency translation adjustments for these foreign entities is included in accumulated other comprehensive income (loss). Other foreign currency assets and liabilities that are considered monetary items are translated at exchange rates in effect at the balance sheet date. Foreign currency revenues and expenses are translated either at transaction date exchange rates or using an appropriately weighted average exchange rate for the reporting period. These exchange gains and losses are recognized in net earnings. (k) Share-based Compensation We primarily use three types of share-based compensation arrangements: (i) restricted shares, restricted share units and performance share units, (ii) cash-settled stock appreciation rights ("SARs") and (iii) shares issued under our employee share purchase plans. With the exception of SARs and the incentive plan awards issued to certain employees of Atrium and StarStone, our share-based compensation awards qualify for equity classification. The fair value of the compensation cost is measured at the grant date and is expensed over the service period of the award. The SARs, the Atrium and StarStone incentive plan awards are classified as liability awards. Liability classified awards are recorded at fair value within other liabilities in the consolidated balance sheet with changes in fair value relating to the vested portion of the award recorded within general and administrative expenses in the consolidated statements of earnings. (l) Derivative Instruments We utilize derivative instruments in our foreign currency and interest rate risk management strategies and recognize all derivatives as either assets or liabilities in the consolidated balance sheets and carry them at the fair value of the specific instrument utilized. Changes in the fair value as well as realized gains or losses on derivative instruments are recognized in net earnings if they are not designated as qualifying hedging instruments or if the criteria for establishing a perfectly effective designated hedging relationship for our net investment hedges has not been met. However, if a designated net investment hedge is deemed to be perfectly effective, then we recognize the changes in the fair value of the underlying hedging instrument in accumulated other comprehensive income (loss) until the application of hedge accounting is discontinued. Any cumulative gains or losses arising on designated net investment hedges are deferred in accumulated other comprehensive income (loss) until the cumulative translation adjustment ("CTA") from the underlying hedged net investment is recognized in net earnings due to a disposal, deconsolidation or substantial liquidation. Certain of our funds held arrangements also contain embedded derivatives as described above, which are carried at fair value. In addition, we also hold equity call options carried at fair value, as part of our investment strategy. (m) Income Taxes Certain of our subsidiaries and branches operate in jurisdictions where they are subject to taxation. Current and deferred tax expense or benefit is allocated to net earnings (loss), or, in certain cases, to discontinued operations or other comprehensive income (loss). Current tax is recognized and measured upon enacted tax laws and rates applicable in the relevant jurisdiction in the period in which the income tax becomes accruable or realizable. Deferred taxes are provided for temporary differences between the carrying amount of assets and liabilities used in the financial statements and the tax basis used in the various jurisdictional tax returns. When our assessment indicates that all or some portion of deferred tax assets will not be realized, a valuation allowance is recorded against the deferred tax assets to reduce the assets to the amount more likely than not to be realized. We recognize the benefit relating to tax positions only where the position is more likely than not to be sustained assuming examination by tax authorities. A recognized tax benefit is measured as the largest amount that is greater than 50 percent likely of being realized upon settlement. A liability or other adjustment is recognized for any tax benefit (along with any interest and penalty, if applicable) claimed in a tax return in excess of the amount allowed to be recognized in the financial statements under U.S. GAAP. Any changes in amounts recognized are recorded in the period in which they are determined. (n) Earnings Per Share Basic earnings per share is based on the weighted average number of ordinary shares outstanding and excludes potentially dilutive securities such as restricted shares, restricted share units, warrants, options and convertible securities. Diluted earnings per share is based on the weighted average number of ordinary and ordinary share equivalents outstanding calculated using the treasury stock method for all potentially dilutive securities. When the effect of dilutive securities would be anti-dilutive, these securities are excluded from the calculation of diluted earnings per share. (o) Acquisitions, Goodwill and Intangible Assets The acquisition method is used to account for all business acquisitions. This method requires that we record the acquired assets and liabilities at their estimated fair value. The fair values of each of the acquired reinsurance assets and liabilities are derived from probability-weighted ranges of the associated projected cash flows, based on actuarially prepared information and management’s run-off strategy. Our run-off strategy, as well as that of other run-off market participants, is expected to be different from the seller's as generally sellers are not specialized in running off insurance and reinsurance liabilities whereas we and other market participants do specialize in such run-offs. The key assumptions used by us and, we believe, by other run-off market participants in the valuation of acquired companies are (i) the projected payout, timing and amount of claims liabilities; (ii) the related projected timing and amount of reinsurance collections; (iii) an appropriate discount rate, which is applied to determine the present value of the future cash flows; (iv) the estimated unallocated LAE to be incurred over the life of the run-off; (v) the impact of any accelerated run-off strategy; and (vi) an appropriate risk margin. The difference between the nominal carrying values of the acquired reinsurance liabilities and assets as of the acquisition date and their fair value is recorded as a fair value adjustment ("FVA") on the consolidated balance sheet. The FVA is amortized over the estimated payout period of the acquired outstanding losses and LAE and reinsurance balances recoverable. To the extent the actual payout experience after the acquisition is materially faster or slower than anticipated at the time of the acquisition as a result of (i) our active claims management strategies, which include commutations and policy buybacks , (ii) an adjustment to the estimated ultimate loss reserves, (iii) changes in bad debt provisions, or (iv) changes in estimates of future run-off costs following accelerated payouts, then the amortization of the FVA is adjusted to reflect such changes. The difference between the fair value of net assets acquired and the purchase price is recorded as goodwill and included as an asset on the consolidated balance sheet or as a gain from bargain purchase in the consolidated statements of earnings. Goodwill is established initially upon acquisition and assessed at least annually for impairment. If the goodwill asset is determined to be impaired it is written down in the period in which the determination is made. Intangible assets represent both the definite-lived and indefinite-lived intangible assets arising from the acquisitions of Atrium and StarStone. Definite-lived intangible assets are amortized over their useful lives with the amortization expense being recognized in the consolidated statements of earnings. Indefinite-lived intangible assets are not subject to amortization. The carrying values of intangible assets are reviewed for indicators of impairment at least annually. Impairment is recognized if the carrying values of the definite-lived intangible assets are not recoverable from their undiscounted cash flows and is measured as the amount by which the carrying value exceeds the fair value. Similarly, for indefinite-lived intangible assets, i f the carrying value of the asset exceeds its fair value, then an impairment loss is recognized in an amount equal to the excess. (p) Retroactive Reinsurance Retroactive reinsurance policies provide indemnification for losses and LAE with respect to past loss events. In our Non-life Run-off segment we use the balance sheet accounting approach for assumed loss portfolio transfers, whereby at the inception of the contract there are no premiums or losses recorded in earnings. Deferred Charge Assets If, at the inception of a Non-life Run-off retroactive reinsurance contract, the estimated undiscounted ultimate losses payable are in excess of the premiums received, a deferred charge asset is recorded for the excess. The premium consideration that we charge the ceding companies may be lower than the undiscounted estimated ultimate losses payable due to the time value of money. After receiving the premium consideration in full from our cedents at the inception of the contract, we invest the premium received over an extended period of time, thereby generating investment income. We expect to generate profits from these retroactive reinsurance policies when taking into account the premium received and expected investment income, less contractual obligations and expenses. Deferred charge assets, recorded in other assets, are amortized over the estimated claim payment period of the related contract with the periodic amortization reflected in earnings as a component of losses and LAE. The amortizatio

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Acquisitions	3. ACQUISITIONS 2019 Morse TEC Overvie w On October 30, 2019 , we completed the acquisition of Morse TEC LLC ("Morse TEC") through our subsidiary, Enstar Holdings (US) LLC for $nil purchase price. Morse TEC holds approximately $0.7 billion in liabilities associated with personal injury asbestos claims and environmental claims arising from BorgWarner's legacy manufacturing operations. We applied the acquisition method to account for the Morse TEC transaction as required by ASC 805 - Business Combinations , with no goodwill or gain from bargain purchase being recorded on the acquisition. In addition, no intangible assets were identified for recognition on the acquisition. Fair Value of Net Assets Acquired and Liabilities Assumed The following table summarizes the fair values of the assets acquired and liabilities assumed in the Morse TEC transaction at the acquisition date, which have all been allocated to the Non-life Run-off segment. ASSETS Cash and cash equivalents $ 171,412 Deferred tax assets 140,000 Other assets - insurance balances receivable 371,116 TOTAL ASSETS 682,528 LIABILITIES Defendant asbestos and environmental liabilities 662,507 Other liabilities 20,021 TOTAL LIABILITIES $ 682,528 NET ASSETS ACQUIRED AT FAIR VALUE — Morse TEC 's Results Included in the Consolidated Statement of Earnings The table below summarizes the results of the Morse TEC operations, which are included in our consolidated statement of earnings from the acquisition date to December 31, 2019: Net investment income $ 488 General and administrative expenses (1,459 ) Other expenses (1,512 ) Net loss $ (2,483 ) Supplemental Pro Forma Financial Information The following unaudited pro forma condensed combined statement of earnings for the years ended December 31, 2019 and 2018 combines our historical consolidated statements of earnings with those of Morse TEC , giving effect to the business combination transaction as if it had occurred on January 1, 2019 and 2018, respectively. The unaudited pro forma financial information presented below is for informational purposes only and is not necessarily indicative of the results of operations that would have been achieved if the acquisition of Morse TEC had taken place at the beginning of each period presented, nor is it indicative of future results. 2019 Enstar Group Limited Morse TEC Pro Forma Adjustments Enstar Group Limited - Pro forma Total income $ 2,629,021 $ 76,480 $ (488 ) $ 2,705,013 Total expenses (1,700,802 ) (8,918 ) 1,459 (1,708,261 ) Total noncontrolling interest 9,870 — — 9,870 Net earnings (loss) attributable to Enstar Group Limited $ 938,089 $ 67,562 $ 971 $ 1,006,622 The following table summarizes the pro-forma adjustments in the table above: Income (a) Total income for the period subsequent to the acquisition of Morse TEC already included within Enstar's full year results $ (488 ) Expenses (a) Total expenses for the period subsequent to the acquisition of Morse TEC already included within Enstar's full year results $ 1,459 2018 Enstar Group Limited Morse TEC Enstar Group Limited - Pro forma Total income $ 865,682 $ 42,766 $ 908,448 Total expenses (1,077,954 ) (30,187 ) (1,108,141 ) Total noncontrolling interest 62,051 — 62,051 Net earnings (loss) attributable to Enstar Group Limited $ (150,221 ) $ 12,579 $ (137,642 ) 2018 Maiden Re North America Overvie w On December 27, 2018 , we completed the acquisition of Maiden Reinsurance North America, Inc. (“ Maiden Re North America ”) from a subsidiary of Maiden Holdings, Ltd. ("Maiden Holdings"). Maiden Re North America is an insurance company domiciled in Missouri that provides property and casualty treaty reinsurance, casualty facultative reinsurance and accident and health treaty reinsurance. As part of the transaction, we also novated and assumed certain reinsurance agreements from Maiden Holdings' Bermuda reinsurer, including certain reinsurance agreements with Maiden Re North America . Refer to Note 4 - "Significant New Business" for additional information relating to these reinsurance agreements. We have operated the business in run-off since we acquired it. Purchase Price The total cash paid in the transaction was $286.4 million , subject to certain post-closing adjustments. The components of the consideration paid to acquire all of the outstanding shares of Maiden Re North America were as follows: Cash paid $ 286,375 Adjustment for the fair value of preexisting relationships 10,273 Total purchase price $ 296,648 Net assets acquired at fair value (excluding preexisting relationships) $ 296,648 Excess of purchase price over fair value of net assets acquired $ — The purchase price was allocated to the acquired assets and liabilities of Maiden Re North America based on their estimated fair values at the acquisition date. Adjustment for the Fair Value of Preexisting Relationships Enstar had contractual preexisting relationships with Maiden Re North America , which were deemed to be effectively settled at fair value on the acquisition date. The differences between the carrying value and the fair value of the preexisting relationships was included as part of the purchase price in accordance with ASC 805 - Business Combinations . The fair value of the balances relating to preexisting reinsurance relationships with Maiden Re North America were deemed to equal their carrying values given their short-term nature and the expectation that they would all be settled within twelve months following acquisition. Fair Value of Net Assets Acquired and Liabilities Assumed The following table summarizes the fair values of the assets acquired and liabilities assumed (excluding preexisting relationships and net of the intercompany cession assumed as part of the transaction) in the Maiden Re North America transaction at the acquisition date, which have all been allocated to the Non-life Run-off segment. ASSETS Fixed maturities, trading, at fair value $ 1,098,593 Short-term investments, trading, at fair value 3,508 Total investments 1,102,101 Cash and cash equivalents 12,035 Restricted cash and cash equivalents 26,871 Premiums receivable 138,378 Prepaid reinsurance premiums 3,257 Reinsurance balances recoverable 87,018 Other assets 96,669 TOTAL ASSETS $ 1,466,329 LIABILITIES Losses and LAE $ 1,027,367 Unearned premiums 85,696 Other liabilities 56,618 TOTAL LIABILITIES 1,169,681 NET ASSETS ACQUIRED AT FAIR VALUE $ 296,648 Maiden Re North America 's Results Included in the Consolidated Statement of Earnings The table below summarizes the results of the Maiden Re North America operations, which are included in our consolidated statement of earnings from the acquisition date to December 31, 2018: Net investment income $ 675 Net unrealized gains 3,749 General and administrative expenses (435 ) Net earnings $ 3,989 KaylaRe Overvie w On May 14, 2018 , the Company acquired all of the outstanding shares and warrants of KaylaRe Holdings, Ltd. ("KaylaRe"). In consideration for the acquired shares and warrants of KaylaRe, the Company issued an aggregate of 2,007,017 ordinary shares to the shareholders of KaylaRe, comprising 1,501,778 voting ordinary shares and 505,239 Series E non-voting ordinary shares. Effective May 14, 2018 , we consolidated KaylaRe into our consolidated financial statements, and any balances between KaylaRe and Enstar are now eliminated upon consolidation. Effective September 30, 2019, KaylaRe and KaylaRe Ltd. merged with Cavello Bay Reinsurance Limited, a wholly owned subsidiary of the Company, with Cavello Bay Reinsurance Limited as the surviving company. Refer to Note 21 - "Related Party Transactions" for additional information relating to KaylaRe. Purchase Price The components of the consideration paid to acquire all of the outstanding shares and warrants of KaylaRe were as follows: Fair value of Enstar ordinary shares issued $ 414,750 Fair value of previously held equity method investment 336,137 Adjustment for the fair value of preexisting relationships 37,169 Total purchase price $ 788,056 Net assets acquired at fair value (excluding preexisting relationships) $ 746,320 Excess of purchase price over fair value of net assets acquired $ 41,736 The purchase price was allocated to the acquired assets and liabilities of KaylaRe based on their estimated fair values at the acquisition date. We recognized goodwill of $41.7 million on the transaction, primarily attributable to (i) the capital synergies from integrating KaylaRe into our group capital structure, (ii) investment management capabilities on a total return basis, and (iii) the incremental acquired capital to be utilized for future non-life run-off transactions. Fair Value of Enstar Ordinary Shares Issued The fair value of the Enstar ordinary shares issued was based on the closing price of Enstar's voting ordinary shares of $206.65 as of May 14, 2018 , the date the transaction closed. Enstar's non-voting ordinary shares are economically equivalent to Enstar's voting ordinary shares. Number of Enstar ordinary shares issued 2,007,017 Closing price of Enstar voting ordinary shares as of May 14, 2018 $ 206.65 Fair value of Enstar ordinary shares issued to shareholders of KaylaRe $ 414,750 Fair Value of Previously Held Equity Method Investment Prior to the close of the transaction, Enstar held a 48.2% interest in KaylaRe, which was accounted for as an equity method investment in accordance with ASC 323 - Investments - Equity Method and Joint Ventures . The acquisition of the remaining 51.8% equity interest in KaylaRe was considered a step acquisition, whereby the Company remeasured the previously held equity method investment to fair value. The Company considered multiple factors in determining the fair value of the previously held equity method investment, including (i) the price negotiated with the selling shareholders for the 51.8% equity interest in KaylaRe, (ii) recent market transactions for similar companies, and (iii) current trading multiples for comparable companies. Based on this analysis, a valuation multiple of 1.05 to KaylaRe's carrying book value was determined to be appropriate to remeasure the previously held equity method investment at fair value. This resulted in the recognition of a gain of $16.0 million on completion of the step acquisition of KaylaRe, which was recorded in earnings (losses) from equity method investments for the three and six months ended June 30, 2018. Carrying value of previously held equity method investment prior to the close of the transaction $ 320,130 Price-to-book multiple 1.05 Fair value of previously held equity method investment prior to the close of the transaction $ 336,137 Gain recognized on remeasurement of previously held equity method investment to fair value $ 16,007 Adjustment for the Fair Value of Preexisting Relationships Enstar had contractual preexisting relationships with KaylaRe, which were deemed to be effectively settled at fair value on the acquisition date. The differences between the carrying value and the fair value of the preexisting relationships was included as part of the purchase price in accordance with ASC 805 - Business Combinations . The fair value of the balances relating to preexisting reinsurance relationships with KaylaRe was determined using a discounted cash flow approach and, where applicable, consideration was given to stated contractual settlement provisions, when determining the loss to be recorded on the deemed settlement of these preexisting relationships. The fair values of the balances arising from the non-reinsurance preexisting relationships with KaylaRe were deemed to equal their carrying values given their short-term nature and the expectation that they would all be settled within the next twelve months. As a result of effectively settling all the contractual preexisting relationships with KaylaRe, the Company recognized a loss of $15.6 million , which was recorded in other income (loss) in the three and six months ended June 30, 2018, as summarized below: ASSETS Carrying value Fair value Loss on deemed settlement Funds held by reinsured companies $ 386,793 $ 386,793 $ — Deferred acquisition costs/Value of business acquired 33,549 40,268 6,719 TOTAL ASSETS 420,342 427,061 6,719 LIABILITIES Losses and LAE 339,747 333,205 (6,542 ) Unearned premiums 105,602 105,602 — Insurance and reinsurance balances payable 25,897 23,559 (2,338 ) Other liabilities 1,864 1,864 — TOTAL LIABILITIES 473,110 464,230 (8,880 ) NET ASSETS (LIABILITIES) $ (52,768 ) $ (37,169 ) $ 15,599 Fair Value of Net Assets Acquired and Liabilities Assumed The following table summarizes the fair values of the assets acquired and liabilities assumed (excluding preexisting relationships) in the KaylaRe transaction at the acquisition date, which have all been allocated to the Non-life Run-off segment. ASSETS Fixed maturities, trading, at fair value $ 126,393 Other investments, at fair value 626,476 Total investments 752,869 Cash and cash equivalents 5,657 Premiums receivable 10,965 Deferred acquisition costs 275 Other assets 614 TOTAL ASSETS $ 770,380 LIABILITIES Losses and LAE $ 4,059 Unearned premiums 10,984 Insurance and reinsurance balances payable 13 Other liabilities 9,004 TOTAL LIABILITIES 24,060 NET ASSETS ACQUIRED AT FAIR VALUE $ 746,320 KaylaRe's Results Included in the Consolidated Statement of Earnings The table below summarizes the results of the KaylaRe operations, which are included in our consolidated statement of earnings from the acquisition date to December 31, 2018: Premiums earned $ 13,627 Incurred losses and LAE (12,364 ) Acquisition costs (341 ) Underwriting income 922 Net investment income 3,096 Net unrealized gains (47,769 ) General and administrative expenses (2,164 ) Net loss $ (45,915 )

Significant New Business

Significant New Business	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Significant New Business	4. SIGNIFICANT NEW BUSINESS 2020 AXA Group On February 24, 2020, we entered into a loss portfolio transfer reinsurance agreement with AXA XL, a division of AXA, to reinsure specified legacy construction general liability multi-year policies. We will assume reinsurance reserves of approximately $225.0 million in the transaction. Completion of the transaction is subject to, among other things, regulatory approvals and satisfaction of various closing conditions. The transaction is expected to close in the first half of 2020. Munich Re On September 10, 2019 , we signed an agreement with Great Lakes Insurance SE and HSB Engineering Insurance Limited, both subsidiaries of Munich Reinsurance Company ("Munich Re"), pursuant to which we will acquire certain portfolios from their Australian branches. In the transaction, which is subject to regulatory and Federal Court of Australia approval, we will receive total assets of approximately AUD$228.2 million (approximately $160.3 million ) for assuming the associated net insurance reserves, which primarily relate to long tail insurance business. We are pursuing a portfolio transfer of the insurance business under Division 3A of Part III of Australia’s Insurance Act 1973 (Cth), which would provide legal finality for Munich Re and its subsidiaries. This transaction is expected to close in 2020. 2019 Zurich On October 1, 2019 , we completed a reinsurance transaction with Zurich Insurance Group ("Zurich"), pursuant to which we reinsured certain of Zurich's U.S. asbestos and environmental liability insurance portfolios. In the transaction, we assumed $622.9 million of gross reserves, relating to 1986 and prior year business, for reinsurance premium of $465.5 million and recorded a deferred charge of $115.8 million . We have ceded 10% Maiden ADC On August 5, 2019, we and Maiden Reinsurance Ltd. (“Maiden Re Bermuda”) completed a transaction pursuant to a Master Agreement with Maiden Holdings, Ltd. and Maiden Re Bermuda to provide adverse development cover reinsurance to Maiden Re Bermuda, effective January 1, 2019. In the transaction, Maiden Re Bermuda ceded and we assumed as retrocessionaire Maiden Re Bermuda's liability under its quota share agreement with the Bermuda subsidiary ("AmTrust Bermuda") of AmTrust Financial Services, Inc. (“AmTrust”). The adverse development cover reinsurance is for losses incurred on or prior to December 31, 2018 in excess of a $2.2 billion retention up to a $600.0 million limit, in exchange for a premium of $445.0 million . We assumed total gross reserves of $530.2 million and recorded a deferred charge of $85.2 million Amerisure On April 11, 2019 , we completed a loss portfolio transfer reinsurance agreement with Amerisure Mutual Insurance Company ("Amerisure") and Allianz Risk Transfer (Bermuda) Limited (“ART Bermuda”). In the transaction, Amerisure ceded, and each of Enstar and ART Bermuda severally assumed, a 50% quota share of the construction defect losses incurred by Amerisure and certain of its subsidiaries on or before December 31, 2012. Under the agreement, which was effective as of January 1, 2019, we assumed $48.3 million of gross reserves in exchange for consideration of $45.5 million and recorded a deferred charge asset of $2.9 million AmTrust RITC Transactions On February 14, 2019 , we completed four RITC transactions with Syndicates 1206, 1861, 2526 and 5820 (collectively the "AmTrust RITC Transactions"), managed by AmTrust Syndicates Limited, under which we reinsured to close the 2016 and prior underwriting years. We assumed, among other items, gross loss reserves of £703.8 million ( $897.1 million ) and net loss reserves of £486.8 million ( $620.4 million ) relating to the portfolios in exchange for consideration of £539.9 million ( $688.2 million ) and recorded a deferred charge asset of $20.6 million . We have an investment in AmTrust, as described further in Note 21 - "Related Party Transactions" . 2018 Allianz Effective December 31, 2018, we and Allianz SE ("Allianz") amended the January 1, 2016 reinsurance agreement between our subsidiary and Allianz, which related to our reinsurance of certain U.S. workers' compensation, construction defect, and asbestos, pollution and toxic tort business originally held by Fireman's Fund Insurance Company. The amendment increased the original sub-limit related to asbestos & environmental (“A&E”) liabilities in exchange for a premium of $70.0 million Maiden LPT On December 27, 2018 , as part of the acquisition of Maiden Re North America as discussed in Note 3 - "Acquisitions" , we also novated and assumed certain reinsurance agreements from Maiden Re Bermuda, including certain affiliate reinsurance agreements with Maiden Re North America . We assumed total gross unaffiliated reserves of $72.1 million for total assets of $70.4 million on a funds held basis and recorded a deferred charge asset of $1.7 million . Coca-Cola On August 1, 2018 , we entered into a reinsurance transaction with The Coca-Cola Company and its subsidiaries ("Coca-Cola"), pursuant to which we reinsured certain of Coca-Cola's retention and deductible risks under its subsidiaries' U.S. workers' compensation, auto liability, general liability and product liability insurance coverage. We assumed total gross reserves of $120.8 million for cash consideration of $103.6 million and recorded a deferred charge asset of $17.2 million . We transferred the cash consideration received of $103.6 million into a trust to support our obligations under the reinsurance agreement. Zurich Australia On February 23, 2018 , we entered into a reinsurance agreement with Zurich Australian Insurance Limited, a subsidiary of Zurich Insurance Group ("Zurich"), to reinsure its New South Wales Vehicle Compulsory Third Party ("CTP") insurance business. Under the agreement, which was effective as of January 1, 2018 , we assumed gross loss reserves of AUD$359.4 million ( $280.8 million ) in exchange for consideration of AUD$343.9 million ( $268.7 million ). We elected the fair value option for this reinsurance contract and recorded an initial fair value adjustment of AUD$15.5 million ( $12.1 million ) on the assumed gross loss reserves. Refer to Note 12 - "Fair Value Measurements" for a description of the fair value process and the assumptions made. Neon RITC Transaction On February 16, 2018, we completed a reinsurance-to-close (“RITC”) transaction with Neon Underwriting Limited ("Neon"), under which we reinsured to close the 2015 and prior underwriting years of account (comprising underwriting years 2008 to 2015) of Neon's Syndicate 2468, with effect from January 1, 2018. We assumed gross loss reserves of £403.9 million ( $546.3 million ) and net loss reserves of £342.1 million ( $462.6 million ) relating to the portfolio in exchange for consideration of £329.1 million ( $445.1 million ). We elected the fair value option for this reinsurance contract and recorded initial fair value adjustments of $20.6 million and $17.5 million on the gross and net loss reserves assumed, respectively. Refer to Note 12 - "Fair Value Measurements" for a description of the fair value process and the assumptions made. Novae RITC Transaction On January 29, 2018 , we completed an RITC transaction with AXIS Managing Agency Limited, under which we reinsured to close the 2015 and prior underwriting years of account of Novae Syndicate 2007 ("Novae"), with effect from January 1, 2018. We assumed gross loss reserves of £860.1 million ( $1,163.2 million ) and net loss reserves of £630.7 million ( $853.0 million ) relating to the portfolio in exchange for consideration of £594.1 million ( $803.5 million ) and recorded initial fair value adjustments of $67.5 million and $49.5 million on the gross and net loss reserves assumed, respectively. Refer to Note 12 - "Fair Value Measurements" for a description of the fair value process and the assumptions made. Allianz On December 28, 2017, we entered into a reinsurance agreement with Allianz to reinsure a portfolio of Allianz’s run-off business, effective December 31, 2017. Pursuant to the reinsurance agreement, we reinsured 50% of certain U.S. workers' compensation, asbestos, and toxic tort business originally held by San Francisco Reinsurance Company, an affiliate of Allianz, and in the process assumed net reinsurance reserves of $81.4 million . Affiliates of Allianz retained $81.4 million of reinsurance premium as funds withheld collateral for the obligations under the reinsurance agreement and we transferred $8.1 million to a reinsurance trust to further support our obligations. We also provide ongoing consulting services with respect to the entire $162.8 million portfolio, including the 50% share retained by affiliates of Allianz. RSA On February 7, 2017, we entered into an agreement to reinsure the U.K. employers' liability legacy business of RSA Insurance Group PLC ("RSA"). Pursuant to the transaction, our subsidiary assumed gross insurance reserves of £1,046.4 million ( $1,301.8 million ), relating to 2005 and prior year business. Net insurance reserves assumed were £927.5 million ( $1,153.9 million ) a nd the reinsurance premium received was £801.6 million ( $997.2 million ). We elected the fair value option for this reinsurance contract. The initial fair value adjustment on the gross reserves was $174.1 million , and on the net reserves was $156.7 million . Refer to Note 12 - "Fair Value Measurements" for a description of the fair value process and assumptions. In addition to the initial reinsurance transaction, which transferred the economics of the portfolio up to the policy's limits, we and RSA completed a portfolio transfer of the business under Part VII of the Financial Services and Markets Act 2000 on July 1, 2019, which provided legal finality for RSA's obligations. QBE On January 11, 2017, we closed a transaction to reinsure multi-line property and casualty business of QBE Insurance Group Limited ("QBE"). We assumed gross reinsurance reserves of approximately $1,019.0 million (net reserves of $447.0 million ) relating to the portfolio, which primarily includes workers' compensation, construction defect, and general liability discontinued lines of business. The reinsurance premium received was $403.8 million , comprised of $227.6 million in restricted cash and $176.2 million in funds held. We elected the fair value option for this reinsurance contract. The initial fair value adjustment was $180.0 million on the gross reserves and $43.2 million on the net reserves. Refer to Note 12 - "Fair Value Measurements" for a description of the fair value process and assumptions. In addition, we pledged a portion of the premium as collateral to a subsidiary of QBE, and we have provided additional collateral and a limited parental guarantee.

Divestitures, Held-For-Sale Bus

Divestitures, Held-For-Sale Businesses and Discontinued Operations	12 Months Ended
	Dec. 31, 2019
Discontinued Operations and Disposal Groups [Abstract]
Divestitures, Held-For-Sale Business and Discontinued Operations	5. DIVESTITURES, HELD-FOR-SALE BUSINESSES AND DISCONTINUED OPERATIONS Policy Benefits for Life Contracts held by Alpha Insurance On May 31, 2019, we completed the transfer of our remaining life assurance policies written by our wholly-owned subsidiary Alpha Insurance SA to a subsidiary of Monument Insurance Group Limited ("Monument"). Our life and annuities operations do not qualify for inclusion in our reportable segments and are therefore included within other activities. The related assets, as well as the results from these operations, were not significant to our consolidated operations and therefore were not classified as a discontinued operation. In addition, our transfer of these life assurance polices to Monument was not classified as a held-for-sale business transaction since the underlying contracts did not meet the definition of a business. We have an equity method investment in Monument, as described further in Note 21 - "Related Party Transactions" . Life assurance polices subjected us to mortality, longevity and morbidity risks and were accounted for as life and annuity premiums earned. Life benefit reserves were established using assumptions for investment yields, mortality, morbidity, lapse and expenses, including a provision for adverse deviation. We established and reviewed our life reserves regularly based upon cash flow projections. We established and maintained our life reinsurance reserves at a level that we estimated would, when taken together with future premium payments and investment income expected to be earned on associated premiums, be sufficient to support all future cash flow benefit obligations and third-party servicing obligations as they become payable. Policy benefits for life contracts as of December 31, 2018 were $105.1 million . Pavonia On December 29, 2017, we completed the sale of our subsidiary, Pavonia Holdings (US), Inc. (“Pavonia”), to Southland National Holdings, Inc. (“Southland”), a Delaware corporation and a subsidiary of Global Bankers Insurance Group, LLC. The aggregate purchase price was $120.0 million . We used the proceeds to make repayments under our revolving credit facility. Pavonia was a substantial portion of our previously reported Life and Annuities segment. Pavonia was classified as held-for-sale prior to its sale during 2017. The Pavonia business qualified as a discontinued operation. Net earnings from discontinued operations from Pavonia recorded in the consolidated statement of earnings were $11.0 million for the year ended December 31, 2017 . The change in cash of businesses held for sale on the consolidated cash flow statement from Pavonia was $118.3 million whilst under our ownership for the year ended December 31, 2017 . The cash, cash equivalents and restricted cash carried on the balance sheet of Pavonia on December 29, 2017, the date of disposal, were $135.1 million . A sale of one subsidiary, Pavonia Life Insurance Company of New York ("PLIC NY"), has not yet been agreed or completed. As of December 31, 2019 and 2018 , included within other assets and other liabilities on our consolidated balance sheet were amounts of $20.6 million and $11.7 million , and $24.0 million and $11.3 million , respectively, relating to PLIC NY. Laguna On August 29, 2017, we closed the previously-announced sale of our wholly-owned subsidiary Laguna Life DAC (“Laguna”) to a subsidiary of Monument, for a total consideration of €25.6 million (approximately $30.8 million ). We have an equity method investment in Monument, as described further in Note 21 - "Related Party Transactions" . Laguna was classified as held-for-sale during 2017 prior to its sale. Following the closing of the sale of Laguna, we recorded a loss on sale of $16.3 million for the year ended December 31, 2017, which was included in earnings from continuing operations before income taxes in our consolidated statement of earnings. This loss included a cumulative currency translation adjustment balance of $6.3 million , which was reclassified from accumulated other comprehensive income and included in earnings as a component of the loss on sale of Laguna during the year ended December 31, 2017, following the closing of the sale. Excluding the loss on sale, the net losses relating to Laguna for the year ended December 31, 2017 were $1.2 million . These amounts were not significant to our consolidated operations and therefore Laguna was not classified as a discontinued operation.

Investments

Investments	12 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
INVESTMENTS	6. INVESTMENTS We hold: (i) trading portfolios of fixed maturity investments, short-term investments and equities, carried at fair value; (ii) available-for-sale portfolios of fixed maturity and short-term investments, carried at fair value; (iii) other investments carried at fair value; (iv) equity method investments; and (v) funds held - directly managed. Fixed Maturity Investments Asset Types The fair values of the underlying asset types of our short-term investments and fixed maturity investments, classified as trading and available-for-sale, and the fixed maturity investments included within our funds held - directly managed balance were as follows as of December 31, 2019 and 2018 : 2019 Short-term investments, trading Short-term investments, available-for-sale Fixed maturities, trading Fixed maturities, available-for-sale Fixed maturities, funds held - directly managed Total U.S. government and agency $ — $ 111,583 $ 219,194 $ 298,729 $ 106,537 $ 736,043 U.K. government 24,411 1,069 122,012 14,280 — 161,772 Other government 21,958 387 575,018 84,760 20,734 702,857 Corporate 5,121 13,915 4,007,386 1,067,256 603,389 5,697,067 Municipal — 1,381 102,554 14,491 49,456 167,882 Residential mortgage-backed — — 258,412 127,219 86,205 471,836 Commercial mortgage-backed — — 571,129 98,557 230,343 900,029 Asset-backed — — 490,624 208,097 76,681 775,402 Total fixed maturity and short-term investments $ 51,490 $ 128,335 $ 6,346,329 $ 1,913,389 $ 1,173,345 $ 9,612,888 2018 Short-term investments, trading Fixed maturities, trading Fixed maturities, available-for-sale Fixed maturities, funds held - directly managed Total U.S. government and agency $ 45,885 $ 389,735 $ 573 $ 74,052 $ 510,245 U.K. government 2,275 298,356 — — 300,631 Other government 19,064 679,525 73,185 22,036 793,810 Corporate 44,900 4,081,793 75,359 637,788 4,839,840 Municipal — 73,856 2,480 53,929 130,265 Residential mortgage-backed — 682,962 12 90,583 773,557 Commercial mortgage-backed — 488,598 — 224,465 713,063 Asset-backed 1,992 553,968 — 80,521 636,481 Total fixed maturity and short-term investments $ 114,116 $ 7,248,793 $ 151,609 $ 1,183,374 $ 8,697,892 Included within residential and commercial mortgage-backed securities as of December 31, 2019 were securities issued by U.S. governmental agencies with a fair value of $356.9 million (as of December 31, 2018 : $656.6 million ). Included within corporate securities as of December 31, 2019 were senior secured loans of $31.4 million (as of December 31, 2018 : $20.4 million ). Contractual Maturities The contractual maturities of our short-term investments and fixed maturity investments, classified as trading and available-for-sale, and the fixed maturity investments included within our funds held - directly managed balance are shown below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call o r prepayment penalties. As of December 31, 2019 Amortized Cost Fair Value % of Total Fair Value One year or less $ 537,944 $ 536,156 5.6 % More than one year through two years 801,473 808,071 8.4 % More than two years through five years 2,175,547 2,212,834 23.0 % More than five years through ten years 2,108,172 2,198,505 22.9 % More than ten years 1,584,345 1,710,055 17.8 % Residential mortgage-backed 466,932 471,836 4.9 % Commercial mortgage-backed 882,603 900,029 9.4 % Asset-backed 779,279 775,402 8.0 % $ 9,336,295 $ 9,612,888 100.0 % Credit Ratings The following table sets forth the credit ratings of our short-term investments and fixed maturity investments, classified as trading and available-for-sale, and the fixed maturity investments included within our funds held - directly managed balance as of December 31, 2019 : Amortized Cost Fair Value % of Total AAA Rated AA Rated A Rated BBB Rated Non- Investment Grade Not Rated U.S. government and agency $ 730,396 $ 736,043 7.7 % $ 736,043 $ — $ — $ — $ — $ — U.K. government 155,261 161,772 1.7 % — 161,772 — — — — Other government 684,117 702,857 7.3 % 316,151 154,072 63,270 144,557 24,807 — Corporate 5,479,839 5,697,067 59.2 % 149,108 619,707 2,911,867 1,703,328 311,167 1,890 Municipal 157,868 167,882 1.7 % 16,381 77,291 50,938 23,272 — — Residential mortgage-backed 466,932 471,836 4.9 % 381,502 47,489 2,295 1,882 34,055 4,613 Commercial mortgage-backed 882,603 900,029 9.4 % 632,461 89,347 95,508 66,573 6,224 9,916 Asset-backed 779,279 775,402 8.1 % 378,116 89,418 174,118 117,275 15,694 781 Total $ 9,336,295 $ 9,612,888 100.0 % $ 2,609,762 $ 1,239,096 $ 3,297,996 $ 2,056,887 $ 391,947 $ 17,200 % of total fair value 27.1 % 12.9 % 34.3 % 21.4 % 4.1 % 0.2 % Unrealized Gains and Losses on Available-for-sale Fixed Maturity Investments The amortized cost and fair values of our fixed maturity investments classified as available-for-sale were as follows as of December 31, 2019 and 2018 : 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Non-OTTI Fair Value U.S. government and agency $ 410,842 $ 77 $ (607 ) $ 410,312 U.K. government 15,067 282 — 15,349 Other government 84,116 1,119 (88 ) 85,147 Corporate 1,081,713 4,026 (4,568 ) 1,081,171 Municipal 15,963 20 (111 ) 15,872 Residential mortgage-backed 127,704 240 (725 ) 127,219 Commercial mortgage-backed 98,928 38 (409 ) 98,557 Asset-backed 208,121 169 (193 ) 208,097 $ 2,042,454 $ 5,971 $ (6,701 ) $ 2,041,724 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Non-OTTI Fair Value U.S. government and agency $ 576 $ — $ (3 ) $ 573 Other government 72,811 1,219 (845 ) 73,185 Corporate 75,535 1,006 (1,182 ) 75,359 Municipal 2,499 — (19 ) 2,480 Residential mortgage-backed 12 — — 12 $ 151,433 $ 2,225 $ (2,049 ) $ 151,609 Gross Unrealized Losses on Available-for-sale Fixed Maturity Investments The following tables summarize our fixed maturity and short-term investments classified as available-for-sale in a gross unrealized loss position, as of December 31, 2019 and 2018 : 12 Months or Greater Less Than 12 Months Total 2019 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fixed maturity investments, at fair value U.S. government and agency $ — $ — $ 222,643 $ (607 ) $ 222,643 $ (607 ) Other government 1,080 (23 ) 37,796 (65 ) 38,876 (88 ) Corporate 2,754 (306 ) 461,772 (4,262 ) 464,526 (4,568 ) Municipal 128 — 12,046 (111 ) 12,174 (111 ) Residential mortgage-backed — — 65,992 (725 ) 65,992 (725 ) Commercial mortgage-backed — — 79,606 (409 ) 79,606 (409 ) Asset-backed — — 129,014 (193 ) 129,014 (193 ) Total fixed maturity and short-term investments $ 3,962 $ (329 ) $ 1,008,869 $ (6,372 ) $ 1,012,831 $ (6,701 ) 12 Months or Greater Less Than 12 Months Total 2018 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fixed maturity and short-term investments, at fair value U.S. government and agency $ 573 $ (3 ) $ — $ — $ 573 $ (3 ) Other government 7,351 (345 ) 11,000 (500 ) 18,351 (845 ) Corporate 11,888 (629 ) 25,227 (553 ) 37,115 (1,182 ) Municipal 1,783 (18 ) 283 (1 ) 2,066 (19 ) Residential mortgage-backed 12 — — — 12 — Total fixed maturity and short-term investments $ 21,607 $ (995 ) $ 36,510 $ (1,054 ) $ 58,117 $ (2,049 ) As of December 31, 2019 and 2018 , the number of securities classified as available-for-sale in an unrealized loss position was 563 and 88 , respectively. Of these securities, the number of securities that had been in an unrealized loss position for twelve months or longer was 12 and 42 , respectively. From October 1, 2019 we elected to use available-for-sale accounting for all new acquisitions and where permissible, as trading fixed maturity securities mature, we are reinvesting the proceeds into available-for-sale securities for the Non-Life Run-off and StarStone segments. Other-Than-Temporary Impairment on Available-for-sale Fixed Maturity Investments For the years ended December 31, 2019 , 2018 and 2017 , we did no t recognize any other-than-temporary impairment losses on our available-for-sale securities. We determined that no credit losses existed as of December 31, 2019 and 2018 . A description of our other-than-temporary impairment process is included in Note 2 - "Significant Accounting Policies" . There were no changes to our process in the years ended December 31, 2019 and 2018 . Equity Investments The following table summarizes our equity investments classified as trading as of December 31, 2019 and 2018 : 2019 2018 Publicly traded equity investments in common and preferred stocks $ 327,875 $ 138,415 Exchange-traded funds 133,047 — Privately held equity investments in common and preferred stocks 268,799 228,710 $ 729,721 $ 367,125 Equity investments include publicly traded common and preferred stocks, exchange-traded funds and privately held common and preferred stocks. Our publicly traded equity investments in common and preferred stocks predominantly trade on major exchanges and are managed by our external advisors. Our investments in exchange-traded funds trade on a major exchange. Our privately held equity investments in common and preferred stocks are direct investments in companies that we believe offer attractive risk adjusted returns and/or offer other strategic advantages. Each investment may have its own unique terms and conditions and there may be restrictions on disposals. The market for these investments is illiquid and there is no active market. Included within the above balance as of December 31, 2019 is an investment in the parent company of AmTrust Financial Services, Inc. ("AmTrust"), with a fair value of $240.1 million . Refer to Note 21 - "Related Party Transactions" Other Investments, at fair value The following table summarizes our other investments carried at fair value as of December 31, 2019 and 2018 : 2019 2018 Hedge funds $ 1,121,904 $ 852,584 Fixed income funds 481,039 403,858 Equity funds 410,149 333,681 Private equity funds 329,885 248,628 CLO equity funds 87,509 37,260 CLO equities 87,555 39,052 Private credit funds — 33,381 Others 6,379 9,313 $ 2,524,420 $ 1,957,757 The valuation of our other investments is described in Note 12 - "Fair Value Measurements" . Due to a lag in the valuations of certain funds reported by the managers, we may record changes in valuation with up to a three -month lag. We regularly review and discuss fund performance with the fund managers to corroborate the reasonableness of the reported net asset values and to assess whether any events have occurred within the lag period that would affect the valuation of the investments. The following is a description of the nature of each of these investment categories: • Hedge funds may invest in a wide range of instruments, including debt and equity securities, and utilize various sophisticated strategies to achieve their objectives. We invest in a mixture of fixed income, equity and multi-strategy hedge funds. • Fixed income funds comprise a number of positions in diversified fixed income funds that are managed by third-party managers. Underlying investments vary from high-grade corporate bonds to non-investment grade senior secured loans and bonds, but are generally invested in liquid fixed income markets. These funds have regularly published prices. • Equity funds invest in a diversified portfolio of U.S. and international publicly-traded equity securities. • Private equity funds invest primarily in the financial services industry. • CLO equity funds invest primarily in the equity tranches of term-financed securitizations of diversified pools of corporate bank loans. • CLO equities comprise investments in the equity tranches of term-financed securitizations of diversified pools of corporate bank loans. • Private credit funds invest in direct senior or collateralized loans. • Others comprise of various investments including a real estate debt fund that invests primarily in European commercial real estate equity, call options on equities and a fund that provides loans to educational institutions throughout the United States and its territories. The increase in our other investments carried at fair value between December 31, 2019 and December 31, 2018 was primarily attributable to unrealized gains of $441.6 million and net additional subscriptions of $214.3 million to CLO equity, CLO equity funds, fixed income funds and private equity funds. As of December 31, 2019 , we had unfunded commitments of $482.3 million to private equity funds. Certain of our other investments are subject to restrictions on redemptions and sales that are determined by the governing documents, which limits our ability to liquidate those investments. These restrictions may include lock-ups, redemption gates, restricted share classes or side pockets, restrictions on the frequency of redemption and notice periods. A gate is the ability to deny or delay a redemption request, whereas a side-pocket is a designated account for which the investor loses its redemption rights. Certain other investments may not have any restrictions governing their sale, but there is no active market and no guarantee that we will be able to execute a sale in a timely manner. In addition, even if certain other investments are not eligible for redemption or sales are restricted, we may still receive income distributions from those other investments. The table below details the estimated date by which proceeds would be received if we had provided notice of our intent to redeem or initiated a sales process as of December 31, 2019 : Less than 1 Year 1-2 years 2-3 years More than 3 years Not Eligible/ Restricted Total Redemption Frequency Hedge funds $ 343,005 $ 624,233 $ — $ 102,600 $ 52,066 $ 1,121,904 Monthly to Bi-annually Fixed income funds 477,935 — — — 3,104 481,039 Daily to Quarterly Equity funds 410,149 — — — — 410,149 Daily to Quarterly Private equity funds — — — 329,885 329,885 N/A CLO equity funds 60,735 — 26,774 — — 87,509 Quarterly to Bi-annually CLO equities 87,555 — — — — 87,555 N/A Other 34 — — — 6,345 6,379 N/A $ 1,379,413 $ 624,233 $ 26,774 $ 102,600 $ 391,400 $ 2,524,420 Equity Method Investments The table below shows our equity method investments as of December 31, 2019 and 2018 : 2019 2018 Investment Ownership % Carrying Value Investment Ownership % Carrying Value Enhanzed Re $ 154,050 47.4 % $ 182,856 $ 94,800 47.4 % $ 94,800 Citco 50,000 31.9 % 51,742 50,000 31.9 % 50,812 Monument 26,600 26.6 % 60,598 26,600 26.6 % 42,193 Clear Spring 11,210 20.0 % $ 10,645 11,210 20.0 % 10,070 Other 24,963 ~30% 20,436 15,250 ~30% 6,632 $ 266,823 $ 326,277 $ 197,860 $ 204,507 Refer to Note 21 - "Related Party Transactions" for further information regarding our investments in Clear Spring, Citco, Monument and Enhanzed Re. As of December 31, 2019 , we had unfunded commitments of $93.1 million related to equity method investments. Funds Held Funds Held - Directly Managed Funds held - directly managed, where we receive the underlying return on the investment portfolio, are carried at fair value, either because we elected the fair value option at the inception of the reinsurance contract, or because it represents the aggregate of funds held at amortized cost and the fair value of an embedded derivative. The embedded derivative relates to our contractual right to receive the return on the underlying investment portfolio supporting the reinsurance contract. We include the estimated fair value of these embedded derivatives in the consolidated balance sheets with the host contract in order to reflect the expected settlement of these features with the host contract. The change in the fair value of the embedded derivative is included in net unrealized gains (losses). The following table summarizes the components of the funds held - directly managed as of December 31, 2019 and 2018 : 2019 2018 Fixed maturity investments, trading $ 1,173,345 $ 1,183,374 Other assets 14,207 14,780 $ 1,187,552 $ 1,198,154 The following table summarizes the fixed maturity investment components of funds held - directly managed as of December 31, 2019 and 2018 : 2019 2018 Funds held - Directly Managed - Fair Value Option Funds held - Directly Managed - Variable Return Total Funds held - Directly Managed - Fair Value Option Funds held - Directly Managed - Variable Return Total Fixed maturity investments, at amortized cost $ 185,859 $ 940,194 $ 1,126,053 $ 179,670 $ 1,044,377 $ 1,224,047 Net unrealized gains (losses): Change in fair value - fair value option accounting 5,438 — 5,438 (2,733 ) — (2,733 ) Change in fair value - embedded derivative accounting — 41,854 41,854 — (37,940 ) (37,940 ) Fixed maturity investments within funds held - directly managed, at fair value $ 191,297 $ 982,048 $ 1,173,345 $ 176,937 $ 1,006,437 $ 1,183,374 Refer to the sections above for details of the fixed maturity investments within our funds held - directly managed portfolios. Funds Held by Reinsured Companies Funds held by reinsured companies, where we received a fixed crediting rate, are carried at cost on our consolidated balance sheets. As of December 31, 2019 and 2018 , we had funds held by reinsured companies of $408.7 million and $321.3 million , respectively. Net Investment Income Major categories of net investment income for the years ended December 31, 2019 , 2018 and 2017 are summarized as follows: 2019 2018 2017 Fixed maturity investments $ 233,310 $ 189,000 $ 144,367 Short-term investments and cash and cash equivalents 16,607 12,117 9,314 Funds held 19,981 10,041 601 Funds held – directly managed 38,173 37,623 32,479 Investment income from fixed maturities and cash and cash equivalents 308,071 248,781 186,761 Equity investments 16,671 5,397 4,355 Other investments 11,792 19,703 14,337 Life settlements and other — 6,511 14,370 Investment income from equities and other investments 28,463 31,611 33,062 Gross investment income 336,534 280,392 219,823 Investment expenses (15,258 ) (9,721 ) (11,034 ) Net investment income $ 321,276 $ 270,671 $ 208,789 Net Realized and Unrealized Gains (Losses) Components of net realized and unrealized gains (losses) for the years ended December 31, 2019 , 2018 and 2017 were as follows: 2019 2018 2017 Net realized gains (losses) on sale: Gross realized gains on fixed maturity securities, available-for-sale securities (1) $ 4,856 $ 27 $ 616 Gross realized losses on fixed maturity securities, available-for-sale securities (1) (962 ) (90 ) (125 ) Net realized gains (losses) on fixed maturity securities, trading 91,313 (27,646 ) 4,695 Net realized gains (losses) on fixed maturity securities in funds held - directly managed portfolios 1,495 (3,940 ) (4,219 ) Net realized gains (losses) on equity investments, trading (374 ) 4,016 701 Total net realized gains (losses) on sale 96,328 (27,633 ) 1,668 Net unrealized gains (losses): Fixed maturity securities, trading 349,975 (165,187 ) 35,878 Fixed maturity securities in funds held - directly managed portfolios 88,053 (46,257 ) 33,902 Equity investments, trading 55,359 (9,831 ) 16,498 Other investments 441,636 (163,976 ) 102,388 Total net unrealized gains (losses) 935,023 (385,251 ) 188,666 Net realized and unrealized gains (losses) $ 1,031,351 $ (412,884 ) $ 190,334 (1) The gross realized gains and losses on available-for-sale investments included in the table above resulted from sales of $310.4 million , $11.4 million and $40.8 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. Restricted Assets We utilize trust accounts to collateralize business with our insurance and reinsurance counterparties. We are also required to maintain investments and cash and cash equivalents on deposit with regulatory authorities and Lloyd's to support our insurance and reinsurance operations. The investments and cash and cash equivalents on deposit are available to settle insurance and reinsurance liabilities. Collateral generally takes the form of assets held in trust, letters of credit or funds held. The assets used as collateral are primarily highly rated fixed maturity securities. The carrying value of our restricted assets, including restricted cash of $352.7 million and $380.5 million , as of December 31, 2019 and 2018 , respectively, was as follows: 2019 2018 Collateral in trust for third party agreements $ 4,104,093 $ 4,336,752 Assets on deposit with regulatory authorities 445,626 579,048 Collateral for secured letter of credit facilities 133,238 127,841 Funds at Lloyd's (1) 639,316 354,589 $ 5,322,273 $ 5,398,230 (1) Our businesses include three Lloyd's syndicates. Lloyd's determines the required capital principally through the annual business plan of each syndicate. This capital is referred to as "Funds at Lloyd's" and will be drawn upon in the event that a syndicate has a loss that cannot be funded from other sources. We also utilize unsecured letters of credit for Funds at Lloyd's, as described in Note 15 - "Debt Obligations and Credit Facilities" . Funds at Lloyd's increased primarily due to reinsurance to close ("RITC") transactions, during 2019 .

Derivatives and Hedging Instrum

Derivatives and Hedging Instruments	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Instruments	7. DERIVATIVES AND HEDGING INSTRUMENTS Foreign Currency Hedging of Net Investments in Foreign Operations We use foreign currency forward exchange rate contracts in qualifying hedging relationships to hedge the foreign currency exchange rate risk associated with certain of our net investments in foreign operations. As of December 31, 2019 and 2018 , we had forward foreign currency contracts in place which we had designated as hedges of our net investments in foreign operations. The following table presents the gross notional amounts and the estimated fair values recorded within other assets and liabilities related to our qualifying foreign currency forward exchange rate contracts as of December 31, 2019 and 2018 : 2019 2018 Fair Value Fair Value Gross Notional Amount Assets Liabilities Gross Notional Amount Assets Liabilities Foreign exchange forward - AUD $ 64,620 $ 52 $ 2,033 $ 42,258 $ 1,377 $ — Foreign exchange forward - EUR 112,284 246 1,635 66,422 238 300 Foreign exchange forward - GBP 318,387 344 7,784 — — — Total qualifying hedges $ 495,291 $ 642 $ 11,452 $ 108,680 $ 1,615 $ 300 The following table presents the amounts of the net gains and losses deferred in the cumulative translation adjustment ("CTA") account, which is a component of accumulated other comprehensive income (loss) ("AOCI"), in shareholders' equity, relating to our foreign currency forward exchange rate contracts for the years ended December 31, 2019 , 2018 and 2017 : Amount of Gains (Losses) Deferred in AOCI 2019 2018 2017 Foreign exchange forward - AUD $ (722 ) $ 3,438 $ (1,247 ) Foreign exchange forward - EUR 1,817 1,000 — Foreign exchange forward - GBP (16,423 ) — — Total qualifying hedges $ (15,328 ) $ 4,438 $ (1,247 ) Non-derivative Hedging Instruments of Net Investments in Foreign Operations From time to time, we may also use non-derivative instruments such as foreign currency denominated borrowings under our credit facilities to hedge certain of our net investments in foreign operations in designated qualifying non-derivative hedging arrangements. While there were no foreign currency denominated borrowings outstanding under our credit facilities as of December 31, 2019 and 2018, the following table presents the amounts of the net gains and losses deferred in the CTA account in AOCI relating to these qualifying non-derivative hedging instruments for the years ended December 31, 2018 and 2017: Amount of Gains (Losses) Deferred in AOCI 2018 2017 Net gains (losses) on qualifying non-derivative hedges 3,144 (9,375 ) Derivatives Not Designated or Not Qualifying as Hedging Instruments From time to time, we may also utilize foreign currency forward contracts as part of our overall foreign currency risk management strategy or to obtain exposure to a particular financial market, as well as for yield enhancement in non-qualifying hedging relationships. We may also utilize equity call option instruments either to obtain exposure to a particular equity instrument or for yield enhancement in non-qualifying hedging relationships. Foreign Currency Forward Contracts The following table presents the gross notional amounts and the estimated fair values recorded within other assets and liabilities as of December 31, 2019 and 2018 and the gains and losses during the years ended December 31, 2019 and 2018 , related to our non-qualifying foreign currency forward exchange rate hedging relationships : December 31, 2019 2019 Fair Value Gross Notional Amount Assets Liabilities Gains (losses) on non-qualifying hedges charged to earnings Foreign exchange forward - AUD $ 913 $ 839 $ 892 $ 1,523 Foreign exchange forward - CAD 66,266 10 1,482 (2,079 ) Foreign exchange forward - EUR 74,444 507 1,440 1,759 Foreign exchange forward - GBP 11,940 13 292 12,004 Total non-qualifying hedges $ 153,563 $ 1,369 $ 4,106 $ 13,207 December 31, 2018 2018 Fair Value Gross Notional Amount Assets Liabilities Gains (losses) on non-qualifying hedges charged to earnings Foreign exchange forward - AUD $ 45,427 $ 1,952 $ 310 $ 4,958 Foreign exchange forward - CAD 55,050 1,441 — 9,311 Foreign exchange forward - EUR 54,282 139 301 2,296 Foreign exchange forward - GBP 256,959 1,554 72 15,078 Total non-qualifying hedges $ 411,718 $ 5,086 $ 683 $ 31,643 Investments in Call Options on Equities During the years ended December 31, 2019 and 2018, we recorded unrealized gains of approximately $0.5 million and unrealized losses of $9.4 million respectively, within net earnings, on the call options on equities which we purchased in 2018 at a cost of $10.0 million . These call options on equities had a fair value of less than $0.1 million and $0.6 million as of December 31, 2019 and 2018, respectively. Other Derivatives In 2019 we entered into a forward interest rate swap, with a notional amount of AUD$120.0 million , to partially mitigate the risk associated with declining interest rates until the receipt of the assets related to the Munich Re transaction, as discussed in Note 3 - "Significant New Business" , which is expected to close in 2020. The carrying value of the forward interest rate swap, recorded in other liabilities, was $0.3 million as of December 31, 2019. We recorded unrealized losses in net earnings of $0.3 million on the instrument for the year ended December 31, 2019.

Reinsurance Balances Recoverabl

Reinsurance Balances Recoverable on Paid and Unpaid Losses	12 Months Ended
	Dec. 31, 2019
Insurance [Abstract]
Reinsurance Balances Recoverable on Paid and Unpaid Losses	$1 million 551,636 7,761 233,871 793,268 33.4 % 364,098 12,091 220,123 596,312 29.4 % Other reinsurers < $1 million 19,243 545 2,502 22,290 0.9 % 16,211 1,182 3,448 20,841 1.0 % Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 100.0 % $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 100.0 % December 31, 2019 December 31, 2018 Information regarding top ten reinsurers: Number of top 10 reinsurers rated A- or better 8 7 Number of top 10 non-rated reinsurers (1) 2 3 Recoverables rated A- or better in top 10 $ 1,292,207 $ 1,096,272 Collaterized non-rated reinsurers recoverables in top 10 (1) 272,125 316,238 $ 1,564,332 $ 1,412,510 Single reinsurers that represent 10% or more of total reinsurance balance recoverables as of December 31, 2019: Hannover Ruck SE (2) $ 261,295 $ 279,723 Lloyd's Syndicates (3) $ 411,030 $ 334,509 (1) For the two non-rated reinsurers as of December 31, 2019 and three non-rated reinsurers as at December 31, 2018 , we hold security in the form of pledged assets in trust or letters of credit issued to us in the full amount of the recoverable. (2) Hannover Ruck SE is rated AA- by Standard & Poor’s and A+ by A.M. Best. (3) Lloyd's Syndicates are rated A+ by Standard & Poor's and A by A.M. Best. Provisions for Uncollectible Reinsurance Balances Recoverable on Paid and Unpaid Losses We evaluate and monitor concentration of credit risk among our reinsurers. Provisions are made for amounts considered potentially uncollectible. The following table shows our reinsurance balances recoverable on paid and unpaid losses by rating of reinsurer and our provisions for uncollectible reinsurance balances recoverable on paid and unpaid losses ("provisions for bad debt") as of December 31, 2019 and 2018 . The majority of the provisions for bad debt relate to the Non-life Run-off segment. 2019 2018 Gross Provisions for Bad Debt Net Provisions as a Gross Provisions for Bad Debt Net Provisions as a Reinsurers rated A- or above $ 1,904,268 $ 43,427 $ 1,860,841 2.3 % $ 1,612,464 $ 51,519 $ 1,560,945 3.2 % Reinsurers rated below A-, secured 487,608 — 487,608 — % 430,852 — 430,852 — % Reinsurers rated below A-, unsecured 135,653 104,212 31,441 76.8 % 143,079 105,213 37,866 73.5 % Total $ 2,527,529 $ 147,639 $ 2,379,890 5.8 % $ 2,186,395 $ 156,732 $ 2,029,663 7.2 % 13. PREMIUMS WRITTEN AND EARNED The following tables provide a summary of net premiums written and earned for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Premiums Written Premiums Earned Premiums Written Premiums Earned Premiums Written Premiums Earned Non-life Run-off Gross $ (25,069 ) $ 197,009 $ (8,910 ) $ 25,230 $ 14,102 $ 23,950 Ceded (269 ) (28,513 ) (307 ) (15,803 ) (7,620 ) (9,788 ) Net $ (25,338 ) $ 168,496 $ (9,217 ) $ 9,427 $ 6,482 $ 14,162 Atrium Gross $ 192,373 $ 182,678 $ 171,494 $ 164,428 $ 153,472 $ 152,278 Ceded (20,017 ) (18,619 ) (18,006 ) (18,113 ) (19,258 ) (17,531 ) Net $ 172,356 $ 164,059 $ 153,488 $ 146,315 $ 134,214 $ 134,747 StarStone Gross $ 917,555 $ 1,021,827 $ 1,121,135 $ 1,010,816 $ 895,160 $ 865,159 Ceded (182,126 ) (219,901 ) (315,573 ) (295,857 ) (430,259 ) (405,756 ) Net $ 735,429 $ 801,926 $ 805,562 $ 714,959 $ 464,901 $ 459,403 Other Gross $ 18,534 $ 20,544 $ 32,378 $ 25,237 $ 5,719 $ 5,900 Ceded (22 ) (164 ) (311 ) (363 ) (926 ) (1,091 ) Net $ 18,512 $ 20,380 $ 32,067 $ 24,874 $ 4,793 $ 4,809 Total Gross $ 1,103,393 $ 1,422,058 $ 1,316,097 $ 1,225,711 $ 1,068,453 $ 1,047,287 Ceded (202,434 ) (267,197 ) (334,197 ) (330,136 ) (458,063 ) (434,166 ) Net $ 900,959 $ 1,154,861 $ 981,900 $ 895,575 $ 610,390 $ 613,121 Gross premiums written for the year ended December 31, 2019 and 2018 were $1,103.4 million and $1,316.1 million , respectively, a decrease of $212.7 million . The decrease was primarily due to a decrease in gross written premiums in our StarStone segment due to our strategy to exit certain lines of business, and reductions in gross written premiums in our Non-life Run-off segment due to unearned premium acquired in various transactions." id="sjs-B4">8. REINSURANCE BALANCES RECOVERABLE ON PAID AND UNPAID LOSSES The following table provides the total reinsurance balances recoverable on paid and unpaid losses as of December 31, 2019 and 2018 : 2019 Non-life Run-off Atrium StarStone Total Recoverable from reinsurers on unpaid: Outstanding losses $ 972,293 $ 9,011 $ 328,009 $ 1,309,313 IBNR 673,059 19,286 211,404 903,749 Fair value adjustments - acquired companies (13,652 ) 519 (2,122 ) (15,255 ) Fair value adjustments - fair value option (88,086 ) — — (88,086 ) Total reinsurance reserves recoverable 1,543,614 28,816 537,291 2,109,721 Paid losses recoverable 181,375 1,541 87,253 270,169 Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 Reconciliation to Consolidated Balance Sheet: Reinsurance balances recoverable on paid and unpaid losses $ 1,029,471 $ 30,357 $ 624,544 $ 1,684,372 Reinsurance balances recoverable on paid and unpaid losses - fair value option 695,518 — — 695,518 Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 2018 Non-life Run-off Atrium StarStone Total Recoverable from reinsurers on unpaid: Outstanding losses $ 901,772 $ 18,891 $ 263,065 $ 1,183,728 IBNR 609,434 19,247 201,784 830,465 Fair value adjustments - acquired companies (14,344 ) 630 (1,899 ) (15,613 ) Fair value adjustments - fair value option (130,739 ) — — (130,739 ) Total reinsurance reserves recoverable 1,366,123 38,768 462,950 1,867,841 Paid losses recoverable 138,265 (256 ) 23,813 161,822 Total $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 Reconciliation to Consolidated Balance Sheet: Reinsurance balances recoverable on paid and unpaid losses $ 764,797 $ 38,512 $ 486,763 $ 1,290,072 Reinsurance balances recoverable on paid and unpaid losses - fair value option 739,591 — — 739,591 Total $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 Our insurance and reinsurance run-off subsidiaries and assumed portfolios, prior to acquisition, used retrocessional agreements to reduce their exposure to the risk of insurance and reinsurance assumed. On an annual basis, both Atrium and StarStone purchase a tailored outwards reinsurance program designed to manage their risk profiles. The majority of Atrium’s and StarStone's third-party reinsurance cover is with highly rated reinsurers or is collateralized by pledged assets or letters of credit. The fair value adjustments, determined on acquisition of insurance and reinsurance subsidiaries, are based on the estimated timing of loss and LAE recoveries and an assumed interest rate equivalent to a risk free rate for securities with similar duration to the acquired reinsurance balances recoverable on paid and unpaid losses plus a spread to reflect credit risk, and are amortized over the estimated recovery period, as adjusted for accelerations in timing of payments as a result of commutation settlements. The determination of the fair value adjustments on the retroactive reinsurance contracts for which we have elected the fair value option is described in Note 12 - "Fair Value Measurements" . As of December 31, 2019 and 2018 , we had reinsurance balances recoverable on paid and unpaid losses of approximately $2,379.9 million and $2,029.7 million , respectively. The increase of $350.2 million in reinsurance balances recoverable on paid and unpaid losses was primarily due to the AmTrust RITC and Zurich reinsurance transactions, which closed during the first and fourth quarters of 2019, respectively, and reserve increases in StarStone and our non-life run-off segment, offset by commutations and cash collections made during the year ended December 31, 2019 . Top Ten Reinsurers December 31, 2019 December 31, 2018 Non-life Atrium StarStone Total % of Non-life Atrium StarStone Total % of Top ten reinsurers $ 1,154,110 $ 22,051 $ 388,171 $ 1,564,332 65.7 % $ 1,124,079 $ 25,239 $ 263,192 $ 1,412,510 69.6 % Other reinsurers > $1 million 551,636 7,761 233,871 793,268 33.4 % 364,098 12,091 220,123 596,312 29.4 % Other reinsurers < $1 million 19,243 545 2,502 22,290 0.9 % 16,211 1,182 3,448 20,841 1.0 % Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 100.0 % $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 100.0 % December 31, 2019 December 31, 2018 Information regarding top ten reinsurers: Number of top 10 reinsurers rated A- or better 8 7 Number of top 10 non-rated reinsurers (1) 2 3 Recoverables rated A- or better in top 10 $ 1,292,207 $ 1,096,272 Collaterized non-rated reinsurers recoverables in top 10 (1) 272,125 316,238 $ 1,564,332 $ 1,412,510 Single reinsurers that represent 10% or more of total reinsurance balance recoverables as of December 31, 2019: Hannover Ruck SE (2) $ 261,295 $ 279,723 Lloyd's Syndicates (3) $ 411,030 $ 334,509 (1) For the two non-rated reinsurers as of December 31, 2019 and three non-rated reinsurers as at December 31, 2018 , we hold security in the form of pledged assets in trust or letters of credit issued to us in the full amount of the recoverable. (2) Hannover Ruck SE is rated AA- by Standard & Poor’s and A+ by A.M. Best. (3) Lloyd's Syndicates are rated A+ by Standard & Poor's and A by A.M. Best. Provisions for Uncollectible Reinsurance Balances Recoverable on Paid and Unpaid Losses We evaluate and monitor concentration of credit risk among our reinsurers. Provisions are made for amounts considered potentially uncollectible. The following table shows our reinsurance balances recoverable on paid and unpaid losses by rating of reinsurer and our provisions for uncollectible reinsurance balances recoverable on paid and unpaid losses ("provisions for bad debt") as of December 31, 2019 and 2018 . The majority of the provisions for bad debt relate to the Non-life Run-off segment. 2019 2018 Gross Provisions for Bad Debt Net Provisions as a Gross Provisions for Bad Debt Net Provisions as a Reinsurers rated A- or above $ 1,904,268 $ 43,427 $ 1,860,841 2.3 % $ 1,612,464 $ 51,519 $ 1,560,945 3.2 % Reinsurers rated below A-, secured 487,608 — 487,608 — % 430,852 — 430,852 — % Reinsurers rated below A-, unsecured 135,653 104,212 31,441 76.8 % 143,079 105,213 37,866 73.5 % Total $ 2,527,529 $ 147,639 $ 2,379,890 5.8 % $ 2,186,395 $ 156,732 $ 2,029,663 7.2 % 13. PREMIUMS WRITTEN AND EARNED The following tables provide a summary of net premiums written and earned for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Premiums Written Premiums Earned Premiums Written Premiums Earned Premiums Written Premiums Earned Non-life Run-off Gross $ (25,069 ) $ 197,009 $ (8,910 ) $ 25,230 $ 14,102 $ 23,950 Ceded (269 ) (28,513 ) (307 ) (15,803 ) (7,620 ) (9,788 ) Net $ (25,338 ) $ 168,496 $ (9,217 ) $ 9,427 $ 6,482 $ 14,162 Atrium Gross $ 192,373 $ 182,678 $ 171,494 $ 164,428 $ 153,472 $ 152,278 Ceded (20,017 ) (18,619 ) (18,006 ) (18,113 ) (19,258 ) (17,531 ) Net $ 172,356 $ 164,059 $ 153,488 $ 146,315 $ 134,214 $ 134,747 StarStone Gross $ 917,555 $ 1,021,827 $ 1,121,135 $ 1,010,816 $ 895,160 $ 865,159 Ceded (182,126 ) (219,901 ) (315,573 ) (295,857 ) (430,259 ) (405,756 ) Net $ 735,429 $ 801,926 $ 805,562 $ 714,959 $ 464,901 $ 459,403 Other Gross $ 18,534 $ 20,544 $ 32,378 $ 25,237 $ 5,719 $ 5,900 Ceded (22 ) (164 ) (311 ) (363 ) (926 ) (1,091 ) Net $ 18,512 $ 20,380 $ 32,067 $ 24,874 $ 4,793 $ 4,809 Total Gross $ 1,103,393 $ 1,422,058 $ 1,316,097 $ 1,225,711 $ 1,068,453 $ 1,047,287 Ceded (202,434 ) (267,197 ) (334,197 ) (330,136 ) (458,063 ) (434,166 ) Net $ 900,959 $ 1,154,861 $ 981,900 $ 895,575 $ 610,390 $ 613,121 Gross premiums written for the year ended December 31, 2019 and 2018 were $1,103.4 million and $1,316.1 million , respectively, a decrease of $212.7 million . The decrease was primarily due to a decrease in gross written premiums in our StarStone segment due to our strategy to exit certain lines of business, and reductions in gross written premiums in our Non-life Run-off segment due to unearned premium acquired in various transactions.

Deferred Charge Assets

Deferred Charge Assets	12 Months Ended
	Dec. 31, 2019
Insurance [Abstract]
Deferred Charge Assets	9. DEFERRED CHARGE ASSETS Deferred charge assets relate to retroactive reinsurance policies providing indemnification of losses and LAE with respect to past loss events in the Non-life Run-off segment. For insurance and reinsurance contracts for which we do not elect the fair value option, a deferred charge asset is recorded for the excess, if any, of the estimated ultimate losses payable over the premiums received at the initial measurement. The premium consideration that we charge the ceding companies may be lower than the undiscounted estimated ultimate losses payable due to the time value of money. After receiving the premium consideration in full from our cedents at the inception of the contract, we invest the premium received over an extended period of time thereby generating investment income. We expect to generate profits from these retroactive reinsurance policies when taking into account the premium received and expected investment income, less contractual obligations and expenses. Further information on deferred charge assets recorded during the years ended December 31, 2019 , 2018 and 2017 is included in Note 4 - "Significant New Business" . Deferred charge assets are included in other assets on our consolidated balance sheets. The following table presents a reconciliation of the deferred charge assets for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Beginning carrying value $ 86,585 $ 80,192 $ 94,551 Recorded during the year 224,504 20,174 — Amortization (38,627 ) (13,781 ) (14,359 ) Ending carrying value $ 272,462 $ 86,585 $ 80,192 Deferred charge assets are amortized over the estimated claim payment period of the related contract with the periodic amortization reflected in earnings as a component of losses and LAE. Deferred charge assets amortization is adjusted at each reporting period to reflect new estimates of the amount and timing of remaining loss payments. Changes in the estimated amount and the timing of payments of unpaid losses may have an effect on the unamortized deferred charge assets and the amount of periodic amortization. When liabilities for losses and LAE are commuted or bought back, they are removed from the estimates for the remaining loss payments, and this will generally result in an acceleration of the amortization of the deferred charge assets. Deferred charge assets are assessed at each reporting period for impairment. If the asset is determined to be impaired, it is written down in the period in which the determination is made. For the year ended December 31, 2019 , we completed our assessment for impairment of deferred charge assets and concluded that there had been $nil impairment of our carried deferred charge assets amount.

Losses and Loss Adjustment Expe

Losses and Loss Adjustment Expenses	12 Months Ended
	Dec. 31, 2019
Insurance [Abstract]
Losses and Loss Adjustment Expenses	10. LOSSES AND LOSS ADJUSTMENT EXPENSES The liability for losses and loss adjustment expenses ("LAE"), also referred to as loss reserves, represents our gross estimates before reinsurance for unpaid reported losses and losses that have been incurred but not reported ("IBNR") for our Non-life Run-off, Atrium and StarStone segments using a variety of actuarial methods. We recognize an asset for the portion of the liability that we expect to recover from reinsurers. LAE reserves include allocated loss adjustment expenses ("ALAE"), and unallocated loss adjustment expenses ("ULAE"). ALAE are linked to the settlement of an individual claim or loss, whereas ULAE are based on our estimates of future costs to administer the claims. The following table summarizes the liability for losses and LAE by segment and for our other activities as of December 31, 2019 and 2018 : 2019 Non-life Run-off Atrium StarStone Other Total Outstanding losses $ 4,407,082 $ 89,141 $ 888,794 $ 9,512 $ 5,394,529 IBNR 3,945,407 136,543 962,353 13,565 5,057,868 Fair value adjustments - acquired companies (170,689 ) 3,700 (522 ) — (167,511 ) Fair value adjustments - fair value option (217,933 ) — — — (217,933 ) ULAE 331,494 2,288 28,503 — 362,285 Total $ 8,295,361 $ 231,672 $ 1,879,128 $ 23,077 $ 10,429,238 Reconciliation to Consolidated Balance Sheet: Losses and loss adjustment expenses $ 5,674,239 $ 231,672 $ 1,879,128 $ 23,077 $ 7,808,116 Losses and loss adjustment expenses, at fair value 2,621,122 — — — 2,621,122 Total $ 8,295,361 $ 231,672 $ 1,879,128 $ 23,077 $ 10,429,238 2018 Non-life Atrium StarStone Other Total Outstanding losses $ 4,271,769 $ 94,885 $ 796,194 $ 6,052 $ 5,168,900 IBNR 3,527,767 140,521 787,894 12,809 4,468,991 Fair value adjustments- acquired companies (217,527 ) 3,476 (467 ) — (214,518 ) Fair value adjustments - fair value option (374,752 ) — — — (374,752 ) ULAE 333,405 2,402 25,076 — 360,883 Total $ 7,540,662 $ 241,284 $ 1,608,697 $ 18,861 $ 9,409,504 Reconciliation to Consolidated Balance Sheet: Losses and loss adjustment expenses $ 4,666,607 $ 241,284 $ 1,608,697 $ 18,861 $ 6,535,449 Losses and loss adjustment expenses, at fair value 2,874,055 — — — 2,874,055 Total $ 7,540,662 $ 241,284 $ 1,608,697 $ 18,861 $ 9,409,504 The overall increase in the liability for losses and LAE between December 31, 2018 and December 31, 2019 was primarily attributable to the assumed reinsurance agreements with Zurich, Maiden Re Bermuda, Amerisure and AmTrust, as described in Note 4 - "Significant New Business" in our Non-life Run-off segment. The table below provides a consolidated reconciliation of the beginning and ending liability for losses and LAE for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Balance as at January 1 $ 9,409,504 $ 7,398,088 $ 5,987,867 Less: reinsurance reserves recoverable 1,867,841 1,870,033 1,388,193 Less: deferred charge assets on retroactive reinsurance 86,585 80,192 94,551 Net balance as at January 1 7,455,078 5,447,863 4,505,123 Net incurred losses and LAE: Current period 823,658 689,782 437,853 Prior periods 48,917 (235,757 ) (244,302 ) Total net incurred losses and LAE 872,575 454,025 193,551 Net paid losses: Current period (200,264 ) (189,560 ) (82,273 ) Prior periods (1,669,004 ) (1,194,985 ) (862,921 ) Total net paid losses (1,869,268 ) (1,384,545 ) (945,194 ) Effect of exchange rate movement 48,695 (145,243 ) 158,429 Acquired on purchase of subsidiaries 686 1,310,874 10,251 Assumed business 1,586,307 1,772,104 1,525,703 Ceded business (47,018 ) — — Net balance as at December 31 8,047,055 7,455,078 5,447,863 Plus: reinsurance reserves recoverable 2,109,721 1,867,841 1,870,033 Plus: deferred charge assets on retroactive reinsurance 272,462 86,585 80,192 Balance as at December 31 $ 10,429,238 $ 9,409,504 $ 7,398,088 The tables below provide the components of net incurred losses and LAE by segment and for our other activities for the years ended December 31, 2019 , 2018 and 2017 : 2019 Non-life Atrium StarStone Other Total Net losses paid $ 1,247,624 $ 78,189 $ 531,633 $ 11,822 $ 1,869,268 Net change in case and LAE reserves (530,891 ) 3,534 25,967 3,460 (497,930 ) Net change in IBNR reserves (813,582 ) (4,782 ) 166,427 756 (651,181 ) Increase (reduction) in estimates of net ultimate losses (96,849 ) 76,941 724,027 16,038 720,157 Increase (reduction) in provisions for unallocated LAE (57,404 ) — 3,441 — (53,963 ) Amortization of deferred charge assets 38,627 — — — 38,627 Amortization of fair value adjustments 50,070 335 168 — 50,573 Changes in fair value - fair value option 117,181 — — — 117,181 Net incurred losses and LAE $ 51,625 $ 77,276 $ 727,636 $ 16,038 $ 872,575 2018 Non-life Run-off Atrium StarStone Other Total Net losses paid $ 838,817 $ 64,506 $ 477,130 $ 4,092 $ 1,384,545 Net change in case and LAE reserves (547,420 ) 6,331 75,887 4,808 (460,394 ) Net change in IBNR reserves (565,385 ) 4,091 113,879 7,999 (439,416 ) Increase (reduction) in estimates of net ultimate losses (273,988 ) 74,928 666,896 16,899 484,735 Increase (reduction) in provisions for unallocated LAE (65,401 ) — 6,753 — (58,648 ) Amortization of deferred charge assets 13,781 — — — 13,781 Amortization of fair value adjustments 12,877 (5,118 ) (266 ) — 7,493 Changes in fair value - fair value option 6,664 — — — 6,664 Net incurred losses and LAE $ (306,067 ) $ 69,810 $ 673,383 $ 16,899 $ 454,025 2017 Non-life Atrium StarStone Total Net losses paid $ 581,723 $ 55,678 $ 307,793 $ 945,194 Net change in case and LAE reserves (381,053 ) 8,338 31,685 (341,030 ) Net change in IBNR reserves (390,727 ) 7,679 (23,540 ) (406,588 ) Increase (reduction) in estimates of net ultimate losses (190,057 ) 71,695 315,938 197,576 Increase (reduction) in provisions for bad debt (1,536 ) 159 — (1,377 ) Increase (reduction) in provisions for unallocated LAE (53,810 ) 285 (187 ) (53,712 ) Amortization of deferred charge assets 14,359 — — 14,359 Amortization of fair value adjustments 10,114 (2,720 ) (945 ) 6,449 Changes in fair value - fair value option 30,256 — — 30,256 Net incurred losses and LAE $ (190,674 ) $ 69,419 $ 314,806 $ 193,551 Loss Development Information Methodology for Establishing Reserves The liability for losses and LAE includes an amount determined from reported claims and an amount based on historical loss experience and industry statistics for IBNR using a variety of actuarial methods. Our loss reserves cover multiple lines of business, which include workers' compensation, general casualty, asbestos and environmental, marine, aviation and transit, construction defects and other non-life lines of business. Our management, through our loss reserving committees, considers the reasonableness of loss reserves recommended by our actuaries, including actual loss development during the year. Case reserves are recognized for known claims (including the cost of related litigation) when sufficient information has been reported to us to indicate the involvement of a specific insurance policy. We use considerable judgment in estimating losses for reported claims on an individual claim basis based upon our knowledge of the circumstances surrounding the claim, the severity of the injury or damage, the jurisdiction of the occurrence, the potential for ultimate exposure, the type of loss, and our experience with the line of business and policy provisions relating to the particular type of claim. The reserves for unpaid reported losses and LAE are established by management based on reports from brokers, ceding companies and insureds and represent the estimated ultimate cost of events or conditions that have been reported to, or specifically identified, by us. We also consider facts currently known and the current state of the law and coverage litigation. IBNR reserves are established by management based on actuarially determined estimates of ultimate losses and loss expenses. We use generally accepted actuarial methodologies to estimate ultimate losses and LAE and those estimates are reviewed by management. In addition, the routine settlement of claims, at either below or above the carried advised loss reserve, updates historical loss development information to which actuarial methodologies are applied, often resulting in revised estimates of ultimate liabilities. On an annual basis, independent actuarial firms are retained by management to provide their estimates of ultimate losses and to review the estimates developed by our actuaries. Within the annual loss reserve studies produced by either our actuaries or independent actuaries, exposures for each subsidiary are separated into homogeneous reserving categories for the purpose of estimating IBNR. Each reserving category contains either direct insurance or assumed reinsurance reserves and groups relatively similar types of risks and exposures (for example, asbestos, environmental, casualty, property) and lines of business written (for example, marine, aviation, non-marine). Based on the exposure characteristics and the nature of available data for each individual reserving category, a number of methodologies are applied. Recorded reserves for each category are selected from the actuarial indications produced by the various methodologies after consideration of exposure characteristics, data limitations and strengths and weaknesses of each method applied. This approach to estimating IBNR has been consistently adopted in the annual loss reserve studies for each period presented. The estimation of unpaid claim liabilities at any given point in time is subject to a high degree of uncertainty for a number of reasons. A significant amount of time can lapse between the assumption of risk, the occurrence of a loss event, the reporting of the event to an insurance or reinsurance company and the ultimate payment of the claim on the loss event. Our actuarial methodologies include industry benchmarking which, under certain methodologies, compares the trend of our loss development to that of the industry. To the extent that the trend of our loss development compared to the industry changes in any period, it is likely to have an impact on the estimate of ultimate liabilities. Unpaid claim liabilities for property and casualty exposures in general are impacted by changes in the legal environment, jury awards, medical cost trends and general inflation. Certain estimates for unpaid claim liabilities involve considerable uncertainty due to significant coverage litigation, and it can be unclear whether past claim experience will be representative of future claim experience. Ultimate values for such claims cannot be estimated using reserving techniques that extrapolate losses to an ultimate basis using loss development factors, and the uncertainties surrounding the estimation of unpaid claim liabilities are not likely to be resolved in the near future. In addition, reserves are established to cover loss development related to both known and unasserted claims. Consequently, our subsequent estimates of ultimate losses and LAE, and our liability for losses and LAE, may differ materially from the amounts recorded in the consolidated financial statements. These estimates are reviewed regularly and, as experience develops and new information becomes known, the reserves are adjusted as necessary. Such adjustments, if any, will be recorded in earnings in the period in which they become known. Prior period development arises from changes to loss estimates recognized in the current year that relate to loss reserves established in previous calendar years. Asbestos and Environmental In establishing the reserves for losses and LAE related to asbestos and environmental claims, management considers facts currently known and the current state of the law and coverage litigation. Liabilities are recognized for known claims (including the cost of related litigation) when sufficient information has been developed to indicate the involvement of a specific insurance policy, and management can reasonably estimate its liability. In addition, reserves have been established to cover additional exposures on both known and unreported claims. Estimates of the reserves are reviewed and updated continually. Developed case law and claim histories are still evolving for such claims, especially because significant uncertainty exists about the outcome of coverage litigation and whether past claim experience will be representative of future claim experience. In view of the changes in the legal and tort environment that affect the development of such claims, the uncertainties inherent in valuing asbestos and environmental claims are not likely to be resolved in the near future. Ultimate values for such claims cannot be estimated using traditional reserving techniques and there are significant uncertainties in estimating the amount of our potential losses for these claims. There can be no assurance that the reserves established by us will be adequate or will not be adversely affected by the development of other latent exposures. The net liability for unpaid losses and LAE as of December 31, 2019 and 2018 included $2,078.3 million and $1,703.6 million , respectively, which represented an estimate of the net ultimate liability for asbestos and environmental claims. The gross liability for such claims as of December 31, 2019 and 2018 was $2,259.6 million and $1,839.7 million , respectively. For the years ended December 31, 2019 and 2018 , our reserves for asbestos and environmental liabilities increased by $419.9 million and decreased by $152.4 million on a gross basis, respectively, and increased by $374.7 million and decreased by $159.6 million on a net basis, respectively. The increase in 2019 was primarily due to acquisition activity and the decrease in 2018 was primarily due to net paid losses, foreign exchange and net favorable development, partially offset by acquisition activity. Disclosures of Incurred and Paid Loss Development, IBNR, Claims Counts and Payout Percentages The loss development tables disclosed below, sets forth our historic incurred and paid loss development by accident year through December 31, 2019 , net of reinsurance, as well as the cumulative number of reported claims, IBNR balances, and other supplementary information. The loss development tables disclosed below are presented as follows: • Non-Life Run-off - Presented by acquisition year, if significant, and further disaggregated, if significant, by line of business within that acquisition year. The disaggregated lines of business include General Casualty, Workers’ Compensation, Marine, Aviation and Transportation, Professional Indemnity / Directors & Officers and Motor. • Atrium - The loss development disclosures for our Atrium segment have not been disaggregated further by line of business as the segment comprised approximately only 2% of our total consolidated liability for losses and LAE as of December 31, 2019 and was, therefore, not considered material for further disaggregation. • StarStone - All the lines of business related to the StarStone segment have been included within the loss development disclosures below, namely, Casualty, Marine, Property, Aerospace and Workers’ Compensation. Incurred and Paid Loss Development and IBNR Disclosures For each acquisition year and/or line of business for which incurred losses and allocated loss adjustment expenses, net of reinsurance tables have been provided below, the disclosure approach and format adopted reflects the following: • The incurred loss development tables include both reported case reserves and IBNR liabilities, as well as cumulative paid losses; • Both the incurred and cumulative paid loss development tables include allocated LAE (i.e. claims handling costs allocated to specific individual claims) but exclude unallocated LAE (i.e. the costs associated with internal claims staff and third party administrators as well as consultants that cannot be allocated to specific individual claims); • The fair value adjustments related to business acquisitions are excluded from the loss development tables, however the undiscounted incurred losses, cumulative paid losses and allocated LAE related to business acquisitions are included in the loss development tables; • The fair value adjustments related to retroactive reinsurance agreements for which we have elected the fair value option are excluded from the loss development tables, however the undiscounted incurred losses, cumulative paid losses and allocated LAE related to retroactive reinsurance agreements for which we have elected the fair value option are included in the loss development tables; • The amounts relating to the amortization of deferred charge assets are excluded from the loss development tables; • The amounts relating to the increase (reduction) in provisions for unallocated LAE are excluded from the loss development tables; • In the incurred loss development tables, the incurred effect of agreeing a commutation or policy buyback is included in the period in which the commutation or policy buyback is contractually agreed. We reflect the net incurred loss development arising from a commutation or policy buyback in the fiscal year in which a commutation or policy buyback is contractually agreed, and the net incurred loss development is allocated to the appropriate accident year. The claim will generally have been adjusted throughout its lifetime and the amounts recorded in prior years (supplementary information) remain unchanged in our tables, such that the incurred amount that we recognize in the year in which a commutation or policy buyback is contractually agreed represents the effect of the commutation or policy buyback settlement compared to the carried net loss and LAE reserve balance in the prior year. We do not recast prior years to remove commuted or bought back claims, as such practice would eliminate any historical favorable or adverse development we may have experienced on our commuted loss and LAE reserves. Reserves that have been commuted or bought back are not adjusted in future years but the commuted or bought back value remains in our total incurred losses; • In the cumulative paid losses tables, we reflect the amount of the commutation or policy buyback settlements in the year in which they are actually paid or received, and the net payment is allocated to the appropriate accident year. The claim or recoverable may have recorded payments or receipts throughout its lifetime and amounts recorded in prior years (supplementary information) remain unchanged in our tables, such that the amounts paid or received that we recognize in the year in which a commutation or policy buyback is paid or received represents the amount actually paid or received. We do not recast prior years to remove payments or receipts related to commutations or policy buybacks, as we consider commutations and policy buybacks a key component of our business and reflective of our ability to effectively manage acquired losses and LAE liabilities. Payments relating to commutations and policy buybacks are not adjusted in future years but the payments remain in our total cumulative paid losses; • The amounts included within the loss development tables for the years ended December 31, 2010 through to December 31, 2018 (April 1, 2014 through to December 31, 2018 in the case of StarStone since its date of acquisition), as well as the historical average annual percentage payout ratios as of December 31, 2019 , are presented as supplementary information and are therefore unaudited; • All data presented within the loss development tables is net of reinsurance recoveries, excluding provisions for uncollectible reinsurance recoverables; • All data presented within the loss development tables is net of intercompany activity, including the Intra-Group Cessions within the StarStone segment. On May 14, 2018, we completed the acquisition of KaylaRe and subsequently eliminated all the related intercompany balances. In the loss development disclosures provided in our Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2017, the StarStone loss triangles were presented net of the external reinsurance provided by KaylaRe since it was not a consolidated subsidiary at that time. However, after the acquisition of KaylaRe in May 2018, the reinsurance arrangement with StarStone became an intercompany transaction and was eliminated on consolidation. In addition, the StarStone loss development disclosures relating to the prior years (supplementary information) were retrospectively recast as if KaylaRe had always been a consolidated subsidiary, to allow for comparability between fiscal years; • The IBNR reserves included within each incurred loss development table by accident year, reflect the net IBNR recorded as of December 31, 2019 , including expected development on reported losses; • For the Non-life Run-off segment loss development tables, all information for both acquisitions and retroactive reinsurance agreements is presented prospectively. As the reserves are effectively re-underwritten at the date the reserves are acquired or assumed, we believe that the historical loss development prior to being acquired is not relevant to our own experience managing these reserves. In addition, the information required to prepare the loss development disclosures on a retrospective basis is not always available to us and a mixed approach would result in loss development tables that are not entirely reflective of the actual loss development; • For the Non-life Run-off segment we have also presented the net incurred and paid losses and ALAE information by calendar year as well as IBNR and claim counts for accident years older than 10 years on a single row within the loss development tables. This presentation differs from the typical approach where only the net outstanding losses and LAE reserves are presented as a reconciling item at the bottom of the loss development tables. The additional detailed disclosures are provided on a voluntary basis and the inclusion of the disclosures is to provide additional information to the users of our financial statements and to also enable the reconciliation of our total loss reserves by acquisition year and by significant line of business. • For the StarStone segment loss development tables, all information has been presented on a prospective basis from the date of our acquisition of StarStone, which was effective on April 1, 2014. Providing pre-acquisition incurred and paid losses by accident year for years prior to 2014 was determined to be impracticable due to significant data limitations; and • For the Atrium segment loss development tables, all information has been presented on a retrospective basis. The historical amounts disclosed within the loss development tables for all lines of business presented below are on a constant-currency basis, which is achieved by using constant foreign exchange rates between periods in the loss development tables , and translating prior period amounts denominated in currencies other than the U.S. dollar, which is our reporting currency, using the closing exchange rates as of December 31, 2019 . The impact of this exchange rate conversion is to show the change between periods exclusive of the effect of exchange rate fluctuations, which would otherwise distort the change in incurred losses and the cash flow patterns associated with those incurred losses shown within the loss development tables. The change in net incurred losses shown within the loss development tables will, however, differ from other U.S. GAAP disclosures of incurred current and prior period reserve development amounts, which include the effect of exchange rate fluctuations. Establishing an estimate for loss reserves involves various assumptions and judgments, therefore, the information contained within the loss development disclosures only allows readers or users of our consolidated financial statements to understand, at the summary level presented in the development tables, the change over time in our reported incurred loss estimates as well as the nature and patterns of the cash flows associated with those estimates. We, therefore, believe that the information provided within the loss development tables disclosed below is of limited use for independent analysis or application of standard actuarial estimations, and any results obtained from doing so should be interpreted with caution. Cumulative Number of Reported Claims Reported claim counts, on a cumulative basis, are provided as supplemental information to each incurred loss development table by accident year. We measure claim frequency information on an individual claim count basis within each of our segments as follows: • Non-Life Run-off - The claim frequency information for the exposures included within our Non-life Run-off lines of business includes direct and assumed open and closed claims by accident year at the claimant level. Reported claims that are closed without a payment are included within our cumulative number of reported claims because we typically incur claim adjustment expenses on them prior to their closure. The claim count numbers exclude counts related to claims within policy deductibles where the insured is responsible for the payment of losses within the deductible layer. Individual claim counts related to certain assumed reinsurance contracts such as excess-of-loss and quota share treaties are not available to us, and the losses arising from these treaties have been treated as single claims for the purposes of determining claim counts. Therefore, each treaty year within the reinsurance contract is deemed a single claim because the detailed underlying individual claim information is generally not reported to us by our cedents; and • StarStone and Atrium - The claim frequency information is determined at the claimant level for the exposures within the lines of business related to these segments. Our claims system assigns a unique claim identifier to each reported claim we receive. Each unique claim identifier is deemed to be a single claim, irrespective of whether the claim remains open or has been closed with or without payment. For certain insurance facilities and business produced or managed by managing general agents, coverholders and third party administrators where the underlying claims data is reported to us in an aggregated format, the information necessary to provide cumulative claims frequency is not available. In such cases, we typically record a “block” claim in our system. This also applies to a small amount of assumed reinsurance business that we write where, similarly, the underlying claims data is reported to us in an aggregated format. In such instances, each assumed reinsurance contract is deemed a single claim. The cumulative number of reported claims for our Atrium segment includes all claim counts for Syndicate 609. Our Atrium segment represents our 25% share of Syndicate 609's underwriting capacity and capital, however, the claims count is the same whether viewed at the 100% Syndicate level or for our 25% share. Our reported claim frequency information is subject to the following inherent limitations when analyzing our loss experience and severity: • Claim counts are presented only on a reported and not on an ultimate basis. Therefore, reported claim counts include open claims which have outstanding reserves but exclude IBNR claims. As such the reported claims are consistent with reported losses, which can be calculated by subtracting IBNR losses from incurred losses. However, the reported claim counts are inconsistent with the losses in the incurred loss development tables, which include IBNR losses, and to losses in the paid loss development tables, which exclude outstanding reserves; • Reported claim counts have not been adjusted for ceded reinsurance, which may distort any measures of frequency or severity; • For lines of business that have a mix of primary and excess layer exposures, such as our general casualty and workers’ compensation lines of business, the reported claim counts may fluctuate from period to period between exposure layers, thereby distorting any measure of frequency and severity; and • The use of our reported claim frequency information to project ultimate loss payouts by disaggregated disclosure category or line of business may not be as meaningful as claim count information related to individual contracts at a more granular level. Payout Percentages • Non-life Run-off - The annual percentage payout disclosures for our Non-life Run-off segment are based on the payout of incurred claims by age, net of reinsurance. For our Non-life Run-off segment, claims aging reflects the number of years that have lapsed since the original acquisition of the related net liability for losses and LAE reserves to the date the claim is paid. There may be occasions where, due to our claims management strategies (including commutations and policy buy-backs) or due to the timing of claims payments relative to the associated recovery, the cash received from reinsurance recoveries is greater than the cash paid out to our claimants, (i.e. a net recovery rather than a net payout for a particular calendar year), thereby resulting in a negative annual percentage payout for that calendar year. • Atrium and StarStone - The average annual percentage payout disclosures for our Atrium and StarStone segments are based on the payout of incurred claims by age, net of reinsurance. Non-Life Run-off Segment The table below provides a reconciliation of the beginning and ending reserves for losses and LAE for the years ended December 31, 2019 , 2018 and 2017 for the Non-life Run-off segment: 2019 2018 2017 Balance as at January 1 $ 7,540,662 $ 5,949,472 $ 4,716,363 Less: reinsurance reserves recoverable 1,366,123 1,377,485 1,000,953 Less: deferred charge assets on retroactive reinsurance 86,585 80,192 94,551 Net balance as at January 1 6,087,954 4,491,795 3,620,859 Net incurred losses and LAE: Current period 123,559 12,451 5,866 Prior periods (71,934 ) (318,518 ) (196,540 ) Total net incurred losses and LAE 51,625 (306,067 ) (190,674 ) Net paid losses: Current period (64,820 ) (5 ) (2,835 ) Prior periods (1,182,804 ) (838,812 ) (578,888 ) Total net paid losses (1,247,624 ) (838,817 ) (581,723 ) Effect of exchange rate movement 47,355 (132,632 ) 138,772 Acquired on purchase of subsidiaries 686 1,111,839 10,251 Assumed business 1,586,307 1,761,836 1,494,310 Ceded business (47,018 ) — — Net balance as at December 31 6,479,285 6,087,954 4,491,795 Plus: reinsurance reserves recoverable 1,543,614 1,366,123 1,377,485 Plus: deferred charge assets on retroactive reinsurance 272,462 86,585 80,192 Balance as at December 31 $ 8,295,361 $ 7,540,662 $ 5,949,472 Net incurred losses and LAE in the Non-life Run-off segment for the years ended December 31, 2019 , 2018 and 2017 were as follows: 2019 2018 2017 Prior Period Current Period Total Prior Period Current Period Total Prior Period Current Period Total Net losses paid $ 1,182,804 $ 64,820 $ 1,247,624 $ 838,812 $ 5 $ 838,817 $ 578,888 $ 2,835 $ 581,723 Net change in case and LAE reserves (553,996 ) 23,105 (530,891 ) (552,124 ) 4,704 (547,420 ) (381,450 ) 397 (381,053 ) Net change in IBNR reserves (848,776 ) 35,194 (813,582 ) (573,127 ) 7,742 (565,385 ) (393,100 ) 2,373 (390,727 ) Increase (reduction) in estimates of net ultimate losses (219,968 ) 123,119 (96,849 ) (286,439 ) 12,451 (273,988 ) (195,662 ) 5,605 (190,057 ) Reduction in provisions for bad debt — — — — — — (1,536 ) — (1,536 ) Increase (reduction) in provisions for unallocated LAE (57,844 ) 440 (57,404 ) (65,401 ) — (65,401 ) (54,071 ) 261 (53,810 ) Amortization of deferred charge assets 38,627 — 38,627 13,781 — 13,781 14,359 — 14,359 Amortization of fair value adjustments 50,070 — 50,070 12,877 — 12,877 10,114 — 10,114 Changes in fair value - fair value option 117,181 — 117,181 6,664 — 6,664 30,256 — 30,256 Net incurred losses and LAE $ (71,934 ) $ 123,559 $ 51,625 $ (318,518 ) $ 12,451 $ (306,067 ) $ (196,540 ) $ 5,866 $ (190,674 ) Net change in case and LAE reserves comprises the movement during the year in specific case reserve liabilities as a result of claims settlements or changes advised to us by our policyholders and attorneys, less changes in case reserves recoverable advised by us to our reinsurers as a result of the settlement or movement of assumed claims. Net change in IBNR represents the gross change in our actuarial estimates of IBNR, less amounts recoverable. Year Ended December 31, 2019 The increase in net incurred losses and LAE

