AXIS Capital Holdings Limited (AXS) 10-Q 3 May 19 2019 Q1 Quarterly report Financial data

DOCUMENT AND ENTITY INFORMATION

DOCUMENT AND ENTITY INFORMATION - shares	3 Months Ended
	Mar. 31, 2019	Apr. 26, 2019
DOCUMENT AND ENTITY INFORMATION [ABSTRACT]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Entity Registrant Name	AXIS CAPITAL HOLDINGS LTD
Entity Central Index Key	0001214816
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		83,935,148

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Investments:
Fixed maturities, available for sale, at fair value (Amortized cost 2019: $11,834,207; 2018: $11,616,312)	$ 11,874,518	$ 11,435,347
Equity securities, at fair value (Cost 2019: $376,493; 2018: $365,905)	418,863	381,633
Mortgage loans, held for investment, at fair value	313,421	298,650
Other investments, at fair value	795,331	787,787
Equity method investments	110,322	108,103
Short-term investments, at fair value	41,853	144,040
Total investments	13,554,308	13,155,560
Cash and cash equivalents	1,151,182	1,232,814
Restricted cash and cash equivalents	455,076	597,206
Accrued interest receivable	78,594	80,335
Insurance and reinsurance premium balances receivable	3,667,923	3,007,296
Reinsurance recoverable on unpaid losses	3,555,341	3,501,669
Reinsurance recoverable on paid losses	321,798	280,233
Deferred acquisition costs	703,028	566,622
Prepaid reinsurance premiums	1,271,303	1,013,573
Receivable for investments sold	10,888	32,627
Goodwill	102,003	102,003
Intangible assets	238,763	241,568
Value of business acquired	22,610	35,714
Operating lease right-of-use assets	143,887	0
Other assets	280,878	285,346
Total assets	25,557,582	24,132,566
Liabilities
Reserve for losses and loss expenses	12,275,771	12,280,769
Unearned premiums	4,535,163	3,635,758
Insurance and reinsurance balances payable	1,440,942	1,338,991
Senior notes	1,342,345	1,341,961
Payable for investments purchased	159,544	111,838
Operating lease liabilities	144,298	0
Other liabilities	359,363	393,178
Total liabilities	20,257,426	19,102,495
Shareholders’ equity
Preferred shares	775,000	775,000
Common shares (shares issued 2019: 176,580; 2018: 176,580 shares outstanding 2019: 83,934; 2018: 83,586)	2,206	2,206
Additional paid-in capital	2,296,639	2,308,583
Accumulated other comprehensive income (loss)	29,096	(177,110)
Retained earnings	5,976,603	5,912,812
Treasury shares, at cost (2019: 92,646; 2018: 92,994 shares)	(3,779,388)	(3,791,420)
Total shareholders’ equity	5,300,156	5,030,071
Total liabilities and shareholders’ equity	$ 25,557,582	$ 24,132,566

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Fixed maturities, available for sale, amortized cost	$ 11,834,207	$ 11,616,312
Equity securities, cost	$ 376,493	$ 365,905
Common shares, shares issued (in shares)	176,580	176,580
Common shares, shares outstanding (in shares)	83,934	83,586
Treasury shares, shares (in shares)	92,646	92,994

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues
Net premiums earned	$ 1,134,212	$ 1,167,402
Net investment income	107,303	100,999
Other insurance related income	6,929	6,606
Net investment gains (losses):
Other-than-temporary impairment (OTTI) losses	(4,036)	(414)
Other realized and unrealized investment gains (losses)	16,803	(14,416)
Total net investment gains (losses)	12,767	(14,830)
Total revenues	1,261,211	1,260,177
Expenses
Net losses and loss expenses	664,028	661,345
Acquisition costs	260,418	229,260
General and administrative expenses	175,091	169,837
Foreign exchange losses	7,056	37,860
Interest expense and financing costs	15,895	16,763
Transaction and reorganization expenses	14,820	13,054
Amortization of value of business acquired	13,104	57,110
Amortization of intangible assets	3,003	2,782
Total expenses	1,153,415	1,188,011
Income before income taxes and interest in income of equity method investments	107,796	72,166
Income tax (expense) benefit	(1,234)	1,036
Interest in income of equity method investments	2,219	0
Net income	108,781	73,202
Preferred share dividends	10,656	10,656
Net income available to common shareholders	$ 98,125	$ 62,546
Earnings per common share:
Earnings per common share (in usd per share)	$ 1.17	$ 0.75
Earnings per diluted common share (in usd per share)	$ 1.16	$ 0.75
Weighted average number of common shares outstanding - basic (in shares)	83,725	83,322
Weighted average number of common shares outstanding - diluted (in shares)	84,272	83,721