Defendant Asbestos and Environm

Defendant Asbestos and Environmental Liabilities	12 Months Ended
	Dec. 31, 2019
Liability for Asbestos and Environmental Claims [Abstract]
DEFENDANT ASBESTOS AND ENVIRONMENTAL LIABILITIES	11. DEFENDANT ASBESTOS AND ENVIRONMENTAL LIABILITIES We acquired DCo on December 30, 2016, and Morse TEC on October 30, 2019, as described in Note 3 - "Acquisitions" . DCo and Morse TEC hold liabilities associated with personal injury asbestos claims and environmental claims arising from their legacy manufacturing operations . These companies continue to process asbestos personal injury claims in the normal course of business. Defendant asbestos liabilities on our consolidated balance sheets include amounts for loss payments and defense costs for pending and future asbestos-related claims, determined using standard actuarial techniques for asbestos exposures. Defendant environmental liabilities include estimated clean-up costs associated with the acquired companies' former operations based on engineering reports. Included within insurance balances recoverable and defendant asbestos and environmental liabilities are the fair value adjustments that were initially recognized upon acquisition. These fair value adjustments are amortized in proportion to the actual payout of claims and recoveries. The carrying value of the asbestos and environmental liabilities, insurance recoveries, future estimated expenses and the fair value adjustments related to DCo and Morse TEC as of December 31, 2019 and 2018 was as follows: 2019 2018 Defendant asbestos and environmental liabilities: Defendant asbestos liabilities $ 1,100,593 $ 265,975 Defendant environmental liabilities 10,279 2,152 Estimated future expenses 51,637 19,843 Fair value adjustments (314,824 ) (84,650 ) Defendant asbestos and environmental liabilities 847,685 203,320 Insurance balances recoverable: Insurance recoveries related to defendant asbestos and environmental liabilities 549,593 183,676 Fair value adjustments (100,738 ) (47,868 ) Insurance balances recoverable 448,855 135,808 Net liabilities relating to defendant asbestos and environmental exposures $ 398,830 $ 67,512 The table below provides a consolidated reconciliation of the beginning and ending liability for defendant asbestos and environmental exposures for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Balance as at January 1 203,320 219,164 234,020 Less: Insurance balances recoverable 135,808 122,326 133,032 Net balance as at January 1 67,512 96,838 100,988 Total net paid claims (13,708 ) (6,351 ) (6,927 ) Amounts recorded in other income (expense): Net change in actuarial estimates (4,263 ) (23,221 ) 2,800 Amortization of fair value adjustments 13,500 246 (23 ) Total other expense (income) 9,237 (22,975 ) 2,777 Acquired on purchase of subsidiaries 335,789 — — Net balance as at December 31 398,830 67,512 96,838 Plus: Insurance balances recoverable 448,855 135,808 122,326 Balance as at December 31 847,685 203,320 219,164 Methodologies for determining liabilities Defendant Asbestos Liabilities DCo and Morse TEC review, on an ongoing basis, their own experience in handling asbestos-related claims and trends affecting asbestos-related claims in the U.S. tort system generally, for the purposes of assessing the value of pending asbestos-related claims and the number and value of those that may be asserted in the future, as well as potential recoveries from DCo and Morse TEC’s insurance carriers with respect to such claims and defense costs. The actuarial analysis for these asbestos-related exposures utilizes data resulting from the claim review process, including input from national coordinating counsel and local counsel, and includes the development of an estimate of the potential value of asbestos-related claims asserted but not yet resolved as well as the number and potential value of asbestos-related claims not yet asserted. In developing the estimate of liability for potential future claims, the actuarial analysis projects the potential number of future claims based on DCo and Morse TEC’s historical claim filings and epidemiological studies. The actuarial analysis also utilizes assumptions based on the DCo and Morse TEC’s historical proportion of claims resolved without payment, historical claim resolution costs for those claims that result in a payment, and historical defense costs. The liabilities are then estimated by multiplying the pending and projected future claim filings by projected payments rates and average claim resolution amounts and then adding an estimate for defense costs. DCo and Morse TEC determine, based on the factors described above, including the actuarial analysis, that their best estimate of the aggregate liability both for asbestos-related claims asserted but not yet resolved and potential asbestos-related claims not yet asserted, including estimated defense costs, was $1,100.6 million and $266.0 million as of December 31, 2019 and 2018 , respectively. This liability reflects the actuarial central estimate, which is intended to represent an expected value of the most probable outcome. Defendant Environmental Liabilities As a result of our acquisition of DCo and Morse TEC, we have been identified by the United States Environmental Protection Agency and certain U.S. state environmental agencies and private parties as potentially responsible parties ("PRP") at various hazardous waste disposal sites under the Comprehensive Environmental Response, Compensation and Liability Act ("Superfund") and equivalent U.S. state laws. The PRPs may currently be liable for the cost of clean-up and other remedial activities at 22 such sites. Responsibility for clean-up and other remedial activities at a Superfund site is typically shared among PRPs based on an allocation formula. We have a liability for defendant environmental liabilities of $10.3 million and $2.2 million as o f December 31, 2019 and 2018

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	12. FAIR VALUE MEASUREMENTS Fair Value Hierarchy Fair value is defined as the price at which to sell an asset or transfer a liability (i.e. the "exit price") in an orderly transaction between market participants. We use a fair value hierarchy that gives the highest priority to quoted prices in active markets and the lowest priority to unobservable data. The hierarchy is broken down into three levels as follows: • Level 1 - Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access. Valuation adjustments and block discounts are not applied to Level 1 instruments. • Level 2 - Valuations based on quoted prices in active markets for similar assets or liabilities, quoted prices for identical assets or liabilities in inactive markets, or for which significant inputs are observable (e.g. interest rates, yield curves, prepayment speeds, default rates, loss severities, etc.) or can be corroborated by observable market data. • Level 3 - Valuations based on unobservable inputs where there is little or no market activity. Unadjusted third party pricin g sources or management's assumptions and internal valuation models may be used to determine the fair values. In addition, certain of our other investments are measured at fair value using net asset value ("NAV") per share (or its equivalent) as a practical expedient and have not been classified within the fair value hierarchy above. We have categorized our assets and liabilities that are recorded at fair value on a recurring basis among levels based on the observability of inputs, or at fair value using NAV per share (or its equivalent) as follows: December 31, 2019 Quoted Prices in Significant Significant Fair Value Based on NAV as Practical Expedient Total Fair Investments: Fixed maturity investments: U.S. government and agency $ — $ 736,043 $ — $ — $ 736,043 U.K. government — 161,772 — — 161,772 Other government — 702,857 — — 702,857 Corporate — 5,697,067 — — 5,697,067 Municipal — 167,882 — — 167,882 Residential mortgage-backed — 471,836 — — 471,836 Commercial mortgage-backed — 900,029 — — 900,029 Asset-backed — 775,402 — — 775,402 $ — $ 9,612,888 $ — $ — $ 9,612,888 Other assets included within funds held - directly managed — 14,207 — — 14,207 Equities: Publicly traded equity investments $ 297,310 $ 30,565 $ — $ — $ 327,875 Exchange-traded funds 133,047 — — — 133,047 Privately held equity investments — — 268,799 — 268,799 $ 430,357 $ 30,565 $ 268,799 $ — $ 729,721 Other investments: Hedge funds $ — $ — $ — $ 1,121,904 $ 1,121,904 Fixed income funds — 398,143 — 82,896 481,039 Equity funds — 111,040 — 299,109 410,149 Private equity funds — — — 329,885 329,885 CLO equities — — 87,555 — 87,555 CLO equity funds — — — 87,509 87,509 Other — 34 314 6,031 6,379 $ — $ 509,217 $ 87,869 $ 1,927,334 $ 2,524,420 Total Investments $ 430,357 $ 10,166,877 $ 356,668 $ 1,927,334 $ 12,881,236 Cash and cash equivalents $ 173,892 $ 222,191 $ — $ — $ 396,083 Reinsurance balances recoverable on paid and unpaid losses: $ — $ — $ 695,518 $ — $ 695,518 Other Assets: Derivatives qualifying as hedging $ — $ 642 $ — $ — $ 642 Derivatives not qualifying as hedges $ — $ 1,369 $ — $ — $ 1,369 Derivative instruments $ — $ 2,011 $ — $ — $ 2,011 Losses and LAE: $ — $ — $ 2,621,122 $ — $ 2,621,122 Other Liabilities: Derivatives qualifying as hedging $ — $ 11,452 $ — $ — $ 11,452 Derivatives not qualifying as hedges $ — $ 4,106 $ — $ — $ 4,106 Derivative instruments $ — $ 15,558 $ — $ — $ 15,558 December 31, 2018 Quoted Prices in Significant Significant Fair Value Based on NAV as Practical Expedient Total Fair Investments: Fixed maturity investments: U.S. government and agency $ — $ 510,245 $ — $ — $ 510,245 U.K government — 300,631 — — 300,631 Other government — 793,810 — — 793,810 Corporate — 4,802,454 37,386 — 4,839,840 Municipal — 130,265 — — 130,265 Residential mortgage-backed — 773,557 — — 773,557 Commercial mortgage-backed — 705,674 7,389 — 713,063 Asset-backed — 627,360 9,121 — 636,481 $ — $ 8,643,996 $ 53,896 $ — $ 8,697,892 Other assets included within funds held - directly managed $ — $ 14,780 $ — $ — $ 14,780 Equities: Publicly traded equity investments $ 102,102 $ 36,313 $ — $ — $ 138,415 Privately held equity investments — — 228,710 — 228,710 $ 102,102 $ 36,313 $ 228,710 $ — $ 367,125 Other investments: Hedge funds $ — $ — $ — $ 852,584 $ 852,584 Fixed income funds — 290,864 — 112,994 403,858 Equity funds — 100,440 — 233,241 333,681 Private equity funds — — — 248,628 248,628 CLO equities — — 39,052 — 39,052 CLO equity funds — — — 37,260 37,260 Private credit funds — — — 33,381 33,381 Other — 578 315 8,420 9,313 $ — $ 391,882 $ 39,367 $ 1,526,508 $ 1,957,757 Total Investments $ 102,102 $ 9,086,971 $ 321,973 $ 1,526,508 $ 11,037,554 Cash and cash equivalents $ 243,839 $ 21,146 $ — $ — $ 264,985 Reinsurance recoverable: $ — $ — $ 739,591 $ — $ 739,591 Other Assets: Derivatives qualifying as hedging $ — $ 1,615 $ — $ — $ 1,615 Derivatives not qualifying as hedges — 5,086 — — 5,086 Derivative instruments $ — $ 6,701 $ — $ — $ 6,701 Losses and LAE: $ — $ — $ 2,874,055 $ — $ 2,874,055 Other Liabilities: Derivatives qualifying as hedging $ — $ 300 $ — $ — $ 300 Derivatives not qualifying as hedges — 683 — — 683 Derivative instruments $ — $ 983 $ — $ — $ 983 Valuation Methodologies of Financial Instruments Measured at Fair Value Fixed Maturity Investments The fair values for all securities in the fixed maturity investments and funds held - directly managed portfolios are independently provided by the investment accounting service providers, investment managers and investment custodians, each of which utilize internationally recognized independent pricing services. We record the unadjusted price provided by the investment accounting service providers, investment managers or investment custodians and validate this price through a process that includes, but is not limited to: (i) comparison of prices against alternative pricing sources; (ii) quantitative analysis (e.g. comparing the quarterly return for each managed portfolio to its target benchmark); (iii) evaluation of methodologies used by external parties to estimate fair value, including a review of the inputs used for pricing; and (iv) comparing the price to our knowledge of the current investment market. Our internal price validation procedures and review of fair value methodology documentation provided by independent pricing services have not historically resulted in adjustment in the prices obtained from the pricing service. The independent pricing services used by the investment accounting service providers, investment managers and investment custodians obtain actual transaction prices for securities that have quoted prices in active markets. Where we utilize single unadjusted broker-dealer quotes, they are generally provided by market makers or broker-dealers who are recognized as market participants in the markets for which they are providing the quotes. For determining the fair value of securities that are not actively traded, in general, pricing services use "matrix pricing" in which the independent pricing service uses observable market inputs including, but not limited to, reported trades, benchmark yields, broker-dealer quotes, interest rates, prepayment speeds, default rates and other such inputs as are available from market sources to determine a reasonable fair value. In addition, pricing services use valuation models, using observable data, such as an Option Adjusted Spread model, to develop prepayment and interest rate scenarios. The Option Adjusted Spread model is commonly used to estimate fair value for securities such as mortgage-backed and asset-backed securities. The following describes the techniques generally used to determine the fair value of our fixed maturity investments by asset class, including the investments underlying the funds held - directly managed. • U.S. government and agency securities consist of securities issued by the U.S. Treasury and mortgage pass-through agencies such as the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation and other agencies. Non-U.S. government securities consist of bonds issued by non-U.S. governments and agencies along with supranational organizations. The significant inputs used to determine the fair value of these securities include the spread above the risk-free yield curve, reported trades and broker-dealer quotes. These are considered to be observable market inputs and, therefore, the fair values of these securities are classified as Level 2. • Corporate securities consist primarily of investment-grade debt of a wide variety of corporate issuers and industries. The fair values of these securities are determined using the spread above the risk-free yield curve, reported trades, broker-dealer quotes, benchmark yields, and industry and market indicators. These are considered observable market inputs and, therefore, the fair values of these securities are classified as Level 2. Where pricing is unavailable from pricing services, such as in periods of low trading activity or when transactions are not orderly, we obtain non-binding quotes from broker-dealers. Where significant inputs are unable to be corroborated with market observable information, we classify the securities as Level 3. • Municipal securities consist primarily of bonds issued by U.S.-domiciled state and municipal entities. The fair values of these securities are determined using the spread above the risk-free yield curve, reported trades, broker-dealer quotes and benchmark yields. These are considered observable market inputs and, therefore, the fair values of these securities are classified as Level 2. • Asset-backed securities consist primarily of investment-grade bonds backed by pools of loans with a variety of underlying collateral. Residential and commercial mortgage-backed securities include both agency and non-agency originated securities. Where pricing is unavailable from pricing services, we obtain non-binding quotes from broker-dealers. This is generally the case when there is a low volume of trading activity and current transactions are not orderly. The significant inputs used to determine the fair value of these securities include the spread above the risk-free yield curve, reported trades, benchmark yields, prepayment speeds and default rates. The fair values of these securities are classified as Level 2 if the significant inputs are market observable. Where significant inputs are unable to be corroborated with market observable information, we classify the securities as Level 3. Equities Our investments in equities consist of a combination of publicly and privately traded investments. Our publicly traded equity investments in common and preferred stocks predominantly trade on major exchanges and are managed by our external advisors. Our publicly traded equities are widely diversified and there is no significant concentration in any specific industry. Our exchange-traded funds trade on major exchanges. We use an internationally recognized pricing service to estimate the fair value of our publicly traded equities and exchange-traded funds. We have categorized the majority of our publicly traded equity investments, other than preferred stock, and our exchange-traded funds as Level 1 investments because the fair values of these investments are based on unadjusted quoted prices in active markets for identical assets. One equity security is trading in an inactive market and, as a result has been classified as Level 2. The fair value estimates of our investments in publicly traded preferred stock are based on observable market data and, as a result, have been categorized as Level 2. Our privately held equity investments in common and preferred stocks are direct investments in companies that we believe offer attractive risk adjusted returns and/or offer other strategic advantages. Each investment may have its own unique terms and conditions and there may be restrictions on disposals. The market for these investments is illiquid and there is no active market. We use a combination of cost, internal models, reported values from co-investors/managers and observable inputs, such as capital raises and capital transactions between new and existing shareholders to calculate the fair value of the privately held equity investments. Other investments, at fair value We have ongoing due diligence processes with respect to the other investments carried at fair value in which we invest and their managers. These processes are designed to assist us in assessing the quality of information provided by, or on behalf of, each fund and in determining whether such information continues to be reliable or whether further review is warranted. Certain funds do not provide full transparency of their underlying holdings; however, we obtain the audited financial statements for funds annually, and regularly review and discuss the fund performance with the fund managers to corroborate the reasonableness of the reported net asset values ("NAV"). The use of NAV as an estimate of the fair value for investments in certain entities that calculate NAV is a permitted practical expedient. Due to the time lag in the NAV reported by certain fund managers we adjust the valuation for capital calls and distributions. Other investments measured at fair value using NAV as a practical expedient have not been classified in the fair value hierarchy. Other investments for which we do not use NAV as a practical expedient have been valued using prices from independent pricing services, investment managers and broker-dealers. The following describes the techniques generally used to determine the fair value of our other investments. • For our investments in hedge funds, we measure fair value by obtaining the most recently available NAV as advised by the external fund manager or third-party administrator. The fair values of these investments are measured using the NAV as a practical expedient and therefore have not been categorized within the fair value hierarchy. • Our investments in fixed income funds and equity funds are valued based on a combination of prices from independent pricing services, external fund managers or third-party administrators. For the publicly available prices we have classified the investments as Level 2. For the non-publicly available prices we are using NAV as a practical expedient and therefore these have not been categorized within the fair value hierarchy. • For our investments in private equity funds, we measure fair value by obtaining the most recently available NAV from the external fund manager or third-party administrator. The fair values of these investments are measured using the NAV as a practical expedient and therefore have not been categorized within the fair value hierarchy. • We measure the fair value of our direct investment in CLO equities based on valuations provided by independent pricing services, our external CLO equity manager, and valuations provided by the broker or lead underwriter of the investment (the "broker"). Our CLO equity investments have been classified as Level 3 due to the use of unobservable inputs in the valuation and the limited number of relevant trades in secondary markets. In providing valuations, the independent pricing service providers, CLO equity manager and brokers use observable and unobservable inputs. Of the significant unobservable market inputs used, the default and loss severity rates involve the most judgment and create the most sensitivity. A significant increase or decrease in either of these significant inputs in isolation would result in lower or higher fair value estimates for direct investments in CLO equities and, in general, a change in default rate assumptions will be accompanied by a directionally similar change in loss severity rate assumptions. Collateral spreads and estimated maturity dates are less subjective inputs because they are based on the historical average of actual spreads and the weighted average life of the current underlying portfolios, respectively. A significant increase or decrease in either of these significant inputs in isolation would result in higher or lower fair value estimates for direct investments in CLO equities. In general, these inputs have no significant interrelationship with each other or with default and loss severity rates. On a quarterly basis, we receive the valuation from the independent pricing providers, external CLO manager and brokers and then review the underlying cash flows and key assumptions used by them. We review and update the significant unobservable inputs based on information obtained from secondary markets. These inputs are our responsibility and we assess the reasonableness of the inputs (and if necessary, update the inputs) through communicating with industry participants, monitoring of the transactions in which we participate (for example, to evaluate default and loss severity rate trends), and reviewing market conditions, historical results, and emerging trends that may impact future cash flows. If valuations from the independent pricing service providers, external CLO equity manager or brokers are not available, we use an income approach based on certain observable and unobservable inputs to value these investments. An income approach is also used to corroborate the reasonableness of the valuations provided by the pricing providers, external manager and brokers. Where an income approach is followed, the valuation is based on available trade information, such as expected cash flows and market assumptions on default and loss severity rates. Other inputs used in the valuation process include asset spreads, loan prepayment speeds, collateral spreads and estimated maturity dates. • For our investments in the CLO equity funds, we measure fair value by obtaining the most recently available NAV as advised by the external fund manager or third party administrator. The fair value of these investments is measured using the NAV as a practical expedient and therefore have not been categorized within the fair value hierarchy. • For our investments in private credit funds, we measure fair value by obtaining the most recently available NAV from the external fund manager or third-party administrator. The fair values of these investments are measured using the NAV as a practical expedient and therefore have not been categorized within the fair value hierarchy. • Included within other is an investment in a real estate debt fund, for which we measure fair value by obtaining the most recently available NAV from the external fund manager or third-party administrator. The fair value of this investment is measured using the NAV as a practical expedient and therefore has not been categorized within the fair value hierarchy. Insurance Contracts - Fair Value Option The Company uses an internal model to calculate the fair value of the liability for losses and loss adjustment expenses and reinsurance balances recoverable on paid and unpaid losses for certain retroactive reinsurance contracts where we have elected the fair value option in our Non-life Run-off segment. The fair value was calculated as the aggregate of discounted cash flows plus a risk margin. The discounted cash flow approach uses (i) estimated nominal cash flows based upon an appropriate payment pattern developed in accordance with standard actuarial techniques and (ii) a discount rate based upon a high quality rated corporate bond plus a credit spread for non-performance risk. The model uses corporate bond rates across the yield curve depending on the estimated timing of the future cash flows and specific to the currency of the risk. The risk margin was calculated using the present value of the cost of capital. The cost of capital approach uses (i) projected capital requirements, (ii) multiplied by the risk cost of capital representing the return required for non-hedgeable risk based upon the weighted average cost of capital less investment income and (iii) discounted using the weighted average cost of capital. Derivative Instruments The fair values of our foreign currency exchange contracts, as described in Note 7 - "Derivatives and Hedging Instruments" are classified as Level 2. The fair values are based upon prices in active markets for identical contracts. Level 3 Measurements and Changes in Leveling Transfers into or out of levels are recorded at their fair values as of the end of the reporting period, consistent with the date of determination of fair value. Investments The following table presents a reconciliation of the beginning and ending balances for all investments measured at fair value on a recurring basis using Level 3 inputs during the years ended December 31, 2019 and 2018 : 2019 Fixed maturity investments Privately-held Equities Other Investments Total Corporate Residential mortgage-backed Commercial mortgage-backed Asset-backed Beginning fair value $ 37,386 $ — $ 7,389 $ 9,121 $ 228,710 $ 39,367 $ 321,973 Purchases 184 — — — 33,713 56,908 90,805 Sales (3,520 ) — (784 ) (5,088 ) (2,016 ) (590 ) (11,998 ) Total realized and unrealized gains (losses) 90 (1 ) 64 241 8,392 (7,816 ) 970 Transfer into Level 3 from Level 2 3,535 102 1,515 22,771 — — 27,923 Transfer out of Level 3 into Level 2 (37,675 ) (101 ) (8,184 ) (27,045 ) — — (73,005 ) Ending fair value $ — $ — $ — $ — $ 268,799 $ 87,869 $ 356,668 2018 Fixed maturity investments Privately-held Equities Other Investments Total Corporate Residential mortgage-backed Commercial mortgage-backed Asset-backed Beginning fair value $ 67,178 $ 3,080 $ 21,494 $ 27,892 $ — $ 57,079 $ 176,723 Purchases 14,391 — 3,749 46,074 227,000 13,173 304,387 Sales (65,700 ) (1,184 ) (5,781 ) (49,020 ) — (12,091 ) (133,776 ) Total realized and unrealized losses (57 ) (28 ) (645 ) (1,843 ) (2 ) (18,794 ) (21,369 ) Transfer into Level 3 from Level 2 28,339 1,795 4,897 9,890 1,712 — 46,633 Transfer out of Level 3 into Level 2 (6,765 ) (3,663 ) (16,325 ) (23,872 ) — — (50,625 ) Ending fair value $ 37,386 $ — $ 7,389 $ 9,121 $ 228,710 $ 39,367 $ 321,973 Net realized and unrealized gains related to Level 3 assets in the table above are included in net realized and unrealized (losses) gains in our consolidated statements of earnings. The securities transferred from Level 2 to Level 3 were transferred due to insufficient market observable inputs for the valuation of the specific assets. The transfers from Level 3 to Level 2 were based upon obtaining market observable information regarding the valuations of the specific assets. Valuations Techniques and Inputs The table below presents the quantitative information related to the fair value measurements for investments measured at fair value on a recurring basis using Level 3 inputs for the year ended December 31, 2019: Qualitative Information about Level 3 Fair Value Measurements Fair Value at December 31, 2019 Valuation Techniques Unobservable Input Range (Average) (1) (in millions of U.S. dollars) CLO equities $87.6 Consensus pricing Offered quotes 14-87 (48) Discounted Cash Flow method Discount rate (%) (2) Recovery rate (3) Prepayment rate (4) Collateral reinvestment coupon floor (5) 10%-30% (19.5%) Privately held equity investments 268.8 Transactional value Implied price at recent purchase transaction 13.50 - 13.85 Cost as approximation of fair value Cost as approximation of fair value (1) The average represents the arithmetic average of the inputs and is not weighted by the relative fair value. (2) Implied yields were determined from recent market color of comparable subordinated notes, as well as unique characteristics for each investment. (3) For collateral which has already defaulted, a recovery rate equal to the current market value of the collateral was assumed. (4) An assumed constant prepayment rate (CPR) was applied to the CLOs. CPRs are the annualized percentage of loans in the collateral pool that prepay. (5) It was assumed that the collateral manager would reinvest into collateral with a similar weighted-average spread and a similar ratings composition to the current collateral pool. Insurance Contracts - Fair Value Option The following table presents a reconciliation of the beginning and ending balances for all insurance contracts measured at fair value on a recurring basis using Level 3 inputs during the years ended December 31, 2019 and 2018 : 2019 2018 Liability for losses and LAE Reinsurance balances recoverable on paid and unpaid losses Net Liability for losses and LAE Reinsurance balances recoverable on paid and unpaid losses Net Beginning fair value $ 2,874,055 $ 739,591 $ 2,134,464 $ 1,794,669 $ 542,224 $ 1,252,445 Assumed business 9,218 — 9,218 1,890,061 372,780 1,517,281 Incurred losses and LAE: Reduction in estimates of ultimate losses (32,690 ) (2,958 ) (29,732 ) (108,429 ) (30,041 ) (78,388 ) Reduction in unallocated LAE (19,915 ) — (19,915 ) (20,656 ) — (20,656 ) Change in fair value 160,630 43,449 117,181 27,845 21,181 6,664 Total incurred losses and LAE 108,025 40,491 67,534 (101,240 ) (8,860 ) (92,380 ) Paid losses (416,770 ) (92,145 ) (324,625 ) (576,949 ) (148,175 ) (428,774 ) Effect of exchange rate movements 46,594 7,581 39,013 (132,486 ) (18,378 ) (114,108 ) Ending fair value $ 2,621,122 $ 695,518 $ 1,925,604 $ 2,874,055 $ 739,591 $ 2,134,464 Changes in fair value in the table above are included in net incurred losses and LAE in our consolidated statements of earnings. The following table presents the components of the net change in fair value for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Changes in fair value due to changes in: Duration $ 22,719 $ 74,011 $ 41,332 Corporate bond yield 94,462 (71,031 ) (11,076 ) Risk cost of capital — 3,684 — Change in fair value $ 117,181 $ 6,664 $ 30,256 Below is a summary of the quantitative information regarding the significant observable and unobservable inputs used in the internal model to determine fair value on a recurring basis as of December 31, 2019 and 2018 : 2019 2018 Valuation Technique Unobservable (U) and Observable (O) Inputs Weighted Average Weighted Average Internal model Corporate bond yield (O) A rated A rated Internal model Credit spread for non-performance risk (U) 0.2% 0.2% Internal model Risk cost of capital (U) 5.1% 5.0% Internal model Weighted average cost of capital (U) 8.5% 8.5% Internal model Duration - liability (U) 7.82 years 7.33 years Internal model Duration - reinsurance balances recoverable on paid and unpaid losses (U) 8.68 years 7.98 years The fair value of the liability for losses and LAE and reinsurance balances recoverable on paid and unpaid losses may increase or decrease due to changes in the corporate bond rate, the credit spread for non-performance risk, the risk cost of capital, the weighted average cost of capital and the estimated payment pattern as described below: • An increase in the corporate bond rate or credit spread for non-performance risk would result in a decrease in the fair value of the liability for losses and LAE and reinsurance balances recoverable on paid and unpaid losses. Conversely, a decrease in the corporate bond rate or credit spread for non-performance risk would result in an increase in the fair value of the liability for losses and LAE and reinsurance balances recoverable on paid and unpaid losses. • An increase in the weighted average cost of capital would result in an increase in the fair value of the liability for losses and LAE and reinsurance balances recoverable on paid and unpaid losses . Conversely, a decrease in the weighted average cost of capital would result in a decrease in the fair value of the liability for losses and LAE and reinsurance balances recoverable on paid and unpaid losses. • An increase in the risk cost of capital would result in an increase in the fair value of the liability for losses and LAE and reinsurance balances recoverable on paid and unpaid losses. Conversely, a decrease in the risk cost of capital would result in a decrease in the fair value of the liability for losses and LAE and reinsurance balances recoverable on paid and unpaid losses. • The duration of the liability and recoverable is adjusted every period to reflect actual net payments during the period and expected future payments. An acceleration of the estimated payment pattern, a decrease in duration, would result in an increase in the fair value of the liability for losses and LAE and reinsurance balances recoverable on paid and unpaid losses. Conversely, a deceleration of the estimated payment pattern, an increase in duration, would result in a decrease in the fair value of the liability for losses and LAE and reinsurance balances recoverable on paid and unpaid losses. In addition, the estimate of the capital required to support the liabilities is based upon current industry standards for capital adequacy. If the required capital per unit of risk increases, then the fair value of the liability for losses and LAE and reinsurance balances recoverable on paid and unpaid losses would increase. Conversely, a decrease in required capital would result in a decrease in the fair value of the liability for losses and LAE and reinsurance balances recoverable on paid and unpaid losses. Disclosure of Fair Values for Financial Instruments Carried at Cost Senior Notes As of December 31, 2019 , our 4.50% Senior Notes due 2022 (the "2022 Senior Notes") and our 4.95% Senior Notes due 2029 (the "2029 Senior Notes" and, together with the 2022 Senior Notes, the "Senior Notes") were carried at amortized cost of $348.6 million and $493.6 million , respectively, while the fair value based on observable market pricing from a third party pricing service was $362.5 million and $537.4 million , respectively. The Senior Notes are classified as Level 2. Insurance Contracts Disclosure of fair value of amounts relating to insurance contracts is not required, except those for which we elected the fair value option, as described above. Remaining Assets and Liabilities Our remaining assets and liabilities were generally carried at cost or amortized cost, which due to their short-term nature approximates fair value as of December 31, 2019 and 2018 .

Premiums Written and Earned

Premiums Written and Earned	12 Months Ended
	Dec. 31, 2019
Insurance [Abstract]
PREMIUMS WRITTEN AND EARNED	$1 million 551,636 7,761 233,871 793,268 33.4 % 364,098 12,091 220,123 596,312 29.4 % Other reinsurers < $1 million 19,243 545 2,502 22,290 0.9 % 16,211 1,182 3,448 20,841 1.0 % Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 100.0 % $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 100.0 % December 31, 2019 December 31, 2018 Information regarding top ten reinsurers: Number of top 10 reinsurers rated A- or better 8 7 Number of top 10 non-rated reinsurers (1) 2 3 Recoverables rated A- or better in top 10 $ 1,292,207 $ 1,096,272 Collaterized non-rated reinsurers recoverables in top 10 (1) 272,125 316,238 $ 1,564,332 $ 1,412,510 Single reinsurers that represent 10% or more of total reinsurance balance recoverables as of December 31, 2019: Hannover Ruck SE (2) $ 261,295 $ 279,723 Lloyd's Syndicates (3) $ 411,030 $ 334,509 (1) For the two non-rated reinsurers as of December 31, 2019 and three non-rated reinsurers as at December 31, 2018 , we hold security in the form of pledged assets in trust or letters of credit issued to us in the full amount of the recoverable. (2) Hannover Ruck SE is rated AA- by Standard & Poor’s and A+ by A.M. Best. (3) Lloyd's Syndicates are rated A+ by Standard & Poor's and A by A.M. Best. Provisions for Uncollectible Reinsurance Balances Recoverable on Paid and Unpaid Losses We evaluate and monitor concentration of credit risk among our reinsurers. Provisions are made for amounts considered potentially uncollectible. The following table shows our reinsurance balances recoverable on paid and unpaid losses by rating of reinsurer and our provisions for uncollectible reinsurance balances recoverable on paid and unpaid losses ("provisions for bad debt") as of December 31, 2019 and 2018 . The majority of the provisions for bad debt relate to the Non-life Run-off segment. 2019 2018 Gross Provisions for Bad Debt Net Provisions as a Gross Provisions for Bad Debt Net Provisions as a Reinsurers rated A- or above $ 1,904,268 $ 43,427 $ 1,860,841 2.3 % $ 1,612,464 $ 51,519 $ 1,560,945 3.2 % Reinsurers rated below A-, secured 487,608 — 487,608 — % 430,852 — 430,852 — % Reinsurers rated below A-, unsecured 135,653 104,212 31,441 76.8 % 143,079 105,213 37,866 73.5 % Total $ 2,527,529 $ 147,639 $ 2,379,890 5.8 % $ 2,186,395 $ 156,732 $ 2,029,663 7.2 % 13. PREMIUMS WRITTEN AND EARNED The following tables provide a summary of net premiums written and earned for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Premiums Written Premiums Earned Premiums Written Premiums Earned Premiums Written Premiums Earned Non-life Run-off Gross $ (25,069 ) $ 197,009 $ (8,910 ) $ 25,230 $ 14,102 $ 23,950 Ceded (269 ) (28,513 ) (307 ) (15,803 ) (7,620 ) (9,788 ) Net $ (25,338 ) $ 168,496 $ (9,217 ) $ 9,427 $ 6,482 $ 14,162 Atrium Gross $ 192,373 $ 182,678 $ 171,494 $ 164,428 $ 153,472 $ 152,278 Ceded (20,017 ) (18,619 ) (18,006 ) (18,113 ) (19,258 ) (17,531 ) Net $ 172,356 $ 164,059 $ 153,488 $ 146,315 $ 134,214 $ 134,747 StarStone Gross $ 917,555 $ 1,021,827 $ 1,121,135 $ 1,010,816 $ 895,160 $ 865,159 Ceded (182,126 ) (219,901 ) (315,573 ) (295,857 ) (430,259 ) (405,756 ) Net $ 735,429 $ 801,926 $ 805,562 $ 714,959 $ 464,901 $ 459,403 Other Gross $ 18,534 $ 20,544 $ 32,378 $ 25,237 $ 5,719 $ 5,900 Ceded (22 ) (164 ) (311 ) (363 ) (926 ) (1,091 ) Net $ 18,512 $ 20,380 $ 32,067 $ 24,874 $ 4,793 $ 4,809 Total Gross $ 1,103,393 $ 1,422,058 $ 1,316,097 $ 1,225,711 $ 1,068,453 $ 1,047,287 Ceded (202,434 ) (267,197 ) (334,197 ) (330,136 ) (458,063 ) (434,166 ) Net $ 900,959 $ 1,154,861 $ 981,900 $ 895,575 $ 610,390 $ 613,121 Gross premiums written for the year ended December 31, 2019 and 2018 were $1,103.4 million and $1,316.1 million , respectively, a decrease of $212.7 million . The decrease was primarily due to a decrease in gross written premiums in our StarStone segment due to our strategy to exit certain lines of business, and reductions in gross written premiums in our Non-life Run-off segment due to unearned premium acquired in various transactions." id="sjs-B4">8. REINSURANCE BALANCES RECOVERABLE ON PAID AND UNPAID LOSSES The following table provides the total reinsurance balances recoverable on paid and unpaid losses as of December 31, 2019 and 2018 : 2019 Non-life Run-off Atrium StarStone Total Recoverable from reinsurers on unpaid: Outstanding losses $ 972,293 $ 9,011 $ 328,009 $ 1,309,313 IBNR 673,059 19,286 211,404 903,749 Fair value adjustments - acquired companies (13,652 ) 519 (2,122 ) (15,255 ) Fair value adjustments - fair value option (88,086 ) — — (88,086 ) Total reinsurance reserves recoverable 1,543,614 28,816 537,291 2,109,721 Paid losses recoverable 181,375 1,541 87,253 270,169 Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 Reconciliation to Consolidated Balance Sheet: Reinsurance balances recoverable on paid and unpaid losses $ 1,029,471 $ 30,357 $ 624,544 $ 1,684,372 Reinsurance balances recoverable on paid and unpaid losses - fair value option 695,518 — — 695,518 Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 2018 Non-life Run-off Atrium StarStone Total Recoverable from reinsurers on unpaid: Outstanding losses $ 901,772 $ 18,891 $ 263,065 $ 1,183,728 IBNR 609,434 19,247 201,784 830,465 Fair value adjustments - acquired companies (14,344 ) 630 (1,899 ) (15,613 ) Fair value adjustments - fair value option (130,739 ) — — (130,739 ) Total reinsurance reserves recoverable 1,366,123 38,768 462,950 1,867,841 Paid losses recoverable 138,265 (256 ) 23,813 161,822 Total $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 Reconciliation to Consolidated Balance Sheet: Reinsurance balances recoverable on paid and unpaid losses $ 764,797 $ 38,512 $ 486,763 $ 1,290,072 Reinsurance balances recoverable on paid and unpaid losses - fair value option 739,591 — — 739,591 Total $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 Our insurance and reinsurance run-off subsidiaries and assumed portfolios, prior to acquisition, used retrocessional agreements to reduce their exposure to the risk of insurance and reinsurance assumed. On an annual basis, both Atrium and StarStone purchase a tailored outwards reinsurance program designed to manage their risk profiles. The majority of Atrium’s and StarStone's third-party reinsurance cover is with highly rated reinsurers or is collateralized by pledged assets or letters of credit. The fair value adjustments, determined on acquisition of insurance and reinsurance subsidiaries, are based on the estimated timing of loss and LAE recoveries and an assumed interest rate equivalent to a risk free rate for securities with similar duration to the acquired reinsurance balances recoverable on paid and unpaid losses plus a spread to reflect credit risk, and are amortized over the estimated recovery period, as adjusted for accelerations in timing of payments as a result of commutation settlements. The determination of the fair value adjustments on the retroactive reinsurance contracts for which we have elected the fair value option is described in Note 12 - "Fair Value Measurements" . As of December 31, 2019 and 2018 , we had reinsurance balances recoverable on paid and unpaid losses of approximately $2,379.9 million and $2,029.7 million , respectively. The increase of $350.2 million in reinsurance balances recoverable on paid and unpaid losses was primarily due to the AmTrust RITC and Zurich reinsurance transactions, which closed during the first and fourth quarters of 2019, respectively, and reserve increases in StarStone and our non-life run-off segment, offset by commutations and cash collections made during the year ended December 31, 2019 . Top Ten Reinsurers December 31, 2019 December 31, 2018 Non-life Atrium StarStone Total % of Non-life Atrium StarStone Total % of Top ten reinsurers $ 1,154,110 $ 22,051 $ 388,171 $ 1,564,332 65.7 % $ 1,124,079 $ 25,239 $ 263,192 $ 1,412,510 69.6 % Other reinsurers > $1 million 551,636 7,761 233,871 793,268 33.4 % 364,098 12,091 220,123 596,312 29.4 % Other reinsurers < $1 million 19,243 545 2,502 22,290 0.9 % 16,211 1,182 3,448 20,841 1.0 % Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 100.0 % $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 100.0 % December 31, 2019 December 31, 2018 Information regarding top ten reinsurers: Number of top 10 reinsurers rated A- or better 8 7 Number of top 10 non-rated reinsurers (1) 2 3 Recoverables rated A- or better in top 10 $ 1,292,207 $ 1,096,272 Collaterized non-rated reinsurers recoverables in top 10 (1) 272,125 316,238 $ 1,564,332 $ 1,412,510 Single reinsurers that represent 10% or more of total reinsurance balance recoverables as of December 31, 2019: Hannover Ruck SE (2) $ 261,295 $ 279,723 Lloyd's Syndicates (3) $ 411,030 $ 334,509 (1) For the two non-rated reinsurers as of December 31, 2019 and three non-rated reinsurers as at December 31, 2018 , we hold security in the form of pledged assets in trust or letters of credit issued to us in the full amount of the recoverable. (2) Hannover Ruck SE is rated AA- by Standard & Poor’s and A+ by A.M. Best. (3) Lloyd's Syndicates are rated A+ by Standard & Poor's and A by A.M. Best. Provisions for Uncollectible Reinsurance Balances Recoverable on Paid and Unpaid Losses We evaluate and monitor concentration of credit risk among our reinsurers. Provisions are made for amounts considered potentially uncollectible. The following table shows our reinsurance balances recoverable on paid and unpaid losses by rating of reinsurer and our provisions for uncollectible reinsurance balances recoverable on paid and unpaid losses ("provisions for bad debt") as of December 31, 2019 and 2018 . The majority of the provisions for bad debt relate to the Non-life Run-off segment. 2019 2018 Gross Provisions for Bad Debt Net Provisions as a Gross Provisions for Bad Debt Net Provisions as a Reinsurers rated A- or above $ 1,904,268 $ 43,427 $ 1,860,841 2.3 % $ 1,612,464 $ 51,519 $ 1,560,945 3.2 % Reinsurers rated below A-, secured 487,608 — 487,608 — % 430,852 — 430,852 — % Reinsurers rated below A-, unsecured 135,653 104,212 31,441 76.8 % 143,079 105,213 37,866 73.5 % Total $ 2,527,529 $ 147,639 $ 2,379,890 5.8 % $ 2,186,395 $ 156,732 $ 2,029,663 7.2 % 13. PREMIUMS WRITTEN AND EARNED The following tables provide a summary of net premiums written and earned for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Premiums Written Premiums Earned Premiums Written Premiums Earned Premiums Written Premiums Earned Non-life Run-off Gross $ (25,069 ) $ 197,009 $ (8,910 ) $ 25,230 $ 14,102 $ 23,950 Ceded (269 ) (28,513 ) (307 ) (15,803 ) (7,620 ) (9,788 ) Net $ (25,338 ) $ 168,496 $ (9,217 ) $ 9,427 $ 6,482 $ 14,162 Atrium Gross $ 192,373 $ 182,678 $ 171,494 $ 164,428 $ 153,472 $ 152,278 Ceded (20,017 ) (18,619 ) (18,006 ) (18,113 ) (19,258 ) (17,531 ) Net $ 172,356 $ 164,059 $ 153,488 $ 146,315 $ 134,214 $ 134,747 StarStone Gross $ 917,555 $ 1,021,827 $ 1,121,135 $ 1,010,816 $ 895,160 $ 865,159 Ceded (182,126 ) (219,901 ) (315,573 ) (295,857 ) (430,259 ) (405,756 ) Net $ 735,429 $ 801,926 $ 805,562 $ 714,959 $ 464,901 $ 459,403 Other Gross $ 18,534 $ 20,544 $ 32,378 $ 25,237 $ 5,719 $ 5,900 Ceded (22 ) (164 ) (311 ) (363 ) (926 ) (1,091 ) Net $ 18,512 $ 20,380 $ 32,067 $ 24,874 $ 4,793 $ 4,809 Total Gross $ 1,103,393 $ 1,422,058 $ 1,316,097 $ 1,225,711 $ 1,068,453 $ 1,047,287 Ceded (202,434 ) (267,197 ) (334,197 ) (330,136 ) (458,063 ) (434,166 ) Net $ 900,959 $ 1,154,861 $ 981,900 $ 895,575 $ 610,390 $ 613,121 Gross premiums written for the year ended December 31, 2019 and 2018 were $1,103.4 million and $1,316.1 million , respectively, a decrease of $212.7 million . The decrease was primarily due to a decrease in gross written premiums in our StarStone segment due to our strategy to exit certain lines of business, and reductions in gross written premiums in our Non-life Run-off segment due to unearned premium acquired in various transactions.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	14. GOODWILL AND INTANGIBLE ASSETS The following table presents a reconciliation of the beginning and ending goodwill and intangible assets for the years ended December 31, 2019 and 2018 : Intangible assets Goodwill Intangible assets with a definite life Intangible assets with an indefinite life Total Total Balance as of December 31, 2017 $ 73,071 $ 20,487 $ 87,031 $ 107,518 $ 180,589 Acquired during the year 41,736 — — — 41,736 Amortization — (3,600 ) — (3,600 ) (3,600 ) Balance as of December 31, 2018 $ 114,807 $ 16,887 $ 87,031 $ 103,918 $ 218,725 Amortization — (2,257 ) — (2,257 ) (2,257 ) Balance as of December 31, 2019 $ 114,807 $ 14,630 $ 87,031 $ 101,661 $ 216,468 Goodwill Goodwill as of December 31, 2019 and 2018 , related to our Non-life Run-off, Atrium and StarStone segments, was as follows: 2019 2018 Non-life Run-Off $ 62,959 $ 62,959 Atrium 38,848 38,848 StarStone 13,000 13,000 $ 114,807 $ 114,807 For the year ended December 31, 2019 , we completed our assessment for impairment of goodwill and concluded that there had been no impairment of our carried goodwill amount. For the year ended December 31, 2018 the increase in the goodwill balance in the Non-life Run-off segment was due to the acquisition of KaylaRe as discussed in Note 3 - "Acquisitions" , which resulted in the recognition of goodwill of $41.7 million , none of which is amortizable for tax purposes. Intangible Assets Intangible assets with a definite life includes the distribution channel, technology and brand related to our acquisitions of Atrium and StarStone. These assets are amortized on a straight-line basis over a period ranging from four to fifteen years. The following table provides a summary of the amortization recorded on the intangible assets for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Intangible asset amortization $ 2,257 $ 3,600 $ 4,266 Intangible assets with an indefinite life includes assets associated with the Lloyd’s syndicate capacity for StarStone and Atrium, StarStone's U.S. insurance licenses, and Atrium’s management contract with Syndicate 609 in relation to underwriting, actuarial and support services it provides. The gross carrying value, accumulated amortization and net carrying value of intangible assets by type as of December 31, 2019 and 2018 was as follows: 2019 2018 Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value Intangible assets with a definite life: Distribution channel $ 20,000 $ (8,111 ) $ 11,889 $ 20,000 $ (6,776 ) $ 13,224 Technology 15,000 (15,000 ) — 15,000 (14,778 ) 222 Brand 7,000 (4,259 ) 2,741 7,000 (3,559 ) 3,441 Total $ 42,000 $ (27,370 ) $ 14,630 $ 42,000 $ (25,113 ) $ 16,887 Intangible assets with an indefinite life: Lloyd’s syndicate capacity $ 37,031 $ — $ 37,031 $ 37,031 $ — $ 37,031 Licenses 19,900 — 19,900 19,900 — 19,900 Management contract 30,100 — 30,100 30,100 — 30,100 Total $ 87,031 $ — $ 87,031 $ 87,031 $ — $ 87,031 The net carrying value of intangible assets by segment and by type as of December 31, 2019 and 2018 was as follows: 2019 2018 Atrium StarStone Total Atrium StarStone Total Intangible assets with a definite life: Distribution channel $ 11,889 $ — $ 11,889 $ 13,224 $ — $ 13,224 Technology — — — — 222 222 Brand 2,741 — 2,741 3,441 — 3,441 Total $ 14,630 $ — $ 14,630 $ 16,665 $ 222 $ 16,887 Intangible assets with an indefinite life: Lloyd’s syndicate capacity $ 33,031 $ 4,000 $ 37,031 $ 33,031 $ 4,000 $ 37,031 Licenses — 19,900 19,900 — 19,900 19,900 Management contract 30,100 — 30,100 30,100 — 30,100 Total $ 63,131 $ 23,900 $ 87,031 $ 63,131 $ 23,900 $ 87,031 Total intangible assets $ 77,761 $ 23,900 $ 101,661 $ 79,796 $ 24,122 $ 103,918 The estimated future amortization expense related to our intangible assets with a definite life is as follows: Year Atrium StarStone Total 2020 $ 2,033 $ — $ 2,033 2021 2,033 — 2,033 2022 2,033 — 2,033 2023 1,975 — 1,975 2024 1,333 — 1,333 2025 and thereafter 5,223 — 5,223 Total amortization $ 14,630 $ — $ 14,630

Debt Obligations and Credit Fac

Debt Obligations and Credit Facilities	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt Obligations and Credit Facilities	15. DEBT OBLIGATIONS AND CREDIT FACILITIES We primarily utilize debt facilities for funding acquisitions and significant new business, investment activities and, from time to time, for general corporate purposes. Our debt obligations are as follows: Facility Origination Date Term December 31, December 31, 4.50% Senior Notes due 2022 March 10, 2017 5 years $ 348,616 $ 348,054 4.95% Senior Notes due 2029 May 28, 2019 10 years 493,600 — Total senior notes 842,216 348,054 EGL Revolving Credit Facility August 16, 2018 5 years — 15,000 2018 EGL Term Loan Facility December 27, 2018 3 years 348,991 498,485 Total debt obligations $ 1,191,207 $ 861,539 During the year ended December 31, 2019 , we utilized $1,070.5 million and repaid $742.6 million under our facilities. The facilities were primarily utilized for funding acquisitions as described in Note 3 - "Acquisitions" , significant new business as described in Note 4 - "Significant New Business" , and investing activities. The table below provides a summary of the total interest expense for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Interest expense on debt obligations $ 51,245 $ 25,205 $ 25,619 Amortization of debt issuance costs 953 537 416 Funds withheld balances and other 343 475 2,067 Total interest expense $ 52,541 $ 26,217 $ 28,102 Senior Notes 4.50% Senior Notes due 2022 On March 10, 2017, we issued the 2022 Senior Notes for an aggregate principal amount of $350.0 million . The 2022 Senior Notes pay 4.5% interest semi-annually and mature on March 10, 2022. The 2022 Senior Notes are unsecured and unsubordinated obligations that rank equal to any of our other unsecured and unsubordinated obligations, senior to any future obligations that are expressly subordinated to the 2022 Senior Notes, effectively subordinate to any of our secured indebtedness to the extent of the value of the assets securing such indebtedness, and structurally subordinate to all liabilities of our subsidiaries. The 2022 Senior Notes are rated BBB- and are redeemable at our option on a make whole basis at any time prior to the date that is one month prior to the maturity of the 2022 Senior Notes. On or after the date that is one month prior to the maturity of the 2022 Senior Notes, the notes are redeemable at a redemption price equal to 100% of the principal amount of the 2022 Senior Notes to be redeemed. We incurred costs of $2.9 million in issuing the 2022 Senior Notes. These costs included underwriters’ fees, legal and accounting fees, and other fees, and are capitalized and presented as a direct deduction from the principal amount of debt obligations in the consolidated balance sheets. These costs are amortized over the term of the 2022 Senior Notes and are included in interest expense in our consolidated statements of earnings. The unamortized costs as of December 31, 2019 and 2018 were $1.4 million and $1.9 million , respectively. 4.95% Senior Notes due 2029 On May 28, 2019 , we issued the 2029 Senior Notes for an aggregate principal amount of $500.0 million . The 2029 Senior Notes pay 4.95% interest semi-annually and mature on June 1, 2029. The 2029 Senior Notes are unsecured and unsubordinated obligations that rank equal to any of our other unsecured and unsubordinated obligations, senior to any future obligations that are expressly subordinated to the 2029 Senior Notes, effectively subordinate to any of our secured indebtedness to the extent of the value of the assets securing such indebtedness, and contractually subordinate to all liabilities of our subsidiaries. The 2029 Senior Notes are rated BBB- and are redeemable at our option on a make whole basis at any time prior to the date that is three months prior to the maturity of the 2029 Senior Notes. On or after the date that is three months prior to the maturity of the 2029 Senior Notes, the notes are redeemable at a redemption price equal to 100% of the principal amount of the notes to be redeemed. We incurred costs of $6.8 million in issuing the 2029 Senior Notes. These costs included underwriters’ fees, legal and accounting fees, and other fees, and are capitalized and presented as a direct deduction from the principal amount of debt obligations in the consolidated balance sheets. These costs are amortized over the term of the 2029 Senior Notes and are included in interest expense in our consolidated statements of earnings. The unamortized costs as of December 31, 2019 were $6.4 million . EGL Revolving Credit Facility On August 16, 2018, we and certain of our subsidiaries, as borrowers and guarantors, entered into a new five -year unsecured $600.0 million revolving credit agreement. The revolving credit agreement expires in August 2023 and we have the option to increase the commitments under the facility by up to an aggregate amount of $400.0 million from the existing lenders, or through the addition of new lenders subject to the terms of the agreement. Borrowings under the facility will bear interest at a rate based on the Company's long term senior unsecured debt ratings. As of December 31, 2019 , we were permitted to borrow up to an aggregate of $600.0 million under the facility. As of December 31, 2019 , there was $600.0 million of available unutilized capacity under the facility. Subsequent to December 31, 2019 , we drew down $5.0 million bringing the unutilized capacity under this facility to $595.0 million . Interest is payable at least every three months at either the alternate base rate ("ABR") or LIBOR plus a margin as set forth in the revolving credit agreement. The margin could vary based upon any change in our long term senior unsecured debt rating assigned by S&P or Fitch. We also pay a commitment fee based on the average daily unutilized portion of the facility. If an event of default occurs, the interest rate may increase and the agent may, and at the request of the required lenders shall, cancel lender commitments and demand early repayment. Financial and business covenants imposed on us in relation to the new revolving credit facility include certain limitations on mergers and consolidations, acquisitions, indebtedness and guarantees, restrictions as to dispositions of stock and assets, and limitations on liens. Generally, the financial covenants require us to maintain a gearing ratio of consolidated indebtedness to total capitalization of not greater than 0.35 to 1.0 and to maintain a consolidated net worth of not less than the aggregate of (i) $2.3 billion , (ii) 50% of net income available for distribution to our ordinary shareholders at any time after August 16, 2018, and (iii) 50% of the proceeds of any common stock issuance made after August 16, 2018. In addition, we must maintain eligible capital in excess of the enhanced capital requirement imposed on us by the Bermuda Monetary Authority pursuant to the Insurance (Group Supervision) Rules 2011 of Bermuda. We are in compl iance with the covenants of the EGL Revolving Credit Facility. 2018 EGL Term Loan Facility On December 27, 2018 , we entered into and fully utilized a three -year $500.0 million unsecured term loan (the "2018 EGL Term Loan Facility"). The proceeds were partially used to fund the acquisition of Maiden Re North America. We have the option to increase the principal amount of the term loan credit facility up to an aggregate amount of $150.0 million from the existing lenders or through the addition of new lenders, subject to the terms of the term loan credit agreement. During 2019, we repaid $150.0 million of principal on the facility, bringing the outstanding loan amount to $349.0 million , which includes unamortized issuance costs of $1.0 million , as of December 31, 2019 . Interest is payable at least every three months at either ABR or LIBOR plus a margin set forth in the term loan credit agreement. The margin could vary based upon any change in our long term senior unsecured debt rating assigned by S&P or Fitch. During the existence of an event of default, the interest rate may increase and the agent may, and at the request of the required lenders shall, demand early repayment. Financial and business covenants relating to this facility are similar to the EGL revolving credit facility. We are in compliance with the covenants of the 2018 EGL Term Loan Facility. We incurred costs of $1.5 million associated with closing the 2018 EGL Term Loan Facility. These costs included bank, legal and accounting fees, and other fees, and are capitalized and presented as a direct deduction from the principal amount of debt obligations in the consolidated balance sheets. These costs are amortized over the term of the facility and are included in interest expense in our consolidated statements of earnings. The unamortized costs as of December 31, 2019 and December 31, 2018 were $1.0 million and $1.5 million , respectively. Unsecured Letters of Credit We utilize unsecured letters of credit to support certain of our insurance and reinsurance performance obligations. Funds at Lloyd's We have an unsecured letter of credit agreement for Funds at Lloyd's ("FAL Facility") to issue up to $375.0 million of letters of credit, with provision to increase the facility by an additional $25.0 million up to an aggregate amount of $400.0 million , subject to lenders approval. On November 6, 2019, we amended and restated the FAL Facility to extend its term by one year . The FAL Facility is available to satisfy our Funds at Lloyd's requirements and expires in 2023. As of December 31, 2019 , our combined Funds at Lloyd's were comprised of cash and investments of $639.3 million and unsecured letters of credit of $252.0 million . $120.0 million Letter of Credit Facility We use this facility to support certain reinsurance collateral obligations of our subsidiaries. On December 6, 2019, we reduced the facility size from $170.0 million to $120.0 million . Pursuant to the facility agreement, we have the option to increase commitments under the facility by an additional $60.0 million . As of December 31, 2019 and December 31, 2018 , we had issued an aggregate amount of letters of credit under this facility of $115.3 million and $78.4 million , respectively. $760.0 million Syndicated Letter of Credit Facility During 2019, we entered into an unsecured $760.0 million letter of credit facility agreement, most recently amended on December 9, 2019. We may increase the commitments by an aggregate amount of $40.0 million . The facility is used to post letters of credit to collateralize reinsurance performance obligations to various parties, including $445.0 million relating to the reinsurance transaction with Maiden Re Bermuda, as described in Note 4 - "Significant New Business" . As of December 31, 2019 , we had issued an aggregate amount of letters of credit under this facility of $608.0 million

Noncontrolling Interest

Noncontrolling Interest	12 Months Ended
	Dec. 31, 2019
Noncontrolling Interest [Abstract]
Noncontrolling Interest	16. NONCONTROLLING INTEREST We have both redeemable noncontrolling interest and noncontrolling interest on our consolidated balance sheets. Redeemable noncontrolling interest with redemption features that are not solely within our control are classified within temporary equity in the consolidated balance sheets and carried at redemption value, which is fair value. The change in fair value is recognized through retained earnings as if the balance sheet date were also the redemption date. In addition, we also have noncontrolling interest, which does not have redemption features and is classified within equity in the consolidated balance sheets. Redeemable Noncontrolling Interest Redeemable noncontrolling interest ("RNCI") as of December 31, 2019 and 2018 comprises the ownership interests held by the Trident V Funds ("Trident") ( 39.3% ) and Dowling Capital Partners, L.P. ("Dowling") ( 1.7% ) in our subsidiary North Bay Holdings Limited ("North Bay"). North Bay owns our investments in Atrium and StarStone. The following is a reconciliation of the beginning and ending carrying amount of the equity attributable to the RNCI for the years ended December 31, 2019 and 2018 : 2019 2018 Balance at beginning of year $ 458,543 $ 479,606 Capital contributions 13,127 55,377 Dividends paid (11,556 ) (3,852 ) Net loss attributable to RNCI (12,029 ) (64,794 ) Accumulated other comprehensive income (loss) attributable to RNCI (116 ) (240 ) Change in redemption value of RNCI (9,178 ) (7,554 ) Balance at end of year $ 438,791 $ 458,543 We carried the RNCI at its estimated redemption value, which is fair value, as of December 31, 2019 . The fair value is based on tangible book value and a valuation multiple derived from a combination of comparable company market valuations, recent comparable transaction multiples and discounted cash flow models. The decrease in the fair value of the RNCI during 2019 was primarily attributable to a decrease in tangible net assets due to net losses relating to StarStone during 2019 and the distribution of Atrium dividends during the year ended December 31, 2019 , which were partially offset by net earnings from Atrium. The valuation multiples did not change significantly. Refer to Note 2 - "Significant Accounting Policies" , Note 21 - "Related Party Transactions" and Note 23 - "Commitments and Contingencies" Noncontrolling Interest As of December 31, 2019 and 2018 , we had $14.2 million and $12.1 million

Share Capital

Share Capital	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Share Capital	17. SHARE CAPITAL As of December 31, 2019 and 2018 , the authorized share capital was 111,000,000 ordinary shares ("Voting Ordinary Shares") and non-voting convertible ordinary shares ("Non-Voting Ordinary Shares"), each of par value $1.00 per share, and 45,000,000 preferred shares of par value $1.00 per share. Voting Ordinary Shares Our Voting Ordinary Shares are listed and trade on the NASDAQ Global Select Market. Each Voting Ordinary Share entitles the holder thereof to one vote. On May 14, 2018 , 1,501,778 Voting Ordinary Shares were issued as consideration for the acquisition of KaylaRe Holdings Ltd, as described in Note 3 - "Acquisitions" . On January 21, 2020, 565,630 Voting Ordinary Shares were issued to the trustee of the Enstar Group Limited Employee Benefit Trust (the "EB Trust"). Shares held in the EB Trust are classified as treasury shares. The EB Trust supports awards made under the Joint Share Ownership Plan, a sub-plan to our Amended and Restated 2016 Equity Incentive Plan (the "JSOP"). Voting rights in respect of shares held in the EB Trust have been contractually waived. Non-Voting Ordinary Shares The Non-Votin g Ordinary Shares are comprised of several different series as of December 31, 2019 • the Series A shares were canceled in June 2016 in an internal reorganization as described below. • the Series C shares were originally issued in connection with investment transactions in April and December of 2011. In addition, there were 66,520 Series C Non-Voting Ordinary Shares issued in March 2017 in connection with the exercise of warrants as described below. The Series C shares: (i) have all of the economic rights (including dividend rights) attaching to Voting Ordinary Shares but are non-voting except in certain limited circumstances; (ii) will automatically convert at a one -for-one exchange ratio (subject to adjustment for share splits, dividends, recapitalizations, consolidations or similar transactions) into Voting Ordinary Shares if the registered holder transfers them in a widely dispersed offering; (iii) may only vote on certain limited matters that would constitute a variation of class rights and as required under Bermuda law, provided that the aggregate voting power of the Series C shares with respect to any merger, consolidation or amalgamation will not exceed 0.01% of the aggregate voting power of our issued share capital; and (iv) require the registered holders’ written consent in order to vary the rights of the shares in a significant and adverse manner. During the three months ended March 31, 2017, 192,485 • the Series B and Series D shares were created in connection with the 2011 investment transactions, but no shares in these series are issued and outstanding. Holders of the Series C shares have the right to convert such shares, on a share-for-share basis, subject to certain adjustments, into Series D shares at their option. There is no economic difference in Series B, C or D shares, but there are slight differences in the conversion rights and the limited voting rights of each series. • there were 910,010 Series E shares issued and outstanding as of December 31, 2019 . On May 14, 2018 , 505,239 Series E non-voting shares were issued as consideration for the acquisition of KaylaRe Holdings Ltd, as described in Note 3 - "Acquisitions" . The Series E shares have substantially the same rights as the Series C shares, except that (i) they are convertible only into Voting Ordinary Shares and (ii) they may only vote as required under Bermuda law. The Series E shares include all other Non-Voting Ordinary Shares authorized under our bye-laws but not classified as Series A, B, C or D Non-Voting Ordinary Shares. Warrants As of December 31, 2019 , there were warrants outstanding to acquire 175,901 Series C Non-Voting Ordinary Shares for an exercise price of $115.00 Series C Preferred Shares As of December 31, 2019 , there were 388,571 Series C Participating Non-Voting Perpetual Preferred Shares ("Series C Preferred Shares") issued and held by one of our wholly-owned subsidiaries. The Series C Preferred Shares were issued in June 2016 in an internal reorganization transaction that resulted in the cancellation of all of the Series A Shares. The Series C Preferred Shares (i) upon liquidation, dissolution or winding up of the Company, entitle their holders to a preference over holders of our ordinary voting and non-voting shares of an amount equal to $0.001 per share with respect to surplus assets and (ii) are non-voting except in certain limited circumstances. The Series C Preferred shares have dividend rights equal to those of the ordinary voting shares, subject to certain limitations and in an amount determined by a "participation rate" that is generally reflective of the reduction in the number of Series C Preferred Shares issued in exchange for the previously outstanding Series A Shares. The Series C Preferred Shares otherwise rank on parity with the ordinary voting and non-voting shares, and they rank senior to each other class or series of share capital, unless the terms of any such class or series shall expressly provide otherwise. Series D Preferred Shares On June 28, 2018 , the Company raised $400.0 million of gross proceeds through the public offering of 16,000 shares of its 7.00% non-cumulative fixed-to-floating rate Series D perpetual preferred shares ("Series D Preferred Shares") (equivalent to 16,000,000 depositary shares, each of which represents a 1/1,000th interest in a Series D Preferred Share), $1.00 par value and $25,000 liquidation preference (the "Liquidation Preference") per share (equivalent to $25.00 per depositary share). The Company received net proceeds of $389.2 million which was used to repay debt obligations. The depositary shares are listed and trade on the NASDAQ Global Select Market. The Series D Preferred Shares are not redeemable prior to September 1, 2028 , except in specified circumstances relating to certain tax, corporate, capital or rating agency events as described in the prospectus supplement relating to the offering. On and after September 1, 2028 , the Series D Preferred Shares, represented by the depositary shares, will be redeemable at the Company’s option, in whole or from time to time in part, at a redemption price equal to $25,000 per Series D Preferred Share (equivalent to $25.00 Series E Preferred Shares On November 21, 2018 , the Company raised $110.0 million of gross proceeds through the public offering of 4,400 shares of its 7.00% fixed rate non-cumulative Series E perpetual preferred shares ("Series E Preferred Shares") (equivalent to 4,400,000 depositary shares, each of which represents a 1/1,000th interest in a Series E Preferred Share), $1.00 par value and $25,000 liquidation preference (the "Series E Liquidation Preference") per share (equivalent to $25.00 per depositary share). The Company received net proceeds of $106.1 million which was used to fund operations within our Non-life Run-off segment. The depositary shares are listed and trade on the NASDAQ Global Select Market. The Series E Preferred Shares are not redeemable prior to March 1, 2024 , except in specified circumstances relating to certain tax, corporate, capital or rating agency events as described in the prospectus supplement relating to the offering. On and after March 1, 2024 , the Series E Preferred Shares, represented by the depositary shares, will be redeemable at the Company’s option, in whole or from time to time in part, at a redemption price equal to $25,000 per Series E Preferred Share (equivalent to $25.00 Dividends on Preferred Shares Holders of Series D and Series E Preferred Shares are entitled to receive, only when, as and if declared, non-cumulative cash dividends, paid quarterly in arrears on the 1st day of March, June, September and December of each year, commencing on September 1, 2018 for the Series D Preferred Shares and March 1, 2019 for the Series E Preferred Shares, of 7.00% per annum. Commencing on September 1, 2028 , the Series D Preferred Shares will convert to a floating rate basis and dividends will be payable on a non-cumulative basis, when, as and if declared, at three-month LIBOR plus 4.015% per annum. Dividends that are not declared will not accumulate and will not be payable. During 2019 , we declared and paid $28.0 million of dividends on the Series D Preferred Shares, and declared and paid $7.9 million of dividends on the Series E Preferred Shares. During 2018 , we declared and paid $12.1 million of dividends on the Series D Preferred Shares. During February 2020 , we declared $7.0 million and $1.9 million of dividends on the Series D and E Preferred Shares, respectively, to be paid on March 2, 2020 to shareholders of record as of February 15, 2020 . Any payment of dividends must be approved by our Board of Directors. Our ability to pay dividends is subject to certain restrictions, as described in Note 22 - "Dividend Restrictions and Statutory Financial Information" .

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Earnings Per Share	18. EARNINGS PER SHARE The following table sets forth the computation of basic and diluted earnings per share for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Numerator: Net earnings (loss) from continuing operations $ 902,175 $ (162,354 ) $ 300,465 Net earnings from discontinued operations, net of income taxes — — 10,993 Net earnings (loss) attributable to Enstar Group Limited $ 902,175 $ (162,354 ) $ 311,458 Denominator: Weighted-average ordinary shares outstanding — basic 21,482,617 20,698,310 19,388,621 Effect of dilutive securities: Share-based compensation plans 227,878 129,746 62,732 Warrants 64,571 76,120 76,238 Weighted-average ordinary shares outstanding — diluted 21,775,066 20,904,176 19,527,591 Earnings per share attributable to Enstar Group Limited: Basic: Net earnings (loss) from continuing operations $ 42.00 $ (7.84 ) $ 15.50 Net earnings from discontinued operations, net of income taxes — — 0.56 Net earnings (loss) per ordinary share $ 42.00 $ (7.84 ) $ 16.06 Diluted (1) : Net earnings (loss) from continuing operations $ 41.43 $ (7.84 ) $ 15.39 Net earnings from discontinued operations, net of income taxes — — 0.56 Net earnings (loss) per ordinary share $ 41.43 $ (7.84 ) $ 15.95 (1) During a period of loss, the basic weighted average ordinary shares outstanding is used in the denominator of the diluted loss per ordinary share computation as the effect of including potentially dilutive securities would be anti-dilutive.

Share-Based Compensation and Pe

Share-Based Compensation and Pensions	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Share-Based Compensation and Pensions	19. SHARE-BASED COMPENSATION AND PENSIONS Share-based compensation The 2016 and 2006 Equity Incentive Plans are our primary share-based compensation plans. We also maintain other share-based compensation plans as discussed below. The table below provides a summary of the compensation costs for all of our share-based compensation plans for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Share-based compensation plans: Restricted shares and restricted share units $ 6,564 $ 7,641 $ 7,302 Performance share units 23,582 1,968 5,832 Cash-settled stock appreciation rights 2,575 (3,316 ) 8,875 Other share-based compensation plans: Northshore incentive plan 3,652 2,792 3,156 StarStone incentive plan 223 — — Deferred compensation and ordinary share plan for non-employee directors 992 1,155 758 Employee share purchase plan 411 430 403 Total share-based compensation $ 37,999 $ 10,670 $ 26,326 Restricted Shares and Restricted Share Units Restricted shares and restricted share units are service awards that typically vest over three years. These awards are share-settled and are recorded in additional paid-in capital on the consolidated balance sheets. The fair value of these awards is measured at the grant date and expensed over the service period. The following ta ble summarizes the activity related to restricted shares and restricted share awards during 2019 : Number of Shares Weighted-Average Share Price Nonvested — January 1 59,936 $191.89 Granted 50,054 176.16 Vested (42,462 ) 189.98 Forfeited (2,956 ) 206.85 Nonvested — December 31 64,572 180.49 The unrecognized compensation cost related to our unvested restricted share and restricted share unit awards as of December 31, 2019 was $6.0 million . This cost is recognizable over the next 2.10 Performance Share Units ("PSUs") PSUs are share-settled and vest on the third anniversary of the grant date. The number of shares to vest will be determined by a performance adjustment based on either (i) the change in fully diluted book value per share ("FDBVPS") over three years, or (ii) average annual non-GAAP operating income return on equity, excluding StarStone. Performance Share Units based on FDBVPS The following table summarizes the awards granted, the unvested PSU awards at December 31, 2019 , and the performance criteria and associated performance multipliers at various levels of achievement. Grant Year Inception-to-date Activity Roll-forward Performance Criteria: Change in FDBVPS (3 year) Performance Multiplier Levels Per Award Agreements PSUs Granted at Target Forfeited Estimated Change in Multiplier Nonvested at December 31, 2019 Threshold Target Maximum Threshold Target Maximum 2017 36,321 (12,176 ) 9,560 33,705 20.00 % 30.00 % 40.00 % 50.00 % 100.00 % 150.00 % 2017 91,875 — 18,081 109,956 30.30 % 35.65 % 41.00 % 50.00 % 100.00 % 150.00 % 2018 39,682 (11,414 ) — 28,268 25.00 % 32.50 % 40.00 % 50.00 % 100.00 % 150.00 % 2019 18,308 (798 ) — 17,510 20.00 % 30.00 % 40.00 % 60.00 % 100.00 % 150.00 % 186,186 (24,388 ) 27,641 189,439 An increase of Target to Maximum or more in FDBVPS results in a settlement of 100% to a maximum of 150% of the units granted, respectively. An increase of Threshold to Target in FDBVPS results in a settlement of 50% to 100% of the units granted, respectively for 2017 and 2018 awards, and settlement of 60% to 100% for the 2019 awards. Straight-line interpolation applies within these ranges, and no settlement occurs if the increase in FDBVPS is less than the Threshold. Performance Share Units based on Average Annual Non-GAAP Operating Income Return on Equity ("Operating ROE") The following table summarizes the awards granted, the unvested units at December 31, 2019 , and the performance criteria and associated performance multipliers at various levels of achievement. Grant Year Inception-to-date Activity Roll-forward Performance Criteria: Average Annual Operating ROE Performance Multiplier Levels Per Award Agreements PSUs Granted at Target Forfeited Estimated Change in Multiplier Nonvested at December 31, 2019 Threshold Target Maximum Threshold Target Maximum 2019 18,308 (798 ) — 17,510 9.60 % 12.00 % 14.40 % 60.00 % 100.00 % 150.00 % Annual Operating ROE is calculated based upon the non-GAAP operating income return on opening shareholder's equity, excluding StarStone. Average Annual Operating ROE is the sum of the three individual year annual operating ROE %'s divided by three. An Average Annual Operating ROE of Target to Maximum or more results in a settlement of 100% to a maximum of 150% of the units granted, respectively. An Average Annual Operating ROE of Threshold to Target results in a settlement of 60% to 100% . Straight-line interpolation applies within these ranges and no settlement occurs if the Average Annual Operating ROE is less than the Threshold. Performance Multipliers For expense purposes we assume a Target vesting at the initial time of award. At the end of each reporting period, we estimate the expected performance multiplier, as shown in the table below: Award Description 2019 2018 2017 2017 FDBVPS Type I (30.00% Target Change) 139% 50% 100% 2017 FDBVPS Type II (35.65% Target Change) 120% 50% 100% 2018 FDBVPS 100% 50% n/a 2019 FDBVPS 100% n/a n/a 2019 Average Operating ROE 100% n/a n/a The unrecognized compensation cost related to our unvested PSU share awards as of December 31, 2019 was $7.9 million . This cost is recognizable over the next 1.51 years, which is the weighted average contractual life. Roll-forward of Performance Share Units The following table summarizes the activity related to PSUs during 2019 : Number of Shares Weighted-Average Share Price Nonvested — January 1 159,168 $190.77 Granted 36,616 166.42 Increase for above target vest 27,641 188.62 Vested (2,631 ) 195.60 Forfeited (13,845 ) 198.37 Nonvested — December 31 206,949 185.61 Cash-Settled Stock Appreciation Rights Cash-settled stock appreciation right awards ("SARs") give the holder the right, upon exercise, to receive in cash the difference between the market price per share of our ordinary shares at the time of exercise and the exercise price of the SARs. The exercise price of each SAR is equal to the market price of our ordinary shares on the date of the grant. Vested SARs are exercisable for periods not to exceed either 4 years or 10 years from the date of grant. We have not granted any new SAR awards since 2015. The following t able summarizes the activity related to SARs during 2019 : Number of SARs Weighted-Average Exercise Price of SARs Weighted-Average Expected Term (in years) Aggregate Intrinsic Value (1) Balance, beginning of year 109,081 $ 142.37 Exercised (19,854 ) 138.07 Balance, end of year 89,227 143.33 2.39 $ 6,133 (1) The aggregate intrinsic value is calculated as the pre-tax difference between the exercise price of the underlying share awards and the closing price per share of our ordinary shares of $206.86 on December 31, 2019 . Compensation expense for SARs is based on the estimated fair value on the date of grant using the Black-Scholes valuation model, which requires the use of subjective assumptions related to the expected stock price volatility, expected term, expected dividend yield and risk-free interest rate. SARs are liability-classified awards for which compensation expense and the liability are re-measured using the then-current Black Scholes assumptions at each interim reporting date based upon the portion of the requisite service period rendered. The unrecognized compensation cost related to our SARs as of December 31, 2019 was less than $0.1 million . The following table sets forth the assumptions used to estimate the fair value of the SARs using the Black-Scholes option valuation model as of December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Weighted-average fair value per SAR $ 76.03 $ 45.85 $ 75.38 Weighted-average volatility 19.75 % 18.94 % 19.44 % Weighted-average risk-free interest rate 1.64 % 2.72 % 1.65 % Dividend yield 0.00 % 0.00 % 0.00 % Joint Share Ownership Plan Under the JSOP, we have the ability to make equity awards to our U.K.-based staff through which a recipient acquires jointly held interests in a set number of our Voting Ordinary Shares together with the independent trustee of the EB Trust at fair market value, pursuant to the terms of a joint ownership agreement . The Voting Ordinary Shares underlying any JSOP award remain in the EB Trust, and the recipient ultimately receives the value of the appreciation above a threshold on those shares, measured between date of grant and a pre-set measuring date that follows a vesting period (typically three years). JSOP awards are generally settled in Voting Ordinary Shares and may include performance and other conditions, typically related to share price appreciation above a hurdle, that must be met in order for the award to vest. Voting rights in respect of shares held in the EB Trust are contractually waived. Shares held in the EB Trust are classified as treasury shares. No awards under the JSOP were made during 2019 . Subsequent to December 31, 2019, a JSOP award comprising 565,630 underlying Voting Ordinary Shares was made to our Chief Executive Officer (the "CEO JSOP Award"). The CEO JSOP Award was granted on January 21, 2020 and cliff-vests after 3 years . The ultimate value of the CEO JSOP Award at vesting, if any, is determined based on the price of a Voting Ordinary Share appreciating above a certain threshold between the date of grant and the vesting date. If the higher of the closing price per Share on January 20, 2023 and the 10-day volume weighted average price per Share for the ten consecutive trading days ending on January 20, 2023 (each, the "Market Price") is $266.00 or greater (the "Hurdle"), the award will have a value equal to the applicable Market Price per Share, less $205.89 , multiplied by 565,630 . If the higher of the Market Price per Voting Ordinary Share is less than $266.00 Other share-based compensation plans Northshore Incentive Plan Our subsidiary, Northshore, has long-term incentive plans that award time-based restricted shares of Northshore to certain Atrium employees. Shares generally vest over two to three years. These share awards have been classified as liability awards. The unrecognized compensation cost related to the Northshore incentive plan at December 31, 2019 was $0.9 million . This cost is expected to be recognized over the next 0.36 StarStone Incentive Plan Our subsidiary, StarStone, has long-term incentive plans that are cash-settled plans for StarStone employees. The awards are based on StarStone's performance over two to three years. These share awards have been classified as liability awards. The unrecognized compensation cost related to the StarStone incentive plan at December 31, 2019 was $1.8 million . This cost is expected to be recognized over the next 2 Deferred Compensation and Ordinary Share Plan for Non-Employee Directors The following table summarizes the number of units outstanding for the years ended December 31, 2019 , 2018 and 2017 under the Enstar Group Limited Deferred Compensation and Ordinary Share Plan for Non-Employee Directors (the "Deferred Compensation Plan"): 2019 2018 2017 Restricted share units credited to the accounts of non-employee directors 5,976 5,691 3,852 Employee Share Purchase Plan We provide an Employee Share Purchase Plan whereby eligible employees may purchase Enstar shares at a 15% discount to market price, in an amount of share value limited to the lower of $21,250 or 15% of the employee's base salary. The 15% discount is expensed as compensation cost. The following table summarizes the number of shares issued to employees under the Employee Share Purchase Plan for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Number of shares issued to employees 15,269 14,183 12,401 Pension Plans We provide retirement benefits to eligible employees through various plans that we sponsor. Pension expense can be affected by changes in our employee headcount. The table below summarizes the pension expenses related to our Defined Contribution Plans and our Defined Benefit Plan for the years ended December 31, 2019 , 2018 and 2017 . 2019 2018 2017 Defined contribution plans $ 11,798 $ 11,434 $ 12,247 Defined benefit plan 684 2,243 1,988 Total pension expense $ 12,482 $ 13,677 $ 14,235 Defined Benefit Plan During 2019 , an actuarial review was performed on the defined benefit plan, which determined that the plan’s unfunded liability, as of December 31, 2019 and 2018 was $8.9 million and $8.4 million , respectively. As of December 31, 2019 and 2018 , we had an accrued liability of $8.9 million and $8.4 million , respectively, for this p

Income Taxation

Income Taxation	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxation	20. INCOME TAXATION Enstar Group Limited is incorporated under the laws of Bermuda and under Bermuda law is not required to pay taxes in Bermuda based upon income or capital gains. The Company, under the Exempted Undertakings Tax Protection Act of 1966, is protected against any legislation that may be enacted in Bermuda which would impose any tax on profits, income, or gain until March 31, 2035. We have foreign operating subsidiaries and branch operations principally located in the United States, United Kingdom, Continental Europe and Australia that are subject to federal, foreign, state and local taxes in those jurisdictions. Deferred tax liabilities have not been accrued with respect to the undistributed earnings of our foreign subsidiaries. If the earnings were to be distributed, as dividends or other distributions, withholding taxes may be imposed by the jurisdiction of the paying subsidiary. For our U.S. subsidiaries, we have not currently accrued any withholding taxes with respect to unremitted earnings as management has indefinitely reinvested these earnings. For our United Kingdom subsidiaries, there are no withholding taxes imposed. For our other foreign subsidiaries, it would not be practicable to compute such amounts due to a variety of factors, including the amount, timing, and manner of any repatriation. Because we operate in many jurisdictions, our net earnings are subject to risk due to changing tax laws and tax rates around the world. The current, rapidly changing economic environment may increase the likelihood of substantial changes to tax laws in the jurisdictions in which we operate. The following table presents earnings (loss) before income taxes by jurisdiction from continuing operations, including earnings (loss) from equity method investments, for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Domestic (Bermuda) $ 576,339 $ (232,743 ) $ 167,263 Foreign 356,317 14,347 147,148 Total earnings (loss) before income tax on continuing operations $ 932,656 $ (218,396 ) $ 314,411 The following table presents our current and deferred income tax expense (benefit) from continuing operations by jurisdiction for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Current: Domestic (Bermuda) $ — $ — $ — Foreign 18,433 (3,632 ) 10,299 18,433 (3,632 ) 10,299 Deferred: Domestic (Bermuda) — — — Foreign (13,996 ) (2,492 ) (16,694 ) (13,996 ) (2,492 ) (16,694 ) Total income tax expense (benefit) on continuing operations $ 4,437 $ (6,124 ) $ (6,395 ) The actual effective income tax rate differs from the statutory rate of 0% under Bermuda law to earnings (loss) from continuing operations before income taxes, including earnings (loss) from equity method investments for the years ended December 31, 2019 , 2018 and 2017 as shown in the following reconciliation: 2019 2018 2017 Earnings (loss) before income tax $ 932,656 $ (218,396 ) $ 314,411 Bermuda income taxes at statutory rate 0.0 % 0.0 % 0.0 % Foreign income tax rate differential 8.6 % 0.7 % 13.1 % Change in valuation allowance (8.2 )% (0.3 )% (34.9 )% Effect of change in foreign (U.S.) tax rate — % — % 20.3 % U.S. base erosion and anti-abuse tax 0.5 % (0.6 )% — % Other (0.4 )% 3.0 % (0.5 )% Effective tax rate 0.5 % 2.8 % (2.0 )% Our effective tax rate is generally driven by the geographical distribution of our pre-tax net earnings between our taxable and non-taxable jurisdictions. Deferred Tax Assets and Liabilities Deferred tax assets and liabilities reflect the tax effect of the differences between the financial statement carrying amount and the income tax bases of assets and liabilities. Significant components of the deferred tax assets and deferred tax liabilities as of December 31, 2019 and 2018 were as follows: 2019 2018 Deferred tax assets: Net operating loss carryforwards $ 159,436 $ 183,633 Insurance reserves 14,104 18,677 Unearned premiums 7,131 11,314 Lloyd's underwriting losses taxable in future periods — 6,201 Provisions for bad debt 6,172 2,594 Unrealized losses on investments — 5,160 Defendant asbestos and environmental liabilities (1) 140,000 — Other deferred tax assets — 183 Gross deferred tax assets 326,843 227,762 Valuation allowance (117,390 ) (212,113 ) Deferred tax assets 209,453 15,649 Deferred tax liabilities: Unrealized gains on investments (10,107 ) — Lloyd's underwriting profit taxable in future periods (8,852 ) — Deferred policy acquisition cost (8,267 ) — Other deferred tax liabilities (27,317 ) (16,067 ) Deferred tax liabilities (54,543 ) (16,067 ) Net deferred tax asset (liability) $ 154,910 $ (418 ) (1) Relates to the Morse TEC acquisition as described in Note 3 - "Acquisitions" . Net Deferred Tax Asset (Liability) Balance by Major Jurisdiction: December 31, 2019 2018 Net Deferred Tax Asset Net Deferred Tax Liability United States $ 169,891 $ 5,151 United Kingdom (16,074 ) (8,377 ) Other 1,093 2,808 Total $ 154,910 $ (418 ) Net Operating Loss Carryforwards: As of December 31, 2019 , we had net operating loss carryforwards that could be available to offset future taxable income, as follows: Tax Jurisdiction Loss Carryforwards Tax effect Expiration Operating and Capital Loss Carryforwards: United States - Net operating loss $ 513,476 $ 107,830 2024-2038 United Kingdom 224,150 38,106 Indefinitely Other 52,484 13,500 Various The U.S. net operating loss carryforwards are also subject to certain utilization limitations based upon their nature and the specific legal entity that holds them. Assessment of Valuation Allowance on Deferred Tax Assets As of December 31, 2019 and 2018 , we had deferred tax asset valuation allowances of $117.4 million and $212.1 million , respectively, related to foreign subsidiaries. We recorded a decrease of $94.7 million in our deferred tax valuation allowance primarily due to utilization of deferred tax asset in the amount of $69.7 million as well as a partial deferred tax asset valuation allowance release in the amount of $25.0 million during 2019 . The realization of deferred tax assets is dependent on generating sufficient taxable income in future periods in which the tax benefits are deductible or creditable. The amount of the deferred tax asset considered realizable, however, could be revised in the future if estimates of future taxable income change. Taxes are determined and assessed jurisdictionally by legal entity or by filing group. Certain jurisdictions require or allow combined or consolidated tax filings. We have estimated future taxable income of our foreign subsidiaries and provided a valuation allowance in respect of those assets where we do not expect to realize a benefit. We have considered all available evidence using a “more likely than not” standard in determining the amount of the valuation allowance. We considered the following evidence: (i) net earnings or losses in recent years; (ii) the future sustainability and likelihood of positive net earnings of our subsidiaries; (iii) the carryforward periods of tax losses including the effect of reversing temporary differences; and (iv) tax planning strategies, in making our determination. The assumptions used in determining future taxable income require significant judgment and any changes in these assumptions could have an impact on earnings . During the years ended December 31, 2019 , 2018 and 2017 , there were no unrecognized tax benefits. There were no accruals for the payment of interest and penalties related to unrecognized tax benefits as of December 31, 2019 , 2018 and 2017 . Our operating subsidiaries may be subject to audit by various tax authorities and may have different statutes of limitations expiration dates. Tax authorities may propose adjustments to our income taxes. Listed below are the tax years that remain subject to examination by a major tax jurisdiction as of December 31, 2019 : Major Tax Jurisdiction Open Tax Years United States 2016-2019 United Kingdom 2016-2019 Australia 2014-2019 Impact of U.S. Tax Reform On December 22, 2017, the U.S. Government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act ("Tax Act"). The Tax Act resulted in a reduction of the U.S. Federal Tax rate to 21% from 35% effective for tax years beginning after December 31, 2017. Consequently, we recorded a $63.8 million reduction of our U.S. deferred tax asset fully offset by a reduction in our valuation allowance in 2017. The Tax Act also repealed the corporate AMT. Taxpayers with AMT credit carryovers in excess of their tax liability may have the credits refunded over multiple years between 2018 and 2021. For the year ended December 31, 2017, we had recorded a reduction to our valuation allowance of $7.4 million and reclassified our AMT credit carryforward to other assets on our consolidated balance sheet. The AMT carryforward has been refunded 50% each tax year beginning in 2018 with any remaining balance expected to be fully refunded in 2021. Australia The Company’s Australian insurance subsidiary is regulated and subject to prudential supervision by the Australian Prudential Regulation Authority (“APRA”). APRA is the primary regulatory body responsible for regulating compliance with the Insurance Act 1973. APRA’s prudential standards require that all insurers maintain and meet prescribed capital adequacy requirements to enable their insurance obligations to be met under a wide range of circumstances.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	21. RELATED PARTY TRANSACTIONS Stone Point Capital LLC Through several private transactions occurring from May 2012 to July 2012 and an additional private transaction that closed in May 2018, investment funds managed by Stone Point Capital LLC ("Stone Point") have acquired an aggregate of 1,635,986 of our Voting Ordinary Shares (which constitutes approximately 9.1% of our outstanding Voting Ordinary Shares). On November 6, 2013, we appointed James D. Carey to our Board of Directors. Mr. Carey is the sole member of an entity that is one of four general partners of the entities serving as general partners for Trident, is a member of the investment committees of such general partners, and is a member and senior principal of Stone Point, the manager of the Trident funds. In addition, we have entered into certain agreements with Trident with respect to Trident’s co-investments in the Atrium, Arden, and StarStone acquisitions. These include investors’ agreements and shareholders’ agreements, which provide for, among other things: (i) our right to redeem Trident’s equity interest in the Atrium/Arden and StarStone transactions in cash at fair market value within the 90 days following September 6, 2018 and April 1, 2019, respectively, and at any time following September 6, 2020 and April 1, 2021, respectively; and (ii) Trident’s right to have its equity co-investment interests in the Atrium/Arden and StarStone transactions redeemed by us at fair market value (which we may satisfy in either cash or our ordinary shares) following September 6, 2020 and April 1, 2021, respectively. We did not exercise our right to redeem Trident's equity interest in Atrium/Arden during the 90 days following September 6, 2018, nor did we exercise our right to redeem Trident's equity interest in StarStone during the 90 days following April 1, 2019. Pursuant to the terms of the shareholders’ agreements, Mr. Carey serves as a Trident representative on the boards of the holding companies, including North Bay Holdings Limited ("North Bay"), established in connection with the Atrium/Arden and StarStone co-investment transactions. Trident also has a second representative on these boards who is a Stone Point employee. We, in partnership with StarStone's other shareholders, have recently completed transactions to provide capital support to StarStone in the form of: (i) a contribution to its contributed surplus account and a loss portfolio transfer, effective October 1, 2018. To fund the transaction, the North Bay shareholders contributed an aggregate amount of $135.0 million to North Bay in proportion to their ownership interests. Trident’s proportionate contribution of $53.1 million was temporarily funded by North Bay and was reimbursed in the first quarter of 2019; and (ii) a loss portfolio transfer, effective April 1, 2019, for which shareholders agreed to contribute an aggregate amount of $48.0 million . In addition, Enstar has separately entered into a loss portfolio transfer and adverse development cover with StarStone effective October 1, 2019, whereby StarStone transferred $189.4 million in loss reserves and unearned premium to a wholly-owned Enstar subsidiary in exchange for premium of $189.4 million . Enstar also provided an additional $59.0 million adverse development cover in excess of the $189.4 million . As of December 31, 2019 and December 31, 2018 , the RNCI on our balance sheet relating to these Trident co-investment transactions was as follows: 2019 2018 Redeemable Noncontrolling Interest $ 420,499 $ 439,428 As of December 31, 2019 , we had the following additional relationships with Stone Point and its affiliates: • Investments in funds (carried within other investments) managed by Stone Point, with respect to which we recognized net unrealized gains (losses); • Investments in registered investment companies affiliated with entities owned by Trident or otherwise affiliated with Stone Point, with respect to which we recognized net unrealized gains (losses) and interest income; • Separate accounts managed by Eagle Point Credit Management, PRIMA Capital Advisors and SKY Harbor Capital Management, which are affiliates of entities owned by Trident, with respect to which we incurred management fees; • Investments in funds (carried within other investments) managed by Sound Point Capital, an entity in which Mr. Carey has an indirect minority ownership interest and serves as a director, with respect to which we recognized net unrealized gains (losses); • Sound Point Capital has acted as collateral manager for certain of our direct investments in CLO debt and equity securities, with respect to which we recognized net unrealized gains (losses) and interest income; • Marble Point Capital, which is an affiliate of an entity owned by Trident, has acted as collateral manager for certain of our direct investments in CLO debt and equity securities, with respect to which we recognized net unrealized gains (losses) and interest income; • A separate account managed by Sound Point Capital, with respect to which we incurred management fees in prior periods; and • In the fourth quarter of 2018, we invested $25.0 million in Mitchell TopCo Holdings, the parent company of Mitchell International and Genex Services, as a co-investor alongside certain Trident funds. The following table presents the amounts included in our consolidated balance sheet related to our related party transactions with Stone Point and its affiliated entities: December 31, 2019 December 31, 2018 Short-term investments, available-for-sale, at fair value $ 1,431 $ — Fixed maturities, trading, at fair value 269,131 176,193 Fixed maturities, available-for-sale, at fair value 160,303 — Equities, at fair value 121,794 57,319 Other investments, at fair value: Hedge funds 18,993 19,535 Fixed income funds 381,449 324,561 Private equity funds 34,858 52,925 CLO equities 32,560 15,372 CLO equity funds 87,509 37,260 Private Debt 16,312 10,387 Real estate fund 18,106 8,025 Cash and cash equivalents 54,080 11,739 Other assets 10 5,216 Other liabilities 4,710 4,240 The following table presents the amounts included in net earnings related to our related party transactions with Stone Point and its affiliated entities: 2019 2018 2017 Net investment income $ 8,733 $ 7,424 $ 5,990 Net realized and unrealized gains (losses) 26,631 207 24,684 Total net earnings $ 35,364 $ 7,631 $ 30,674 On December 15, 2016, KaylaRe completed an initial capital raise of $620.0 million . We originally owned approximately 48.2% of KaylaRe's common shares and recorded our investment in KaylaRe using the equity method basis of accounting, pursuant to the conclusion that we were not required to consolidate following an analysis based on the guidance in ASC 810 - Consolidation . On May 14, 2018 , we completed a transaction to acquire all of the outstanding shares and warrants of KaylaRe, following the receipt of all required regulatory approvals. In consideration for the acquired shares and warrants of KaylaRe, we issued an aggregate of 2,007,017 ordinary shares, comprising 1,501,778 voting ordinary shares and 505,239 Series E non-voting ordinary shares to the shareholders of KaylaRe as follows: (i) 1,204,353 voting ordinary shares and 505,239 Series E Shares to a fund managed by Hillhouse Capital Management, Ltd.; (ii) 285,986 voting ordinary shares to Trident; and (iii) 11,439 voting ordinary shares to the minority shareholder . In addition, the Shareholders Agreement between Enstar and the other KaylaRe shareholders was effectively terminated. Effective May 14, 2018 we consolidated KaylaRe into our consolidated financial statements and any balances between KaylaRe and Enstar are now eliminated upon consolidation. Refer to Note 3 - "Acquisitions" for additional information. Effective September 30, 2019, KaylaRe and KaylaRe Ltd. merged with Cavello Bay Reinsurance Limited, a wholly owned subsidiary of the Company, with Cavello Bay Reinsurance Limited as the surviving company. Through a Quota Share Agreement dated December 15, 2016 (the "KaylaRe-StarStone QS"), several of our StarStone affiliates entered into a Quota Share Treaty with KaylaRe Ltd. pursuant to which KaylaRe Ltd. reinsured 35% of all business written by these StarStone affiliates for risks attaching from January 1, 2016, net of the StarStone affiliates’ external reinsurance programs. The reinsurance of StarStone's U.S. affiliates was non-renewed as of January 1, 2018, and the reinsurance of its U.K. and European affiliates was non-renewed as of January 1, 2019. In addition, Fitzwilliam Insurance Limited ("Fitzwilliam"), one of our non-life run-off subsidiaries, ceded $177.2 million of loss reserves to KaylaRe Ltd. in 2016, on a funds held basis. Under the terms of this reinsurance agreement, Fitzwilliam is entitled to receive a profit commission calculated with reference to reserve savings made during the term of this agreement. Our Non-life Run-off subsidiaries did not cede any new business to KaylaRe Ltd. during years ended December 31, 2019 and 2018 . Our consolidated statement of earnings for the years ended December 31, 2018 and 2017 included the following balances related to transactions between us and KaylaRe and KaylaRe Ltd. up until May 14, 2018, the date of acquisition: 2018 2017 Fee income due to Enstar Limited $ 1,453 $ 2,679 Transactions under KaylaRe-StarStone QS: Ceded premium earned (52,651 ) (234,079 ) Net incurred losses 31,654 155,433 Acquisition costs 18,774 99,500 Transactions under Fitzwilliam reinsurance agreement: Profit Commission — 18,843 Total net earnings (loss) $ (770 ) $ 42,376 Investment funds managed by Hillhouse Capital Advisors, Ltd. ("Hillhouse Capital") collectively own approximately 9.7% of Enstar’s voting ordinary shares. These funds also own non-voting ordinary shares and warrants to purchase additional non-voting ordinary shares, which together with their voting ordinary shares, represent an approximate 17.0% economic interest in Enstar. In February 2017, Jie Liu, a Partner of Hillhouse Capital, was appointed to our Board. We have direct investments in funds managed by Hillhouse Capital and its affiliate, AnglePoint Asset Management Ltd. ("AnglePoint"), (together with such parties' affiliates, "Hillhouse"). As of December 31, 2019 , the carrying value of our direct investment in the InRe Fund, L.P. (the "InRe Fund"), which is managed by AnglePoint, was $918.6 million with the fund's assets being invested in approximately 18% in fixed income securities, 6% in North American equities, 96% in international equities and (20)% in financing, derivatives and other items. As of December 31, 2019 and December 31, 2018 , our equity method investee, Enhanzed Re, had investments in a fund managed by AnglePoint, as set forth in the table below. Our consolidated balance sheet as of December 31, 2019 and 2018 included the following balances related to transactions with Hillhouse: 2019 2018 Investments in funds managed by AnglePoint, held by Enhanzed Re $ 327,799 $ 75,192 Our ownership of equity method investments 47.4 % 47.4 % Our share of Enhanzed Re's funds managed by AnglePoint $ 155,377 $ 35,641 Investment in other funds managed by Hillhouse: InRe Fund $ 918,633 $ 678,420 Other funds 232,968 166,646 $ 1,151,601 $ 845,066 On January 1, 2020 Enhanzed Re invested an additional $54.0 million into funds managed by Hillhouse. The increase in the investment in funds managed by Hillhouse was primarily due to unrealized gains for the year ended December 31, 2019 . We incurred fees of approximately $89.0 million , included within the funds' reported NAV, for the year ended December 31, 2019 in relation to the direct investment in funds managed by Hillhouse as described above. Monument Monument Insurance Group Limited ("Monument") was established in October 2016 and Enstar has invested a total of $26.6 million in the common and preferred shares of Monument. We have approximately a 26.6% interest in Monument. I n connection with our investment in Monument, we entered into a Shareholders Agreement with the other shareholders. We recorded the investment in Monument using the equity method basis of accounting, as we concluded that we are not required to consolidate based on the guidance in ASC 810 - Consolidation . On August 29, 2017, we sold our wholly-owned subsidiary, Laguna, to a subsidiary of Monument for a total consideration of €25.6 million (approximately $30.8 million ). The total loss recorded on the sale of Laguna, for the year ended December 31, 2017 was $16.3 million , which has been included in earnings from continuing operations before taxes in our consolidated statement of earnings. This loss includes a cumulative currency translation adjustment balance of $6.3 million , which has been reclassified from accumulated other comprehensive income and included in earnings as a component of the loss on sale of Laguna during the year ended December 31, 2017, following the closing of the sale. On May 31, 2019, we completed the transfer of our remaining life assurance policies written by our wholly-owned subsidiary Alpha Insurance SA to a subsidiary of Monument. In this transaction, we transferred policy benefits for life and annuity contracts with a carrying value of €88.8 million (or approximately $99.1 million ) and total assets with a fair value of €91.1 million (or approximately $101.6 million ) to a subsidiary of Monument. Our investment in the common and preferred shares of Monument, carried in equity method investments on our consolidated balance sheet, as of December 31, 2019 and 2018 was as follows: 2019 2018 Investment in Monument $ 60,598 $ 42,193 Clear Spring (formerly SeaBright) Effective January 1, 2017, we sold SeaBright Insurance Company (“SeaBright Insurance”) and its licenses to Delaware Life Insurance Company ("Delaware Life"), a subsidiary of Guggenheim Partners, LLC. Following the sale, SeaBright Insurance was renamed Clear Spring Property and Casualty Company (“Clear Spring”). Clear Spring was subsequently capitalized with $56.0 million of equity, with Enstar retaining a 20% indirect equity interest in Clear Spring. We have accounted for our equity interest in Clear Spring as an equity method investment as we have significant influence over its operating and financial policies. We have recorded the investment in Clear Spring using the equity method basis of accounting, pursuant to the conclusion that we are not required to consolidate following an analysis based on the guidance in ASC 810 - Consolidation . Our investment in the common shares of Clear Spring, carried in equity method investments on our consolidated balance sheet, as of December 31, 2019 and 2018 was as follows: 2019 2018 Investment in Clear Spring $ 10,645 $ 10,070 Effective January 1, 2017, StarStone National Insurance Company (“StarStone National”) entered into a ceding quota share treaty with Clear Spring pursuant to which Clear Spring reinsures 33.3% of core workers' compensation business written by StarStone National. This agreement was terminated as of December 31, 2018. Effective January 1, 2017, we also entered into an assuming quota share treaty with Clear Spring pursuant to which an Enstar subsidiary reinsures 25% of all workers' compensation business written by Clear Spring. This is recorded as other activities. Our consolidated balance sheet as of December 31, 2019 and 2018 included the following balances between us and Clear Spring: 2019 2018 Balances under StarStone ceding quota share: Reinsurance balances recoverable on paid and unpaid losses $ 22,812 $ 23,718 Prepaid insurance premiums 51 13,821 Ceded payable 3,616 14,153 Ceded acquisition costs 21 3,233 Balances under assuming quota share: Losses and LAE 6,135 5,778 Unearned reinsurance premiums 13 3,455 Funds held 8,611 10,242 Our consolidated statement of earnings for the years ended December 31, 2019 and 2018 included the following amounts between us and Clear Spring: 2019 2018 2017 Amounts under StarStone ceding quota share: Ceded premium earned $ (14,994 ) $ (29,520 ) (14,256 ) Net incurred losses and LAE 6,567 18,143 9,533 Acquisition costs 356 7,035 6,718 Amounts under assuming quota share: Premium earned 3,749 7,380 3,564 Net incurred losses and LAE (2,202 ) (4,536 ) (1,181 ) Acquisition costs (92 ) (1,836 ) (1,753 ) Total net earnings (loss) $ (6,616 ) $ (3,334 ) $ 2,625 AmTrust In November 2018, pursuant to a Subscription Agreement with Evergreen Parent L.P. ("Evergreen"), K-Z Evergreen, LLC and Trident Pine Acquisition LP ("Trident Pine"), we purchased equity in Evergreen in the aggregate amount of $200.0 million . Evergreen is an entity formed by private equity funds managed by Stone Point and the Karfunkel-Zyskind family that acquired the approximately 45% of the issued and outstanding shares of common stock of AmTrust that the Karfunkel-Zyskind Family and certain of its affiliates and related parties did not already own or control. The equity interest was in the form of three separate classes of equity securities issued at the same price and in the same proportion as the equity interest purchased by Trident Pine. In a second transaction in December 2019, Enstar acquired an additional $25.9 million of Evergreen securities from another investor. Following the closing of the second transaction, Enstar owns approximately 8.5% of the equity interest in Evergreen and Trident Pine owns approximately 21.8% . Evergreen owns all of the equity interest in AmTrust. In addition, upon the successful closing of the transaction we received a fee of $3.3 million Our indirect investment in the shares of AmTrust, carried in equities on our consolidated balance sheet, as of December 31, 2019 was as follows: 2019 2018 Investment in AmTrust $ 240,115 $ 200,000 During the years ended December 31, 2019 and 2018 we recorded net investment income of $7.7 million and $0.3 million , respectively, and net realized and unrealized gains of $10.1 million and $nil , respectively, related to our indirect equity investment in AmTrust. Citco In June 2018, we made a $50.0 million indirect investment in the shares of Citco III Limited ("Citco"), a fund administrator with global operations. Pursuant to an investment agreement and in consideration for participation therein, a related party of Hillhouse provided us with investment support. In a private transaction that preceded our co-investment opportunity, certain Citco shareholders, including Trident, agreed to sell all or a portion of their interests in Citco. As of December 31, 2019 , Trident owned an approximate 3.4% interest in Citco. Mr. Carey currently serves as an observer to the board of directors of Citco in connection with Trident's investment therein. Our indirect investment in the shares of Citco, carried in equity method investments on our consolidated balance sheet, as of December 31, 2019 and 2018 was as follows: 2019 2018 Investment in Citco $ 51,742 $ 50,812 Enhanzed Re Enhanzed Reinsurance Ltd. ("Enhanzed Re") is a joint venture between Enstar, Allianz SE and Hillhouse that was capitalized in December 2018. Enhanzed Re is a Bermuda-based Class 4 and Class E reinsurer of life, non-life run-off, and property and casualty insurance business, initially sourced from Allianz SE and Enstar. E nstar, Allianz and Hillhouse affiliates have made equity investment commitments in aggregate of $470.0 million to Enhanzed Re. Enstar owns 47.4% of the entity, Allianz owns 24.9% , and an affiliate of Hillhouse owns 27.7% . As of December 31, 2019 , Enstar contributed $154.1 million of its total capital commitment to Enhanzed Re and had an uncalled amount of $68.7 million . We have accounted for our equity interest in Enhanzed Re as an equity method investment as we have significant influence over its operating and financial policies. Enstar acts as the (re)insurance manager for Enhanzed Re, for which it receives fee income recorded within other income, Hillhouse acts as primary investment manager, and an affiliate of Allianz SE provides investment management services. Enhanzed Re intends to write business from affiliates of its operating sponsors, Allianz SE and Enstar. It will seek to underwrite business to maximize diversification by risk and geography. Our investment in the common shares of Enhanzed Re, carried in equity method investments on our consolidated balance sheet, as of December 31, 2019 was as follows: 2019 2018 Investment in Enhanzed Re $ 182,856 $ 94,800 We have ceded 10% of the Zurich transaction, as discussed in Note 4 - "Significant New Business" Our consolidated balance sheet as of December 31, 2019 and 2018 included the following balances between us and Enhanzed Re: 2019 Balances under ceding quota share: Insurance balances payables $ 1,443 Reinsurance balances recoverable 59,601 Funds held 50,089 Other assets 1,033 Our consolidated statement of earnings for the years ended December 31, 2019 and 2018 included the following amounts between us and Enhanzed Re: 2019 Amounts under ceding quota share: Acquisition costs $ 73 Other income 749 Total net earnings (loss) $ 822

Dividend Restrictions and Statu

Dividend Restrictions and Statutory Financial Information	12 Months Ended
	Dec. 31, 2019
Insurance [Abstract]
Dividend Restrictions and Statutory Financial Information	22. DIVIDEND RESTRICTIONS AND STATUTORY FINANCIAL INFORMATION Parent Company Dividend Restrictions There were no significant restrictions on the Parent Company's ability to pay dividends from retained earnings as of December 31, 2019 . Bermuda law permits the payment of dividends if (i) we are not, or would not be after payment, unable to pay our liabilities as they become due and (ii) the realizable value of our assets is in excess of our liabilities after taking such payment into account. We have not historically declared a dividend on our ordinary shares. The issuance of our Series D and E Preferred Shares have resulted in the declaration of dividends. Holders of Series D and Series E Preferred Shares are entitled to receive, only when, as and if declared, non-cumulative cash dividends, paid quarterly in arrears on the 1st day of March, June, September and December of each year of 7.0% per annum. Refer to Note 17 - "Share Capital" for details regarding dividends on preferred shares. The Bermuda Monetary Authority ("BMA") acts as group supervisor to Enstar. On an annual basis, we are required to file group statutory financial statements, a group statutory financial return, a group capital and solvency return, audited group financial statements and a Group Solvency Self-Assessment ("GSSA") with the BMA. The GSSA is designed to document our perspective on the capital resources necessary to achieve our business strategies and remain solvent, and to provide the BMA with insights on our risk management, governance procedures and documentation related to this process. We are required to maintain available group statutory capital and surplus in an amount that is at least equal to the group enhanced capital requirement ("Group ECR"). The BMA has also established a group target capital level equal to 120% of the Group ECR. We are in compliance with these requirements. Our ability to pay dividends to our shareholders is dependent upon the ability of our insurance and reinsurance subsidiaries to distribute capital and pay dividends to us. Our insurance and reinsurance subsidiaries are subject to certain regulatory restrictions on the distribution of capital and payment of dividends in the jurisdictions in which they operate, as described below. The restrictions are generally based on net income or levels of capital and surplus as determined in accordance with the relevant statutory accounting practices. Failure of these subsidiaries to meet their applicable regulatory requirements could result in restrictions on any distributions of capital or retained earnings or stricter regulatory oversight of the subsidiaries. Our ability to pay dividends and make other forms of distributions may also be limited by repayment obligations and financial covenants in our outstanding loan facility agreements. Subsidiary Statutory Financial Information and Dividend Restrictions Our insurance and reinsurance subsidiaries prepare their statutory financial statements in accordance with statutory accounting practices prescribed or permitted by local regulators. Statutory accounting differs from U.S. GAAP, including in the treatment of investments, acquisition costs and deferred income taxes, amongst other items. The statutory capital and surplus amounts for the years ended December 31, 2019 and 2018 and statutory net income amounts for the years ended December 31, 2019 , 2018 and 2017 for our insurance and reinsurance subsidiaries based in Bermuda, the United Kingdom, Australia, the United States and Continental Europe are summarized in the table below which includes information relating to acquisitions from the year of acquisition: Statutory Capital and Surplus Required Actual Statutory Income 2019 2018 2019 2018 2019 2018 2017 Bermuda $ 2,138,395 $ 1,591,991 $ 4,016,663 $ 3,701,825 $ 643,683 $ 29,486 $ 390,752 U.K. 837,104 654,721 1,532,751 715,448 154,644 (52,936 ) 77,900 U.S. 364,507 392,394 861,379 660,470 121,406 (75,005 ) (5,065 ) Europe 94,334 239,582 229,344 431,863 11,816 (17,611 ) (4,245 ) Australia 18,110 22,535 37,815 26,882 4,847 1,761 (874 ) As of December 31, 2019 , the total amount of net assets of our consolidated subsidiaries that were restricted was $3.5 billion . Certain material aspects of these laws and regulations as they relate to solvency, dividends and capital and surplus are summarized below. Bermuda Our Bermuda-based insurance and reinsurance subsidiaries are registered under the Insurance Act 1978 of Bermuda and related regulations, as amended (the "Insurance Act"). The Insurance Act imposes certain solvency and liquidity standards and auditing and reporting requirements and grants the BMA powers to supervise, investigate, require information and the production of documents and intervene in the affairs of insurance companies. The Insurance Act requires that our Bermuda-based insurance and reinsurance subsidiaries maintain certain solvency and liquidity standards. The minimum liquidity ratio requires that the value of relevant assets not be less than 75% of the amount of relevant liabilities. The minimum solvency margin, which varies depending on the class of the insurer, is determined as a percentage of either net reserves for losses and LAE or premiums or pursuant to a risk-based capital measure. Our Bermuda subsidiaries with commercial insurance licenses are required to maintain a minimum statutory capital and surplus (Enhanced Capital Requirement or "ECR") at least equal to the greater of a minimum solvency margin or the Bermuda Solvency Capital Requirement ("BSCR"). The BSCR is calculated based on a standardized risk-based capital model. Each of our regulated Bermuda subsidiaries would be prohibited from declaring or paying any dividends if it were in breach of its minimum solvency margin or liquidity ratio or if the declaration or payment of such dividends would cause it to fail to meet such margin or ratio. In addition, each of our regulated Bermuda subsidiaries is prohibited, without the prior approval of the BMA, from reducing by 15% or more its total statutory capital, or from reducing by 25% of more its total statutory capital and surplus, as set out in its previous year’s statutory financial statements. Our Bermuda insurance companies that are in run-off are required to seek BMA approval for any dividends or distributions. As of December 31, 2019 and 2018 , each of our Bermuda-based insurance and reinsurance subsidiaries exceeded their respective minimum solvency and liquidity requirements. The Bermuda insurance and reinsurance subsidiaries in aggregate exceeded minimum solvency requirements by $1.9 billion as of December 31, 2019 ( 2018 : $2.1 billion ) and were in compliance with their liquidity requirements. United Kingdom U.K. Insurance Companies (non-Lloyd's) Our U.K. based insurance subsidiaries are regulated by the U.K. Prudential Regulatory Authority (the "PRA") and the Financial Conduct Authority (the "FCA", together with the PRA, the "U.K. Regulator"). Our U.K.-based insurance subsidiaries are required to maintain adequate financial resources in accordance with the requirements of the U.K. Regulator. Insurers must comply with a Solvency Capital Requirement ("SCR"), which is calculated using either the Solvency II standard formula or a bespoke internal model. Our non-Lloyd's U.K. companies use the standard formula. The calculation of the minimum capital resources requirements in any particular case depends on, among other things, the type and amount of insurance business written and claims paid by the insurance company. As of December 31, 2019 and 2018 , all of our U.K. insurance subsidiaries maintained capital in excess of the minimum capital resources requirements and complied with the relevant U.K. Regulator requirements. The U.K.-based insurance subsidiaries, in aggregate, maintained capital in excess of the minimum capital resources requirements by $695.6 million and $60.7 million as of December 31, 2019 and 2018 , respectively. The U.K. Regulator’s rules require our U.K. insurance subsidiaries to obtain regulatory approval for any proposed or actual payment of a dividend. The U.K. Regulator uses the SCR, among other tests, when assessing requests to make distributions. Lloyd’s As of December 31, 2019 , we participated in the Lloyd’s market through our interests in: (i) Atrium’s Syndicate 609, which is managed by Atrium Underwriters Limited, a Lloyd's managing agent, and the Atrium corporate member; (ii) StarStone’s Syndicate 1301, which is managed by StarStone Underwriting Limited ("SUL"), a Lloyd’s managing agent, and the StarStone corporate member; and (iii) Syndicate 2008, a wholly aligned syndicate that has permission to underwrite RITC business and other run-off or discontinued business type transactions with other Lloyd’s syndicates, and its corporate member. During 2015, SUL assumed the role of managing agent for Syndicate 2008 in place of Shelbourne Syndicate Services Limited as we streamlined our organizational structure and combined Shelbourne and StarStone resources into one agency. For the 2019 underwriting year, participation in all three syndicates has been through a common corporate member. The underwriting capacity of a member of Lloyd’s is supported by providing Funds at Lloyd’s, as described in Note 6 - "Investments" . Business plans, including maximum underwriting capacity, for Lloyd’s syndicates requires annual approval by the Lloyd’s Franchise Board, which may require changes to any business plan or additional capital to support underwriting plans. The Lloyd’s market has applied the Solvency II internal model under Lloyd’s supervision, and our Lloyd’s operations are required to meet Solvency II standards. Lloyd's has the approval of the PRA to use its internal model under the Solvency II regime. United States Our U.S. non-life run-off and active underwriting insurance and reinsurance subsidiaries are subject to the insurance laws and regulations of the states in which they are domiciled, licensed and/or eligible to conduct business. These laws restrict the amount of dividends the subsidiaries can pay to us. The restrictions are generally based on statutory net income and/or certain levels of statutory surplus as determined in accordance with the relevant statutory accounting requirements of the individual domiciliary states or states in which any of the insurance or reinsurance subsidiaries are domiciled. Generally, prior regulatory approval must be obtained before an insurer may pay a dividend or make a distribution above a specified level. The U.S. insurance and reinsurance subsidiaries are also required to maintain minimum levels of solvency and liquidity as determined by law, and to comply with Risk-Based Capital ("RBC") requirements and licensing rules as specified by the National Association of Insurance Commissioners ("NAIC"). RBC is used to evaluate the adequacy of capital and surplus maintained by our life company in relation to risks associated with: (i) asset risk; (ii) insurance risk; (iii) interest rate risk and (iv) business risk. For all of our U.S. insurance and reinsurance subsidiaries, with the exception of one subsidiary which has a permitted accounting practice to treat an adverse development cover reinsurance agreement as prospective reinsurance, there are no prescribed or permitted statutory accounting practices that differ significantly from the statutory accounting principles established by NAIC. As of December 31, 2019 , all of our U.S. non-life insurance and reinsurance subsidiaries exceeded their required levels of risk-based capital. On an aggregate basis, our U.S. non-life insurance and reinsurance subsidiaries exceeded their minimum levels of risk-based capital as of December 31, 2019 by $488.3 million ( December 31, 2018 : $359.6 million ). Europe Our Liechtenstein insurance subsidiary (StarStone Insurance SE) is regulated by the Liechtenstein Financial Market Authority ("FMA") pursuant to the Liechtenstein Insurance Supervisory Act. This subsidiary is obligated to maintain a minimum solvency margin based on the Solvency II regulations. As of December 31, 2019 , this subsidiary exceeded th e Solvency II requirements by $119.0 million ( 2018 : $133.9 million). The amount of dividends that this subsidiary is permitted to distribute is restricted to freely distributable reserves, which consist of retained earnings, the current year profit and legal reserves. Any dividend exceeding the current year profit requires the FMA’s approval. Solvency and capital requirements for this subsidiary are based on the Solvency II framework and must continue to be met following any distribution. Our Belgian insurance subsidiary files financial statements and returns with the National Bank of Belgium. This subsidiary was in compliance with its solvency and capital requirements under Solvency II. Harper Insurance Limited, which was previously regulated in Switzerland, was re-domiciled to Bermuda on January 1, 2019. It is now required to file regulatory returns in both Bermuda and for its branch in the UK. The UK requirements are more constrictive then those in Bermuda thus these have been included in the "United Kingdom" section above.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	23. COMMITMENTS AND CONTINGENCIES Concentration of Credit Risk We believe that there are no significant concentrations of credit risk associated with our cash and cash equivalents, fixed maturity investments, or other investments. Cash, cash equivalents and fixed maturity investments are managed pursuant to guidelines that follow prudent standards of diversification and limit the allowable holdings of a single issue and issuers. Other investments are managed pursuant to guidelines that emphasize diversification and liquidity. Pursuant to these guidelines, we manage and monitor risk across a variety of investment funds and vehicles, markets and counterparties. We are also subject to custodial credit risk on our investments, which we manage by diversifying our holdings amongst large financial institutions that are highly regulated. We have exposure to credit risk on certain of our assets pledged to ceding companies under insurance contracts. In addition, we are potentially exposed should any insurance intermediaries be unable to fulfill their contractual obligations with respect to payments of balances owed to and by us. Credit risk exists in relation to our insurance and reinsurance balances recoverable on paid and unpaid losses. We remain liable to the extent that counterparties do not meet their contractual obligations and, therefore, we evaluate and monitor concentration of credit risk among our insurers and reinsurers. Amounts recoverable from reinsurers are described Note 8 - "Reinsurance Balances Recoverable on Paid and Unpaid Losses" . We are also subject to credit risk in relation to funds held by reinsured companies. Under funds held arrangements, the reinsured company has retained funds that would otherwise have been remitted to our reinsurance subsidiaries. The funds may be placed into trust or subject to other security arrangements. The funds balance is credited with investment income and losses payable are deducted. We are subject to credit risk if the reinsured company is unable to honor the value of the funds held balances, such as in the event of insolvency. However, we generally have the contractual ability to offset any shortfall in the payment of the funds held balances with amounts owed by us to the reinsured for losses payable and other amounts contractually due. We routinely monitor the creditworthiness of reinsured companies with whom we have funds held arrangements. We have a significant funds held concentration of $1.0 billion to one reinsured company which has financial strength credit ratings of A+ from A.M. Best and AA from S&P. We limit the amount of credit exposure to any one counterparty and none of our counterparty credit exposures, excluding U.S. Government instruments and the counterparty noted above, exceeded 10% of shareholders’ equity as of December 31, 2019 . Our credit exposure to the U.S. government was $1,082.2 million as of December 31, 2019 . Legal Proceedings We are, from time to time, involved in various legal proceedings in the ordinary course of business, including litigation and arbitration regarding claims. Estimated losses relating to claims arising in the ordinary course of business, including the anticipated outcome of any pending arbitration or litigation are included in the liability for losses and LAE in our consolidated balance sheets. In addition to claims litigation, we may be subject to other lawsuits and regulatory actions in the normal course of business, which may involve, among other things, allegations of underwriting errors or omissions, employment claims or regulatory activity. We do not believe that the resolution of any currently pending legal proceedings, either individually or taken as a whole, will have a material effect on our business, results of operations or financial condition. We anticipate that, similar to the rest of the insurance and reinsurance industry, we will continue to be subject to litigation and arbitration proceedings in the ordinary course of business, including litigation generally related to the scope of coverage with respect to asbestos and environmental and other claims. Unfunded Investment Commitments As of December 31, 2019 , we had unfunded commitments of $482.3 million and $93.1 million to private equity funds and equity method investments, respectively. Guarantees As of December 31, 2019 and 2018 , parental guarantees and capital instruments supporting subsidiaries' insurance obligations were $1,031.5 million and $614.5 million , respectively. We also have a FAL facility, which on February 12, 2019, we increased to issue an aggregate amount of $375.0 million of letters of credit, and we maintained the provision to further increase the facility up to $400.0 million . The FAL Facility is available to satisfy our Funds at Lloyd’s requirements and expires in 2023. As of December 31, 2019 there were $252.0 million Significant New Business We have entered into transaction agreements that are expected to become effective subsequent to December 31, 2019 . Refer to Note 4 - "Significant New Business" above. Redeemable Noncontrolling Interest We have the right to purchase the RNCI interests from the RNCI holders at certain times in the future (each such right, a "call right") and the RNCI holders have the right to sell their RNCI interests to us at certain times in the future (each such right, a "put right"). The RNCI rights held by Trident are described in Note 21 - "Related Party Transactions" . Dowling has a right to participate if Trident exercises its put right. Leases 2019 Disclosures under ASC 842 - Leases We adopted the new leasing standard and the related amendments on January 1, 2019 using the modified retrospective transition method as required by the standard, and based on the detailed analysis of our operating lease arrangements we have recognized a right-of-use asset and an offsetting lease liability on our consolidated balance sheet, relating primarily to office space and facilities that we have leased to conduct our business operations. On an ongoing basis w e determine whether an arrangement is a lease or contains a lease at inception and also complete an assessment to determine the classification of each lease as either a finance lease or an operating lease. Our leases are all currently classified as operating leases. Our leases have remaining lease terms of one year to 37 years, some of which include options to extend the lease term for up to five years and some of which include options to terminate the lease within one year. We consider these options in determining the lease term used to establish our right-of-use assets and lease liabilities. Only those renewal options that we believe we are reasonably certain to exercise are taken into account when determining lease terms. Our lease agreements do not contain any material residual value guarantees or material restrictive covenants. Since a majority of our leases do not provide an implicit discount rate, we use our collateralized incremental borrowing rate based on the information available at the commencement date of the lease in determining the present value of lease payments. The starting point for determining a collateralized incremental borrowing rate is our general unsecured borrowing rate, given the term of the lease and the amount of the related lease payments. This base rate is then adjusted to reflect the effect of collateral. Since adding collateral improves a lender’s level of security in a lending arrangement, it has the impact of lowering our implied borrowing rate that we use to determine the present value of lease payments. We also adopt a portfolio approach as permitted by ASC 842 whereby we use attributes such as the lease term to determine the appropriate incremental borrowing rate to be used to determine the present value of lease payments. In this regard, we use the same incremental borrowing rate for leases with a similar term while ensuring that the use of this portfolio approach does not result in an outcome that would materially differ from applying the lease accounting guidance on a lease-by-lease basis. We have lease agreements that contain both lease and non-lease components. For real estate leases, we account for lease components together with non-lease components such as common-area maintenance costs as a single lease component. As part of our adoption of the new leasing standard, we elected the practical expedient package as well as the hindsight practical expedient permitted by the FASB in ASC 842. The practical expedient package covers the application of the new leasing standard to leases that commenced before January 1, 2019, the effective date of the standard and gives an entity the option of not reassessing, (1) whether any expired or existing contracts are or contain leases, (2) the lease classification for any expired or existing leases, and (3) initial direct costs for any existing leases. The hindsight practical expedient permits an entity to consider changes in facts and circumstances from commencement through to the effective date of the new standard when determining the lease term and assessing any potential impairment of the recorded right-of-use asset. All these practical expedients were consistently applied to our leases as required by the leasing standard. The table below provides a summary of the compon ents of our lease cost including the gross sublease income received under sublease arrangements related to certain office spaces that we have leased to conduct our business operations for the year ended December 31, 2019 : 2019 Operating lease cost $ 13,627 Sublease income (542 ) Total lease cost $ 13,085 The table below provides a summary of the cash flow information and non-cash activity related to our operating leases for the year ended December 31, 2019 : 2019 Operating cash flow information: Cash paid for amounts included in the measurement of lease liabilities $ 11,129 Non-cash activity: Right-of-use assets obtained in exchange for lease obligations $ 57,536 The table below provides a summary of the leases recorded on our consolidated balance sheets for the year ended December 31, 2019 : Balance sheet classification 2019 Right-of-use assets Other assets $ 46,747 Current lease liabilities Other liabilities 11,403 Non-current lease liabilities Other liabilities 34,785 Weighted-average remaining lease term and discount rate used for our operating leases are as follows for the year ended December 31, 2019 : 2019 Weighted-average remaining lease term 6.3 years Weighted-average discount rate 6.3 % The table below provides a summary of the maturity of the operating lease liabilities for the year ended December 31, 2019 : 2019 2020 $ 13,663 2021 9,854 2022 8,103 2023 7,044 2024 5,358 2025 and beyond 13,119 Total lease payments 57,141 Less: Imputed interest (10,953 ) Present value of lease liabilities $ 46,188 2018 Comparative Disclosures under ASC 840 - Leases As discussed in Note 2 - Significant Accounting Policies, on adoption of ASU 2016-02 as codified in ASC 842 on January 1, 2019, we elected the transition option in ASU 2018-11 which amended ASU 2016-02 to allow entities not to apply the new leases standard in the comparative periods presented in the financial statements in the year of adoption. Under the transition option, entities can instead opt to continue to apply the legacy guidance in ASC 840 - Leases , including its disclosure requirements, in the comparative periods presented in the year they adopt the new leases standard. Pursuant to the transition option provided in ASU 2018-11 which we elected on adoption of ASU 2016-02 on January 1, 2019 as discussed above, the following is a schedule of future minimum rental payments that were required under operating leases that had initial or remaining non-cancelable lease terms in excess of one year as of December 31, 2018: 2019 $ 9,510 2020 10,754 2021 9,772 2022 7,500 2023 6,592 2024 and beyond 21,276 $ 65,404 Rent expense for the years ended December 31, 2018 and 2017 was $11.3 million and $9.5 million , respectively, relating to office space and facilities that we leased to conduct our business operations .

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment Information	24. SEGMENT INFORMATION We have three reportable segments of business that are each managed, operated and separately reported: (i) Non-life Run-off; (ii) Atrium; and (iii) StarStone. Our other activities, which do not qualify as a reportable segment, include our corporate expenses, debt servicing costs, holding company income and expenses, foreign exchange and other miscellaneous items. These segments are described in Note 1 - "Description of Business" . The following tables set forth selected and consolidated statement of earnings results by segment for the years ended December 31, 2019 , 2018 , 2017 : 2019 Non-Life Run-Off Atrium StarStone Other Total Gross premiums written $ (25,069 ) $ 192,373 $ 917,555 $ 18,534 $ 1,103,393 Net premiums written $ (25,338 ) $ 172,356 $ 735,429 $ 18,512 $ 900,959 Net premiums earned $ 168,496 $ 164,059 $ 801,926 $ 20,380 $ 1,154,861 Net incurred losses and LAE (51,625 ) (77,276 ) (727,636 ) (16,038 ) (872,575 ) Life and Annuity Policy Benefits — — — (91 ) (91 ) Acquisition costs (73,642 ) (56,956 ) (174,711 ) (642 ) (305,951 ) Operating expenses (199,756 ) (14,452 ) (120,629 ) — (334,837 ) Underwriting income (loss) (156,527 ) 15,375 (221,050 ) 3,609 (358,593 ) Net investment income 275,236 7,049 47,401 (8,410 ) 321,276 Net realized and unrealized gains 968,350 6,195 50,957 5,849 1,031,351 Fees and commission income 18,293 10,160 — — 28,453 Other income 34,809 140 338 1,883 37,170 Corporate expenses (70,689 ) (13,825 ) (7,790 ) (45,945 ) (138,249 ) Interest income (expense) (62,055 ) — (475 ) 9,989 (52,541 ) Net foreign exchange gains (losses) 9,918 (504 ) (1,538 ) 3 7,879 EARNINGS (LOSS) BEFORE INCOME TAXES 1,017,335 24,590 (132,157 ) (33,022 ) 876,746 Income tax benefit (expense) (7,250 ) (4,033 ) 6,931 (85 ) (4,437 ) Earnings (losses) from equity method investments 56,128 — (218 ) — 55,910 NET EARNINGS (LOSS) 1,066,213 20,557 (125,444 ) (33,107 ) 928,219 Net loss (earnings) attributable to noncontrolling interest (6,409 ) (8,432 ) 24,711 — 9,870 NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED 1,059,804 12,125 (100,733 ) (33,107 ) 938,089 Dividends on preferred shares — — — (35,914 ) (35,914 ) NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS $ 1,059,804 $ 12,125 $ (100,733 ) $ (69,021 ) $ 902,175 Underwriting ratios: Loss ratio 47.1 % 90.7 % Acquisition expense ratio 34.7 % 21.8 % Operating expense ratio 8.8 % 15.1 % Combined ratio 90.6 % 127.6 % 2018 Non-Life Run-Off Atrium StarStone Other Total Gross premiums written $ (8,910 ) $ 171,494 $ 1,121,135 $ 32,378 $ 1,316,097 Net premiums written $ (9,217 ) $ 153,488 $ 805,562 $ 32,067 $ 981,900 Net premiums earned $ 9,427 $ 146,315 $ 714,959 $ 24,874 $ 895,575 Net incurred losses and LAE 306,067 (69,810 ) (673,383 ) (16,899 ) (454,025 ) Life and annuity policy benefits — — — (1,003 ) (1,003 ) Acquisition costs (4,006 ) (50,646 ) (135,452 ) (2,686 ) (192,790 ) Operating expenses (158,731 ) (17,777 ) (156,726 ) — (333,234 ) Underwriting income (loss) 152,757 8,082 (250,602 ) 4,286 (85,477 ) Net investment income 226,287 5,686 35,973 2,725 270,671 Net realized and unrealized losses (381,712 ) (3,251 ) (17,672 ) (10,249 ) (412,884 ) Fees and commission income 16,466 18,622 — — 35,088 Other income (losses) 35,978 162 (541 ) (514 ) 35,085 Corporate expenses (39,093 ) (6,921 ) — (28,127 ) (74,141 ) Interest income (expense) (30,616 ) — (624 ) 5,023 (26,217 ) Net foreign exchange gains (losses) 2,534 (3,394 ) (2,856 ) 1,048 (2,668 ) EARNINGS (LOSS) BEFORE INCOME TAXES (17,399 ) 18,986 (236,322 ) (25,808 ) (260,543 ) Income tax benefit (expense) 3,581 (3,732 ) 6,327 (52 ) 6,124 Earnings from equity method investments 42,147 — — — 42,147 NET EARNINGS (LOSS) 28,329 15,254 (229,995 ) (25,860 ) (212,272 ) Net loss (earnings) attributable to noncontrolling interest (3,107 ) (6,257 ) 71,415 — 62,051 NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED 25,222 8,997 (158,580 ) (25,860 ) (150,221 ) Dividends on preferred shares — — — (12,133 ) (12,133 ) NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS $ 25,222 $ 8,997 $ (158,580 ) $ (37,993 ) $ (162,354 ) Underwriting ratios: Loss ratio 47.7 % 94.2 % Acquisition expense ratio 34.6 % 18.9 % Operating expense ratio 12.2 % 22.0 % Combined ratio 94.5 % 135.1 % 2017 Non-Life Run-Off Atrium StarStone Other Total Gross premiums written $ 14,102 $ 153,472 $ 895,160 $ 5,719 $ 1,068,453 Net premiums written $ 6,482 $ 134,214 $ 464,901 $ 4,793 $ 610,390 Net premiums earned $ 14,162 $ 134,747 $ 459,403 $ 4,809 $ 613,121 Net incurred losses and LAE 190,674 (69,419 ) (314,806 ) — (193,551 ) Life and annuity policy benefits — — — (4,015 ) (4,015 ) Acquisition costs (328 ) (47,688 ) (48,012 ) (878 ) (96,906 ) Operating expenses (132,235 ) (17,444 ) (135,558 ) — (285,237 ) Underwriting income (loss) 72,273 196 (38,973 ) (84 ) 33,412 Net investment income 166,678 4,218 27,706 10,187 208,789 Net realized and unrealized gains (losses) 179,545 1,117 16,613 (6,941 ) 190,334 Fees and commission income (expense) 43,849 22,788 632 (1,166 ) 66,103 Other income 21,157 230 570 648 22,605 Corporate expenses (101,592 ) (12,142 ) — (37,014 ) (150,748 ) Interest income (expense) (28,970 ) (559 ) (1,902 ) 3,329 (28,102 ) Net foreign exchange gains (7,347 ) (5,060 ) (926 ) (4,204 ) (17,537 ) Loss on sale of subsidiary — — — (16,349 ) (16,349 ) EARNINGS (LOSS) BEFORE INCOME TAXES 345,593 10,788 3,720 (51,594 ) 308,507 Income tax benefit (expense) 6,990 (1,593 ) 988 10 6,395 Earnings from equity method investments 5,904 — — — 5,904 NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS 358,487 9,195 4,708 (51,584 ) 320,806 Net earnings from discontinued operations, net of income taxes — — — 10,993 10,993 NET EARNINGS (LOSS) 358,487 9,195 4,708 (40,591 ) 331,799 Net earnings attributable to noncontrolling interest (14,687 ) (3,772 ) (1,882 ) — (20,341 ) NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS $ 343,800 $ 5,423 $ 2,826 $ (40,591 ) $ 311,458 Underwriting ratios: Loss ratio 51.5 % 68.5 % Acquisition expense ratio 35.4 % 10.5 % Operating expense ratio 13.0 % 29.5 % Combined ratio 99.9 % 108.5 % Gross Premiums Written by Geographical Area The following table summarizes our gross premiums written for the year ended December 31, 2019 by geographic area. Geographic distribution in future years is subject to variation based upon market conditions and business strategies. Non-life Run-off Atrium StarStone Other Total Total % Total % Total % Total % Total % (In thousands of U.S. dollars, except percentages) United States $ (25,012 ) 99.7 % $ 102,199 53.1 % $ 548,683 59.8 % $ 17,239 93.0 % $ 643,109 58.2 % United Kingdom 350 (1.4 )% 12,972 6.7 % 114,822 12.5 % — — % 128,144 11.6 % Europe (265 ) 1.1 % 17,677 9.2 % 115,481 12.6 % 1,295 7.0 % 134,188 12.2 % Asia (48 ) 0.2 % 5,700 3.0 % 75,773 8.3 % — — % 81,425 7.4 % Rest of World (94 ) 0.4 % 53,825 28.0 % 62,796 6.8 % — — % 116,527 10.6 % Total $ (25,069 ) 100.0 % $ 192,373 100.0 % $ 917,555 100.0 % $ 18,534 100.0 % $ 1,103,393 100.0 % Assets by Segment Invested assets are managed on a subsidiary by subsidiary basis, and investment income and realized and unrealized gains on investments are recognized in each segment as earned. Our total assets as of December 31, 2019 and 2018 by segment were as follows: 2019 2018 Assets by Segment: Non-life Run-off $ 15,775,409 $ 13,362,749 Atrium 580,405 591,722 StarStone 3,522,353 3,416,132 Other (514,852 ) (814,333 ) Total assets $ 19,363,315 $ 16,556,270

Unaudited Condensed Quarterly F

Unaudited Condensed Quarterly Financial Data	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Unaudited Condensed Quarterly Financial Data	25. UNAUDITED CONDENSED QUARTERLY FINANCIAL DATA December 31, September 30, June 30, March 31, 2019 2018 2019 2018 2019 2018 2019 2018 INCOME Net premiums earned $ 272,686 $ 231,947 $ 270,325 $ 264,597 $ 276,563 $ 228,812 $ 335,287 $ 170,219 Fees and commission income 9,007 11,455 6,587 6,950 6,178 8,352 6,681 8,331 Net investment income 79,376 68,453 85,472 69,430 77,732 66,469 78,696 66,319 Net realized and unrealized gains (losses) 152,664 (158,213 ) 148,185 (57,223 ) 269,711 (54,418 ) 460,791 (143,030 ) Other income (losses) 19,502 34,267 826 8,226 11,030 (9,351 ) 5,812 1,943 533,235 187,909 511,395 291,980 641,214 239,864 887,267 103,782 EXPENSES Net incurred losses and loss adjustment expenses 121,416 187,698 222,417 153,974 216,338 92,819 312,404 19,534 Life and annuity policy benefits (2,199 ) 786 — 423 2,194 (160 ) 96 (46 ) Acquisition costs 95,026 55,106 50,282 54,242 66,855 53,334 93,788 30,108 General and administrative expenses 129,569 106,950 113,924 102,553 117,519 102,612 112,074 95,260 Interest expense 13,519 4,644 14,950 4,640 13,036 8,922 11,036 8,011 Net foreign exchange losses (gains) 12,189 1,279 (13,631 ) 1,040 (2,587 ) (5,519 ) (3,850 ) 5,868 369,520 356,463 387,942 316,872 413,355 252,008 525,548 158,735 EARNINGS (LOSS) BEFORE INCOME TAXES 163,715 (168,554 ) 123,453 (24,892 ) 227,859 (12,144 ) 361,719 (54,953 ) Income tax benefit (expense) 22,427 10,688 (14,597 ) (746 ) (7,518 ) (3,646 ) (4,749 ) (172 ) Earnings from equity method investments 11,722 8,488 17,703 3,317 17,713 15,645 8,772 14,697 NET EARNINGS (LOSS) 197,864 (149,378 ) 126,559 (22,321 ) 238,054 (145 ) 365,742 (40,428 ) Net loss (earnings) attributable to noncontrolling interest 4,900 42,955 109 11,489 2,713 8,389 2,148 (782 ) NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED 202,764 (106,423 ) 126,668 (10,832 ) 240,767 8,244 367,890 (41,210 ) Dividends on preferred shares (8,925 ) (7,000 ) (8,925 ) (5,133 ) (8,925 ) — (9,139 ) — NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS $ 193,839 $ (113,423 ) $ 117,743 $ (15,965 ) $ 231,842 $ 8,244 $ 358,751 $ (41,210 ) Earnings Loss) per ordinary share attributable to Enstar Group Limited: Basic $ 9.02 $ (5.29 ) $ 5.48 $ (0.74 ) $ 10.79 $ 0.40 $ 16.71 $ (2.12 ) Diluted (1) : $ 8.89 $ (5.29 ) $ 5.42 $ (0.74 ) $ 10.70 $ 0.40 $ 16.57 $ (2.12 ) (1) During a period of loss, the basic weighted average ordinary shares outstanding is used in the denominator of the diluted loss per ordinary share computation as the effect of including potentially dilutive securities would be anti-dilutive.

Schedule I - Summary of Investm

Schedule I - Summary of Investments Other Than Investments in Related Parties	12 Months Ended
	Dec. 31, 2019
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract]
Schedule I - Summary of Investments Other Than Investments in Related Parties	SCHEDULE I ENSTAR GROUP LIMITED SUMMARY OF INVESTMENTS OTHER THAN INVESTMENTS IN RELATED PARTIES As of December 31, 2019 (Expressed in thousands of U.S. Dollars) Type of investment Cost (1) Fair Value Amount at which shown in the balance sheet Fixed maturity securities and short-term investments — Trading and fixed maturity investments within funds held - directly managed: (2) U.S. government and agency $ 319,554 $ 325,731 $ 325,731 U.K. government 140,194 146,423 146,423 Other government 600,001 617,710 617,710 Corporate 4,398,126 4,615,896 4,615,896 Municipal 141,905 152,010 152,010 Residential mortgage-backed 339,228 344,617 344,617 Commercial mortgage-backed 783,675 801,472 801,472 Asset-backed 562,020 558,217 558,217 Total 7,284,703 7,562,076 7,562,076 Fixed maturity securities and short-term investments — Available-for-sale: (2) U.S. government and agency 410,842 410,312 410,312 U.K. government 15,067 15,349 15,349 Other government 84,116 85,147 85,147 Corporate 1,081,713 1,081,171 1,081,171 Municipal 15,963 15,872 15,872 Residential mortgage-backed 127,704 127,219 127,219 Commercial mortgage-backed 98,928 98,557 98,557 Asset-backed 202,136 202,117 202,117 Total 2,036,469 2,035,744 2,035,744 Equities (3) 312,407 367,812 367,812 Other investments, at fair value (4) 783,032 783,032 783,032 Total $ 10,416,611 $ 10,748,664 $ 10,748,664 (1) Original cost of fixed maturity securities is reduced by repayments and adjusted for amortization of premiums or accretion of discounts. (2) The difference in the amount of fixed maturities shown at fair value and the fixed maturities shown in our consolidated balance sheet relates to the fair value of $15.1 million as of December 31, 2019 for our investment in fixed maturities issued by affiliates of Stone Point. Refer to Note 21 - "Related Party Transactions" of the notes to the consolidated financial statements. (3) The difference in the amount of equities shown at fair value and the equities shown in our consolidated balance sheet relates to the fair value of $96.8 million as of December 31, 2019 for our investment in a registered investment company affiliated with entities owned by Trident, $25.0 million as a co-investor alongside Stone Point and a $240.1 million investment in AmTrust. Refer to Note 21 - "Related Party Transactions" of the notes to the consolidated financial statements. (4) The difference in the amount of other investments shown at fair value and the other investments shown in our consolidated balance sheet relates to the fair value of $1,741.4 million as of December 31, 2019 for our other investments in funds or companies owned by or affiliated with certain related parties. Refer to Note 21 - "Related Party Transactions" of the notes to the consolidated financial statements.

Schedule II - Condensed Financi

Schedule II - Condensed Financial Statements	12 Months Ended
	Dec. 31, 2019
Condensed Financial Information Disclosure [Abstract]
Schedule II - Condensed Financial Statements	SCHEDULE II ENSTAR GROUP LIMITED CONDENSED FINANCIAL INFORMATION OF REGISTRANT Balance Sheets - Parent Company Only As of December 31, 2019 and 2018 2019 2018 (in thousands of U.S. dollars, except share data) ASSETS Cash and cash equivalents $ 4,568 $ 15,213 Balances due from subsidiaries 134,897 25,091 Investments in subsidiaries 6,050,197 4,843,913 Other assets 6,391 8,596 TOTAL ASSETS $ 6,196,053 $ 4,892,813 LIABILITIES Debt obligations $ 1,191,207 $ 861,539 Balances due to subsidiaries 135,532 120,397 Other liabilities 27,131 8,944 TOTAL LIABILITIES 1,353,870 990,880 COMMITMENTS AND CONTINGENCIES SHAREHOLDERS’ EQUITY Ordinary shares (par value $1 each, issued and outstanding 2019: 21,511,505; 2018: 21,459,997): Voting Ordinary Shares (issued and outstanding 2019: 18,001,823; 2018: 17,950,315) 18,002 17,950 Non-voting convertible ordinary Series C Shares (issued and outstanding 2019 and 2018: 2,599,672) 2,600 2,600 Non-voting convertible ordinary Series E Shares (issued and outstanding 2019 and 2018: 910,010) 910 910 Preferred Shares: Series C Preferred Shares (issued and held in treasury 2019 and 2018: 388,571) 389 389 Series D Preferred Shares (issued and outstanding 2019 and 2018: 16,000) 400,000 400,000 Series E Preferred Shares (issued and outstanding 2019 and 2018: 4,400) 110,000 110,000 Treasury shares, at cost (Series C Preferred Shares 2019 and 2018: 388,571) (421,559 ) (421,559 ) Additional paid-in capital 1,836,778 1,804,664 Accumulated other comprehensive income 7,171 10,440 Retained earnings 2,887,892 1,976,539 Total Enstar Group Limited Shareholders’ Equity 4,842,183 3,901,933 TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY $ 6,196,053 $ 4,892,813 See accompanying notes to the Condensed Financial Information of Registrant SCHEDULE II ENSTAR GROUP LIMITED CONDENSED FINANCIAL INFORMATION OF REGISTRANT - CONTINUED Statements of Earnings - Parent Company Only For the Years Ended December 31, 2019 , 2018 and 2017 2019 2018 2017 (in thousands of U.S. dollars) INCOME Net investment income $ 3,649 $ 142 $ 80 Other income — — 1,050 Dividend income from subsidiaries — — 249,055 3,649 142 250,185 EXPENSES General and administrative expenses 44,964 68,977 87,596 Interest expense 51,508 27,353 23,138 Net foreign exchange losses (gains) (21,516 ) 7,655 6,135 74,956 103,985 116,869 EARNINGS (LOSSES) BEFORE EQUITY IN UNDISTRIBUTED EARNINGS OF SUBSIDIARIES (71,307 ) (103,843 ) 133,316 Equity in undistributed earnings (losses) of subsidiaries - continuing operations 1,009,396 (46,378 ) 167,149 Equity in undistributed earnings (losses) of subsidiaries - discontinued operations — — 10,993 NET EARNINGS 938,089 (150,221 ) 311,458 Dividends on preferred shares (35,914 ) (12,133 ) — NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS $ 902,175 $ (162,354 ) $ 311,458 See accompanying notes to the Condensed Financial Information of Registrant Statements of Comprehensive Income - Parent Company Only For the Years Ended December 31, 2019 , 2018 and 2017 2019 2018 2017 (in thousands of U.S. dollars) NET EARNINGS $ 938,089 $ (150,221 ) $ 311,458 OTHER COMPREHENSIVE INCOME (LOSS) RELATING TO SUBSIDIARIES, NET OF TAX (3,269 ) (27 ) 34,016 COMPREHENSIVE INCOME $ 934,820 $ (150,248 ) $ 345,474 See accompanying notes to the Condensed Financial Information of Registrant SCHEDULE II ENSTAR GROUP LIMITED CONDENSED FINANCIAL INFORMATION OF REGISTRANT - CONTINUED Statements of Cash Flows - Parent Company Only For the Years Ended December 31, 2019 , 2018 and 2017 2019 2018 2017 (in thousands of U.S. dollars) OPERATING ACTIVITIES: Net cash flows provided by (used in) operating activities $ (128,462 ) $ (128,382 ) $ 97,898 INVESTING ACTIVITIES: Dividends and return of capital from subsidiaries 65,500 101,000 217,450 Contributions to subsidiaries (240,382 ) (660,339 ) (465,650 ) Net cash flows used in investing activities (174,882 ) (559,339 ) (248,200 ) FINANCING ACTIVITIES: Net proceeds from the issuance of preferred shares — 495,357 — Dividends on preferred shares (35,914 ) (12,133 ) — Repayment of loans (219,000 ) (898,633 ) (696,640 ) Receipt of loans 547,613 1,115,885 844,516 Net cash flows provided by financing activities 292,699 700,476 147,876 NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS (10,645 ) 12,755 (2,426 ) CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR 15,213 2,458 4,884 CASH AND CASH EQUIVALENTS, END OF YEAR $ 4,568 $ 15,213 $ 2,458 See accompanying notes to the Condensed Financial Information of Registrant Notes to the Condensed Financial Information of Registrant The Condensed Financial Information of Registrant should be read in conjunction with our consolidated financial statements and the accompanying notes thereto included in Part II - Item 8 of this Annual Report on Form 10-K. Our wholly owned and majority owned subsidiaries are recorded based upon our proportionate share of our subsidiaries' net assets (similar to presenting them on the equity method). Investing activities in the Condensed Statements of Cash Flows primarily represents the flow of funds to and from subsidiaries to provide cash on hand to fund acquisitions and significant new business. Net investment income relates to interest on loans to subsidiaries. For the years ended December 31, 2019 , 2018 , and 2017 , interest paid was $46.5 million , $25.1 million , and $17.6 million , respectively. During the years ended December 31, 2019 , 2018 , and 2017 , non-cash investing activities included $nil , $nil and $31.6 million , respectively, for dividends and return of capital from subsidiaries and $nil , $414.8 million and $148.1 million , respectively, for contributions to subsidiaries. In 2018, these transactions represented the contribution of the acquired outstanding shares and warrants of KaylaRe Holdings, Ltd to another subsidiary company. In 2017, these transactions were to settle intercompany balances, resulting in a net reduction in balances due from subsidiaries and an increase in investments in subsidiaries. As of December 31, 2019 , parental guarantees and capital support instruments supporting subsidiaries' insurance obligations were $1,031.5 million . In addition, as of December 31, 2019 there were $252.0 million of unsecured letters of credit for Funds at Lloyd's which have a parental guarantee. As of December 31, 2019 and 2018 , retained earnings were $2,887.9 million and $1,976.5 million , respectively, an increase of $911.4 million . This increase was primarily attributable to the net earnings of $902.2 million .

Schedule III - Supplementary In

Schedule III - Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2019
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
Schedule III - Supplementary Insurance Information	SCHEDULE III ENSTAR GROUP LIMITED SUPPLEMENTARY INSURANCE INFORMATION (Expressed in thousands of U.S. Dollars) As of December 31, Year ended December 31, Deferred Acquisition Costs Reserves for Losses and Loss Adjustment Expenses Unearned Premiums Policy Benefits for Life and Annuity Contracts Net Premiums Earned Net Investment Income Losses and Loss Expenses and Policy Benefits Amortization of Deferred Acquisition Costs Other Operating Expenses Net Premiums Written 2019 Non-life run-off $ 41,753 $ 8,295,361 $ 129,715 $ — $ 168,496 $ 275,236 $ 51,625 $ 73,642 $ 270,445 $ (25,338 ) Atrium 22,184 231,672 80,863 — 164,059 7,049 77,276 56,956 28,277 172,356 StarStone 89,180 1,879,128 518,199 — 801,926 47,401 727,636 174,711 128,419 735,429 Other 388 23,077 17,998 — 20,380 (8,410 ) 16,129 642 45,945 18,512 Total $ 153,505 $ 10,429,238 $ 746,775 $ — $ 1,154,861 $ 321,276 $ 872,666 $ 305,951 $ 473,086 $ 900,959 2018 Non-life run-off $ 4,378 $ 7,540,662 $ 136,023 $ — $ 9,427 $ 226,287 $ (306,067 ) $ 4,006 $ 197,824 $ (9,217 ) Atrium 20,355 241,284 70,429 — 146,315 5,686 69,810 50,646 24,698 153,488 StarStone 96,004 1,608,697 619,164 — 714,959 35,973 673,383 135,452 156,726 805,562 Other 364 18,861 17,002 105,080 24,874 2,725 17,902 2,686 28,127 32,067 Total $ 121,101 $ 9,409,504 $ 842,618 $ 105,080 $ 895,575 $ 270,671 $ 455,028 $ 192,790 $ 407,375 $ 981,900 2017 Non-life run-off $ 655 $ 5,949,472 $ 14,275 $ — $ 14,162 $ 166,678 $ (190,674 ) $ 328 $ 233,827 $ 6,482 Atrium 18,385 240,873 64,877 — 134,747 4,218 69,419 47,688 29,586 134,214 StarStone 45,944 1,207,743 504,045 — 459,403 27,706 314,806 48,012 135,558 464,901 Other — — — 117,207 4,809 10,187 4,015 878 37,014 4,793 Total $ 64,984 $ 7,398,088 $ 583,197 $ 117,207 $ 613,121 $ 208,789 $ 197,566 $ 96,906 $ 435,985 $ 610,390

Schedule IV - Reinsurance

Schedule IV - Reinsurance	12 Months Ended
	Dec. 31, 2019
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]
Schedule IV - Reinsurance	SCHEDULE IV ENSTAR GROUP LIMITED REINSURANCE For the Years Ended December 31, 2019 , 2018 and 2017 (Expressed in thousands of U.S. Dollars) Gross Ceded to Other Companies Assumed from Other Companies Net Amount Percentage of Amount Assumed to Net 2019 Life insurance in force $ 725,293 $ (65,795 ) $ — $ 659,498 — % Premiums earned: Property and casualty 1,146,956 (267,174 ) 273,807 1,153,589 23.7 % Life and annuities 1,295 (23 ) — 1,272 — % Total premiums earned $ 1,148,251 $ (267,197 ) $ 273,807 $ 1,154,861 2018 Life insurance in force $ 855,366 $ (84,603 ) $ — $ 770,763 — % Premiums earned: Property and casualty 985,637 (330,110 ) 236,182 891,709 26.5 % Life and annuities 3,892 (26 ) — 3,866 — % Total premiums earned $ 989,529 $ (330,136 ) $ 236,182 $ 895,575 2017 Life insurance in force $ 979,291 $ (100,189 ) $ — $ 879,102 — % Premiums earned: Property and casualty 899,226 (433,075 ) 142,161 608,312 23.4 % Life and annuities 5,900 (1,091 ) — 4,809 — % Total premiums earned $ 905,126 $ (434,166 ) $ 142,161 $ 613,121

Schedule V - Valuation and Qual

Schedule V - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2019
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule V - Valuation and Qualifying Accounts	SCHEDULE V ENSTAR GROUP LIMITED VALUATION AND QUALIFYING ACCOUNTS For the Years Ended December 31, 2019 , 2018 and 2017 (Expressed in thousands of U.S. Dollars) Balance at Beginning of Year Charged to costs and expenses Charged to other Deductions (1) Balance at End of Year December 31, 2019 Reinsurance balances recoverable on paid and unpaid losses: Provisions for bad debt 156,732 — 111 (9,204 ) 147,639 Valuation allowance for deferred tax assets 212,113 2,792 — (97,515 ) 117,390 December 31, 2018 Reinsurance balances recoverable on paid and unpaid losses: Provisions for bad debt 165,213 — (1,837 ) (6,644 ) 156,732 Valuation allowance for deferred tax assets 188,300 (2,492 ) 18,000 8,305 212,113 December 31, 2017 Reinsurance balances recoverable on paid and unpaid losses: Provisions for bad debt 174,516 (1,536 ) (4,191 ) (3,576 ) 165,213 Valuation allowance for deferred tax assets 290,861 (16,694 ) — (85,867 ) 188,300 (1) Credited to the related asset account.

Schedule VI - Supplementary Inf

Schedule VI - Supplementary Information Concerning Property/Casualty Insurance Operations	12 Months Ended
	Dec. 31, 2019
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Abstract]
Schedule VI - Supplementary Information Concerning Property/Casualty Insurance Operations	SCHEDULE VI ENSTAR GROUP LIMITED SUPPLEMENTARY INFORMATION CONCERNING PROPERTY/CASUALTY INSURANCE OPERATIONS As of and for the years ended December 31, 2019 , 2018 and 2017 (Expressed in thousands of U.S. Dollars) As of December 31, Year ended December 31, Affiliation with Registrant Deferred Acquisition Costs Reserves for Unpaid Losses and Loss Adjustment Expenses Unearned Premiums Net Premiums Earned Net Investment Income Net Losses and Loss Expenses Incurred Net Paid Losses and Loss Expenses Amortization of Deferred Acquisition Costs Net Premiums Written Current Year Prior Year Consolidated Subsidiaries 2019 $ 153,505 $ 10,429,238 $ 746,775 $ 1,153,589 $ 320,780 $ 823,658 $ 48,917 $ (1,869,268 ) $ 305,774 $ 899,687 2018 121,101 9,409,504 842,618 891,708 269,093 689,782 (235,757 ) (1,384,545 ) 192,790 978,037 2017 64,984 7,398,088 583,197 608,312 198,602 437,853 (244,302 ) (945,194 ) 96,028 605,597

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Preparation	The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("U.S. GAAP").
Basis of Consolidation	The consolidated financial statements include our assets, liabilities and results of operations as of December 31, 2019 and 2018 and for the years ended December 31, 2019 , 2018 and 2017
Use of Estimates	The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Our actual results could differ materially from our estimates. Accounting policies that we believe are most dependent on assumptions and estimates are considered to be our critical accounting policies and are related to the determination of: • liability for losses and loss adjustment expenses ("LAE"); • reinsurance balances recoverable on paid and unpaid losses; • defendant asbestos and environmental liabilities and related insurance balances recoverable; • valuation allowances on reinsurance balances recoverable and deferred tax assets; • impairment charges, including other-than-temporary impairments on investment securities classified as available-for-sale, and impairments on goodwill, intangible assets and deferred charge assets; • gross and net premiums written and net premiums earned; • fair value measurements of investments; • fair value estimates associated with accounting for acquisitions; • fair value estimates associated with loss portfolio transfer reinsurance agreements for which we have elected the fair value option; and • redeemable noncontrolling interests.
Premiums	Non-Life Non-life premiums written are earned on a pro-rata basis over the period the coverage is provided. Reinsurance premiums are recorded at the inception of the policy, are based upon contractual terms and, for certain business, are estimated based on underlying contracts or from information provided by insureds and/or brokers. Changes in reinsurance premium estimates are expected and may result in adjustments in future periods. Any subsequent differences arising on such estimates are recorded as premiums written in the period in which they are determined. Certain non-life contracts are retrospectively rated and provide for a final adjustment to the premium based on the final settlement of all losses. Premiums on such contracts are adjusted based upon contractual terms, and management judgme nt is involved with respect to the estimate of the amount of losses that we expect to incur. Additional premiums are recognized at the time loss thresholds specified in the contract are exceeded and are earned over the coverage period, or are earned immediately if the period of risk coverage has passed. Premiums receivable Premiums receivable represent amounts currently due and amounts not yet due on insurance and reinsurance policies. Premiums for insurance policies and loss portfolio transfer reinsurance agreements are generally due at inception. Premiums for other reinsurance policies generally become due over the period of coverage based on the policy terms. We monitor the credit risk associated with premiums receivable, taking into consideration the impact of our contractual right to offset loss obligations or unearned premiums against premiums receivable. Amounts deemed uncollectible are charged to net earnings based on an expected loss approach. Changes in the estimates of premiums written will result in an adjustment to premiums receivable in the period they are determined. Unearned premiums and prepaid reinsurance premiums Unearned premiums represent the portion of premiums written that relate to the unexpired terms of policies in force. Premiums ceded are similarly pro-rated over the period the coverage is provided with the unearned portion being deferred as prepaid reinsurance premiums.
Acquisition Costs	Acquisition costs, consisting principally of commissions and brokerage expenses and certain premium taxes and fees incurred at the time a contract or policy is issued and that vary with and are directly related to the successful efforts of acquiring new insurance contracts or renewing existing insurance contracts, are deferred and amortized over the period in which the related premiums are earned. Deferred acquisition costs are limited to their estimated realizable value by line of business based on the related unearned premiums, anticipated claims and claim expenses and anticipated investment income. A premium deficiency occurs if the sum of anticipated losses and loss adjustment expenses exceed unearned premiums, deferred acquisition costs and anticipated investment income. A premium deficiency is initially recognized by charging any deferred acquisition costs to expense to the extent required in order to eliminate the deficiency. If the premium deficiency exceeds the deferred acquisition costs then a liability is accrued for the excess deficiency.
Losses and LAE	Non-life Run-off The liability for losses and LAE in the Non-life Run-off segment includes an amount determined from reported claims and an amount, based on historical loss experience and industry statistics, for losses incurred but not reported ("IBNR") determined using a variety of actuarial methods. These estimates are continually reviewed and are necessarily subject to the impact of future changes in factors such as claim severity and frequency, changes in economic conditions including the impact of inflation, legal and judicial developments, and medical cost trends. Our estimates, at inception and on an ongoing basis, do not include an estimate for potential future commutations and policy buybacks. Commutations and policy buybacks are often unique, and each commutation or policy buyback is separately negotiated. Therefore, the successful execution of one commutation or policy buyback does not necessarily impact the likelihood of other commutations or policy buybacks occurring in the future. We therefore exclude the impact of potential future commutations and policy buybacks in determining the liability for losses and LAE. While we believe that the liability for losses and LAE is adequate, the ultimate amount may be in excess of, or less than, the amounts provided. Adjustments will be reflected as part of the net increase or reduction in losses and LAE liabilities in the periods in which they become known. Premium and commission adjustments may be triggered by incurred losses, and any amounts are recorded in the same period that the related incurred loss is recognized. Commutations of acquired companies’ exposures have the effect of accelerating the payout of claims compared to the probability-weighted ranges of actuarially projected cash flows that we applied when estimating the fair values of assets and liabilities at the time of acquisition. Commutations and policy buybacks provide an opportunity for us to exit exposures to certain policies and insureds generally at a discount to our estimate of the ultimate liability and provide us with the ability to eliminate exposure to further losses. Commutations and policy buybacks can be beneficial to us as they legally extinguish liabilities in full, reduce the potential for future adverse loss development, and reduce future claims handling costs. Any material acceleration of payout together with the impact of any material loss reserve savings in any period will also accelerate the amortization of fair value adjustments and deferred charge assets in that period. Commutations are only executed directly with insureds or reinsureds and any g ains realized or losses incurred on the settlement of losses and LAE liabilities through commutations or policy buybacks are recognized upon the execution of a commutation or policy buyback with the insured or reinsured. Our estimate of the liability for losses and LAE does not consider historical commutations and policy buybacks and also does not include an estimate for potential future commutations and policy buybacks. Our insurance and reinsurance subsidiaries also establish provisions for LAE relating to run-off costs for the estimated duration of the run-off, which are included in the liability for losses and LAE. These provisions are assessed at each reporting date, and provisions relating to future periods are adjusted to reflect any changes in estimates of the periodic run-off costs or the duration of the run-off, including the impact of any acceleration of the run-off period that may be caused by commutations. Provisions relating to the current period together with any adjustment to future run-off provisions are included in net incurred losses and LAE in the consolidated statements of earnings. Atrium and StarStone The reserves for losses and LAE in the Atrium and StarStone segments include reserves for unpaid reported losses and for IBNR loss reserves. The reserves for unpaid reported losses and loss expenses are established by management based on reports from brokers, ceding companies and insureds and represent the estimated ultimate cost of events or conditions that have been reported to or specifically identified by us. The reserve for IBNR losses is established by us based on actuarially determined estimates of ultimate losses and loss expenses. Inherent in the estimate of ultimate losses and loss expenses are expected trends in claim severity and frequency and other factors which may vary significantly as claims are settled. Accordingly, ultimate losses and loss expenses may differ from the amounts recorded in the consolidated financial statements. These estimates are reviewed regularly and, as experience develops and new information becomes known, the reserves are adjusted as necessary. Such adjustments, if any, will be recorded in earnings in the period in which they become known. Prior period development arises from changes to loss estimates recognized in the current year that relate to loss reserves established in prev ious calendar years. Components of Net Incurred Losses and LAE Included within the total net incurred losses and LAE on our consolidated statement of earnings are the following items: • Net losses paid: paid losses and LAE, net of related reinsurance recoveries. • Net change in case and LAE reserves: the change in case reserves and associated LAE, net of related reinsurance recoveries. • Net change in IBNR reserves: the change in IBNR reserves, net of related reinsurance recoveries. • Increase (reduction) in estimates of net ultimate losses: the total of net losses paid, net change in case and LAE reserves and the net change in IBNR. This includes the net impact of commutations and policy buybacks on the liability for losses and LAE reserves and reinsurance recoveries. • Increase (reduction) in provisions for unallocated LAE: the net change in our provision for unallocated LAE. • Amortization of deferred charge assets: the amortization of the deferred charge assets associated with assumed retroactive reinsurance contracts, where the estimated ultimate losses assumed at the inception of the contracts is greater than the premium consideration received. • Amortization of fair value adjustments: the amortization of the fair value adjustments associated with acquired companies, where the assumed losses and LAE reserves and the acquired reinsurance recoveries are fair valued on acquisition. • Changes in fair value - fair value option: the changes in the fair value for reinsurance agreements where we have elected the fair value option. The change in fair value component includes the changes in the discounted cash flows and risk margin. The underlying net losses paid, net change in case and LAE reserves and the net change in IBNR reserves relating to these reinsurance agreements for which we have elected the fair value option are included within the appropriate line items described above. • Net incurred losses and LAE: the total of increase (reduction) in estimates of net ultimate losses, increase (reduction) in provisions for unallocated LAE, amortization of deferred charge assets, amortization of fair value adjustments and changes in fair value - fair value option.
Defendant Asbestos and Environmental Liabilities	We acquired DCo on December 30, 2016, and Morse TEC on October 30, 2019, as described in Note 3 - "Acquisitions" . DCo and Morse TEC hold liabilities associated with personal injury asbestos claims and environmental claims arising from their legacy manufacturing operations. DCo and Morse TEC continue to process asbestos personal injury claims. Defendant asbestos and environmental liabilities on our consolidated balance sheets include amounts for indemnity and defense costs for pending and future claims, determined using standard actuarial techniques for asbestos-related exposures. Defendant asbestos and environmental liabilities also include amounts for environmental liabilities associated with DCo's and Morse TEC's properties.
Reinsurance Balances Recoverable, Funds Held, and Retroactive Reinsurance	Amounts billed to, and due from, reinsurers resulting from paid movements in the underlying business are calculated in accordance with the terms of the individual reinsurance contracts. Similarly, reinsurance balances recoverable on paid and unpaid losses related to our case reserves are calculated by applying the terms of any applicable reinsurance coverage to movements in the underlying case reserves. Our estimate of reinsurance balances recoverable on paid and unpaid losses related to IBNR reserves is recognized on a basis consistent with the underlying IBNR reserves. Our reinsurance balances recoverable on paid and unpaid losses are presented net of a provision for uncollectible amounts, reflecting the amount deemed not collectible due to credit quality, collection problems due to the location of the reinsurer, contractual disputes with reinsurers over individual contentious claims, contract language or coverage issues. Retroactive reinsurance policies provide indemnification for losses and LAE with respect to past loss events. In our Non-life Run-off segment we use the balance sheet accounting approach for assumed loss portfolio transfers, whereby at the inception of the contract there are no premiums or losses recorded in earnings. Deferred Charge Assets If, at the inception of a Non-life Run-off retroactive reinsurance contract, the estimated undiscounted ultimate losses payable are in excess of the premiums received, a deferred charge asset is recorded for the excess. The premium consideration that we charge the ceding companies may be lower than the undiscounted estimated ultimate losses payable due to the time value of money. After receiving the premium consideration in full from our cedents at the inception of the contract, we invest the premium received over an extended period of time, thereby generating investment income. We expect to generate profits from these retroactive reinsurance policies when taking into account the premium received and expected investment income, less contractual obligations and expenses. Deferred charge assets, recorded in other assets, are amortized over the estimated claim payment period of the related contract with the periodic amortization reflected in earnings as a component of losses and LAE. The amortization of deferred charge assets is adjusted at each reporting period to reflect new estimates of the amount and timing of remaining loss ad LAE payments. Changes in the estimated amount and the timing of payments of unpaid losses may have an effect on the unamortized deferred charge assets and the amount of periodic amortization. When liabilities for losses and LAE are extinguished through commutations and policy buybacks, they are removed from our estimates for the remaining loss and LAE payments, and this will generally result in an acceleration of the amortization of the deferred charge assets. Deferred charge assets are assessed at each reporting period for impairment and if the asset is determined to be impaired, then it is written down in the period in which the determination is made. Fair Value Option In our Non-life Run-off segment, we have elected to apply the fair value option for certain loss portfolio transfer reinsurance transactions. This is an irrevocable election that applies to all balances under the insurance contract, including funds held assets, reinsurance balances recoverable on paid and unpaid losses, and the liability for losses and loss adjustment expenses. We use an internal model to calculate the fair value of the liability for losses and loss adjustment expenses and the reinsurance balances recoverable on paid and unpaid losses. Note 12 - "Fair Value Measurements" describes the internal model, including the observable and unobservable inputs used in the model.
Insurance Balances Recoverable	Amounts billed to and due from insurers providing coverage for our defendant asbestos liabilities are calculated in accordance with the terms of the individual insurance contracts. The insurance balances recoverable related to our defendant asbestos liabilities are presented net of a provision for uncollectible amounts, reflecting the amount deemed not collectible primarily due to credit quality and contractual disputes with insurers over coverage issues.
Investments	Short-term investments and fixed maturity investments Short-term investments comprise investments with a maturity greater than three months up to one year from the date of purchase. Fixed maturities comprise investments with a maturity of greater than one year from the date of purchase. Short-term and fixed maturity investments classified as trading are carried at fair value, with realized and unrealized holding gains and losses included in net earnings and reported as net realized and unrealized gains and losses. Short-term and fixed maturity investments classified as available-for-sale are carried at fair value, with unrealized gains and losses excluded from net earnings and reported as a separate component of accumulated other comprehensive income (loss) ("AOCI") . Realized gains and losses on sales of investments classified as available-for-sale are recognized in the consolidated statements of earnings. The costs of short-term and fixed maturity investments are adjusted for amortization of premiums and accretion of discounts, recognized using the effective yield method and included in net investment income. For mortgage-backed and asset-backed investments, and any other holdings for which there is a prepayment risk, prepayment assumptions are evaluated and reviewed on a regular basis. Investment purchases and sales are recorded on a trade-date basis. Realized gains and losses on the sale of investments are based upon specific identification of the cost of investments. Other-Than-Temporary Impairments Fixed maturity investments classified as available-for-sale are reviewed quarterly to determine if they have sustained an impairment of value that is, based on our judgment, considered to be other than temporary. The process includes reviewing each fixed maturity investment whose fair value is below amortized cost and: (1) determining if we have the intent to sell the fixed maturity investment; (2) determining if it is more likely than not that we will be required to sell the fixed maturity investment before its anticipated recovery; and (3) assessing whether a credit loss exists, that is, whether we expect that the present value of the cash flows expected to be collected from the fixed maturity investment is less than the amortized cost basis of the investment. In assessing whether it is more likely than not that we will be required to sell a fixed maturity investment before its anticipated recovery, we consider various factors including our future cash flow requirements, legal and regulatory requirements, the level of our cash, cash equivalents, short-term investments and fixed maturity investments available-for-sale in an unrealized gain position, and other relevant factors. In evaluating credit losses, we consider a variety of factors in the assessment of a fixed maturity investment including: (1) the time period during which there has been a significant decline below cost; (2) the extent of the decline below cost and par; (3) the potential for the investment to recover in value; (4) an analysis of the financial condition of the issuer; (5) the rating of the issuer; and (6) failure of the issuer of the investment to make scheduled interest or principal payments. If we conclude that an investment is other-than-temporarily impaired ("OTTI"), then the difference between the fair value and the amortized cost of the investment is presented as an OTTI charge in the consolidated statements of earnings, with an offset for any non-credit related loss component of the OTTI charge to be recognized in other comprehensive income. Accordingly, only the credit loss component of the OTTI amount would have an impact on our earnings. Equities We hold investments in publicly traded equities and exchange-traded funds as well as in privately held equities. Our equity investments are carried at fair value with realized and unrealized holding gains and losses included in net earnings and reported as net realized and unrealized gains and losses. Other investments, at fair value Other investments include investments in limited partnerships and limited liability companies (collectively "private equities") and fixed income funds, hedge funds, equity funds, private credit funds and collateralized loan obligation ("CLO") equity funds that carry their investments at fair value, as well as direct investments in CLO equities. These other investments are stated at fair value, which ordinarily will be the most recently reported net asset value as advised by the fund manager or administrator. Many of our fund investments publish net asset values on a daily basis and provide daily liquidity; others report on a monthly basis. Private equities typically report quarterly. The change in fair value is included in net realized and unrealized gains and losses on investments and recognized in net earnings. Equity method investments Investments in which the Company has significant influence over the operating and financial policies of the investee are classified as equity method investments and are accounted for using the equity method of accounting. In applying the equity method of accounting, investments are initially recorded at cost and are subsequently adjusted based on the Company's proportionate share of net income or loss of the investee, net of any distributions received from the investee. Adjustments are based on the most recently available financial information from the investee. Changes in the carrying value of such investments are recorded in our consolidated statements of earnings as earnings (losses) from equity method investments. Any decline in the value of our equity method investments considered by management to be other-than-temporary is reflected in our consolidated statements of earnings in the period in which it is determined.
Cash and cash equivalents	Cash equivalents includes money market funds, fixed interest deposits and all highly liquid debt instruments purchased with an original maturity of three months or less.
Fees and Commission Income	Fees and commission income primarily includes profit commissions earned from managed Lloyd's syndicates as well as fees earned under fronting and consulting arrangements with third-party clients, which are recorded on an accrual basis.
Foreign Exchange	Our reporting currency is the U.S. dollar. Assets and liabilities of entities whose functional currency is not the U.S. dollar are translated at period end exchange rates. Revenues and expenses of such foreign entities are translated at average exchange rates during the year. The effect of the currency translation adjustments for these foreign entities is included in accumulated other comprehensive income (loss). Other foreign currency assets and liabilities that are considered monetary items are translated at exchange rates in effect at the balance sheet date. Foreign currency revenues and expenses are translated either at transaction date exchange rates or using an appropriately weighted average exchange rate for the reporting period. These exchange gains and losses are recognized in net earnings.
Share-based Compensation	We primarily use three types of share-based compensation arrangements: (i) restricted shares, restricted share units and performance share units, (ii) cash-settled stock appreciation rights ("SARs") and (iii) shares issued under our employee share purchase plans. With the exception of SARs and the incentive plan awards issued to certain employees of Atrium and StarStone, our share-based compensation awards qualify for equity classification. The fair value of the compensation cost is measured at the grant date and is expensed over the service period of the award. The SARs, the Atrium and StarStone incentive plan awards are classified as liability awards. Liability classified awards are recorded at fair value within other liabilities in the consolidated balance sheet with changes in fair value relating to the vested portion of the award recorded within general and administrative expenses in the consolidated statements of earnings.
Derivative Instruments	We utilize derivative instruments in our foreign currency and interest rate risk management strategies and recognize all derivatives as either assets or liabilities in the consolidated balance sheets and carry them at the fair value of the specific instrument utilized. Changes in the fair value as well as realized gains or losses on derivative instruments are recognized in net earnings if they are not designated as qualifying hedging instruments or if the criteria for establishing a perfectly effective designated hedging relationship for our net investment hedges has not been met. However, if a designated net investment hedge is deemed to be perfectly effective, then we recognize the changes in the fair value of the underlying hedging instrument in accumulated other comprehensive income (loss) until the application of hedge accounting is discontinued. Any cumulative gains or losses arising on designated net investment hedges are deferred in accumulated other comprehensive income (loss) until the cumulative translation adjustment ("CTA") from the underlying hedged net investment is recognized in net earnings due to a disposal, deconsolidation or substantial liquidation. Certain of our funds held arrangements also contain embedded derivatives as described above, which are carried at fair value. In addition, we also hold equity call options carried at fair value, as part of our investment strategy.
Income Taxes	Certain of our subsidiaries and branches operate in jurisdictions where they are subject to taxation. Current and deferred tax expense or benefit is allocated to net earnings (loss), or, in certain cases, to discontinued operations or other comprehensive income (loss). Current tax is recognized and measured upon enacted tax laws and rates applicable in the relevant jurisdiction in the period in which the income tax becomes accruable or realizable. Deferred taxes are provided for temporary differences between the carrying amount of assets and liabilities used in the financial statements and the tax basis used in the various jurisdictional tax returns. When our assessment indicates that all or some portion of deferred tax assets will not be realized, a valuation allowance is recorded against the deferred tax assets to reduce the assets to the amount more likely than not to be realized. We recognize the benefit relating to tax positions only where the position is more likely than not to be sustained assuming examination by tax authorities. A recognized tax benefit is measured as the largest amount that is greater than 50 percent likely of being realized upon settlement. A liability or other adjustment is recognized for any tax benefit (along with any interest and penalty, if applicable) claimed in a tax return in excess of the amount allowed to be recognized in the financial statements under U.S. GAAP. Any changes in amounts recognized are recorded in the period in which they are determined.
Earnings Per Share	Basic earnings per share is based on the weighted average number of ordinary shares outstanding and excludes potentially dilutive securities such as restricted shares, restricted share units, warrants, options and convertible securities. Diluted earnings per share is based on the weighted average number of ordinary and ordinary share equivalents outstanding calculated using the treasury stock method for all potentially dilutive securities. When the effect of dilutive securities would be anti-dilutive, these securities are excluded from the calculation of diluted earnings per share.
Acquisitions	The acquisition method is used to account for all business acquisitions. This method requires that we record the acquired assets and liabilities at their estimated fair value. The fair values of each of the acquired reinsurance assets and liabilities are derived from probability-weighted ranges of the associated projected cash flows, based on actuarially prepared information and management’s run-off strategy. Our run-off strategy, as well as that of other run-off market participants, is expected to be different from the seller's as generally sellers are not specialized in running off insurance and reinsurance liabilities whereas we and other market participants do specialize in such run-offs. The key assumptions used by us and, we believe, by other run-off market participants in the valuation of acquired companies are (i) the projected payout, timing and amount of claims liabilities; (ii) the related projected timing and amount of reinsurance collections; (iii) an appropriate discount rate, which is applied to determine the present value of the future cash flows; (iv) the estimated unallocated LAE to be incurred over the life of the run-off; (v) the impact of any accelerated run-off strategy; and (vi) an appropriate risk margin.
Acquisitions, Fair Value Adjustment	The difference between the nominal carrying values of the acquired reinsurance liabilities and assets as of the acquisition date and their fair value is recorded as a fair value adjustment ("FVA") on the consolidated balance sheet. The FVA is amortized over the estimated payout period of the acquired outstanding losses and LAE and reinsurance balances recoverable. To the extent the actual payout experience after the acquisition is materially faster or slower than anticipated at the time of the acquisition as a result of (i) our active claims management strategies, which include commutations and policy buybacks , (ii) an adjustment to the estimated ultimate loss reserves, (iii) changes in bad debt provisions, or (iv) changes in estimates of future run-off costs following accelerated payouts, then the amortization of the FVA is adjusted to reflect such changes.
Goodwill	The difference between the fair value of net assets acquired and the purchase price is recorded as goodwill and included as an asset on the consolidated balance sheet or as a gain from bargain purchase in the consolidated statements of earnings. Goodwill is established initially upon acquisition and assessed at least annually for impairment. If the goodwill asset is determined to be impaired it is written down in the period in which the determination is made.
Intangible Assets	Intangible assets represent both the definite-lived and indefinite-lived intangible assets arising from the acquisitions of Atrium and StarStone. Definite-lived intangible assets are amortized over their useful lives with the amortization expense being recognized in the consolidated statements of earnings. Indefinite-lived intangible assets are not subject to amortization. The carrying values of intangible assets are reviewed for indicators of impairment at least annually. Impairment is recognized if the carrying values of the definite-lived intangible assets are not recoverable from their undiscounted cash flows and is measured as the amount by which the carrying value exceeds the fair value. Similarly, for indefinite-lived intangible assets, i f the carrying value of the asset exceeds its fair value, then an impairment loss is recognized in an amount equal to the excess.
Redeemable Noncontrolling Interest	In connection with the acquisitions of Arden, Atrium and StarStone, certain subsidiaries issued shares to noncontrolling interests. These shares provide certain redemption rights to the holders, which may be settled in our own shares or cash or a combination of cash and shares, at our option. Redeemable noncontrolling interests with redemption features that are not solely within our control are classified within temporary equity in the consolidated balance sheets and carried at their redemption value, which is fair value. Change in the fair value is recognized through retained earnings as if the balance sheet date were also the redemption date.
Internal-use Software	Direct internal and external costs to acquire or develop internal-use software have been capitalized. We only capitalize costs incurred after the preliminary project stage has been completed, and when management has authorized and committed to funding the project and it is probable that the project will be completed and the software will be used to perform the functions intended. Capitalized costs related to internal-use software are amortized on a straight-line basis over the estimated useful lives of the assets. These capitalized costs are also assessed for impairment when impairment indicators exist.
Held-for-sale Business and Discontinued Operations	We report a business as held-for-sale when certain criteria are met, which include (1) management has either approved the sale or is in the process of obtaining approval to sell the business and is committed to a formal plan to sell the business, (2) the business is available for immediate sale in its present condition, (3) the business is being actively marketed for sale at a price that is reasonable in relation to its current fair value, and (4) the sale is anticipated to occur within the next 12 months, among other specified criteria. A business classified as held for sale is recorded at the lower of its carrying amount or estimated fair value less costs to sell. If the carrying amount of the business exceeds its estimated fair value, a loss is recognized. Assets and liabilities related to the businesses classified as held-for-sale are separately reported in our Consolidated Balance Sheets beginning in the period in which the business is classified as held-for-sale. Refer to Note 5 - "Divestitures, Held-for-Sale Businesses and Discontinued Operations" for further information regarding our held-for-sale business. Disposals that represent strategic shifts that have or will have a major effect on our operations and financial results are reported as discontinued operations.
New Accounting Standards Adopted and Recently Issued Accounting Pronouncements Not Yet Adopted	New Accounting Standards Adopted in 2019 Accounting Standards Update ("ASU") 2019-07 - Codification Updates to SEC Sections In July 2019, the Financial Accounting Standards Board (the "FASB") issued ASU 2019-07 in response to the Securities and Exchange Commission's ("SEC's") disclosure update and simplification initiative. The ASU clarifies or improves the disclosure and presentation requirements of a variety of Codification Topics by aligning them with the SEC’s regulations, thereby eliminating redundancies and making the Codification easier to apply. The adoption of the disclosure and presentation amendments included in this ASU and which are to be applied prospectively, did not have a material impact on our consolidated financial statements and disclosures . ASU 2018-13, Changes to the Disclosure Requirements for Fair Value Measurements In August 2018, the FASB issued ASU 2018-13, which amended the fair value measurement guidance in Accounting Standards Codification ("ASC") 820 - Fair Value Measurement , by removing and modifying certain existing disclosure requirements, while also adding some new disclosure requirements. We adopted the new standard as of December 31, 2019 however these new or modified disclosures did not have a material impact on the fair value measurement disclosures included in our consolidated financial statements. ASU 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income In February 2018, the FASB issued ASU 2018-02, which gives entities the option to reclassify to retained earnings tax effects related to items in accumulated other comprehensive income (“AOCI”) that are deemed stranded in AOCI as a result of the Tax Cuts and Jobs Act (the "Tax Act") enacted in the United States at the end of 2017. The amendments in this guidance eliminate the stranded tax effects resulting from the Tax Act and will improve the usefulness of information reported to financial statement users. We adopted the new standard on January 1, 2019, and that adoption did not have a material impact on our consolidated financial statements and related disclosures. ASUs 2016-02, 2018-10, 2018-11 and 2019-01, Leases In February 2016, the FASB issued ASU 2016-02, which is codified in ASC 842 - Leases , amending the guidance on the classification, measurement and disclosure of leases for both lessors and lessees. The ASU requires lessees to recognize a right-of-use asset and an offsetting lease liability on the balance sheet and to disclose qualitative and quantitative information about leasing arrangements. Subsequently, in July 2018, the FASB issued ASU 2018-10, which clarifies how to apply certain aspects of ASC 842. The amendments in the ASU address a number of issues in the new leases guidance, including (1) the rate implicit in the lease, (2) impairment of the net investment in the lease, (3) lessee reassessment of lease classification, (4) lessor reassessment of lease term and purchase options, (5) variable payments that depend on an index or rate, and (6) certain transition adjustments. In July 2018, the FASB also issued ASU 2018-11, which adds a transition option for all entities and a practical expedient only for lessors, to ASU 2016-02. The transition option, which we elected on adoption of the guidance, allows entities not to apply the new leases standard in the comparative periods they present in their financial statements in the year of adoption. Under the transition option, entities can instead opt to continue to apply the legacy guidance in ASC 840 - Leases , including its disclosure requirements, in the comparative periods presented in the year they adopt the new leases standard. This means that entities that elect this option will only provide annual disclosures for the comparative periods because ASC 840 does not require interim disclosures. Entities that elect this transition option are still required to adopt the new leases standard using the modified retrospective transition method, but they will recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption rather than in the earliest period presented. The practical expedient provides lessors with an option to not separate the non-lease components from the associated lease components when certain criteria are met and requires them to account for the combined component in accordance with the revenue recognition standard in ASC 606 if the associated non-lease components are the predominant components. In addition, in March 2019, the FASB issued ASU 2019-01 to clarify that in the year of initial adoption of ASC 842, entities are not subject to the transition disclosure requirements in ASC 250-10-50-3 related to the effect of an accounting change on certain interim period financial information. Prior to this clarification, the transition guidance in ASC 842 only excluded the annual disclosures required in ASC 250-10-50-1(b)(2). We adopted ASU 2016-02 and the related amendments on January 1, 2019 using the modified retrospective transition method as required by the standard and recognized a right-of-use asset and an associated lease liability of $51.6 million on our consolidated balance sheet, relating primarily to office space and facilities that we have leased to conduct our business operations. Refer to Note 23 - "Commitments and Contingencies" for further details. Recently Issued Accounting Pronouncements Not Yet Adopted ASU 2020-01 - Clarifying the Interactions between ASC 321, ASC 323 and ASC 815 In January 2020, the FASB issued ASU 2020-01 to clarify the interaction of the accounting for equity securities under ASC 321 and investments accounted for under the equity method of accounting in ASC 323 and the accounting for certain forward contracts and purchased options accounted for under ASC 815. With respect to the interactions between ASC 321 and ASC 323, the amendments clarify that an entity should consider observable transactions that require it to either apply or discontinue the equity method of accounting when applying the measurement alternative in ASC 321, immediately before applying or upon discontinuing the equity method of accounting . With respect to forward contracts or purchased options to purchase securities, the amendments clarify that when applying the guidance in ASC 815-10-15-141(a), an entity should not consider whether upon the settlement of the forward contract or exercise of the purchased option, individually or with existing investments, the underlying securities would be accounted for under the equity method in ASC 323 or the fair value option in accordance with ASC 825. The ASU is effective for interim and annual reporting periods beginning after December 15, 2020, although early adoption is permitted, including adoption in any interim period. We do not expect the adoption of this standard to have a material impact on our consolidated financial statements and disclosures. ASU 2019-12 - Simplifying the Accounting for Income Taxes In December 2019, the FASB issued ASU 2019-12 which removes certain exceptions for (1) recognizing deferred taxes for investments, (2) performing intraperiod tax allocation, and (3) calculating income taxes in interim periods. The ASU also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating income taxes to a legal entity that is not subject to income taxes. The ASU is effective for interim and annual reporting periods beginning after December 15, 2020, although early adoption is permitted, including adoption in any interim period. We are currently assessing the impact of adopting this guidance however we do not expect that the adoption will have a material impact on our consolidated financial statements and disclosures. ASUs 2016-13, 2018-19, 2019-04, 2019-05, 2019-10 and 2019-11, Financial Instruments - Credit Losses - Measurement of Credit Losses on Financial Instruments In June 2016, the FASB issued ASU 2016-13, which is codified in ASC 326, amending the guidance on the impairment of financial instruments and significantly changing how entities measure credit losses for most financial assets and certain other financial instruments including reinsurance balances recoverable on paid and unpaid losses that are not measured at fair value through net income. The ASU will replace the existing “incurred loss” approach, with an “expected loss” model for instruments measured at amortized cost and require entities to record allowances for available-for-sale ("AFS") debt securities rather than reduce the carrying amount under the existing OTTI model. The ASU also simplifies the accounting model for purchased credit-impaired debt securities and loans. In November 2018, the FASB then issued ASU 2018-19 covering targeted improvements to ASU 2016-13, which clarifies that receivables arising from operating leases are not within the scope of ASC 326-20 and that instead, the impairment of such receivables should be accounted for in accordance with ASC 842 - Leases . In April 2019, the FASB also issued ASU 2019-04, which amends (1) ASU 2016-13 as codified in ASC 326, (2) ASU 2017-12 on hedging activities as codified in ASC 815, and (3) ASU 2016-01 on recognizing and measuring financial instruments as codified in ASC 825-10. Specifically with respect to ASC 326, the amendments in ASU 2019-04 clarify the scope of the credit losses standard and address issues related to accrued interest receivable balances, recoveries, variable interest rates and prepayments. In May 2019, the FASB then issued ASU 2019-05, which amends ASU 2016-13 to provide entities with an option to irrevocably elect the fair value option for certain financial assets previously measured on an amortized cost basis. Entities that avail themselves of this transition relief will have the option to irrevocably elect the fair value option in ASC 825-10 on an instrument-by-instrument basis for eligible instruments, upon the adoption of ASC 326. The fair value option election, however, does not apply to held-to-maturity debt securities. An entity that elects the fair value option should subsequently apply the guidance in ASC 820-10 and ASC 825-10 to the eligible instruments for which it has elected the fair value option. In November 2019, the FASB also issued ASU 2019-10 deferring the effective dates for ASU 2016-13; ASU 2017-12 and ASU 2016-02 for non-public business entities. With respect to ASU 2016-13, this deferral was also extended to entities that meet the smaller reporting company eligibility criteria. Finally, in November 2019, the FASB issued ASU 2019-11 which clarified the following specific issues related to the amendments in ASU 2016-13: (1) the treatment for expected recoveries for purchased financial assets with credit deterioration or PCD assets, (2) application of the transition relief provided for troubled debt restructuring ("TDRs"), (3) disclosures related to accrued interest receivables, and (4) the application of the practical expedient related to financial assets secured by collateral maintenance provisions. We adopted ASU 2016-13 and all the related amendments on January 1, 2020 using the modified retrospective approach and recorded a cumulative effect adjustment of approximately $1.6 million to increase opening retained earnings with respect to our financial instruments carried at amortized cost, which primarily relate to our reinsurance balances recoverable. As disclosed in Note 8 - Reinsurance Balances Recoverable on Paids and Unpaid Losses, we already carry significant specific provisions for bad debts amounting to $147.6 million on our reinsurance balances recoverable, relating primarily to our Non-life Run-off segment. Therefore, the adoption of ASU 2016-13 and the related amendments did not have a material quantitative impact on the overall credit allowance established against our reinsurance balances recoverable. As a result of adopting ASU 2016-13 and the related amendments, we also recorded a credit allowance of approximately $3.1 million related to our AFS debt securities whose fair values were less than their amortized cost basis. In addition to the estimated quantitative impact of adopting ASU 2016-13 and the related amendments, as illustrated above, the guidance will also require us to amend and in certain cases, significantly enhance the qualitative disclosures included in our consolidated financial statements around the following specific items: (1) the credit risk inherent within our portfolios of financial assets and how we monitor credit quality, (2) how we determine the estimation of expected credit losses, (3) changes in the estimate of expected credit losses that have occurred during each reporting period, and (4) providing a roll-forward analysis of our allowance for credit losses.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2019
Morse TEC
Business Acquisition [Line Items]
Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed as of Date of Acquisition	The following table summarizes the fair values of the assets acquired and liabilities assumed in the Morse TEC transaction at the acquisition date, which have all been allocated to the Non-life Run-off segment. ASSETS Cash and cash equivalents $ 171,412 Deferred tax assets 140,000 Other assets - insurance balances receivable 371,116 TOTAL ASSETS 682,528 LIABILITIES Defendant asbestos and environmental liabilities 662,507 Other liabilities 20,021 TOTAL LIABILITIES $ 682,528 NET ASSETS ACQUIRED AT FAIR VALUE —
Pro Forma Condensed Combined Statement of Earnings	The table below summarizes the results of the Morse TEC operations, which are included in our consolidated statement of earnings from the acquisition date to December 31, 2019: Net investment income $ 488 General and administrative expenses (1,459 ) Other expenses (1,512 ) Net loss $ (2,483 ) The following unaudited pro forma condensed combined statement of earnings for the years ended December 31, 2019 and 2018 combines our historical consolidated statements of earnings with those of Morse TEC , giving effect to the business combination transaction as if it had occurred on January 1, 2019 and 2018, respectively. The unaudited pro forma financial information presented below is for informational purposes only and is not necessarily indicative of the results of operations that would have been achieved if the acquisition of Morse TEC had taken place at the beginning of each period presented, nor is it indicative of future results. 2019 Enstar Group Limited Morse TEC Pro Forma Adjustments Enstar Group Limited - Pro forma Total income $ 2,629,021 $ 76,480 $ (488 ) $ 2,705,013 Total expenses (1,700,802 ) (8,918 ) 1,459 (1,708,261 ) Total noncontrolling interest 9,870 — — 9,870 Net earnings (loss) attributable to Enstar Group Limited $ 938,089 $ 67,562 $ 971 $ 1,006,622 2018 Enstar Group Limited Morse TEC Enstar Group Limited - Pro forma Total income $ 865,682 $ 42,766 $ 908,448 Total expenses (1,077,954 ) (30,187 ) (1,108,141 ) Total noncontrolling interest 62,051 — 62,051 Net earnings (loss) attributable to Enstar Group Limited $ (150,221 ) $ 12,579 $ (137,642 )
Summary of Pro Forma Adjustments to Pro Forma Condensed Statement of Earnings	The following table summarizes the pro-forma adjustments in the table above: Income (a) Total income for the period subsequent to the acquisition of Morse TEC already included within Enstar's full year results $ (488 ) Expenses (a) Total expenses for the period subsequent to the acquisition of Morse TEC already included within Enstar's full year results $ 1,459
Maiden Re
Business Acquisition [Line Items]
Purchase Price and Fair Value of Assets Acquired	The components of the consideration paid to acquire all of the outstanding shares of Maiden Re North America were as follows: Cash paid $ 286,375 Adjustment for the fair value of preexisting relationships 10,273 Total purchase price $ 296,648 Net assets acquired at fair value (excluding preexisting relationships) $ 296,648 Excess of purchase price over fair value of net assets acquired $ —
Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed as of Date of Acquisition	The following table summarizes the fair values of the assets acquired and liabilities assumed (excluding preexisting relationships and net of the intercompany cession assumed as part of the transaction) in the Maiden Re North America transaction at the acquisition date, which have all been allocated to the Non-life Run-off segment. ASSETS Fixed maturities, trading, at fair value $ 1,098,593 Short-term investments, trading, at fair value 3,508 Total investments 1,102,101 Cash and cash equivalents 12,035 Restricted cash and cash equivalents 26,871 Premiums receivable 138,378 Prepaid reinsurance premiums 3,257 Reinsurance balances recoverable 87,018 Other assets 96,669 TOTAL ASSETS $ 1,466,329 LIABILITIES Losses and LAE $ 1,027,367 Unearned premiums 85,696 Other liabilities 56,618 TOTAL LIABILITIES 1,169,681 NET ASSETS ACQUIRED AT FAIR VALUE $ 296,648
Pro Forma Condensed Combined Statement of Earnings	The table below summarizes the results of the Maiden Re North America operations, which are included in our consolidated statement of earnings from the acquisition date to December 31, 2018: Net investment income $ 675 Net unrealized gains 3,749 General and administrative expenses (435 ) Net earnings $ 3,989
KaylaRe
Business Acquisition [Line Items]
Purchase Price and Fair Value of Assets Acquired	The components of the consideration paid to acquire all of the outstanding shares and warrants of KaylaRe were as follows: Fair value of Enstar ordinary shares issued $ 414,750 Fair value of previously held equity method investment 336,137 Adjustment for the fair value of preexisting relationships 37,169 Total purchase price $ 788,056 Net assets acquired at fair value (excluding preexisting relationships) $ 746,320 Excess of purchase price over fair value of net assets acquired $ 41,736 Number of Enstar ordinary shares issued 2,007,017 Closing price of Enstar voting ordinary shares as of May 14, 2018 $ 206.65 Fair value of Enstar ordinary shares issued to shareholders of KaylaRe $ 414,750 Carrying value of previously held equity method investment prior to the close of the transaction $ 320,130 Price-to-book multiple 1.05 Fair value of previously held equity method investment prior to the close of the transaction $ 336,137 Gain recognized on remeasurement of previously held equity method investment to fair value $ 16,007
Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed as of Date of Acquisition	The following table summarizes the fair values of the assets acquired and liabilities assumed (excluding preexisting relationships) in the KaylaRe transaction at the acquisition date, which have all been allocated to the Non-life Run-off segment. ASSETS Fixed maturities, trading, at fair value $ 126,393 Other investments, at fair value 626,476 Total investments 752,869 Cash and cash equivalents 5,657 Premiums receivable 10,965 Deferred acquisition costs 275 Other assets 614 TOTAL ASSETS $ 770,380 LIABILITIES Losses and LAE $ 4,059 Unearned premiums 10,984 Insurance and reinsurance balances payable 13 Other liabilities 9,004 TOTAL LIABILITIES 24,060 NET ASSETS ACQUIRED AT FAIR VALUE $ 746,320 As a result of effectively settling all the contractual preexisting relationships with KaylaRe, the Company recognized a loss of $15.6 million , which was recorded in other income (loss) in the three and six months ended June 30, 2018, as summarized below: ASSETS Carrying value Fair value Loss on deemed settlement Funds held by reinsured companies $ 386,793 $ 386,793 $ — Deferred acquisition costs/Value of business acquired 33,549 40,268 6,719 TOTAL ASSETS 420,342 427,061 6,719 LIABILITIES Losses and LAE 339,747 333,205 (6,542 ) Unearned premiums 105,602 105,602 — Insurance and reinsurance balances payable 25,897 23,559 (2,338 ) Other liabilities 1,864 1,864 — TOTAL LIABILITIES 473,110 464,230 (8,880 ) NET ASSETS (LIABILITIES) $ (52,768 ) $ (37,169 ) $ 15,599
Pro Forma Condensed Combined Statement of Earnings	The table below summarizes the results of the KaylaRe operations, which are included in our consolidated statement of earnings from the acquisition date to December 31, 2018: Premiums earned $ 13,627 Incurred losses and LAE (12,364 ) Acquisition costs (341 ) Underwriting income 922 Net investment income 3,096 Net unrealized gains (47,769 ) General and administrative expenses (2,164 ) Net loss $ (45,915 )