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 108,781	$ 73,202
Other comprehensive income (loss), net of tax:
Unrealized investment gains (losses) arising during the period	190,173	(112,191)
Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income	13,370	785
Unrealized investment gains (losses) arising during the period, net of reclassification adjustment	203,543	(111,406)
Foreign currency translation adjustment	2,662	1,270
Total other comprehensive income (loss), net of tax	206,205	(110,136)
Comprehensive income (loss)	$ 314,986	$ (36,934)

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Preferred shares	Common shares (par value)	Additional paid-in capital	Accumulated other comprehensive income (loss)	Unrealized gains (losses) on available for sale investments, net of tax:	Cumulative foreign currency translation adjustments, net of tax:	Retained earnings	Treasury shares, at cost
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption of ASU | Accounting Standards Update 2018-02						$ 2,142		$ (2,142)
Cumulative effect of adoption of ASU | Accounting Standards Update 2016-01						(69,604)		69,604
Balance at beginning of period at Dec. 31, 2017		$ 775,000	$ 2,206	$ 2,299,166	$ 92,382	89,962	$ 2,420	5,979,666	$ (3,807,156)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchased									(7,163)
Shares reissued				(19,272)					20,933
Share-based compensation expense				9,603
Unrealized gains (losses) arising during the period, net of reclassification adjustment	$ (111,406)					(111,406)
Foreign currency translation adjustment	1,270						1,270
Net income	73,202							73,202
Preferred share dividends								(10,656)
Common share dividends								(33,380)
Balance at beginning and end of period at Mar. 31, 2018	5,264,395	775,000	2,206	2,289,497	(85,216)	(88,906)	3,690	6,076,294	(3,793,386)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption of ASU | Accounting Standards Update 2018-02						0		0
Cumulative effect of adoption of ASU | Accounting Standards Update 2016-01						0		0
Balance at beginning of period at Dec. 31, 2018	5,030,071	775,000	2,206	2,308,583	(177,110)	(168,365)	(8,745)	5,912,812	(3,791,420)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchased									(9,003)
Shares reissued				(19,302)					21,035
Share-based compensation expense				7,358
Unrealized gains (losses) arising during the period, net of reclassification adjustment	203,543					203,543
Foreign currency translation adjustment	2,662						2,663
Net income	108,781							108,781
Preferred share dividends								(10,656)
Common share dividends								(34,334)
Balance at beginning and end of period at Mar. 31, 2019	$ 5,300,156	$ 775,000	$ 2,206	$ 2,296,639	$ 29,096	$ 35,178	$ (6,082)	$ 5,976,603	$ (3,779,388)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net income	$ 108,781	$ 73,202
Adjustments to reconcile net income to net cash used in operating activities:
Net investment (gains) losses	(12,767)	8,909
Net realized and unrealized gains on other investments	(6,528)	(12,950)
Amortization of fixed maturities	5,832	9,895
Interest in income of equity method investments	(2,219)	0
Amortization of value of business acquired	13,104	57,110
Other amortization and depreciation	23,742	11,287
Share-based compensation expense, net of cash payments	(3,679)	(1,481)
Changes in:
Accrued interest receivable	1,544	3,350
Reinsurance recoverable balances on unpaid and paid losses	(98,425)	(113,656)
Deferred acquisition costs	(136,906)	(253,369)
Prepaid reinsurance premiums	(260,567)	(218,772)
Reserve for losses and loss expenses	4,829	184,511
Unearned premiums	903,253	1,056,045
Insurance and reinsurance balances, net	(559,150)	(854,993)
Other items	(38,536)	(36,973)
Net cash used in operating activities	(57,692)	(87,885)
Cash flows from investing activities:
Fixed maturities	(2,425,086)	(2,474,418)
Equity securities	(23,503)	(42,522)
Mortgage loans	(14,965)	(59,838)
Other investments	(70,039)	(31,755)
Short-term investments	(85,045)	(57,688)
Proceeds from the sale of:
Fixed maturities	1,978,928	2,442,673
Equity securities	14,875	194,970
Other investments	67,865	44,493
Short-term investments	185,445	46,719
Proceeds from redemption of fixed maturities	278,150	319,526
Proceeds from redemption of short-term investments	2,413	16,022
Proceeds from the repayment of mortgage loans	243	20,237
Purchase of other assets	(12,051)	0
Net cash provided by (used in) investing activities	(102,770)	418,419
Cash flows from financing activities:
Taxes paid on withholding shares	(9,003)	(7,163)
Dividends paid - common shares	(36,260)	(35,273)
Dividends paid - preferred shares	(10,656)	(10,656)
Net cash used in financing activities	(55,919)	(53,092)
Effect of exchange rate changes on foreign currency cash, cash equivalents, and restricted cash	(7,381)	3,354
Increase (decrease) in cash, cash equivalents, and restricted cash	(223,762)	280,796
Cash, cash equivalents, and restricted cash - beginning of period	1,830,020	1,363,786
Cash, cash equivalents, and restricted cash - end of period	1,606,258	1,644,582
Supplemental disclosures of cash flow information:
Income taxes paid	1,321	4,412
Interest paid	$ 0	$ 10,306