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Estimated Fair Values of Investments in Fixed Maturity Investments, Short-Term Investments and Equities, Trading Securities	The fair values of the underlying asset types of our short-term investments and fixed maturity investments, classified as trading and available-for-sale, and the fixed maturity investments included within our funds held - directly managed balance were as follows as of December 31, 2019 and 2018 : 2019 Short-term investments, trading Short-term investments, available-for-sale Fixed maturities, trading Fixed maturities, available-for-sale Fixed maturities, funds held - directly managed Total U.S. government and agency $ — $ 111,583 $ 219,194 $ 298,729 $ 106,537 $ 736,043 U.K. government 24,411 1,069 122,012 14,280 — 161,772 Other government 21,958 387 575,018 84,760 20,734 702,857 Corporate 5,121 13,915 4,007,386 1,067,256 603,389 5,697,067 Municipal — 1,381 102,554 14,491 49,456 167,882 Residential mortgage-backed — — 258,412 127,219 86,205 471,836 Commercial mortgage-backed — — 571,129 98,557 230,343 900,029 Asset-backed — — 490,624 208,097 76,681 775,402 Total fixed maturity and short-term investments $ 51,490 $ 128,335 $ 6,346,329 $ 1,913,389 $ 1,173,345 $ 9,612,888 2018 Short-term investments, trading Fixed maturities, trading Fixed maturities, available-for-sale Fixed maturities, funds held - directly managed Total U.S. government and agency $ 45,885 $ 389,735 $ 573 $ 74,052 $ 510,245 U.K. government 2,275 298,356 — — 300,631 Other government 19,064 679,525 73,185 22,036 793,810 Corporate 44,900 4,081,793 75,359 637,788 4,839,840 Municipal — 73,856 2,480 53,929 130,265 Residential mortgage-backed — 682,962 12 90,583 773,557 Commercial mortgage-backed — 488,598 — 224,465 713,063 Asset-backed 1,992 553,968 — 80,521 636,481 Total fixed maturity and short-term investments $ 114,116 $ 7,248,793 $ 151,609 $ 1,183,374 $ 8,697,892
Summary of Amortized Cost and Estimated Fair Value of Fixed Maturity and Short-term Investments by Contractual Maturity	The contractual maturities of our short-term investments and fixed maturity investments, classified as trading and available-for-sale, and the fixed maturity investments included within our funds held - directly managed balance are shown below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call o r prepayment penalties. As of December 31, 2019 Amortized Cost Fair Value % of Total Fair Value One year or less $ 537,944 $ 536,156 5.6 % More than one year through two years 801,473 808,071 8.4 % More than two years through five years 2,175,547 2,212,834 23.0 % More than five years through ten years 2,108,172 2,198,505 22.9 % More than ten years 1,584,345 1,710,055 17.8 % Residential mortgage-backed 466,932 471,836 4.9 % Commercial mortgage-backed 882,603 900,029 9.4 % Asset-backed 779,279 775,402 8.0 % $ 9,336,295 $ 9,612,888 100.0 %
Credit Ratings Company's Fixed Maturity and Short-Term Investments Available-for-Sale	The following table sets forth the credit ratings of our short-term investments and fixed maturity investments, classified as trading and available-for-sale, and the fixed maturity investments included within our funds held - directly managed balance as of December 31, 2019 : Amortized Cost Fair Value % of Total AAA Rated AA Rated A Rated BBB Rated Non- Investment Grade Not Rated U.S. government and agency $ 730,396 $ 736,043 7.7 % $ 736,043 $ — $ — $ — $ — $ — U.K. government 155,261 161,772 1.7 % — 161,772 — — — — Other government 684,117 702,857 7.3 % 316,151 154,072 63,270 144,557 24,807 — Corporate 5,479,839 5,697,067 59.2 % 149,108 619,707 2,911,867 1,703,328 311,167 1,890 Municipal 157,868 167,882 1.7 % 16,381 77,291 50,938 23,272 — — Residential mortgage-backed 466,932 471,836 4.9 % 381,502 47,489 2,295 1,882 34,055 4,613 Commercial mortgage-backed 882,603 900,029 9.4 % 632,461 89,347 95,508 66,573 6,224 9,916 Asset-backed 779,279 775,402 8.1 % 378,116 89,418 174,118 117,275 15,694 781 Total $ 9,336,295 $ 9,612,888 100.0 % $ 2,609,762 $ 1,239,096 $ 3,297,996 $ 2,056,887 $ 391,947 $ 17,200 % of total fair value 27.1 % 12.9 % 34.3 % 21.4 % 4.1 % 0.2 %
Amortized Cost and Estimated Fair Values of Company's Fixed Maturity and Short-Term Investments Classified as Available-for-Sale	The amortized cost and fair values of our fixed maturity investments classified as available-for-sale were as follows as of December 31, 2019 and 2018 : 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Non-OTTI Fair Value U.S. government and agency $ 410,842 $ 77 $ (607 ) $ 410,312 U.K. government 15,067 282 — 15,349 Other government 84,116 1,119 (88 ) 85,147 Corporate 1,081,713 4,026 (4,568 ) 1,081,171 Municipal 15,963 20 (111 ) 15,872 Residential mortgage-backed 127,704 240 (725 ) 127,219 Commercial mortgage-backed 98,928 38 (409 ) 98,557 Asset-backed 208,121 169 (193 ) 208,097 $ 2,042,454 $ 5,971 $ (6,701 ) $ 2,041,724 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Non-OTTI Fair Value U.S. government and agency $ 576 $ — $ (3 ) $ 573 Other government 72,811 1,219 (845 ) 73,185 Corporate 75,535 1,006 (1,182 ) 75,359 Municipal 2,499 — (19 ) 2,480 Residential mortgage-backed 12 — — 12 $ 151,433 $ 2,225 $ (2,049 ) $ 151,609 The following tables summarize our fixed maturity and short-term investments classified as available-for-sale in a gross unrealized loss position, as of December 31, 2019 and 2018 : 12 Months or Greater Less Than 12 Months Total 2019 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fixed maturity investments, at fair value U.S. government and agency $ — $ — $ 222,643 $ (607 ) $ 222,643 $ (607 ) Other government 1,080 (23 ) 37,796 (65 ) 38,876 (88 ) Corporate 2,754 (306 ) 461,772 (4,262 ) 464,526 (4,568 ) Municipal 128 — 12,046 (111 ) 12,174 (111 ) Residential mortgage-backed — — 65,992 (725 ) 65,992 (725 ) Commercial mortgage-backed — — 79,606 (409 ) 79,606 (409 ) Asset-backed — — 129,014 (193 ) 129,014 (193 ) Total fixed maturity and short-term investments $ 3,962 $ (329 ) $ 1,008,869 $ (6,372 ) $ 1,012,831 $ (6,701 ) 12 Months or Greater Less Than 12 Months Total 2018 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fixed maturity and short-term investments, at fair value U.S. government and agency $ 573 $ (3 ) $ — $ — $ 573 $ (3 ) Other government 7,351 (345 ) 11,000 (500 ) 18,351 (845 ) Corporate 11,888 (629 ) 25,227 (553 ) 37,115 (1,182 ) Municipal 1,783 (18 ) 283 (1 ) 2,066 (19 ) Residential mortgage-backed 12 — — — 12 — Total fixed maturity and short-term investments $ 21,607 $ (995 ) $ 36,510 $ (1,054 ) $ 58,117 $ (2,049 )
Schedule Of Equity Securities	The following table summarizes our equity investments classified as trading as of December 31, 2019 and 2018 : 2019 2018 Publicly traded equity investments in common and preferred stocks $ 327,875 $ 138,415 Exchange-traded funds 133,047 — Privately held equity investments in common and preferred stocks 268,799 228,710 $ 729,721 $ 367,125
Other Investments	The following table summarizes our other investments carried at fair value as of December 31, 2019 and 2018 : 2019 2018 Hedge funds $ 1,121,904 $ 852,584 Fixed income funds 481,039 403,858 Equity funds 410,149 333,681 Private equity funds 329,885 248,628 CLO equity funds 87,509 37,260 CLO equities 87,555 39,052 Private credit funds — 33,381 Others 6,379 9,313 $ 2,524,420 $ 1,957,757 December 31, 2019 : Less than 1 Year 1-2 years 2-3 years More than 3 years Not Eligible/ Restricted Total Redemption Frequency Hedge funds $ 343,005 $ 624,233 $ — $ 102,600 $ 52,066 $ 1,121,904 Monthly to Bi-annually Fixed income funds 477,935 — — — 3,104 481,039 Daily to Quarterly Equity funds 410,149 — — — — 410,149 Daily to Quarterly Private equity funds — — — 329,885 329,885 N/A CLO equity funds 60,735 — 26,774 — — 87,509 Quarterly to Bi-annually CLO equities 87,555 — — — — 87,555 N/A Other 34 — — — 6,345 6,379 N/A $ 1,379,413 $ 624,233 $ 26,774 $ 102,600 $ 391,400 $ 2,524,420
Equity Method Investments	The table below shows our equity method investments as of December 31, 2019 and 2018 : 2019 2018 Investment Ownership % Carrying Value Investment Ownership % Carrying Value Enhanzed Re $ 154,050 47.4 % $ 182,856 $ 94,800 47.4 % $ 94,800 Citco 50,000 31.9 % 51,742 50,000 31.9 % 50,812 Monument 26,600 26.6 % 60,598 26,600 26.6 % 42,193 Clear Spring 11,210 20.0 % $ 10,645 11,210 20.0 % 10,070 Other 24,963 ~30% 20,436 15,250 ~30% 6,632 $ 266,823 $ 326,277 $ 197,860 $ 204,507
Funds Held, Directly Managed, Carrying Values of Assets	The following table summarizes the components of the funds held - directly managed as of December 31, 2019 and 2018 : 2019 2018 Fixed maturity investments, trading $ 1,173,345 $ 1,183,374 Other assets 14,207 14,780 $ 1,187,552 $ 1,198,154
Funds Held, Directly Managed, Fair Value To Amortized Cost	The following table summarizes the fixed maturity investment components of funds held - directly managed as of December 31, 2019 and 2018 : 2019 2018 Funds held - Directly Managed - Fair Value Option Funds held - Directly Managed - Variable Return Total Funds held - Directly Managed - Fair Value Option Funds held - Directly Managed - Variable Return Total Fixed maturity investments, at amortized cost $ 185,859 $ 940,194 $ 1,126,053 $ 179,670 $ 1,044,377 $ 1,224,047 Net unrealized gains (losses): Change in fair value - fair value option accounting 5,438 — 5,438 (2,733 ) — (2,733 ) Change in fair value - embedded derivative accounting — 41,854 41,854 — (37,940 ) (37,940 ) Fixed maturity investments within funds held - directly managed, at fair value $ 191,297 $ 982,048 $ 1,173,345 $ 176,937 $ 1,006,437 $ 1,183,374
Investment Income	Major categories of net investment income for the years ended December 31, 2019 , 2018 and 2017 are summarized as follows: 2019 2018 2017 Fixed maturity investments $ 233,310 $ 189,000 $ 144,367 Short-term investments and cash and cash equivalents 16,607 12,117 9,314 Funds held 19,981 10,041 601 Funds held – directly managed 38,173 37,623 32,479 Investment income from fixed maturities and cash and cash equivalents 308,071 248,781 186,761 Equity investments 16,671 5,397 4,355 Other investments 11,792 19,703 14,337 Life settlements and other — 6,511 14,370 Investment income from equities and other investments 28,463 31,611 33,062 Gross investment income 336,534 280,392 219,823 Investment expenses (15,258 ) (9,721 ) (11,034 ) Net investment income $ 321,276 $ 270,671 $ 208,789
Realized Gain (Loss) on Investments	Components of net realized and unrealized gains (losses) for the years ended December 31, 2019 , 2018 and 2017 were as follows: 2019 2018 2017 Net realized gains (losses) on sale: Gross realized gains on fixed maturity securities, available-for-sale securities (1) $ 4,856 $ 27 $ 616 Gross realized losses on fixed maturity securities, available-for-sale securities (1) (962 ) (90 ) (125 ) Net realized gains (losses) on fixed maturity securities, trading 91,313 (27,646 ) 4,695 Net realized gains (losses) on fixed maturity securities in funds held - directly managed portfolios 1,495 (3,940 ) (4,219 ) Net realized gains (losses) on equity investments, trading (374 ) 4,016 701 Total net realized gains (losses) on sale 96,328 (27,633 ) 1,668 Net unrealized gains (losses): Fixed maturity securities, trading 349,975 (165,187 ) 35,878 Fixed maturity securities in funds held - directly managed portfolios 88,053 (46,257 ) 33,902 Equity investments, trading 55,359 (9,831 ) 16,498 Other investments 441,636 (163,976 ) 102,388 Total net unrealized gains (losses) 935,023 (385,251 ) 188,666 Net realized and unrealized gains (losses) $ 1,031,351 $ (412,884 ) $ 190,334 (1) The gross realized gains and losses on available-for-sale investments included in the table above resulted from sales of $310.4 million , $11.4 million and $40.8 million for the years ended December 31, 2019 , 2018 and 2017 , respectively.
Unrealized Gain (Loss) on Investments	Components of net realized and unrealized gains (losses) for the years ended December 31, 2019 , 2018 and 2017 were as follows: 2019 2018 2017 Net realized gains (losses) on sale: Gross realized gains on fixed maturity securities, available-for-sale securities (1) $ 4,856 $ 27 $ 616 Gross realized losses on fixed maturity securities, available-for-sale securities (1) (962 ) (90 ) (125 ) Net realized gains (losses) on fixed maturity securities, trading 91,313 (27,646 ) 4,695 Net realized gains (losses) on fixed maturity securities in funds held - directly managed portfolios 1,495 (3,940 ) (4,219 ) Net realized gains (losses) on equity investments, trading (374 ) 4,016 701 Total net realized gains (losses) on sale 96,328 (27,633 ) 1,668 Net unrealized gains (losses): Fixed maturity securities, trading 349,975 (165,187 ) 35,878 Fixed maturity securities in funds held - directly managed portfolios 88,053 (46,257 ) 33,902 Equity investments, trading 55,359 (9,831 ) 16,498 Other investments 441,636 (163,976 ) 102,388 Total net unrealized gains (losses) 935,023 (385,251 ) 188,666 Net realized and unrealized gains (losses) $ 1,031,351 $ (412,884 ) $ 190,334
Schedule of Carrying Value of Restricted Investments	The carrying value of our restricted assets, including restricted cash of $352.7 million and $380.5 million , as of December 31, 2019 and 2018 , respectively, was as follows: 2019 2018 Collateral in trust for third party agreements $ 4,104,093 $ 4,336,752 Assets on deposit with regulatory authorities 445,626 579,048 Collateral for secured letter of credit facilities 133,238 127,841 Funds at Lloyd's (1) 639,316 354,589 $ 5,322,273 $ 5,398,230 (1) Our businesses include three Lloyd's syndicates. Lloyd's determines the required capital principally through the annual business plan of each syndicate. This capital is referred to as "Funds at Lloyd's" and will be drawn upon in the event that a syndicate has a loss that cannot be funded from other sources. We also utilize unsecured letters of credit for Funds at Lloyd's, as described in Note 15 - "Debt Obligations and Credit Facilities" . Funds at Lloyd's increased primarily due to reinsurance to close ("RITC") transactions, during 2019 .

Derivatives and Hedging Instr_2

Derivatives and Hedging Instruments (Tables)	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Foreign Currency Forward Exchange Contracts	The following table presents the gross notional amounts and the estimated fair values recorded within other assets and liabilities related to our qualifying foreign currency forward exchange rate contracts as of December 31, 2019 and 2018 : 2019 2018 Fair Value Fair Value Gross Notional Amount Assets Liabilities Gross Notional Amount Assets Liabilities Foreign exchange forward - AUD $ 64,620 $ 52 $ 2,033 $ 42,258 $ 1,377 $ — Foreign exchange forward - EUR 112,284 246 1,635 66,422 238 300 Foreign exchange forward - GBP 318,387 344 7,784 — — — Total qualifying hedges $ 495,291 $ 642 $ 11,452 $ 108,680 $ 1,615 $ 300 The following table presents the amounts of the net gains and losses deferred in the cumulative translation adjustment ("CTA") account, which is a component of accumulated other comprehensive income (loss) ("AOCI"), in shareholders' equity, relating to our foreign currency forward exchange rate contracts for the years ended December 31, 2019 , 2018 and 2017 : Amount of Gains (Losses) Deferred in AOCI 2019 2018 2017 Foreign exchange forward - AUD $ (722 ) $ 3,438 $ (1,247 ) Foreign exchange forward - EUR 1,817 1,000 — Foreign exchange forward - GBP (16,423 ) — — Total qualifying hedges $ (15,328 ) $ 4,438 $ (1,247 ) Amount of Gains (Losses) Deferred in AOCI 2018 2017 Net gains (losses) on qualifying non-derivative hedges 3,144 (9,375 ) The following table presents the gross notional amounts and the estimated fair values recorded within other assets and liabilities as of December 31, 2019 and 2018 and the gains and losses during the years ended December 31, 2019 and 2018 , related to our non-qualifying foreign currency forward exchange rate hedging relationships : December 31, 2019 2019 Fair Value Gross Notional Amount Assets Liabilities Gains (losses) on non-qualifying hedges charged to earnings Foreign exchange forward - AUD $ 913 $ 839 $ 892 $ 1,523 Foreign exchange forward - CAD 66,266 10 1,482 (2,079 ) Foreign exchange forward - EUR 74,444 507 1,440 1,759 Foreign exchange forward - GBP 11,940 13 292 12,004 Total non-qualifying hedges $ 153,563 $ 1,369 $ 4,106 $ 13,207 December 31, 2018 2018 Fair Value Gross Notional Amount Assets Liabilities Gains (losses) on non-qualifying hedges charged to earnings Foreign exchange forward - AUD $ 45,427 $ 1,952 $ 310 $ 4,958 Foreign exchange forward - CAD 55,050 1,441 — 9,311 Foreign exchange forward - EUR 54,282 139 301 2,296 Foreign exchange forward - GBP 256,959 1,554 72 15,078 Total non-qualifying hedges $ 411,718 $ 5,086 $ 683 $ 31,643

Reinsurance Balances Recovera_2

Reinsurance Balances Recoverable on Paid and Unpaid Losses (Tables)	12 Months Ended
	Dec. 31, 2019
Insurance [Abstract]
Summary of Reinsurance Reserves Recoverable	The following table provides the total reinsurance balances recoverable on paid and unpaid losses as of December 31, 2019 and 2018 : 2019 Non-life Run-off Atrium StarStone Total Recoverable from reinsurers on unpaid: Outstanding losses $ 972,293 $ 9,011 $ 328,009 $ 1,309,313 IBNR 673,059 19,286 211,404 903,749 Fair value adjustments - acquired companies (13,652 ) 519 (2,122 ) (15,255 ) Fair value adjustments - fair value option (88,086 ) — — (88,086 ) Total reinsurance reserves recoverable 1,543,614 28,816 537,291 2,109,721 Paid losses recoverable 181,375 1,541 87,253 270,169 Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 Reconciliation to Consolidated Balance Sheet: Reinsurance balances recoverable on paid and unpaid losses $ 1,029,471 $ 30,357 $ 624,544 $ 1,684,372 Reinsurance balances recoverable on paid and unpaid losses - fair value option 695,518 — — 695,518 Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 2018 Non-life Run-off Atrium StarStone Total Recoverable from reinsurers on unpaid: Outstanding losses $ 901,772 $ 18,891 $ 263,065 $ 1,183,728 IBNR 609,434 19,247 201,784 830,465 Fair value adjustments - acquired companies (14,344 ) 630 (1,899 ) (15,613 ) Fair value adjustments - fair value option (130,739 ) — — (130,739 ) Total reinsurance reserves recoverable 1,366,123 38,768 462,950 1,867,841 Paid losses recoverable 138,265 (256 ) 23,813 161,822 Total $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 Reconciliation to Consolidated Balance Sheet: Reinsurance balances recoverable on paid and unpaid losses $ 764,797 $ 38,512 $ 486,763 $ 1,290,072 Reinsurance balances recoverable on paid and unpaid losses - fair value option 739,591 — — 739,591 Total $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 The following table shows our reinsurance balances recoverable on paid and unpaid losses by rating of reinsurer and our provisions for uncollectible reinsurance balances recoverable on paid and unpaid losses ("provisions for bad debt") as of December 31, 2019 and 2018 . The majority of the provisions for bad debt relate to the Non-life Run-off segment. 2019 2018 Gross Provisions for Bad Debt Net Provisions as a Gross Provisions for Bad Debt Net Provisions as a Reinsurers rated A- or above $ 1,904,268 $ 43,427 $ 1,860,841 2.3 % $ 1,612,464 $ 51,519 $ 1,560,945 3.2 % Reinsurers rated below A-, secured 487,608 — 487,608 — % 430,852 — 430,852 — % Reinsurers rated below A-, unsecured 135,653 104,212 31,441 76.8 % 143,079 105,213 37,866 73.5 % Total $ 2,527,529 $ 147,639 $ 2,379,890 5.8 % $ 2,186,395 $ 156,732 $ 2,029,663 7.2 % The following tables provide a summary of net premiums written and earned for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Premiums Written Premiums Earned Premiums Written Premiums Earned Premiums Written Premiums Earned Non-life Run-off Gross $ (25,069 ) $ 197,009 $ (8,910 ) $ 25,230 $ 14,102 $ 23,950 Ceded (269 ) (28,513 ) (307 ) (15,803 ) (7,620 ) (9,788 ) Net $ (25,338 ) $ 168,496 $ (9,217 ) $ 9,427 $ 6,482 $ 14,162 Atrium Gross $ 192,373 $ 182,678 $ 171,494 $ 164,428 $ 153,472 $ 152,278 Ceded (20,017 ) (18,619 ) (18,006 ) (18,113 ) (19,258 ) (17,531 ) Net $ 172,356 $ 164,059 $ 153,488 $ 146,315 $ 134,214 $ 134,747 StarStone Gross $ 917,555 $ 1,021,827 $ 1,121,135 $ 1,010,816 $ 895,160 $ 865,159 Ceded (182,126 ) (219,901 ) (315,573 ) (295,857 ) (430,259 ) (405,756 ) Net $ 735,429 $ 801,926 $ 805,562 $ 714,959 $ 464,901 $ 459,403 Other Gross $ 18,534 $ 20,544 $ 32,378 $ 25,237 $ 5,719 $ 5,900 Ceded (22 ) (164 ) (311 ) (363 ) (926 ) (1,091 ) Net $ 18,512 $ 20,380 $ 32,067 $ 24,874 $ 4,793 $ 4,809 Total Gross $ 1,103,393 $ 1,422,058 $ 1,316,097 $ 1,225,711 $ 1,068,453 $ 1,047,287 Ceded (202,434 ) (267,197 ) (334,197 ) (330,136 ) (458,063 ) (434,166 ) Net $ 900,959 $ 1,154,861 $ 981,900 $ 895,575 $ 610,390 $ 613,121
Reinsurance Balances Recoverable by Reinsurer	December 31, 2019 December 31, 2018 Non-life Atrium StarStone Total % of Non-life Atrium StarStone Total % of Top ten reinsurers $ 1,154,110 $ 22,051 $ 388,171 $ 1,564,332 65.7 % $ 1,124,079 $ 25,239 $ 263,192 $ 1,412,510 69.6 % Other reinsurers > $1 million 551,636 7,761 233,871 793,268 33.4 % 364,098 12,091 220,123 596,312 29.4 % Other reinsurers < $1 million 19,243 545 2,502 22,290 0.9 % 16,211 1,182 3,448 20,841 1.0 % Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 100.0 % $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 100.0 % December 31, 2019 December 31, 2018 Information regarding top ten reinsurers: Number of top 10 reinsurers rated A- or better 8 7 Number of top 10 non-rated reinsurers (1) 2 3 Recoverables rated A- or better in top 10 $ 1,292,207 $ 1,096,272 Collaterized non-rated reinsurers recoverables in top 10 (1) 272,125 316,238 $ 1,564,332 $ 1,412,510 Single reinsurers that represent 10% or more of total reinsurance balance recoverables as of December 31, 2019: Hannover Ruck SE (2) $ 261,295 $ 279,723 Lloyd's Syndicates (3) $ 411,030 $ 334,509 (1) For the two non-rated reinsurers as of December 31, 2019 and three non-rated reinsurers as at December 31, 2018 , we hold security in the form of pledged assets in trust or letters of credit issued to us in the full amount of the recoverable. (2) Hannover Ruck SE is rated AA- by Standard & Poor’s and A+ by A.M. Best. (3) Lloyd's Syndicates are rated A+ by Standard & Poor's and A by A.M. Best.

Deferred Charge Assets (Tables)

Deferred Charge Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Insurance [Abstract]
Deferred Charge Assets	The following table presents a reconciliation of the deferred charge assets for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Beginning carrying value $ 86,585 $ 80,192 $ 94,551 Recorded during the year 224,504 20,174 — Amortization (38,627 ) (13,781 ) (14,359 ) Ending carrying value $ 272,462 $ 86,585 $ 80,192

Losses and Loss Adjustment Ex_2

Losses and Loss Adjustment Expenses (Tables)	12 Months Ended
	Dec. 31, 2019
Insurance [Abstract]
Total Losses and Loss Adjustment Expense Liabilities, and Reconciliation of Beginning and Ending Balances	The following table summarizes the liability for losses and LAE by segment and for our other activities as of December 31, 2019 and 2018 : 2019 Non-life Run-off Atrium StarStone Other Total Outstanding losses $ 4,407,082 $ 89,141 $ 888,794 $ 9,512 $ 5,394,529 IBNR 3,945,407 136,543 962,353 13,565 5,057,868 Fair value adjustments - acquired companies (170,689 ) 3,700 (522 ) — (167,511 ) Fair value adjustments - fair value option (217,933 ) — — — (217,933 ) ULAE 331,494 2,288 28,503 — 362,285 Total $ 8,295,361 $ 231,672 $ 1,879,128 $ 23,077 $ 10,429,238 Reconciliation to Consolidated Balance Sheet: Losses and loss adjustment expenses $ 5,674,239 $ 231,672 $ 1,879,128 $ 23,077 $ 7,808,116 Losses and loss adjustment expenses, at fair value 2,621,122 — — — 2,621,122 Total $ 8,295,361 $ 231,672 $ 1,879,128 $ 23,077 $ 10,429,238 2018 Non-life Atrium StarStone Other Total Outstanding losses $ 4,271,769 $ 94,885 $ 796,194 $ 6,052 $ 5,168,900 IBNR 3,527,767 140,521 787,894 12,809 4,468,991 Fair value adjustments- acquired companies (217,527 ) 3,476 (467 ) — (214,518 ) Fair value adjustments - fair value option (374,752 ) — — — (374,752 ) ULAE 333,405 2,402 25,076 — 360,883 Total $ 7,540,662 $ 241,284 $ 1,608,697 $ 18,861 $ 9,409,504 Reconciliation to Consolidated Balance Sheet: Losses and loss adjustment expenses $ 4,666,607 $ 241,284 $ 1,608,697 $ 18,861 $ 6,535,449 Losses and loss adjustment expenses, at fair value 2,874,055 — — — 2,874,055 Total $ 7,540,662 $ 241,284 $ 1,608,697 $ 18,861 $ 9,409,504 The table below provides a consolidated reconciliation of the beginning and ending liability for losses and LAE for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Balance as at January 1 $ 9,409,504 $ 7,398,088 $ 5,987,867 Less: reinsurance reserves recoverable 1,867,841 1,870,033 1,388,193 Less: deferred charge assets on retroactive reinsurance 86,585 80,192 94,551 Net balance as at January 1 7,455,078 5,447,863 4,505,123 Net incurred losses and LAE: Current period 823,658 689,782 437,853 Prior periods 48,917 (235,757 ) (244,302 ) Total net incurred losses and LAE 872,575 454,025 193,551 Net paid losses: Current period (200,264 ) (189,560 ) (82,273 ) Prior periods (1,669,004 ) (1,194,985 ) (862,921 ) Total net paid losses (1,869,268 ) (1,384,545 ) (945,194 ) Effect of exchange rate movement 48,695 (145,243 ) 158,429 Acquired on purchase of subsidiaries 686 1,310,874 10,251 Assumed business 1,586,307 1,772,104 1,525,703 Ceded business (47,018 ) — — Net balance as at December 31 8,047,055 7,455,078 5,447,863 Plus: reinsurance reserves recoverable 2,109,721 1,867,841 1,870,033 Plus: deferred charge assets on retroactive reinsurance 272,462 86,585 80,192 Balance as at December 31 $ 10,429,238 $ 9,409,504 $ 7,398,088 The table below provides a reconciliation of the beginning and ending reserves for losses and LAE for the years ended December 31, 2019 , 2018 and 2017 for the Non-life Run-off segment: 2019 2018 2017 Balance as at January 1 $ 7,540,662 $ 5,949,472 $ 4,716,363 Less: reinsurance reserves recoverable 1,366,123 1,377,485 1,000,953 Less: deferred charge assets on retroactive reinsurance 86,585 80,192 94,551 Net balance as at January 1 6,087,954 4,491,795 3,620,859 Net incurred losses and LAE: Current period 123,559 12,451 5,866 Prior periods (71,934 ) (318,518 ) (196,540 ) Total net incurred losses and LAE 51,625 (306,067 ) (190,674 ) Net paid losses: Current period (64,820 ) (5 ) (2,835 ) Prior periods (1,182,804 ) (838,812 ) (578,888 ) Total net paid losses (1,247,624 ) (838,817 ) (581,723 ) Effect of exchange rate movement 47,355 (132,632 ) 138,772 Acquired on purchase of subsidiaries 686 1,111,839 10,251 Assumed business 1,586,307 1,761,836 1,494,310 Ceded business (47,018 ) — — Net balance as at December 31 6,479,285 6,087,954 4,491,795 Plus: reinsurance reserves recoverable 1,543,614 1,366,123 1,377,485 Plus: deferred charge assets on retroactive reinsurance 272,462 86,585 80,192 Balance as at December 31 $ 8,295,361 $ 7,540,662 $ 5,949,472 The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Balance as at January 1 $ 241,284 $ 240,873 $ 212,122 Less: reinsurance reserves recoverable 38,768 40,531 30,009 Net balance as at January 1 202,516 200,342 182,113 Net incurred losses and LAE: Current period 85,027 83,627 90,359 Prior periods (7,751 ) (13,817 ) (20,940 ) Total net incurred losses and LAE 77,276 69,810 69,419 Net paid losses: Current period (34,617 ) (35,537 ) (24,571 ) Prior periods (43,572 ) (28,969 ) (31,107 ) Total net paid losses (78,189 ) (64,506 ) (55,678 ) Effect of exchange rate movement 1,253 (3,130 ) 4,488 Net balance as at December 31 202,856 202,516 200,342 Plus: reinsurance reserves recoverable 28,816 38,768 40,531 Balance as at December 31 $ 231,672 $ 241,284 $ 240,873 The table below provides a reconciliation of the beginning and ending liability for losses and LAE for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Balance as at January 1 $ 1,608,697 $ 1,207,743 $ 1,059,382 Less: reinsurance reserves recoverable 462,950 452,017 357,231 Net balance as at January 1 1,145,747 755,726 702,151 Net incurred losses and LAE: Current period 598,468 578,892 341,628 Prior periods 129,168 94,491 (26,822 ) Total net incurred losses and LAE 727,636 673,383 314,806 Net paid losses: Current period (96,261 ) (150,778 ) (54,867 ) Prior periods (435,372 ) (326,352 ) (252,926 ) Total net paid losses (531,633 ) (477,130 ) (307,793 ) Effect of exchange rate movement 87 (9,481 ) 15,169 Acquired on purchase of subsidiaries — 192,981 — Assumed business — 10,268 31,393 Ceded business — — — Net balance as at December 31 1,341,837 1,145,747 755,726 Plus: reinsurance reserves recoverable 537,291 462,950 452,017 Balance as at December 31 $ 1,879,128 $ 1,608,697 $ 1,207,743
Schedule of Incurred Losses	The tables below provide the components of net incurred losses and LAE by segment and for our other activities for the years ended December 31, 2019 , 2018 and 2017 : 2019 Non-life Atrium StarStone Other Total Net losses paid $ 1,247,624 $ 78,189 $ 531,633 $ 11,822 $ 1,869,268 Net change in case and LAE reserves (530,891 ) 3,534 25,967 3,460 (497,930 ) Net change in IBNR reserves (813,582 ) (4,782 ) 166,427 756 (651,181 ) Increase (reduction) in estimates of net ultimate losses (96,849 ) 76,941 724,027 16,038 720,157 Increase (reduction) in provisions for unallocated LAE (57,404 ) — 3,441 — (53,963 ) Amortization of deferred charge assets 38,627 — — — 38,627 Amortization of fair value adjustments 50,070 335 168 — 50,573 Changes in fair value - fair value option 117,181 — — — 117,181 Net incurred losses and LAE $ 51,625 $ 77,276 $ 727,636 $ 16,038 $ 872,575 2018 Non-life Run-off Atrium StarStone Other Total Net losses paid $ 838,817 $ 64,506 $ 477,130 $ 4,092 $ 1,384,545 Net change in case and LAE reserves (547,420 ) 6,331 75,887 4,808 (460,394 ) Net change in IBNR reserves (565,385 ) 4,091 113,879 7,999 (439,416 ) Increase (reduction) in estimates of net ultimate losses (273,988 ) 74,928 666,896 16,899 484,735 Increase (reduction) in provisions for unallocated LAE (65,401 ) — 6,753 — (58,648 ) Amortization of deferred charge assets 13,781 — — — 13,781 Amortization of fair value adjustments 12,877 (5,118 ) (266 ) — 7,493 Changes in fair value - fair value option 6,664 — — — 6,664 Net incurred losses and LAE $ (306,067 ) $ 69,810 $ 673,383 $ 16,899 $ 454,025 2017 Non-life Atrium StarStone Total Net losses paid $ 581,723 $ 55,678 $ 307,793 $ 945,194 Net change in case and LAE reserves (381,053 ) 8,338 31,685 (341,030 ) Net change in IBNR reserves (390,727 ) 7,679 (23,540 ) (406,588 ) Increase (reduction) in estimates of net ultimate losses (190,057 ) 71,695 315,938 197,576 Increase (reduction) in provisions for bad debt (1,536 ) 159 — (1,377 ) Increase (reduction) in provisions for unallocated LAE (53,810 ) 285 (187 ) (53,712 ) Amortization of deferred charge assets 14,359 — — 14,359 Amortization of fair value adjustments 10,114 (2,720 ) (945 ) 6,449 Changes in fair value - fair value option 30,256 — — 30,256 Net incurred losses and LAE $ (190,674 ) $ 69,419 $ 314,806 $ 193,551 Net incurred losses and LAE in the Non-life Run-off segment for the years ended December 31, 2019 , 2018 and 2017 were as follows: 2019 2018 2017 Prior Period Current Period Total Prior Period Current Period Total Prior Period Current Period Total Net losses paid $ 1,182,804 $ 64,820 $ 1,247,624 $ 838,812 $ 5 $ 838,817 $ 578,888 $ 2,835 $ 581,723 Net change in case and LAE reserves (553,996 ) 23,105 (530,891 ) (552,124 ) 4,704 (547,420 ) (381,450 ) 397 (381,053 ) Net change in IBNR reserves (848,776 ) 35,194 (813,582 ) (573,127 ) 7,742 (565,385 ) (393,100 ) 2,373 (390,727 ) Increase (reduction) in estimates of net ultimate losses (219,968 ) 123,119 (96,849 ) (286,439 ) 12,451 (273,988 ) (195,662 ) 5,605 (190,057 ) Reduction in provisions for bad debt — — — — — — (1,536 ) — (1,536 ) Increase (reduction) in provisions for unallocated LAE (57,844 ) 440 (57,404 ) (65,401 ) — (65,401 ) (54,071 ) 261 (53,810 ) Amortization of deferred charge assets 38,627 — 38,627 13,781 — 13,781 14,359 — 14,359 Amortization of fair value adjustments 50,070 — 50,070 12,877 — 12,877 10,114 — 10,114 Changes in fair value - fair value option 117,181 — 117,181 6,664 — 6,664 30,256 — 30,256 Net incurred losses and LAE $ (71,934 ) $ 123,559 $ 51,625 $ (318,518 ) $ 12,451 $ (306,067 ) $ (196,540 ) $ 5,866 $ (190,674 ) Net incurred losses and LAE in the Atrium segment for the years ended December 31, 2019 , 2018 and 2017 were as follows: 2019 2018 2017 Prior Period Current Period Total Prior Period Current Period Total Prior Period Current Period Total Net losses paid $ 43,572 $ 34,617 $ 78,189 $ 28,969 $ 35,537 $ 64,506 $ 31,107 $ 24,571 $ 55,678 Net change in case and LAE reserves (13,278 ) 16,812 3,534 (10,161 ) 16,492 6,331 (13,324 ) 21,662 8,338 Net change in IBNR reserves (38,380 ) 33,598 (4,782 ) (27,507 ) 31,598 4,091 (35,650 ) 43,329 7,679 Increase (reduction) in estimates of net ultimate losses (8,086 ) 85,027 76,941 (8,699 ) 83,627 74,928 (17,867 ) 89,562 71,695 Increase in provisions for bad debt — — — — — — 89 70 159 Increase (reduction) in provisions for unallocated LAE — — — — — — (442 ) 727 285 Amortization of fair value adjustments 335 — 335 (5,118 ) — (5,118 ) (2,720 ) — (2,720 ) Net incurred losses and LAE $ (7,751 ) $ 85,027 $ 77,276 $ (13,817 ) $ 83,627 $ 69,810 $ (20,940 ) $ 90,359 $ 69,419 Net incurred losses and LAE in the StarStone segment for the years ended December 31, 2019 , 2018 and 2017 were as follows: 2019 2018 2017 Prior Current Total Prior Current Total Prior Current Total Net losses paid $ 435,372 $ 96,261 $ 531,633 $ 326,352 $ 150,778 $ 477,130 $ 252,926 $ 54,867 $ 307,793 Net change in case and LAE reserves (85,983 ) 111,950 25,967 (81,491 ) 157,378 75,887 (63,785 ) 95,470 31,685 Net change in IBNR reserves (214,787 ) 381,214 166,427 (144,212 ) 258,091 113,879 (208,244 ) 184,704 (23,540 ) Increase (reduction) in estimates of net ultimate losses 134,602 589,425 724,027 100,649 566,247 666,896 (19,103 ) 335,041 315,938 Increase (reduction) in provisions for unallocated LAE (5,602 ) 9,043 3,441 (5,892 ) 12,645 6,753 (6,774 ) 6,587 (187 ) Amortization of fair value adjustments 168 — 168 (266 ) — (266 ) (945 ) — (945 ) Net incurred losses and LAE $ 129,168 $ 598,468 $ 727,636 $ 94,491 $ 578,892 $ 673,383 $ (26,822 ) $ 341,628 $ 314,806
Schedule of Gross and Net Losses and LAE Reserves by Category	For the year ended December 31, 2019 , the overall change in our estimates of net ultimate losses related to prior periods by line of business within our Non-life Run-off was as presented in the table below: Net losses paid Net change in case and LAE reserves Net change in IBNR reserves Increase (reduction) in estimates of net ultimate losses Asbestos $ 118,557 $ 35,003 $ (146,749 ) $ 6,811 Environmental 16,899 13,796 (15,707 ) 14,988 General Casualty 175,044 (89,968 ) (91,818 ) (6,742 ) Workers' Compensation 208,961 (156,435 ) (188,944 ) (136,418 ) Marine, aviation and transit 82,058 (77,958 ) (24,508 ) (20,408 ) Construction defect 32,078 (8,313 ) (25,025 ) (1,260 ) Professional indemnity/ Directors & Officers 103,413 (36,986 ) (104,984 ) (38,557 ) Motor 276,563 (134,127 ) (179,887 ) (37,451 ) Property 94,093 (73,259 ) (7,358 ) 13,476 All Other 75,138 (25,749 ) (63,796 ) (14,407 ) Total $ 1,182,804 $ (553,996 ) $ (848,776 ) $ (219,968 ) December 31, 2018 , the overall change in our estimates of net ultimate losses related to prior periods by line of business within our Non-life Run-off was as presented in the table below: Net losses paid Net change in case and LAE reserves Net change in IBNR reserves Increase (reduction) in estimates of net ultimate losses Asbestos $ 108,248 $ (21,535 ) $ (151,662 ) $ (64,949 ) Environmental 21,273 479 (7,599 ) 14,153 General Casualty 141,624 (115,240 ) (60,828 ) (34,444 ) Workers' Compensation 139,226 (178,138 ) (115,648 ) (154,560 ) Marine, aviation and transit 67,831 (44,200 ) (21,188 ) 2,443 Construction defect 22,182 (7,257 ) (33,146 ) (18,221 ) Professional indemnity/ Directors & Officers 161,797 (11,159 ) (130,957 ) 19,681 Motor 104,182 (109,962 ) (34,215 ) (39,995 ) Property 22,178 (24,271 ) (11,497 ) (13,590 ) All Other 50,271 (40,841 ) (6,387 ) 3,043 Total $ 838,812 $ (552,124 ) $ (573,127 ) $ (286,439 ) December 31, 2017 , the overall change in our estimates of net ultimate losses related to prior periods by line of business within our Non-life Run-off was as presented in the table below: Net losses paid Net change in case and LAE reserves Net change in IBNR reserves Increase (reduction) in estimates of net ultimate losses Asbestos $ 105,731 $ (1,865 ) $ (76,837 ) $ 27,029 Environmental 26,542 (9,438 ) (7,748 ) 9,356 General Casualty 94,526 (54,292 ) (49,025 ) (8,791 ) Workers' Compensation 187,712 (190,924 ) (151,797 ) (155,009 ) Marine, aviation and transit 18,272 (9,322 ) (11,517 ) (2,567 ) Construction defect 33,802 (24,023 ) (42,804 ) (33,025 ) Professional indemnity/ Directors & Officers 33,402 (19,054 ) (24,559 ) (10,211 ) Motor 24,391 (15,990 ) (8,513 ) (112 ) Property 13,440 (11,196 ) (5,162 ) (2,918 ) All Other 41,070 (45,346 ) (15,138 ) (19,414 ) Total $ 578,888 $ (381,450 ) $ (393,100 ) $ (195,662 ) The following tables provides a breakdown of gross and net losses and LAE reserves, consisting of Outstanding Loss Reserve ("OLR") and IBNR by line of business and adjustments for fair value resulting from business combinations, adjustments for where we elected the fair value option, deferred charge assets and ULAE, as of December 31, 2019 and 2018 : 2019 Gross Net OLR IBNR Total OLR IBNR Total (in thousands of U.S. dollars) Asbestos $ 542,681 $ 1,373,678 $ 1,916,359 $ 490,117 $ 1,271,982 $ 1,762,099 Environmental 187,165 156,121 343,286 173,878 142,351 316,229 General casualty 501,863 489,129 990,992 399,396 421,426 820,822 Workers' compensation/personal accident 1,270,530 977,808 2,248,338 963,578 751,074 1,714,652 Marine, aviation and transit 290,067 121,577 411,644 244,611 100,135 344,746 Construction defect 29,772 98,312 128,084 29,245 94,888 124,133 Professional indemnity/Directors & Officers 693,760 265,490 959,250 485,478 170,926 656,404 Motor 480,668 233,806 714,474 317,829 165,543 483,372 Property 140,620 63,604 204,224 122,010 56,450 178,460 Other 269,956 165,882 435,838 208,647 97,573 306,220 $ 4,407,082 $ 3,945,407 $ 8,352,489 $ 3,434,789 $ 3,272,348 $ 6,707,137 Fair value adjustments (170,689 ) (157,036 ) Fair value adjustments - fair value option (217,933 ) (129,848 ) Deferred charge on retroactive reinsurance — (272,462 ) ULAE 331,494 331,494 Total $ 8,295,361 $ 6,479,285 2018 Gross Net OLR IBNR Total OLR IBNR Total (in thousands of U.S. dollars) Asbestos $ 341,544 $ 1,275,476 $ 1,617,020 $ 321,356 $ 1,171,754 $ 1,493,110 Environmental 96,665 126,035 222,700 93,095 117,384 210,479 General casualty 500,033 379,484 879,517 416,097 298,612 714,709 Workers' compensation/personal accident 1,454,178 832,615 2,286,793 1,115,116 537,782 1,652,898 Marine, aviation and transit 301,783 72,888 374,671 227,994 78,023 306,017 Construction defect 20,712 99,288 120,000 19,310 94,736 114,046 Professional indemnity/Directors & Officers 603,665 216,839 820,504 426,020 166,898 592,918 Motor 564,307 321,992 886,299 414,847 304,874 719,721 Property 168,267 37,631 205,898 160,873 36,817 197,690 Other 220,615 165,519 386,134 175,289 111,453 286,742 $ 4,271,769 $ 3,527,767 $ 7,799,536 $ 3,369,997 $ 2,918,333 $ 6,288,330 Fair value adjustments (217,527 ) (203,183 ) Fair value adjustments - fair value option (374,752 ) (244,013 ) Deferred charge on retroactive reinsurance — (86,585 ) ULAE 333,405 333,405 Total $ 7,540,662 $ 6,087,954 The following tables provide a breakdown of the gross and net losses and LAE by line of business and the fair value adjustments resulting from business acquisitions and ULAE as of December 31, 2019 and 2018 for the Atrium segment: 2019 Gross Net OLR IBNR Total OLR IBNR Total (in thousands of U.S. dollars) Marine, Aviation and Transit $ 24,668 $ 34,156 $ 58,824 $ 21,012 $ 24,829 $ 45,841 Binding Authorities 31,507 54,039 85,546 29,590 51,984 81,574 Reinsurance 18,385 29,533 47,918 16,209 23,338 39,547 Accident and Health 5,460 7,880 13,340 4,735 7,469 12,204 Non-Marine Direct and Facultative 9,121 10,935 20,056 8,584 9,637 18,221 Total $ 89,141 $ 136,543 $ 225,684 $ 80,130 $ 117,257 $ 197,387 Fair value adjustments 3,700 3,181 ULAE 2,288 2,288 Total $ 231,672 $ 202,856 2018 Gross Net OLR IBNR Total OLR IBNR Total (in thousands of U.S. dollars) Marine, Aviation and Transit $ 32,999 $ 36,011 $ 69,010 $ 21,460 $ 24,207 $ 45,667 Binding Authorities 28,512 59,302 87,814 26,601 57,016 83,617 Reinsurance 18,547 27,653 46,200 15,180 24,823 40,003 Accident and Health 4,972 6,348 11,320 4,225 5,837 10,062 Non-Marine Direct and Facultative 9,855 11,207 21,062 8,529 9,389 17,918 Total $ 94,885 $ 140,521 $ 235,406 $ 75,995 $ 121,272 $ 197,267 Fair value adjustments 3,476 2,847 ULAE 2,402 2,402 Total $ 241,284 $ 202,516 The following tables provide a breakdown of the gross and net losses and LAE reserves by line of business and the fair value adjustments resulting from business acquisitions and ULAE as of December 31, 2019 and 2018 : 2019 Gross Net OLR IBNR Total OLR IBNR Total (in thousands of U.S. dollars) Casualty $ 191,317 $ 481,473 $ 672,790 $ 156,086 $ 422,186 $ 578,272 Marine 195,068 173,319 368,387 162,073 138,586 300,659 Property 367,258 152,514 519,772 158,156 92,655 250,811 Aerospace 79,249 33,000 112,249 47,796 22,862 70,658 Workers' Compensation 55,902 122,047 177,949 36,673 74,661 111,334 Total $ 888,794 $ 962,353 $ 1,851,147 $ 560,784 $ 750,950 $ 1,311,734 Fair value adjustments (522 ) 1,600 ULAE 28,503 28,503 Total $ 1,879,128 $ 1,341,837 2018 Gross Net OLR IBNR Total OLR IBNR Total (in thousands of U.S. dollars) Casualty $ 177,432 $ 331,432 $ 508,864 $ 137,828 $ 282,026 $ 419,854 Marine 185,084 182,453 367,537 163,889 133,426 297,315 Property 317,102 123,511 440,613 151,774 65,522 217,296 Aerospace 67,203 40,416 107,619 45,879 36,167 82,046 Workers' Compensation 49,373 110,082 159,455 33,759 68,969 102,728 Total $ 796,194 $ 787,894 $ 1,584,088 $ 533,129 $ 586,110 $ 1,119,239 Fair value adjustments (467 ) 1,432 ULAE 25,076 25,076 Total $ 1,608,697 $ 1,145,747
Incurred and Paid Loss Development Information, and IBNR Liabilities and Cumulative Loss Frequency	The following table provides a summary of our net loss reserves, prior to provisions for bad debt, fair value adjustments, deferred charge assets and ULAE as of December 31, 2019 , by year of acquisition and by significant line of business: Acquisition Year 2009 and Prior 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 Total Asbestos $ 180,887 $ 36,371 $ — $ — $ 7,973 $ — $ 673 $ 387,808 $ 729,749 $ 60,424 $ 336,925 $ 1,740,810 Environmental 44,461 10,364 — — — — — 101,649 26,798 17,247 108,094 308,613 General casualty 60,400 13,409 24,072 12,082 14,695 30,313 46,838 5,389 59,432 305,370 241,541 813,541 Workers' compensation/personal accident 3,362 49,828 145,975 3,986 58,316 — 331,383 266,932 73,069 385,223 392,454 1,710,528 Marine, aviation and transit 8,890 2,638 3,256 — — 13,762 1,589 — 81,037 139,908 91,909 342,989 Construction defect — 18 55 — — — 46,906 18,982 22,973 — 35,198 124,132 Professional indemnity/Directors & Officers 9,438 5,021 8,619 28,274 — 35,795 — 77,685 — 326,157 164,271 655,260 Motor 25,131 5,756 217 500 660 250 14,785 203 4,453 406,545 22,099 480,599 Property 3,957 4,058 298 6,199 — 14,127 3,581 — 455 66,755 78,785 178,215 All Other 17,889 13,843 422 6,295 3,361 5,587 7,600 26,528 118,979 16,562 84,344 301,410 Total $ 354,415 $ 141,306 $ 182,914 $ 57,336 $ 85,005 $ 99,834 $ 453,355 $ 885,176 $ 1,116,945 $ 1,724,191 $ 1,555,620 $ 6,656,097 Business Acquired and Contracts Incepting in the Year Ended December 31, 2010 Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Years Ended December 31, Accident Year Total Net Reserves Acquired 2010 (unaudited) 2011 (unaudited) 2012 (unaudited) 2013 (unaudited) 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 1,092,197 $ 1,086,671 $ 1,044,111 $ 1,058,458 $ 1,012,046 $ 929,888 $ 903,954 $ 839,798 $ 800,104 $ 800,341 $ 788,475 $ 42,290 163,994 $ 1,092,197 $ 788,475 $ 42,290 163,994 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For The Years Ended December 31, Accident Year 2010 (unaudited) 2011 (unaudited) 2012 (unaudited) 2013 (unaudited) 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 2009 and Prior $ 102,123 $ 261,446 $ 428,312 $ 511,054 $ 553,769 $ 567,605 $ 584,306 $ 612,530 $ 630,627 $ 647,169 $ 647,169 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 141,306 Business Acquired and Contracts Incepting in the Year Ended December 31, 2011 Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Years Ended December 31, Accident Year Total Net Reserves Acquired 2011 (unaudited) 2012 (unaudited) 2013 (unaudited) 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 596,121 $ 621,742 $ 586,636 $ 490,822 $ 424,001 $ 370,995 $ 315,912 $ 270,905 $ 256,864 $ 235,348 $ 23,721 112,787 2010 285 412 449 141 140 140 140 142 142 142 — 26 2011 — 102 36 45 54 61 71 79 86 93 — 19 2012 — 121 10 10 10 10 17 18 17 — 7 2013 — 23 43 15 15 15 15 15 — 16 2014 — 1 3 3 3 18 15 3 14 2015 — — (2 ) (2 ) 32 24 5 1 2016 — 2 (139 ) (110 ) (99 ) 8 2 2017 — — 21 15 2 2 2018 — 7 8 2 1 2019 — — — — $ 596,406 $ 235,578 $ 23,741 112,875 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For The Years Ended December 31, Accident Year 2011 (unaudited) 2012 (unaudited) 2013 (unaudited) 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 2009 and Prior $ 59,906 $ 97,414 $ 92,129 $ 21,874 $ 15,512 $ 24,434 $ 16,751 $ 27,013 $ 52,483 2010 $ 91 115 140 140 140 140 142 142 142 2011 27 36 45 54 61 71 79 86 93 2012 6 10 10 10 10 17 17 17 2013 6 10 15 15 15 15 15 2014 1 3 3 3 4 7 2015 — (2 ) (2 ) 3 11 2016 2 (153 ) (124 ) (114 ) 2017 — 3 6 2018 1 4 2019 — $ 52,664 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 182,914 Business Acquired and Contracts Incepting in the Year Ended December 31, 2012 Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Years Ended December 31, Accident Year Total Net Reserves Acquired 2012 (unaudited) 2013 (unaudited) 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 315,850 $ 314,772 $ 306,078 $ 297,612 $ 283,244 $ 273,273 $ 266,124 $ 257,947 $ 252,794 $ 18,173 47,708 2010 831 920 3,068 2,788 2,400 2,468 1,368 1,242 1,208 64 6 2011 1,360 1,341 1,222 1,081 1,002 981 960 944 944 — 5 2012 50 74 45 332 315 371 363 152 152 — 6 2013 — 866 109 390 396 385 124 124 — 5 2014 — 2,736 2,843 1,420 1,189 1,093 1,048 23 7 2015 — 667 1,388 676 676 676 — 5 2016 — 61 1,158 1,019 969 139 2 2017 — 69 153 91 — 4 2018 — — 141 18 1 2019 — 251 37 4 $ 318,091 $ 258,398 $ 18,454 47,753 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For The Years Ended December 31, Accident Year 2012 (unaudited) 2013 (unaudited) 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 2009 and Prior $ 2,754 $ 67,858 $ 108,965 $ 139,542 $ 163,845 $ 173,921 $ 187,091 $ 197,236 2010 $ 167 463 618 685 712 748 776 801 2011 110 454 679 792 849 905 944 944 2012 28 45 45 47 152 152 152 152 2013 100 109 124 124 124 124 124 2014 62 205 420 617 791 905 2015 103 107 676 676 676 2016 2 51 89 89 2017 12 39 91 2018 — 27 2019 17 $ 201,062 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 57,336 Business Acquired and Contracts Incepting in the Year Ended December 31, 2013 Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Years Ended December 31, Accident Year Total Net Reserves Acquired 2013 (unaudited) 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 207,452 $ 227,635 $ 233,644 $ 225,478 $ 218,082 $ 212,039 $ 200,034 $ 188,416 $ 15,864 44,881 2010 110,795 118,652 117,915 133,289 135,364 125,148 123,802 122,441 4,635 11,537 2011 96,929 102,288 100,482 100,243 95,848 87,913 86,403 85,920 2,218 11,175 2012 131,119 127,323 121,364 118,085 114,772 110,045 107,853 108,025 2,090 10,420 2013 13,062 90,739 91,634 88,920 85,791 81,732 80,036 80,091 1,277 5,649 2014 — 4,514 3,714 3,425 16,800 16,225 16,304 90 175 2015 — 265 280 982 329 250 54 2 2016 — 103 71 70 69 2 1 2017 — 30 13 13 — 1 2018 — 22 17 — 1 2019 — 13 3 1 $ 559,357 $ 601,559 $ 26,233 83,843 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For The Years Ended December 31, Accident Year 2013 (unaudited) 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 2009 and Prior $ 48,802 $ 84,422 $ 109,918 $ 128,474 $ 129,803 $ 136,898 $ 140,814 2010 $ 24,752 48,783 75,351 92,782 98,341 105,023 105,873 2011 30,323 52,455 63,952 70,498 75,055 77,290 79,113 2012 33,361 59,095 74,663 86,916 92,445 96,780 99,781 2013 17,022 37,653 52,638 62,876 68,866 71,487 74,556 2014 993 1,747 2,256 15,804 15,959 16,123 2015 43 102 112 165 190 2016 34 64 65 66 2017 9 13 13 2018 13 17 2019 8 $ 516,554 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 85,005 Business Acquired and Contracts Incepting in the Year Ended December 31, 2014 Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Years Ended December 31, Accident Year Total Net Reserves Acquired 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 37,554 $ 33,315 $ 23,192 $ 20,933 $ 22,105 $ 21,089 $ 19,229 $ 72 6,363 2010 104,408 100,017 100,345 133,784 119,430 115,341 122,063 10,628 6,454 2011 73,942 128,979 153,910 133,521 135,540 140,845 143,664 9,369 6,693 2012 140,683 146,060 177,122 185,261 178,247 165,223 162,068 11,175 5,086 2013 86,920 75,762 93,936 82,344 86,798 86,393 84,590 13,971 3,171 2014 — 12,826 9,503 13,817 7,420 5,765 5,589 1,731 1,113 2015 — 33,545 15,529 20,709 18,616 17,799 73 186 2016 — 330 1,075 4,607 773 89 44 2017 — 5,074 3,920 8,196 423 37 2018 — 6 5 — 17 2019 — — 899 5 $ 443,507 $ 563,976 $ 48,430 29,169 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For The Years Ended December 31, Accident Year 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 2009 and Prior $ 7,044 $ 13,090 $ 15,652 $ 16,337 $ 16,884 $ 16,934 2010 $ 29,424 69,414 87,233 102,138 102,128 103,753 2011 84,042 109,574 110,338 113,406 120,564 126,650 2012 47,495 89,618 119,807 128,692 127,958 132,508 2013 21,752 40,237 47,537 55,882 63,256 62,009 2014 1,462 2,494 3,280 3,975 5,994 7,671 2015 1,739 4,295 11,465 13,487 12,774 2016 20 556 571 601 2017 537 1,553 1,237 2018 5 5 2019 — $ 464,142 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 99,834 Business Acquired and Contracts Incepting in the Year Ended December 31, 2015 Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Years Ended December 31, Accident Year Total Net Reserves Acquired 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 953,149 $ 877,641 $ 585,616 $ 536,452 $ 508,471 $ 467,530 $ 51,305 11,285 2010 49,049 53,914 52,889 55,761 51,348 49,031 6,860 2,349 2011 124,400 137,102 130,994 129,386 127,098 127,673 18,940 5,379 2012 178,936 187,288 197,716 200,749 192,896 192,338 23,706 4,714 2013 229,182 189,430 196,205 199,593 188,572 184,189 16,027 5,182 2014 143,623 142,425 137,061 142,332 136,403 151,243 18,617 10,707 2015 22,540 69,067 68,034 65,243 63,776 68,388 5,125 21,014 2016 — 14,172 12,504 12,750 13,837 2,053 3,365 2017 — 4,056 4,497 5,194 453 900 2018 — 2,965 1,845 997 270 2019 — 1,804 1,775 3 $ 1,700,879 $ 1,263,072 $ 145,858 65,168 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For The Years Ended December 31, Accident Year 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 2009 and Prior $ 23,605 $ 67,899 $ 114,682 $ 140,691 $ 165,931 2010 $ 9,191 15,301 19,665 25,625 28,455 2011 33,826 55,077 70,975 86,324 97,842 2012 52,728 94,767 119,382 142,165 158,417 2013 46,761 89,868 120,429 145,659 159,626 2014 30,747 64,353 90,738 109,149 125,226 2015 20,653 38,193 46,067 51,315 59,247 2016 5,325 7,038 8,298 9,405 2017 2,311 3,909 4,691 2018 558 835 2019 42 $ 809,717 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 453,355 Business Acquired and Contracts Incepting in the Year Ended December 31, 2015 - Workers' Compensation Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Years Ended December 31, Accident Year Total Net Reserves Acquired 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 921,259 $ 834,148 $ 538,290 $ 488,356 $ 462,612 $ 418,931 $ 43,677 8,129 2010 31,919 34,360 31,402 30,407 27,922 26,913 1,877 471 2011 76,789 73,723 69,009 68,013 66,781 67,236 5,836 1,238 2012 120,298 110,007 108,251 106,625 100,187 98,532 5,774 1,804 2013 146,237 124,726 122,238 121,010 113,056 112,199 6,789 2,379 2014 82,141 86,852 82,038 83,095 78,389 78,457 2,633 3,680 2015 4,089 18,647 12,623 13,488 12,295 11,125 545 2,900 2016 — 873 955 583 536 72 38 2017 — 358 61 41 21 10 2018 — — 5 3 1 2019 — 1 — 1 $ 1,382,732 $ 813,976 $ 67,228 20,651 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For The Years Ended December 31, Accident Year 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 2009 and Prior $ 16,278 $ 56,563 $ 96,000 $ 115,884 $ 137,417 2010 $ 4,352 8,446 11,906 16,141 17,912 2011 16,032 30,462 39,635 50,470 55,595 2012 25,103 52,851 66,092 79,367 88,369 2013 27,737 55,675 75,065 91,559 100,890 2014 17,824 38,051 53,308 65,561 72,696 2015 3,034 5,672 7,917 9,169 9,248 2016 134 363 417 447 2017 2 10 18 2018 — 1 2019 — $ 482,593 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 331,383 Business Acquired and Contracts Incepting in the Year Ended December 31, 2016 Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Years Ended December 31, Accident Year Total Net Reserves Acquired 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 1,263,726 $ 1,274,524 $ 1,302,307 $ 1,282,385 $ 1,287,000 $ 303,592 22,892 2010 32,571 32,451 32,866 28,093 25,710 5,047 706 2011 17,291 17,291 19,920 19,754 18,829 2,830 789 2012 13,717 13,717 17,020 14,765 12,717 2,012 776 2013 373 373 1,312 1,237 1,120 827 112 2014 391 391 1,380 1,056 869 485 50 2015 — — — — — — — 2016 — — — — — — — 2017 — — — — — — 2018 — — — — — 2019 — — — — $ 1,328,069 $ 1,346,245 $ 314,793 25,325 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, Accident Year 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 2009 and Prior $ 96,937 $ 213,509 $ 317,309 $ 428,904 2010 $ 2,757 7,111 10,001 14,236 2011 2,758 6,647 8,218 9,691 2012 2,734 5,206 6,461 7,587 2013 145 191 278 285 2014 178 207 284 366 2015 — — — — 2016 — — — — 2017 — — — 2018 — — 2019 — $ 461,069 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 885,176 Business Acquired and Contracts Incepting in the Year Ended December 31, 2016 - Workers' Compensation Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Years Ended December 31, Accident Year Total Net Reserves Acquired 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 413,381 $ 412,474 $ 377,285 $ 369,093 $ 362,905 $ 26,747 9,092 2010 24,075 25,330 26,034 22,383 19,541 3,660 323 2011 15,376 15,376 16,399 16,501 16,327 1,456 476 2012 13,074 13,074 15,465 13,276 11,379 1,093 608 2013 — — — — — — — 2014 — — — — — — — 2015 — — — — — — — 2016 — — — — — — — 2017 — — — — — — 2018 — — — — — 2019 — — — — $ 465,906 $ 410,152 $ 32,956 10,499 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, Accident Year 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 2009 and Prior $ 33,610 $ 59,725 $ 83,273 $ 117,191 2010 $ 1,908 5,539 7,326 9,891 2011 2,631 5,871 7,305 8,756 2012 2,638 5,028 6,247 7,382 2013 — — — — 2014 — — — — 2015 — — — — 2016 — — — — 2017 — — — 2018 — — 2019 — $ 143,220 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 266,932 Business Acquired and Contracts Incepting in the Year Ended December 31, 2017 Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Years Ended December 31, Accident Year Total Net Reserves Acquired 2017 (unaudited) 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 1,449,663 $ 1,374,191 $ 1,304,002 $ 1,313,517 $ 776,522 11,481 2010 34,561 28,737 18,908 21,021 8,209 36 2011 36,184 29,273 25,390 27,315 8,573 7 2012 39,449 35,467 31,240 29,452 6,389 11 2013 36,320 30,335 28,140 24,703 1,242 11 2014 31,474 20,315 16,984 15,996 2,195 20 2015 9,207 6,494 7,002 6,295 931 8 2016 1,484 (4 ) 125 919 86 3 2017 95 174 — — 416 1 2018 — — — — — 2019 — — — — $ 1,638,437 $ 1,439,218 $ 804,563 11,578 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, Accident Year 2017 (unaudited) 2018 (unaudited) 2019 2009 and Prior $ 80,189 $ 165,471 $ 243,621 2010 $ 4,287 7,394 9,121 2011 4,125 9,257 12,971 2012 10,348 15,371 18,603 2013 9,508 15,711 21,277 2014 6,482 8,987 11,559 2015 1,361 3,720 4,687 2016 (56 ) 66 434 2017 4 — — 2018 — — 2019 — $ 322,273 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 1,116,945 Business Acquired and Contracts Incepting in the Year Ended December 31, 2018 Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Year Ended December 31, Accident Year Total Net Reserves Acquired 2018 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 559,105 $ 383,948 $ 355,392 $ 106,822 209,846 2010 88,147 108,810 94,273 23,039 13,799 2011 159,362 147,341 142,391 21,380 14,100 2012 225,177 219,807 211,156 20,218 14,055 2013 263,008 267,132 255,973 54,609 16,251 2014 408,726 453,181 423,289 90,111 18,887 2015 354,692 474,678 467,650 97,189 23,421 2016 170,311 172,245 174,845 55,384 2,094 2017 207,035 207,172 205,460 79,430 4,163 2018 315,659 315,659 285,038 88,411 4,929 2019 — 68,271 19,774 1,634 $ 2,751,222 $ 2,683,738 $ 656,367 323,179 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2018 2019 2009 and Prior $ 41,953 $ 36,359 2010 $ 11,109 23,761 2011 26,998 47,261 2012 31,845 74,768 2013 42,312 90,716 2014 93,536 181,166 2015 100,598 191,150 2016 6,258 62,658 2017 52 72,794 2018 — 139,815 2019 39,099 $ 959,547 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 1,724,191 Business Acquired and Contracts Incepting in the Year Ended December 31, 2018 - General Casualty Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Year Ended December 31, Accident Year Total Net Reserves Acquired 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 97,189 $ 48,898 $ 42,901 $ 3,969 45,895 2010 30,895 23,086 23,059 7,004 1,885 2011 17,518 15,854 15,532 2,086 1,404 2012 36,536 31,901 27,774 3,716 1,567 2013 42,528 54,061 44,782 5,123 1,571 2014 65,355 80,316 72,333 16,793 2,210 2015 77,011 91,825 102,399 28,926 3,430 2016 28,825 28,825 36,585 14,377 253 2017 37,209 37,209 41,664 20,392 230 2018 39,888 39,888 40,753 20,480 182 2019 — 6,767 2,802 34 $ 472,954 $ 454,549 $ 125,668 58,661 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2018 (unaudited) 2019 2009 and Prior $ 3,496 $ 7,146 2010 $ 5,345 7,835 2011 2,236 6,621 2012 1,104 11,097 2013 10,015 19,756 2014 13,427 28,071 2015 15,163 32,244 2016 — 14,109 2017 — 11,048 2018 — 8,879 2019 2,373 $ 149,179 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 305,370 Business Acquired and Contracts Incepting in the Year Ended December 31, 2018 - Workers' Compensation Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Year Ended December 31, Accident Year Total Net Reserves Acquired 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 106,230 $ 101,016 $ 108,435 $ 30,391 1,742 2010 24,838 25,149 24,102 8,642 355 2011 29,795 24,877 26,179 12,202 401 2012 28,788 29,174 27,723 12,633 468 2013 37,716 38,309 37,866 16,786 866 2014 65,000 66,305 57,128 24,865 1,335 2015 38,734 39,336 34,649 16,909 1,437 2016 44,686 44,686 38,945 21,267 892 2017 52,360 52,360 49,156 28,222 998 2018 65,075 65,075 60,923 24,137 886 2019 — 20,889 5,472 383 $ 493,222 $ 485,995 $ 201,526 9,763 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2018 (unaudited) 2019 2009 and Prior $ 3,633 $ 10,643 2010 $ 317 4,542 2011 (1,517 ) 1,825 2012 521 5,513 2013 1,532 7,743 2014 3,248 14,666 2015 1,355 4,066 2016 — 3,666 2017 — 5,900 2018 — 28,725 2019 13,483 $ 100,772 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 385,223 Business Acquired and Contracts Incepting in the Year Ended December 31, 2018 - Marine, Aviation & Transit Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Year Ended December 31, Accident Year Total Net Reserves Acquired 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 26,321 $ 28,798 $ 20,641 $ (1,842 ) 57,002 2010 3,324 2,062 (6,710 ) (1,049 ) 3,243 2011 8,676 9,472 10,345 1,486 3,966 2012 16,069 12,297 10,151 (6,037 ) 4,280 2013 43,798 35,462 29,464 2,404 5,720 2014 62,766 81,126 82,479 14,668 5,862 2015 26,007 65,209 72,055 8,758 6,606 2016 — — — — — 2017 — — — — — 2018 — — — — — 2019 — — — — $ 186,961 $ 218,425 $ 18,388 86,679 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2018 (unaudited) 2019 2009 and Prior $ 3,211 $ (3,789 ) 2010 $ (3,689 ) (7,715 ) 2011 4,953 5,901 2012 1,180 3,482 2013 5,642 11,734 2014 22,990 40,926 2015 21,956 27,978 2016 — — 2017 — — 2018 — — 2019 — $ 78,517 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 139,908 Business Acquired and Contracts Incepting in the Year Ended December 31, 2018 - Professional Indemnity/Directors & Officers Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Year Ended December 31, Accident Year Total Net Reserves Acquired 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 200,658 $ 92,577 $ 100,687 $ (1,316 ) 52,393 2010 25,474 39,710 33,765 8,220 4,259 2011 44,476 50,663 46,111 2,837 3,745 2012 55,366 68,004 65,180 12,943 3,263 2013 56,251 60,010 74,018 9,407 3,223 2014 84,795 106,888 101,771 16,922 3,563 2015 45,515 97,288 79,028 19,285 3,903 2016 — — — — — 2017 — — — — — 2018 — — — — — 2019 — — — — $ 512,535 $ 500,560 $ 68,298 74,349 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2018 (unaudited) 2019 2009 and Prior $ 24,232 $ 33,585 2010 $ 3,644 12,243 2011 12,453 19,732 2012 15,706 22,837 2013 10,599 18,601 2014 21,640 40,189 2015 13,696 27,216 2016 — — 2017 — — 2018 — — 2019 — $ 174,403 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 326,157 Business Acquired and Contracts Incepting in the Year Ended December 31, 2018 - Motor Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Year Ended December 31, Accident Year Total Net Reserves Acquired 2018 (unaudited) 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 17,648 $ 15,490 $ 10,781 $ (291 ) 356 2010 23,548 13,937 15,187 1,015 922 2011 46,015 36,282 35,843 1,477 1,209 2012 62,432 55,338 60,620 6,949 1,594 2013 74,615 68,022 61,396 14,105 626 2014 111,418 99,140 86,887 10,440 1,140 2015 129,271 127,187 126,345 15,912 1,274 2016 90,166 92,100 93,824 19,439 644 2017 100,316 100,453 99,129 30,312 2,797 2018 180,471 180,471 157,556 42,546 3,731 2019 — 39,757 11,457 1,200 $ 835,900 $ 787,325 $ 153,361 15,493 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2018 (unaudited) 2019 2009 and Prior $ 2,398 $ 5,112 2010 $ 4,437 6,911 2011 5,631 12,112 2012 11,520 23,284 2013 10,226 27,839 2014 20,746 46,359 2015 19,857 58,433 2016 6,258 42,527 2017 52 48,655 2018 — 86,861 2019 22,687 $ 380,780 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 406,545 Business Acquired and Contracts Incepting in the Year Ended December 31, 2019 Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Year Ended December 31, Accident Year Total Net Reserves Acquired 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 604,631 $ 598,841 $ 330,575 81,869 2010 35,515 24,353 3,586 21,945 2011 47,718 38,961 1,506 21,380 2012 70,661 51,937 27,520 15,532 2013 110,426 87,708 36,879 19,223 2014 135,465 131,000 76,169 21,224 2015 182,991 186,727 99,838 35,276 2016 238,798 308,254 179,237 39,815 2017 116,386 116,386 116,386 2 2018 162,744 162,744 162,744 2 2019 — 54,601 12,706 85 $ 1,705,335 $ 1,761,512 $ 1,047,146 256,353 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2019 2009 and Prior $ 21,678 2010 4,923 2011 4,649 2012 6,455 2013 12,893 2014 26,910 2015 34,610 2016 68,179 2017 — 2018 — 2019 25,595 $ 205,892 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 1,555,620 Business Acquired and Contracts Incepting in the Year Ended December 31, 2019 - General Casualty Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Year Ended December 31, Accident Year Total Net Reserves Acquired 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 4,396 $ 4,415 $ 670 693 2010 7,704 5,426 1,509 1,213 2011 11,381 8,817 2,347 1,148 2012 16,910 13,592 5,262 688 2013 22,355 16,934 7,515 448 2014 32,883 30,337 15,387 456 2015 58,563 45,594 30,556 346 2016 50,518 62,866 44,899 475 2017 32,188 32,188 32,188 1 2018 45,010 45,010 45,010 1 2019 — 1,709 475 3 $ 281,908 $ 266,888 $ 185,818 5,472 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2019 2009 and Prior $ 1,163 2010 1,031 2011 896 2012 3,136 2013 3,472 2014 4,103 2015 4,552 2016 6,193 2017 — 2018 — 2019 801 $ 25,347 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 241,541 Business Acquired and Contracts Incepting in the Year Ended December 31, 2019 - Workers' Compensation Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Year Ended December 31, Accident Year Total Net Reserves Acquired 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 5,143 $ 3,609 $ 1,270 11,136 2010 713 726 642 1,352 2011 2,470 2,410 2,334 1,476 2012 6,274 6,173 6,090 2,102 2013 16,686 16,223 14,578 3,726 2014 34,945 35,252 30,998 3,956 2015 57,027 56,158 48,794 6,158 2016 84,171 85,396 73,087 6,612 2017 84,197 84,197 84,197 1 2018 117,734 117,734 117,734 1 2019 — — — — $ 409,360 $ 407,878 $ 379,724 36,520 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2019 2009 and Prior $ 577 2010 38 2011 24 2012 24 2013 451 2014 3,076 2015 3,635 2016 7,599 2017 — 2018 — 2019 — $ 15,424 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 392,454 Business Acquired and Contracts Incepting in the Year Ended December 31, 2019 - Professional Indemnity/Directors & Officers Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance As of December 31, 2019 For the Year Ended December 31, Accident Year Total Net Reserves Acquired 2019 IBNR Cumulative Number of Claims 2009 and Prior $ 6,696 $ 4,052 $ 812 10,399 2010 7,245 4,448 838 5,300 2011 18,093 10,292 1,947 6,511 2012 30,127 18,012 4,348 3,472 2013 46,758 35,881 9,945 4,411 2014 46,557 46,982 17,975 5,361 2015 29,527 32,577 7,665 5,856 2016 2,892 52,708 28,916 5,053 2017 — — — — 2018 — — — — 2019 — 3,251 961 3 $ 187,895 $ 208,203 $ 73,407 46,366 Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2019 2009 and Prior $ 1,323 2010 326 2011 3,403 2012 3,216 2013 3,924 2014 14,955 2015 7,193 2016 8,067 2017 — 2018 — 2019 1,525 $ 43,932 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 164,271 The following tables set forth information about incurred and paid loss development information for the Atrium segment as of December 31, 2019 . The information related to incurred and paid loss development for the years ended December 31, 2010 through 2018 is presented as supplementary information and is therefore unaudited. Information about total IBNR reserves and cumulative loss frequency as of December 31, 2019 , including expected development on reported losses included within the net incurred losses and allocated LAE amounts for the Atrium segment, are set forth in the table below. Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, As of December 31, 2019 Accident Year 2010 (unaudited) 2011 (unaudited) 2012 (unaudited) 2013 (unaudited) 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 IBNR (1) Cumulative Number of Claims 2009 and Prior 546,446 609,275 593,467 573,576 569,959 564,128 560,524 558,768 556,252 553,325 2,839 1,381 2010 26,782 64,985 57,835 51,698 47,558 46,024 45,540 44,289 43,739 43,723 518 201 2011 86,326 84,661 72,898 71,104 69,385 68,083 67,358 66,904 66,534 991 252 2012 70,259 57,279 55,903 53,723 51,930 51,012 50,541 50,352 601 385 2013 58,326 63,710 57,798 54,472 51,706 52,049 50,638 1,441 566 2014 69,253 69,500 66,104 60,542 57,667 56,737 3,104 932 2015 69,646 71,498 63,530 60,210 58,785 6,018 1,515 2016 73,190 75,318 70,179 67,031 10,449 2,803 2017 90,247 94,984 91,109 20,400 5,053 2018 85,044 91,621 37,297 6,644 2019 86,269 33,598 5,362 Total $ 1,216,124 $ 117,257 25,094 (1) Total of IBNR plus expected development on reported losses. Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For The Years Ended December 31, Accident Year 2010 (unaudited) 2011 (unaudited) 2012 (unaudited) 2013 (unaudited) 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 2009 and Prior $ 491,683 $ 510,113 $ 521,740 $ 531,928 $ 536,706 $ 541,597 $ 543,591 $ 544,954 $ 543,253 $ 544,625 2010 11,442 25,127 32,223 36,530 39,022 40,049 40,650 41,223 41,386 41,631 2011 17,138 39,997 52,450 58,627 62,560 63,914 65,199 64,669 65,040 2012 11,228 31,474 37,991 42,152 44,430 45,321 46,901 47,598 2013 14,579 32,064 40,443 43,511 45,387 46,099 46,637 2014 17,596 34,368 41,595 46,879 48,542 51,263 2015 12,029 29,687 38,987 44,544 47,704 2016 13,729 34,606 44,273 47,962 2017 14,371 47,723 56,057 2018 13,130 34,166 2019 36,054 Total $ 1,018,737 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 197,387 Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For The Years Ended December 31, As of December 31, 2019 Accident Year 2014 (Unaudited) 2015 (Unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 IBNR (1) Cumulative Number of Claims 2009 and Prior $ 82,278 $ 82,329 $ 82,400 $ 82,324 $ 82,535 $ 82,574 $ — 2,543 2010 16,623 17,769 17,856 18,538 18,556 18,612 119 729 2011 21,101 25,435 25,745 24,971 25,422 26,159 765 2,035 2012 56,891 48,251 43,936 40,095 39,477 42,055 3,059 3,128 2013 72,771 66,888 77,756 76,172 78,788 87,575 9,817 4,998 2014 91,369 92,793 92,812 90,335 90,588 101,748 19,074 5,734 2015 105,135 111,067 110,179 123,208 131,156 22,056 4,744 2016 125,367 129,130 140,601 169,207 39,548 4,467 2017 137,614 162,599 194,259 64,639 4,830 2018 159,324 181,499 90,672 3,902 2019 198,218 172,437 2,780 Total $ 1,233,062 $ 422,186 39,890 (1) Total of IBNR plus expected development on reported losses. Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For The Years Ended December 31, Accident Year 2014 (Unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 2009 and Prior $ 82,257 $ 82,319 $ 82,395 $ 82,318 $ 82,534 $ 82,546 2010 15,555 17,768 17,855 18,537 18,555 18,466 2011 15,745 21,088 23,731 24,294 24,925 25,389 2012 18,412 29,503 32,694 33,943 36,162 36,076 2013 23,054 30,448 50,137 54,688 60,389 69,703 2014 5,769 21,911 37,607 50,767 64,672 68,827 2015 8,088 27,292 49,014 68,194 92,327 2016 4,642 42,935 74,921 97,715 2017 9,997 50,705 107,625 2018 20,649 47,973 2019 8,143 Total $ 654,790 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 578,272 Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance For The Years Ended December 31, As of December 31, 2019 Accident Year 2014 (unaudited) 2015 (unaudited) 2016 (unaudited) 2017 (unaudited) 2018 (unaudited) 2019 IBNR (1) Cumulative Number of Claims 2009 and Prior $ 27,070 $ 27,002 $ 27,018 $ 27,050 $ 27,076 $ 27,100 $ — 1,991 2010 22,347 19,270 19,114 19,176 19,040 19,050 144 1,029 2011 29,527 27,753 27,330 27,371 27,715 33,538 514 1,961 2012 47,957 51,418 51,074 49,813 50,618 59,597 405 2,422 2013 62,904 55,154 52,938 53,913 57,224 46,309 243 2,226 2014 50,079 53,452 48,450 54,958 50,576 50,026 833 4,003 2015 71,004 70,033 79,494 81,088 82,698 1,082 5,742 2016 82,486 83,070 87,169 86,774 4,214 6,904 2017 130,700 158,785 166,042 10,802 8,524 201
Short-duration Insurance Contracts, Reconciliation Of Net Loss Reserves Prior To Provision For Bad Debt	The table below reconciles the net loss reserves, prior to provisions for bad debt, fair value adjustments, deferred charge assets and ULAE as of December 31, 2019 , by significant line of business to the line of business table presented above: 2019 Total Net Reserves per all Acquisition Years Provision for Bad Debt Total Net Reserves Asbestos $ 1,740,810 $ 21,289 $ 1,762,099 Environmental 308,613 7,616 316,229 General casualty 813,541 7,281 820,822 Workers' compensation/personal accident 1,710,528 4,124 1,714,652 Marine, aviation and transit 342,989 1,757 344,746 Construction defect 124,132 1 124,133 Professional indemnity/Directors & Officers 655,260 1,144 656,404 Motor 480,599 2,773 483,372 Property 178,215 245 178,460 All Other 301,410 4,810 306,220 Total $ 6,656,097 $ 51,040 $ 6,707,137
Reconciliation of Incurred and Paid Loss Development to Liability for Unpaid Losses and LAE	The reconciliation of incurred and paid loss development to the liability for unpaid losses and LAE as presented in the tables above for the Atrium segment for the year ended December 31, 2019 is set forth below: 2019 Liabilities for unpaid losses and allocated LAE, net of reinsurance $ 197,387 Reinsurance recoverable on unpaid losses 28,297 Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments $ 225,684 The reconciliation of incurred and paid loss development to the liability for unpaid losses and LAE as presented in the tables above for the year ended December 31, 2019 is set forth below: 2019 Liabilities for unpaid losses and allocated LAE, net of reinsurance $ 578,272 Reinsurance recoverable on unpaid losses 94,518 Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments $ 672,790 The reconciliation of incurred and paid loss development to the liability for unpaid losses and LAE as presented in the tables above for the year ended December 31, 2019 is set forth below: 2019 Liabilities for unpaid losses and allocated LAE, net of reinsurance $ 300,659 Reinsurance recoverable on unpaid losses 67,728 Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments $ 368,387 The reconciliation of incurred and paid loss development to the liability for unpaid losses and LAE as presented in the tables above for the year ended December 31, 2019 is set forth below: 2019 Liabilities for unpaid losses and allocated LAE, net of reinsurance $ 250,811 Reinsurance recoverable on unpaid losses 268,961 Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments $ 519,772 The reconciliation of incurred and paid loss development to the liability for unpaid losses and LAE as presented in the tables above for the year ended December 31, 2019 is set forth below: 2019 Liabilities for unpaid losses and allocated LAE, net of reinsurance $ 70,658 Reinsurance recoverable on unpaid losses 41,591 Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments $ 112,249 The reconciliation of incurred and paid loss development to the liability for unpaid losses and LAE as presented in the tables above for the year ended December 31, 2019 is set forth below: 2019 Liabilities for unpaid losses and allocated LAE, net of reinsurance $ 111,334 Reinsurance recoverable on unpaid losses 66,615 Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments $ 177,949
Average Annual Duration of Claims	The following is unaudited supplementary information, which presents the annual percentage payout since the year of acquisition, by year of acquisition and significant line of business within each acquisition year: Annual Percentage Payout of Incurred Losses since Year of Acquisition, Net of Reinsurance Year of Acquisition Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 2010 - All lines of business 12.95 % 20.21 % 21.16 % 10.49 % 5.42 % 1.75 % 2.12 % 3.58 % 2.30 % 2.10 % 2011 - All lines of business 25.48 % 15.94 % (2.22 )% (29.82 )% (2.70 )% 3.79 % (3.32 )% 4.38 % 10.83 % 2012 - All lines of business 1.18 % 25.49 % 16.08 % 12.00 % 9.56 % 4.26 % 5.22 % 4.02 % 2013 - All lines of business 25.64 % 21.47 % 15.78 % 10.91 % 6.08 % 3.86 % 2.14 % 2014 - All lines of business 33.91 % 23.93 % 10.99 % 7.95 % 3.44 % 2.08 % 2015 - All lines of business 17.22 % 16.89 % 12.71 % 9.69 % 7.60 % 2015 - Workers' compensation 13.56 % 16.89 % 12.58 % 9.62 % 6.64 % 2016 - All lines of business 7.84 % 9.46 % 8.15 % 8.80 % 2016 - Workers' Compensation 9.94 % 8.63 % 6.82 % 9.53 % 2017 - All lines of business 8.08 % 7.62 % 6.69 % 2018 - All lines of business 13.22 % 22.54 % 2018 - General Casualty 11.17 % 21.65 % 2018 - Workers' Compensation 1.87 % 18.87 % 2018 - Marine, Aviation & Transit 25.75 % 10.20 % 2018 - Professional Indemnity/Directors & Officers 20.37 % 14.47 % 2018 - Motor 10.30 % 38.06 % 2019 - All lines of business 11.69 % 2019 - General Casualty 9.50 % 2019 - Workers' Compensation 3.78 % 2019 - Professional Indemnity/Directors & Officers 21.10 % The following is unaudited supplementary information for average annual historical duration of claims within the Atrium segment: Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Atrium 24.69 % 32.30 % 14.57 % 8.25 % 4.69 % 2.47 % 1.88 % 0.63 % 0.47 % 0.56 % The following is unaudited supplementary information for average annual historical duration of claims: Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Casualty 5.87 % 17.83 % 17.73 % 17.98 % 13.06 % 5.94 % 3.72 % 1.44 % 0.71 % (0.23 )% The following is unaudited supplementary information for average annual historical duration of claims: Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Marine 18.70 % 29.98 % 19.76 % 9.79 % 5.60 % 3.86 % 4.63 % 0.32 % (0.09 )% 0.30 % The following is unaudited supplementary information for average annual historical duration of claims: Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Property 20.98 % 29.19 % 27.01 % 8.82 % 2.69 % 3.22 % 0.54 % 1.04 % — % 0.20 % The following is unaudited supplementary information for average annual historical duration of claims: Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Aerospace 37.03 % 31.40 % 16.33 % 4.98 % 4.76 % 3.00 % 1.81 % 2.68 % 1.21 % 0.29 % The following is unaudited supplementary information for average annual historical duration of claims: Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Workers' compensation 13.40 % 28.61 % 19.73 % 12.35 % 4.99 % 2.51 % — % — % — % — %

Defendant Asbestos and Enviro_2

Defendant Asbestos and Environmental Liabilities (Tables)	12 Months Ended
	Dec. 31, 2019
Liability for Asbestos and Environmental Claims [Abstract]
Schedule Of Liability For Asbestos And Liability Claims	The carrying value of the asbestos and environmental liabilities, insurance recoveries, future estimated expenses and the fair value adjustments related to DCo and Morse TEC as of December 31, 2019 and 2018 was as follows: 2019 2018 Defendant asbestos and environmental liabilities: Defendant asbestos liabilities $ 1,100,593 $ 265,975 Defendant environmental liabilities 10,279 2,152 Estimated future expenses 51,637 19,843 Fair value adjustments (314,824 ) (84,650 ) Defendant asbestos and environmental liabilities 847,685 203,320 Insurance balances recoverable: Insurance recoveries related to defendant asbestos and environmental liabilities 549,593 183,676 Fair value adjustments (100,738 ) (47,868 ) Insurance balances recoverable 448,855 135,808 Net liabilities relating to defendant asbestos and environmental exposures $ 398,830 $ 67,512
Reconciliation of Asbestos and Environmental Liabilities	The table below provides a consolidated reconciliation of the beginning and ending liability for defendant asbestos and environmental exposures for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Balance as at January 1 203,320 219,164 234,020 Less: Insurance balances recoverable 135,808 122,326 133,032 Net balance as at January 1 67,512 96,838 100,988 Total net paid claims (13,708 ) (6,351 ) (6,927 ) Amounts recorded in other income (expense): Net change in actuarial estimates (4,263 ) (23,221 ) 2,800 Amortization of fair value adjustments 13,500 246 (23 ) Total other expense (income) 9,237 (22,975 ) 2,777 Acquired on purchase of subsidiaries 335,789 — — Net balance as at December 31 398,830 67,512 96,838 Plus: Insurance balances recoverable 448,855 135,808 122,326 Balance as at December 31 847,685 203,320 219,164

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Categorized Investments Recorded at Fair Value among Levels	We have categorized our assets and liabilities that are recorded at fair value on a recurring basis among levels based on the observability of inputs, or at fair value using NAV per share (or its equivalent) as follows: December 31, 2019 Quoted Prices in Significant Significant Fair Value Based on NAV as Practical Expedient Total Fair Investments: Fixed maturity investments: U.S. government and agency $ — $ 736,043 $ — $ — $ 736,043 U.K. government — 161,772 — — 161,772 Other government — 702,857 — — 702,857 Corporate — 5,697,067 — — 5,697,067 Municipal — 167,882 — — 167,882 Residential mortgage-backed — 471,836 — — 471,836 Commercial mortgage-backed — 900,029 — — 900,029 Asset-backed — 775,402 — — 775,402 $ — $ 9,612,888 $ — $ — $ 9,612,888 Other assets included within funds held - directly managed — 14,207 — — 14,207 Equities: Publicly traded equity investments $ 297,310 $ 30,565 $ — $ — $ 327,875 Exchange-traded funds 133,047 — — — 133,047 Privately held equity investments — — 268,799 — 268,799 $ 430,357 $ 30,565 $ 268,799 $ — $ 729,721 Other investments: Hedge funds $ — $ — $ — $ 1,121,904 $ 1,121,904 Fixed income funds — 398,143 — 82,896 481,039 Equity funds — 111,040 — 299,109 410,149 Private equity funds — — — 329,885 329,885 CLO equities — — 87,555 — 87,555 CLO equity funds — — — 87,509 87,509 Other — 34 314 6,031 6,379 $ — $ 509,217 $ 87,869 $ 1,927,334 $ 2,524,420 Total Investments $ 430,357 $ 10,166,877 $ 356,668 $ 1,927,334 $ 12,881,236 Cash and cash equivalents $ 173,892 $ 222,191 $ — $ — $ 396,083 Reinsurance balances recoverable on paid and unpaid losses: $ — $ — $ 695,518 $ — $ 695,518 Other Assets: Derivatives qualifying as hedging $ — $ 642 $ — $ — $ 642 Derivatives not qualifying as hedges $ — $ 1,369 $ — $ — $ 1,369 Derivative instruments $ — $ 2,011 $ — $ — $ 2,011 Losses and LAE: $ — $ — $ 2,621,122 $ — $ 2,621,122 Other Liabilities: Derivatives qualifying as hedging $ — $ 11,452 $ — $ — $ 11,452 Derivatives not qualifying as hedges $ — $ 4,106 $ — $ — $ 4,106 Derivative instruments $ — $ 15,558 $ — $ — $ 15,558 December 31, 2018 Quoted Prices in Significant Significant Fair Value Based on NAV as Practical Expedient Total Fair Investments: Fixed maturity investments: U.S. government and agency $ — $ 510,245 $ — $ — $ 510,245 U.K government — 300,631 — — 300,631 Other government — 793,810 — — 793,810 Corporate — 4,802,454 37,386 — 4,839,840 Municipal — 130,265 — — 130,265 Residential mortgage-backed — 773,557 — — 773,557 Commercial mortgage-backed — 705,674 7,389 — 713,063 Asset-backed — 627,360 9,121 — 636,481 $ — $ 8,643,996 $ 53,896 $ — $ 8,697,892 Other assets included within funds held - directly managed $ — $ 14,780 $ — $ — $ 14,780 Equities: Publicly traded equity investments $ 102,102 $ 36,313 $ — $ — $ 138,415 Privately held equity investments — — 228,710 — 228,710 $ 102,102 $ 36,313 $ 228,710 $ — $ 367,125 Other investments: Hedge funds $ — $ — $ — $ 852,584 $ 852,584 Fixed income funds — 290,864 — 112,994 403,858 Equity funds — 100,440 — 233,241 333,681 Private equity funds — — — 248,628 248,628 CLO equities — — 39,052 — 39,052 CLO equity funds — — — 37,260 37,260 Private credit funds — — — 33,381 33,381 Other — 578 315 8,420 9,313 $ — $ 391,882 $ 39,367 $ 1,526,508 $ 1,957,757 Total Investments $ 102,102 $ 9,086,971 $ 321,973 $ 1,526,508 $ 11,037,554 Cash and cash equivalents $ 243,839 $ 21,146 $ — $ — $ 264,985 Reinsurance recoverable: $ — $ — $ 739,591 $ — $ 739,591 Other Assets: Derivatives qualifying as hedging $ — $ 1,615 $ — $ — $ 1,615 Derivatives not qualifying as hedges — 5,086 — — 5,086 Derivative instruments $ — $ 6,701 $ — $ — $ 6,701 Losses and LAE: $ — $ — $ 2,874,055 $ — $ 2,874,055 Other Liabilities: Derivatives qualifying as hedging $ — $ 300 $ — $ — $ 300 Derivatives not qualifying as hedges — 683 — — 683 Derivative instruments $ — $ 983 $ — $ — $ 983
Reconciliation of Beginning and Ending Balances for All Investments Measured at Fair Value on Recurring Basis	The following table presents a reconciliation of the beginning and ending balances for all investments measured at fair value on a recurring basis using Level 3 inputs during the years ended December 31, 2019 and 2018 : 2019 Fixed maturity investments Privately-held Equities Other Investments Total Corporate Residential mortgage-backed Commercial mortgage-backed Asset-backed Beginning fair value $ 37,386 $ — $ 7,389 $ 9,121 $ 228,710 $ 39,367 $ 321,973 Purchases 184 — — — 33,713 56,908 90,805 Sales (3,520 ) — (784 ) (5,088 ) (2,016 ) (590 ) (11,998 ) Total realized and unrealized gains (losses) 90 (1 ) 64 241 8,392 (7,816 ) 970 Transfer into Level 3 from Level 2 3,535 102 1,515 22,771 — — 27,923 Transfer out of Level 3 into Level 2 (37,675 ) (101 ) (8,184 ) (27,045 ) — — (73,005 ) Ending fair value $ — $ — $ — $ — $ 268,799 $ 87,869 $ 356,668 2018 Fixed maturity investments Privately-held Equities Other Investments Total Corporate Residential mortgage-backed Commercial mortgage-backed Asset-backed Beginning fair value $ 67,178 $ 3,080 $ 21,494 $ 27,892 $ — $ 57,079 $ 176,723 Purchases 14,391 — 3,749 46,074 227,000 13,173 304,387 Sales (65,700 ) (1,184 ) (5,781 ) (49,020 ) — (12,091 ) (133,776 ) Total realized and unrealized losses (57 ) (28 ) (645 ) (1,843 ) (2 ) (18,794 ) (21,369 ) Transfer into Level 3 from Level 2 28,339 1,795 4,897 9,890 1,712 — 46,633 Transfer out of Level 3 into Level 2 (6,765 ) (3,663 ) (16,325 ) (23,872 ) — — (50,625 ) Ending fair value $ 37,386 $ — $ 7,389 $ 9,121 $ 228,710 $ 39,367 $ 321,973 The following table presents a reconciliation of the beginning and ending balances for all insurance contracts measured at fair value on a recurring basis using Level 3 inputs during the years ended December 31, 2019 and 2018 : 2019 2018 Liability for losses and LAE Reinsurance balances recoverable on paid and unpaid losses Net Liability for losses and LAE Reinsurance balances recoverable on paid and unpaid losses Net Beginning fair value $ 2,874,055 $ 739,591 $ 2,134,464 $ 1,794,669 $ 542,224 $ 1,252,445 Assumed business 9,218 — 9,218 1,890,061 372,780 1,517,281 Incurred losses and LAE: Reduction in estimates of ultimate losses (32,690 ) (2,958 ) (29,732 ) (108,429 ) (30,041 ) (78,388 ) Reduction in unallocated LAE (19,915 ) — (19,915 ) (20,656 ) — (20,656 ) Change in fair value 160,630 43,449 117,181 27,845 21,181 6,664 Total incurred losses and LAE 108,025 40,491 67,534 (101,240 ) (8,860 ) (92,380 ) Paid losses (416,770 ) (92,145 ) (324,625 ) (576,949 ) (148,175 ) (428,774 ) Effect of exchange rate movements 46,594 7,581 39,013 (132,486 ) (18,378 ) (114,108 ) Ending fair value $ 2,621,122 $ 695,518 $ 1,925,604 $ 2,874,055 $ 739,591 $ 2,134,464 Changes in fair value in the table above are included in net incurred losses and LAE in our consolidated statements of earnings. The following table presents the components of the net change in fair value for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Changes in fair value due to changes in: Duration $ 22,719 $ 74,011 $ 41,332 Corporate bond yield 94,462 (71,031 ) (11,076 ) Risk cost of capital — 3,684 — Change in fair value $ 117,181 $ 6,664 $ 30,256
Valuation Techniques and Inputs	Valuations Techniques and Inputs The table below presents the quantitative information related to the fair value measurements for investments measured at fair value on a recurring basis using Level 3 inputs for the year ended December 31, 2019: Qualitative Information about Level 3 Fair Value Measurements Fair Value at December 31, 2019 Valuation Techniques Unobservable Input Range (Average) (1) (in millions of U.S. dollars) CLO equities $87.6 Consensus pricing Offered quotes 14-87 (48) Discounted Cash Flow method Discount rate (%) (2) Recovery rate (3) Prepayment rate (4) Collateral reinvestment coupon floor (5) 10%-30% (19.5%) Privately held equity investments 268.8 Transactional value Implied price at recent purchase transaction 13.50 - 13.85 Cost as approximation of fair value Cost as approximation of fair value (1) The average represents the arithmetic average of the inputs and is not weighted by the relative fair value. (2) Implied yields were determined from recent market color of comparable subordinated notes, as well as unique characteristics for each investment. (3) For collateral which has already defaulted, a recovery rate equal to the current market value of the collateral was assumed. (4) An assumed constant prepayment rate (CPR) was applied to the CLOs. CPRs are the annualized percentage of loans in the collateral pool that prepay. (5) It was assumed that the collateral manager would reinvest into collateral with a similar weighted-average spread and a similar ratings composition to the current collateral pool.
Reconciliation of Beginning and Ending Balances for All Investments Measured at Fair Value on Recurring Basis	The following table presents a reconciliation of the beginning and ending balances for all insurance contracts measured at fair value on a recurring basis using Level 3 inputs during the years ended December 31, 2019 and 2018 : 2019 2018 Liability for losses and LAE Reinsurance balances recoverable on paid and unpaid losses Net Liability for losses and LAE Reinsurance balances recoverable on paid and unpaid losses Net Beginning fair value $ 2,874,055 $ 739,591 $ 2,134,464 $ 1,794,669 $ 542,224 $ 1,252,445 Assumed business 9,218 — 9,218 1,890,061 372,780 1,517,281 Incurred losses and LAE: Reduction in estimates of ultimate losses (32,690 ) (2,958 ) (29,732 ) (108,429 ) (30,041 ) (78,388 ) Reduction in unallocated LAE (19,915 ) — (19,915 ) (20,656 ) — (20,656 ) Change in fair value 160,630 43,449 117,181 27,845 21,181 6,664 Total incurred losses and LAE 108,025 40,491 67,534 (101,240 ) (8,860 ) (92,380 ) Paid losses (416,770 ) (92,145 ) (324,625 ) (576,949 ) (148,175 ) (428,774 ) Effect of exchange rate movements 46,594 7,581 39,013 (132,486 ) (18,378 ) (114,108 ) Ending fair value $ 2,621,122 $ 695,518 $ 1,925,604 $ 2,874,055 $ 739,591 $ 2,134,464 Changes in fair value in the table above are included in net incurred losses and LAE in our consolidated statements of earnings. The following table presents the components of the net change in fair value for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Changes in fair value due to changes in: Duration $ 22,719 $ 74,011 $ 41,332 Corporate bond yield 94,462 (71,031 ) (11,076 ) Risk cost of capital — 3,684 — Change in fair value $ 117,181 $ 6,664 $ 30,256
Quantitative Information	Below is a summary of the quantitative information regarding the significant observable and unobservable inputs used in the internal model to determine fair value on a recurring basis as of December 31, 2019 and 2018 : 2019 2018 Valuation Technique Unobservable (U) and Observable (O) Inputs Weighted Average Weighted Average Internal model Corporate bond yield (O) A rated A rated Internal model Credit spread for non-performance risk (U) 0.2% 0.2% Internal model Risk cost of capital (U) 5.1% 5.0% Internal model Weighted average cost of capital (U) 8.5% 8.5% Internal model Duration - liability (U) 7.82 years 7.33 years Internal model Duration - reinsurance balances recoverable on paid and unpaid losses (U) 8.68 years 7.98 years

Premiums Written and Earned (Ta

Premiums Written and Earned (Tables)	12 Months Ended
	Dec. 31, 2019
Insurance [Abstract]
Schedule of Net Premiums Written and Earned	The following table provides the total reinsurance balances recoverable on paid and unpaid losses as of December 31, 2019 and 2018 : 2019 Non-life Run-off Atrium StarStone Total Recoverable from reinsurers on unpaid: Outstanding losses $ 972,293 $ 9,011 $ 328,009 $ 1,309,313 IBNR 673,059 19,286 211,404 903,749 Fair value adjustments - acquired companies (13,652 ) 519 (2,122 ) (15,255 ) Fair value adjustments - fair value option (88,086 ) — — (88,086 ) Total reinsurance reserves recoverable 1,543,614 28,816 537,291 2,109,721 Paid losses recoverable 181,375 1,541 87,253 270,169 Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 Reconciliation to Consolidated Balance Sheet: Reinsurance balances recoverable on paid and unpaid losses $ 1,029,471 $ 30,357 $ 624,544 $ 1,684,372 Reinsurance balances recoverable on paid and unpaid losses - fair value option 695,518 — — 695,518 Total $ 1,724,989 $ 30,357 $ 624,544 $ 2,379,890 2018 Non-life Run-off Atrium StarStone Total Recoverable from reinsurers on unpaid: Outstanding losses $ 901,772 $ 18,891 $ 263,065 $ 1,183,728 IBNR 609,434 19,247 201,784 830,465 Fair value adjustments - acquired companies (14,344 ) 630 (1,899 ) (15,613 ) Fair value adjustments - fair value option (130,739 ) — — (130,739 ) Total reinsurance reserves recoverable 1,366,123 38,768 462,950 1,867,841 Paid losses recoverable 138,265 (256 ) 23,813 161,822 Total $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 Reconciliation to Consolidated Balance Sheet: Reinsurance balances recoverable on paid and unpaid losses $ 764,797 $ 38,512 $ 486,763 $ 1,290,072 Reinsurance balances recoverable on paid and unpaid losses - fair value option 739,591 — — 739,591 Total $ 1,504,388 $ 38,512 $ 486,763 $ 2,029,663 The following table shows our reinsurance balances recoverable on paid and unpaid losses by rating of reinsurer and our provisions for uncollectible reinsurance balances recoverable on paid and unpaid losses ("provisions for bad debt") as of December 31, 2019 and 2018 . The majority of the provisions for bad debt relate to the Non-life Run-off segment. 2019 2018 Gross Provisions for Bad Debt Net Provisions as a Gross Provisions for Bad Debt Net Provisions as a Reinsurers rated A- or above $ 1,904,268 $ 43,427 $ 1,860,841 2.3 % $ 1,612,464 $ 51,519 $ 1,560,945 3.2 % Reinsurers rated below A-, secured 487,608 — 487,608 — % 430,852 — 430,852 — % Reinsurers rated below A-, unsecured 135,653 104,212 31,441 76.8 % 143,079 105,213 37,866 73.5 % Total $ 2,527,529 $ 147,639 $ 2,379,890 5.8 % $ 2,186,395 $ 156,732 $ 2,029,663 7.2 % The following tables provide a summary of net premiums written and earned for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Premiums Written Premiums Earned Premiums Written Premiums Earned Premiums Written Premiums Earned Non-life Run-off Gross $ (25,069 ) $ 197,009 $ (8,910 ) $ 25,230 $ 14,102 $ 23,950 Ceded (269 ) (28,513 ) (307 ) (15,803 ) (7,620 ) (9,788 ) Net $ (25,338 ) $ 168,496 $ (9,217 ) $ 9,427 $ 6,482 $ 14,162 Atrium Gross $ 192,373 $ 182,678 $ 171,494 $ 164,428 $ 153,472 $ 152,278 Ceded (20,017 ) (18,619 ) (18,006 ) (18,113 ) (19,258 ) (17,531 ) Net $ 172,356 $ 164,059 $ 153,488 $ 146,315 $ 134,214 $ 134,747 StarStone Gross $ 917,555 $ 1,021,827 $ 1,121,135 $ 1,010,816 $ 895,160 $ 865,159 Ceded (182,126 ) (219,901 ) (315,573 ) (295,857 ) (430,259 ) (405,756 ) Net $ 735,429 $ 801,926 $ 805,562 $ 714,959 $ 464,901 $ 459,403 Other Gross $ 18,534 $ 20,544 $ 32,378 $ 25,237 $ 5,719 $ 5,900 Ceded (22 ) (164 ) (311 ) (363 ) (926 ) (1,091 ) Net $ 18,512 $ 20,380 $ 32,067 $ 24,874 $ 4,793 $ 4,809 Total Gross $ 1,103,393 $ 1,422,058 $ 1,316,097 $ 1,225,711 $ 1,068,453 $ 1,047,287 Ceded (202,434 ) (267,197 ) (334,197 ) (330,136 ) (458,063 ) (434,166 ) Net $ 900,959 $ 1,154,861 $ 981,900 $ 895,575 $ 610,390 $ 613,121

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill and Intangible Assets	The following table presents a reconciliation of the beginning and ending goodwill and intangible assets for the years ended December 31, 2019 and 2018 : Intangible assets Goodwill Intangible assets with a definite life Intangible assets with an indefinite life Total Total Balance as of December 31, 2017 $ 73,071 $ 20,487 $ 87,031 $ 107,518 $ 180,589 Acquired during the year 41,736 — — — 41,736 Amortization — (3,600 ) — (3,600 ) (3,600 ) Balance as of December 31, 2018 $ 114,807 $ 16,887 $ 87,031 $ 103,918 $ 218,725 Amortization — (2,257 ) — (2,257 ) (2,257 ) Balance as of December 31, 2019 $ 114,807 $ 14,630 $ 87,031 $ 101,661 $ 216,468
Schedule of Goodwill	Goodwill as of December 31, 2019 and 2018 , related to our Non-life Run-off, Atrium and StarStone segments, was as follows: 2019 2018 Non-life Run-Off $ 62,959 $ 62,959 Atrium 38,848 38,848 StarStone 13,000 13,000 $ 114,807 $ 114,807
Summary of Estimated Amortization Expense of Intangible Assets	The following table provides a summary of the amortization recorded on the intangible assets for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Intangible asset amortization $ 2,257 $ 3,600 $ 4,266 The estimated future amortization expense related to our intangible assets with a definite life is as follows: Year Atrium StarStone Total 2020 $ 2,033 $ — $ 2,033 2021 2,033 — 2,033 2022 2,033 — 2,033 2023 1,975 — 1,975 2024 1,333 — 1,333 2025 and thereafter 5,223 — 5,223 Total amortization $ 14,630 $ — $ 14,630
Schedule of Finite-Lived Intangible Assets	The gross carrying value, accumulated amortization and net carrying value of intangible assets by type as of December 31, 2019 and 2018 was as follows: 2019 2018 Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value Intangible assets with a definite life: Distribution channel $ 20,000 $ (8,111 ) $ 11,889 $ 20,000 $ (6,776 ) $ 13,224 Technology 15,000 (15,000 ) — 15,000 (14,778 ) 222 Brand 7,000 (4,259 ) 2,741 7,000 (3,559 ) 3,441 Total $ 42,000 $ (27,370 ) $ 14,630 $ 42,000 $ (25,113 ) $ 16,887 Intangible assets with an indefinite life: Lloyd’s syndicate capacity $ 37,031 $ — $ 37,031 $ 37,031 $ — $ 37,031 Licenses 19,900 — 19,900 19,900 — 19,900 Management contract 30,100 — 30,100 30,100 — 30,100 Total $ 87,031 $ — $ 87,031 $ 87,031 $ — $ 87,031 The net carrying value of intangible assets by segment and by type as of December 31, 2019 and 2018 was as follows: 2019 2018 Atrium StarStone Total Atrium StarStone Total Intangible assets with a definite life: Distribution channel $ 11,889 $ — $ 11,889 $ 13,224 $ — $ 13,224 Technology — — — — 222 222 Brand 2,741 — 2,741 3,441 — 3,441 Total $ 14,630 $ — $ 14,630 $ 16,665 $ 222 $ 16,887 Intangible assets with an indefinite life: Lloyd’s syndicate capacity $ 33,031 $ 4,000 $ 37,031 $ 33,031 $ 4,000 $ 37,031 Licenses — 19,900 19,900 — 19,900 19,900 Management contract 30,100 — 30,100 30,100 — 30,100 Total $ 63,131 $ 23,900 $ 87,031 $ 63,131 $ 23,900 $ 87,031 Total intangible assets $ 77,761 $ 23,900 $ 101,661 $ 79,796 $ 24,122 $ 103,918
Schedule of Indefinite-Lived Intangible Assets	The gross carrying value, accumulated amortization and net carrying value of intangible assets by type as of December 31, 2019 and 2018 was as follows: 2019 2018 Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value Intangible assets with a definite life: Distribution channel $ 20,000 $ (8,111 ) $ 11,889 $ 20,000 $ (6,776 ) $ 13,224 Technology 15,000 (15,000 ) — 15,000 (14,778 ) 222 Brand 7,000 (4,259 ) 2,741 7,000 (3,559 ) 3,441 Total $ 42,000 $ (27,370 ) $ 14,630 $ 42,000 $ (25,113 ) $ 16,887 Intangible assets with an indefinite life: Lloyd’s syndicate capacity $ 37,031 $ — $ 37,031 $ 37,031 $ — $ 37,031 Licenses 19,900 — 19,900 19,900 — 19,900 Management contract 30,100 — 30,100 30,100 — 30,100 Total $ 87,031 $ — $ 87,031 $ 87,031 $ — $ 87,031 The net carrying value of intangible assets by segment and by type as of December 31, 2019 and 2018 was as follows: 2019 2018 Atrium StarStone Total Atrium StarStone Total Intangible assets with a definite life: Distribution channel $ 11,889 $ — $ 11,889 $ 13,224 $ — $ 13,224 Technology — — — — 222 222 Brand 2,741 — 2,741 3,441 — 3,441 Total $ 14,630 $ — $ 14,630 $ 16,665 $ 222 $ 16,887 Intangible assets with an indefinite life: Lloyd’s syndicate capacity $ 33,031 $ 4,000 $ 37,031 $ 33,031 $ 4,000 $ 37,031 Licenses — 19,900 19,900 — 19,900 19,900 Management contract 30,100 — 30,100 30,100 — 30,100 Total $ 63,131 $ 23,900 $ 87,031 $ 63,131 $ 23,900 $ 87,031 Total intangible assets $ 77,761 $ 23,900 $ 101,661 $ 79,796 $ 24,122 $ 103,918

Debt Obligations and Credit F_2

Debt Obligations and Credit Facilities (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Amounts of Loans Payable Outstanding, and Accrued Interest	Our debt obligations are as follows: Facility Origination Date Term December 31, December 31, 4.50% Senior Notes due 2022 March 10, 2017 5 years $ 348,616 $ 348,054 4.95% Senior Notes due 2029 May 28, 2019 10 years 493,600 — Total senior notes 842,216 348,054 EGL Revolving Credit Facility August 16, 2018 5 years — 15,000 2018 EGL Term Loan Facility December 27, 2018 3 years 348,991 498,485 Total debt obligations $ 1,191,207 $ 861,539
Interest Income and Interest Expense Disclosure	The table below provides a summary of the total interest expense for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Interest expense on debt obligations $ 51,245 $ 25,205 $ 25,619 Amortization of debt issuance costs 953 537 416 Funds withheld balances and other 343 475 2,067 Total interest expense $ 52,541 $ 26,217 $ 28,102

Noncontrolling Interest (Tables

Noncontrolling Interest (Tables)	12 Months Ended
	Dec. 31, 2019
Noncontrolling Interest [Abstract]
Carrying Amount of Equity Attributable to Noncontrolling Interest	The following is a reconciliation of the beginning and ending carrying amount of the equity attributable to the RNCI for the years ended December 31, 2019 and 2018 : 2019 2018 Balance at beginning of year $ 458,543 $ 479,606 Capital contributions 13,127 55,377 Dividends paid (11,556 ) (3,852 ) Net loss attributable to RNCI (12,029 ) (64,794 ) Accumulated other comprehensive income (loss) attributable to RNCI (116 ) (240 ) Change in redemption value of RNCI (9,178 ) (7,554 ) Balance at end of year $ 438,791 $ 458,543

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Comparison of Basic and Diluted Earnings per Share	The following table sets forth the computation of basic and diluted earnings per share for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Numerator: Net earnings (loss) from continuing operations $ 902,175 $ (162,354 ) $ 300,465 Net earnings from discontinued operations, net of income taxes — — 10,993 Net earnings (loss) attributable to Enstar Group Limited $ 902,175 $ (162,354 ) $ 311,458 Denominator: Weighted-average ordinary shares outstanding — basic 21,482,617 20,698,310 19,388,621 Effect of dilutive securities: Share-based compensation plans 227,878 129,746 62,732 Warrants 64,571 76,120 76,238 Weighted-average ordinary shares outstanding — diluted 21,775,066 20,904,176 19,527,591 Earnings per share attributable to Enstar Group Limited: Basic: Net earnings (loss) from continuing operations $ 42.00 $ (7.84 ) $ 15.50 Net earnings from discontinued operations, net of income taxes — — 0.56 Net earnings (loss) per ordinary share $ 42.00 $ (7.84 ) $ 16.06 Diluted (1) : Net earnings (loss) from continuing operations $ 41.43 $ (7.84 ) $ 15.39 Net earnings from discontinued operations, net of income taxes — — 0.56 Net earnings (loss) per ordinary share $ 41.43 $ (7.84 ) $ 15.95 (1) During a period of loss, the basic weighted average ordinary shares outstanding is used in the denominator of the diluted loss per ordinary share computation as the effect of including potentially dilutive securities would be anti-dilutive.

Share-Based Compensation and _2

Share-Based Compensation and Pensions (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule of Compensation Cost for Share-based Compensation Plans	The table below provides a summary of the compensation costs for all of our share-based compensation plans for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Share-based compensation plans: Restricted shares and restricted share units $ 6,564 $ 7,641 $ 7,302 Performance share units 23,582 1,968 5,832 Cash-settled stock appreciation rights 2,575 (3,316 ) 8,875 Other share-based compensation plans: Northshore incentive plan 3,652 2,792 3,156 StarStone incentive plan 223 — — Deferred compensation and ordinary share plan for non-employee directors 992 1,155 758 Employee share purchase plan 411 430 403 Total share-based compensation $ 37,999 $ 10,670 $ 26,326 The following table summarizes the number of units outstanding for the years ended December 31, 2019 , 2018 and 2017 under the Enstar Group Limited Deferred Compensation and Ordinary Share Plan for Non-Employee Directors (the "Deferred Compensation Plan"): 2019 2018 2017 Restricted share units credited to the accounts of non-employee directors 5,976 5,691 3,852 The following table summarizes the number of shares issued to employees under the Employee Share Purchase Plan for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Number of shares issued to employees 15,269 14,183 12,401 December 31, 2019 , 2018 and 2017 . 2019 2018 2017 Defined contribution plans $ 11,798 $ 11,434 $ 12,247 Defined benefit plan 684 2,243 1,988 Total pension expense $ 12,482 $ 13,677 $ 14,235
Restricted Shares, Restricted Share Units and Performance Share Units	The following ta ble summarizes the activity related to restricted shares and restricted share awards during 2019 : Number of Shares Weighted-Average Share Price Nonvested — January 1 59,936 $191.89 Granted 50,054 176.16 Vested (42,462 ) 189.98 Forfeited (2,956 ) 206.85 Nonvested — December 31 64,572 180.49 The following table summarizes the activity related to PSUs during 2019 : Number of Shares Weighted-Average Share Price Nonvested — January 1 159,168 $190.77 Granted 36,616 166.42 Increase for above target vest 27,641 188.62 Vested (2,631 ) 195.60 Forfeited (13,845 ) 198.37 Nonvested — December 31 206,949 185.61 The following table summarizes the awards granted, the unvested PSU awards at December 31, 2019 , and the performance criteria and associated performance multipliers at various levels of achievement. Grant Year Inception-to-date Activity Roll-forward Performance Criteria: Change in FDBVPS (3 year) Performance Multiplier Levels Per Award Agreements PSUs Granted at Target Forfeited Estimated Change in Multiplier Nonvested at December 31, 2019 Threshold Target Maximum Threshold Target Maximum 2017 36,321 (12,176 ) 9,560 33,705 20.00 % 30.00 % 40.00 % 50.00 % 100.00 % 150.00 % 2017 91,875 — 18,081 109,956 30.30 % 35.65 % 41.00 % 50.00 % 100.00 % 150.00 % 2018 39,682 (11,414 ) — 28,268 25.00 % 32.50 % 40.00 % 50.00 % 100.00 % 150.00 % 2019 18,308 (798 ) — 17,510 20.00 % 30.00 % 40.00 % 60.00 % 100.00 % 150.00 % 186,186 (24,388 ) 27,641 189,439
Summary of Performance Share Units and Performance Criteria and Multiplier	The following table summarizes the awards granted, the unvested units at December 31, 2019 , and the performance criteria and associated performance multipliers at various levels of achievement. Grant Year Inception-to-date Activity Roll-forward Performance Criteria: Average Annual Operating ROE Performance Multiplier Levels Per Award Agreements PSUs Granted at Target Forfeited Estimated Change in Multiplier Nonvested at December 31, 2019 Threshold Target Maximum Threshold Target Maximum 2019 18,308 (798 ) — 17,510 9.60 % 12.00 % 14.40 % 60.00 % 100.00 % 150.00 %
Summary of Performance Multipliers	At the end of each reporting period, we estimate the expected performance multiplier, as shown in the table below: Award Description 2019 2018 2017 2017 FDBVPS Type I (30.00% Target Change) 139% 50% 100% 2017 FDBVPS Type II (35.65% Target Change) 120% 50% 100% 2018 FDBVPS 100% 50% n/a 2019 FDBVPS 100% n/a n/a 2019 Average Operating ROE 100% n/a n/a
Summary of SARs Activity	The following t able summarizes the activity related to SARs during 2019 : Number of SARs Weighted-Average Exercise Price of SARs Weighted-Average Expected Term (in years) Aggregate Intrinsic Value (1) Balance, beginning of year 109,081 $ 142.37 Exercised (19,854 ) 138.07 Balance, end of year 89,227 143.33 2.39 $ 6,133 (1) The aggregate intrinsic value is calculated as the pre-tax difference between the exercise price of the underlying share awards and the closing price per share of our ordinary shares of $206.86 on December 31, 2019 .
Assumptions Used to Estimate Fair Value of SARs Using Black-Scholes Option Valuation Model	The following table sets forth the assumptions used to estimate the fair value of the SARs using the Black-Scholes option valuation model as of December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Weighted-average fair value per SAR $ 76.03 $ 45.85 $ 75.38 Weighted-average volatility 19.75 % 18.94 % 19.44 % Weighted-average risk-free interest rate 1.64 % 2.72 % 1.65 % Dividend yield 0.00 % 0.00 % 0.00 %

Income Taxation (Tables)

Income Taxation (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Earnings before Income Taxes	The following table presents earnings (loss) before income taxes by jurisdiction from continuing operations, including earnings (loss) from equity method investments, for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Domestic (Bermuda) $ 576,339 $ (232,743 ) $ 167,263 Foreign 356,317 14,347 147,148 Total earnings (loss) before income tax on continuing operations $ 932,656 $ (218,396 ) $ 314,411
Tax Expense for Income Taxes	The following table presents our current and deferred income tax expense (benefit) from continuing operations by jurisdiction for the years ended December 31, 2019 , 2018 and 2017 : 2019 2018 2017 Current: Domestic (Bermuda) $ — $ — $ — Foreign 18,433 (3,632 ) 10,299 18,433 (3,632 ) 10,299 Deferred: Domestic (Bermuda) — — — Foreign (13,996 ) (2,492 ) (16,694 ) (13,996 ) (2,492 ) (16,694 ) Total income tax expense (benefit) on continuing operations $ 4,437 $ (6,124 ) $ (6,395 )
Reconciliation of Earnings before Income Taxes Computed by Applying Effective Rate	The actual effective income tax rate differs from the statutory rate of 0% under Bermuda law to earnings (loss) from continuing operations before income taxes, including earnings (loss) from equity method investments for the years ended December 31, 2019 , 2018 and 2017 as shown in the following reconciliation: 2019 2018 2017 Earnings (loss) before income tax $ 932,656 $ (218,396 ) $ 314,411 Bermuda income taxes at statutory rate 0.0 % 0.0 % 0.0 % Foreign income tax rate differential 8.6 % 0.7 % 13.1 % Change in valuation allowance (8.2 )% (0.3 )% (34.9 )% Effect of change in foreign (U.S.) tax rate — % — % 20.3 % U.S. base erosion and anti-abuse tax 0.5 % (0.6 )% — % Other (0.4 )% 3.0 % (0.5 )% Effective tax rate 0.5 % 2.8 % (2.0 )%
Components of Deferred Tax Assets and Deferred Tax Liabilities	Significant components of the deferred tax assets and deferred tax liabilities as of December 31, 2019 and 2018 were as follows: 2019 2018 Deferred tax assets: Net operating loss carryforwards $ 159,436 $ 183,633 Insurance reserves 14,104 18,677 Unearned premiums 7,131 11,314 Lloyd's underwriting losses taxable in future periods — 6,201 Provisions for bad debt 6,172 2,594 Unrealized losses on investments — 5,160 Defendant asbestos and environmental liabilities (1) 140,000 — Other deferred tax assets — 183 Gross deferred tax assets 326,843 227,762 Valuation allowance (117,390 ) (212,113 ) Deferred tax assets 209,453 15,649 Deferred tax liabilities: Unrealized gains on investments (10,107 ) — Lloyd's underwriting profit taxable in future periods (8,852 ) — Deferred policy acquisition cost (8,267 ) — Other deferred tax liabilities (27,317 ) (16,067 ) Deferred tax liabilities (54,543 ) (16,067 ) Net deferred tax asset (liability) $ 154,910 $ (418 ) (1) Relates to the Morse TEC acquisition as described in Note 3 - "Acquisitions" . Net Deferred Tax Asset (Liability) Balance by Major Jurisdiction: December 31, 2019 2018 Net Deferred Tax Asset Net Deferred Tax Liability United States $ 169,891 $ 5,151 United Kingdom (16,074 ) (8,377 ) Other 1,093 2,808 Total $ 154,910 $ (418 )
Summary of Operating Loss Carryforwards	As of December 31, 2019 , we had net operating loss carryforwards that could be available to offset future taxable income, as follows: Tax Jurisdiction Loss Carryforwards Tax effect Expiration Operating and Capital Loss Carryforwards: United States - Net operating loss $ 513,476 $ 107,830 2024-2038 United Kingdom 224,150 38,106 Indefinitely Other 52,484 13,500 Various
Summary of Income Tax Examinations	Listed below are the tax years that remain subject to examination by a major tax jurisdiction as of December 31, 2019 : Major Tax Jurisdiction Open Tax Years United States 2016-2019 United Kingdom 2016-2019 Australia 2014-2019

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	As of December 31, 2019 and December 31, 2018 , the RNCI on our balance sheet relating to these Trident co-investment transactions was as follows: 2019 2018 Redeemable Noncontrolling Interest $ 420,499 $ 439,428 The following table presents the amounts included in our consolidated balance sheet related to our related party transactions with Stone Point and its affiliated entities: December 31, 2019 December 31, 2018 Short-term investments, available-for-sale, at fair value $ 1,431 $ — Fixed maturities, trading, at fair value 269,131 176,193 Fixed maturities, available-for-sale, at fair value 160,303 — Equities, at fair value 121,794 57,319 Other investments, at fair value: Hedge funds 18,993 19,535 Fixed income funds 381,449 324,561 Private equity funds 34,858 52,925 CLO equities 32,560 15,372 CLO equity funds 87,509 37,260 Private Debt 16,312 10,387 Real estate fund 18,106 8,025 Cash and cash equivalents 54,080 11,739 Other assets 10 5,216 Other liabilities 4,710 4,240 The following table presents the amounts included in net earnings related to our related party transactions with Stone Point and its affiliated entities: 2019 2018 2017 Net investment income $ 8,733 $ 7,424 $ 5,990 Net realized and unrealized gains (losses) 26,631 207 24,684 Total net earnings $ 35,364 $ 7,631 $ 30,674 Our consolidated statement of earnings for the years ended December 31, 2018 and 2017 included the following balances related to transactions between us and KaylaRe and KaylaRe Ltd. up until May 14, 2018, the date of acquisition: 2018 2017 Fee income due to Enstar Limited $ 1,453 $ 2,679 Transactions under KaylaRe-StarStone QS: Ceded premium earned (52,651 ) (234,079 ) Net incurred losses 31,654 155,433 Acquisition costs 18,774 99,500 Transactions under Fitzwilliam reinsurance agreement: Profit Commission — 18,843 Total net earnings (loss) $ (770 ) $ 42,376 Our consolidated balance sheet as of December 31, 2019 and 2018 included the following balances related to transactions with Hillhouse: 2019 2018 Investments in funds managed by AnglePoint, held by Enhanzed Re $ 327,799 $ 75,192 Our ownership of equity method investments 47.4 % 47.4 % Our share of Enhanzed Re's funds managed by AnglePoint $ 155,377 $ 35,641 Investment in other funds managed by Hillhouse: InRe Fund $ 918,633 $ 678,420 Other funds 232,968 166,646 $ 1,151,601 $ 845,066 Our investment in the common and preferred shares of Monument, carried in equity method investments on our consolidated balance sheet, as of December 31, 2019 and 2018 was as follows: 2019 2018 Investment in Monument $ 60,598 $ 42,193 December 31, 2019 and 2018 was as follows: 2019 2018 Investment in Clear Spring $ 10,645 $ 10,070 Our consolidated balance sheet as of December 31, 2019 and 2018 included the following balances between us and Clear Spring: 2019 2018 Balances under StarStone ceding quota share: Reinsurance balances recoverable on paid and unpaid losses $ 22,812 $ 23,718 Prepaid insurance premiums 51 13,821 Ceded payable 3,616 14,153 Ceded acquisition costs 21 3,233 Balances under assuming quota share: Losses and LAE 6,135 5,778 Unearned reinsurance premiums 13 3,455 Funds held 8,611 10,242 Our consolidated statement of earnings for the years ended December 31, 2019 and 2018 included the following amounts between us and Clear Spring: 2019 2018 2017 Amounts under StarStone ceding quota share: Ceded premium earned $ (14,994 ) $ (29,520 ) (14,256 ) Net incurred losses and LAE 6,567 18,143 9,533 Acquisition costs 356 7,035 6,718 Amounts under assuming quota share: Premium earned 3,749 7,380 3,564 Net incurred losses and LAE (2,202 ) (4,536 ) (1,181 ) Acquisition costs (92 ) (1,836 ) (1,753 ) Total net earnings (loss) $ (6,616 ) $ (3,334 ) $ 2,625 Our indirect investment in the shares of AmTrust, carried in equities on our consolidated balance sheet, as of December 31, 2019 was as follows: 2019 2018 Investment in AmTrust $ 240,115 $ 200,000 Our indirect investment in the shares of Citco, carried in equity method investments on our consolidated balance sheet, as of December 31, 2019 and 2018 was as follows: 2019 2018 Investment in Citco $ 51,742 $ 50,812 Our investment in the common shares of Enhanzed Re, carried in equity method investments on our consolidated balance sheet, as of December 31, 2019 was as follows: 2019 2018 Investment in Enhanzed Re $ 182,856 $ 94,800 Our consolidated balance sheet as of December 31, 2019 and 2018 included the following balances between us and Enhanzed Re: 2019 Balances under ceding quota share: Insurance balances payables $ 1,443 Reinsurance balances recoverable 59,601 Funds held 50,089 Other assets 1,033 Our consolidated statement of earnings for the years ended December 31, 2019 and 2018 included the following amounts between us and Enhanzed Re: 2019 Amounts under ceding quota share: Acquisition costs $ 73 Other income 749 Total net earnings (loss) $ 822

Dividend Restrictions and Sta_2

Dividend Restrictions and Statutory Financial Information (Tables)	12 Months Ended
	Dec. 31, 2019
Insurance [Abstract]
Summary of Statutory Capital and Surplus	The statutory capital and surplus amounts for the years ended December 31, 2019 and 2018 and statutory net income amounts for the years ended December 31, 2019 , 2018 and 2017 for our insurance and reinsurance subsidiaries based in Bermuda, the United Kingdom, Australia, the United States and Continental Europe are summarized in the table below which includes information relating to acquisitions from the year of acquisition: Statutory Capital and Surplus Required Actual Statutory Income 2019 2018 2019 2018 2019 2018 2017 Bermuda $ 2,138,395 $ 1,591,991 $ 4,016,663 $ 3,701,825 $ 643,683 $ 29,486 $ 390,752 U.K. 837,104 654,721 1,532,751 715,448 154,644 (52,936 ) 77,900 U.S. 364,507 392,394 861,379 660,470 121,406 (75,005 ) (5,065 ) Europe 94,334 239,582 229,344 431,863 11,816 (17,611 ) (4,245 ) Australia 18,110 22,535 37,815 26,882 4,847 1,761 (874 )

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Lease, Cost and Other Lease Information	The table below provides a summary of the compon ents of our lease cost including the gross sublease income received under sublease arrangements related to certain office spaces that we have leased to conduct our business operations for the year ended December 31, 2019 : 2019 Operating lease cost $ 13,627 Sublease income (542 ) Total lease cost $ 13,085 The table below provides a summary of the cash flow information and non-cash activity related to our operating leases for the year ended December 31, 2019 : 2019 Operating cash flow information: Cash paid for amounts included in the measurement of lease liabilities $ 11,129 Non-cash activity: Right-of-use assets obtained in exchange for lease obligations $ 57,536 Weighted-average remaining lease term and discount rate used for our operating leases are as follows for the year ended December 31, 2019 : 2019 Weighted-average remaining lease term 6.3 years Weighted-average discount rate 6.3 %
Assets And Liabilities, Lessee	The table below provides a summary of the leases recorded on our consolidated balance sheets for the year ended December 31, 2019 : Balance sheet classification 2019 Right-of-use assets Other assets $ 46,747 Current lease liabilities Other liabilities 11,403 Non-current lease liabilities Other liabilities 34,785
Lessee, Operating Lease, Liability, Maturity	Pursuant to the transition option provided in ASU 2018-11 which we elected on adoption of ASU 2016-02 on January 1, 2019 as discussed above, the following is a schedule of future minimum rental payments that were required under operating leases that had initial or remaining non-cancelable lease terms in excess of one year as of December 31, 2018: 2019 $ 9,510 2020 10,754 2021 9,772 2022 7,500 2023 6,592 2024 and beyond 21,276 $ 65,404 The table below provides a summary of the maturity of the operating lease liabilities for the year ended December 31, 2019 : 2019 2020 $ 13,663 2021 9,854 2022 8,103 2023 7,044 2024 5,358 2025 and beyond 13,119 Total lease payments 57,141 Less: Imputed interest (10,953 ) Present value of lease liabilities $ 46,188

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Summary of Operations by Segment	The following tables set forth selected and consolidated statement of earnings results by segment for the years ended December 31, 2019 , 2018 , 2017 : 2019 Non-Life Run-Off Atrium StarStone Other Total Gross premiums written $ (25,069 ) $ 192,373 $ 917,555 $ 18,534 $ 1,103,393 Net premiums written $ (25,338 ) $ 172,356 $ 735,429 $ 18,512 $ 900,959 Net premiums earned $ 168,496 $ 164,059 $ 801,926 $ 20,380 $ 1,154,861 Net incurred losses and LAE (51,625 ) (77,276 ) (727,636 ) (16,038 ) (872,575 ) Life and Annuity Policy Benefits — — — (91 ) (91 ) Acquisition costs (73,642 ) (56,956 ) (174,711 ) (642 ) (305,951 ) Operating expenses (199,756 ) (14,452 ) (120,629 ) — (334,837 ) Underwriting income (loss) (156,527 ) 15,375 (221,050 ) 3,609 (358,593 ) Net investment income 275,236 7,049 47,401 (8,410 ) 321,276 Net realized and unrealized gains 968,350 6,195 50,957 5,849 1,031,351 Fees and commission income 18,293 10,160 — — 28,453 Other income 34,809 140 338 1,883 37,170 Corporate expenses (70,689 ) (13,825 ) (7,790 ) (45,945 ) (138,249 ) Interest income (expense) (62,055 ) — (475 ) 9,989 (52,541 ) Net foreign exchange gains (losses) 9,918 (504 ) (1,538 ) 3 7,879 EARNINGS (LOSS) BEFORE INCOME TAXES 1,017,335 24,590 (132,157 ) (33,022 ) 876,746 Income tax benefit (expense) (7,250 ) (4,033 ) 6,931 (85 ) (4,437 ) Earnings (losses) from equity method investments 56,128 — (218 ) — 55,910 NET EARNINGS (LOSS) 1,066,213 20,557 (125,444 ) (33,107 ) 928,219 Net loss (earnings) attributable to noncontrolling interest (6,409 ) (8,432 ) 24,711 — 9,870 NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED 1,059,804 12,125 (100,733 ) (33,107 ) 938,089 Dividends on preferred shares — — — (35,914 ) (35,914 ) NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS $ 1,059,804 $ 12,125 $ (100,733 ) $ (69,021 ) $ 902,175 Underwriting ratios: Loss ratio 47.1 % 90.7 % Acquisition expense ratio 34.7 % 21.8 % Operating expense ratio 8.8 % 15.1 % Combined ratio 90.6 % 127.6 % 2018 Non-Life Run-Off Atrium StarStone Other Total Gross premiums written $ (8,910 ) $ 171,494 $ 1,121,135 $ 32,378 $ 1,316,097 Net premiums written $ (9,217 ) $ 153,488 $ 805,562 $ 32,067 $ 981,900 Net premiums earned $ 9,427 $ 146,315 $ 714,959 $ 24,874 $ 895,575 Net incurred losses and LAE 306,067 (69,810 ) (673,383 ) (16,899 ) (454,025 ) Life and annuity policy benefits — — — (1,003 ) (1,003 ) Acquisition costs (4,006 ) (50,646 ) (135,452 ) (2,686 ) (192,790 ) Operating expenses (158,731 ) (17,777 ) (156,726 ) — (333,234 ) Underwriting income (loss) 152,757 8,082 (250,602 ) 4,286 (85,477 ) Net investment income 226,287 5,686 35,973 2,725 270,671 Net realized and unrealized losses (381,712 ) (3,251 ) (17,672 ) (10,249 ) (412,884 ) Fees and commission income 16,466 18,622 — — 35,088 Other income (losses) 35,978 162 (541 ) (514 ) 35,085 Corporate expenses (39,093 ) (6,921 ) — (28,127 ) (74,141 ) Interest income (expense) (30,616 ) — (624 ) 5,023 (26,217 ) Net foreign exchange gains (losses) 2,534 (3,394 ) (2,856 ) 1,048 (2,668 ) EARNINGS (LOSS) BEFORE INCOME TAXES (17,399 ) 18,986 (236,322 ) (25,808 ) (260,543 ) Income tax benefit (expense) 3,581 (3,732 ) 6,327 (52 ) 6,124 Earnings from equity method investments 42,147 — — — 42,147 NET EARNINGS (LOSS) 28,329 15,254 (229,995 ) (25,860 ) (212,272 ) Net loss (earnings) attributable to noncontrolling interest (3,107 ) (6,257 ) 71,415 — 62,051 NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED 25,222 8,997 (158,580 ) (25,860 ) (150,221 ) Dividends on preferred shares — — — (12,133 ) (12,133 ) NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS $ 25,222 $ 8,997 $ (158,580 ) $ (37,993 ) $ (162,354 ) Underwriting ratios: Loss ratio 47.7 % 94.2 % Acquisition expense ratio 34.6 % 18.9 % Operating expense ratio 12.2 % 22.0 % Combined ratio 94.5 % 135.1 % 2017 Non-Life Run-Off Atrium StarStone Other Total Gross premiums written $ 14,102 $ 153,472 $ 895,160 $ 5,719 $ 1,068,453 Net premiums written $ 6,482 $ 134,214 $ 464,901 $ 4,793 $ 610,390 Net premiums earned $ 14,162 $ 134,747 $ 459,403 $ 4,809 $ 613,121 Net incurred losses and LAE 190,674 (69,419 ) (314,806 ) — (193,551 ) Life and annuity policy benefits — — — (4,015 ) (4,015 ) Acquisition costs (328 ) (47,688 ) (48,012 ) (878 ) (96,906 ) Operating expenses (132,235 ) (17,444 ) (135,558 ) — (285,237 ) Underwriting income (loss) 72,273 196 (38,973 ) (84 ) 33,412 Net investment income 166,678 4,218 27,706 10,187 208,789 Net realized and unrealized gains (losses) 179,545 1,117 16,613 (6,941 ) 190,334 Fees and commission income (expense) 43,849 22,788 632 (1,166 ) 66,103 Other income 21,157 230 570 648 22,605 Corporate expenses (101,592 ) (12,142 ) — (37,014 ) (150,748 ) Interest income (expense) (28,970 ) (559 ) (1,902 ) 3,329 (28,102 ) Net foreign exchange gains (7,347 ) (5,060 ) (926 ) (4,204 ) (17,537 ) Loss on sale of subsidiary — — — (16,349 ) (16,349 ) EARNINGS (LOSS) BEFORE INCOME TAXES 345,593 10,788 3,720 (51,594 ) 308,507 Income tax benefit (expense) 6,990 (1,593 ) 988 10 6,395 Earnings from equity method investments 5,904 — — — 5,904 NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS 358,487 9,195 4,708 (51,584 ) 320,806 Net earnings from discontinued operations, net of income taxes — — — 10,993 10,993 NET EARNINGS (LOSS) 358,487 9,195 4,708 (40,591 ) 331,799 Net earnings attributable to noncontrolling interest (14,687 ) (3,772 ) (1,882 ) — (20,341 ) NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS $ 343,800 $ 5,423 $ 2,826 $ (40,591 ) $ 311,458 Underwriting ratios: Loss ratio 51.5 % 68.5 % Acquisition expense ratio 35.4 % 10.5 % Operating expense ratio 13.0 % 29.5 % Combined ratio 99.9 % 108.5 %
Schedule of Revenue from External Customers	The following table summarizes our gross premiums written for the year ended December 31, 2019 by geographic area. Geographic distribution in future years is subject to variation based upon market conditions and business strategies. Non-life Run-off Atrium StarStone Other Total Total % Total % Total % Total % Total % (In thousands of U.S. dollars, except percentages) United States $ (25,012 ) 99.7 % $ 102,199 53.1 % $ 548,683 59.8 % $ 17,239 93.0 % $ 643,109 58.2 % United Kingdom 350 (1.4 )% 12,972 6.7 % 114,822 12.5 % — — % 128,144 11.6 % Europe (265 ) 1.1 % 17,677 9.2 % 115,481 12.6 % 1,295 7.0 % 134,188 12.2 % Asia (48 ) 0.2 % 5,700 3.0 % 75,773 8.3 % — — % 81,425 7.4 % Rest of World (94 ) 0.4 % 53,825 28.0 % 62,796 6.8 % — — % 116,527 10.6 % Total $ (25,069 ) 100.0 % $ 192,373 100.0 % $ 917,555 100.0 % $ 18,534 100.0 % $ 1,103,393 100.0 %
Summary of Company's Assets by Segment	Our total assets as of December 31, 2019 and 2018 by segment were as follows: 2019 2018 Assets by Segment: Non-life Run-off $ 15,775,409 $ 13,362,749 Atrium 580,405 591,722 StarStone 3,522,353 3,416,132 Other (514,852 ) (814,333 ) Total assets $ 19,363,315 $ 16,556,270

Unaudited Condensed Quarterly_2

Unaudited Condensed Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Unaudited Condensed Quarterly Financial Data	December 31, September 30, June 30, March 31, 2019 2018 2019 2018 2019 2018 2019 2018 INCOME Net premiums earned $ 272,686 $ 231,947 $ 270,325 $ 264,597 $ 276,563 $ 228,812 $ 335,287 $ 170,219 Fees and commission income 9,007 11,455 6,587 6,950 6,178 8,352 6,681 8,331 Net investment income 79,376 68,453 85,472 69,430 77,732 66,469 78,696 66,319 Net realized and unrealized gains (losses) 152,664 (158,213 ) 148,185 (57,223 ) 269,711 (54,418 ) 460,791 (143,030 ) Other income (losses) 19,502 34,267 826 8,226 11,030 (9,351 ) 5,812 1,943 533,235 187,909 511,395 291,980 641,214 239,864 887,267 103,782 EXPENSES Net incurred losses and loss adjustment expenses 121,416 187,698 222,417 153,974 216,338 92,819 312,404 19,534 Life and annuity policy benefits (2,199 ) 786 — 423 2,194 (160 ) 96 (46 ) Acquisition costs 95,026 55,106 50,282 54,242 66,855 53,334 93,788 30,108 General and administrative expenses 129,569 106,950 113,924 102,553 117,519 102,612 112,074 95,260 Interest expense 13,519 4,644 14,950 4,640 13,036 8,922 11,036 8,011 Net foreign exchange losses (gains) 12,189 1,279 (13,631 ) 1,040 (2,587 ) (5,519 ) (3,850 ) 5,868 369,520 356,463 387,942 316,872 413,355 252,008 525,548 158,735 EARNINGS (LOSS) BEFORE INCOME TAXES 163,715 (168,554 ) 123,453 (24,892 ) 227,859 (12,144 ) 361,719 (54,953 ) Income tax benefit (expense) 22,427 10,688 (14,597 ) (746 ) (7,518 ) (3,646 ) (4,749 ) (172 ) Earnings from equity method investments 11,722 8,488 17,703 3,317 17,713 15,645 8,772 14,697 NET EARNINGS (LOSS) 197,864 (149,378 ) 126,559 (22,321 ) 238,054 (145 ) 365,742 (40,428 ) Net loss (earnings) attributable to noncontrolling interest 4,900 42,955 109 11,489 2,713 8,389 2,148 (782 ) NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED 202,764 (106,423 ) 126,668 (10,832 ) 240,767 8,244 367,890 (41,210 ) Dividends on preferred shares (8,925 ) (7,000 ) (8,925 ) (5,133 ) (8,925 ) — (9,139 ) — NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS $ 193,839 $ (113,423 ) $ 117,743 $ (15,965 ) $ 231,842 $ 8,244 $ 358,751 $ (41,210 ) Earnings Loss) per ordinary share attributable to Enstar Group Limited: Basic $ 9.02 $ (5.29 ) $ 5.48 $ (0.74 ) $ 10.79 $ 0.40 $ 16.71 $ (2.12 ) Diluted (1) : $ 8.89 $ (5.29 ) $ 5.42 $ (0.74 ) $ 10.70 $ 0.40 $ 16.57 $ (2.12 ) (1) During a period of loss, the basic weighted average ordinary shares outstanding is used in the denominator of the diluted loss per ordinary share computation as the effect of including potentially dilutive securities would be anti-dilutive.

Description of Business - Addit

Description of Business - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019Segment
Segment Reporting Information [Line Items]
Number of segments	3
Atrium
Segment Reporting Information [Line Items]
Syndicate underwriting capacity percentage	25.00%

Significant Accounting Polici_3

Significant Accounting Policies (Details) - USD ($) $ in Thousands	Jan. 01, 2020	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018	Jan. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets		$ 46,747
Present value of lease liabilities		46,188
Provisions for Bad Debt		$ 147,639		$ 156,732
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets			$ 51,600
Subsequent Event | Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit loss	$ 3,100
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in retained earnings			$ 0		$ (1,573)	$ 4,882
Retained Earnings | Subsequent Event | Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in retained earnings	$ 1,600

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details)	Oct. 30, 2019USD ($)	Dec. 27, 2018USD ($)	May 14, 2018USD ($)$ / sharesshares	Jun. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	May 13, 2018	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Asbestos and environmental liabilities						$ 2,259,600,000	$ 1,839,700,000
Goodwill						$ 114,807,000	$ 114,807,000		$ 73,071,000
Ownership percentage						47.40%	47.40%
Morse TEC
Business Acquisition [Line Items]
Asbestos and environmental liabilities	$ 700,000,000
Cash paid	0
Intangible assets acquired	0
Goodwill	0
Gain on bargain purchase	$ 0
Maiden Re
Business Acquisition [Line Items]
Cash paid		$ 286,375,000
Goodwill		$ 0
KaylaRe
Business Acquisition [Line Items]
Goodwill			$ 41,736,000
Number of Enstar ordinary shares issued (shares) | shares			2,007,017
Closing price of shares (dollars per share) | $ / shares			$ 206.65
Ownership percentage acquired			51.80%
Price-to-book multiple			1.05
Gain recognized on remeasurement of previously held equity method investment to fair value				$ 16,000,000	$ 16,007,000
Loss on settlement of preexisting relationships				$ 15,600,000	$ 15,600,000
Ordinary Shares | KaylaRe
Business Acquisition [Line Items]
Number of Enstar ordinary shares issued (shares) | shares			1,501,778
Series E non-voting convertible ordinary shares | KaylaRe
Business Acquisition [Line Items]
Number of Enstar ordinary shares issued (shares) | shares			505,239
KaylaRe
Business Acquisition [Line Items]
Ownership percentage								48.20%

Acquisitions - Summary of Estim

Acquisitions - Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed as of Date of Acquisition (Details) - USD ($) $ in Thousands	Oct. 30, 2019	Dec. 27, 2018	May 14, 2018
Morse TEC
ASSETS
Cash and cash equivalents	$ 171,412
Deferred tax assets	140,000
Other assets - Insurance balances recoverable	371,116
TOTAL ASSETS	682,528
LIABILITIES
Defendant asbestos and environmental liabilities	662,507
Other liabilities	20,021
TOTAL LIABILITIES	682,528
NET ASSETS ACQUIRED AT FAIR VALUE	$ 0
Maiden Re
ASSETS
Cash and cash equivalents		$ 12,035
Restricted cash and cash equivalents		26,871
Other assets		96,669
Premiums receivable		138,378
Prepaid reinsurance premiums		3,257
Reinsurance balances recoverable		87,018
TOTAL ASSETS		1,466,329
Fixed maturities, trading, at fair value		1,098,593
Short-term investments, trading, at fair value		3,508
Total investments		1,102,101
LIABILITIES
Unearned premiums		85,696
Other liabilities		56,618
Losses and LAE		1,027,367
TOTAL LIABILITIES		1,169,681
NET ASSETS ACQUIRED AT FAIR VALUE		$ 296,648
KaylaRe
ASSETS
Cash and cash equivalents			$ 5,657
Other assets			614
Premiums receivable			10,965
Deferred acquisition costs			275
TOTAL ASSETS			770,380
Fixed maturities, trading, at fair value			126,393
Short-term investments, trading, at fair value			626,476
Total investments			752,869
LIABILITIES
Unearned premiums			10,984
Other liabilities			9,004
Losses and LAE			4,059
Insurance and reinsurance balances payable			13
TOTAL LIABILITIES			24,060
NET ASSETS ACQUIRED AT FAIR VALUE			$ 746,320

Acquisitions - Results of Opera

Acquisitions - Results of Operations Of Acquiree (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Morse TEC
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net investment income	$ 488
General and administrative expenses	(1,459)
Other expenses	(1,512)
Earnings of acquiree since acquisition date	$ (2,483)
Maiden Re
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net investment income		$ 675
General and administrative expenses		(435)
Net unrealized gains		3,749
Earnings of acquiree since acquisition date		3,989
KaylaRe
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net investment income		3,096
General and administrative expenses		(2,164)
Net unrealized gains		(47,769)
Earnings of acquiree since acquisition date		(45,915)
Premiums earned		13,627
Incurred losses and LAE		(12,364)
Acquisition costs		(341)
Underwriting income		$ 922

Acquisitions - Purchase Price a

Acquisitions - Purchase Price and Fair Value of Assets Acquired (Details) $ / shares in Units, $ in Thousands	Dec. 27, 2018USD ($)	May 14, 2018USD ($)$ / sharesshares	Jun. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	May 13, 2018USD ($)	Dec. 31, 2017USD ($)
Purchase Price
Excess of purchase price over fair value of net assets acquired					$ 114,807	$ 114,807		$ 73,071
Fair Value of Previously Held Equity Method Investment
Carrying value of previously held equity method investment prior to the close of the transaction					$ 326,277	$ 204,507
Maiden Re
Purchase Price
Cash paid	$ 286,375
Adjustment for the fair value of preexisting relationships	10,273
Purchase price	296,648
Net assets acquired at fair value	296,648
Excess of purchase price over fair value of net assets acquired	$ 0
KaylaRe
Purchase Price
Adjustment for the fair value of preexisting relationships		$ 37,169
Value of ordinary shares issued		414,750
Fair value of previously held equity method investment		336,137
Purchase price		788,056
Net assets acquired at fair value		746,320
Excess of purchase price over fair value of net assets acquired		$ 41,736
Fair Value of Enstar Ordinary Shares Issued
Number of Enstar ordinary shares issued (shares) | shares		2,007,017
Closing price of shares (dollars per share) | $ / shares		$ 206.65
Fair value of Enstar ordinary shares issued to shareholders of KaylaRe		$ 414,750
Fair Value of Previously Held Equity Method Investment
Price-to-book multiple		1.05
Fair value of previously held equity method investment prior to the close of the transaction		$ 336,137
Gain recognized on remeasurement of previously held equity method investment to fair value			$ 16,000	$ 16,007
KaylaRe
Fair Value of Previously Held Equity Method Investment
Carrying value of previously held equity method investment prior to the close of the transaction							$ 320,130

Acquisitions - Supplemental Pro

Acquisitions - Supplemental Pro Forma Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Total income	$ 533,235	$ 511,395	$ 641,214	$ 887,267	$ 187,909	$ 291,980	$ 239,864	$ 103,782	$ 2,573,111	$ 823,535	$ 1,100,952
Total noncontrolling interest	$ 4,900	$ 109	$ 2,713	$ 2,148	$ 42,955	$ 11,489	$ 8,389	$ (782)	9,870	62,051	(20,341)
Net earnings (loss)									932,656	(218,396)	$ 314,411
Morse TEC
Business Acquisition [Line Items]
Total income									76,480	42,766
Total income, pro forma									2,705,013	908,448
Total expenses									(8,918)	(30,187)
Total expenses, pro forma									(1,708,261)	(1,108,141)
Total noncontrolling interest									0	0
Total noncontrolling interest, pro forma									9,870	62,051
Net earnings (loss)									67,562	12,579
Net earnings (loss), pro forma									1,006,622	(137,642)
Pro forma Adjustments
Business Acquisition [Line Items]
Total income									2,629,021	865,682
Total expenses									(1,700,802)	(1,077,954)
Total noncontrolling interest									9,870	62,051
Net earnings (loss)									938,089	$ (150,221)
Revenues Adjustment | Pro forma Adjustments | Morse TEC
Business Acquisition [Line Items]
Total income									(488)
Total expenses									1,459
Total noncontrolling interest									0
Net earnings (loss)									$ 971

Acquisitions - Summary of Pro F

Acquisitions - Summary of Pro Forma Adjustments (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Total income	$ 533,235	$ 511,395	$ 641,214	$ 887,267	$ 187,909	$ 291,980	$ 239,864	$ 103,782	$ 2,573,111	$ 823,535	$ 1,100,952
Pro forma Adjustments
Business Acquisition [Line Items]
Total income									2,629,021	865,682
Total expenses									1,700,802	1,077,954
Morse TEC
Business Acquisition [Line Items]
Total income									76,480	42,766
Total expenses									8,918	$ 30,187
Morse TEC | Pro forma Adjustments | Revenues Adjustment
Business Acquisition [Line Items]
Total income									(488)
Total expenses									$ (1,459)

Acquisitions - Loss on Settleme

Acquisitions - Loss on Settlement Of Contractual Preexisting Relationships (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	May 14, 2018	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Funds held by reinsured companies	$ 408,735	$ 321,267
Deferred acquisition costs/Value of business acquired	272,462	86,585		$ 80,192	$ 94,551
TOTAL ASSETS	19,363,315	16,556,270
LIABILITIES
Losses and LAE	10,429,238	9,409,504		$ 7,398,088	$ 5,987,867
Unearned premiums	746,775	842,618
Insurance and reinsurance balances payable	373,180	388,086
Other liabilities	464,014	468,129
TOTAL LIABILITIES	14,068,173	12,183,738
NET ASSETS (LIABILITIES)	$ 4,856,351	$ 3,913,989
Carrying value | KaylaRe
ASSETS
Funds held by reinsured companies			$ 386,793
Deferred acquisition costs/Value of business acquired			33,549
TOTAL ASSETS			420,342
LIABILITIES
Losses and LAE			339,747
Unearned premiums			105,602
Insurance and reinsurance balances payable			25,897
Other liabilities			1,864
TOTAL LIABILITIES			473,110
NET ASSETS (LIABILITIES)			(52,768)
Fair value | KaylaRe
ASSETS
Funds held by reinsured companies			386,793
Deferred acquisition costs/Value of business acquired			40,268
TOTAL ASSETS			427,061
LIABILITIES
Losses and LAE			333,205
Unearned premiums			105,602
Insurance and reinsurance balances payable			23,559
Other liabilities			1,864
TOTAL LIABILITIES			464,230
NET ASSETS (LIABILITIES)			(37,169)
Loss on deemed settlement | KaylaRe
ASSETS
Funds held by reinsured companies			0
Deferred acquisition costs/Value of business acquired			6,719
TOTAL ASSETS			6,719
LIABILITIES
Losses and LAE			(6,542)
Unearned premiums			0
Insurance and reinsurance balances payable			(2,338)
Other liabilities			0
TOTAL LIABILITIES			(8,880)
NET ASSETS (LIABILITIES)			$ 15,599

Significant New Business - 2020

Significant New Business - 2020 Significant Business (Details) - 6 months ended Jun. 30, 2020 - Scenario, Forecast $ in Millions, $ in Millions	AUD ($)	USD ($)
AXA Group
Schedule of Investments [Line Items]
Assumed business, net		$ 225
Munich Re
Schedule of Investments [Line Items]
Assumed business, net	$ 228.2	$ 160.3

Significant New Business - 2019

Significant New Business - 2019 Significant Business (Details) $ in Thousands, £ in Millions, $ in Millions	Oct. 01, 2019USD ($)	Aug. 05, 2019USD ($)	Apr. 11, 2019USD ($)	Feb. 14, 2019USD ($)Agreement	Feb. 14, 2019GBP (£)Agreement	Feb. 23, 2018AUD ($)	Feb. 23, 2018USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Schedule of Investments [Line Items]
Assumed business								$ 1,586,307	$ 1,772,104	$ 1,525,703
Deferred charge asset								$ 272,462	$ 86,585	$ 80,192	$ 94,551
Zurich
Schedule of Investments [Line Items]
Assumed business	$ 622,900					$ 359.4	$ 280,800
Reinsurance premium consideration	465,500					$ 343.9	$ 268,700
Deferred charge asset	$ 115,800
Maiden Re Bermuda
Schedule of Investments [Line Items]
Assumed business		$ 530,200
Reinsurance premium consideration		445,000
Deferred charge asset		85,200
Amerisure
Schedule of Investments [Line Items]
Assumed business			$ 48,300
Reinsurance premium consideration			45,500
Deferred charge asset			$ 2,900
Percentage of quota share assumed			50.00%
AmTrust RITC
Schedule of Investments [Line Items]
Assumed business				$ 897,100	£ 703.8
Deferred charge asset				$ 20,600
Number of quota share agreements | Agreement				4	4
Assumed business, net				$ 620,400	£ 486.8
Cash consideration				$ 688,200	£ 539.9
Minimum | Maiden Re Bermuda
Schedule of Investments [Line Items]
Assumed business		2,200,000
Maximum | Maiden Re Bermuda
Schedule of Investments [Line Items]
Assumed business		$ 600,000
Zurich | EnhanzedRe
Schedule of Investments [Line Items]
Percentage ceded								10.00%

Significant New Business - 2018

Significant New Business - 2018 Significant Business (Details) $ in Thousands, £ in Millions, $ in Millions	Oct. 01, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 27, 2018USD ($)	Aug. 01, 2018USD ($)	Feb. 23, 2018AUD ($)	Feb. 23, 2018USD ($)	Feb. 16, 2018USD ($)	Feb. 16, 2018GBP (£)	Jan. 29, 2018USD ($)	Jan. 29, 2018GBP (£)	Dec. 28, 2017USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Feb. 23, 2018USD ($)	Dec. 31, 2016USD ($)
Schedule of Investments [Line Items]
Assumed business												$ 1,586,307	$ 1,772,104	$ 1,525,703
Funds held by reinsured companies		$ 321,267										408,735	321,267
Deferred charge		86,585										$ 272,462	$ 86,585	$ 80,192		$ 94,551
Allianz
Schedule of Investments [Line Items]
Reinsurance premium consideration		$ 70,000
Funds held by reinsured companies											$ 81,400
Assumed business, net											$ 81,400
Maiden Re North America
Schedule of Investments [Line Items]
Assumed business			$ 72,100
Funds held by reinsured companies			70,400
Deferred charge			$ 1,700
Coca-Cola
Schedule of Investments [Line Items]
Assumed business				$ 120,800
Deferred charge				17,200
Cash consideration				$ 103,600
Zurich
Schedule of Investments [Line Items]
Reinsurance premium consideration	$ 465,500				$ 343.9	$ 268,700
Assumed business	$ 622,900				359.4	$ 280,800
Fair value adjustment on gross reserves					$ 15.5										$ 12,100
Neon
Schedule of Investments [Line Items]
Reinsurance premium consideration							$ 445,100	£ 329.1
Assumed business							546,300	403.9
Fair value adjustment on gross reserves							20,600
Assumed business, net							462,600	£ 342.1
Fair value adjustment on net reserves							$ 17,500
Novae Transaction
Schedule of Investments [Line Items]
Reinsurance premium consideration									$ 803,500	£ 594.1
Assumed business									1,163,200	860.1
Fair value adjustment on gross reserves									67,500
Assumed business, net									853,000	£ 630.7
Fair value adjustment on net reserves									$ 49,500

Significant New Business - 2017

Significant New Business - 2017 Significant Business (Details) $ in Thousands, £ in Millions	Dec. 28, 2017USD ($)	Feb. 07, 2017USD ($)	Feb. 07, 2017GBP (£)	Jan. 11, 2017USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Feb. 07, 2017GBP (£)
Schedule of Investments [Line Items]
Funds held by reinsured companies					$ 408,735	$ 321,267
Assumed business					$ 1,586,307	$ 1,772,104	$ 1,525,703
Allianz
Schedule of Investments [Line Items]
Percentage of reinsurance agreements entered	50.00%
Assumed business, net	$ 81,400
Funds held by reinsured companies	81,400
Funds transferred to a reinsurance trust	8,100
Funds held by reinsured companies	$ 162,800
RSA
Schedule of Investments [Line Items]
Assumed business, net		$ 1,153,900	£ 927.5
Assumed business		1,301,800	£ 1,046.4
Reinsurance premium receivable		997,200						£ 801.6
Fair value adjustment on gross reserves		174,100
Fair value adjustment on net reserves		$ 156,700
QBE
Schedule of Investments [Line Items]
Assumed business, net				$ 447,000
Assumed business				1,019,000
Reinsurance premium receivable				403,800
Fair value adjustment on gross reserves				180,000
Fair value adjustment on net reserves				43,200
Restricted cash				227,600
Funds held				$ 176,200

Divestitures, Held-For-Sale B_2

Divestitures, Held-For-Sale Businesses and Discontinued Operations - Additional Information (Details) $ in Thousands, € in Millions	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 29, 2017USD ($)	Aug. 29, 2017USD ($)	Aug. 29, 2017EUR (€)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Policy benefits for life contracts		$ 105,100
Net earnings from discontinued operations, net of income taxes	$ 0	0	$ 10,993
Loss on sale of subsidiary	0	0	16,349
Cumulative CTA adjustment	0	0	20,751
Pavonia | Discontinued operations, disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received				$ 120,000
Net earnings from discontinued operations, net of income taxes			11,000
Pavonia | Discontinued operations, held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Change in cash of businesses held for sale			118,300
Cash, cash equivalents and restricted cash and cash equivalents				$ 135,100
Pavonia Life Insurance Company Of New York | Discontinued operations, held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	20,600	24,000
Liabilities held for sale	$ 11,700	$ 11,300
Laguna | Not discontinued operations, disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net earnings from discontinued operations, net of income taxes			(1,200)
Loss on sale of subsidiary			16,300
Cumulative CTA adjustment			$ 6,300
Monument | Affiliated entity | Laguna | Not discontinued operations, disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received					$ 30,800	€ 25.6

Investments - Asset Types (Deta

Investments - Asset Types (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	$ 2,041,724	$ 151,609
Total investments	9,612,888	8,697,892
U.S. government and agency
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	410,312	573
Total investments	736,043	510,245
U.K. government
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	15,349
Total investments	161,772	300,631
Other government
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	85,147	73,185
Total investments	702,857	793,810
Corporate
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	1,081,171	75,359
Total investments	5,697,067	4,839,840
Municipal
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	15,872	2,480
Total investments	167,882	130,265
Residential mortgage-backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	127,219	12
Total investments	471,836	773,557
Commercial mortgage-backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	98,557
Total investments	900,029	713,063
Asset-backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	208,097
Total investments	775,402	636,481
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	356,900	656,600
Senior Secured Debt Securities
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	31,400	20,400
Short-term Investments
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	51,490	114,116
Debt securities, available-for-sale	128,335	0
Short-term Investments | U.S. government and agency
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	0	45,885
Debt securities, available-for-sale	111,583
Short-term Investments | U.K. government
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	24,411	2,275
Debt securities, available-for-sale	1,069
Short-term Investments | Other government
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	21,958	19,064
Debt securities, available-for-sale	387
Short-term Investments | Corporate
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	5,121	44,900
Debt securities, available-for-sale	13,915
Short-term Investments | Municipal
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	0	0
Debt securities, available-for-sale	1,381
Short-term Investments | Residential mortgage-backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	0	0
Debt securities, available-for-sale	0
Short-term Investments | Commercial mortgage-backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	0	0
Debt securities, available-for-sale	0
Short-term Investments | Asset-backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	0	1,992
Debt securities, available-for-sale	0
Fixed Maturities
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	6,346,329	7,248,793
Debt securities, available-for-sale	1,913,389	151,609
Fixed Maturities | U.S. government and agency
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	219,194	389,735
Debt securities, available-for-sale	298,729	573
Fixed Maturities | U.K. government
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	122,012	298,356
Debt securities, available-for-sale	14,280	0
Fixed Maturities | Other government
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	575,018	679,525
Debt securities, available-for-sale	84,760	73,185
Fixed Maturities | Corporate
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	4,007,386	4,081,793
Debt securities, available-for-sale	1,067,256	75,359
Fixed Maturities | Municipal
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	102,554	73,856
Debt securities, available-for-sale	14,491	2,480
Fixed Maturities | Residential mortgage-backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	258,412	682,962
Debt securities, available-for-sale	127,219	12
Fixed Maturities | Commercial mortgage-backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	571,129	488,598
Debt securities, available-for-sale	98,557	0
Fixed Maturities | Asset-backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	490,624	553,968
Debt securities, available-for-sale	208,097	0
Funds Held - Directly Managed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	1,173,345	1,183,374
Funds Held - Directly Managed | U.S. government and agency
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	106,537	74,052
Funds Held - Directly Managed | U.K. government
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	0	0
Funds Held - Directly Managed | Other government
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	20,734	22,036
Funds Held - Directly Managed | Corporate
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	603,389	637,788
Funds Held - Directly Managed | Municipal
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	49,456	53,929
Funds Held - Directly Managed | Residential mortgage-backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	86,205	90,583
Funds Held - Directly Managed | Commercial mortgage-backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	230,343	224,465
Funds Held - Directly Managed | Asset-backed
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	$ 76,681	$ 80,521

Investments - Contractual Matur

Investments - Contractual Maturities (Details) - Short-term investments and fixed maturities $ in Thousands	Dec. 31, 2019USD ($)
Amortized Cost
One year or less	$ 537,944
More than one year through two years	801,473
More than two years through five years	2,175,547
More than five years through ten years	2,108,172
More than ten years	1,584,345
Fixed maturity investments, at amortized cost	9,336,295
Fair Value
One year or less	536,156
More than one year through two years	808,071
More than two years through five years	2,212,834
More than five years through ten years	2,198,505
More than ten years	1,710,055
Trading securities, debt	$ 9,612,888
% of Total Fair Value
One year or less	5.60%
More than one year through two years	8.40%
More than two years through five years	23.00%
More than five years through ten years	22.90%
More than ten years	17.80%
Trading securities, percentage of fair value	100.00%
Residential mortgage-backed
Amortized Cost
Securities without single maturity date	$ 466,932
Fair Value
Securities without single maturity date	$ 471,836
% of Total Fair Value
Securities without single maturity date	4.90%
Commercial mortgage-backed
Amortized Cost
Securities without single maturity date	$ 882,603
Fair Value
Securities without single maturity date	$ 900,029
% of Total Fair Value
Securities without single maturity date	9.40%
Asset-backed
Amortized Cost
Securities without single maturity date	$ 779,279
Fair Value
Securities without single maturity date	$ 775,402
% of Total Fair Value
Securities without single maturity date	8.00%