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (Parenthetical) - Syndicate 2007 $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Consideration for RITC	$ 819
Transfer of securities	$ 600

BASIS OF PRESENTATION AND SIGNI

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	Basis of Presentation These unaudited Consolidated Financial Statements (the "financial statements") have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") for interim financial information and with the U.S. Securities and Exchange Commission's ("SEC") instructions to Form 10-Q and Article 10 of Regulation S-X and include AXIS Capital Holdings Limited ("AXIS Capital") and its subsidiaries (the "Company"). Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. This Quarterly Report on Form 10-Q should be read in conjunction with the financial statements and related notes included in AXIS Capital's Annual Report on Form 10-K for the year ended December 31, 2018 , as filed with the SEC. In the opinion of management, these financial statements reflect all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the Company's financial position and results of operations for the periods presented. The results of operations for any interim period are not necessarily indicative of the results for a full year. All inter-company accounts and transactions have been eliminated. To facilitate comparison of information across periods, certain reclassifications have been made to prior year amounts to conform to the current year's presentation. These reclassifications did not impact results of operations, financial condition or liquidity. Tabular dollar and share amounts are in thousands, except per share amounts. All amounts are reported in U.S. dollars. Significant Accounting Policies There was no notable change to the Company's significant accounting policies subsequent to its Annual Report on Form 10-K for the year ended December 31, 2018 . New Accounting Standards Adopted in 2019 Leases Effective January 1, 2019, the Company adopted ASU 2016-02, "Leases (Topic 842)", which provides a new comprehensive model for lease accounting. Topic 842 requires a lessee to recognize a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. The adoption of this standard resulted in the recognition of lease liabilities and right-of-use assets of $144 million in the Company's consolidated balance sheet at March 31, 2019 , related to office property and equipment leases. In addition, the Company adopted ASU 2018-11, "Leases (Topic 842) - Targeted Improvements ", which provides an additional (and optional) transition method to adopt the new lease guidance. Under the alternative transition method, the Company's reporting for the comparative periods presented in its financial statements will be in accordance with the pre-effective date lease accounting requirements (Topic 840). The Company also elected the package of practical expedients permitted under the transition guidance of Topic 842, which were elected as a package and applied consistently to all leases. At the adoption date, the package of practical expedients permitted the Company not to reassess the following: 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. In addition to electing the package of practical expedients, the Company made an accounting policy election to account for non-lease components separately from lease components. As a result, the non-lease components associated with the Company's leases are not included in the lease liabilities and right-of-use assets in the Company's consolidated balance at March 31, 2019 . Further, the Company made an accounting policy election not to record office property and equipment leases with an initial term of 12 months or less (short-term) in the Company's consolidated balance sheets. For the three months ended March 31, 2019 , the Company recognized expense for short-term leases of $0.6 million in the Company's consolidated statements of operations. The adoption of this guidance did not impact the Company's retained earnings, results of operations, or liquidity. Premium Amortization on Purchased Callable Debt Securities Effective January 1, 2019, the Company adopted ASU 2017-08 "Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) - Premium Amortization on Purchased Callable Debt Securities" which shortens the amortization period for certain purchased callable debt securities held at a premium. The adoption of this guidance did not impact the Company's results of operations, financial condition or liquidity. Changes to Disclosures on Fair Value Measurement Effective January 1, 2019, the Company adopted ASU 2018-13 "Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement " which aims to improve the effectiveness of fair value measurement disclosures. The adoption of this guidance did not impact the Company's results of operations, financial condition or liquidity. Recently Issued Accounting Standards Not Yet Adopted Measurement of Credit Losses on Financial Instrument In June 2016, the FASB issued ASU 2016-13, "Financial Instruments - Credit Losses (Topic 326) - Measurement of Credit Losses on Financial Instruments " which replaces the "incurred loss" impairment methodology with an approach based on "expected losses" to estimate credit losses on certain types of financial instruments and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The guidance requires financial assets to be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the cost of the financial asset to present the net carrying value at the amount expected to be collected on the financial asset. Credit losses relating to available-for-sale debt securities will be recorded through an allowance for credit losses. The guidance also provides for a simplified accounting model for purchased financial assets with credit deterioration since their origination. This guidance is effective for interim and annual periods beginning after December 15, 2019. Early adoption is permitted for interim and annual periods beginning after December 15, 2018. The Company is currently evaluating the impact of this guidance on its results of operations, financial condition and liquidity.