Investments - Credit Ratings (D

Investments - Credit Ratings (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 9,336,295
Fair Value	9,612,888
Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 391,947
Marketable Securities | Portfolio Concentration Risk | Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	100.00%
Trading and Available for Sale Securities | Credit Rating Concentration Risk | Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	4.10%
AAA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 2,609,762
AAA Rated | Trading and Available for Sale Securities | Credit Rating Concentration Risk | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	27.10%
AA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,239,096
AA Rated | Trading and Available for Sale Securities | Credit Rating Concentration Risk | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	12.90%
A Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 3,297,996
A Rated | Trading and Available for Sale Securities | Credit Rating Concentration Risk | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	34.30%
BBB Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 2,056,887
BBB Rated | Trading and Available for Sale Securities | Credit Rating Concentration Risk | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	21.40%
Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 17,200
Not Rated | Trading and Available for Sale Securities | Credit Rating Concentration Risk
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	0.20%
U.S. government and agency
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 730,396
Fair Value	736,043
U.S. government and agency | Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 0
U.S. government and agency | Marketable Securities | Portfolio Concentration Risk | Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	7.70%
U.S. government and agency | AAA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 736,043
U.S. government and agency | AA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
U.S. government and agency | A Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
U.S. government and agency | BBB Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
U.S. government and agency | Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
U.K. government
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	155,261
Fair Value	161,772
U.K. government | Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 0
U.K. government | Marketable Securities | Portfolio Concentration Risk | Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	1.70%
U.K. government | AAA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 0
U.K. government | AA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	161,772
U.K. government | A Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
U.K. government | BBB Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
U.K. government | Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
Other government
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	684,117
Fair Value	702,857
Other government | Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 24,807
Other government | Marketable Securities | Portfolio Concentration Risk | Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	7.30%
Other government | AAA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 316,151
Other government | AA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	154,072
Other government | A Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	63,270
Other government | BBB Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	144,557
Other government | Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
Corporate
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	5,479,839
Fair Value	5,697,067
Corporate | Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 311,167
Corporate | Marketable Securities | Portfolio Concentration Risk | Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	59.20%
Corporate | AAA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 149,108
Corporate | AA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	619,707
Corporate | A Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	2,911,867
Corporate | BBB Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	1,703,328
Corporate | Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	1,890
Municipal
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	157,868
Fair Value	167,882
Municipal | Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 0
Municipal | Marketable Securities | Portfolio Concentration Risk | Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	1.70%
Municipal | AAA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 16,381
Municipal | AA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	77,291
Municipal | A Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	50,938
Municipal | BBB Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	23,272
Municipal | Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	0
Residential mortgage-backed
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	466,932
Fair Value	471,836
Residential mortgage-backed | Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 34,055
Residential mortgage-backed | Marketable Securities | Portfolio Concentration Risk | Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	4.90%
Residential mortgage-backed | AAA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 381,502
Residential mortgage-backed | AA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	47,489
Residential mortgage-backed | A Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	2,295
Residential mortgage-backed | BBB Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	1,882
Residential mortgage-backed | Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	4,613
Commercial mortgage-backed
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	882,603
Fair Value	900,029
Commercial mortgage-backed | Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 6,224
Commercial mortgage-backed | Marketable Securities | Portfolio Concentration Risk | Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	9.40%
Commercial mortgage-backed | AAA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 632,461
Commercial mortgage-backed | AA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	89,347
Commercial mortgage-backed | A Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	95,508
Commercial mortgage-backed | BBB Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	66,573
Commercial mortgage-backed | Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	9,916
Asset-backed
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	779,279
Fair Value	775,402
Asset-backed | Non-Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 15,694
Asset-backed | Marketable Securities | Portfolio Concentration Risk | Trading Securities and Available for Sale Securities
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Percent of total investments	8.10%
Asset-backed | AAA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 378,116
Asset-backed | AA Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	89,418
Asset-backed | A Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	174,118
Asset-backed | BBB Rated | Investment Grade
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	117,275
Asset-backed | Not Rated
Schedule of Trading Securities and Available-for-sale Securities [Line Items]
Amortized Cost	$ 781

Investments - Available-for-sal

Investments - Available-for-sale Portfolio (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 2,042,454	$ 151,433
Gross Unrealized Gains	5,971	2,225
Gross Unrealized Losses Non-OTTI	(6,701)	(2,049)
Fair Value	2,041,724	151,609
U.S. government and agency
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	410,842	576
Gross Unrealized Gains	77	0
Gross Unrealized Losses Non-OTTI	(607)	(3)
Fair Value	410,312	573
U.K. government
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	15,067
Gross Unrealized Gains	282
Gross Unrealized Losses Non-OTTI	0
Fair Value	15,349
Other government
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	84,116	72,811
Gross Unrealized Gains	1,119	1,219
Gross Unrealized Losses Non-OTTI	(88)	(845)
Fair Value	85,147	73,185
Corporate
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,081,713	75,535
Gross Unrealized Gains	4,026	1,006
Gross Unrealized Losses Non-OTTI	(4,568)	(1,182)
Fair Value	1,081,171	75,359
Municipal
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	15,963	2,499
Gross Unrealized Gains	20	0
Gross Unrealized Losses Non-OTTI	(111)	(19)
Fair Value	15,872	2,480
Residential mortgage-backed
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	127,704	12
Gross Unrealized Gains	240	0
Gross Unrealized Losses Non-OTTI	(725)	0
Fair Value	127,219	$ 12
Commercial mortgage-backed
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	98,928
Gross Unrealized Gains	38
Gross Unrealized Losses Non-OTTI	(409)
Fair Value	98,557
Asset-backed
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	208,121
Gross Unrealized Gains	169
Gross Unrealized Losses Non-OTTI	(193)
Fair Value	$ 208,097

Investments - Gross Unrealized

Investments - Gross Unrealized Losses (Details) $ in Thousands	Dec. 31, 2019USD ($)Security	Dec. 31, 2018USD ($)Security
Fair Value
12 Months or Greater	$ 3,962	$ 21,607
Less Than 12 Months	1,008,869	36,510
Total	1,012,831	58,117
Gross Unrealized Losses
12 Months or Greater	(329)	(995)
Less Than 12 Months	(6,372)	(1,054)
Total	$ (6,701)	$ (2,049)
Number of securities in unrealized loss position | Security	563	88
Number of securities in unrealized loss position, twelve months or longer | Security	12	42
U.S. government and agency
Fair Value
12 Months or Greater	$ 0	$ 573
Less Than 12 Months	222,643	0
Total	222,643	573
Gross Unrealized Losses
12 Months or Greater	0	(3)
Less Than 12 Months	(607)	0
Total	(607)	(3)
Other government
Fair Value
12 Months or Greater	1,080	7,351
Less Than 12 Months	37,796	11,000
Total	38,876	18,351
Gross Unrealized Losses
12 Months or Greater	(23)	(345)
Less Than 12 Months	(65)	(500)
Total	(88)	(845)
Corporate
Fair Value
12 Months or Greater	2,754	11,888
Less Than 12 Months	461,772	25,227
Total	464,526	37,115
Gross Unrealized Losses
12 Months or Greater	(306)	(629)
Less Than 12 Months	(4,262)	(553)
Total	(4,568)	(1,182)
Municipal
Fair Value
12 Months or Greater	128	1,783
Less Than 12 Months	12,046	283
Total	12,174	2,066
Gross Unrealized Losses
12 Months or Greater	0	(18)
Less Than 12 Months	(111)	(1)
Total	(111)	(19)
Residential mortgage-backed
Fair Value
12 Months or Greater	0	12
Less Than 12 Months	65,992	0
Total	65,992	12
Gross Unrealized Losses
12 Months or Greater	0	0
Less Than 12 Months	(725)	0
Total	(725)	$ 0
Commercial mortgage-backed
Fair Value
12 Months or Greater	0
Less Than 12 Months	79,606
Total	79,606
Gross Unrealized Losses
12 Months or Greater	0
Less Than 12 Months	(409)
Total	(409)
Asset-backed
Fair Value
12 Months or Greater	0
Less Than 12 Months	129,014
Total	129,014
Gross Unrealized Losses
12 Months or Greater	0
Less Than 12 Months	(193)
Total	$ (193)

Investments - Other Than Tempor

Investments - Other Than Temporary Impairment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Other than temporary impairment losses, available-for-sale securities	$ 0	$ 0	$ 0
Available-for-sale securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Credit losses	$ 0	$ 0

Investments - Equity Securities

Investments - Equity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Investment [Line Items]
Equity investments	$ 729,721	$ 367,125
Publicly traded equity investments in common and preferred stocks
Investment [Line Items]
Equity investments	327,875	138,415
Exchange-traded funds
Investment [Line Items]
Equity investments	133,047	0
Privately held equity investments in common and preferred stocks
Investment [Line Items]
Equity investments	268,799	$ 228,710
AmTrust Financial Services, Inc.
Investment [Line Items]
Indirect investment	$ 240,100

Investments - Other Investments

Investments - Other Investments, at Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Investments [Line Items]
Other investments, at fair value	$ 2,524,420	$ 1,957,757
Valuation lag period	3 months
Net additional subscriptions	$ 796,918	901,071	$ 109,885
Hedge funds
Other Investments [Line Items]
Other investments, at fair value	1,121,904	852,584
Fixed income funds
Other Investments [Line Items]
Other investments, at fair value	481,039	403,858
Equity funds
Other Investments [Line Items]
Other investments, at fair value	410,149	333,681
Private equity funds
Other Investments [Line Items]
Other investments, at fair value	329,885	248,628
Unfunded commitments	482,300
CLO equity funds
Other Investments [Line Items]
Other investments, at fair value	87,509	37,260
CLO equities
Other Investments [Line Items]
Other investments, at fair value	87,555	39,052
Private credit funds
Other Investments [Line Items]
Other investments, at fair value	0	33,381
Other
Other Investments [Line Items]
Other investments, at fair value	6,379	9,313
Other investments
Other Investments [Line Items]
Unrealized gains	441,636	$ (163,976)	$ 102,388
Net additional subscriptions	214,300
Less than 1 Year
Other Investments [Line Items]
Other investments, at fair value	1,379,413
Less than 1 Year | Hedge funds
Other Investments [Line Items]
Other investments, at fair value	343,005
Less than 1 Year | Fixed income funds
Other Investments [Line Items]
Other investments, at fair value	477,935
Less than 1 Year | Equity funds
Other Investments [Line Items]
Other investments, at fair value	410,149
Less than 1 Year | Private equity funds
Other Investments [Line Items]
Other investments, at fair value
Less than 1 Year | CLO equity funds
Other Investments [Line Items]
Other investments, at fair value	60,735
Less than 1 Year | CLO equities
Other Investments [Line Items]
Other investments, at fair value	87,555
Less than 1 Year | Other
Other Investments [Line Items]
Other investments, at fair value	34
1-2 years
Other Investments [Line Items]
Other investments, at fair value	624,233
1-2 years | Hedge funds
Other Investments [Line Items]
Other investments, at fair value	624,233
1-2 years | Fixed income funds
Other Investments [Line Items]
Other investments, at fair value	0
1-2 years | Equity funds
Other Investments [Line Items]
Other investments, at fair value	0
1-2 years | Private equity funds
Other Investments [Line Items]
Other investments, at fair value	0
1-2 years | CLO equity funds
Other Investments [Line Items]
Other investments, at fair value	0
1-2 years | CLO equities
Other Investments [Line Items]
Other investments, at fair value	0
1-2 years | Other
Other Investments [Line Items]
Other investments, at fair value	0
2-3 years
Other Investments [Line Items]
Other investments, at fair value	26,774
2-3 years | Hedge funds
Other Investments [Line Items]
Other investments, at fair value	0
2-3 years | Fixed income funds
Other Investments [Line Items]
Other investments, at fair value	0
2-3 years | Equity funds
Other Investments [Line Items]
Other investments, at fair value	0
2-3 years | Private equity funds
Other Investments [Line Items]
Other investments, at fair value	0
2-3 years | CLO equity funds
Other Investments [Line Items]
Other investments, at fair value	26,774
2-3 years | CLO equities
Other Investments [Line Items]
Other investments, at fair value	0
2-3 years | Other
Other Investments [Line Items]
Other investments, at fair value	0
More than 3 years
Other Investments [Line Items]
Other investments, at fair value	102,600
More than 3 years | Hedge funds
Other Investments [Line Items]
Other investments, at fair value	102,600
More than 3 years | Fixed income funds
Other Investments [Line Items]
Other investments, at fair value	0
More than 3 years | Equity funds
Other Investments [Line Items]
Other investments, at fair value	0
More than 3 years | Private equity funds
Other Investments [Line Items]
Other investments, at fair value	0
More than 3 years | CLO equity funds
Other Investments [Line Items]
Other investments, at fair value	0
More than 3 years | CLO equities
Other Investments [Line Items]
Other investments, at fair value	0
More than 3 years | Other
Other Investments [Line Items]
Other investments, at fair value	0
Not Eligible/ Restricted
Other Investments [Line Items]
Other investments, at fair value	391,400
Not Eligible/ Restricted | Hedge funds
Other Investments [Line Items]
Other investments, at fair value	52,066
Not Eligible/ Restricted | Fixed income funds
Other Investments [Line Items]
Other investments, at fair value	3,104
Not Eligible/ Restricted | Equity funds
Other Investments [Line Items]
Other investments, at fair value	0
Not Eligible/ Restricted | Private equity funds
Other Investments [Line Items]
Other investments, at fair value	329,885
Not Eligible/ Restricted | CLO equity funds
Other Investments [Line Items]
Other investments, at fair value	0
Not Eligible/ Restricted | CLO equities
Other Investments [Line Items]
Other investments, at fair value	0
Not Eligible/ Restricted | Other
Other Investments [Line Items]
Other investments, at fair value	$ 6,345

Investments - Equity Method Inv

Investments - Equity Method Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Investment	$ 266,823	$ 197,860
Ownership %	47.40%	47.40%
Equity method investments	$ 326,277	$ 204,507
EnhanzedRe
Schedule of Equity Method Investments [Line Items]
Investment	$ 154,050	$ 94,800
Ownership %	47.40%	47.40%
Equity method investments	$ 182,856	$ 94,800
Citco
Schedule of Equity Method Investments [Line Items]
Investment	$ 50,000	$ 50,000
Ownership %	31.90%	31.90%
Equity method investments	$ 51,742	$ 50,812
Monument
Schedule of Equity Method Investments [Line Items]
Investment	$ 26,600	$ 26,600
Ownership %	26.60%	26.60%
Equity method investments	$ 60,598	$ 42,193
Clear Spring
Schedule of Equity Method Investments [Line Items]
Investment	$ 11,210	$ 11,210
Ownership %	20.00%	20.00%
Equity method investments	$ 10,645	$ 10,070
Other
Schedule of Equity Method Investments [Line Items]
Investment	$ 24,963	$ 15,250
Ownership %	30.00%	30.00%
Equity method investments	$ 20,436	$ 6,632
Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Unfunded commitments	$ 93,100

Investments - Funds Held (Detai

Investments - Funds Held (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Funds Held, Directly Managed [Abstract]
Funds held - directly managed	$ 1,187,552	$ 1,198,154
Net unrealized gains (losses):
Funds held by reinsured companies	408,735	321,267
Funds held - Directly Managed - Fair Value Option
Funds Held, Directly Managed [Abstract]
Fixed maturity investments, trading	191,297	176,937
Funds Held, Directly Managed, Fixed-Maturity Investment Components [Abstract]
Fixed maturity investments, at amortized cost	185,859	179,670
Net unrealized gains (losses):
Change in fair value - fair value option accounting	5,438	(2,733)
Change in fair value - embedded derivative accounting	0	0
Fixed maturity investments, trading	191,297	176,937
Funds held - Directly Managed - Variable Return
Funds Held, Directly Managed [Abstract]
Fixed maturity investments, trading	982,048	1,006,437
Funds Held, Directly Managed, Fixed-Maturity Investment Components [Abstract]
Fixed maturity investments, at amortized cost	940,194	1,044,377
Net unrealized gains (losses):
Change in fair value - fair value option accounting	0	0
Change in fair value - embedded derivative accounting	41,854	(37,940)
Fixed maturity investments, trading	982,048	1,006,437
Funds Held - Directly Managed
Funds Held, Directly Managed [Abstract]
Fixed maturity investments, trading	1,173,345	1,183,374
Other assets	14,207	14,780
Funds held - directly managed	1,187,552	1,198,154
Funds Held, Directly Managed, Fixed-Maturity Investment Components [Abstract]
Fixed maturity investments, at amortized cost	1,126,053	1,224,047
Net unrealized gains (losses):
Change in fair value - fair value option accounting	5,438	(2,733)
Change in fair value - embedded derivative accounting	41,854	(37,940)
Fixed maturity investments, trading	$ 1,173,345	$ 1,183,374

Investments - Net Investment In

Investments - Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Investment Income [Line Items]
Gross investment income									$ 336,534	$ 280,392	$ 219,823
Investment expenses									(15,258)	(9,721)	(11,034)
Net investment income	$ 79,376	$ 85,472	$ 77,732	$ 78,696	$ 68,453	$ 69,430	$ 66,469	$ 66,319	321,276	270,671	208,789
Fixed maturity investments, trading
Net Investment Income [Line Items]
Gross investment income									233,310	189,000	144,367
Short-term investments and cash and cash equivalents
Net Investment Income [Line Items]
Gross investment income									16,607	12,117	9,314
Funds held
Net Investment Income [Line Items]
Gross investment income									19,981	10,041	601
Funds held – directly managed
Net Investment Income [Line Items]
Gross investment income									38,173	37,623	32,479
Investment income from fixed maturities and cash and cash equivalents
Net Investment Income [Line Items]
Gross investment income									308,071	248,781	186,761
Equity investments
Net Investment Income [Line Items]
Gross investment income									16,671	5,397	4,355
Other investments
Net Investment Income [Line Items]
Gross investment income									11,792	19,703	14,337
Life settlements and other
Net Investment Income [Line Items]
Gross investment income									0	6,511	14,370
Investment income from equities and other investments
Net Investment Income [Line Items]
Gross investment income									$ 28,463	$ 31,611	$ 33,062

Investments - Net Realized and

Investments - Net Realized and Unrealized Gains (Losses) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net realized gains (losses) on sale:
Total net realized gains (losses) on sale									$ 96,328	$ (27,633)	$ 1,668
Net unrealized gains (losses):
Fixed maturity securities, trading									349,975	(165,187)
Total net unrealized gains (losses)									935,023	(385,251)	188,666
Net realized gains (losses) and change in fair value of funds held- directly managed	$ 152,664	$ 148,185	$ 269,711	$ 460,791	$ (158,213)	$ (57,223)	$ (54,418)	$ (143,030)	1,031,351	(412,884)	190,334
Proceeds from sale of available from sale securities									310,400	11,400	40,800
Fixed maturity investments
Net realized gains (losses) on sale:
Gross realized gains on fixed maturity securities, available-for-sale securities									4,856	27	616
Gross realized losses on fixed maturity securities, available-for-sale securities									(962)	(90)	(125)
Net realized gains (losses) on trading securities									91,313	(27,646)	4,695
Net unrealized gains (losses):
Fixed maturity securities, trading											35,878
Funds Held - Directly Managed
Net realized gains (losses) on sale:
Net realized gains (losses) on trading securities									1,495	(3,940)	(4,219)
Net unrealized gains (losses):
Fixed maturity securities, trading									88,053	(46,257)
Fixed maturity securities, trading											33,902
Equity investments
Net realized gains (losses) on sale:
Net realized gains (losses) on equity investments, trading									(374)	4,016	701
Net unrealized gains (losses):
Equity investments, trading									55,359	(9,831)	16,498
Other investments
Net unrealized gains (losses):
Other investments									$ 441,636	$ (163,976)	$ 102,388

Investments - Restricted Assets

Investments - Restricted Assets (Details) $ in Thousands	Dec. 31, 2019USD ($)syndicate	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Investments, Debt and Equity Securities [Abstract]
Restricted cash and cash equivalents	$ 352,692	$ 380,488	$ 257,686
Line of Credit Facility [Line Items]
Collateral in trust for third party agreements	4,104,093	4,336,752
Assets on deposit with regulatory authorities	445,626	579,048
Funds at Lloyd's	639,316	354,589
Restricted assets, total	$ 5,322,273	5,398,230
Number of syndicates | syndicate	3
Asset Pledged as Collateral
Line of Credit Facility [Line Items]
Collateral for secured letter of credit facilities	$ 133,238	$ 127,841

Derivatives and Hedging Instr_3

Derivatives and Hedging Instruments - Foreign Currency Hedging (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effect of Net Investment Hedge
Currency translation gain (loss)	$ (2,428)	$ (202)	$ 30,174
Net Investment Hedging
Effect of Net Investment Hedge
Currency translation gain (loss)		3,144	(9,375)
Designated as Hedging Instrument | Foreign Exchange Forward
Gross Notional Amounts and Estimated Fair Values
Gross Notional Amount	495,291	108,680
Assets	642
Liabilities	11,452
Effect of Net Investment Hedge
Amount of Gains (Losses) Deferred in AOCI	(15,328)	4,438	(1,247)
Designated as Hedging Instrument | Foreign Exchange Forward | Australia, Dollars
Gross Notional Amounts and Estimated Fair Values
Gross Notional Amount	64,620	42,258
Assets	52	1,377
Liabilities	2,033	0
Effect of Net Investment Hedge
Amount of Gains (Losses) Deferred in AOCI	(722)	3,438	(1,247)
Designated as Hedging Instrument | Foreign Exchange Forward | Euro Member Countries, Euro
Gross Notional Amounts and Estimated Fair Values
Gross Notional Amount	112,284	66,422
Assets	246	238
Liabilities	1,635	300
Effect of Net Investment Hedge
Amount of Gains (Losses) Deferred in AOCI	1,817	1,000	0
Designated as Hedging Instrument | Foreign Exchange Forward | United Kingdom, Pounds
Gross Notional Amounts and Estimated Fair Values
Gross Notional Amount	318,387	0
Assets	344	0
Liabilities	7,784	0
Effect of Net Investment Hedge
Amount of Gains (Losses) Deferred in AOCI	$ (16,423)	$ 0	$ 0

Derivatives and Hedging Instr_4

Derivatives and Hedging Instruments - Foreign Currency Forward Contracts (Details) - Not Designated as Hedging Instrument - Foreign Exchange Forward - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Gross Notional Amount	$ 153,563	$ 411,718
Assets	1,369	5,086
Liabilities	4,106	683
Gains (losses) on non-qualifying hedges charged to earnings	13,207	31,643
Australia, Dollars
Derivative [Line Items]
Gross Notional Amount	913	45,427
Assets	839	1,952
Liabilities	892	310
Gains (losses) on non-qualifying hedges charged to earnings	1,523	4,958
Canada, Dollars
Derivative [Line Items]
Gross Notional Amount	66,266	55,050
Assets	10	1,441
Liabilities	1,482	0
Gains (losses) on non-qualifying hedges charged to earnings	(2,079)	9,311
Euro Member Countries, Euro
Derivative [Line Items]
Gross Notional Amount	74,444	54,282
Assets	507	139
Liabilities	1,440	301
Gains (losses) on non-qualifying hedges charged to earnings	1,759	2,296
United Kingdom, Pounds
Derivative [Line Items]
Gross Notional Amount	11,940	256,959
Assets	13	1,554
Liabilities	292	72
Gains (losses) on non-qualifying hedges charged to earnings	$ 12,004	$ 15,078

Derivatives and Hedging Instr_5

Derivatives and Hedging Instruments - Investments in Call Options (Details) - Not Designated as Hedging Instrument - Call options on equity - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Unrealized gains (losses) in net earnings	$ 500,000	$ (9,400,000)
Equities at cost	10,000,000	0
Fair value	$ 100,000	$ 600,000

Derivatives and Hedging Instr_6

Derivatives and Hedging Instruments - Other Derivatives (Details) - 12 months ended Dec. 31, 2019 - Interest Rate Swap $ in Millions, $ in Millions	USD ($)	AUD ($)	USD ($)
Derivative [Line Items]
Notional amount		$ 120
Unrealized gains (losses) in net earnings	$ (0.3)
Carrying value
Derivative [Line Items]
Derivative instruments			$ 0.3

Reinsurance Balances Recovera_3

Reinsurance Balances Recoverable on Paid and Unpaid Losses - Summary of Reinsurance Reserves Recoverable (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effects of Reinsurance [Line Items]
Outstanding losses	$ 1,309,313	$ 1,183,728
IBNR	903,749	830,465
Fair value adjustments - acquired companies	(15,255)	(15,613)
Fair value adjustments - fair value option	(88,086)	(130,739)
Total reinsurance reserves recoverable	2,109,721	1,867,841	$ 1,870,033	$ 1,388,193
Paid losses recoverable	270,169	161,822
Net	2,379,890	2,029,663
Reinsurance balances recoverable on paid and unpaid losses (Note 8)	1,684,372	1,290,072
Reinsurance balances recoverable on paid and unpaid losses - fair value option	695,518	739,591
Non-life Run-off
Effects of Reinsurance [Line Items]
Outstanding losses	972,293	901,772
IBNR	673,059	609,434
Fair value adjustments - acquired companies	(13,652)	(14,344)
Fair value adjustments - fair value option	(88,086)	(130,739)
Total reinsurance reserves recoverable	1,543,614	1,366,123	1,377,485	1,000,953
Paid losses recoverable	181,375	138,265
Net	1,724,989	1,504,388
Reinsurance balances recoverable on paid and unpaid losses (Note 8)	1,029,471	764,797
Reinsurance balances recoverable on paid and unpaid losses - fair value option	695,518	739,591
Atrium
Effects of Reinsurance [Line Items]
Outstanding losses	9,011	18,891
IBNR	19,286	19,247
Fair value adjustments - acquired companies	519	630
Fair value adjustments - fair value option	0	0
Total reinsurance reserves recoverable	28,816	38,768	40,531	30,009
Paid losses recoverable	1,541	(256)
Net	30,357	38,512
Reinsurance balances recoverable on paid and unpaid losses (Note 8)	30,357	38,512
Reinsurance balances recoverable on paid and unpaid losses - fair value option	0	0
StarStone
Effects of Reinsurance [Line Items]
Outstanding losses	328,009	263,065
IBNR	211,404	201,784
Fair value adjustments - acquired companies	(2,122)	(1,899)
Fair value adjustments - fair value option	0	0
Total reinsurance reserves recoverable	537,291	462,950	$ 452,017	$ 357,231
Paid losses recoverable	87,253	23,813
Net	624,544	486,763
Reinsurance balances recoverable on paid and unpaid losses (Note 8)	624,544	486,763
Reinsurance balances recoverable on paid and unpaid losses - fair value option	$ 0	$ 0

Reinsurance Balances Recovera_4

Reinsurance Balances Recoverable on Paid and Unpaid Losses - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effects of Reinsurance [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	$ 2,379,890	$ 2,379,890	$ 2,029,663
Increase in reinsurance recoverable		$ 350,243	$ 268,039	$ 530,857
Non-Life Run-Off
Effects of Reinsurance [Line Items]
Increase in reinsurance recoverable	$ 350,200

Reinsurance Balances Recovera_5

Reinsurance Balances Recoverable on Paid and Unpaid Losses - Top Ten Reinsurers (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)reinsurer	Dec. 31, 2018USD ($)reinsurer
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	$ 2,379,890	$ 2,029,663
Reinsurer concentration risk | Top Ten Reinsurers, Rated A Minus Or Higher
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	$ 1,292,207	$ 1,096,272
Number of external reinsurers | reinsurer	8	7
Reinsurer concentration risk | Top Ten Reinsurers, Non-Rated Reinsurers
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	$ 272,125	$ 316,238
Number of external reinsurers | reinsurer	2	3
Reinsurer concentration risk | Top Ten Reinsurers
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	$ 1,564,332	$ 1,412,510
Reinsurance balances recoverable | Reinsurer concentration risk
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	$ 2,379,890	$ 2,029,663
% of Total	100.00%	100.00%
Reinsurance balances recoverable | Reinsurer concentration risk | Top Ten Reinsurers
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	$ 1,564,332	$ 1,412,510
% of Total	65.70%	69.60%
Reinsurance balances recoverable | Reinsurer concentration risk | Other Reinsurers' Balances Greater Than $1 Million
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	$ 793,268	$ 596,312
% of Total	33.40%	29.40%
Reinsurance balances recoverable | Reinsurer concentration risk | Other Reinsurers' Balances Less Than $1 Million
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	$ 22,290	$ 20,841
% of Total	0.90%	1.00%
Non-life Run-off
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	$ 1,724,989	$ 1,504,388
Non-life Run-off | Reinsurance balances recoverable | Reinsurer concentration risk
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	1,724,989	1,504,388
Non-life Run-off | Reinsurance balances recoverable | Reinsurer concentration risk | Top Ten Reinsurers
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	1,154,110	1,124,079
Non-life Run-off | Reinsurance balances recoverable | Reinsurer concentration risk | Other Reinsurers' Balances Greater Than $1 Million
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	551,636	364,098
Non-life Run-off | Reinsurance balances recoverable | Reinsurer concentration risk | Other Reinsurers' Balances Less Than $1 Million
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	19,243	16,211
Atrium
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	30,357	38,512
Atrium | Reinsurance balances recoverable | Reinsurer concentration risk
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	30,357	38,512
Atrium | Reinsurance balances recoverable | Reinsurer concentration risk | Top Ten Reinsurers
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	22,051	25,239
Atrium | Reinsurance balances recoverable | Reinsurer concentration risk | Other Reinsurers' Balances Greater Than $1 Million
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	7,761	12,091
Atrium | Reinsurance balances recoverable | Reinsurer concentration risk | Other Reinsurers' Balances Less Than $1 Million
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	545	1,182
StarStone
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	624,544	486,763
StarStone | Reinsurance balances recoverable | Reinsurer concentration risk
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	624,544	486,763
StarStone | Reinsurance balances recoverable | Reinsurer concentration risk | Top Ten Reinsurers
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	388,171	263,192
StarStone | Reinsurance balances recoverable | Reinsurer concentration risk | Other Reinsurers' Balances Greater Than $1 Million
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	233,871	220,123
StarStone | Reinsurance balances recoverable | Reinsurer concentration risk | Other Reinsurers' Balances Less Than $1 Million
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	2,502	3,448
Equity method investee | Reinsurer concentration risk | Hannover Ruck SE
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	261,295	279,723
Equity method investee | Reinsurer concentration risk | Lloyd's Syndicate
Ceded Credit Risk [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	$ 411,030	$ 334,509

Reinsurance Balances Recovera_6

Reinsurance Balances Recoverable on Paid and Unpaid Losses - Provisions for Uncollectible Reinsurance Balances Recoverable by Rating of Reinsurer (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Effects of Reinsurance [Line Items]
Gross	$ 2,527,529	$ 2,186,395
Provisions for Bad Debt	147,639	156,732
Net	$ 2,379,890	$ 2,029,663
Provisions as a % of Gross	5.80%	7.20%
Reinsurers rated A- or above
Effects of Reinsurance [Line Items]
Gross	$ 1,904,268	$ 1,612,464
Provisions for Bad Debt	43,427	51,519
Net	$ 1,860,841	$ 1,560,945
Provisions as a % of Gross	2.30%	3.20%
Secured | Reinsurers Rated Below A-
Effects of Reinsurance [Line Items]
Gross	$ 487,608	$ 430,852
Provisions for Bad Debt	0	0
Net	$ 487,608	$ 430,852
Provisions as a % of Gross	0.00%	0.00%
Unsecured | Reinsurers Rated Below A-
Effects of Reinsurance [Line Items]
Gross	$ 135,653	$ 143,079
Provisions for Bad Debt	104,212	105,213
Net	$ 31,441	$ 37,866
Provisions as a % of Gross	76.80%	73.50%

Deferred Charge Assets (Details

Deferred Charge Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning carrying value	$ 86,585,000	$ 80,192,000	$ 94,551,000
Recorded during the year	224,504,000	20,174,000	0
Amortization	(38,627,000)	(13,781,000)	(14,359,000)
Ending carrying value	272,462,000	$ 86,585,000	$ 80,192,000
Impairment	$ 0

Losses and Loss Adjustment Ex_3

Losses and Loss Adjustment Expenses - Total Losses and Loss Adjustment Expense Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Outstanding losses	$ 5,394,529	$ 5,168,900
IBNR	5,057,868	4,468,991
Fair value adjustments - acquired companies	(167,511)	(214,518)
Fair value adjustments - fair value option	(217,933)	(374,752)
ULAE	362,285	360,883
Total gross liability for unpaid losses and LAE	10,429,238	9,409,504	$ 7,398,088	$ 5,987,867
Losses and loss adjustment expenses	7,808,116	6,535,449
Losses and loss adjustment expenses, fair value (Note 10 and Note 12)	2,621,122	2,874,055
Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Outstanding losses	4,407,082	4,271,769
IBNR	3,945,407	3,527,767
Fair value adjustments - acquired companies	(170,689)	(217,527)
Fair value adjustments - fair value option	(217,933)	(374,752)
ULAE	331,494	333,405
Total gross liability for unpaid losses and LAE	8,295,361	7,540,662	5,949,472	4,716,363
Atrium
Liability for Claims and Claims Adjustment Expense [Line Items]
Outstanding losses	89,141	94,885
IBNR	136,543	140,521
Fair value adjustments - acquired companies	3,700	3,476
ULAE	2,288	2,402
Total gross liability for unpaid losses and LAE	231,672	241,284	240,873	212,122
StarStone
Liability for Claims and Claims Adjustment Expense [Line Items]
Outstanding losses	888,794	796,194
IBNR	962,353	787,894
Fair value adjustments - acquired companies	(522)	(467)
ULAE	28,503	25,076
Total gross liability for unpaid losses and LAE	1,879,128	1,608,697	$ 1,207,743	$ 1,059,382
Operating Segments | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Outstanding losses	4,407,082	4,271,769
IBNR	3,945,407	3,527,767
Fair value adjustments - acquired companies	(170,689)	(217,527)
Fair value adjustments - fair value option	(217,933)	(374,752)
ULAE	331,494	333,405
Total gross liability for unpaid losses and LAE	8,295,361	7,540,662
Losses and loss adjustment expenses	5,674,239	4,666,607
Losses and loss adjustment expenses, fair value (Note 10 and Note 12)	2,621,122	2,874,055
Operating Segments | Atrium
Liability for Claims and Claims Adjustment Expense [Line Items]
Outstanding losses	89,141	94,885
IBNR	136,543	140,521
Fair value adjustments - acquired companies	3,700	3,476
Fair value adjustments - fair value option	0	0
ULAE	2,288	2,402
Total gross liability for unpaid losses and LAE	231,672	241,284
Losses and loss adjustment expenses	231,672	241,284
Losses and loss adjustment expenses, fair value (Note 10 and Note 12)	0	0
Operating Segments | StarStone
Liability for Claims and Claims Adjustment Expense [Line Items]
Outstanding losses	888,794	796,194
IBNR	962,353	787,894
Fair value adjustments - acquired companies	(522)	(467)
Fair value adjustments - fair value option	0	0
ULAE	28,503	25,076
Total gross liability for unpaid losses and LAE	1,879,128	1,608,697
Losses and loss adjustment expenses	1,879,128	1,608,697
Losses and loss adjustment expenses, fair value (Note 10 and Note 12)	0	0
Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Outstanding losses	9,512	6,052
IBNR	13,565	12,809
Fair value adjustments - acquired companies	0	0
Fair value adjustments - fair value option	0	0
ULAE	0	0
Total gross liability for unpaid losses and LAE	23,077	18,861
Losses and loss adjustment expenses	23,077	18,861
Losses and loss adjustment expenses, fair value (Note 10 and Note 12)	$ 0	$ 0

Losses and Loss Adjustment Ex_4

Losses and Loss Adjustment Expenses - Reconciliation of Beginning and Ending Reserves for Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance as at January 1				$ 9,409,504				$ 7,398,088	$ 9,409,504	$ 7,398,088	$ 5,987,867
Less: reinsurance reserves recoverable				1,867,841				1,870,033	1,867,841	1,870,033	1,388,193
Less: deferred charges on retroactive reinsurance				86,585				80,192	86,585	80,192	94,551
Net balance as at January 1				7,455,078				5,447,863	7,455,078	5,447,863	4,505,123
Net incurred losses and LAE:
Current period									823,658	689,782	437,853
Prior periods									48,917	(235,757)	(244,302)
Total net incurred losses and LAE	$ 121,416	$ 222,417	$ 216,338	312,404	$ 187,698	$ 153,974	$ 92,819	19,534	872,575	454,025	193,551
Net paid losses:
Current period									(200,264)	(189,560)	(82,273)
Prior periods									(1,669,004)	(1,194,985)	(862,921)
Total net paid losses									(1,869,268)	(1,384,545)	(945,194)
Effect of exchange rate movement									48,695	(145,243)	158,429
Acquired on purchase of subsidiaries									686	1,310,874	10,251
Assumed business									1,586,307	1,772,104	1,525,703
Ceded business									(47,018)	0	0
Net balance as at December 31	8,047,055				7,455,078				8,047,055	7,455,078	5,447,863
Plus: reinsurance reserves recoverable	2,109,721				1,867,841				2,109,721	1,867,841	1,870,033
Plus: deferred charges on retroactive reinsurance	272,462				86,585				272,462	86,585	80,192
Balance as at December 31	10,429,238				9,409,504				10,429,238	9,409,504	7,398,088
Non-life Run-off
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance as at January 1				7,540,662				5,949,472	7,540,662	5,949,472	4,716,363
Less: reinsurance reserves recoverable				1,366,123				1,377,485	1,366,123	1,377,485	1,000,953
Less: deferred charges on retroactive reinsurance				86,585				80,192	86,585	80,192	94,551
Net balance as at January 1				6,087,954				4,491,795	6,087,954	4,491,795	3,620,859
Net incurred losses and LAE:
Current period									123,559	12,451	5,866
Prior periods									(71,934)	(318,518)	(196,540)
Total net incurred losses and LAE									51,625	(306,067)	(190,674)
Net paid losses:
Current period									(64,820)	(5)	(2,835)
Prior periods									(1,182,804)	(838,812)	(578,888)
Total net paid losses									(1,247,624)	(838,817)	(581,723)
Effect of exchange rate movement									47,355	(132,632)	138,772
Acquired on purchase of subsidiaries									686	1,111,839	10,251
Assumed business									1,586,307	1,761,836	1,494,310
Ceded business									(47,018)	0	0
Net balance as at December 31	6,479,285				6,087,954				6,479,285	6,087,954	4,491,795
Plus: reinsurance reserves recoverable	1,543,614				1,366,123				1,543,614	1,366,123	1,377,485
Plus: deferred charges on retroactive reinsurance	272,462				86,585				272,462	86,585	80,192
Balance as at December 31	8,295,361				7,540,662				8,295,361	7,540,662	5,949,472
Atrium
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance as at January 1				241,284				240,873	241,284	240,873	212,122
Less: reinsurance reserves recoverable				38,768				40,531	38,768	40,531	30,009
Net balance as at January 1				202,516				200,342	202,516	200,342	182,113
Net incurred losses and LAE:
Current period									85,027	83,627	90,359
Prior periods									(7,751)	(13,817)	(20,940)
Total net incurred losses and LAE									77,276	69,810	69,419
Net paid losses:
Current period									(34,617)	(35,537)	(24,571)
Prior periods									(43,572)	(28,969)	(31,107)
Total net paid losses									(78,189)	(64,506)	(55,678)
Effect of exchange rate movement									1,253	(3,130)	4,488
Net balance as at December 31	202,856				202,516				202,856	202,516	200,342
Plus: reinsurance reserves recoverable	28,816				38,768				28,816	38,768	40,531
Balance as at December 31	231,672				241,284				231,672	241,284	240,873
StarStone
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance as at January 1				1,608,697				1,207,743	1,608,697	1,207,743	1,059,382
Less: reinsurance reserves recoverable				462,950				452,017	462,950	452,017	357,231
Net balance as at January 1				$ 1,145,747				$ 755,726	1,145,747	755,726	702,151
Net incurred losses and LAE:
Current period									598,468	578,892	341,628
Prior periods									129,168	94,491	(26,822)
Total net incurred losses and LAE									727,636	673,383	314,806
Net paid losses:
Current period									(96,261)	(150,778)	(54,867)
Prior periods									(435,372)	(326,352)	(252,926)
Total net paid losses									(531,633)	(477,130)	(307,793)
Effect of exchange rate movement									87	(9,481)	15,169
Acquired on purchase of subsidiaries									0	192,981	0
Assumed business									0	10,268	31,393
Ceded business									0	0	0
Net balance as at December 31	1,341,837				1,145,747				1,341,837	1,145,747	755,726
Plus: reinsurance reserves recoverable	537,291				462,950				537,291	462,950	452,017
Balance as at December 31	$ 1,879,128				$ 1,608,697				$ 1,879,128	$ 1,608,697	$ 1,207,743

Losses and Loss Adjustment Ex_5

Losses and Loss Adjustment Expenses - Net Incurred Losses and Loss Adjustment Expense Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Prior Period
Net losses paid, prior period									$ 1,669,004	$ 1,194,985	$ 862,921
Prior periods									48,917	(235,757)	(244,302)
Current Period
Net losses paid, current period									200,264	189,560	82,273
Net incurred losses and LAE, current period									823,658	689,782	437,853
Total
Net losses paid									1,869,268	1,384,545	945,194
Net change in case and LAE reserves									(497,930)	(460,394)	(341,030)
Net change in IBNR reserves									(651,181)	(439,416)	(406,588)
Increase (reduction) in estimates of net ultimate losses									720,157	484,735	197,576
Increase (reduction) in provisions for bad debt											(1,377)
Increase (reduction) in provisions for unallocated LAE									(53,963)	(58,648)	(53,712)
Amortization of deferred charges									38,627	13,781	14,359
Amortization of fair value adjustments									50,573	7,493	6,449
Total changes in fair value - fair value option									117,181	6,664	30,256
Total net incurred losses and LAE	$ 121,416	$ 222,417	$ 216,338	$ 312,404	$ 187,698	$ 153,974	$ 92,819	$ 19,534	872,575	454,025	193,551
Non-life Run-off
Prior Period
Net losses paid, prior period									1,182,804	838,812	578,888
Net change in case and LAE reserves, prior period									(553,996)	(552,124)	(381,450)
Net change in IBNR reserves, prior period									(848,776)	(573,127)	(393,100)
Increase (reduction) in estimates of net ultimate losses, prior period									(219,968)	(286,439)	(195,662)
Increase (reduction) in provisions for bad debt, prior period									0	0	(1,536)
Increase (reduction) in provisions for unallocated LAE, prior period									(57,844)	(65,401)	(54,071)
Amortization of deferred charges, prior period									38,627	13,781	14,359
Amortization of fair value adjustments, prior period									50,070	12,877	10,114
Changes in fair value - fair value option, prior period									117,181	6,664	30,256
Prior periods									(71,934)	(318,518)	(196,540)
Current Period
Net losses paid, current period									64,820	5	2,835
Net change in case and LAE reserves, current period									23,105	4,704	397
Net change in IBNR reserves, current period									35,194	7,742	2,373
Increase (reduction) in estimates of net ultimate losses, current period									123,119	12,451	5,605
Increase (reduction) in provisions for bad debt, current period									0	0	0
Increase (reduction) in provisions for unallocated LAE, current period									440	0	261
Amortization of deferred charges, current period									0	0	0
Amortization of fair value adjustments, current period									0	0	0
Changes in fair value - fair value option, current period									0	0	0
Net incurred losses and LAE, current period									123,559	12,451	5,866
Total
Net losses paid									1,247,624	838,817	581,723
Net change in case and LAE reserves									(530,891)	(547,420)	(381,053)
Net change in IBNR reserves									(813,582)	(565,385)	(390,727)
Increase (reduction) in estimates of net ultimate losses									(96,849)	(273,988)	(190,057)
Increase (reduction) in provisions for bad debt									0	0	(1,536)
Increase (reduction) in provisions for unallocated LAE									(57,404)	(65,401)	(53,810)
Amortization of deferred charges									38,627	13,781	14,359
Amortization of fair value adjustments									50,070	12,877	10,114
Total changes in fair value - fair value option									117,181	6,664	30,256
Total net incurred losses and LAE									51,625	(306,067)	(190,674)
Atrium
Prior Period
Net losses paid, prior period									43,572	28,969	31,107
Net change in case and LAE reserves, prior period									(13,278)	(10,161)	(13,324)
Net change in IBNR reserves, prior period									(38,380)	(27,507)	(35,650)
Increase (reduction) in estimates of net ultimate losses, prior period									(8,086)	(8,699)	(17,867)
Increase (reduction) in provisions for bad debt, prior period									0	0	89
Increase (reduction) in provisions for unallocated LAE, prior period									0	0	(442)
Amortization of fair value adjustments, prior period									335	(5,118)	(2,720)
Prior periods									(7,751)	(13,817)	(20,940)
Current Period
Net losses paid, current period									34,617	35,537	24,571
Net change in case and LAE reserves, current period									16,812	16,492	21,662
Net change in IBNR reserves, current period									33,598	31,598	43,329
Increase (reduction) in estimates of net ultimate losses, current period									85,027	83,627	89,562
Increase (reduction) in provisions for bad debt, current period									0	0	70
Increase (reduction) in provisions for unallocated LAE, current period									0	0	727
Amortization of fair value adjustments, current period									0	0	0
Net incurred losses and LAE, current period									85,027	83,627	90,359
Total
Net losses paid									78,189	64,506	55,678
Net change in case and LAE reserves									3,534	6,331	8,338
Net change in IBNR reserves									(4,782)	4,091	7,679
Increase (reduction) in estimates of net ultimate losses									76,941	74,928	71,695
Increase (reduction) in provisions for bad debt									0	0	159
Increase (reduction) in provisions for unallocated LAE									0	0	285
Amortization of deferred charges									0	0	0
Amortization of fair value adjustments									335	(5,118)	(2,720)
Total changes in fair value - fair value option									0	0	0
Total net incurred losses and LAE									77,276	69,810	69,419
StarStone
Prior Period
Net losses paid, prior period									435,372	326,352	252,926
Net change in case and LAE reserves, prior period									(85,983)	(81,491)	(63,785)
Net change in IBNR reserves, prior period									(214,787)	(144,212)	(208,244)
Increase (reduction) in estimates of net ultimate losses, prior period									134,602	100,649	(19,103)
Increase (reduction) in provisions for unallocated LAE, prior period									(5,602)	(5,892)	(6,774)
Amortization of fair value adjustments, prior period									168	(266)	(945)
Prior periods									129,168	94,491	(26,822)
Current Period
Net losses paid, current period									96,261	150,778	54,867
Net change in case and LAE reserves, current period									111,950	157,378	95,470
Net change in IBNR reserves, current period									381,214	258,091	184,704
Increase (reduction) in estimates of net ultimate losses, current period									589,425	566,247	335,041
Increase (reduction) in provisions for unallocated LAE, current period									9,043	12,645	6,587
Amortization of fair value adjustments, current period									0	0	0
Net incurred losses and LAE, current period									598,468	578,892	341,628
Total
Net losses paid									531,633	477,130	307,793
Net change in case and LAE reserves									25,967	75,887	31,685
Net change in IBNR reserves									166,427	113,879	(23,540)
Increase (reduction) in estimates of net ultimate losses									724,027	666,896	315,938
Increase (reduction) in provisions for bad debt											0
Increase (reduction) in provisions for unallocated LAE									3,441	6,753	(187)
Amortization of deferred charges									0	0	0
Amortization of fair value adjustments									168	(266)	(945)
Total changes in fair value - fair value option									0	0	0
Total net incurred losses and LAE									727,636	673,383	314,806
Other
Total
Net losses paid									11,822	4,092
Net change in case and LAE reserves									3,460	4,808
Net change in IBNR reserves									756	7,999
Increase (reduction) in estimates of net ultimate losses									16,038	16,899
Increase (reduction) in provisions for unallocated LAE									0	0
Amortization of deferred charges									0	0
Amortization of fair value adjustments									0	0
Total changes in fair value - fair value option									0	0
Total net incurred losses and LAE									$ 16,038	$ 16,899	$ 0

Losses and Loss Adjustment Ex_6

Losses and Loss Adjustment Expenses - Additional Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2019USD ($)commutation	Dec. 31, 2018USD ($)commutationpolicy_buy_back	Dec. 31, 2017USD ($)
Effects of Reinsurance [Line Items]
Net liabilities relating to direct asbestos and environmental exposures	$ 2,078,300				$ 1,703,600				$ 2,078,300	$ 1,703,600
Asbestos and environmental liabilities	2,259,600				1,839,700				2,259,600	1,839,700
Increase (decrease) in asbestos and environmental reserves, gross									419,900	(152,400)
Increase (reduction) in estimated future expenses									374,700	(159,600)
Net incurred losses and loss adjustment expenses	121,416	$ 222,417	$ 216,338	$ 312,404	$ 187,698	$ 153,974	$ 92,819	$ 19,534	872,575	454,025	$ 193,551
Net losses paid, prior period									1,669,004	1,194,985	862,921
Net incurred losses and LAE, current period									823,658	689,782	437,853
Net incurred losses and LAE, prior period									$ 48,917	(235,757)	(244,302)
Atrium Segment
Effects of Reinsurance [Line Items]
Syndicate underwriting capacity percentage									25.00%
Net incurred losses and loss adjustment expenses									$ 77,276	69,810	69,419
Increase (reduction) in estimates of net ultimate losses, prior period									(8,086)	(8,699)	(17,867)
Downward incurred loss development									(38,380)	(27,507)	(35,650)
Net change in case and LAE reserves, prior period									(13,278)	(10,161)	(13,324)
Net losses paid, prior period									43,572	28,969	31,107
Net incurred losses and LAE, current period									85,027	83,627	90,359
Net incurred losses and LAE, prior period									(7,751)	(13,817)	(20,940)
Amortization of fair value adjustments, prior period									335	(5,118)	(2,720)
Reduction in provisions for bad debt, prior period									0	0	89
Increase (reduction) in provisions for unallocated LAE, prior period									0	0	(442)
Non-life Run-off
Effects of Reinsurance [Line Items]
Net incurred losses and loss adjustment expenses									51,625	(306,067)	(190,674)
Increase (reduction) in estimates of net ultimate losses, prior period									(219,968)	(286,439)	(195,662)
Downward incurred loss development									(848,776)	(573,127)	(393,100)
Net change in case and LAE reserves, prior period									(553,996)	(552,124)	(381,450)
Net losses paid, prior period									1,182,804	838,812	578,888
Net incurred losses and LAE, current period									123,559	12,451	5,866
Net incurred losses and LAE, prior period									(71,934)	(318,518)	(196,540)
Increase (reduction) in provisions for unallocated LAE									(57,800)	(65,400)
Amortization of deferred charges, prior period									38,627	13,781	14,359
Amortization of fair value adjustments, prior period									50,070	12,877	10,114
Changes in fair value, fair value option									117,181	6,664	30,256
Net reduction in case and IBNR reserves											(774,600)
Reduction in provisions for bad debt, prior period									0	0	(1,536)
Increase (reduction) in provisions for unallocated LAE, prior period									(57,844)	(65,401)	(54,071)
Non-life Run-off | Workers' compensation
Effects of Reinsurance [Line Items]
Increase (reduction) in estimates of net ultimate losses, prior period									(136,418)	(154,560)	(155,009)
Downward incurred loss development									(188,944)	(115,648)	(151,797)
Net change in case and LAE reserves, prior period									(156,435)	(178,138)	(190,924)
Net losses paid, prior period									208,961	139,226	187,712
Net reduction in case and IBNR reserves									(1,402,800)	$ (1,125,300)
Reduction of open inventory claims, percentage										78.00%
Non-life Run-off | Workers' compensation, two portfolios
Effects of Reinsurance [Line Items]
Increase (reduction) in estimates of net ultimate losses, prior period									39,300
Downward incurred loss development									14,300
Net change in case and LAE reserves, prior period									53,600
Non-life Run-off | Six Communications
Effects of Reinsurance [Line Items]
Increase (reduction) in estimates of net ultimate losses, prior period									$ (6,100)
Number of commutations | commutation									6
Non-life Run-off | Seven Communications
Effects of Reinsurance [Line Items]
Increase (reduction) in estimates of net ultimate losses, prior period										$ (11,200)
Number of commutations | commutation										7
Non-life Run-off | Professional indemnity/Directors & Officers
Effects of Reinsurance [Line Items]
Increase (reduction) in estimates of net ultimate losses, prior period									$ (38,557)	$ 19,681	(10,211)
Downward incurred loss development									(104,984)	(130,957)	(24,559)
Net change in case and LAE reserves, prior period									(36,986)	(11,159)	(19,054)
Net losses paid, prior period									103,413	161,797	33,402
Ceded reinsurance asset increase	$ 13,500								13,500
Non-life Run-off | Asbestos
Effects of Reinsurance [Line Items]
Increase (reduction) in estimates of net ultimate losses, prior period									6,811	(64,949)	27,029
Downward incurred loss development									(146,749)	(151,662)	(76,837)
Net change in case and LAE reserves, prior period									35,003	(21,535)	(1,865)
Net losses paid, prior period									118,557	$ 108,248	105,731
Volume of claims reported, percentage, less than										3.00%
Average cost per claims, percentage										5.00%
Additional reserves recorded											60,500
Favorable development in other portfolios											(33,500)
Non-life Run-off | Asbestos Exposure, Six Commutations
Effects of Reinsurance [Line Items]
Increase (reduction) in estimates of net ultimate losses, prior period									$ (9,800)
Number of commutations | commutation									6
Non-life Run-off | Asbestos Exposure, Eight Communications and Two Policy Buy-Backs
Effects of Reinsurance [Line Items]
Increase (reduction) in estimates of net ultimate losses, prior period										$ (9,500)
Number of commutations | commutation										8
Number of policy buy-backs | policy_buy_back										2
Non-life Run-off | Construction defect
Effects of Reinsurance [Line Items]
Increase (reduction) in estimates of net ultimate losses, prior period									$ (1,260)	$ (18,221)	(33,025)
Downward incurred loss development									(25,025)	(33,146)	(42,804)
Net change in case and LAE reserves, prior period									(8,313)	(7,257)	(24,023)
Net losses paid, prior period									$ 32,078	22,182	$ 33,802
Reduction of open inventory claims, percentage											73.00%
Segment Concentration Risk | Liability Claims and Claims Adjustment Expense | Atrium Segment
Effects of Reinsurance [Line Items]
Percent of total investments									2.00%
Short-duration Insurance Contracts, Accident Years 1995-2005 | Non-life Run-off | Workers' compensation
Effects of Reinsurance [Line Items]
Increase (reduction) in estimates of net ultimate losses, prior period										22,700
Downward incurred loss development										14,300
Net change in case and LAE reserves, prior period										37,000
Short-duration Insurance Contracts, Accident Years 2010-2014 | Non-life Run-off | Workers' compensation
Effects of Reinsurance [Line Items]
Increase (reduction) in estimates of net ultimate losses, prior period										$ 30,200

Losses and Loss Adjustment Ex_7

Losses and Loss Adjustment Expenses - Net Incurred Losses by Line of Business (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Net losses paid, prior period	$ 1,669,004	$ 1,194,985	$ 862,921
Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Net losses paid, prior period	1,182,804	838,812	578,888
Net change in case and LAE reserves, prior period	(553,996)	(552,124)	(381,450)
Net change in IBNR reserves, prior period	(848,776)	(573,127)	(393,100)
Increase (reduction) in estimates of net ultimate losses, prior period	(219,968)	(286,439)	(195,662)
Asbestos | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Net losses paid, prior period	118,557	108,248	105,731
Net change in case and LAE reserves, prior period	35,003	(21,535)	(1,865)
Net change in IBNR reserves, prior period	(146,749)	(151,662)	(76,837)
Increase (reduction) in estimates of net ultimate losses, prior period	6,811	(64,949)	27,029
Environmental | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Net losses paid, prior period	16,899	21,273	26,542
Net change in case and LAE reserves, prior period	13,796	479	(9,438)
Net change in IBNR reserves, prior period	(15,707)	(7,599)	(7,748)
Increase (reduction) in estimates of net ultimate losses, prior period	14,988	14,153	9,356
General casualty | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Net losses paid, prior period	175,044	141,624	94,526
Net change in case and LAE reserves, prior period	(89,968)	(115,240)	(54,292)
Net change in IBNR reserves, prior period	(91,818)	(60,828)	(49,025)
Increase (reduction) in estimates of net ultimate losses, prior period	(6,742)	(34,444)	(8,791)
Workers' compensation/personal accident | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Net losses paid, prior period	208,961	139,226	187,712
Net change in case and LAE reserves, prior period	(156,435)	(178,138)	(190,924)
Net change in IBNR reserves, prior period	(188,944)	(115,648)	(151,797)
Increase (reduction) in estimates of net ultimate losses, prior period	(136,418)	(154,560)	(155,009)
Marine, aviation and transit | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Net losses paid, prior period	82,058	67,831	18,272
Net change in case and LAE reserves, prior period	(77,958)	(44,200)	(9,322)
Net change in IBNR reserves, prior period	(24,508)	(21,188)	(11,517)
Increase (reduction) in estimates of net ultimate losses, prior period	(20,408)	2,443	(2,567)
Construction defect | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Net losses paid, prior period	32,078	22,182	33,802
Net change in case and LAE reserves, prior period	(8,313)	(7,257)	(24,023)
Net change in IBNR reserves, prior period	(25,025)	(33,146)	(42,804)
Increase (reduction) in estimates of net ultimate losses, prior period	(1,260)	(18,221)	(33,025)
Professional indemnity/Directors & Officers | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Net losses paid, prior period	103,413	161,797	33,402
Net change in case and LAE reserves, prior period	(36,986)	(11,159)	(19,054)
Net change in IBNR reserves, prior period	(104,984)	(130,957)	(24,559)
Increase (reduction) in estimates of net ultimate losses, prior period	(38,557)	19,681	(10,211)
Motor | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Net losses paid, prior period	276,563	104,182	24,391
Net change in case and LAE reserves, prior period	(134,127)	(109,962)	(15,990)
Net change in IBNR reserves, prior period	(179,887)	(34,215)	(8,513)
Increase (reduction) in estimates of net ultimate losses, prior period	(37,451)	(39,995)	(112)
Property | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Net losses paid, prior period	94,093	22,178	13,440
Net change in case and LAE reserves, prior period	(73,259)	(24,271)	(11,196)
Net change in IBNR reserves, prior period	(7,358)	(11,497)	(5,162)
Increase (reduction) in estimates of net ultimate losses, prior period	13,476	(13,590)	(2,918)
Other | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Net losses paid, prior period	75,138	50,271	41,070
Net change in case and LAE reserves, prior period	(25,749)	(40,841)	(45,346)
Net change in IBNR reserves, prior period	(63,796)	(6,387)	(15,138)
Increase (reduction) in estimates of net ultimate losses, prior period	$ (14,407)	$ 3,043	$ (19,414)

Losses and Loss Adjustment Ex_8

Losses and Loss Adjustment Expenses - Breakdown of Gross and Net Losses and LAE Reserves by Major Category (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Gross
OLR	$ 5,394,529	$ 5,168,900
IBNR	5,057,868	4,468,991
Fair value adjustments - acquired companies	(167,511)	(214,518)
Fair value adjustments - fair value option	(217,933)	(374,752)
Total gross liability for unpaid losses and LAE	10,429,238	9,409,504	$ 7,398,088	$ 5,987,867
Net
ULAE	362,285	360,883
Total	8,047,055	7,455,078	5,447,863	4,505,123
Non-life Run-off
Gross
OLR	4,407,082	4,271,769
IBNR	3,945,407	3,527,767
Total	8,352,489	7,799,536
Fair value adjustments - acquired companies	(170,689)	(217,527)
Fair value adjustments - fair value option	(217,933)	(374,752)
Deferred charge on retroactive reinsurance	0	0
ULAE	331,494	333,405
Total gross liability for unpaid losses and LAE	8,295,361	7,540,662	5,949,472	4,716,363
Net
OLR	3,434,789	3,369,997
IBNR	3,272,348	2,918,333
Total Net Reserves	6,707,137	6,288,330
Fair value adjustments	(157,036)	(203,183)
Fair value adjustments - fair value option	(129,848)	(244,013)
Deferred charge on retroactive reinsurance	(272,462)	(86,585)
ULAE	331,494	333,405
Total	6,479,285	6,087,954	4,491,795	3,620,859
Non-life Run-off | Asbestos
Gross
OLR	542,681	341,544
IBNR	1,373,678	1,275,476
Total	1,916,359	1,617,020
Net
OLR	490,117	321,356
IBNR	1,271,982	1,171,754
Total Net Reserves	1,762,099	1,493,110
Non-life Run-off | Environmental
Gross
OLR	187,165	96,665
IBNR	156,121	126,035
Total	343,286	222,700
Net
OLR	173,878	93,095
IBNR	142,351	117,384
Total Net Reserves	316,229	210,479
Non-life Run-off | General casualty
Gross
OLR	501,863	500,033
IBNR	489,129	379,484
Total	990,992	879,517
Net
OLR	399,396	416,097
IBNR	421,426	298,612
Total Net Reserves	820,822	714,709
Non-life Run-off | Workers' compensation/personal accident
Gross
OLR	1,270,530	1,454,178
IBNR	977,808	832,615
Total	2,248,338	2,286,793
Net
OLR	963,578	1,115,116
IBNR	751,074	537,782
Total Net Reserves	1,714,652	1,652,898
Non-life Run-off | Marine, aviation and transit
Gross
OLR	290,067	301,783
IBNR	121,577	72,888
Total	411,644	374,671
Net
OLR	244,611	227,994
IBNR	100,135	78,023
Total Net Reserves	344,746	306,017
Non-life Run-off | Construction defect
Gross
OLR	29,772	20,712
IBNR	98,312	99,288
Total	128,084	120,000
Net
OLR	29,245	19,310
IBNR	94,888	94,736
Total Net Reserves	124,133	114,046
Non-life Run-off | Professional indemnity/Directors & Officers
Gross
OLR	693,760	603,665
IBNR	265,490	216,839
Total	959,250	820,504
Net
OLR	485,478	426,020
IBNR	170,926	166,898
Total Net Reserves	656,404	592,918
Non-life Run-off | Motor
Gross
OLR	480,668	564,307
IBNR	233,806	321,992
Total	714,474	886,299
Net
OLR	317,829	414,847
IBNR	165,543	304,874
Total Net Reserves	483,372	719,721
Non-life Run-off | Property
Gross
OLR	140,620	168,267
IBNR	63,604	37,631
Total	204,224	205,898
Net
OLR	122,010	160,873
IBNR	56,450	36,817
Total Net Reserves	178,460	197,690
Non-life Run-off | Other
Gross
OLR	269,956	220,615
IBNR	165,882	165,519
Total	435,838	386,134
Net
OLR	208,647	175,289
IBNR	97,573	111,453
Total Net Reserves	306,220	286,742
Atrium
Gross
OLR	89,141	94,885
IBNR	136,543	140,521
Total	225,684	235,406
Fair value adjustments - acquired companies	3,700	3,476
ULAE	2,288	2,402
Total gross liability for unpaid losses and LAE	231,672	241,284	240,873	212,122
Net
OLR	80,130	75,995
IBNR	117,257	121,272
Total Net Reserves	197,387	197,267
Fair value adjustments	3,181	2,847
ULAE	2,288	2,402
Total	202,856	202,516	200,342	182,113
Atrium | Marine, aviation and transit
Gross
OLR	24,668	32,999
IBNR	34,156	36,011
Total	58,824	69,010
Net
OLR	21,012	21,460
IBNR	24,829	24,207
Total Net Reserves	45,841	45,667
Atrium | Binding Authorities
Gross
OLR	31,507	28,512
IBNR	54,039	59,302
Total	85,546	87,814
Net
OLR	29,590	26,601
IBNR	51,984	57,016
Total Net Reserves	81,574	83,617
Atrium | Reinsurance
Gross
OLR	18,385	18,547
IBNR	29,533	27,653
Total	47,918	46,200
Net
OLR	16,209	15,180
IBNR	23,338	24,823
Total Net Reserves	39,547	40,003
Atrium | Accident and Health
Gross
OLR	5,460	4,972
IBNR	7,880	6,348
Total	13,340	11,320
Net
OLR	4,735	4,225
IBNR	7,469	5,837
Total Net Reserves	12,204	10,062
Atrium | Non-Marine Direct and Facultative
Gross
OLR	9,121	9,855
IBNR	10,935	11,207
Total	20,056	21,062
Net
OLR	8,584	8,529
IBNR	9,637	9,389
Total Net Reserves	18,221	17,918
StarStone
Gross
OLR	888,794	796,194
IBNR	962,353	787,894
Total	1,851,147	1,584,088
Fair value adjustments - acquired companies	(522)	(467)
ULAE	28,503	25,076
Total gross liability for unpaid losses and LAE	1,879,128	1,608,697	1,207,743	1,059,382
Net
OLR	560,784	533,129
IBNR	750,950	586,110
Total Net Reserves	1,311,734	1,119,239
Fair value adjustments	1,600	1,432
ULAE	28,503	25,076
Total	1,341,837	1,145,747	$ 755,726	$ 702,151
StarStone | General casualty
Gross
OLR	191,317	177,432
IBNR	481,473	331,432
Total	672,790	508,864
Net
OLR	156,086	137,828
IBNR	422,186	282,026
Total Net Reserves	578,272	419,854
StarStone | Workers' compensation/personal accident
Gross
OLR	55,902	49,373
IBNR	122,047	110,082
Total	177,949	159,455
Net
OLR	36,673	33,759
IBNR	74,661	68,969
Total Net Reserves	111,334	102,728
StarStone | Property
Gross
OLR	367,258	317,102
IBNR	152,514	123,511
Total	519,772	440,613
Net
OLR	158,156	151,774
IBNR	92,655	65,522
Total Net Reserves	250,811	217,296
StarStone | Marine
Gross
OLR	195,068	185,084
IBNR	173,319	182,453
Total	368,387	367,537
Net
OLR	162,073	163,889
IBNR	138,586	133,426
Total Net Reserves	300,659	297,315
StarStone | Aerospace
Gross
OLR	79,249	67,203
IBNR	33,000	40,416
Total	112,249	107,619
Net
OLR	47,796	45,879
IBNR	22,862	36,167
Total Net Reserves	$ 70,658	$ 82,046

Losses and Loss Adjustment Ex_9

Losses and Loss Adjustment Expenses - Net Loss Reserves By Acquisition And Year (Details) - Non-life Run-off $ in Thousands	Dec. 31, 2019USD ($)
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	$ 6,656,097
Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,740,810
Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	308,613
General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	813,541
Workers' compensation/personal accident
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,710,528
Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	342,989
Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	124,132
Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	655,260
Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	480,599
Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	178,215
Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	301,410
2009 and Prior
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	354,415
2009 and Prior | Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	180,887
2009 and Prior | Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	44,461
2009 and Prior | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	60,400
2009 and Prior | Workers' compensation/personal accident
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	3,362
2009 and Prior | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	8,890
2009 and Prior | Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2009 and Prior | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	9,438
2009 and Prior | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	25,131
2009 and Prior | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	3,957
2009 and Prior | Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	17,889
2010
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	141,306
2010 | Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	36,371
2010 | Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	10,364
2010 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	13,409
2010 | Workers' compensation/personal accident
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	49,828
2010 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	2,638
2010 | Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	18
2010 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	5,021
2010 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	5,756
2010 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	4,058
2010 | Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	13,843
2011
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	182,914
2011 | Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2011 | Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2011 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	24,072
2011 | Workers' compensation/personal accident
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	145,975
2011 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	3,256
2011 | Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	55
2011 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	8,619
2011 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	217
2011 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	298
2011 | Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	422
2012
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	57,336
2012 | Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2012 | Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2012 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	12,082
2012 | Workers' compensation/personal accident
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	3,986
2012 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2012 | Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2012 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	28,274
2012 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	500
2012 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	6,199
2012 | Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	6,295
2013
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	85,005
2013 | Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	7,973
2013 | Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2013 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	14,695
2013 | Workers' compensation/personal accident
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	58,316
2013 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2013 | Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2013 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2013 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	660
2013 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2013 | Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	3,361
2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	99,834
2014 | Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2014 | Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2014 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	30,313
2014 | Workers' compensation/personal accident
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2014 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	13,762
2014 | Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2014 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	35,795
2014 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	250
2014 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	14,127
2014 | Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	5,587
2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	453,355
2015 | Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	673
2015 | Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2015 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	46,838
2015 | Workers' compensation/personal accident
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	331,383
2015 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,589
2015 | Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	46,906
2015 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2015 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	14,785
2015 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	3,581
2015 | Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	7,600
2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	885,176
2016 | Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	387,808
2016 | Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	101,649
2016 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	5,389
2016 | Workers' compensation/personal accident
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	266,932
2016 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2016 | Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	18,982
2016 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	77,685
2016 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	203
2016 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2016 | Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	26,528
2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,116,945
2017 | Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	729,749
2017 | Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	26,798
2017 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	59,432
2017 | Workers' compensation/personal accident
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	73,069
2017 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	81,037
2017 | Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	22,973
2017 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2017 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	4,453
2017 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	455
2017 | Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	118,979
2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,724,191
2018 | Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	60,424
2018 | Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	17,247
2018 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	305,370
2018 | Workers' compensation/personal accident
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	385,223
2018 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	139,908
2018 | Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2018 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	326,157
2018 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	406,545
2018 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	66,755
2018 | Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	16,562
2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,555,620
2019 | Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	336,925
2019 | Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	108,094
2019 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	241,541
2019 | Workers' compensation/personal accident
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	392,454
2019 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	91,909
2019 | Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	35,198
2019 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	164,271
2019 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	22,099
2019 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	78,785
2019 | Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	$ 84,344

Losses and Loss Adjustment E_10

Losses and Loss Adjustment Expenses - Reconciliation Of Net Incurred Losses Prior To Provision For Bad Debt (Details) - Non-life Run-off - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	$ 6,656,097
Provision for Bad Debt	51,040
Total Net Reserves	6,707,137	$ 6,288,330
Asbestos
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,740,810
Provision for Bad Debt	21,289
Total Net Reserves	1,762,099	1,493,110
Environmental
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	308,613
Provision for Bad Debt	7,616
Total Net Reserves	316,229	210,479
General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	813,541
Provision for Bad Debt	7,281
Total Net Reserves	820,822	714,709
Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,710,528
Provision for Bad Debt	4,124
Total Net Reserves	1,714,652	1,652,898
Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	342,989
Provision for Bad Debt	1,757
Total Net Reserves	344,746	306,017
Construction defect
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	124,132
Provision for Bad Debt	1
Total Net Reserves	124,133	114,046
Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	655,260
Provision for Bad Debt	1,144
Total Net Reserves	656,404	592,918
Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	480,599
Provision for Bad Debt	2,773
Total Net Reserves	483,372	719,721
Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	178,215
Provision for Bad Debt	245
Total Net Reserves	178,460	197,690
Other
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	301,410
Provision for Bad Debt	4,810
Total Net Reserves	$ 306,220	$ 286,742

Losses and Loss Adjustment E_11

Losses and Loss Adjustment Expenses - Loss Triangles (Details) $ in Thousands	Dec. 31, 2019USD ($)claim	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)
Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	$ 6,656,097
Non-life Run-off | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	813,541
Non-life Run-off | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	342,989
Non-life Run-off | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	655,260
Non-life Run-off | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	480,599
Non-life Run-off | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	178,215
Non-life Run-off | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,710,528
Atrium
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,216,124
IBNR losses and loss expenses, net of reinsurance	$ 117,257
Cumulative Number of Claims | claim	25,094
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,018,737
Liabilities for unpaid losses and allocated LAE, net of reinsurance	197,387
Atrium | 2009 and Prior
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	553,325	$ 556,252	$ 558,768	$ 560,524	$ 564,128	$ 569,959	$ 573,576	$ 593,467	$ 609,275	$ 546,446
IBNR losses and loss expenses, net of reinsurance	$ 2,839
Cumulative Number of Claims | claim	1,381
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 544,625	543,253	544,954	543,591	541,597	536,706	531,928	521,740	510,113	491,683
Atrium | Accident Year - 2010
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	43,723	43,739	44,289	45,540	46,024	47,558	51,698	57,835	64,985	26,782
IBNR losses and loss expenses, net of reinsurance	$ 518
Cumulative Number of Claims | claim	201
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 41,631	41,386	41,223	40,650	40,049	39,022	36,530	32,223	25,127	11,442
Atrium | Accident Year - 2011
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	66,534	66,904	67,358	68,083	69,385	71,104	72,898	84,661	86,326
IBNR losses and loss expenses, net of reinsurance	$ 991
Cumulative Number of Claims | claim	252
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 65,040	64,669	65,199	63,914	62,560	58,627	52,450	39,997	17,138
Atrium | Accident Year - 2012
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	50,352	50,541	51,012	51,930	53,723	55,903	57,279	70,259
IBNR losses and loss expenses, net of reinsurance	$ 601
Cumulative Number of Claims | claim	385
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 47,598	46,901	45,321	44,430	42,152	37,991	31,474	11,228
Atrium | Accident Year - 2013
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	50,638	52,049	51,706	54,472	57,798	63,710	58,326
IBNR losses and loss expenses, net of reinsurance	$ 1,441
Cumulative Number of Claims | claim	566
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 46,637	46,099	45,387	43,511	40,443	32,064	14,579
Atrium | Accident Year - 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	56,737	57,667	60,542	66,104	69,500	69,253
IBNR losses and loss expenses, net of reinsurance	$ 3,104
Cumulative Number of Claims | claim	932
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 51,263	48,542	46,879	41,595	34,368	17,596
Atrium | Accident Year - 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	58,785	60,210	63,530	71,498	69,646
IBNR losses and loss expenses, net of reinsurance	$ 6,018
Cumulative Number of Claims | claim	1,515
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 47,704	44,544	38,987	29,687	12,029
Atrium | Accident Year - 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	67,031	70,179	75,318	73,190
IBNR losses and loss expenses, net of reinsurance	$ 10,449
Cumulative Number of Claims | claim	2,803
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 47,962	44,273	34,606	13,729
Atrium | Accident Year - 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	91,109	94,984	90,247
IBNR losses and loss expenses, net of reinsurance	$ 20,400
Cumulative Number of Claims | claim	5,053
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 56,057	47,723	14,371
Atrium | Accident Year - 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	91,621	85,044
IBNR losses and loss expenses, net of reinsurance	$ 37,297
Cumulative Number of Claims | claim	6,644
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 34,166	13,130
Atrium | Accident Year - 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	86,269
IBNR losses and loss expenses, net of reinsurance	$ 33,598
Cumulative Number of Claims | claim	5,362
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 36,054
StarStone | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,233,062
IBNR losses and loss expenses, net of reinsurance	$ 422,186
Cumulative Number of Claims | claim	39,890
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 654,790
Liabilities for unpaid losses and allocated LAE, net of reinsurance	578,272
StarStone | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	902,111
IBNR losses and loss expenses, net of reinsurance	$ 138,586
Cumulative Number of Claims | claim	49,902
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 601,452
Liabilities for unpaid losses and allocated LAE, net of reinsurance	300,659
StarStone | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,087,901
IBNR losses and loss expenses, net of reinsurance	$ 92,656
Cumulative Number of Claims | claim	42,108
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 837,090
Liabilities for unpaid losses and allocated LAE, net of reinsurance	250,811
StarStone | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	534,747
IBNR losses and loss expenses, net of reinsurance	$ 22,861
Cumulative Number of Claims | claim	23,704
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 464,089
Liabilities for unpaid losses and allocated LAE, net of reinsurance	70,658
StarStone | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	241,512
IBNR losses and loss expenses, net of reinsurance	$ 74,661
Cumulative Number of Claims | claim	13,881
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 130,178
Liabilities for unpaid losses and allocated LAE, net of reinsurance	111,334
StarStone | 2009 and Prior | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	82,574	82,535	82,324	82,400	82,329	82,278
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	2,543
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 82,546	82,534	82,318	82,395	82,319	82,257
StarStone | 2009 and Prior | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	27,100	27,076	27,050	27,018	27,002	27,070
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	1,991
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 27,092	27,077	27,042	27,015	26,990	26,939
StarStone | 2009 and Prior | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	114,991	114,633	113,696	113,206	113,118	113,828
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	2,901
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 113,338	113,143	113,237	112,987	112,957	112,693
StarStone | 2009 and Prior | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0	0	0
StarStone | 2009 and Prior | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0	0	0
StarStone | Accident Year - 2010 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	18,612	18,556	18,538	17,856	17,769	16,623
IBNR losses and loss expenses, net of reinsurance	$ 119
Cumulative Number of Claims | claim	729
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 18,466	18,555	18,537	17,855	17,768	15,555
StarStone | Accident Year - 2010 | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	19,050	19,040	19,176	19,114	19,270	22,347
IBNR losses and loss expenses, net of reinsurance	$ 144
Cumulative Number of Claims | claim	1,029
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 18,539	18,437	18,372	18,403	18,324	16,300
StarStone | Accident Year - 2010 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	72,088	72,146	72,134	72,072	73,437	74,893
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	1,557
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 71,969	72,148	72,131	72,069	71,958	69,070
StarStone | Accident Year - 2010 | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	18,772	18,970	18,896	18,382	18,073	18,441
IBNR losses and loss expenses, net of reinsurance	$ 17
Cumulative Number of Claims | claim	579
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 18,548	18,494	18,209	17,145	16,539	15,396
StarStone | Accident Year - 2010 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0	0	0
StarStone | Accident Year - 2011 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	26,159	25,422	24,971	25,745	25,435	21,101
IBNR losses and loss expenses, net of reinsurance	$ 765
Cumulative Number of Claims | claim	2,035
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 25,389	24,925	24,294	23,731	21,088	15,745
StarStone | Accident Year - 2011 | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	33,538	27,715	27,371	27,330	27,753	29,527
IBNR losses and loss expenses, net of reinsurance	$ 514
Cumulative Number of Claims | claim	1,961
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 32,558	32,803	32,643	32,397	31,152	29,395
StarStone | Accident Year - 2011 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	89,708	89,359	89,441	89,752	89,708	91,161
IBNR losses and loss expenses, net of reinsurance	$ 4
Cumulative Number of Claims | claim	1,621
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 89,387	89,345	89,366	89,113	88,608	87,411
StarStone | Accident Year - 2011 | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	58,770	59,647	58,114	57,681	57,257	58,786
IBNR losses and loss expenses, net of reinsurance	$ 61
Cumulative Number of Claims | claim	2,197
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 57,555	57,028	56,435	55,858	55,179	53,821
StarStone | Accident Year - 2011 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0	0	0
StarStone | Accident Year - 2012 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	42,055	39,477	40,095	43,936	48,251	56,891
IBNR losses and loss expenses, net of reinsurance	$ 3,059
Cumulative Number of Claims | claim	3,128
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 36,076	36,162	33,943	32,694	29,503	18,412
StarStone | Accident Year - 2012 | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	59,597	50,618	49,813	51,074	51,418	47,957
IBNR losses and loss expenses, net of reinsurance	$ 405
Cumulative Number of Claims | claim	2,422
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 57,711	57,206	56,589	55,446	53,711	49,727
StarStone | Accident Year - 2012 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	58,985	58,721	61,637	60,683	61,707	65,824
IBNR losses and loss expenses, net of reinsurance	$ 12
Cumulative Number of Claims | claim	1,501
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 57,753	55,474	55,274	54,308	52,168	48,103
StarStone | Accident Year - 2012 | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	57,185	57,450	56,159	56,212	55,370	55,675
IBNR losses and loss expenses, net of reinsurance	$ 125
Cumulative Number of Claims | claim	2,421
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 55,585	54,812	53,622	52,142	49,332	45,897
StarStone | Accident Year - 2012 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0	0	0
StarStone | Accident Year - 2013 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	87,575	78,788	76,172	77,756	66,888	72,771
IBNR losses and loss expenses, net of reinsurance	$ 9,817
Cumulative Number of Claims | claim	4,998
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 69,703	60,389	54,688	50,137	30,448	23,054
StarStone | Accident Year - 2013 | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	46,309	57,224	53,913	52,938	55,154	62,904
IBNR losses and loss expenses, net of reinsurance	$ 243
Cumulative Number of Claims | claim	2,226
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 38,733	29,071	27,237	25,135	21,213	12,529
StarStone | Accident Year - 2013 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	60,582	62,177	63,959	64,804	65,152	78,145
IBNR losses and loss expenses, net of reinsurance	$ 13
Cumulative Number of Claims | claim	1,959
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 60,416	59,277	53,172	51,086	46,285	30,880
StarStone | Accident Year - 2013 | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	76,964	77,393	74,900	70,511	70,180	72,098
IBNR losses and loss expenses, net of reinsurance	$ 274
Cumulative Number of Claims | claim	2,568
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 73,511	72,770	68,775	63,439	59,850	50,842
StarStone | Accident Year - 2013 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0	0	0
StarStone | Accident Year - 2014 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	101,748	90,588	90,335	92,812	92,793	91,369
IBNR losses and loss expenses, net of reinsurance	$ 19,074
Cumulative Number of Claims | claim	5,734
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 68,827	64,672	50,767	37,607	21,911	5,769
StarStone | Accident Year - 2014 | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	50,026	50,576	54,958	48,450	53,452	50,079
IBNR losses and loss expenses, net of reinsurance	$ 833
Cumulative Number of Claims | claim	4,003
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 43,789	42,420	36,773	32,332	24,813	10,878
StarStone | Accident Year - 2014 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	40,818	41,563	43,603	43,169	43,848	58,975
IBNR losses and loss expenses, net of reinsurance	$ 1,082
Cumulative Number of Claims | claim	2,094
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 37,240	36,106	34,563	31,617	18,830	5,500
StarStone | Accident Year - 2014 | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	48,657	54,408	52,341	53,553	53,541	65,208
IBNR losses and loss expenses, net of reinsurance	$ 464
Cumulative Number of Claims | claim	2,861
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 43,779	43,801	40,678	38,426	31,147	17,297
StarStone | Accident Year - 2014 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	14,873	15,203	15,662	18,290	17,199	15,607
IBNR losses and loss expenses, net of reinsurance	$ 1,421
Cumulative Number of Claims | claim	1,062
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 12,617	12,243	11,431	9,279	6,079	1,491
StarStone | Accident Year - 2015 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	131,156	123,208	110,179	111,067	105,135
IBNR losses and loss expenses, net of reinsurance	$ 22,056
Cumulative Number of Claims | claim	4,744
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 92,327	68,194	49,014	27,292	8,088
StarStone | Accident Year - 2015 | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	82,698	81,088	79,494	70,033	71,004
IBNR losses and loss expenses, net of reinsurance	$ 1,082
Cumulative Number of Claims | claim	5,742
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 59,478	56,154	50,062	30,562	10,871
StarStone | Accident Year - 2015 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	71,189	70,244	70,359	76,550	78,993
IBNR losses and loss expenses, net of reinsurance	$ 3,964
Cumulative Number of Claims | claim	5,720
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 64,764	63,880	55,372	28,652	10,433
StarStone | Accident Year - 2015 | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	71,196	73,183	72,519	69,499	66,335
IBNR losses and loss expenses, net of reinsurance	$ 1,318
Cumulative Number of Claims | claim	2,975
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 66,293	64,000	60,820	52,185	32,388
StarStone | Accident Year - 2015 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	45,812	47,338	50,103	55,505	54,977
IBNR losses and loss expenses, net of reinsurance	$ 4,905
Cumulative Number of Claims | claim	2,522
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 37,385	35,311	30,439	20,194	6,361
StarStone | Accident Year - 2016 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	169,207	140,601	129,130	125,367
IBNR losses and loss expenses, net of reinsurance	$ 39,548
Cumulative Number of Claims | claim	4,467
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 97,715	74,921	42,935	4,642
StarStone | Accident Year - 2016 | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	86,774	87,169	83,070	82,486
IBNR losses and loss expenses, net of reinsurance	$ 4,214
Cumulative Number of Claims | claim	6,904
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 72,475	57,265	41,696	12,131
StarStone | Accident Year - 2016 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	95,038	95,151	95,557	87,562
IBNR losses and loss expenses, net of reinsurance	$ 2,672
Cumulative Number of Claims | claim	6,791
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 85,023	75,387	58,035	26,838
StarStone | Accident Year - 2016 | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	45,380	48,180	45,019	37,741
IBNR losses and loss expenses, net of reinsurance	$ 1,714
Cumulative Number of Claims | claim	2,880
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 39,361	37,037	31,858	11,815
StarStone | Accident Year - 2016 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	55,150	54,793	54,121	62,942
IBNR losses and loss expenses, net of reinsurance	$ 9,101
Cumulative Number of Claims | claim	2,507
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 39,333	32,739	23,428	7,953
StarStone | Accident Year - 2017 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	194,259	162,599	137,614
IBNR losses and loss expenses, net of reinsurance	$ 64,639
Cumulative Number of Claims | claim	4,830
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 107,625	50,705	9,997
StarStone | Accident Year - 2017 | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	166,042	158,785	130,700
IBNR losses and loss expenses, net of reinsurance	$ 10,802
Cumulative Number of Claims | claim	8,524
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 108,000	68,952	25,258
StarStone | Accident Year - 2017 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	183,584	171,665	155,484
IBNR losses and loss expenses, net of reinsurance	$ 6,554
Cumulative Number of Claims | claim	8,034
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 139,555	98,267	37,410
StarStone | Accident Year - 2017 | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	56,354	35,075	31,380
IBNR losses and loss expenses, net of reinsurance	$ 3,142
Cumulative Number of Claims | claim	3,100
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 45,946	28,221	10,398
StarStone | Accident Year - 2017 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	29,676	39,089	43,366
IBNR losses and loss expenses, net of reinsurance	$ 6,037
Cumulative Number of Claims | claim	2,110
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 18,899	13,509	5,477
StarStone | Accident Year - 2018 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	181,499	159,324
IBNR losses and loss expenses, net of reinsurance	$ 90,672
Cumulative Number of Claims | claim	3,902
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 47,973	20,649
StarStone | Accident Year - 2018 | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	167,565	167,902
IBNR losses and loss expenses, net of reinsurance	$ 33,836
Cumulative Number of Claims | claim	9,881
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 104,825	41,427
StarStone | Accident Year - 2018 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	178,800	165,311
IBNR losses and loss expenses, net of reinsurance	$ 8,433
Cumulative Number of Claims | claim	6,653
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 98,065	59,187
StarStone | Accident Year - 2018 | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	55,986	59,498
IBNR losses and loss expenses, net of reinsurance	$ 3,980
Cumulative Number of Claims | claim	2,891
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 40,304	25,552
StarStone | Accident Year - 2018 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	39,247	44,615
IBNR losses and loss expenses, net of reinsurance	$ 13,672
Cumulative Number of Claims | claim	2,820
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 15,064	4,508
StarStone | Accident Year - 2019 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	198,218
IBNR losses and loss expenses, net of reinsurance	$ 172,437
Cumulative Number of Claims | claim	2,780
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 8,143
StarStone | Accident Year - 2019 | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	163,412
IBNR losses and loss expenses, net of reinsurance	$ 86,513
Cumulative Number of Claims | claim	5,219
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 38,252
StarStone | Accident Year - 2019 | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	122,118
IBNR losses and loss expenses, net of reinsurance	$ 69,922
Cumulative Number of Claims | claim	3,277
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 19,580
StarStone | Accident Year - 2019 | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	45,483
IBNR losses and loss expenses, net of reinsurance	$ 11,766
Cumulative Number of Claims | claim	1,232
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 23,207
StarStone | Accident Year - 2019 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	56,754
IBNR losses and loss expenses, net of reinsurance	$ 39,525
Cumulative Number of Claims | claim	2,860
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 6,880
2010 | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	1,092,197
Incurred losses and allocated loss adjustment expenses, net of reinsurance	788,475
IBNR losses and loss expenses, net of reinsurance	$ 42,290
Cumulative Number of Claims | claim	163,994
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 647,169
Liabilities for unpaid losses and allocated LAE, net of reinsurance	141,306
2010 | Non-life Run-off | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	13,409
2010 | Non-life Run-off | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	2,638
2010 | Non-life Run-off | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	5,021
2010 | Non-life Run-off | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	5,756
2010 | Non-life Run-off | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	4,058
2010 | Non-life Run-off | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	49,828
2010 | Non-life Run-off | 2009 and Prior
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	1,092,197
Incurred losses and allocated loss adjustment expenses, net of reinsurance	788,475	800,341	800,104	839,798	903,954	929,888	1,012,046	1,058,458	1,044,111	1,086,671
IBNR losses and loss expenses, net of reinsurance	$ 42,290
Cumulative Number of Claims | claim	163,994
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 647,169	630,627	612,530	584,306	567,605	553,769	511,054	428,312	261,446	$ 102,123
2011 | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	596,406
Incurred losses and allocated loss adjustment expenses, net of reinsurance	235,578
IBNR losses and loss expenses, net of reinsurance	$ 23,741
Cumulative Number of Claims | claim	112,875
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 52,664
Liabilities for unpaid losses and allocated LAE, net of reinsurance	182,914
2011 | Non-life Run-off | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	24,072
2011 | Non-life Run-off | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	3,256
2011 | Non-life Run-off | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	8,619
2011 | Non-life Run-off | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	217
2011 | Non-life Run-off | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	298
2011 | Non-life Run-off | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	145,975
2011 | Non-life Run-off | 2009 and Prior
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	596,121
Incurred losses and allocated loss adjustment expenses, net of reinsurance	235,348	256,864	270,905	315,912	370,995	424,001	490,822	586,636	621,742
IBNR losses and loss expenses, net of reinsurance	$ 23,721
Cumulative Number of Claims | claim	112,787
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 52,483	27,013	16,751	24,434	15,512	21,874	92,129	97,414	59,906
2011 | Non-life Run-off | Accident Year - 2010
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	285
Incurred losses and allocated loss adjustment expenses, net of reinsurance	142	142	142	140	140	140	141	449	412
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	26
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 142	142	142	140	140	140	140	115	91
2011 | Non-life Run-off | Accident Year - 2011
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	93	86	79	71	61	54	45	36	102
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	19
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 93	86	79	71	61	54	45	36	$ 27
2011 | Non-life Run-off | Accident Year - 2012
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	17	18	17	10	10	10	10	121
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	7
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 17	17	17	10	10	10	10	6
2011 | Non-life Run-off | Accident Year - 2013
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	15	15	15	15	15	43	23
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	16
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 15	15	15	15	15	10	6
2011 | Non-life Run-off | Accident Year - 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	15	18	3	3	3	1
IBNR losses and loss expenses, net of reinsurance	$ 3
Cumulative Number of Claims | claim	14
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 7	4	3	3	3	1
2011 | Non-life Run-off | Accident Year - 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	24	32	(2)	(2)	0
IBNR losses and loss expenses, net of reinsurance	$ 5
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 11	3	(2)	(2)	0
2011 | Non-life Run-off | Accident Year - 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	(99)	(110)	(139)	2
IBNR losses and loss expenses, net of reinsurance	$ 8
Cumulative Number of Claims | claim	2
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ (114)	(124)	(153)	2
2011 | Non-life Run-off | Accident Year - 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	15	21	0
IBNR losses and loss expenses, net of reinsurance	$ 2
Cumulative Number of Claims | claim	2
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 6	3	0
2011 | Non-life Run-off | Accident Year - 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	8	7
IBNR losses and loss expenses, net of reinsurance	$ 2
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4	1
2011 | Non-life Run-off | Accident Year - 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2012 | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	318,091
Incurred losses and allocated loss adjustment expenses, net of reinsurance	258,398
IBNR losses and loss expenses, net of reinsurance	$ 18,454
Cumulative Number of Claims | claim	47,753
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 201,062
Liabilities for unpaid losses and allocated LAE, net of reinsurance	57,336
2012 | Non-life Run-off | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	12,082
2012 | Non-life Run-off | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2012 | Non-life Run-off | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	28,274
2012 | Non-life Run-off | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	500
2012 | Non-life Run-off | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	6,199
2012 | Non-life Run-off | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	3,986
2012 | Non-life Run-off | 2009 and Prior
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	315,850
Incurred losses and allocated loss adjustment expenses, net of reinsurance	252,794	257,947	266,124	273,273	283,244	297,612	306,078	314,772
IBNR losses and loss expenses, net of reinsurance	$ 18,173
Cumulative Number of Claims | claim	47,708
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 197,236	187,091	173,921	163,845	139,542	108,965	67,858	2,754
2012 | Non-life Run-off | Accident Year - 2010
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	831
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,208	1,242	1,368	2,468	2,400	2,788	3,068	920
IBNR losses and loss expenses, net of reinsurance	$ 64
Cumulative Number of Claims | claim	6
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 801	776	748	712	685	618	463	167
2012 | Non-life Run-off | Accident Year - 2011
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	1,360
Incurred losses and allocated loss adjustment expenses, net of reinsurance	944	944	960	981	1,002	1,081	1,222	1,341
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	5
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 944	944	905	849	792	679	454	110
2012 | Non-life Run-off | Accident Year - 2012
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	50
Incurred losses and allocated loss adjustment expenses, net of reinsurance	152	152	363	371	315	332	45	74
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	6
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 152	152	152	152	47	45	45	$ 28
2012 | Non-life Run-off | Accident Year - 2013
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	124	124	385	396	390	109	866
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	5
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 124	124	124	124	124	109	100
2012 | Non-life Run-off | Accident Year - 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,048	1,093	1,189	1,420	2,843	2,736
IBNR losses and loss expenses, net of reinsurance	$ 23
Cumulative Number of Claims | claim	7
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 905	791	617	420	205	62
2012 | Non-life Run-off | Accident Year - 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	676	676	676	1,388	667
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	5
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 676	676	676	107	103
2012 | Non-life Run-off | Accident Year - 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	969	1,019	1,158	61
IBNR losses and loss expenses, net of reinsurance	$ 139
Cumulative Number of Claims | claim	2
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 89	89	51	2
2012 | Non-life Run-off | Accident Year - 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	91	153	69
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	4
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 91	39	12
2012 | Non-life Run-off | Accident Year - 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	141	0
IBNR losses and loss expenses, net of reinsurance	$ 18
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 27	0
2012 | Non-life Run-off | Accident Year - 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	251
IBNR losses and loss expenses, net of reinsurance	$ 37
Cumulative Number of Claims | claim	4
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 17
2013 | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	559,357
Incurred losses and allocated loss adjustment expenses, net of reinsurance	601,559
IBNR losses and loss expenses, net of reinsurance	$ 26,233
Cumulative Number of Claims | claim	83,843
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 516,554
Liabilities for unpaid losses and allocated LAE, net of reinsurance	85,005
2013 | Non-life Run-off | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	14,695
2013 | Non-life Run-off | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2013 | Non-life Run-off | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2013 | Non-life Run-off | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	660
2013 | Non-life Run-off | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2013 | Non-life Run-off | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	58,316
2013 | Non-life Run-off | 2009 and Prior
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	207,452
Incurred losses and allocated loss adjustment expenses, net of reinsurance	188,416	200,034	212,039	218,082	225,478	233,644	227,635
IBNR losses and loss expenses, net of reinsurance	$ 15,864
Cumulative Number of Claims | claim	44,881
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 140,814	136,898	129,803	128,474	109,918	84,422	48,802
2013 | Non-life Run-off | Accident Year - 2010
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	110,795
Incurred losses and allocated loss adjustment expenses, net of reinsurance	122,441	123,802	125,148	135,364	133,289	117,915	118,652
IBNR losses and loss expenses, net of reinsurance	$ 4,635
Cumulative Number of Claims | claim	11,537
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 105,873	105,023	98,341	92,782	75,351	48,783	24,752
2013 | Non-life Run-off | Accident Year - 2011
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	96,929
Incurred losses and allocated loss adjustment expenses, net of reinsurance	85,920	86,403	87,913	95,848	100,243	100,482	102,288
IBNR losses and loss expenses, net of reinsurance	$ 2,218
Cumulative Number of Claims | claim	11,175
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 79,113	77,290	75,055	70,498	63,952	52,455	30,323
2013 | Non-life Run-off | Accident Year - 2012
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	131,119
Incurred losses and allocated loss adjustment expenses, net of reinsurance	108,025	107,853	110,045	114,772	118,085	121,364	127,323
IBNR losses and loss expenses, net of reinsurance	$ 2,090
Cumulative Number of Claims | claim	10,420
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 99,781	96,780	92,445	86,916	74,663	59,095	33,361
2013 | Non-life Run-off | Accident Year - 2013
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	13,062
Incurred losses and allocated loss adjustment expenses, net of reinsurance	80,091	80,036	81,732	85,791	88,920	91,634	90,739
IBNR losses and loss expenses, net of reinsurance	$ 1,277
Cumulative Number of Claims | claim	5,649
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 74,556	71,487	68,866	62,876	52,638	37,653	$ 17,022
2013 | Non-life Run-off | Accident Year - 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	16,304	16,225	16,800	3,425	3,714	4,514
IBNR losses and loss expenses, net of reinsurance	$ 90
Cumulative Number of Claims | claim	175
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 16,123	15,959	15,804	2,256	1,747	993
2013 | Non-life Run-off | Accident Year - 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	250	329	982	280	265
IBNR losses and loss expenses, net of reinsurance	$ 54
Cumulative Number of Claims | claim	2
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 190	165	112	102	43
2013 | Non-life Run-off | Accident Year - 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	69	70	71	103
IBNR losses and loss expenses, net of reinsurance	$ 2
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 66	65	64	34
2013 | Non-life Run-off | Accident Year - 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	13	13	30
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 13	13	9
2013 | Non-life Run-off | Accident Year - 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	17	22
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 17	13
2013 | Non-life Run-off | Accident Year - 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	13
IBNR losses and loss expenses, net of reinsurance	$ 3
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 8
2014 | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	443,507
Incurred losses and allocated loss adjustment expenses, net of reinsurance	563,976
IBNR losses and loss expenses, net of reinsurance	$ 48,430
Cumulative Number of Claims | claim	29,169
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 464,142
Liabilities for unpaid losses and allocated LAE, net of reinsurance	99,834
2014 | Non-life Run-off | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	30,313
2014 | Non-life Run-off | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	13,762
2014 | Non-life Run-off | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	35,795
2014 | Non-life Run-off | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	250
2014 | Non-life Run-off | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	14,127
2014 | Non-life Run-off | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2014 | Non-life Run-off | 2009 and Prior
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	37,554
Incurred losses and allocated loss adjustment expenses, net of reinsurance	19,229	21,089	22,105	20,933	23,192	33,315
IBNR losses and loss expenses, net of reinsurance	$ 72
Cumulative Number of Claims | claim	6,363
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 16,934	16,884	16,337	15,652	13,090	7,044
2014 | Non-life Run-off | Accident Year - 2010
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	104,408
Incurred losses and allocated loss adjustment expenses, net of reinsurance	122,063	115,341	119,430	133,784	100,345	100,017
IBNR losses and loss expenses, net of reinsurance	$ 10,628
Cumulative Number of Claims | claim	6,454
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 103,753	102,128	102,138	87,233	69,414	29,424
2014 | Non-life Run-off | Accident Year - 2011
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	73,942
Incurred losses and allocated loss adjustment expenses, net of reinsurance	143,664	140,845	135,540	133,521	153,910	128,979
IBNR losses and loss expenses, net of reinsurance	$ 9,369
Cumulative Number of Claims | claim	6,693
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 126,650	120,564	113,406	110,338	109,574	84,042
2014 | Non-life Run-off | Accident Year - 2012
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	140,683
Incurred losses and allocated loss adjustment expenses, net of reinsurance	162,068	165,223	178,247	185,261	177,122	146,060
IBNR losses and loss expenses, net of reinsurance	$ 11,175
Cumulative Number of Claims | claim	5,086
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 132,508	127,958	128,692	119,807	89,618	47,495
2014 | Non-life Run-off | Accident Year - 2013
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	86,920
Incurred losses and allocated loss adjustment expenses, net of reinsurance	84,590	86,393	86,798	82,344	93,936	75,762
IBNR losses and loss expenses, net of reinsurance	$ 13,971
Cumulative Number of Claims | claim	3,171
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 62,009	63,256	55,882	47,537	40,237	21,752
2014 | Non-life Run-off | Accident Year - 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	5,589	5,765	7,420	13,817	9,503	12,826
IBNR losses and loss expenses, net of reinsurance	$ 1,731
Cumulative Number of Claims | claim	1,113
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 7,671	5,994	3,975	3,280	2,494	$ 1,462
2014 | Non-life Run-off | Accident Year - 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	17,799	18,616	20,709	15,529	33,545
IBNR losses and loss expenses, net of reinsurance	$ 73
Cumulative Number of Claims | claim	186
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 12,774	13,487	11,465	4,295	1,739
2014 | Non-life Run-off | Accident Year - 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	773	4,607	1,075	330
IBNR losses and loss expenses, net of reinsurance	$ 89
Cumulative Number of Claims | claim	44
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 601	571	556	20
2014 | Non-life Run-off | Accident Year - 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	8,196	3,920	5,074
IBNR losses and loss expenses, net of reinsurance	$ 423
Cumulative Number of Claims | claim	37
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,237	1,553	537
2014 | Non-life Run-off | Accident Year - 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	5	6
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	17
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 5	5
2014 | Non-life Run-off | Accident Year - 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0
IBNR losses and loss expenses, net of reinsurance	$ 899
Cumulative Number of Claims | claim	5
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance					69,067
2015 | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	1,700,879
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,263,072
IBNR losses and loss expenses, net of reinsurance	$ 145,858
Cumulative Number of Claims | claim	65,168
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 809,717
Liabilities for unpaid losses and allocated LAE, net of reinsurance	453,355
2015 | Non-life Run-off | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	46,838
2015 | Non-life Run-off | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,589
2015 | Non-life Run-off | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2015 | Non-life Run-off | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	14,785
2015 | Non-life Run-off | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	3,581
2015 | Non-life Run-off | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	1,382,732
Incurred losses and allocated loss adjustment expenses, net of reinsurance	813,976
IBNR losses and loss expenses, net of reinsurance	$ 67,228
Cumulative Number of Claims | claim	20,651
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 482,593
Liabilities for unpaid losses and allocated LAE, net of reinsurance	331,383
2015 | Non-life Run-off | 2009 and Prior
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	953,149
Incurred losses and allocated loss adjustment expenses, net of reinsurance	467,530	508,471	536,452	585,616	877,641
IBNR losses and loss expenses, net of reinsurance	$ 51,305
Cumulative Number of Claims | claim	11,285
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 165,931	140,691	114,682	67,899	23,605
2015 | Non-life Run-off | 2009 and Prior | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	921,259
Incurred losses and allocated loss adjustment expenses, net of reinsurance	418,931	462,612	488,356	538,290	834,148
IBNR losses and loss expenses, net of reinsurance	$ 43,677
Cumulative Number of Claims | claim	8,129
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 137,417	115,884	96,000	56,563	16,278
2015 | Non-life Run-off | Accident Year - 2010
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	49,049
Incurred losses and allocated loss adjustment expenses, net of reinsurance	49,031	51,348	55,761	52,889	53,914
IBNR losses and loss expenses, net of reinsurance	$ 6,860
Cumulative Number of Claims | claim	2,349
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 28,455	25,625	19,665	15,301	9,191
2015 | Non-life Run-off | Accident Year - 2010 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	31,919
Incurred losses and allocated loss adjustment expenses, net of reinsurance	26,913	27,922	30,407	31,402	34,360
IBNR losses and loss expenses, net of reinsurance	$ 1,877
Cumulative Number of Claims | claim	471
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 17,912	16,141	11,906	8,446	4,352
2015 | Non-life Run-off | Accident Year - 2011
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	124,400
Incurred losses and allocated loss adjustment expenses, net of reinsurance	127,673	127,098	129,386	130,994	137,102
IBNR losses and loss expenses, net of reinsurance	$ 18,940
Cumulative Number of Claims | claim	5,379
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 97,842	86,324	70,975	55,077	33,826
2015 | Non-life Run-off | Accident Year - 2011 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	76,789
Incurred losses and allocated loss adjustment expenses, net of reinsurance	67,236	66,781	68,013	69,009	73,723
IBNR losses and loss expenses, net of reinsurance	$ 5,836
Cumulative Number of Claims | claim	1,238
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 55,595	50,470	39,635	30,462	16,032
2015 | Non-life Run-off | Accident Year - 2012
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	178,936
Incurred losses and allocated loss adjustment expenses, net of reinsurance	192,338	192,896	200,749	197,716	187,288
IBNR losses and loss expenses, net of reinsurance	$ 23,706
Cumulative Number of Claims | claim	4,714
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 158,417	142,165	119,382	94,767	52,728
2015 | Non-life Run-off | Accident Year - 2012 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	120,298
Incurred losses and allocated loss adjustment expenses, net of reinsurance	98,532	100,187	106,625	108,251	110,007
IBNR losses and loss expenses, net of reinsurance	$ 5,774
Cumulative Number of Claims | claim	1,804
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 88,369	79,367	66,092	52,851	25,103
2015 | Non-life Run-off | Accident Year - 2013
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	229,182
Incurred losses and allocated loss adjustment expenses, net of reinsurance	184,189	188,572	199,593	196,205	189,430
IBNR losses and loss expenses, net of reinsurance	$ 16,027
Cumulative Number of Claims | claim	5,182
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 159,626	145,659	120,429	89,868	46,761
2015 | Non-life Run-off | Accident Year - 2013 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	146,237
Incurred losses and allocated loss adjustment expenses, net of reinsurance	112,199	113,056	121,010	122,238	124,726
IBNR losses and loss expenses, net of reinsurance	$ 6,789
Cumulative Number of Claims | claim	2,379
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 100,890	91,559	75,065	55,675	27,737
2015 | Non-life Run-off | Accident Year - 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	143,623
Incurred losses and allocated loss adjustment expenses, net of reinsurance	151,243	136,403	142,332	137,061	142,425
IBNR losses and loss expenses, net of reinsurance	$ 18,617
Cumulative Number of Claims | claim	10,707
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 125,226	109,149	90,738	64,353	30,747
2015 | Non-life Run-off | Accident Year - 2014 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	82,141
Incurred losses and allocated loss adjustment expenses, net of reinsurance	78,457	78,389	83,095	82,038	86,852
IBNR losses and loss expenses, net of reinsurance	$ 2,633
Cumulative Number of Claims | claim	3,680
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 72,696	65,561	53,308	38,051	17,824
2015 | Non-life Run-off | Accident Year - 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	22,540
Incurred losses and allocated loss adjustment expenses, net of reinsurance	68,388	63,776	65,243	68,034
IBNR losses and loss expenses, net of reinsurance	$ 5,125
Cumulative Number of Claims | claim	21,014
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 59,247	51,315	46,067	38,193	20,653
2015 | Non-life Run-off | Accident Year - 2015 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	4,089
Incurred losses and allocated loss adjustment expenses, net of reinsurance	11,125	12,295	13,488	12,623	18,647
IBNR losses and loss expenses, net of reinsurance	$ 545
Cumulative Number of Claims | claim	2,900
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 9,248	9,169	7,917	5,672	$ 3,034
2015 | Non-life Run-off | Accident Year - 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	13,837	12,750	12,504	14,172
IBNR losses and loss expenses, net of reinsurance	$ 2,053
Cumulative Number of Claims | claim	3,365
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 9,405	8,298	7,038	5,325
2015 | Non-life Run-off | Accident Year - 2016 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	536	583	955	873
IBNR losses and loss expenses, net of reinsurance	$ 72
Cumulative Number of Claims | claim	38
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 447	417	363	134
2015 | Non-life Run-off | Accident Year - 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	5,194	4,497	4,056
IBNR losses and loss expenses, net of reinsurance	$ 453
Cumulative Number of Claims | claim	900
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4,691	3,909	2,311
2015 | Non-life Run-off | Accident Year - 2017 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	41	61	358
IBNR losses and loss expenses, net of reinsurance	$ 21
Cumulative Number of Claims | claim	10
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 18	10	2
2015 | Non-life Run-off | Accident Year - 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,845	2,965
IBNR losses and loss expenses, net of reinsurance	$ 997
Cumulative Number of Claims | claim	270
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 835	558
2015 | Non-life Run-off | Accident Year - 2018 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	5	0
IBNR losses and loss expenses, net of reinsurance	$ 3
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1	0
2015 | Non-life Run-off | Accident Year - 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,804
IBNR losses and loss expenses, net of reinsurance	$ 1,775
Cumulative Number of Claims | claim	3
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 42
2015 | Non-life Run-off | Accident Year - 2019 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2016 | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	1,328,069
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,346,245
IBNR losses and loss expenses, net of reinsurance	$ 314,793
Cumulative Number of Claims | claim	25,325
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 461,069
Liabilities for unpaid losses and allocated LAE, net of reinsurance	885,176
2016 | Non-life Run-off | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	5,389
2016 | Non-life Run-off | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2016 | Non-life Run-off | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	77,685
2016 | Non-life Run-off | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	203
2016 | Non-life Run-off | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2016 | Non-life Run-off | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	465,906
Incurred losses and allocated loss adjustment expenses, net of reinsurance	410,152
IBNR losses and loss expenses, net of reinsurance	$ 32,956
Cumulative Number of Claims | claim	10,499
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 143,220
Liabilities for unpaid losses and allocated LAE, net of reinsurance	266,932
2016 | Non-life Run-off | 2009 and Prior
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	1,263,726
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,287,000	1,282,385	1,302,307	1,274,524
IBNR losses and loss expenses, net of reinsurance	$ 303,592
Cumulative Number of Claims | claim	22,892
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 428,904	317,309	213,509	96,937
2016 | Non-life Run-off | 2009 and Prior | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	413,381
Incurred losses and allocated loss adjustment expenses, net of reinsurance	362,905	369,093	377,285	412,474
IBNR losses and loss expenses, net of reinsurance	$ 26,747
Cumulative Number of Claims | claim	9,092
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 117,191	83,273	59,725	33,610
2016 | Non-life Run-off | Accident Year - 2010
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	32,571
Incurred losses and allocated loss adjustment expenses, net of reinsurance	25,710	28,093	32,866	32,451
IBNR losses and loss expenses, net of reinsurance	$ 5,047
Cumulative Number of Claims | claim	706
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 14,236	10,001	7,111	2,757
2016 | Non-life Run-off | Accident Year - 2010 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	24,075
Incurred losses and allocated loss adjustment expenses, net of reinsurance	19,541	22,383	26,034	25,330
IBNR losses and loss expenses, net of reinsurance	$ 3,660
Cumulative Number of Claims | claim	323
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 9,891	7,326	5,539	1,908
2016 | Non-life Run-off | Accident Year - 2011
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	17,291
Incurred losses and allocated loss adjustment expenses, net of reinsurance	18,829	19,754	19,920	17,291
IBNR losses and loss expenses, net of reinsurance	$ 2,830
Cumulative Number of Claims | claim	789
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 9,691	8,218	6,647	2,758
2016 | Non-life Run-off | Accident Year - 2011 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	15,376
Incurred losses and allocated loss adjustment expenses, net of reinsurance	16,327	16,501	16,399	15,376
IBNR losses and loss expenses, net of reinsurance	$ 1,456
Cumulative Number of Claims | claim	476
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 8,756	7,305	5,871	2,631
2016 | Non-life Run-off | Accident Year - 2012
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	13,717
Incurred losses and allocated loss adjustment expenses, net of reinsurance	12,717	14,765	17,020	13,717
IBNR losses and loss expenses, net of reinsurance	$ 2,012
Cumulative Number of Claims | claim	776
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 7,587	6,461	5,206	2,734
2016 | Non-life Run-off | Accident Year - 2012 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	13,074
Incurred losses and allocated loss adjustment expenses, net of reinsurance	11,379	13,276	15,465	13,074
IBNR losses and loss expenses, net of reinsurance	$ 1,093
Cumulative Number of Claims | claim	608
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 7,382	6,247	5,028	2,638
2016 | Non-life Run-off | Accident Year - 2013
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	373
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,120	1,237	1,312	373
IBNR losses and loss expenses, net of reinsurance	$ 827
Cumulative Number of Claims | claim	112
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 285	278	191	145
2016 | Non-life Run-off | Accident Year - 2013 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0
2016 | Non-life Run-off | Accident Year - 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	391
Incurred losses and allocated loss adjustment expenses, net of reinsurance	869	1,056	1,380	391
IBNR losses and loss expenses, net of reinsurance	$ 485
Cumulative Number of Claims | claim	50
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 366	284	207	178
2016 | Non-life Run-off | Accident Year - 2014 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0
2016 | Non-life Run-off | Accident Year - 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0
2016 | Non-life Run-off | Accident Year - 2015 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0
2016 | Non-life Run-off | Accident Year - 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	0
2016 | Non-life Run-off | Accident Year - 2016 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0	$ 0
2016 | Non-life Run-off | Accident Year - 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0
2016 | Non-life Run-off | Accident Year - 2017 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	0
2016 | Non-life Run-off | Accident Year - 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0
2016 | Non-life Run-off | Accident Year - 2018 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0
2016 | Non-life Run-off | Accident Year - 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2016 | Non-life Run-off | Accident Year - 2019 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2017 | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	1,638,437
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,439,218
IBNR losses and loss expenses, net of reinsurance	$ 804,563
Cumulative Number of Claims | claim	11,578
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 322,273
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,116,945
2017 | Non-life Run-off | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	59,432
2017 | Non-life Run-off | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	81,037
2017 | Non-life Run-off | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	0
2017 | Non-life Run-off | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	4,453
2017 | Non-life Run-off | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	455
2017 | Non-life Run-off | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	73,069
2017 | Non-life Run-off | 2009 and Prior
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	1,449,663
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,313,517	1,304,002	1,374,191
IBNR losses and loss expenses, net of reinsurance	$ 776,522
Cumulative Number of Claims | claim	11,481
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 243,621	165,471	80,189
2017 | Non-life Run-off | Accident Year - 2010
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	34,561
Incurred losses and allocated loss adjustment expenses, net of reinsurance	21,021	18,908	28,737
IBNR losses and loss expenses, net of reinsurance	$ 8,209
Cumulative Number of Claims | claim	36
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 9,121	7,394	4,287
2017 | Non-life Run-off | Accident Year - 2011
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	36,184
Incurred losses and allocated loss adjustment expenses, net of reinsurance	27,315	25,390	29,273
IBNR losses and loss expenses, net of reinsurance	$ 8,573
Cumulative Number of Claims | claim	7
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 12,971	9,257	4,125
2017 | Non-life Run-off | Accident Year - 2012
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	39,449
Incurred losses and allocated loss adjustment expenses, net of reinsurance	29,452	31,240	35,467
IBNR losses and loss expenses, net of reinsurance	$ 6,389
Cumulative Number of Claims | claim	11
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 18,603	15,371	10,348
2017 | Non-life Run-off | Accident Year - 2013
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	36,320
Incurred losses and allocated loss adjustment expenses, net of reinsurance	24,703	28,140	30,335
IBNR losses and loss expenses, net of reinsurance	$ 1,242
Cumulative Number of Claims | claim	11
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 21,277	15,711	9,508
2017 | Non-life Run-off | Accident Year - 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	31,474
Incurred losses and allocated loss adjustment expenses, net of reinsurance	15,996	16,984	20,315
IBNR losses and loss expenses, net of reinsurance	$ 2,195
Cumulative Number of Claims | claim	20
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 11,559	8,987	6,482
2017 | Non-life Run-off | Accident Year - 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	9,207
Incurred losses and allocated loss adjustment expenses, net of reinsurance	6,295	7,002	6,494
IBNR losses and loss expenses, net of reinsurance	$ 931
Cumulative Number of Claims | claim	8
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4,687	3,720	1,361
2017 | Non-life Run-off | Accident Year - 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	1,484
Incurred losses and allocated loss adjustment expenses, net of reinsurance	919	125	(4)
IBNR losses and loss expenses, net of reinsurance	$ 86
Cumulative Number of Claims | claim	3
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 434	66	(56)
2017 | Non-life Run-off | Accident Year - 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	95
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0	174
IBNR losses and loss expenses, net of reinsurance	$ 416
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0	$ 4
2017 | Non-life Run-off | Accident Year - 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0
2017 | Non-life Run-off | Accident Year - 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2018 | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	2,751,222
Incurred losses and allocated loss adjustment expenses, net of reinsurance	2,683,738
IBNR losses and loss expenses, net of reinsurance	$ 656,367
Cumulative Number of Claims | claim	323,179
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 959,547
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,724,191
2018 | Non-life Run-off | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	472,954
Incurred losses and allocated loss adjustment expenses, net of reinsurance	454,549
IBNR losses and loss expenses, net of reinsurance	$ 125,668
Cumulative Number of Claims | claim	58,661
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 149,179
Liabilities for unpaid losses and allocated LAE, net of reinsurance	305,370
2018 | Non-life Run-off | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	186,961
Incurred losses and allocated loss adjustment expenses, net of reinsurance	218,425
IBNR losses and loss expenses, net of reinsurance	$ 18,388
Cumulative Number of Claims | claim	86,679
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 78,517
Liabilities for unpaid losses and allocated LAE, net of reinsurance	139,908
2018 | Non-life Run-off | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	512,535
Incurred losses and allocated loss adjustment expenses, net of reinsurance	500,560
IBNR losses and loss expenses, net of reinsurance	$ 68,298
Cumulative Number of Claims | claim	74,349
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 174,403
Liabilities for unpaid losses and allocated LAE, net of reinsurance	326,157
2018 | Non-life Run-off | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	835,900
Incurred losses and allocated loss adjustment expenses, net of reinsurance	787,325
IBNR losses and loss expenses, net of reinsurance	$ 153,361
Cumulative Number of Claims | claim	15,493
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 380,780
Liabilities for unpaid losses and allocated LAE, net of reinsurance	406,545
2018 | Non-life Run-off | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	66,755
2018 | Non-life Run-off | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	493,222
Incurred losses and allocated loss adjustment expenses, net of reinsurance	485,995
IBNR losses and loss expenses, net of reinsurance	$ 201,526
Cumulative Number of Claims | claim	9,763
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 100,772
Liabilities for unpaid losses and allocated LAE, net of reinsurance	385,223
2018 | Non-life Run-off | 2009 and Prior
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	559,105
Incurred losses and allocated loss adjustment expenses, net of reinsurance	355,392	383,948
IBNR losses and loss expenses, net of reinsurance	$ 106,822
Cumulative Number of Claims | claim	209,846
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 36,359	41,953
2018 | Non-life Run-off | 2009 and Prior | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	97,189
Incurred losses and allocated loss adjustment expenses, net of reinsurance	42,901	48,898
IBNR losses and loss expenses, net of reinsurance	$ 3,969
Cumulative Number of Claims | claim	45,895
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 7,146	3,496
2018 | Non-life Run-off | 2009 and Prior | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	26,321
Incurred losses and allocated loss adjustment expenses, net of reinsurance	20,641	28,798
IBNR losses and loss expenses, net of reinsurance	$ (1,842)
Cumulative Number of Claims | claim	57,002
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ (3,789)	3,211
2018 | Non-life Run-off | 2009 and Prior | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	200,658
Incurred losses and allocated loss adjustment expenses, net of reinsurance	100,687	92,577
IBNR losses and loss expenses, net of reinsurance	$ (1,316)
Cumulative Number of Claims | claim	52,393
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 33,585	24,232
2018 | Non-life Run-off | 2009 and Prior | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	17,648
Incurred losses and allocated loss adjustment expenses, net of reinsurance	10,781	15,490
IBNR losses and loss expenses, net of reinsurance	$ (291)
Cumulative Number of Claims | claim	356
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 5,112	2,398
2018 | Non-life Run-off | 2009 and Prior | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	106,230
Incurred losses and allocated loss adjustment expenses, net of reinsurance	108,435	101,016
IBNR losses and loss expenses, net of reinsurance	$ 30,391
Cumulative Number of Claims | claim	1,742
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 10,643	3,633
2018 | Non-life Run-off | Accident Year - 2010
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	88,147
Incurred losses and allocated loss adjustment expenses, net of reinsurance	94,273	108,810
IBNR losses and loss expenses, net of reinsurance	$ 23,039
Cumulative Number of Claims | claim	13,799
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 23,761	11,109
2018 | Non-life Run-off | Accident Year - 2010 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	30,895
Incurred losses and allocated loss adjustment expenses, net of reinsurance	23,059	23,086
IBNR losses and loss expenses, net of reinsurance	$ 7,004
Cumulative Number of Claims | claim	1,885
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 7,835	5,345
2018 | Non-life Run-off | Accident Year - 2010 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	3,324
Incurred losses and allocated loss adjustment expenses, net of reinsurance	(6,710)	2,062
IBNR losses and loss expenses, net of reinsurance	$ (1,049)
Cumulative Number of Claims | claim	3,243
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ (7,715)	(3,689)
2018 | Non-life Run-off | Accident Year - 2010 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	25,474
Incurred losses and allocated loss adjustment expenses, net of reinsurance	33,765	39,710
IBNR losses and loss expenses, net of reinsurance	$ 8,220
Cumulative Number of Claims | claim	4,259
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 12,243	3,644
2018 | Non-life Run-off | Accident Year - 2010 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	23,548
Incurred losses and allocated loss adjustment expenses, net of reinsurance	15,187	13,937
IBNR losses and loss expenses, net of reinsurance	$ 1,015
Cumulative Number of Claims | claim	922
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 6,911	4,437
2018 | Non-life Run-off | Accident Year - 2010 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	24,838
Incurred losses and allocated loss adjustment expenses, net of reinsurance	24,102	25,149
IBNR losses and loss expenses, net of reinsurance	$ 8,642
Cumulative Number of Claims | claim	355
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4,542	317
2018 | Non-life Run-off | Accident Year - 2011
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	159,362
Incurred losses and allocated loss adjustment expenses, net of reinsurance	142,391	147,341
IBNR losses and loss expenses, net of reinsurance	$ 21,380
Cumulative Number of Claims | claim	14,100
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 47,261	26,998
2018 | Non-life Run-off | Accident Year - 2011 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	17,518
Incurred losses and allocated loss adjustment expenses, net of reinsurance	15,532	15,854
IBNR losses and loss expenses, net of reinsurance	$ 2,086
Cumulative Number of Claims | claim	1,404
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 6,621	2,236
2018 | Non-life Run-off | Accident Year - 2011 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	8,676
Incurred losses and allocated loss adjustment expenses, net of reinsurance	10,345	9,472
IBNR losses and loss expenses, net of reinsurance	$ 1,486
Cumulative Number of Claims | claim	3,966
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 5,901	4,953
2018 | Non-life Run-off | Accident Year - 2011 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	44,476
Incurred losses and allocated loss adjustment expenses, net of reinsurance	46,111	50,663
IBNR losses and loss expenses, net of reinsurance	$ 2,837
Cumulative Number of Claims | claim	3,745
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 19,732	12,453
2018 | Non-life Run-off | Accident Year - 2011 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	46,015
Incurred losses and allocated loss adjustment expenses, net of reinsurance	35,843	36,282
IBNR losses and loss expenses, net of reinsurance	$ 1,477
Cumulative Number of Claims | claim	1,209
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 12,112	5,631
2018 | Non-life Run-off | Accident Year - 2011 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	29,795
Incurred losses and allocated loss adjustment expenses, net of reinsurance	26,179	24,877
IBNR losses and loss expenses, net of reinsurance	$ 12,202
Cumulative Number of Claims | claim	401
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,825	(1,517)
2018 | Non-life Run-off | Accident Year - 2012
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	225,177
Incurred losses and allocated loss adjustment expenses, net of reinsurance	211,156	219,807
IBNR losses and loss expenses, net of reinsurance	$ 20,218
Cumulative Number of Claims | claim	14,055
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 74,768	31,845
2018 | Non-life Run-off | Accident Year - 2012 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	36,536
Incurred losses and allocated loss adjustment expenses, net of reinsurance	27,774	31,901
IBNR losses and loss expenses, net of reinsurance	$ 3,716
Cumulative Number of Claims | claim	1,567
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 11,097	1,104
2018 | Non-life Run-off | Accident Year - 2012 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	16,069
Incurred losses and allocated loss adjustment expenses, net of reinsurance	10,151	12,297
IBNR losses and loss expenses, net of reinsurance	$ (6,037)
Cumulative Number of Claims | claim	4,280
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 3,482	1,180
2018 | Non-life Run-off | Accident Year - 2012 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	55,366
Incurred losses and allocated loss adjustment expenses, net of reinsurance	65,180	68,004
IBNR losses and loss expenses, net of reinsurance	$ 12,943
Cumulative Number of Claims | claim	3,263
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 22,837	15,706
2018 | Non-life Run-off | Accident Year - 2012 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	62,432
Incurred losses and allocated loss adjustment expenses, net of reinsurance	60,620	55,338
IBNR losses and loss expenses, net of reinsurance	$ 6,949
Cumulative Number of Claims | claim	1,594
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 23,284	11,520
2018 | Non-life Run-off | Accident Year - 2012 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	28,788
Incurred losses and allocated loss adjustment expenses, net of reinsurance	27,723	29,174
IBNR losses and loss expenses, net of reinsurance	$ 12,633
Cumulative Number of Claims | claim	468
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 5,513	521
2018 | Non-life Run-off | Accident Year - 2013
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	263,008
Incurred losses and allocated loss adjustment expenses, net of reinsurance	255,973	267,132
IBNR losses and loss expenses, net of reinsurance	$ 54,609
Cumulative Number of Claims | claim	16,251
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 90,716	42,312
2018 | Non-life Run-off | Accident Year - 2013 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	42,528
Incurred losses and allocated loss adjustment expenses, net of reinsurance	44,782	54,061
IBNR losses and loss expenses, net of reinsurance	$ 5,123
Cumulative Number of Claims | claim	1,571
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 19,756	10,015
2018 | Non-life Run-off | Accident Year - 2013 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	43,798
Incurred losses and allocated loss adjustment expenses, net of reinsurance	29,464	35,462
IBNR losses and loss expenses, net of reinsurance	$ 2,404
Cumulative Number of Claims | claim	5,720
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 11,734	5,642
2018 | Non-life Run-off | Accident Year - 2013 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	56,251
Incurred losses and allocated loss adjustment expenses, net of reinsurance	74,018	60,010
IBNR losses and loss expenses, net of reinsurance	$ 9,407
Cumulative Number of Claims | claim	3,223
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 18,601	10,599
2018 | Non-life Run-off | Accident Year - 2013 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	74,615
Incurred losses and allocated loss adjustment expenses, net of reinsurance	61,396	68,022
IBNR losses and loss expenses, net of reinsurance	$ 14,105
Cumulative Number of Claims | claim	626
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 27,839	10,226
2018 | Non-life Run-off | Accident Year - 2013 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	37,716
Incurred losses and allocated loss adjustment expenses, net of reinsurance	37,866	38,309
IBNR losses and loss expenses, net of reinsurance	$ 16,786
Cumulative Number of Claims | claim	866
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 7,743	1,532
2018 | Non-life Run-off | Accident Year - 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	408,726
Incurred losses and allocated loss adjustment expenses, net of reinsurance	423,289	453,181
IBNR losses and loss expenses, net of reinsurance	$ 90,111
Cumulative Number of Claims | claim	18,887
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 181,166	93,536
2018 | Non-life Run-off | Accident Year - 2014 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	65,355
Incurred losses and allocated loss adjustment expenses, net of reinsurance	72,333	80,316
IBNR losses and loss expenses, net of reinsurance	$ 16,793
Cumulative Number of Claims | claim	2,210
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 28,071	13,427
2018 | Non-life Run-off | Accident Year - 2014 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	62,766
Incurred losses and allocated loss adjustment expenses, net of reinsurance	82,479	81,126
IBNR losses and loss expenses, net of reinsurance	$ 14,668
Cumulative Number of Claims | claim	5,862
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 40,926	22,990
2018 | Non-life Run-off | Accident Year - 2014 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	84,795
Incurred losses and allocated loss adjustment expenses, net of reinsurance	101,771	106,888
IBNR losses and loss expenses, net of reinsurance	$ 16,922
Cumulative Number of Claims | claim	3,563
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 40,189	21,640
2018 | Non-life Run-off | Accident Year - 2014 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	111,418
Incurred losses and allocated loss adjustment expenses, net of reinsurance	86,887	99,140
IBNR losses and loss expenses, net of reinsurance	$ 10,440
Cumulative Number of Claims | claim	1,140
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 46,359	20,746
2018 | Non-life Run-off | Accident Year - 2014 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	65,000
Incurred losses and allocated loss adjustment expenses, net of reinsurance	57,128	66,305
IBNR losses and loss expenses, net of reinsurance	$ 24,865
Cumulative Number of Claims | claim	1,335
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 14,666	3,248
2018 | Non-life Run-off | Accident Year - 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	354,692
Incurred losses and allocated loss adjustment expenses, net of reinsurance	467,650	474,678
IBNR losses and loss expenses, net of reinsurance	$ 97,189
Cumulative Number of Claims | claim	23,421
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 191,150	100,598
2018 | Non-life Run-off | Accident Year - 2015 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	77,011
Incurred losses and allocated loss adjustment expenses, net of reinsurance	102,399	91,825
IBNR losses and loss expenses, net of reinsurance	$ 28,926
Cumulative Number of Claims | claim	3,430
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 32,244	15,163
2018 | Non-life Run-off | Accident Year - 2015 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	26,007
Incurred losses and allocated loss adjustment expenses, net of reinsurance	72,055	65,209
IBNR losses and loss expenses, net of reinsurance	$ 8,758
Cumulative Number of Claims | claim	6,606
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 27,978	21,956
2018 | Non-life Run-off | Accident Year - 2015 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	45,515
Incurred losses and allocated loss adjustment expenses, net of reinsurance	79,028	97,288
IBNR losses and loss expenses, net of reinsurance	$ 19,285
Cumulative Number of Claims | claim	3,903
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 27,216	13,696
2018 | Non-life Run-off | Accident Year - 2015 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	129,271
Incurred losses and allocated loss adjustment expenses, net of reinsurance	126,345	127,187
IBNR losses and loss expenses, net of reinsurance	$ 15,912
Cumulative Number of Claims | claim	1,274
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 58,433	19,857
2018 | Non-life Run-off | Accident Year - 2015 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	38,734
Incurred losses and allocated loss adjustment expenses, net of reinsurance	34,649	39,336
IBNR losses and loss expenses, net of reinsurance	$ 16,909
Cumulative Number of Claims | claim	1,437
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4,066	1,355
2018 | Non-life Run-off | Accident Year - 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	170,311
Incurred losses and allocated loss adjustment expenses, net of reinsurance	174,845	172,245
IBNR losses and loss expenses, net of reinsurance	$ 55,384
Cumulative Number of Claims | claim	2,094
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 62,658	6,258
2018 | Non-life Run-off | Accident Year - 2016 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	28,825
Incurred losses and allocated loss adjustment expenses, net of reinsurance	36,585	28,825
IBNR losses and loss expenses, net of reinsurance	$ 14,377
Cumulative Number of Claims | claim	253
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 14,109	0
2018 | Non-life Run-off | Accident Year - 2016 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0
2018 | Non-life Run-off | Accident Year - 2016 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0
2018 | Non-life Run-off | Accident Year - 2016 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	90,166
Incurred losses and allocated loss adjustment expenses, net of reinsurance	93,824	92,100
IBNR losses and loss expenses, net of reinsurance	$ 19,439
Cumulative Number of Claims | claim	644
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 42,527	6,258
2018 | Non-life Run-off | Accident Year - 2016 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	44,686
Incurred losses and allocated loss adjustment expenses, net of reinsurance	38,945	44,686
IBNR losses and loss expenses, net of reinsurance	$ 21,267
Cumulative Number of Claims | claim	892
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 3,666	0
2018 | Non-life Run-off | Accident Year - 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	207,035
Incurred losses and allocated loss adjustment expenses, net of reinsurance	205,460	207,172
IBNR losses and loss expenses, net of reinsurance	$ 79,430
Cumulative Number of Claims | claim	4,163
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 72,794	52
2018 | Non-life Run-off | Accident Year - 2017 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	37,209
Incurred losses and allocated loss adjustment expenses, net of reinsurance	41,664	37,209
IBNR losses and loss expenses, net of reinsurance	$ 20,392
Cumulative Number of Claims | claim	230
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 11,048	0
2018 | Non-life Run-off | Accident Year - 2017 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0
2018 | Non-life Run-off | Accident Year - 2017 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0
2018 | Non-life Run-off | Accident Year - 2017 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	100,316
Incurred losses and allocated loss adjustment expenses, net of reinsurance	99,129	100,453
IBNR losses and loss expenses, net of reinsurance	$ 30,312
Cumulative Number of Claims | claim	2,797
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 48,655	52
2018 | Non-life Run-off | Accident Year - 2017 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	52,360
Incurred losses and allocated loss adjustment expenses, net of reinsurance	49,156	52,360
IBNR losses and loss expenses, net of reinsurance	$ 28,222
Cumulative Number of Claims | claim	998
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 5,900	0
2018 | Non-life Run-off | Accident Year - 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	315,659
Incurred losses and allocated loss adjustment expenses, net of reinsurance	285,038	315,659
IBNR losses and loss expenses, net of reinsurance	$ 88,411
Cumulative Number of Claims | claim	4,929
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 139,815	0
2018 | Non-life Run-off | Accident Year - 2018 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	39,888
Incurred losses and allocated loss adjustment expenses, net of reinsurance	40,753	39,888
IBNR losses and loss expenses, net of reinsurance	$ 20,480
Cumulative Number of Claims | claim	182
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 8,879	0
2018 | Non-life Run-off | Accident Year - 2018 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0
2018 | Non-life Run-off | Accident Year - 2018 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0	0
2018 | Non-life Run-off | Accident Year - 2018 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	180,471
Incurred losses and allocated loss adjustment expenses, net of reinsurance	157,556	180,471
IBNR losses and loss expenses, net of reinsurance	$ 42,546
Cumulative Number of Claims | claim	3,731
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 86,861	0
2018 | Non-life Run-off | Accident Year - 2018 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	65,075
Incurred losses and allocated loss adjustment expenses, net of reinsurance	60,923	65,075
IBNR losses and loss expenses, net of reinsurance	$ 24,137
Cumulative Number of Claims | claim	886
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 28,725	$ 0
2018 | Non-life Run-off | Accident Year - 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	68,271
IBNR losses and loss expenses, net of reinsurance	$ 19,774
Cumulative Number of Claims | claim	1,634
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 39,099
2018 | Non-life Run-off | Accident Year - 2019 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	6,767
IBNR losses and loss expenses, net of reinsurance	$ 2,802
Cumulative Number of Claims | claim	34
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 2,373
2018 | Non-life Run-off | Accident Year - 2019 | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2018 | Non-life Run-off | Accident Year - 2019 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2018 | Non-life Run-off | Accident Year - 2019 | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	39,757
IBNR losses and loss expenses, net of reinsurance	$ 11,457
Cumulative Number of Claims | claim	1,200
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 22,687
2018 | Non-life Run-off | Accident Year - 2019 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	20,889
IBNR losses and loss expenses, net of reinsurance	$ 5,472
Cumulative Number of Claims | claim	383
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 13,483
2019 | Non-life Run-off
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	1,705,335
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,761,512
IBNR losses and loss expenses, net of reinsurance	$ 1,047,146
Cumulative Number of Claims | claim	256,353
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 205,892
Liabilities for unpaid losses and allocated LAE, net of reinsurance	1,555,620
2019 | Non-life Run-off | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	281,908
Incurred losses and allocated loss adjustment expenses, net of reinsurance	266,888
IBNR losses and loss expenses, net of reinsurance	$ 185,818
Cumulative Number of Claims | claim	5,472
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 25,347
Liabilities for unpaid losses and allocated LAE, net of reinsurance	241,541
2019 | Non-life Run-off | Marine, aviation and transit
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	91,909
2019 | Non-life Run-off | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	187,895
Incurred losses and allocated loss adjustment expenses, net of reinsurance	208,203
IBNR losses and loss expenses, net of reinsurance	$ 73,407
Cumulative Number of Claims | claim	46,366
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 43,932
Liabilities for unpaid losses and allocated LAE, net of reinsurance	164,271
2019 | Non-life Run-off | Motor
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	22,099
2019 | Non-life Run-off | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	78,785
2019 | Non-life Run-off | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	409,360
Incurred losses and allocated loss adjustment expenses, net of reinsurance	407,878
IBNR losses and loss expenses, net of reinsurance	$ 379,724
Cumulative Number of Claims | claim	36,520
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 15,424
Liabilities for unpaid losses and allocated LAE, net of reinsurance	392,454
2019 | Non-life Run-off | 2009 and Prior
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	604,631
Incurred losses and allocated loss adjustment expenses, net of reinsurance	598,841
IBNR losses and loss expenses, net of reinsurance	$ 330,575
Cumulative Number of Claims | claim	81,869
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 21,678
2019 | Non-life Run-off | 2009 and Prior | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	4,396
Incurred losses and allocated loss adjustment expenses, net of reinsurance	4,415
IBNR losses and loss expenses, net of reinsurance	$ 670
Cumulative Number of Claims | claim	693
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,163
2019 | Non-life Run-off | 2009 and Prior | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	6,696
Incurred losses and allocated loss adjustment expenses, net of reinsurance	4,052
IBNR losses and loss expenses, net of reinsurance	$ 812
Cumulative Number of Claims | claim	10,399
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,323
2019 | Non-life Run-off | 2009 and Prior | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	5,143
Incurred losses and allocated loss adjustment expenses, net of reinsurance	3,609
IBNR losses and loss expenses, net of reinsurance	$ 1,270
Cumulative Number of Claims | claim	11,136
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 577
2019 | Non-life Run-off | Accident Year - 2010
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	35,515
Incurred losses and allocated loss adjustment expenses, net of reinsurance	24,353
IBNR losses and loss expenses, net of reinsurance	$ 3,586
Cumulative Number of Claims | claim	21,945
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4,923
2019 | Non-life Run-off | Accident Year - 2010 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	7,704
Incurred losses and allocated loss adjustment expenses, net of reinsurance	5,426
IBNR losses and loss expenses, net of reinsurance	$ 1,509
Cumulative Number of Claims | claim	1,213
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,031
2019 | Non-life Run-off | Accident Year - 2010 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	7,245
Incurred losses and allocated loss adjustment expenses, net of reinsurance	4,448
IBNR losses and loss expenses, net of reinsurance	$ 838
Cumulative Number of Claims | claim	5,300
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 326
2019 | Non-life Run-off | Accident Year - 2010 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	713
Incurred losses and allocated loss adjustment expenses, net of reinsurance	726
IBNR losses and loss expenses, net of reinsurance	$ 642
Cumulative Number of Claims | claim	1,352
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 38
2019 | Non-life Run-off | Accident Year - 2011
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	47,718
Incurred losses and allocated loss adjustment expenses, net of reinsurance	38,961
IBNR losses and loss expenses, net of reinsurance	$ 1,506
Cumulative Number of Claims | claim	21,380
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4,649
2019 | Non-life Run-off | Accident Year - 2011 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	11,381
Incurred losses and allocated loss adjustment expenses, net of reinsurance	8,817
IBNR losses and loss expenses, net of reinsurance	$ 2,347
Cumulative Number of Claims | claim	1,148
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 896
2019 | Non-life Run-off | Accident Year - 2011 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	18,093
Incurred losses and allocated loss adjustment expenses, net of reinsurance	10,292
IBNR losses and loss expenses, net of reinsurance	$ 1,947
Cumulative Number of Claims | claim	6,511
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 3,403
2019 | Non-life Run-off | Accident Year - 2011 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	2,470
Incurred losses and allocated loss adjustment expenses, net of reinsurance	2,410
IBNR losses and loss expenses, net of reinsurance	$ 2,334
Cumulative Number of Claims | claim	1,476
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 24
2019 | Non-life Run-off | Accident Year - 2012
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	70,661
Incurred losses and allocated loss adjustment expenses, net of reinsurance	51,937
IBNR losses and loss expenses, net of reinsurance	$ 27,520
Cumulative Number of Claims | claim	15,532
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 6,455
2019 | Non-life Run-off | Accident Year - 2012 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	16,910
Incurred losses and allocated loss adjustment expenses, net of reinsurance	13,592
IBNR losses and loss expenses, net of reinsurance	$ 5,262
Cumulative Number of Claims | claim	688
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 3,136
2019 | Non-life Run-off | Accident Year - 2012 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	30,127
Incurred losses and allocated loss adjustment expenses, net of reinsurance	18,012
IBNR losses and loss expenses, net of reinsurance	$ 4,348
Cumulative Number of Claims | claim	3,472
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 3,216
2019 | Non-life Run-off | Accident Year - 2012 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	6,274
Incurred losses and allocated loss adjustment expenses, net of reinsurance	6,173
IBNR losses and loss expenses, net of reinsurance	$ 6,090
Cumulative Number of Claims | claim	2,102
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 24
2019 | Non-life Run-off | Accident Year - 2013
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	110,426
Incurred losses and allocated loss adjustment expenses, net of reinsurance	87,708
IBNR losses and loss expenses, net of reinsurance	$ 36,879
Cumulative Number of Claims | claim	19,223
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 12,893
2019 | Non-life Run-off | Accident Year - 2013 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	22,355
Incurred losses and allocated loss adjustment expenses, net of reinsurance	16,934
IBNR losses and loss expenses, net of reinsurance	$ 7,515
Cumulative Number of Claims | claim	448
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 3,472
2019 | Non-life Run-off | Accident Year - 2013 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	46,758
Incurred losses and allocated loss adjustment expenses, net of reinsurance	35,881
IBNR losses and loss expenses, net of reinsurance	$ 9,945
Cumulative Number of Claims | claim	4,411
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 3,924
2019 | Non-life Run-off | Accident Year - 2013 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	16,686
Incurred losses and allocated loss adjustment expenses, net of reinsurance	16,223
IBNR losses and loss expenses, net of reinsurance	$ 14,578
Cumulative Number of Claims | claim	3,726
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 451
2019 | Non-life Run-off | Accident Year - 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	135,465
Incurred losses and allocated loss adjustment expenses, net of reinsurance	131,000
IBNR losses and loss expenses, net of reinsurance	$ 76,169
Cumulative Number of Claims | claim	21,224
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 26,910
2019 | Non-life Run-off | Accident Year - 2014 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	32,883
Incurred losses and allocated loss adjustment expenses, net of reinsurance	30,337
IBNR losses and loss expenses, net of reinsurance	$ 15,387
Cumulative Number of Claims | claim	456
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4,103
2019 | Non-life Run-off | Accident Year - 2014 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	46,557
Incurred losses and allocated loss adjustment expenses, net of reinsurance	46,982
IBNR losses and loss expenses, net of reinsurance	$ 17,975
Cumulative Number of Claims | claim	5,361
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 14,955
2019 | Non-life Run-off | Accident Year - 2014 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	34,945
Incurred losses and allocated loss adjustment expenses, net of reinsurance	35,252
IBNR losses and loss expenses, net of reinsurance	$ 30,998
Cumulative Number of Claims | claim	3,956
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 3,076
2019 | Non-life Run-off | Accident Year - 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	182,991
Incurred losses and allocated loss adjustment expenses, net of reinsurance	186,727
IBNR losses and loss expenses, net of reinsurance	$ 99,838
Cumulative Number of Claims | claim	35,276
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 34,610
2019 | Non-life Run-off | Accident Year - 2015 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	58,563
Incurred losses and allocated loss adjustment expenses, net of reinsurance	45,594
IBNR losses and loss expenses, net of reinsurance	$ 30,556
Cumulative Number of Claims | claim	346
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 4,552
2019 | Non-life Run-off | Accident Year - 2015 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	29,527
Incurred losses and allocated loss adjustment expenses, net of reinsurance	32,577
IBNR losses and loss expenses, net of reinsurance	$ 7,665
Cumulative Number of Claims | claim	5,856
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 7,193
2019 | Non-life Run-off | Accident Year - 2015 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	57,027
Incurred losses and allocated loss adjustment expenses, net of reinsurance	56,158
IBNR losses and loss expenses, net of reinsurance	$ 48,794
Cumulative Number of Claims | claim	6,158
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 3,635
2019 | Non-life Run-off | Accident Year - 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	238,798
Incurred losses and allocated loss adjustment expenses, net of reinsurance	308,254
IBNR losses and loss expenses, net of reinsurance	$ 179,237
Cumulative Number of Claims | claim	39,815
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 68,179
2019 | Non-life Run-off | Accident Year - 2016 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	50,518
Incurred losses and allocated loss adjustment expenses, net of reinsurance	62,866
IBNR losses and loss expenses, net of reinsurance	$ 44,899
Cumulative Number of Claims | claim	475
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 6,193
2019 | Non-life Run-off | Accident Year - 2016 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	2,892
Incurred losses and allocated loss adjustment expenses, net of reinsurance	52,708
IBNR losses and loss expenses, net of reinsurance	$ 28,916
Cumulative Number of Claims | claim	5,053
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 8,067
2019 | Non-life Run-off | Accident Year - 2016 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	84,171
Incurred losses and allocated loss adjustment expenses, net of reinsurance	85,396
IBNR losses and loss expenses, net of reinsurance	$ 73,087
Cumulative Number of Claims | claim	6,612
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 7,599
2019 | Non-life Run-off | Accident Year - 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	116,386
Incurred losses and allocated loss adjustment expenses, net of reinsurance	116,386
IBNR losses and loss expenses, net of reinsurance	$ 116,386
Cumulative Number of Claims | claim	2
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2019 | Non-life Run-off | Accident Year - 2017 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	32,188
Incurred losses and allocated loss adjustment expenses, net of reinsurance	32,188
IBNR losses and loss expenses, net of reinsurance	$ 32,188
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2019 | Non-life Run-off | Accident Year - 2017 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2019 | Non-life Run-off | Accident Year - 2017 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	84,197
Incurred losses and allocated loss adjustment expenses, net of reinsurance	84,197
IBNR losses and loss expenses, net of reinsurance	$ 84,197
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2019 | Non-life Run-off | Accident Year - 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	162,744
Incurred losses and allocated loss adjustment expenses, net of reinsurance	162,744
IBNR losses and loss expenses, net of reinsurance	$ 162,744
Cumulative Number of Claims | claim	2
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2019 | Non-life Run-off | Accident Year - 2018 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	45,010
Incurred losses and allocated loss adjustment expenses, net of reinsurance	45,010
IBNR losses and loss expenses, net of reinsurance	$ 45,010
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2019 | Non-life Run-off | Accident Year - 2018 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2019 | Non-life Run-off | Accident Year - 2018 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	117,734
Incurred losses and allocated loss adjustment expenses, net of reinsurance	117,734
IBNR losses and loss expenses, net of reinsurance	$ 117,734
Cumulative Number of Claims | claim	1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0
2019 | Non-life Run-off | Accident Year - 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	54,601
IBNR losses and loss expenses, net of reinsurance	$ 12,706
Cumulative Number of Claims | claim	85
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 25,595
2019 | Non-life Run-off | Accident Year - 2019 | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,709
IBNR losses and loss expenses, net of reinsurance	$ 475
Cumulative Number of Claims | claim	3
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 801
2019 | Non-life Run-off | Accident Year - 2019 | Professional indemnity/Directors & Officers
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	3,251
IBNR losses and loss expenses, net of reinsurance	$ 961
Cumulative Number of Claims | claim	3
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,525
2019 | Non-life Run-off | Accident Year - 2019 | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Total Net Reserves Acquired	0
Incurred losses and allocated loss adjustment expenses, net of reinsurance	0
IBNR losses and loss expenses, net of reinsurance	$ 0
Cumulative Number of Claims | claim	0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 0

Losses and Loss Adjustment E_12

Losses and Loss Adjustment Expenses - Average Annual Duration of Claims (Details)	Dec. 31, 2019
Atrium
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	24.69%
Year 2	32.30%
Year 3	14.57%
Year 4	8.25%
Year 5	4.69%
Year 6	2.47%
Year 7	1.88%
Year 8	0.63%
Year 9	0.47%
Year 10	0.56%
StarStone | Workers' compensation
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	13.40%
Year 2	28.61%
Year 3	19.73%
Year 4	12.35%
Year 5	4.99%
Year 6	2.51%
Year 7	0.00%
Year 8	0.00%
Year 9	0.00%
Year 10	0.00%
StarStone | General casualty
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	5.87%
Year 2	17.83%
Year 3	17.73%
Year 4	17.98%
Year 5	13.06%
Year 6	5.94%
Year 7	3.72%
Year 8	1.44%
Year 9	0.71%
Year 10	(0.23%)
StarStone | Marine
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	18.70%
Year 2	29.98%
Year 3	19.76%
Year 4	9.79%
Year 5	5.60%
Year 6	3.86%
Year 7	4.63%
Year 8	0.32%
Year 9	(0.09%)
Year 10	0.30%
StarStone | Property
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	20.98%
Year 2	29.19%
Year 3	27.01%
Year 4	8.82%
Year 5	2.69%
Year 6	3.22%
Year 7	0.54%
Year 8	1.04%
Year 9	0.00%
Year 10	0.20%
StarStone | Aerospace
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	37.03%
Year 2	31.40%
Year 3	16.33%
Year 4	4.98%
Year 5	4.76%
Year 6	3.00%
Year 7	1.81%
Year 8	2.68%
Year 9	1.21%
Year 10	0.29%
2010 | Non-life Run-off
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	12.95%
Year 2	20.21%
Year 3	21.16%
Year 4	10.49%
Year 5	5.42%
Year 6	1.75%
Year 7	2.12%
Year 8	3.58%
Year 9	2.30%
Year 10	2.10%
2011 | Non-life Run-off
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	25.48%
Year 2	15.94%
Year 3	(2.22%)
Year 4	(29.82%)
Year 5	(2.70%)
Year 6	3.79%
Year 7	(3.32%)
Year 8	4.38%
Year 9	10.83%
2012 | Non-life Run-off
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	1.18%
Year 2	25.49%
Year 3	16.08%
Year 4	12.00%
Year 5	9.56%
Year 6	4.26%
Year 7	5.22%
Year 8	4.02%
2013 | Non-life Run-off
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	25.64%
Year 2	21.47%
Year 3	15.78%
Year 4	10.91%
Year 5	6.08%
Year 6	3.86%
Year 7	2.14%
2014 | Non-life Run-off
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	33.91%
Year 2	23.93%
Year 3	10.99%
Year 4	7.95%
Year 5	3.44%
Year 6	2.08%
2015 | Non-life Run-off
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	17.22%
Year 2	16.89%
Year 3	12.71%
Year 4	9.69%
Year 5	7.60%
2015 | Non-life Run-off | Workers' compensation
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	13.56%
Year 2	16.89%
Year 3	12.58%
Year 4	9.62%
Year 5	6.64%
2016 | Non-life Run-off
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	7.84%
Year 2	9.46%
Year 3	8.15%
Year 4	8.80%
2016 | Non-life Run-off | Workers' compensation
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	9.94%
Year 2	8.63%
Year 3	6.82%
Year 4	9.53%
2017 | Non-life Run-off
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	8.08%
Year 2	7.62%
Year 3	6.69%
2018 | Non-life Run-off
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	13.22%
Year 2	22.54%
2018 | Non-life Run-off | Workers' compensation
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	1.87%
Year 2	18.87%
2018 | Non-life Run-off | Marine, aviation and transit
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	25.75%
Year 2	10.20%
2018 | Non-life Run-off | General casualty
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	11.17%
Year 2	21.65%
2018 | Non-life Run-off | Professional indemnity/Directors & Officers
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	20.37%
Year 2	14.47%
2018 | Non-life Run-off | Motor
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	10.30%
Year 2	38.06%
2019 | Non-life Run-off
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	11.69%
2019 | Non-life Run-off | Workers' compensation
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	3.78%
2019 | Non-life Run-off | General casualty
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	9.50%
2019 | Non-life Run-off | Professional indemnity/Directors & Officers
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	21.10%

Losses and Loss Adjustment E_13

Losses and Loss Adjustment Expenses - Reconciliation of Incurred and Paid Loss Development (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Atrium
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	$ 197,387
Reinsurance recoverable on unpaid losses	28,297
Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments	225,684	$ 235,406
StarStone
Liability for Claims and Claims Adjustment Expense [Line Items]
Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments	1,851,147	1,584,088
StarStone | General casualty
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	578,272
Reinsurance recoverable on unpaid losses	94,518
Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments	672,790	508,864
StarStone | Marine
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	300,659
Reinsurance recoverable on unpaid losses	67,728
Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments	368,387	367,537
StarStone | Property
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	250,811
Reinsurance recoverable on unpaid losses	268,961
Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments	519,772	440,613
StarStone | Aerospace
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	70,658
Reinsurance recoverable on unpaid losses	41,591
Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments	112,249	107,619
StarStone | Workers' compensation
Liability for Claims and Claims Adjustment Expense [Line Items]
Liabilities for unpaid losses and allocated LAE, net of reinsurance	111,334
Reinsurance recoverable on unpaid losses	66,615
Gross liability for unpaid losses and LAE before unallocated loss adjustment expenses and fair value adjustments	$ 177,949	$ 159,455

Defendant Asbestos and Enviro_3

Defendant Asbestos and Environmental Liabilities - Liability for Asbestos and Liability Claims (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Estimated future expenses	$ 51,637	$ 19,843
Fair value adjustments	(314,824)	(84,650)
Defendant asbestos and environmental liabilities	847,685	203,320	$ 219,164	$ 234,020
Insurance recoveries related to defendant asbestos and environmental liabilities	549,593	183,676
Fair value adjustments	(100,738)	(47,868)
Insurance balances recoverable	448,855	135,808
Net liabilities relating to defendant asbestos and environmental exposures	398,830	67,512	$ 96,838	$ 100,988
Defendant asbestos liabilities
Loss Contingencies [Line Items]
Defendant asbestos and environmental liabilities	1,100,593	265,975
Defendant environmental liabilities
Loss Contingencies [Line Items]
Defendant asbestos and environmental liabilities	$ 10,279	$ 2,152

Defendant Asbestos and Enviro_4

Defendant Asbestos and Environmental Liabilities - Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Liability for Asbestos and Environmental Claims, Net [Roll Forward]
Balance as at January 1	$ 203,320	$ 219,164	$ 234,020
Less: Insurance balances recoverable	135,808	122,326	133,032
Net balance as at January 1	67,512	96,838	100,988
Total net paid claims	(13,708)	(6,351)	(6,927)
Amounts recorded in other income (expense):
Net change in actuarial estimates	(4,263)	(23,221)	2,800
Amortization of fair value adjustments	13,500	246	(23)
Total other expense (income)	9,237	(22,975)	2,777
Acquired on purchase of subsidiaries	335,789	0	0
Net balance as at December 31	398,830	67,512	96,838
Plus: Insurance balances recoverable	448,855	135,808	122,326
Balance as at December 31	$ 847,685	$ 203,320	$ 219,164

Defendant Asbestos and Enviro_5

Defendant Asbestos and Environmental Liabilities - Additional Information (Details) $ in Millions	Dec. 31, 2019USD ($)site	Dec. 31, 2018USD ($)
Liability for Claims and Claims Adjustment Expense [Line Items]
Asbestos and environmental liabilities	$ 2,259.6	$ 1,839.7
Number of hazardous waste disposal sites | site	22
Defendant asbestos liabilities
Liability for Claims and Claims Adjustment Expense [Line Items]
Asbestos and environmental liabilities	$ 1,100.6	266
Defendant environmental liabilities
Liability for Claims and Claims Adjustment Expense [Line Items]
Asbestos and environmental liabilities	$ 10.3	$ 2.2

Fair Value Measurements - Categ

Fair Value Measurements - Categorized Investments and Assets Carried at Cost or Amortized Cost and Fair Value Among Levels (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	$ 729,721	$ 367,125
Total investments	9,612,888	8,697,892
Reinsurance balances recoverable on paid and unpaid losses	(88,086)	(130,739)
Other Assets:
Losses and LAE	2,621,122	2,874,055
U.S. government and agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	736,043	510,245
U.K. government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	161,772	300,631
Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	5,697,067	4,839,840
Municipal
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	167,882	130,265
Residential mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	471,836	773,557
Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	900,029	713,063
Asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	775,402	636,481
Private equity funds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	268,800
CLO equities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	87,600
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	729,721	367,125
Total investments	12,881,236	11,037,554
Cash and cash equivalents	396,083	264,985
Other Assets:
Losses and LAE	2,621,122	2,874,055
Recurring | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	9,612,888	8,697,892
Recurring | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	2,524,420	1,957,757
Recurring | Reinsurance balances recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	695,518	739,591
Recurring | Other Assets
Other Assets:
Derivative instruments	2,011	6,701
Recurring | Other Liabilities
Other Liabilities:
Derivative instruments	15,558	983
Recurring | Designated as Hedging Instrument | Other Assets
Other Assets:
Derivative instruments	642	1,615
Recurring | Designated as Hedging Instrument | Other Liabilities
Other Liabilities:
Derivative instruments	11,452	300
Recurring | Not Designated as Hedging Instrument | Other Assets
Other Assets:
Derivative instruments	1,369	5,086
Recurring | Not Designated as Hedging Instrument | Other Liabilities
Other Liabilities:
Derivative instruments	4,106	683
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	430,357	102,102
Total investments	430,357	102,102
Cash and cash equivalents	173,892	243,839
Other Assets:
Losses and LAE	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Reinsurance balances recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Assets
Other Assets:
Derivative instruments	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other Liabilities
Other Liabilities:
Derivative instruments	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Designated as Hedging Instrument | Other Assets
Other Assets:
Derivative instruments	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Designated as Hedging Instrument | Other Liabilities
Other Liabilities:
Derivative instruments	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Not Designated as Hedging Instrument | Other Assets
Other Assets:
Derivative instruments	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Not Designated as Hedging Instrument | Other Liabilities
Other Liabilities:
Derivative instruments	0	0
Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	30,565	36,313
Total investments	10,166,877	9,086,971
Cash and cash equivalents	222,191	21,146
Other Assets:
Losses and LAE	0	0
Recurring | Significant Other Observable Inputs (Level 2) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	9,612,888	8,643,996
Recurring | Significant Other Observable Inputs (Level 2) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	509,217	391,882
Recurring | Significant Other Observable Inputs (Level 2) | Reinsurance balances recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	0	0
Recurring | Significant Other Observable Inputs (Level 2) | Other Assets
Other Assets:
Derivative instruments	2,011	6,701
Recurring | Significant Other Observable Inputs (Level 2) | Other Liabilities
Other Liabilities:
Derivative instruments	15,558	983
Recurring | Significant Other Observable Inputs (Level 2) | Designated as Hedging Instrument | Other Assets
Other Assets:
Derivative instruments	642	1,615
Recurring | Significant Other Observable Inputs (Level 2) | Designated as Hedging Instrument | Other Liabilities
Other Liabilities:
Derivative instruments	11,452	300
Recurring | Significant Other Observable Inputs (Level 2) | Not Designated as Hedging Instrument | Other Assets
Other Assets:
Derivative instruments	1,369	5,086
Recurring | Significant Other Observable Inputs (Level 2) | Not Designated as Hedging Instrument | Other Liabilities
Other Liabilities:
Derivative instruments	4,106	683
Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	268,799	228,710
Total investments	356,668	321,973
Cash and cash equivalents	0	0
Other Assets:
Losses and LAE	2,621,122	2,874,055
Recurring | Significant Unobservable Inputs (Level 3) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	53,896
Recurring | Significant Unobservable Inputs (Level 3) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	87,869	39,367
Recurring | Significant Unobservable Inputs (Level 3) | Reinsurance balances recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Reinsurance balances recoverable on paid and unpaid losses	695,518	739,591
Recurring | Significant Unobservable Inputs (Level 3) | Other Assets
Other Assets:
Derivative instruments	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Other Liabilities
Other Liabilities:
Derivative instruments	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Designated as Hedging Instrument | Other Assets
Other Assets:
Derivative instruments	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Designated as Hedging Instrument | Other Liabilities
Other Liabilities:
Derivative instruments	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Not Designated as Hedging Instrument | Other Assets
Other Assets:
Derivative instruments	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Not Designated as Hedging Instrument | Other Liabilities
Other Liabilities:
Derivative instruments	0	0
Recurring | Fair Value Based on NAV as Practical Expedient
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	1,927,334	1,526,508
Recurring | Fair Value Based on NAV as Practical Expedient | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	1,927,334	1,526,508
Recurring | U.S. government and agency | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	736,043	510,245
Recurring | U.S. government and agency | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | U.S. government and agency | Significant Other Observable Inputs (Level 2) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	736,043	510,245
Recurring | U.S. government and agency | Significant Unobservable Inputs (Level 3) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | U.K. government | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	161,772	300,631
Recurring | U.K. government | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | U.K. government | Significant Other Observable Inputs (Level 2) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	161,772	300,631
Recurring | U.K. government | Significant Unobservable Inputs (Level 3) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Other government | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	702,857	793,810
Recurring | Other government | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Other government | Significant Other Observable Inputs (Level 2) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	702,857	793,810
Recurring | Other government | Significant Unobservable Inputs (Level 3) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Corporate | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	5,697,067	4,839,840
Recurring | Corporate | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Corporate | Significant Other Observable Inputs (Level 2) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	5,697,067	4,802,454
Recurring | Corporate | Significant Unobservable Inputs (Level 3) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	37,386
Recurring | Municipal | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	167,882	130,265
Recurring | Municipal | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Municipal | Significant Other Observable Inputs (Level 2) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	167,882	130,265
Recurring | Municipal | Significant Unobservable Inputs (Level 3) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Residential mortgage-backed | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	471,836	773,557
Recurring | Residential mortgage-backed | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Residential mortgage-backed | Significant Other Observable Inputs (Level 2) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	471,836	773,557
Recurring | Residential mortgage-backed | Significant Unobservable Inputs (Level 3) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Commercial mortgage-backed | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	900,029	713,063
Recurring | Commercial mortgage-backed | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Commercial mortgage-backed | Significant Other Observable Inputs (Level 2) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	900,029	705,674
Recurring | Commercial mortgage-backed | Significant Unobservable Inputs (Level 3) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	7,389
Recurring | Asset-backed | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	775,402	636,481
Recurring | Asset-backed | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Asset-backed | Significant Other Observable Inputs (Level 2) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	775,402	627,360
Recurring | Asset-backed | Significant Unobservable Inputs (Level 3) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	9,121
Recurring | Funds Held - Directly Managed | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	14,207	14,780
Recurring | Funds Held - Directly Managed | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Funds Held - Directly Managed | Significant Other Observable Inputs (Level 2) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	14,207	14,780
Recurring | Funds Held - Directly Managed | Significant Unobservable Inputs (Level 3) | Fixed maturity investments, trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Recurring | Publicly traded equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	327,875	138,415
Recurring | Publicly traded equity investments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	297,310	102,102
Recurring | Publicly traded equity investments | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	30,565	36,313
Recurring | Publicly traded equity investments | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	0	0
Recurring | Exchange-traded funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	133,047
Recurring | Exchange-traded funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	133,047
Recurring | Exchange-traded funds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	0
Recurring | Exchange-traded funds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	0
Recurring | Private equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	268,799	228,710
Recurring | Private equity funds | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	329,885	248,628
Recurring | Private equity funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	0	0
Recurring | Private equity funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | Private equity funds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	0	0
Recurring | Private equity funds | Significant Other Observable Inputs (Level 2) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | Private equity funds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	268,799	228,710
Recurring | Private equity funds | Significant Unobservable Inputs (Level 3) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | Private equity funds | Fair Value Based on NAV as Practical Expedient | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	329,885	248,628
Recurring | Hedge funds | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	1,121,904	852,584
Recurring | Hedge funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | Hedge funds | Significant Other Observable Inputs (Level 2) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | Hedge funds | Significant Unobservable Inputs (Level 3) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | Hedge funds | Fair Value Based on NAV as Practical Expedient | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	1,121,904	852,584
Recurring | Fixed income funds | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	481,039	403,858
Recurring | Fixed income funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | Fixed income funds | Significant Other Observable Inputs (Level 2) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	398,143	290,864
Recurring | Fixed income funds | Significant Unobservable Inputs (Level 3) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | Fixed income funds | Fair Value Based on NAV as Practical Expedient | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	82,896	112,994
Recurring | Equity funds | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	410,149	333,681
Recurring | Equity funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | Equity funds | Significant Other Observable Inputs (Level 2) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	111,040	100,440
Recurring | Equity funds | Significant Unobservable Inputs (Level 3) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | Equity funds | Fair Value Based on NAV as Practical Expedient | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	299,109	233,241
Recurring | CLO equities | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	87,555	39,052
Recurring | CLO equities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | CLO equities | Significant Other Observable Inputs (Level 2) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | CLO equities | Significant Unobservable Inputs (Level 3) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	87,555	39,052
Recurring | CLO equities | Fair Value Based on NAV as Practical Expedient | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | CLO equity funds | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	87,509	37,260
Recurring | CLO equity funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | CLO equity funds | Significant Other Observable Inputs (Level 2) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | CLO equity funds | Significant Unobservable Inputs (Level 3) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | CLO equity funds | Fair Value Based on NAV as Practical Expedient | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	87,509	37,260
Recurring | Other | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	6,379	9,313
Recurring | Other | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Recurring | Other | Significant Other Observable Inputs (Level 2) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	34	578
Recurring | Other | Significant Unobservable Inputs (Level 3) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	314	315
Recurring | Other | Fair Value Based on NAV as Practical Expedient | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	$ 6,031	8,420
Recurring | Private credit funds | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments		33,381
Recurring | Private credit funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments		0
Recurring | Private credit funds | Significant Other Observable Inputs (Level 2) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments		0
Recurring | Private credit funds | Significant Unobservable Inputs (Level 3) | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments		0
Recurring | Private credit funds | Fair Value Based on NAV as Practical Expedient | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments		$ 33,381

Fair Value Measurements - Recon

Fair Value Measurements - Reconciliation for Investments Measured At Fair Value on Recurring Basis Level 3 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning fair value	$ 321,973	$ 176,723
Purchases	90,805	304,387
Sales	(11,998)	(133,776)
Total realized and unrealized gains (losses)	970	(21,369)
Transfer into Level 3 from Level 2	27,923	46,633
Transfer out of Level 3 into Level 2	(73,005)	(50,625)
Ending fair value	356,668	321,973
Corporate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning fair value	37,386	67,178
Purchases	184	14,391
Sales	(3,520)	(65,700)
Total realized and unrealized gains (losses)	90	(57)
Transfer into Level 3 from Level 2	3,535	28,339
Transfer out of Level 3 into Level 2	(37,675)	(6,765)
Ending fair value	0	37,386
Residential mortgage-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning fair value	0	3,080
Purchases	0	0
Sales	0	(1,184)
Total realized and unrealized gains (losses)	(1)	(28)
Transfer into Level 3 from Level 2	102	1,795
Transfer out of Level 3 into Level 2	(101)	(3,663)
Ending fair value	0	0
Commercial mortgage-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning fair value	7,389	21,494
Purchases	0	3,749
Sales	(784)	(5,781)
Total realized and unrealized gains (losses)	64	(645)
Transfer into Level 3 from Level 2	1,515	4,897
Transfer out of Level 3 into Level 2	(8,184)	(16,325)
Ending fair value	0	7,389
Asset-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning fair value	9,121	27,892
Purchases	0	46,074
Sales	(5,088)	(49,020)
Total realized and unrealized gains (losses)	241	(1,843)
Transfer into Level 3 from Level 2	22,771	9,890
Transfer out of Level 3 into Level 2	(27,045)	(23,872)
Ending fair value	0	9,121
Privately-held Equities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning fair value	228,710	0
Purchases	33,713	227,000
Sales	(2,016)	0
Total realized and unrealized gains (losses)	8,392	(2)
Transfer into Level 3 from Level 2	0	1,712
Transfer out of Level 3 into Level 2	0	0
Ending fair value	268,799	228,710
Other Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning fair value	39,367	57,079
Purchases	56,908	13,173
Sales	(590)	(12,091)
Total realized and unrealized gains (losses)	(7,816)	(18,794)
Transfer into Level 3 from Level 2	0	0
Transfer out of Level 3 into Level 2	0	0
Ending fair value	$ 87,869	$ 39,367

Fair Value Measurements - Valua

Fair Value Measurements - Valuation Techniques and Inputs (Details) - Significant Unobservable Inputs (Level 3) $ in Millions	Dec. 31, 2019USD ($)
CLO equities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value	$ 87.6
CLO equities | Valuation Technique, Discounted Cash Flow [Member] | Collateral reinvestment coupon floor
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.01
CLO equities | Minimum | Valuation Technique, Consensus Pricing Model [Member] | Offered quotes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.14
CLO equities | Minimum | Valuation Technique, Discounted Cash Flow [Member] | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.10
CLO equities | Minimum | Valuation Technique, Discounted Cash Flow [Member] | Recovery rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.50
CLO equities | Minimum | Valuation Technique, Discounted Cash Flow [Member] | Prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.20
CLO equities | Maximum | Valuation Technique, Consensus Pricing Model [Member] | Offered quotes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.87
CLO equities | Maximum | Valuation Technique, Discounted Cash Flow [Member] | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.30
CLO equities | Maximum | Valuation Technique, Discounted Cash Flow [Member] | Recovery rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.70
CLO equities | Maximum | Valuation Technique, Discounted Cash Flow [Member] | Prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.30
CLO equities | Weighted Average | Valuation Technique, Consensus Pricing Model [Member] | Offered quotes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.48
CLO equities | Weighted Average | Valuation Technique, Discounted Cash Flow [Member] | Discount rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.195
CLO equities | Weighted Average | Valuation Technique, Discounted Cash Flow [Member] | Prepayment rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.25
Private equity funds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value	$ 268.8
Private equity funds | Minimum | Transactional value | Implied price at recent purchase transaction
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.135
Private equity funds | Maximum | Transactional value | Implied price at recent purchase transaction
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Alternative investments, measurement input	0.1385

Fair Value Measurements - Insur

Fair Value Measurements - Insurance Contracts - Fair Value Option (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reinsurance balances recoverable on paid and unpaid losses
Beginning fair value	$ 321,973	$ 176,723
Assumed business	90,805	304,387
Incurred losses and LAE:
Change in fair value	(970)	21,369
Ending fair value	356,668	321,973	$ 176,723
Net
Beginning fair value	2,134,464	1,252,445
Assumed business	9,218	1,517,281
Incurred losses and LAE:
Reduction in estimates of ultimate losses	(29,732)	(78,388)
Reduction in unallocated LAE	(19,915)	(20,656)
Change in fair value	117,181	6,664	30,256
Total incurred losses and LAE	67,534	(92,380)
Paid losses	(324,625)	(428,774)
Effect of exchange rate movements	39,013	(114,108)
Ending fair value	1,925,604	2,134,464	1,252,445
Components of Changes in Fair Value
Change in fair value	117,181	6,664	30,256
Reinsurance balances recoverable
Reinsurance balances recoverable on paid and unpaid losses
Beginning fair value	739,591	542,224
Assumed business	0	372,780
Incurred losses and LAE:
Reduction in estimates of ultimate losses	(2,958)	(30,041)
Reduction in unallocated LAE	0	0
Change in fair value	43,449	21,181
Net incurred losses and LAE	40,491	(8,860)
Paid losses	(92,145)	(148,175)
Effect of exchange rate movements	7,581	(18,378)
Ending fair value	695,518	739,591	542,224
Losses and LAE liabilities
Liability for losses and LAE
Beginning fair value	2,874,055	1,794,669
Assumed business	9,218	1,890,061
Incurred losses and LAE:
Reduction in estimates of ultimate losses	(32,690)	(108,429)
Reduction in unallocated LAE	(19,915)	(20,656)
Change in fair value	160,630	27,845
Net incurred losses and LAE	108,025	(101,240)
Paid losses	(416,770)	(576,949)
Effect of exchange rate movements	46,594	(132,486)
Ending fair value	2,621,122	2,874,055	1,794,669
Duration
Incurred losses and LAE:
Change in fair value	22,719	74,011	41,332
Components of Changes in Fair Value
Change in fair value	22,719	74,011	41,332
Corporate bond yield
Incurred losses and LAE:
Change in fair value	94,462	(71,031)	(11,076)
Components of Changes in Fair Value
Change in fair value	94,462	(71,031)	(11,076)
Risk cost of capital
Incurred losses and LAE:
Change in fair value	0	3,684	0
Components of Changes in Fair Value
Change in fair value	$ 0	$ 3,684	$ 0

Fair Value Measurements - Quant

Fair Value Measurements - Quantitative Information (Details) - Internal Model - Recurring	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Losses and LAE liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average cost of capital	8.50%	8.50%
Fair value inputs, duration	7 years 9 months 25 days	7 years 3 months 29 days
Reinsurance balances recoverable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Risk cost of capital	5.10%	5.00%
Fair value inputs, duration	8 years 8 months 4 days	7 years 11 months 23 days
Credit spread for non-performing risk | Losses and LAE liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit spread for non-performing risk	0.20%	0.20%

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values for Financial Instruments Carried At Cost (Details) - USD ($) $ in Thousands	Dec. 31, 2019	May 28, 2019	Dec. 31, 2018	Mar. 10, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of debt	$ 1,191,207		$ 861,539
Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of debt	$ 842,216		348,054
Senior Notes | Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	4.50%			4.50%
Carrying value of debt	$ 348,616		348,054
Fair value of debt	$ 362,500
Senior Notes | Senior Notes Due 2029
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	4.95%	4.95%
Carrying value of debt	$ 493,600		$ 0
Fair value of debt	$ 537,400

Premiums Written and Earned - S

Premiums Written and Earned - Schedule of Net Premiums Written and Earned (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effects of Reinsurance [Line Items]
Gross, premiums written									$ 1,103,393	$ 1,316,097	$ 1,068,453
Ceded, premiums written									(202,434)	(334,197)	(458,063)
Net, premiums written									900,959	981,900	610,390
Gross, premiums earned									1,422,058	1,225,711	1,047,287
Ceded, premiums earned									(267,197)	(330,136)	(434,166)
Net, premiums earned	$ 272,686	$ 270,325	$ 276,563	$ 335,287	$ 231,947	$ 264,597	$ 228,812	$ 170,219	1,154,861	895,575	613,121
Operating Segments | Non-life Run-off
Effects of Reinsurance [Line Items]
Gross, premiums written									(25,069)	(8,910)	14,102
Ceded, premiums written									(269)	(307)	(7,620)
Net, premiums written									(25,338)	(9,217)	6,482
Gross, premiums earned									197,009	25,230	23,950
Ceded, premiums earned									(28,513)	(15,803)	(9,788)
Net, premiums earned									168,496	9,427	14,162
Operating Segments | Atrium
Effects of Reinsurance [Line Items]
Gross, premiums written									192,373	171,494	153,472
Ceded, premiums written									(20,017)	(18,006)	(19,258)
Net, premiums written									172,356	153,488	134,214
Gross, premiums earned									182,678	164,428	152,278
Ceded, premiums earned									(18,619)	(18,113)	(17,531)
Net, premiums earned									164,059	146,315	134,747
Operating Segments | StarStone
Effects of Reinsurance [Line Items]
Gross, premiums written									917,555	1,121,135	895,160
Ceded, premiums written									(182,126)	(315,573)	(430,259)
Net, premiums written									735,429	805,562	464,901
Gross, premiums earned									1,021,827	1,010,816	865,159
Ceded, premiums earned									(219,901)	(295,857)	(405,756)
Net, premiums earned									801,926	714,959	459,403
Other
Effects of Reinsurance [Line Items]
Gross, premiums written									18,534	32,378	5,719
Ceded, premiums written									(22)	(311)	(926)
Net, premiums written									18,512	32,067	4,793
Gross, premiums earned									20,544	25,237	5,900
Ceded, premiums earned									(164)	(363)	(1,091)
Net, premiums earned									$ 20,380	$ 24,874	$ 4,809

Premiums Written and Earned - A

Premiums Written and Earned - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Insurance [Abstract]
Gross, premiums written	$ 1,103,393	$ 1,316,097	$ 1,068,453
Decrease in premiums written, gross	$ 212,700

Goodwill and Intangible Assets-

Goodwill and Intangible Assets- Schedule of Goodwill, Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Goodwill, Beginning balance	$ 114,807	$ 73,071
Acquired during the year		41,736
Goodwill, Ending balance	114,807	114,807	$ 73,071
Finite-lived Intangible Assets [Roll Forward]
Intangible assets with a definite life, Beginning balance	16,887	20,487
Acquired during the year		0
Amortization	(2,257)	(3,600)	(4,266)
Intangible assets with a definite life, Ending balance	14,630	16,887	20,487
Indefinite-lived Intangible Assets [Roll Forward]
Intangible assets with an indefinite life, Beginning balance	87,031	87,031
Acquired during the year		0
Intangible assets with an indefinite life, Ending balance	87,031	87,031	87,031
Intangible Assets [Roll Forward]
Total intangible assets, Beginning balance	103,918	107,518
Amortization	(2,257)	(3,600)	(4,266)
Total intangible assets, Ending balance	101,661	103,918	107,518
Goodwill and Intangible Assets [Roll Forward]
Goodwill and intangible assets, Beginning Balance	218,725	180,589
Acquired during the year		41,736
Amortization	(2,257)	(3,600)	(4,266)
Goodwill and intangible assets, Ending balance	$ 216,468	$ 218,725	$ 180,589

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	May 14, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Goodwill	$ 114,807,000	$ 114,807,000		$ 73,071,000
Impairment of goodwill	0
Non-life Run-off
Segment Reporting Information [Line Items]
Goodwill	62,959,000	62,959,000
Atrium Segment
Segment Reporting Information [Line Items]
Goodwill	38,848,000	38,848,000
StarStone
Segment Reporting Information [Line Items]
Goodwill	$ 13,000,000	$ 13,000,000
KaylaRe
Segment Reporting Information [Line Items]
Goodwill			$ 41,736,000

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Intangible asset amortization	$ 2,257	$ 3,600	$ 4,266
Minimum
Finite-Lived Intangible Assets [Line Items]
Intangible assets useful life	4 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Intangible assets useful life	15 years

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Summary of Gross Carrying Value, Accumulated Amortization and Net Carrying Value of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 42,000	$ 42,000
Accumulated Amortization	(27,370)	(25,113)
Total amortization	14,630	16,887	$ 20,487
Intangible assets with an indefinite life, Carrying Value	87,031	87,031	87,031
Total intangible assets	101,661	103,918	$ 107,518
Distribution channel
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	20,000	20,000
Accumulated Amortization	(8,111)	(6,776)
Total amortization	11,889	13,224
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	15,000	15,000
Accumulated Amortization	(15,000)	(14,778)
Total amortization	0	222
Brand
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	7,000	7,000
Accumulated Amortization	(4,259)	(3,559)
Total amortization	2,741	3,441
Atrium
Finite-Lived Intangible Assets [Line Items]
Total amortization	14,630	16,665
Intangible assets with an indefinite life, Carrying Value	63,131	63,131
Total intangible assets	77,761	79,796
Atrium | Distribution channel
Finite-Lived Intangible Assets [Line Items]
Total amortization	11,889	13,224
Atrium | Technology
Finite-Lived Intangible Assets [Line Items]
Total amortization	0	0
Atrium | Brand
Finite-Lived Intangible Assets [Line Items]
Total amortization	2,741	3,441
StarStone
Finite-Lived Intangible Assets [Line Items]
Total amortization	0	222
Intangible assets with an indefinite life, Carrying Value	23,900	23,900
Total intangible assets	23,900	24,122
StarStone | Distribution channel
Finite-Lived Intangible Assets [Line Items]
Total amortization	0	0
StarStone | Technology
Finite-Lived Intangible Assets [Line Items]
Total amortization	0	222
StarStone | Brand
Finite-Lived Intangible Assets [Line Items]
Total amortization	0	0
Lloyd’s syndicate capacity
Finite-Lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	37,031	37,031
Lloyd’s syndicate capacity | Atrium
Finite-Lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	33,031	33,031
Lloyd’s syndicate capacity | StarStone
Finite-Lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	4,000	4,000
Licenses
Finite-Lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	19,900	19,900
Licenses | Atrium
Finite-Lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	0	0
Licenses | StarStone
Finite-Lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	19,900	19,900
Management contract
Finite-Lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	30,100	30,100
Management contract | Atrium
Finite-Lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	30,100	30,100
Management contract | StarStone
Finite-Lived Intangible Assets [Line Items]
Intangible assets with an indefinite life, Carrying Value	$ 0	$ 0

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Summary of Estimated Amortization Expense of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
2020	$ 2,033
2021	2,033
2022	2,033
2023	1,975
2024	1,333
2025 and thereafter	5,223
Total amortization	14,630	$ 16,887	$ 20,487
Atrium
Segment Reporting Information [Line Items]
2020	2,033
2021	2,033
2022	2,033
2023	1,975
2024	1,333
2025 and thereafter	5,223
Total amortization	14,630	16,665
StarStone
Segment Reporting Information [Line Items]
2020	0
2021	0
2022	0
2023	0
2024	0
2025 and thereafter	0
Total amortization	$ 0	$ 222

Debt Obligations and Credit F_3

Debt Obligations and Credit Facilities - Amounts of Outstanding Debt and Accrued Interest (Details) - USD ($) $ in Thousands	Dec. 27, 2018	Aug. 16, 2018	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Line of Credit Facility [Line Items]
Carrying value of debt			$ 1,191,207				$ 861,539				$ 1,191,207	$ 861,539
Receipt of loans											1,070,502	1,132,507	$ 874,100
Repayment of loans											(742,574)	(914,319)	(912,140)
Interest expense on debt obligations											51,245	25,205	25,619
Amortization of debt issuance costs											953	537	416
Funds withheld balances and other											343	475	2,067
Total interest expense			13,519	$ 14,950	$ 13,036	$ 11,036	4,644	$ 4,640	$ 8,922	$ 8,011	52,541	26,217	$ 28,102
Senior Notes
Line of Credit Facility [Line Items]
Carrying value of debt			842,216				348,054				$ 842,216	348,054
Senior Notes | Senior Notes
Line of Credit Facility [Line Items]
Term											5 years
Carrying value of debt			348,616				348,054				$ 348,616	348,054
Senior Notes | Senior Notes Due 2029
Line of Credit Facility [Line Items]
Term											10 years
Carrying value of debt			493,600				0				$ 493,600	0
Loan facilities
Line of Credit Facility [Line Items]
Receipt of loans											1,070,500
Repayment of loans											$ (742,600)
Loan facilities | EGL Revolving Credit Facility
Line of Credit Facility [Line Items]
Term		5 years									5 years
Carrying value of debt			0				15,000				$ 0	15,000
Loan facilities | 2018 EGL Term Loan Facility
Line of Credit Facility [Line Items]
Term	3 years										3 years
Carrying value of debt			$ 348,991				$ 498,485				$ 348,991	$ 498,485
Repayment of loans											$ (150,000)

Debt Obligations and Credit F_4

Debt Obligations and Credit Facilities - Senior Notes (Details) - Senior Notes - USD ($)	May 28, 2019	Mar. 10, 2017	Dec. 31, 2019	Dec. 31, 2018
Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount		$ 350,000,000
Interest rate		4.50%	4.50%
Redemption price, percentage of principal amount		100.00%
Debt issuance costs		$ 2,900,000
Unamortized costs of debt			$ (1,400,000)	$ (1,900,000)
Senior Notes Due 2029
Debt Instrument [Line Items]
Aggregate principal amount	$ 500,000,000
Interest rate	4.95%		4.95%
Redemption price, percentage of principal amount	100.00%
Debt issuance costs	$ 6,800,000
Unamortized costs of debt			$ (6,400,000)

Debt Obligations and Credit F_5

Debt Obligations and Credit Facilities - EGL Revolving Credit Facility (Details)	Aug. 16, 2018USD ($)	Feb. 21, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Repayment of loans			$ (742,574,000)	$ (914,319,000)	$ (912,140,000)
Loan facilities
Debt Instrument [Line Items]
Repayment of loans			$ (742,600,000)
Loan facilities | EGL Revolving Credit Facility
Debt Instrument [Line Items]
Facility term	5 years		5 years
Maximum borrowing capacity	$ 600,000,000		$ 600,000,000
Increase in borrowing capacity, limit	$ 400,000,000
Available unutilized capacity			$ 600,000,000
Covenant compliance, consolidated indebtedness to total capitalization (not greater than)	0.35
Covenant compliance, net income (loss) threshold	$ 2,300,000,000
Covenant compliance, net income threshold percent	50.00%
Covenant compliance, percentage of proceeds of common stock issuance	50.00%
Subsequent Event | Loan facilities | EGL Revolving Credit Facility
Debt Instrument [Line Items]
Available unutilized capacity		$ 595,000,000
Repayment of loans		$ (5,000,000)

Debt Obligations and Credit F_6

Debt Obligations and Credit Facilities - EGL Term Loan Facilities (Details) - USD ($)	Dec. 27, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Repayment of loans		$ 742,574,000	$ 914,319,000	$ 912,140,000
Loan facilities
Debt Instrument [Line Items]
Repayment of loans		$ 742,600,000
Loan facilities | 2018 EGL Term Loan Facility
Debt Instrument [Line Items]
Facility term	3 years	3 years
Maximum borrowing capacity	$ 500,000,000
Increase in borrowing capacity, limit	$ 150,000,000
Repayment of loans		$ 150,000,000
Outstanding amount		349,000,000
Interest payment period	3 months
Debt issuance costs	$ 1,500,000
Unamortized costs of debt		$ (1,000,000)	$ (1,500,000)

Debt Obligations and Credit F_7

Debt Obligations and Credit Facilities - Unsecured Letters of Credit (Details) - USD ($)	Nov. 06, 2019	Dec. 31, 2019	Dec. 09, 2019	Dec. 06, 2019	Dec. 05, 2019	Feb. 12, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Cash and investments		$ 639,300,000
Maiden Facility Agreement
Debt Instrument [Line Items]
Proceeds from credit facility agreement		445,000,000
Loan facilities | FAL Facility
Debt Instrument [Line Items]
Facility increase option						$ 400,000,000
Letters of Credit | Loan facilities | FAL Facility
Debt Instrument [Line Items]
Maximum borrowing capacity						375,000,000
Increase in borrowing capacity, limit						$ 25,000,000
Term extension	1 year
Letters of Credit | Loan facilities | 2018 Facility Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 120,000,000	$ 170,000,000
Increase in borrowing capacity, limit				$ 60,000,000
Letters of credit		115,300,000					$ 78,400,000
Letters of Credit | Loan facilities | Maiden Facility Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity		760,000,000
Increase in borrowing capacity, limit			$ 40,000,000
Letters of credit		$ 608,000,000