SEGMENT INFORMATION

SEGMENT INFORMATION	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
SEGMENT INFORMATION	AXIS Capital's underwriting operations are organized around its global underwriting platforms, AXIS Insurance and AXIS Re. The Company has determined that it has two reportable segments, insurance and reinsurance. The Company does not allocate its assets by segment, with the exception of goodwill and intangible assets, as it evaluates the underwriting results of each segment separately from the results of its investment portfolio. Insurance The Company's insurance segment offers specialty insurance products to a variety of niche markets on a worldwide basis. The product lines in this segment are property, marine, terrorism, aviation, credit and political risk, professional lines, liability, accident and health, and discontinued lines - Novae. Reinsurance The Company's reinsurance segment provides treaty reinsurance to insurance companies on a worldwide basis. The product lines in this segment are catastrophe, property, professional lines, credit and surety, motor, liability, agriculture, engineering, marine and other, accident and health, and discontinued lines - Novae. The following tables present the underwriting results of the Company's reportable segments, as well as the carrying values of allocated goodwill and intangible assets: 2019 2018 Three months ended and at March 31, Insurance Reinsurance Total Insurance Reinsurance Total Gross premiums written $ 851,096 $ 1,732,130 $ 2,583,226 $ 880,848 $ 1,781,947 $ 2,662,795 Net premiums written 529,239 1,247,820 1,777,059 547,893 1,437,978 1,985,871 Net premiums earned 556,762 577,450 1,134,212 580,059 587,343 1,167,402 Other insurance related income 1,742 5,187 6,929 620 5,986 6,606 Net losses and loss expenses (313,776 ) (350,252 ) (664,028 ) (321,538 ) (339,807 ) (661,345 ) Acquisition costs (117,775 ) (142,643 ) (260,418 ) (87,329 ) (141,931 ) (229,260 ) General and administrative expenses (106,034 ) (32,839 ) (138,873 ) (102,370 ) (37,296 ) (139,666 ) Underwriting income $ 20,919 $ 56,903 77,822 $ 69,442 $ 74,295 143,737 Net investment income 107,303 100,999 Net investment gains (losses) 12,767 (14,830 ) Corporate expenses (36,218 ) (30,171 ) Foreign exchange losses (7,056 ) (37,860 ) Interest expense and financing costs (15,895 ) (16,763 ) Transaction and reorganization expenses (14,820 ) (13,054 ) Amortization of value of business acquired (13,104 ) (57,110 ) Amortization of intangible assets (3,003 ) (2,782 ) Income before income taxes and interest in income of equity method investments $ 107,796 $ 72,166 Net loss and loss expense ratio 56.4 % 60.7 % 58.5 % 55.4 % 57.9 % 56.7 % Acquisition cost ratio 21.2 % 24.7 % 23.0 % 15.1 % 24.2 % 19.6 % General and administrative expense ratio 19.0 % 5.6 % 15.4 % 17.6 % 6.3 % 14.5 % Combined ratio 96.6 % 91.0 % 96.9 % 88.1 % 88.4 % 90.8 % Total intangible assets $ 363,376 $ — $ 363,376 $ 506,747 $ — $ 506,747