Noncontrolling Interest - Redee

Noncontrolling Interest - Redeemable Noncontrolling Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of year	$ 458,543	$ 479,606
Capital contributions	13,127	55,377
Dividends paid	(11,556)	(3,852)
Net loss attributable to RNCI	(12,029)	(64,794)
Accumulated other comprehensive income attributable to RNCI	(116)	(240)
Change in redemption value of RNCI	(9,178)	(7,554)
Balance at end of year	$ 438,791	$ 458,543
Subsidiaries | Trident
Redeemable Noncontrolling Interest [Line Items]
Ownership interest held by noncontrolling owners	39.30%	39.30%
Subsidiaries | Dowling
Redeemable Noncontrolling Interest [Line Items]
Ownership interest held by noncontrolling owners	1.70%	1.70%

Noncontrolling Interest - Nonco

Noncontrolling Interest - Noncontrolling Interest (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Noncontrolling Interest [Abstract]
Noncontrolling interest	$ 14,168	$ 12,056

Share Capital - Voting Ordinary

Share Capital - Voting Ordinary Shares (Details)	Jan. 21, 2020shares	May 14, 2018shares	Dec. 31, 2019$ / sharesshares	Dec. 31, 2018vote$ / sharesshares
Class of Stock [Line Items]
Authorized share capital (shares) | shares			111,000,000	111,000,000
Ordinary shares, par value (dollars per share) | $ / shares			$ 1	$ 1
Preference shares (shares) | shares			45,000,000	45,000,000
Preferred shares, par value (dollars per share) | $ / shares			$ 1	$ 1
Voting ordinary shares
Class of Stock [Line Items]
Ordinary shares, par value (dollars per share) | $ / shares			1	$ 1
Number of votes | vote				1
Non-voting ordinary shares
Class of Stock [Line Items]
Ordinary shares, par value (dollars per share) | $ / shares			$ 1	$ 1
KaylaRe
Class of Stock [Line Items]
Number of Enstar ordinary shares issued (shares) | shares		2,007,017
Subsequent Event
Class of Stock [Line Items]
Treasury shares repurchased (shares) | shares	565,630

Share Capital - Non-Voting Shar

Share Capital - Non-Voting Shares (Details) - shares	May 14, 2018	Mar. 31, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Ordinary shares, issued (shares)				21,511,505	21,459,997
Ordinary shares, outstanding (shares)				21,511,505	21,459,997
Series C non-voting convertible ordinary shares
Class of Stock [Line Items]
Stock issued upon exercise of Warrants (shares)		66,520
Conversion ratio, issued upon conversion (shares)		1	1
Aggregate voting power of Company's issued share capital (percent) (not to exceed)		0.01%	0.01%
Stock issued upon conversion (shares)			192,485
Ordinary shares, issued (shares)				2,599,672	2,599,672
Ordinary shares, outstanding (shares)				2,599,672	2,599,672
Common Class B
Class of Stock [Line Items]
Ordinary shares, issued (shares)				0
Ordinary shares, outstanding (shares)				0
Common Class D
Class of Stock [Line Items]
Ordinary shares, issued (shares)				0
Ordinary shares, outstanding (shares)				0
Common Class E
Class of Stock [Line Items]
Ordinary shares, issued (shares)				910,010	910,010
Ordinary shares, outstanding (shares)				910,010	910,010
KaylaRe
Class of Stock [Line Items]
Number of Enstar Ordinary shares issued (in shares)	2,007,017
Common Class E | KaylaRe
Class of Stock [Line Items]
Number of Enstar Ordinary shares issued (in shares)	505,239

Share Capital - Warrants (Detai

Share Capital - Warrants (Details) - Common Class C	Dec. 31, 2019$ / sharesshares
Class of Stock [Line Items]
Warrants outstanding (shares) | shares	175,901
Warrants, exercise price (dollars per share) | $ / shares	$ 115

Share Capital - Preferred Share

Share Capital - Preferred Shares (Details) $ / shares in Units, $ in Thousands	Nov. 21, 2018USD ($)$ / sharesshares	Jun. 28, 2018USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)
Class of Stock [Line Items]
Preferred shares, par value (dollars per share)			$ 1	$ 1
Net proceeds from the issuance of preferred shares | $			$ 0	$ 495,357	$ 0
Series C Preferred Shares
Class of Stock [Line Items]
Preferred shares, issued (shares) | shares			388,571	388,571
Preferred shares, liquidation preference (dollars per share)			$ 0.001
Series D Preferred Stock
Class of Stock [Line Items]
Preferred shares, issued (shares) | shares			16,000	16,000
Dividend rate			7.00%
Series E Preferred Shares
Class of Stock [Line Items]
Preferred shares, issued (shares) | shares			4,400	4,400
Dividend rate			7.00%
Public Stock Offering | Series D Preferred Stock
Class of Stock [Line Items]
Preferred shares, liquidation preference (dollars per share)		$ 25,000
Consideration received on sale of stock | $		$ 400,000
Number of shares issued (shares) | shares		16,000
Dividend rate		7.00%
Depositary shares equivalent (shares) | shares		16,000,000
Depositary share, interest in preferred share		0.001
Preferred shares, par value (dollars per share)		$ 1
Liquidation preference per depositary share (dollars per share)		$ 25
Net proceeds from the issuance of preferred shares | $		$ 389,200
Public Stock Offering | Series E Preferred Shares
Class of Stock [Line Items]
Preferred shares, liquidation preference (dollars per share)	$ 25,000
Consideration received on sale of stock | $	$ 110,000
Number of shares issued (shares) | shares	4,400
Dividend rate	7.00%
Depositary shares equivalent (shares) | shares	4,400,000
Depositary share, interest in preferred share	0.001
Preferred shares, par value (dollars per share)	$ 1
Liquidation preference per depositary share (dollars per share)		$ 25
Net proceeds from the issuance of preferred shares | $	$ 106,100

Share Capital - Dividends on Pr

Share Capital - Dividends on Preferred Shares (Details) - USD ($) $ in Thousands	Nov. 21, 2018	Jun. 28, 2018	Feb. 21, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Total Dividends Paid in 2019				$ 35,914	$ 12,133	$ 0
Series D Preferred Shares
Class of Stock [Line Items]
Dividend rate				7.00%
Total Dividends Paid in 2019				$ 28,000	$ 12,100
Series E Preferred Shares
Class of Stock [Line Items]
Dividend rate				7.00%
Total Dividends Paid in 2019				$ 7,900
Public Stock Offering | Series D Preferred Shares
Class of Stock [Line Items]
Dividend rate		7.00%
Public Stock Offering | Series E Preferred Shares
Class of Stock [Line Items]
Dividend rate	7.00%
LIBOR | Public Stock Offering | Series D Preferred Shares
Class of Stock [Line Items]
Basis spread on variable rate		4.015%
Subsequent Event | Series D Preferred Shares
Class of Stock [Line Items]
Total Dividends Paid in 2019			$ 7,000
Subsequent Event | Series E Preferred Shares
Class of Stock [Line Items]
Total Dividends Paid in 2019			$ 1,900

Earnings Per Share - Comparison

Earnings Per Share - Comparison of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net earnings (loss) from continuing operations									$ 902,175	$ (162,354)	$ 300,465
Net earnings from discontinued operations, net of income taxes									0	0	10,993
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$ 193,839	$ 117,743	$ 231,842	$ 358,751	$ (113,423)	$ (15,965)	$ 8,244	$ (41,210)	$ 902,175	$ (162,354)	$ 311,458
Denominator:
Weighted-average ordinary shares outstanding — basic (shares)									21,482,617	20,698,310	19,388,621
Effect of dilutive securities:
Share-based compensation plans (shares)									227,878	129,746	62,732
Warrants (shares)									64,571	76,120	76,238
Weighted-average ordinary shares outstanding - diluted (shares)									21,775,066	20,904,176	19,527,591
Basic:
Net earnings (loss) from continuing operations (dollars per share)									$ 42	$ (7.84)	$ 15.50
Net earnings from discontinued operations (dollars per share)									0	0	0.56
Net earnings (loss) per ordinary share (dollars per share)	$ 9.02	$ 5.48	$ 10.79	$ 16.71	$ (5.29)	$ (0.74)	$ 0.40	$ (2.12)	42	(7.84)	16.06
Diluted:
Net earnings (loss) from continuing operations (dollars per share)									41.43	(7.84)	15.39
Net earnings from discontinued operations, net of income taxes (dollars per share)									0	0	0.56
Net earnings (loss) per ordinary share (dollars per share)	$ 8.89	$ 5.42	$ 10.70	$ 16.57	$ (5.29)	$ (0.74)	$ 0.40	$ (2.12)	$ 41.43	$ (7.84)	$ 15.95

Share-Based Compensation and _3

Share-Based Compensation and Pensions - Compensation Costs for Share-based Compensation Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation costs	$ 37,999	$ 10,670	$ 26,326
Restricted shares and restricted share units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation costs	6,564	7,641	7,302
Performance share units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation costs	23,582	1,968	5,832
Cash-settled stock appreciation rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation costs	2,575	(3,316)	8,875
Northshore incentive plan | Time-based restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation costs	3,652	2,792	3,156
StarStone incentive plan | Time-based restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation costs	223	0	0
Employee share purchase plan | Employee share purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation costs	411	430	403
Share-based compensation plans | Director | Deferred compensation and ordinary share plan for non-employee directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred compensation and ordinary share plan for non-employee directors	$ 992	$ 1,155	$ 758

Share-Based Compensation and _4

Share-Based Compensation and Pensions - Restricted Shares and Restricted Share Units (Details) - Restricted shares and restricted share units - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Number of Shares
Nonvested — January 1 (shares)	59,936
Granted (shares)	50,054
Vested (shares)	(42,462)
Forfeited (shares)	(2,956)
Nonvested — December 31 (shares)	64,572
Weighted-Average Share Price of Award
Nonvested - January 1 (dollars per share)	$ 191.89
Granted (dollars per share)	176.16
Vested (dollars per share)	189.98
Forfeited (dollars per share)	206.85
Nonvested - December 31 (dollars per share)	$ 180.49
Unrecognized compensation cost	$ 6
Unrecognized compensation cost, period of recognition	2 years 1 month 6 days

Share-Based Compensation and _5

Share-Based Compensation and Pensions - Performance Share Units (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended			36 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2019
Performance share units, FDBVPS
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSU's Granted at Target (shares)				186,186
Forfeited (shares)				(24,388)
Estimated Change in Multiplier (shares)				27,641
Nonvested Units (shares)	189,439			189,439	189,439
Number of Shares
Granted (shares)				186,186
Increase for above target vest (shares)				27,641
Forfeited (shares)				(24,388)
Nonvested — December 31 (shares)	189,439			189,439
Performance share units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
PSU's Granted at Target (shares)	36,616
Forfeited (shares)	(13,845)
Estimated Change in Multiplier (shares)	27,641
Nonvested Units (shares)	206,949	159,168		206,949	206,949
Number of Shares
Nonvested — January 1 (shares)	159,168
Granted (shares)	36,616
Increase for above target vest (shares)	27,641
Vested (shares)	(2,631)
Forfeited (shares)	(13,845)
Nonvested — December 31 (shares)	206,949	159,168		206,949
Weighted-Average Share Price of Award
Nonvested - January 1 (dollars per share)	$ 190.77
Granted (dollars per share)	166.42
Increase for above target vest (dollars per share)	188.62
Vested (dollars per share)	195.60
Forfeited (dollars per share)	198.37
Nonvested - December 31 (dollars per share)	$ 185.61	$ 190.77		$ 185.61
Unrecognized compensation cost					$ 7.9
Unrecognized compensation cost, period of recognition	1 year 6 months 3 days
Performance Target One | Performance share units | Minimum
Performance Multiplier Levels Per Award Agreements
Share settlement percentage	100.00%
Performance Target One | Performance share units | Maximum
Performance Multiplier Levels Per Award Agreements
Share settlement percentage	150.00%
2017 Awards | Performance share units, FDBVPS | Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSU's Granted at Target (shares)			36,321
Forfeited (shares)			(12,176)
Estimated Change in Multiplier (shares)			9,560
Nonvested Units (shares)	33,705			33,705	33,705
Change in FDBVPS (3 - year)
Threshold	20.00%
Target	30.00%
Maximum	40.00%
Performance Multiplier Levels Per Award Agreements
Threshold	50.00%
Target	100.00%
Maximum	150.00%
Performance Criteria: Average Annual Operating ROE
Performance multiplier	139.00%	50.00%	100.00%
Number of Shares
Granted (shares)			36,321
Increase for above target vest (shares)			9,560
Forfeited (shares)			(12,176)
Nonvested — December 31 (shares)	33,705			33,705
2017 Awards | Performance share units, FDBVPS | Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSU's Granted at Target (shares)			91,875
Forfeited (shares)			0
Estimated Change in Multiplier (shares)			18,081
Nonvested Units (shares)	109,956			109,956	109,956
Change in FDBVPS (3 - year)
Threshold	30.30%
Target	35.65%
Maximum	41.00%
Performance Multiplier Levels Per Award Agreements
Threshold	50.00%
Target	100.00%
Maximum	150.00%
Performance Criteria: Average Annual Operating ROE
Performance multiplier	120.00%	50.00%	100.00%
Number of Shares
Granted (shares)			91,875
Increase for above target vest (shares)			18,081
Forfeited (shares)			0
Nonvested — December 31 (shares)	109,956			109,956
2017 Awards | Performance Target Two | Performance share units, FDBVPS | Minimum
Performance Multiplier Levels Per Award Agreements
Share settlement percentage	50.00%
2017 Awards | Performance Target Two | Performance share units, FDBVPS | Maximum
Performance Multiplier Levels Per Award Agreements
Share settlement percentage	100.00%
2018 Awards | Performance share units, FDBVPS
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSU's Granted at Target (shares)		39,682
Forfeited (shares)		(11,414)
Estimated Change in Multiplier (shares)		0
Nonvested Units (shares)	28,268			28,268	28,268
Change in FDBVPS (3 - year)
Threshold	25.00%
Target	32.50%
Maximum	40.00%
Performance Multiplier Levels Per Award Agreements
Threshold	50.00%
Target	100.00%
Maximum	150.00%
Performance Criteria: Average Annual Operating ROE
Performance multiplier	100.00%	50.00%
Number of Shares
Granted (shares)		39,682
Increase for above target vest (shares)		0
Forfeited (shares)		(11,414)
Nonvested — December 31 (shares)	28,268			28,268
2018 Awards | Performance Target Two | Performance share units | Minimum
Performance Multiplier Levels Per Award Agreements
Share settlement percentage	50.00%
2018 Awards | Performance Target Two | Performance share units | Maximum
Performance Multiplier Levels Per Award Agreements
Share settlement percentage	100.00%
2019 Awards | Performance share units, FDBVPS
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSU's Granted at Target (shares)	18,308
Forfeited (shares)	(798)
Estimated Change in Multiplier (shares)	0
Nonvested Units (shares)	17,510			17,510	17,510
Change in FDBVPS (3 - year)
Threshold	20.00%
Target	30.00%
Maximum	40.00%
Performance Multiplier Levels Per Award Agreements
Threshold	60.00%
Target	100.00%
Maximum	150.00%
Number of Shares
Granted (shares)	18,308
Increase for above target vest (shares)	0
Forfeited (shares)	(798)
Nonvested — December 31 (shares)	17,510			17,510
2019 Awards | Performance share units, FDBVPS | Tranche One
Performance Criteria: Average Annual Operating ROE
Performance multiplier	100.00%
2019 Awards | Performance share units, Average Operating ROE
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSU's Granted at Target (shares)	18,308
Forfeited (shares)	(798)
Estimated Change in Multiplier (shares)	0
Nonvested Units (shares)	17,510			17,510	17,510
Performance Multiplier Levels Per Award Agreements
Threshold	60.00%
Target	100.00%
Maximum	150.00%
Performance Criteria: Average Annual Operating ROE
Threshold	9.60%
Target	12.00%
Maximum	14.40%
Number of Shares
Granted (shares)	18,308
Increase for above target vest (shares)	0
Forfeited (shares)	(798)
Nonvested — December 31 (shares)	17,510			17,510
2019 Awards | Performance share units, Average Operating ROE | Tranche Two
Performance Criteria: Average Annual Operating ROE
Performance multiplier	100.00%
2019 Awards | Performance Target Two | Performance share units | Minimum
Performance Multiplier Levels Per Award Agreements
Share settlement percentage	60.00%
2019 Awards | Performance Target Two | Performance share units | Maximum
Performance Multiplier Levels Per Award Agreements
Share settlement percentage	100.00%

Share-Based Compensation and _6

Share-Based Compensation and Pensions - Cash-Settled Stock Appreciation Rights (Detail) - Cash-settled stock appreciation rights - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Balance, beginning of year, Number of SARs (shares)	109,081
Exercised, Number of SARs (shares)	(19,854)
Balance, end of year, Number of SARs (shares)	89,227	109,081
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Balance, beginning of year, Weighted Average Exercise Price of SARs (dollars per share)	$ 142.37
Exercised, Weighted Average Exercise Price of SARs (dollars per share)	138.07
Balance, end of year, Weighted Average Exercise Price of SARs (dollars per share)	$ 143.33	$ 142.37
Balance, end of year, Weighted Average Remaining Contractual Term (in years)	2 years 4 months 20 days
Balance, end of year, Aggregate Intrinsic Value	$ 6,133
Closing price per share, ordinary shares (dollars per share)	$ 206.86
Unrecognized compensation cost	$ 100
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Weighted-average fair value per SAR (dollars per share)	$ 76.03	$ 45.85	$ 75.38
Weighted-average volatility	19.75%	18.94%	19.44%
Weighted-average risk-free interest rate	1.64%	2.72%	1.65%
Dividend yield	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise period	4 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise period	10 years

Share-Based Compensation and _7

Share-Based Compensation and Pensions - Joint Share Ownership Plan (Details) - Joint Share Ownership Plan - USD ($)	Jan. 20, 2023	Jan. 21, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (shares)			0
Hurdle price per share (dollars per share)			$ 266
Percentage of award subject to performance condition			20.00%
Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued, price per share (dollars per share)		$ 205.89
Chief Executive Officer | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares subscribed (shares)		565,630
Vesting period		3 years
Grant date fair value		$ 13,600,000
Scenario, Forecast
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volume weighted average price per share, days	10 days
Consecutive trading days	10 days

Share-Based Compensation and _8

Share-Based Compensation and Pensions - Other Share-Based Compensation Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Northshore incentive plan | Time-based restricted shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Unrecognized compensation cost	$ 0.9
Unrecognized compensation cost, period of recognition	4 months 9 days
Northshore incentive plan | Minimum | Time-based restricted shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Vesting period	2 years
Northshore incentive plan | Maximum | Time-based restricted shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Vesting period	3 years
StarStone incentive plan | Time-based restricted shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Unrecognized compensation cost	$ 1.8
Unrecognized compensation cost, period of recognition	2 years
StarStone incentive plan | Minimum | Time-based restricted shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Vesting period	2 years
StarStone incentive plan | Maximum | Time-based restricted shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Vesting period	3 years
Deferred compensation and ordinary share plan for non-employee directors | Director | Share-based compensation plans
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Restricted share units credited to the accounts of non-employee directors (shares)	5,976	5,691	3,852
Employee share purchase plan | Employee share purchase plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Discount rate from market price	15.00%
Maximum subscription rate	15.00%
Stock issued to employees (shares)	15,269	14,183	12,401

Share-Based Compensation and _9

Share-Based Compensation and Pensions - Pension Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plans	$ 11,798	$ 11,434	$ 12,247
Defined benefit plan	684	2,243	1,988
Total pension expense	12,482	13,677	$ 14,235
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, unfunded liability	8,900	8,400
Accrued liability, defined benefit plan	$ 8,900	$ 8,400

Income Taxation - Additional In

Income Taxation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Bermuda income taxes, statutory rate	0.00%	0.00%	0.00%
Valuation allowance	$ 117,390,000	$ 212,113,000
Increase (decrease) in valuation allowance	(94,700,000)		$ (7,400,000)
Utilized deferred tax asset	69,700,000
Deferred tax asset valuation allowance release	25,000,000
Unrecognized tax benefits	0	0	0
Accrued interest and penalties related to unrecognized tax benefits	$ 0	$ 0	0
Decrease in deferred tax assets			$ 63,800,000

Income Taxation - Earnings befo

Income Taxation - Earnings before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Domestic (Bermuda)	$ 576,339	$ (232,743)	$ 167,263
Foreign	356,317	14,347	147,148
EARNINGS (LOSS) BEFORE INCOME TAXES	$ 932,656	$ (218,396)	$ 314,411

Income Taxation - Tax Expense f

Income Taxation - Tax Expense for Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Domestic (Bermuda)									$ 0	$ 0	$ 0
Foreign									18,433	(3,632)	10,299
Total current tax expense									18,433	(3,632)	10,299
Deferred:
Domestic (Bermuda)									0	0	0
Foreign									(13,996)	(2,492)	(16,694)
Total deferred tax expense									(13,996)	(2,492)	(16,694)
Total income tax expense (benefit) on continuing operations	$ (22,427)	$ 14,597	$ 7,518	$ 4,749	$ (10,688)	$ 746	$ 3,646	$ 172	$ 4,437	$ (6,124)	$ (6,395)

Income Taxation - Reconciliatio

Income Taxation - Reconciliation of Earnings before Income Taxes Computed by Applying Effective Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Earnings (loss) before income tax	$ 932,656	$ (218,396)	$ 314,411
Bermuda income taxes at statutory rate	0.00%	0.00%	0.00%
Foreign income tax rate differential	8.60%	0.70%	13.10%
Change in valuation allowance	(8.20%)	(0.30%)	(34.90%)
Effect of change in foreign (U.S.) tax rate	0.00%	0.00%	20.30%
U.S. base erosion and anti-abuse tax	0.50%	(0.60%)	0.00%
Other	(0.40%)	3.00%	(0.50%)
Effective tax rate	0.50%	2.80%	(2.00%)

Income Taxation - Components of

Income Taxation - Components of Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 159,436	$ 183,633
Insurance reserves	14,104	18,677
Unearned premiums	7,131	11,314
Lloyd's underwriting losses taxable in future periods	0	6,201
Provisions for bad debt	6,172	2,594
Unrealized losses on investments	0	5,160
Defendant asbestos and environmental liabilities	140,000	0
Other deferred tax assets	0	183
Gross deferred tax assets	326,843	227,762
Valuation allowance	(117,390)	(212,113)
Deferred tax assets	209,453	15,649
Deferred tax liabilities:
Unrealized gains on investments	(10,107)	0
Lloyd's underwriting profit taxable in future periods	(8,852)	0
Deferred policy acquisition cost	(8,267)	0
Other deferred tax liabilities	(27,317)	(16,067)
Deferred tax liabilities	(54,543)	(16,067)
Net deferred tax asset	$ 154,910
Net deferred tax liability		$ (418)

Income Taxation - Deferred Tax

Income Taxation - Deferred Tax Ending Balance (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Net Deferred Tax Asset	$ 154,910
Net Deferred Tax Liability		$ (418)
United States
Segment Reporting Information [Line Items]
Net Deferred Tax Asset	169,891	5,151
United Kingdom
Segment Reporting Information [Line Items]
Net Deferred Tax Liability	(16,074)	(8,377)
Other
Segment Reporting Information [Line Items]
Net Deferred Tax Asset	$ 1,093	$ 2,808

Income Taxation - Net Operating

Income Taxation - Net Operating Loss Carryforwards (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Tax effect of operating loss carryforward	$ 159,436	$ 183,633
Foreign Tax Authority | United States
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	513,476
Tax effect of operating loss carryforward	107,830
Foreign Tax Authority | United Kingdom
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	224,150
Tax effect of operating loss carryforward	38,106
Foreign Tax Authority | Other
Operating Loss Carryforwards [Line Items]
Operating loss carryforward	52,484
Tax effect of operating loss carryforward	$ 13,500

Related Party Transactions - St

Related Party Transactions - Stone Point Capital LLC (Details) $ in Thousands	Oct. 01, 2019USD ($)	Apr. 01, 2019USD ($)	Oct. 01, 2018USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Jul. 31, 2012shares	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Nov. 06, 2013general_partner
Related Party Transaction [Line Items]
Assumed business													$ 1,586,307	$ 1,772,104	$ 1,525,703
Adverse development cover	$ 59,000
Redeemable noncontrolling interest				$ 438,791				$ 458,543					438,791	458,543	479,606
Investments in funds				2,524,420				1,957,757					2,524,420	1,957,757
Available-for-sale, at fair value				2,041,724				151,609					2,041,724	151,609
Equities, at fair value				729,721				367,125					729,721	367,125
Cash and cash equivalents				703,085				602,096					703,085	602,096	955,150
Other assets				744,608				707,469					744,608	707,469
Other liabilities				464,014				468,129					464,014	468,129
Net realized and unrealized gains (losses)				152,664	$ 148,185	$ 269,711	$ 460,791	(158,213)	$ (57,223)	$ (54,418)	$ (143,030)		1,031,351	(412,884)	190,334
Net earnings (loss)				197,864	$ 126,559	$ 238,054	$ 365,742	(149,378)	$ (22,321)	$ (145)	$ (40,428)		928,219	(212,272)	331,799
Affiliated entity
Related Party Transaction [Line Items]
Investments in funds				1,741,400									1,741,400
Trident | Affiliated entity
Related Party Transaction [Line Items]
Voting ordinary shares acquired (shares) | shares												1,635,986
Number of newly elected board of directors | general_partner																1
Number of general partners | general_partner																4
Redeemable noncontrolling interest				420,499				439,428					420,499	439,428
Equities, at fair value				96,800									96,800
StonePoint And Affiliated Entities
Related Party Transaction [Line Items]
Equities, at fair value				121,794				57,319					121,794	57,319
Cash and cash equivalents				54,080				11,739					54,080	11,739
Other assets				10				5,216					10	5,216
Other liabilities				4,710				4,240					4,710	4,240
Interest income													8,733	7,424	5,990
Net realized and unrealized gains (losses)													26,631	207	24,684
Net earnings (loss)													35,364	7,631	$ 30,674
Starstone
Related Party Transaction [Line Items]
Assumed business	189,400
Reinsurance premium consideration	$ 189,400
Short-term Investments
Related Party Transaction [Line Items]
Available-for-sale, at fair value				128,335				0					128,335	0
Fixed maturity investments, trading				51,490				114,116					51,490	114,116
Short-term Investments | StonePoint And Affiliated Entities
Related Party Transaction [Line Items]
Available-for-sale, at fair value				1,431				0					1,431	0
CLO equities
Related Party Transaction [Line Items]
Investments in funds				87,555				39,052					87,555	39,052
CLO equities | StonePoint And Affiliated Entities
Related Party Transaction [Line Items]
Investments in funds				32,560				15,372					32,560	15,372
Fixed Maturities
Related Party Transaction [Line Items]
Available-for-sale, at fair value				1,913,389				151,609					1,913,389	151,609
Fixed maturity investments, trading				6,346,329				7,248,793					6,346,329	7,248,793
Fixed Maturities | StonePoint And Affiliated Entities
Related Party Transaction [Line Items]
Available-for-sale, at fair value				160,303				0					160,303	0
Fixed maturity investments, trading				269,131				176,193					269,131	176,193
Hedge funds
Related Party Transaction [Line Items]
Investments in funds				1,121,904				852,584					1,121,904	852,584
Hedge funds | StonePoint And Affiliated Entities
Related Party Transaction [Line Items]
Investments in funds				18,993				19,535					18,993	19,535
Fixed income funds
Related Party Transaction [Line Items]
Investments in funds				481,039				403,858					481,039	403,858
Fixed income funds | StonePoint And Affiliated Entities
Related Party Transaction [Line Items]
Investments in funds				381,449				324,561					381,449	324,561
Private equity funds
Related Party Transaction [Line Items]
Investments in funds				329,885				248,628					329,885	248,628
Equities, at fair value				268,799				228,710					268,799	228,710
Private equity funds | StonePoint And Affiliated Entities
Related Party Transaction [Line Items]
Investments in funds				34,858				52,925					34,858	52,925
CLO equity funds
Related Party Transaction [Line Items]
Investments in funds				87,509				37,260					87,509	37,260
CLO equity funds | StonePoint And Affiliated Entities
Related Party Transaction [Line Items]
Investments in funds				87,509				37,260					87,509	37,260
Private Debt | StonePoint And Affiliated Entities
Related Party Transaction [Line Items]
Investments in funds				16,312				10,387					16,312	10,387
Real estate fund | StonePoint And Affiliated Entities
Related Party Transaction [Line Items]
Investments in funds				$ 18,106				8,025					$ 18,106	8,025
Stone Point | Affiliated entity
Related Party Transaction [Line Items]
Voting ordinary shares acquired, percent				9.10%									9.10%
Agreement period													90 days
North Bay Shareholders | North Bay
Related Party Transaction [Line Items]
Payments to acquire investments		$ 48,000	$ 135,000
Trident | North Bay
Related Party Transaction [Line Items]
Payments to acquire investments			$ 53,100
Mitchell International | Affiliated entity
Related Party Transaction [Line Items]
Investments in funds				$ 25,000				$ 25,000					$ 25,000	$ 25,000

Related Party Transactions - Ka

Related Party Transactions - KaylaRe (Details) - USD ($) $ in Thousands	May 14, 2018	Dec. 15, 2016	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	May 13, 2018	Dec. 31, 2016
Related Party Transaction [Line Items]
Ownership percentage			47.40%				47.40%				47.40%	47.40%
Fee income due to Enstar Limited												$ 1,453	$ 2,679
Transactions under KaylaRe-StarStone QS:
Ceded, premiums earned											$ (267,197)	(330,136)	(434,166)
Net incurred losses and LAE			$ 121,416	$ 222,417	$ 216,338	$ 312,404	$ 187,698	$ 153,974	$ 92,819	$ 19,534	872,575	454,025	193,551
Acquisition costs			$ 95,026	$ 50,282	$ 66,855	$ 93,788	$ 55,106	$ 54,242	$ 53,334	$ 30,108	$ 305,951	192,790	96,906
KaylaRe
Related Party Transaction [Line Items]
Initial capital raise		$ 620,000
KaylaRe | Starstone
Related Party Transaction [Line Items]
Percentage reinsured of certain businesses											35.00%
KaylaRe | Fitzwilliam | Subsidiaries
Related Party Transaction [Line Items]
Ceded reinsurance receivables															$ 177,200
KaylaRe Transactions With Starstone
Transactions under KaylaRe-StarStone QS:
Ceded, premiums earned												(52,651)	(234,079)
Net incurred losses and LAE												31,654	155,433
Acquisition costs												18,774	99,500
KaylaRe Transactions With Fitzwilliam | Subsidiaries
Transactions under Fitzwilliam reinsurance agreement:
Profit Commission												0	18,843
Affiliated entity | KaylaRe
Transactions under Fitzwilliam reinsurance agreement:
Total net earnings (loss)												$ (770)	$ 42,376
KaylaRe
Related Party Transaction [Line Items]
Ownership percentage														48.20%
KaylaRe
Related Party Transaction [Line Items]
Number of Enstar ordinary shares issued (shares)	2,007,017
Ordinary Shares | KaylaRe
Related Party Transaction [Line Items]
Number of Enstar ordinary shares issued (shares)	1,501,778
Ordinary Shares | KaylaRe | Hillhouse
Related Party Transaction [Line Items]
Number of Enstar ordinary shares issued (shares)	1,204,353
Ordinary Shares | KaylaRe | Trident
Related Party Transaction [Line Items]
Number of Enstar ordinary shares issued (shares)	285,986
Series E non-voting convertible ordinary shares | KaylaRe
Related Party Transaction [Line Items]
Number of Enstar ordinary shares issued (shares)	505,239
Series E non-voting convertible ordinary shares | KaylaRe | Hillhouse
Related Party Transaction [Line Items]
Number of Enstar ordinary shares issued (shares)	505,239
Series E non-voting convertible ordinary shares | KaylaRe | Minority Shareholder
Related Party Transaction [Line Items]
Number of Enstar ordinary shares issued (shares)	11,439

Related Party Transactions - Hi

Related Party Transactions - Hillhouse (Details) - USD ($) $ in Thousands	Jan. 01, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Investments in funds		$ 2,524,420	$ 1,957,757
Ownership %		47.40%	47.40%
Purchase of investment		$ 69,213	$ 155,440	$ 0
Affiliated entity
Related Party Transaction [Line Items]
Investments in funds		$ 1,741,400
Hillhouse Affiliates | Affiliated entity
Related Party Transaction [Line Items]
Voting ordinary shares acquired, percent		9.70%
Economic ownership percentage		17.00%
Hillhouse
Related Party Transaction [Line Items]
Investments in funds		$ 1,151,601	845,066
Hillhouse | Affiliated entity
Related Party Transaction [Line Items]
Investments in funds		155,377	35,641
Management fees		89,000
Hillhouse | KaylaRe | Affiliated entity
Related Party Transaction [Line Items]
Investments in funds		$ 327,799	75,192
Hillhouse InRe Fund, L.P. | Fixed Income Securities | Affiliated entity
Related Party Transaction [Line Items]
Percent of funds invested		18.00%
Hillhouse InRe Fund, L.P. | North American Equities | Affiliated entity
Related Party Transaction [Line Items]
Percent of funds invested		6.00%
Hillhouse InRe Fund, L.P. | International Equities | Affiliated entity
Related Party Transaction [Line Items]
Percent of funds invested		96.00%
Hillhouse InRe Fund, L.P. | Financing, Derivatives And Other Items | Affiliated entity
Related Party Transaction [Line Items]
Percent of funds invested		(20.00%)
InRe Fund | Hillhouse | Affiliated entity
Related Party Transaction [Line Items]
Investments in funds		$ 918,633	678,420
Other funds | Hillhouse | Affiliated entity
Related Party Transaction [Line Items]
Investments in funds		$ 232,968	$ 166,646
Subsequent Event | Hillhouse | EnhanzedRe
Related Party Transaction [Line Items]
Purchase of investment	$ 54,000

Related Party Transactions - Mo

Related Party Transactions - Monument (Details) $ in Thousands, € in Millions	12 Months Ended			39 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2019USD ($)	May 31, 2019USD ($)	May 31, 2019EUR (€)	Aug. 29, 2017USD ($)	Aug. 29, 2017EUR (€)
Related Party Transaction [Line Items]
Investment in common and preferred shares	$ 69,213	$ 155,440	$ 0
Ownership percentage	47.40%	47.40%		47.40%
Loss on sale of subsidiary	$ 0	$ 0	16,349
Cumulative CTA adjustment	0	0	(20,751)
Policy benefits for life contracts		105,100
Equity method investments	$ 326,277	$ 204,507		$ 326,277
Laguna | Not discontinued operations, disposed of by sale
Related Party Transaction [Line Items]
Loss on sale of subsidiary			16,300
Cumulative CTA adjustment			$ (6,300)
Monument | Laguna | Not discontinued operations, disposed of by sale | Affiliated entity
Related Party Transaction [Line Items]
Consideration received							$ 30,800	€ 25.6
Monument
Related Party Transaction [Line Items]
Investment in common and preferred shares				$ 26,600
Ownership percentage	26.60%	26.60%		26.60%
Equity method investments	$ 60,598	$ 42,193		$ 60,598
Transfer Of Life Assurance Policies | Subsidiary of Monument
Related Party Transaction [Line Items]
Policy benefits for life contracts					$ 99,100	€ 88.8
Assets related to future policy benefits					$ (101,600)	€ (91.1)

Related Party Transactions - Cl

Related Party Transactions - Clear Spring (Details) - USD ($) $ in Thousands	Jan. 01, 2017	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Capitalized amount	$ 56,000
Ownership percentage		47.40%				47.40%				47.40%	47.40%
Equity method investments		$ 326,277				$ 204,507				$ 326,277	$ 204,507
Balances under ceding quota share:
Reinsurance recoverable		2,379,890				2,029,663				2,379,890	2,029,663
Balances under assuming quota share:
Losses and LAE		10,429,238				9,409,504				10,429,238	9,409,504	$ 7,398,088	$ 5,987,867
Unearned premiums		746,775				842,618				746,775	842,618
Funds held by reinsured companies		408,735				321,267				408,735	321,267
Amounts under ceding quota share:
Ceded, premiums earned										(267,197)	(330,136)	(434,166)
Net incurred losses and LAE										47,018	0	0
Acquisition costs		95,026	$ 50,282	$ 66,855	$ 93,788	55,106	$ 54,242	$ 53,334	$ 30,108	305,951	192,790	96,906
Amounts under assuming quota share:
Premiums earned, assumed										273,807	236,182	142,161
Net incurred losses and loss adjustment expenses		$ 121,416	$ 222,417	$ 216,338	$ 312,404	187,698	$ 153,974	$ 92,819	$ 19,534	$ 872,575	454,025	193,551
Equity method investee | Clear Spring
Related Party Transaction [Line Items]
Ownership percentage		20.00%								20.00%
Balances under ceding quota share:
Reinsurance recoverable		$ 22,812				23,718				$ 22,812	23,718
Prepaid reinsurance premiums		51				13,821				51	13,821
Ceded other liabilities		3,616				14,153				3,616	14,153
Ceded acquisition costs		21				3,233				21	3,233
Affiliated entity | Clear Spring
Amounts under assuming quota share:
Total income impact										(6,616)	(3,334)	2,625
Starstone | Clear Spring
Related Party Transaction [Line Items]
Equity method investments		10,645				10,070				10,645	10,070
Percentage reinsured of certain businesses	33.30%
Starstone | Cavello Bay
Related Party Transaction [Line Items]
Percentage reinsured of certain businesses	25.00%
Starstone | Affiliated entity | Clear Spring
Amounts under ceding quota share:
Ceded, premiums earned										(14,994)	(29,520)	(14,256)
Net incurred losses and LAE										6,567	18,143	9,533
Acquisition costs										356	7,035	6,718
Cavello Bay | Clear Spring
Balances under assuming quota share:
Losses and LAE		6,135				5,778				6,135	5,778
Unearned premiums		13				3,455				13	3,455
Funds held by reinsured companies		$ 8,611				$ 10,242				8,611	10,242
Cavello Bay | Affiliated entity | Clear Spring
Amounts under ceding quota share:
Acquisition costs										92	1,836	1,753
Amounts under assuming quota share:
Premiums earned, assumed										3,749	7,380	3,564
Net incurred losses and loss adjustment expenses										$ (2,202)	$ (4,536)	$ (1,181)

Related Party Transactions - Am

Related Party Transactions - AmTrust (Details) - USD ($)	1 Months Ended		3 Months Ended								12 Months Ended
	Dec. 31, 2019	Nov. 30, 2018	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Investment in common and preferred shares											$ 69,213,000	$ 155,440,000	$ 0
Other income												1,453,000	2,679,000
Net investment income			$ 79,376,000	$ 85,472,000	$ 77,732,000	$ 78,696,000	$ 68,453,000	$ 69,430,000	$ 66,469,000	$ 66,319,000	321,276,000	270,671,000	208,789,000
Net realized and unrealized gains (losses)			152,664,000	$ 148,185,000	$ 269,711,000	$ 460,791,000	(158,213,000)	$ (57,223,000)	$ (54,418,000)	$ (143,030,000)	1,031,351,000	(412,884,000)	$ 190,334,000
Evergreen Parent L.P. | Affiliated entity
Related Party Transaction [Line Items]
Investment in common and preferred shares	$ 25,900,000	$ 200,000,000
Ownership of equity interest		8.50%
Other income												3,300,000
AmTrust Financial Services, Inc. | Affiliated entity
Related Party Transaction [Line Items]
Indirect investment	$ 240,115,000		$ 240,115,000				$ 200,000,000				240,115,000	200,000,000
Net investment income											7,700,000	300,000
Net realized and unrealized gains (losses)											$ 10,100,000	$ 0
Evergreen Parent L.P. | Trident Pine | Affiliated entity
Related Party Transaction [Line Items]
Ownership of equity interest		21.80%
AmTrust Financial Services, Inc. | Affiliated entity
Related Party Transaction [Line Items]
Voting ordinary shares acquired, percent		45.00%

Related Party Transactions - Ci

Related Party Transactions - Citco (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Net additional subscriptions		$ 796,918	$ 901,071	$ 109,885
Investments in funds		2,524,420	1,957,757
Affiliated entity
Related Party Transaction [Line Items]
Investments in funds		$ 1,741,400
Citco | Trident | Affiliated entity
Related Party Transaction [Line Items]
Net additional subscriptions	$ 50,000
Voting ordinary shares acquired, percent		3.40%
Citco
Related Party Transaction [Line Items]
Investments in funds		$ 51,742	$ 50,812

Related Party Transactions - En

Related Party Transactions - EnhanzedRe (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Equity method investments	$ 326,277				$ 204,507				$ 326,277	$ 204,507
Ownership percentage	47.40%				47.40%				47.40%	47.40%
Balances under ceding quota share:
Insurance balances payables	$ 373,180				$ 388,086				$ 373,180	$ 388,086
Reinsurance recoverable	2,379,890				2,029,663				2,379,890	2,029,663
Funds held	408,735				321,267				408,735	321,267
Other assets	744,608				707,469				744,608	707,469
Amounts under ceding quota share:
Acquisition costs	95,026	$ 50,282	$ 66,855	$ 93,788	55,106	$ 54,242	$ 53,334	$ 30,108	305,951	192,790	$ 96,906
Other income										1,453	2,679
Net earnings (loss)	197,864	$ 126,559	$ 238,054	$ 365,742	(149,378)	$ (22,321)	$ (145)	$ (40,428)	928,219	(212,272)	$ 331,799
EnhanzedRe | Enstar
Related Party Transaction [Line Items]
Equity method investments	$ 154,100								$ 154,100
Ownership percentage	47.40%								47.40%
Uncalled amount of investment	$ 68,700								$ 68,700
EnhanzedRe | Allianz
Related Party Transaction [Line Items]
Ownership percentage	24.90%								24.90%
EnhanzedRe | Hillhouse
Related Party Transaction [Line Items]
Ownership percentage	27.70%								27.70%
EnhanzedRe
Related Party Transaction [Line Items]
Equity method investments	$ 182,856				$ 94,800				$ 182,856	$ 94,800
Ownership percentage	47.40%				47.40%				47.40%	47.40%
EnhanzedRe | Affiliated entity
Related Party Transaction [Line Items]
Equity method investments	$ 470,000								$ 470,000
Balances under ceding quota share:
Insurance balances payables	1,443								1,443
Reinsurance recoverable	59,601								59,601
Funds held	50,089								50,089
Other assets	$ 1,033								1,033
Amounts under ceding quota share:
Acquisition costs									73
Other income									749
Net earnings (loss)									$ 822
EnhanzedRe | Zurich
Related Party Transaction [Line Items]
Percentage ceded									10.00%

Dividend Restrictions and Sta_3

Dividend Restrictions and Statutory Financial Information - Parent Company Dividends (Details)	12 Months Ended
	Dec. 31, 2019
Series D Preferred Shares
Statutory Accounting Practices [Line Items]
Dividend rate	7.00%
Series E Preferred Shares
Statutory Accounting Practices [Line Items]
Dividend rate	7.00%
Bermuda
Statutory Accounting Practices [Line Items]
Target statutory capital and surplus percent	120.00%

Dividend Restrictions and Sta_4

Dividend Restrictions and Statutory Financial Information - Subsidiary Statutory Financial Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Bermuda
Statutory Accounting Practices [Line Items]
Required	$ 2,138,395	$ 1,591,991
Actual	4,016,663	3,701,825
Statutory Income	643,683	29,486	$ 390,752
U.K.
Statutory Accounting Practices [Line Items]
Required	837,104	654,721
Actual	1,532,751	715,448
Statutory Income	154,644	(52,936)	77,900
U.S.
Statutory Accounting Practices [Line Items]
Required	364,507	392,394
Actual	861,379	660,470
Statutory Income	121,406	(75,005)	(5,065)
Europe
Statutory Accounting Practices [Line Items]
Required	94,334	239,582
Actual	229,344	431,863
Statutory Income	11,816	(17,611)	(4,245)
Australia
Statutory Accounting Practices [Line Items]
Required	18,110	22,535
Actual	37,815	26,882
Statutory Income	$ 4,847	$ 1,761	$ (874)

Dividend Restrictions and Sta_5

Dividend Restrictions and Statutory Financial Information - Subsidiary Statutory Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)syndicate	Dec. 31, 2018USD ($)
Statutory Accounting Practices [Line Items]
Restricted net assets of consolidated subsidiaries	$ 3,500
Number of syndicates | syndicate	3
Bermuda
Statutory Accounting Practices [Line Items]
Minimum liquidity ratio percent (not less than)	75.00%
Maximum percentage reduction in total statutory capital without prior approval of Bermuda regulator (percent) (or more)	15.00%
Minimum solvency requirement	$ 1,900	$ 2,100
United Kingdom
Statutory Accounting Practices [Line Items]
Minimum capital requirements	695.6	60.7
United States
Statutory Accounting Practices [Line Items]
Minimum levels of risk-based capital	488.3	359.6
Liechtenstein
Statutory Accounting Practices [Line Items]
Minimum solvency requirement	$ 119	$ 133.9

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Feb. 12, 2019
Concentration Risk [Line Items]
Funds held by reinsured companies	$ 408,735,000	$ 321,267,000
Renewal lease term	5 years
Termination period	1 year
Rent expense		11,300,000	$ 9,500,000
Minimum
Concentration Risk [Line Items]
Remaining lease terms	1 year
Maximum
Concentration Risk [Line Items]
Remaining lease terms	37 years
Limited Parental Guarantee
Concentration Risk [Line Items]
Total parental guarantees	$ 1,031,500,000	$ 614,500,000
FAL Facility | Loan facilities
Concentration Risk [Line Items]
Facility increase option				$ 400,000,000
FAL Facility | Loan facilities | Letters of Credit
Concentration Risk [Line Items]
Maximum borrowing capacity				375,000,000
Increase in borrowing capacity, limit				$ 25,000,000
Reinsurer concentration risk | Reinsurance balances recoverable
Concentration Risk [Line Items]
Funds held by reinsured companies	1,000,000,000
United States
Concentration Risk [Line Items]
Exposure to government	1,082,200,000
Private equity funds
Concentration Risk [Line Items]
Commitments, unfunded	482,300,000
Equity Method Investments
Concentration Risk [Line Items]
Commitments, unfunded	$ 93,100,000

Commitments and Contingencies_2

Commitments and Contingencies - Leases - Lease Cost (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 13,627
Sublease income	(542)
Total lease cost	$ 13,085

Commitments and Contingencies_3

Commitments and Contingencies - Leases - Cash Flow Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Operating cash flow information:
Cash paid for amounts included in the measurement of lease liabilities	$ 11,129
Non-cash activity:
Right-of-use assets obtained in exchange for lease obligations	$ 57,536

Commitments and Contingencies_4

Commitments and Contingencies - Leases - Balance Sheet Information (Details) $ in Thousands	Dec. 31, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
Right-of-use assets	$ 46,747
Current lease liabilities	11,403
Non-current lease liabilities	$ 34,785

Commitments and Contingencies_5

Commitments and Contingencies - Leases - Lease Terms (Details)	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Weighted-average remaining lease term	6 years 3 months 18 days
Weighted-average discount rate	6.30%

Commitments and Contingencies_6

Commitments and Contingencies - Leases - Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2020	$ 13,663
2021	9,854
2022	8,103
2023	7,044
2024	5,358
2025 and beyond	13,119
Total lease payments	57,141
Less: Imputed interest	(10,953)
Present value of lease liabilities	$ 46,188
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019		$ 9,510
2020		10,754
2021		9,772
2022		7,500
2023		6,592
2024 and beyond		21,276
Total		$ 65,404

Segment Information - Additiona

Segment Information - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019Segment
Segment Reporting [Abstract]
Number of segments	3

Segment Information - Summary o

Segment Information - Summary of Operations by Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Gross premiums written									$ 1,103,393	$ 1,316,097	$ 1,068,453
Net premiums written									900,959	981,900	610,390
Net premiums earned	$ 272,686	$ 270,325	$ 276,563	$ 335,287	$ 231,947	$ 264,597	$ 228,812	$ 170,219	1,154,861	895,575	613,121
Net incurred losses and LAE	(121,416)	(222,417)	(216,338)	(312,404)	(187,698)	(153,974)	(92,819)	(19,534)	(872,575)	(454,025)	(193,551)
Life and Annuity Policy Benefits	2,199	0	(2,194)	(96)	(786)	(423)	160	46	(91)	(1,003)	(4,015)
Acquisition costs	(95,026)	(50,282)	(66,855)	(93,788)	(55,106)	(54,242)	(53,334)	(30,108)	(305,951)	(192,790)	(96,906)
Operating expenses									(334,837)	(333,234)	(285,237)
Underwriting income (loss)									(358,593)	(85,477)	33,412
Net investment income	79,376	85,472	77,732	78,696	68,453	69,430	66,469	66,319	321,276	270,671	208,789
Net realized and unrealized gains (losses)	152,664	148,185	269,711	460,791	(158,213)	(57,223)	(54,418)	(143,030)	1,031,351	(412,884)	190,334
Fees and commission income	9,007	6,587	6,178	6,681	11,455	6,950	8,352	8,331	28,453	35,088	66,103
Other income	19,502	826	11,030	5,812	34,267	8,226	(9,351)	1,943	37,170	35,085	22,605
Corporate expenses									(138,249)	(74,141)	(150,748)
Interest income (expense)									(52,541)	(26,217)	(28,102)
Net foreign exchange gains (losses)	(12,189)	13,631	2,587	3,850	(1,279)	(1,040)	5,519	(5,868)	7,879	(2,668)	(17,537)
Loss on sale of subsidiary									0	0	(16,349)
EARNINGS (LOSS) BEFORE INCOME TAXES	163,715	123,453	227,859	361,719	(168,554)	(24,892)	(12,144)	(54,953)	876,746	(260,543)	308,507
Income tax benefit (expense)	22,427	(14,597)	(7,518)	(4,749)	10,688	(746)	(3,646)	(172)	(4,437)	6,124	6,395
Earnings from equity method investments	11,722	17,703	17,713	8,772	8,488	3,317	15,645	14,697	55,910	42,147	5,904
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS									928,219	(212,272)	320,806
Net earnings from discontinued operations, net of income taxes									0	0	10,993
NET EARNINGS (LOSS)	197,864	126,559	238,054	365,742	(149,378)	(22,321)	(145)	(40,428)	928,219	(212,272)	331,799
Net loss (earnings) attributable to noncontrolling interest	4,900	109	2,713	2,148	42,955	11,489	8,389	(782)	9,870	62,051	(20,341)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	202,764	126,668	240,767	367,890	(106,423)	(10,832)	8,244	(41,210)	938,089	(150,221)	311,458
Dividends on preferred shares	(8,925)	(8,925)	(8,925)	(9,139)	(7,000)	(5,133)	0	0	(35,914)	(12,133)	0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$ 193,839	$ 117,743	$ 231,842	$ 358,751	$ (113,423)	$ (15,965)	$ 8,244	$ (41,210)	902,175	(162,354)	311,458
Non-life Run-off
Segment Reporting Information [Line Items]
Net incurred losses and LAE									(51,625)	306,067	190,674
Atrium
Segment Reporting Information [Line Items]
Net incurred losses and LAE									$ (77,276)	$ (69,810)	$ (69,419)
Underwriting ratios:
Loss ratio									47.10%	47.70%	51.50%
Acquisition expense ratio									34.70%	34.60%	35.40%
Other operating expense ratio									8.80%	12.20%	13.00%
Combined ratio									90.60%	94.50%	99.90%
StarStone
Segment Reporting Information [Line Items]
Net incurred losses and LAE									$ (727,636)	$ (673,383)	$ (314,806)
Underwriting ratios:
Loss ratio									90.70%	94.20%	68.50%
Acquisition expense ratio									21.80%	18.90%	10.50%
Other operating expense ratio									15.10%	22.00%	29.50%
Combined ratio									127.60%	135.10%	108.50%
Operating Segments | Non-life Run-off
Segment Reporting Information [Line Items]
Gross premiums written									$ (25,069)	$ (8,910)	$ 14,102
Net premiums written									(25,338)	(9,217)	6,482
Net premiums earned									168,496	9,427	14,162
Net incurred losses and LAE									(51,625)	306,067	190,674
Life and Annuity Policy Benefits									0	0	0
Acquisition costs									(73,642)	(4,006)	(328)
Operating expenses									(199,756)	(158,731)	(132,235)
Underwriting income (loss)									(156,527)	152,757	72,273
Net investment income									275,236	226,287	166,678
Net realized and unrealized gains (losses)									968,350	(381,712)	179,545
Fees and commission income									18,293	16,466	43,849
Other income									34,809	35,978	21,157
Corporate expenses									(70,689)	(39,093)	(101,592)
Interest income (expense)									(62,055)	(30,616)	(28,970)
Net foreign exchange gains (losses)									9,918	2,534	(7,347)
Loss on sale of subsidiary											0
EARNINGS (LOSS) BEFORE INCOME TAXES									1,017,335	(17,399)	345,593
Income tax benefit (expense)									(7,250)	3,581	6,990
Earnings from equity method investments									56,128	42,147	5,904
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS											358,487
Net earnings from discontinued operations, net of income taxes											0
NET EARNINGS (LOSS)									1,066,213	28,329	358,487
Net loss (earnings) attributable to noncontrolling interest									(6,409)	(3,107)	(14,687)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED									1,059,804	25,222
Dividends on preferred shares									0	0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS									1,059,804	25,222	343,800
Operating Segments | Atrium
Segment Reporting Information [Line Items]
Gross premiums written									192,373	171,494	153,472
Net premiums written									172,356	153,488	134,214
Net premiums earned									164,059	146,315	134,747
Net incurred losses and LAE									(77,276)	(69,810)	(69,419)
Life and Annuity Policy Benefits									0	0	0
Acquisition costs									(56,956)	(50,646)	(47,688)
Operating expenses									(14,452)	(17,777)	(17,444)
Underwriting income (loss)									15,375	8,082	196
Net investment income									7,049	5,686	4,218
Net realized and unrealized gains (losses)									6,195	(3,251)	1,117
Fees and commission income									10,160	18,622	22,788
Other income									140	162	230
Corporate expenses									(13,825)	(6,921)	(12,142)
Interest income (expense)									0	0	(559)
Net foreign exchange gains (losses)									(504)	(3,394)	(5,060)
Loss on sale of subsidiary											0
EARNINGS (LOSS) BEFORE INCOME TAXES									24,590	18,986	10,788
Income tax benefit (expense)									(4,033)	(3,732)	(1,593)
Earnings from equity method investments									0	0	0
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS											9,195
Net earnings from discontinued operations, net of income taxes											0
NET EARNINGS (LOSS)									20,557	15,254	9,195
Net loss (earnings) attributable to noncontrolling interest									(8,432)	(6,257)	(3,772)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED									12,125	8,997
Dividends on preferred shares									0	0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS									12,125	8,997	5,423
Operating Segments | StarStone
Segment Reporting Information [Line Items]
Gross premiums written									917,555	1,121,135	895,160
Net premiums written									735,429	805,562	464,901
Net premiums earned									801,926	714,959	459,403
Net incurred losses and LAE									(727,636)	(673,383)	(314,806)
Life and Annuity Policy Benefits									0	0	0
Acquisition costs									(174,711)	(135,452)	(48,012)
Operating expenses									(120,629)	(156,726)	(135,558)
Underwriting income (loss)									(221,050)	(250,602)	(38,973)
Net investment income									47,401	35,973	27,706
Net realized and unrealized gains (losses)									50,957	(17,672)	16,613
Fees and commission income									0	0	632
Other income									338	(541)	570
Corporate expenses									(7,790)	0	0
Interest income (expense)									(475)	(624)	(1,902)
Net foreign exchange gains (losses)									(1,538)	(2,856)	(926)
Loss on sale of subsidiary											0
EARNINGS (LOSS) BEFORE INCOME TAXES									(132,157)	(236,322)	3,720
Income tax benefit (expense)									6,931	6,327	988
Earnings from equity method investments									(218)	0	0
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS											4,708
Net earnings from discontinued operations, net of income taxes											0
NET EARNINGS (LOSS)									(125,444)	(229,995)	4,708
Net loss (earnings) attributable to noncontrolling interest									24,711	71,415	(1,882)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED									(100,733)	(158,580)
Dividends on preferred shares									0	0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS									(100,733)	(158,580)	2,826
Other
Segment Reporting Information [Line Items]
Gross premiums written									18,534	32,378	5,719
Net premiums written									18,512	32,067	4,793
Net premiums earned									20,380	24,874	4,809
Net incurred losses and LAE									(16,038)	(16,899)	0
Life and Annuity Policy Benefits									(91)	(1,003)	(4,015)
Acquisition costs									(642)	(2,686)	(878)
Operating expenses									0	0	0
Underwriting income (loss)									3,609	4,286	(84)
Net investment income									(8,410)	2,725	10,187
Net realized and unrealized gains (losses)									5,849	(10,249)	(6,941)
Fees and commission income									0	0	(1,166)
Other income									1,883	(514)	648
Corporate expenses									(45,945)	(28,127)	(37,014)
Interest income (expense)									9,989	5,023	3,329
Net foreign exchange gains (losses)									3	1,048	(4,204)
Loss on sale of subsidiary											(16,349)
EARNINGS (LOSS) BEFORE INCOME TAXES									(33,022)	(25,808)	(51,594)
Income tax benefit (expense)									(85)	(52)	10
Earnings from equity method investments									0	0	0
NET EARNINGS (LOSS) FROM CONTINUING OPERATIONS											(51,584)
Net earnings from discontinued operations, net of income taxes											10,993
NET EARNINGS (LOSS)									(33,107)	(25,860)	(40,591)
Net loss (earnings) attributable to noncontrolling interest									0	0	0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED									(33,107)	(25,860)
Dividends on preferred shares									(35,914)	(12,133)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS									$ (69,021)	$ (37,993)	$ (40,591)

Segment Information - Gross Pre

Segment Information - Gross Premiums Written by Geographical Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Gross, premiums written	$ 1,103,393	$ 1,316,097	$ 1,068,453
United States
Segment Reporting Information [Line Items]
Gross, premiums written	643,109
United Kingdom
Segment Reporting Information [Line Items]
Gross, premiums written	128,144
Europe
Segment Reporting Information [Line Items]
Gross, premiums written	134,188
Asia
Segment Reporting Information [Line Items]
Gross, premiums written	81,425
Rest of World
Segment Reporting Information [Line Items]
Gross, premiums written	$ 116,527
Geographic concentration risk | Gross premiums written
Segment Reporting Information [Line Items]
Gross premiums written (percent)	100.00%
Geographic concentration risk | Gross premiums written | United States
Segment Reporting Information [Line Items]
Gross premiums written (percent)	58.20%
Geographic concentration risk | Gross premiums written | United Kingdom
Segment Reporting Information [Line Items]
Gross premiums written (percent)	11.60%
Geographic concentration risk | Gross premiums written | Europe
Segment Reporting Information [Line Items]
Gross premiums written (percent)	12.20%
Geographic concentration risk | Gross premiums written | Asia
Segment Reporting Information [Line Items]
Gross premiums written (percent)	7.40%
Geographic concentration risk | Gross premiums written | Rest of World
Segment Reporting Information [Line Items]
Gross premiums written (percent)	10.60%
Operating Segments | Non-life Run-off
Segment Reporting Information [Line Items]
Gross, premiums written	$ (25,069)	(8,910)	14,102
Operating Segments | Atrium
Segment Reporting Information [Line Items]
Gross, premiums written	192,373	171,494	153,472
Operating Segments | StarStone
Segment Reporting Information [Line Items]
Gross, premiums written	917,555	1,121,135	895,160
Operating Segments | United States | Non-life Run-off
Segment Reporting Information [Line Items]
Gross, premiums written	(25,012)
Operating Segments | United States | Atrium
Segment Reporting Information [Line Items]
Gross, premiums written	102,199
Operating Segments | United States | StarStone
Segment Reporting Information [Line Items]
Gross, premiums written	548,683
Operating Segments | United Kingdom | Non-life Run-off
Segment Reporting Information [Line Items]
Gross, premiums written	350
Operating Segments | United Kingdom | Atrium
Segment Reporting Information [Line Items]
Gross, premiums written	12,972
Operating Segments | United Kingdom | StarStone
Segment Reporting Information [Line Items]
Gross, premiums written	114,822
Operating Segments | Europe | Non-life Run-off
Segment Reporting Information [Line Items]
Gross, premiums written	(265)
Operating Segments | Europe | Atrium
Segment Reporting Information [Line Items]
Gross, premiums written	17,677
Operating Segments | Europe | StarStone
Segment Reporting Information [Line Items]
Gross, premiums written	115,481
Operating Segments | Asia | Non-life Run-off
Segment Reporting Information [Line Items]
Gross, premiums written	(48)
Operating Segments | Asia | Atrium
Segment Reporting Information [Line Items]
Gross, premiums written	5,700
Operating Segments | Asia | StarStone
Segment Reporting Information [Line Items]
Gross, premiums written	75,773
Operating Segments | Rest of World | Non-life Run-off
Segment Reporting Information [Line Items]
Gross, premiums written	(94)
Operating Segments | Rest of World | Atrium
Segment Reporting Information [Line Items]
Gross, premiums written	53,825
Operating Segments | Rest of World | StarStone
Segment Reporting Information [Line Items]
Gross, premiums written	$ 62,796
Operating Segments | Geographic concentration risk | Gross premiums written | Non-life Run-off
Segment Reporting Information [Line Items]
Gross premiums written (percent)	100.00%
Operating Segments | Geographic concentration risk | Gross premiums written | Atrium
Segment Reporting Information [Line Items]
Gross premiums written (percent)	100.00%
Operating Segments | Geographic concentration risk | Gross premiums written | StarStone
Segment Reporting Information [Line Items]
Gross premiums written (percent)	100.00%
Operating Segments | Geographic concentration risk | Gross premiums written | United States | Non-life Run-off
Segment Reporting Information [Line Items]
Gross premiums written (percent)	99.70%
Operating Segments | Geographic concentration risk | Gross premiums written | United States | Atrium
Segment Reporting Information [Line Items]
Gross premiums written (percent)	53.10%
Operating Segments | Geographic concentration risk | Gross premiums written | United States | StarStone
Segment Reporting Information [Line Items]
Gross premiums written (percent)	59.80%
Operating Segments | Geographic concentration risk | Gross premiums written | United Kingdom | Non-life Run-off
Segment Reporting Information [Line Items]
Gross premiums written (percent)	(1.40%)
Operating Segments | Geographic concentration risk | Gross premiums written | United Kingdom | Atrium
Segment Reporting Information [Line Items]
Gross premiums written (percent)	6.70%
Operating Segments | Geographic concentration risk | Gross premiums written | United Kingdom | StarStone
Segment Reporting Information [Line Items]
Gross premiums written (percent)	12.50%
Operating Segments | Geographic concentration risk | Gross premiums written | Europe | Non-life Run-off
Segment Reporting Information [Line Items]
Gross premiums written (percent)	1.10%
Operating Segments | Geographic concentration risk | Gross premiums written | Europe | Atrium
Segment Reporting Information [Line Items]
Gross premiums written (percent)	9.20%
Operating Segments | Geographic concentration risk | Gross premiums written | Europe | StarStone
Segment Reporting Information [Line Items]
Gross premiums written (percent)	12.60%
Operating Segments | Geographic concentration risk | Gross premiums written | Asia | Non-life Run-off
Segment Reporting Information [Line Items]
Gross premiums written (percent)	0.20%
Operating Segments | Geographic concentration risk | Gross premiums written | Asia | Atrium
Segment Reporting Information [Line Items]
Gross premiums written (percent)	3.00%
Operating Segments | Geographic concentration risk | Gross premiums written | Asia | StarStone
Segment Reporting Information [Line Items]
Gross premiums written (percent)	8.30%
Operating Segments | Geographic concentration risk | Gross premiums written | Rest of World | Non-life Run-off
Segment Reporting Information [Line Items]
Gross premiums written (percent)	0.40%
Operating Segments | Geographic concentration risk | Gross premiums written | Rest of World | Atrium
Segment Reporting Information [Line Items]
Gross premiums written (percent)	28.00%
Operating Segments | Geographic concentration risk | Gross premiums written | Rest of World | StarStone
Segment Reporting Information [Line Items]
Gross premiums written (percent)	6.80%
Other
Segment Reporting Information [Line Items]
Gross, premiums written	$ 18,534	$ 32,378	$ 5,719
Other | United States
Segment Reporting Information [Line Items]
Gross, premiums written	17,239
Other | United Kingdom
Segment Reporting Information [Line Items]
Gross, premiums written	0
Other | Europe
Segment Reporting Information [Line Items]
Gross, premiums written	1,295
Other | Asia
Segment Reporting Information [Line Items]
Gross, premiums written	0
Other | Rest of World
Segment Reporting Information [Line Items]
Gross, premiums written	$ 0
Other | Geographic concentration risk | Gross premiums written
Segment Reporting Information [Line Items]
Gross premiums written (percent)	100.00%
Other | Geographic concentration risk | Gross premiums written | United States
Segment Reporting Information [Line Items]
Gross premiums written (percent)	93.00%
Other | Geographic concentration risk | Gross premiums written | United Kingdom
Segment Reporting Information [Line Items]
Gross premiums written (percent)	0.00%
Other | Geographic concentration risk | Gross premiums written | Europe
Segment Reporting Information [Line Items]
Gross premiums written (percent)	7.00%
Other | Geographic concentration risk | Gross premiums written | Asia
Segment Reporting Information [Line Items]
Gross premiums written (percent)	0.00%
Other | Geographic concentration risk | Gross premiums written | Rest of World
Segment Reporting Information [Line Items]
Gross premiums written (percent)	0.00%

Segment Information - Summary_2

Segment Information - Summary of Company's Assets by Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 19,363,315	$ 16,556,270
Operating Segments | Non-life Run-off
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	15,775,409	13,362,749
Operating Segments | Atrium
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	580,405	591,722
Operating Segments | StarStone
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	3,522,353	3,416,132
Other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ (514,852)	$ (814,333)

Unaudited Condensed Quarterly_3

Unaudited Condensed Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
INCOME
Net premiums earned	$ 272,686	$ 270,325	$ 276,563	$ 335,287	$ 231,947	$ 264,597	$ 228,812	$ 170,219	$ 1,154,861	$ 895,575	$ 613,121
Fees and commission income	9,007	6,587	6,178	6,681	11,455	6,950	8,352	8,331	28,453	35,088	66,103
Net investment income	79,376	85,472	77,732	78,696	68,453	69,430	66,469	66,319	321,276	270,671	208,789
Net realized and unrealized gains (losses)	152,664	148,185	269,711	460,791	(158,213)	(57,223)	(54,418)	(143,030)	1,031,351	(412,884)	190,334
Other income (losses)	19,502	826	11,030	5,812	34,267	8,226	(9,351)	1,943	37,170	35,085	22,605
Total income	533,235	511,395	641,214	887,267	187,909	291,980	239,864	103,782	2,573,111	823,535	1,100,952
EXPENSES
Net incurred losses and loss adjustment expenses	121,416	222,417	216,338	312,404	187,698	153,974	92,819	19,534	872,575	454,025	193,551
Life and annuity policy benefits	(2,199)	0	2,194	96	786	423	(160)	(46)	91	1,003	4,015
Acquisition costs	95,026	50,282	66,855	93,788	55,106	54,242	53,334	30,108	305,951	192,790	96,906
General and administrative expenses	129,569	113,924	117,519	112,074	106,950	102,553	102,612	95,260	473,086	407,375	435,985
Interest expense	13,519	14,950	13,036	11,036	4,644	4,640	8,922	8,011	52,541	26,217	28,102
Net foreign exchange (gains) losses	12,189	(13,631)	(2,587)	(3,850)	1,279	1,040	(5,519)	5,868	(7,879)	2,668	17,537
Total expenses	369,520	387,942	413,355	525,548	356,463	316,872	252,008	158,735	1,696,365	1,084,078	792,445
EARNINGS (LOSS) BEFORE INCOME TAXES	163,715	123,453	227,859	361,719	(168,554)	(24,892)	(12,144)	(54,953)	876,746	(260,543)	308,507
Income tax benefit (expense)	22,427	(14,597)	(7,518)	(4,749)	10,688	(746)	(3,646)	(172)	(4,437)	6,124	6,395
Earnings from equity method investments	11,722	17,703	17,713	8,772	8,488	3,317	15,645	14,697	55,910	42,147	5,904
NET EARNINGS (LOSS)	197,864	126,559	238,054	365,742	(149,378)	(22,321)	(145)	(40,428)	928,219	(212,272)	331,799
Net loss (earnings) attributable to noncontrolling interest	4,900	109	2,713	2,148	42,955	11,489	8,389	(782)	9,870	62,051	(20,341)
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	202,764	126,668	240,767	367,890	(106,423)	(10,832)	8,244	(41,210)	938,089	(150,221)	311,458
Dividends on preferred shares	(8,925)	(8,925)	(8,925)	(9,139)	(7,000)	(5,133)	0	0	(35,914)	(12,133)	0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$ 193,839	$ 117,743	$ 231,842	$ 358,751	$ (113,423)	$ (15,965)	$ 8,244	$ (41,210)	$ 902,175	$ (162,354)	$ 311,458
Earnings Loss) per ordinary share attributable to Enstar Group Limited:
Basic (dollars per share)	$ 9.02	$ 5.48	$ 10.79	$ 16.71	$ (5.29)	$ (0.74)	$ 0.40	$ (2.12)	$ 42	$ (7.84)	$ 16.06
Diluted (dollars per share)	$ 8.89	$ 5.42	$ 10.70	$ 16.57	$ (5.29)	$ (0.74)	$ 0.40	$ (2.12)	$ 41.43	$ (7.84)	$ 15.95

Schedule I - Summary of Inves_2

Schedule I - Summary of Investments Other Than Investments in Related Parties (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	$ 10,416,611
Fair Value	10,748,664
Amount at which shown in the balance sheet	10,748,664
Equity investments	729,721	$ 367,125
Fair value of other investments in funds or companies owned by or affiliated with related parties	2,524,420	1,957,757
Stone Point
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fixed maturity investments	15,100
Affiliated entity
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair value of other investments in funds or companies owned by or affiliated with related parties	1,741,400
Affiliated entity | Trident
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Equity investments	96,800
AmTrust Financial Services, Inc.
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Indirect investment	240,100
Equities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	312,407
Fair Value	367,812
Amount at which shown in the balance sheet	367,812
Other investments, at fair value
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	783,032
Fair Value	783,032
Amount at which shown in the balance sheet	783,032
Funds Held - Directly Managed
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	7,284,703
Fair Value	7,562,076
Amount at which shown in the balance sheet	7,562,076
Funds Held - Directly Managed | U.S. government and agency
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	319,554
Fair Value	325,731
Amount at which shown in the balance sheet	325,731
Funds Held - Directly Managed | U.K. government
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	140,194
Fair Value	146,423
Amount at which shown in the balance sheet	146,423
Funds Held - Directly Managed | Other government
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	600,001
Fair Value	617,710
Amount at which shown in the balance sheet	617,710
Funds Held - Directly Managed | Corporate
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	4,398,126
Fair Value	4,615,896
Amount at which shown in the balance sheet	4,615,896
Funds Held - Directly Managed | Municipal
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	141,905
Fair Value	152,010
Amount at which shown in the balance sheet	152,010
Funds Held - Directly Managed | Residential mortgage-backed
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	339,228
Fair Value	344,617
Amount at which shown in the balance sheet	344,617
Funds Held - Directly Managed | Commercial mortgage-backed
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	783,675
Fair Value	801,472
Amount at which shown in the balance sheet	801,472
Funds Held - Directly Managed | Asset-backed
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	562,020
Fair Value	558,217
Amount at which shown in the balance sheet	558,217
Available-for-sale securities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	2,036,469
Fair Value	2,035,744
Amount at which shown in the balance sheet	2,035,744
Available-for-sale securities | U.S. government and agency
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	410,842
Fair Value	410,312
Amount at which shown in the balance sheet	410,312
Available-for-sale securities | U.K. government
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	15,067
Fair Value	15,349
Amount at which shown in the balance sheet	15,349
Available-for-sale securities | Other government
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	84,116
Fair Value	85,147
Amount at which shown in the balance sheet	85,147
Available-for-sale securities | Corporate
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	1,081,713
Fair Value	1,081,171
Amount at which shown in the balance sheet	1,081,171
Available-for-sale securities | Municipal
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	15,963
Fair Value	15,872
Amount at which shown in the balance sheet	15,872
Available-for-sale securities | Residential mortgage-backed
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	127,704
Fair Value	127,219
Amount at which shown in the balance sheet	127,219
Available-for-sale securities | Commercial mortgage-backed
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	98,928
Fair Value	98,557
Amount at which shown in the balance sheet	98,557
Available-for-sale securities | Asset-backed
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	202,136
Fair Value	202,117
Amount at which shown in the balance sheet	202,117
Mitchell International | Affiliated entity
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair value of other investments in funds or companies owned by or affiliated with related parties	$ 25,000	$ 25,000

Schedule II - Condensed Balance

Schedule II - Condensed Balance Sheets (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Cash and cash equivalents	$ 703,085	$ 602,096	$ 955,150
Other assets	744,608	707,469
TOTAL ASSETS	19,363,315	16,556,270
LIABILITIES
Debt obligations (Note 15)	1,191,207	861,539
Other liabilities	464,014	468,129
TOTAL LIABILITIES	14,068,173	12,183,738
SHAREHOLDERS’ EQUITY (Note 17)
Treasury shares, at cost (Series C Preferred Shares 2019 and 2018: 388,571)	(421,559)	(421,559)
Additional paid-in capital	1,836,778	1,804,664
Accumulated other comprehensive income	7,171	10,440
Retained earnings	2,887,892	1,976,539
Total Enstar Group Limited Shareholders’ Equity	4,842,183	3,901,933
TOTAL LIABILITIES, REDEEMABLE NONCONTROLLING INTEREST AND SHAREHOLDERS’ EQUITY	$ 19,363,315	$ 16,556,270
Parenthetical Disclosures [Abstract]
Common shares, par value (dollars per share)	$ 1	$ 1
Ordinary shares, shares issued (shares)	21,511,505	21,459,997
Ordinary shares, outstanding (shares)	21,511,505	21,459,997
Voting ordinary shares
SHAREHOLDERS’ EQUITY (Note 17)
Ordinary shares	$ 18,002	$ 17,950
Parenthetical Disclosures [Abstract]
Common shares, par value (dollars per share)	$ 1	$ 1
Ordinary shares, shares issued (shares)	18,001,823	17,950,315
Ordinary shares, outstanding (shares)	18,001,823	17,950,315
Series C non-voting convertible ordinary shares
SHAREHOLDERS’ EQUITY (Note 17)
Ordinary shares	$ 2,600	$ 2,600
Parenthetical Disclosures [Abstract]
Ordinary shares, shares issued (shares)	2,599,672	2,599,672
Ordinary shares, outstanding (shares)	2,599,672	2,599,672
Series E non-voting convertible ordinary shares
SHAREHOLDERS’ EQUITY (Note 17)
Ordinary shares	$ 910	$ 910
Parenthetical Disclosures [Abstract]
Ordinary shares, shares issued (shares)	910,010	910,010
Ordinary shares, outstanding (shares)	910,010	910,010
Series C Preferred Shares
SHAREHOLDERS’ EQUITY (Note 17)
Preferred shares	$ 389	$ 389
Parenthetical Disclosures [Abstract]
Preferred shares, issued (shares)	388,571	388,571
Preferred shares, outstanding (shares)	388,571	388,571
Treasury shares (shares)	388,571	388,571
Series D Preferred Shares
SHAREHOLDERS’ EQUITY (Note 17)
Preferred shares	$ 400,000	$ 400,000
Parenthetical Disclosures [Abstract]
Preferred shares, issued (shares)	16,000	16,000
Preferred shares, outstanding (shares)	16,000	16,000
Series E Preferred Shares
SHAREHOLDERS’ EQUITY (Note 17)
Preferred shares	$ 110,000	$ 110,000
Parenthetical Disclosures [Abstract]
Preferred shares, issued (shares)	4,400	4,400
Preferred shares, outstanding (shares)	4,400	4,400
Enstar Group Limited
ASSETS
Cash and cash equivalents	$ 4,568	$ 15,213
Balances due from subsidiaries	134,897	25,091
Investments in subsidiaries	6,050,197	4,843,913
Other assets	6,391	8,596
TOTAL ASSETS	6,196,053	4,892,813
LIABILITIES
Debt obligations (Note 15)	1,191,207	861,539
Balances due to subsidiaries	135,532	120,397
Other liabilities	27,131	8,944
TOTAL LIABILITIES	1,353,870	990,880
SHAREHOLDERS’ EQUITY (Note 17)
Treasury shares, at cost (Series C Preferred Shares 2019 and 2018: 388,571)	(421,559)	(421,559)
Additional paid-in capital	1,836,778	1,804,664
Accumulated other comprehensive income	7,171	10,440
Retained earnings	2,887,892	1,976,539
Total Enstar Group Limited Shareholders’ Equity	4,842,183	3,901,933
TOTAL LIABILITIES, REDEEMABLE NONCONTROLLING INTEREST AND SHAREHOLDERS’ EQUITY	$ 6,196,053	$ 4,892,813
Parenthetical Disclosures [Abstract]
Common shares, par value (dollars per share)	$ 1	$ 1
Ordinary shares, shares issued (shares)	21,511,505	21,459,997
Ordinary shares, outstanding (shares)	21,511,505	21,459,997
Enstar Group Limited | Voting ordinary shares
SHAREHOLDERS’ EQUITY (Note 17)
Ordinary shares	$ 18,002	$ 17,950
Parenthetical Disclosures [Abstract]
Ordinary shares, shares issued (shares)	18,001,823	17,950,315
Ordinary shares, outstanding (shares)	18,001,823	17,950,315
Enstar Group Limited | Series C non-voting convertible ordinary shares
SHAREHOLDERS’ EQUITY (Note 17)
Ordinary shares	$ 2,600	$ 2,600
Parenthetical Disclosures [Abstract]
Ordinary shares, shares issued (shares)	2,599,672	2,599,672
Ordinary shares, outstanding (shares)	2,599,672	2,599,672
Enstar Group Limited | Series E non-voting convertible ordinary shares
SHAREHOLDERS’ EQUITY (Note 17)
Ordinary shares	$ 910	$ 910
Parenthetical Disclosures [Abstract]
Ordinary shares, shares issued (shares)	910,010	910,010
Ordinary shares, outstanding (shares)	910,010	910,010
Enstar Group Limited | Series C Preferred Shares
SHAREHOLDERS’ EQUITY (Note 17)
Preferred shares	$ 389	$ 389
Parenthetical Disclosures [Abstract]
Preferred shares, issued (shares)	388,571	388,571
Preferred shares, outstanding (shares)	388,571	388,571
Treasury shares (shares)	388,571	388,571
Enstar Group Limited | Series D Preferred Shares
SHAREHOLDERS’ EQUITY (Note 17)
Preferred shares	$ 400,000	$ 400,000
Parenthetical Disclosures [Abstract]
Preferred shares, issued (shares)	16,000	16,000
Preferred shares, outstanding (shares)	16,000	16,000
Enstar Group Limited | Series E Preferred Shares
SHAREHOLDERS’ EQUITY (Note 17)
Preferred shares	$ 110,000	$ 110,000
Parenthetical Disclosures [Abstract]
Preferred shares, issued (shares)	4,400	4,400
Preferred shares, outstanding (shares)	4,400	4,400

Schedule II - Condensed Stateme

Schedule II - Condensed Statements of Earnings (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
INCOME
Net investment income	$ 79,376	$ 85,472	$ 77,732	$ 78,696	$ 68,453	$ 69,430	$ 66,469	$ 66,319	$ 321,276	$ 270,671	$ 208,789
Other income	19,502	826	11,030	5,812	34,267	8,226	(9,351)	1,943	37,170	35,085	22,605
Total income	533,235	511,395	641,214	887,267	187,909	291,980	239,864	103,782	2,573,111	823,535	1,100,952
EXPENSES
General and administrative expenses	129,569	113,924	117,519	112,074	106,950	102,553	102,612	95,260	473,086	407,375	435,985
Interest expense	13,519	14,950	13,036	11,036	4,644	4,640	8,922	8,011	52,541	26,217	28,102
Net foreign exchange losses (gains)	12,189	(13,631)	(2,587)	(3,850)	1,279	1,040	(5,519)	5,868	(7,879)	2,668	17,537
Total expenses	369,520	387,942	413,355	525,548	356,463	316,872	252,008	158,735	1,696,365	1,084,078	792,445
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED	202,764	126,668	240,767	367,890	(106,423)	(10,832)	8,244	(41,210)	938,089	(150,221)	311,458
Dividends on preferred shares	(8,925)	(8,925)	(8,925)	(9,139)	(7,000)	(5,133)	0	0	(35,914)	(12,133)	0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS	$ 193,839	$ 117,743	$ 231,842	$ 358,751	$ (113,423)	$ (15,965)	$ 8,244	$ (41,210)	902,175	(162,354)	311,458
Enstar Group Limited
INCOME
Net investment income									3,649	142	80
Other income									0	0	1,050
Dividend income from subsidiaries									0	0	249,055
Total income									3,649	142	250,185
EXPENSES
General and administrative expenses									44,964	68,977	87,596
Interest expense									51,508	27,353	23,138
Net foreign exchange losses (gains)									(21,516)	7,655	6,135
Total expenses									74,956	103,985	116,869
EARNINGS (LOSSES) BEFORE EQUITY IN UNDISTRIBUTED EARNINGS OF SUBSIDIARIES									(71,307)	(103,843)	133,316
EQUITY IN UNDISTRIBUTED EARNINGS (LOSSES) OF SUBSIDIARIES - CONTINUING OPERATIONS									1,009,396	(46,378)	167,149
EQUITY IN UNDISTRIBUTED EARNINGS (LOSSES) OF SUBSIDIARIES - DISCONTINUING OPERATIONS									0	0	10,993
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED									938,089	(150,221)	311,458
Dividends on preferred shares									(35,914)	(12,133)	0
NET EARNINGS (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED ORDINARY SHAREHOLDERS									$ 902,175	$ (162,354)	$ 311,458

Schedule II - Comprehensive Inc

Schedule II - Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Statement of Income Captions [Line Items]
NET EARNINGS	$ 202,764	$ 126,668	$ 240,767	$ 367,890	$ (106,423)	$ (10,832)	$ 8,244	$ (41,210)	$ 938,089	$ (150,221)	$ 311,458
COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED									934,820	(150,248)	345,474
Enstar Group Limited
Condensed Statement of Income Captions [Line Items]
NET EARNINGS									938,089	(150,221)	311,458
OTHER COMPREHENSIVE INCOME (LOSS) RELATING TO SUBSIDIARIES, NET OF TAX									(3,269)	(27)	34,016
COMPREHENSIVE INCOME (LOSS) ATTRIBUTABLE TO ENSTAR GROUP LIMITED									$ 934,820	$ (150,248)	$ 345,474

Schedule II - Condensed State_2

Schedule II - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
OPERATING ACTIVITIES:
Net cash flows provided by (used in) operating activities	$ 1,763,516	$ (160,072)	$ (343,107)
INVESTING ACTIVITIES:
Net cash flows provided by (used in) investing activities	(1,983,537)	(825,754)	293,262
FINANCING ACTIVITIES:
Net proceeds from the issuance of preferred shares	0	495,357	0
Dividends on preferred shares	(35,914)	(12,133)	0
Repayment of loans	(742,574)	(914,319)	(912,140)
Receipt of loans	1,070,502	1,132,507	874,100
Net cash flows provided by (used in) financing activities	293,538	752,986	(65,476)
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	73,193	(230,252)	(105,809)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING OF YEAR	982,584	1,212,836	1,318,645
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, END OF YEAR	1,055,777	982,584	1,212,836
Enstar Group Limited
OPERATING ACTIVITIES:
Net cash flows provided by (used in) operating activities	(128,462)	(128,382)	97,898
INVESTING ACTIVITIES:
Dividends and return of capital from subsidiaries	65,500	101,000	217,450
Contributions to subsidiaries	(240,382)	(660,339)	(465,650)
Net cash flows provided by (used in) investing activities	(174,882)	(559,339)	(248,200)
FINANCING ACTIVITIES:
Net proceeds from the issuance of preferred shares	0	495,357	0
Dividends on preferred shares	(35,914)	(12,133)	0
Repayment of loans	(219,000)	(898,633)	(696,640)
Receipt of loans	547,613	1,115,885	844,516
Net cash flows provided by (used in) financing activities	292,699	700,476	147,876
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(10,645)	12,755	(2,426)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING OF YEAR	15,213	2,458	4,884
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, END OF YEAR	$ 4,568	$ 15,213	$ 2,458

Schedule II - Narrative (Detail

Schedule II - Narrative (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Dividends and return of capital from subsidiaries, non-cash									$ 0	$ 0	$ 31,600,000
Contributions to subsidiaries, non-cash									0	414,800,000	148,100,000
Retained earnings	$ 2,887,892,000				$ 1,976,539,000				2,887,892,000	1,976,539,000
Net earnings attributable to Enstar Group Limited	193,839,000	$ 117,743,000	$ 231,842,000	$ 358,751,000	(113,423,000)	$ (15,965,000)	$ 8,244,000	$ (41,210,000)	902,175,000	(162,354,000)	311,458,000
Limited Parental Guarantee
Condensed Financial Statements, Captions [Line Items]
Total parental guarantees	1,031,500,000				614,500,000				1,031,500,000	614,500,000
Enstar Group Limited
Condensed Financial Statements, Captions [Line Items]
Interest paid									46,500,000	25,100,000	17,600,000
Retained earnings	2,887,892,000				$ 1,976,539,000				2,887,892,000	1,976,539,000
Increase in retained earnings									911,400,000
Net earnings attributable to Enstar Group Limited									902,175,000	$ (162,354,000)	$ 311,458,000
Enstar Group Limited | Limited Parental Guarantee
Condensed Financial Statements, Captions [Line Items]
Total parental guarantees	1,031,500,000								1,031,500,000
Letters of Credit | FAL Facility | Enstar Group Limited | Limited Parental Guarantee
Condensed Financial Statements, Captions [Line Items]
Total parental guarantees	$ 252,000,000								$ 252,000,000

Schedule III - Supplementary _2

Schedule III - Supplementary Insurance Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred Acquisition Costs	$ 153,505	$ 121,101	$ 64,984
Reserves for Losses and Loss Adjustment Expenses	10,429,238	9,409,504	7,398,088
Unearned Premiums	746,775	842,618	583,197
Policy Benefits for Life and Annuity Contracts	0	105,080	117,207
Net Premiums Earned	1,154,861	895,575	613,121
Net Investment Income	321,276	270,671	208,789
Losses and Loss Expenses and Policy Benefits	872,666	455,028	197,566
Amortization of Deferred Acquisition Costs	305,951	192,790	96,906
Other Operating Expenses	473,086	407,375	435,985
Net Premiums Written	900,959	981,900	610,390
Operating Segments | Non-life Run-off
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred Acquisition Costs	41,753	4,378	655
Reserves for Losses and Loss Adjustment Expenses	8,295,361	7,540,662	5,949,472
Unearned Premiums	129,715	136,023	14,275
Policy Benefits for Life and Annuity Contracts	0	0	0
Net Premiums Earned	168,496	9,427	14,162
Net Investment Income	275,236	226,287	166,678
Losses and Loss Expenses and Policy Benefits	51,625	(306,067)	(190,674)
Amortization of Deferred Acquisition Costs	73,642	4,006	328
Other Operating Expenses	270,445	197,824	233,827
Net Premiums Written	(25,338)	(9,217)	6,482
Operating Segments | Atrium
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred Acquisition Costs	22,184	20,355	18,385
Reserves for Losses and Loss Adjustment Expenses	231,672	241,284	240,873
Unearned Premiums	80,863	70,429	64,877
Policy Benefits for Life and Annuity Contracts	0	0	0
Net Premiums Earned	164,059	146,315	134,747
Net Investment Income	7,049	5,686	4,218
Losses and Loss Expenses and Policy Benefits	77,276	69,810	69,419
Amortization of Deferred Acquisition Costs	56,956	50,646	47,688
Other Operating Expenses	28,277	24,698	29,586
Net Premiums Written	172,356	153,488	134,214
Operating Segments | StarStone
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred Acquisition Costs	89,180	96,004	45,944
Reserves for Losses and Loss Adjustment Expenses	1,879,128	1,608,697	1,207,743
Unearned Premiums	518,199	619,164	504,045
Policy Benefits for Life and Annuity Contracts	0	0	0
Net Premiums Earned	801,926	714,959	459,403
Net Investment Income	47,401	35,973	27,706
Losses and Loss Expenses and Policy Benefits	727,636	673,383	314,806
Amortization of Deferred Acquisition Costs	174,711	135,452	48,012
Other Operating Expenses	128,419	156,726	135,558
Net Premiums Written	735,429	805,562	464,901
Other
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred Acquisition Costs	388	364	0
Reserves for Losses and Loss Adjustment Expenses	23,077	18,861	0
Unearned Premiums	17,998	17,002	0
Policy Benefits for Life and Annuity Contracts	0	105,080	117,207
Net Premiums Earned	20,380	24,874	4,809
Net Investment Income	(8,410)	2,725	10,187
Losses and Loss Expenses and Policy Benefits	16,129	17,902	4,015
Amortization of Deferred Acquisition Costs	642	2,686	878
Other Operating Expenses	45,945	28,127	37,014
Net Premiums Written	$ 18,512	$ 32,067	$ 4,793

Schedule IV - Reinsurance (Deta

Schedule IV - Reinsurance (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Life insurance in force, gross	$ 725,293				$ 855,366				$ 725,293	$ 855,366	$ 979,291
Life insurance in force, ceded	(65,795)				(84,603)				(65,795)	(84,603)	(100,189)
Life insurance in force, assumed	0				0				0	0	0
Life insurance in force, net	$ 659,498				$ 770,763				$ 659,498	$ 770,763	$ 879,102
Life insurance in force, percentage of amount assumed to net	0.00%				0.00%				0.00%	0.00%	0.00%
Premiums earned, gross									$ 1,148,251	$ 989,529	$ 905,126
Ceded, premiums earned									(267,197)	(330,136)	(434,166)
Premiums earned, assumed									273,807	236,182	142,161
Net, premiums earned	$ 272,686	$ 270,325	$ 276,563	$ 335,287	$ 231,947	$ 264,597	$ 228,812	$ 170,219	1,154,861	895,575	613,121
Property and casualty
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Premiums earned, gross									1,146,956	985,637	899,226
Ceded, premiums earned									(267,174)	(330,110)	(433,075)
Premiums earned, assumed									273,807	236,182	142,161
Net, premiums earned									$ 1,153,589	$ 891,709	$ 608,312
Premiums earned, percentage of amount assumed to net									23.70%	26.50%	23.40%
Life and annuities
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Premiums earned, gross									$ 1,295	$ 3,892	$ 5,900
Ceded, premiums earned									(23)	(26)	(1,091)
Premiums earned, assumed									0	0	0
Net, premiums earned									$ 1,272	$ 3,866	$ 4,809
Premiums earned, percentage of amount assumed to net									0.00%	0.00%	0.00%

Schedule V - Valuation and Qu_2

Schedule V - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reinsurance balances recoverable, provisions for bad debt
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 147,639	$ 156,732	$ 165,213	$ 174,516
Charged to costs and expenses	0	0	(1,536)
Charged to other accounts	111	(1,837)	(4,191)
Deductions	(9,204)	(6,644)	(3,576)
Balance at End of Year	147,639	156,732	165,213
Valuation allowance for deferred tax assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	117,390	212,113	188,300	$ 290,861
Charged to costs and expenses	2,792	(2,492)	(16,694)
Charged to other accounts	0	18,000	0
Deductions	(97,515)	8,305	(85,867)
Balance at End of Year	$ 117,390	$ 212,113	$ 188,300

Schedule VI - Supplementary I_2

Schedule VI - Supplementary Information Concerning Property/Casualty Insurance Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Abstract]
Deferred Acquisition Costs	$ 153,505	$ 121,101	$ 64,984
Reserves for Unpaid Losses and Loss Adjustment Expenses	10,429,238	9,409,504	7,398,088
Unearned Premiums	746,775	842,618	583,197
Net Premiums Earned	1,153,589	891,708	608,312
Net Investment Income	320,780	269,093	198,602
Net Losses and Loss Expenses Incurred - Current Year	823,658	689,782	437,853
Net Loses and Loss Expenses Incurred - Prior Year	48,917	(235,757)	(244,302)
Net Paid Losses and Loss Expenses	(1,869,268)	(1,384,545)	(945,194)
Amortization of Deferred Acquisition Costs	305,774	192,790	96,028
Net Premiums Written	$ 899,687	$ 978,037	$ 605,597