INVESTMENTS

INVESTMENTS	3 Months Ended
	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
INVESTMENTS	a) Fixed Maturities and Equity securities Fixed maturities The amortized cost and fair values of the Company's fixed maturities classified as available for sale were as follows: Amortized cost Gross unrealized gains Gross unrealized losses Fair value Non-credit OTTI in AOCI (5) At March 31, 2019 Fixed maturities U.S. government and agency $ 1,965,801 $ 12,365 $ (4,512 ) $ 1,973,654 $ — Non-U.S. government 488,056 6,448 (6,841 ) 487,663 — Corporate debt 4,809,079 62,910 (33,724 ) 4,838,265 — Agency RMBS (1) 1,708,610 14,430 (17,078 ) 1,705,962 — CMBS (2) 1,040,474 13,491 (1,825 ) 1,052,140 — Non-Agency RMBS 47,125 1,307 (1,021 ) 47,411 (819 ) ABS (3) 1,619,648 2,710 (9,348 ) 1,613,010 — Municipals (4) 155,414 1,481 (482 ) 156,413 — Total fixed maturities $ 11,834,207 $ 115,142 $ (74,831 ) $ 11,874,518 $ (819 ) At December 31, 2018 Fixed maturities U.S. government and agency $ 1,520,142 $ 4,232 $ (8,677 ) $ 1,515,697 $ — Non-U.S. government 507,550 1,586 (16,120 ) 493,016 — Corporate debt 4,990,279 15,086 (128,444 ) 4,876,921 — Agency RMBS (1) 1,666,684 6,508 (29,884 ) 1,643,308 — CMBS (2) 1,103,507 2,818 (13,795 ) 1,092,530 — Non-Agency RMBS 40,732 1,237 (1,282 ) 40,687 (857 ) ABS (3) 1,651,350 1,493 (15,240 ) 1,637,603 — Municipals (4) 136,068 914 (1,397 ) 135,585 — Total fixed maturities $ 11,616,312 $ 33,874 $ (214,839 ) $ 11,435,347 $ (857 ) (1) Residential mortgage-backed securities ("RMBS") originated by U.S. government-sponsored agencies. (2) Commercial mortgage-backed securities ("CMBS"). (3) Asset-backed securities ("ABS") include debt tranched securities collateralized primarily by auto loans, student loans, credit card receivables, collateralized debt obligations ("CDOs") and collateralized loan obligations ("CLOs"). (4) Municipals include bonds issued by states, municipalities and political subdivisions. (5) Represents the non-credit component of the other-than-temporary impairment ("OTTI") losses, adjusted for subsequent sales, maturities and redemptions. It does not include the change in fair value subsequent to the impairment measurement date. Equity Securities The cost and fair values of the Company's equity securities were as follows: Cost Gross unrealized gains Gross unrealized losses Fair value At March 31, 2019 Equity securities Common stocks $ 693 $ 207 $ (315 ) $ 585 Exchange-traded funds 221,337 54,511 (4,240 ) 271,608 Bond mutual funds 154,463 — (7,793 ) 146,670 Total equity securities $ 376,493 $ 54,718 $ (12,348 ) $ 418,863 At December 31, 2018 Equity securities Common stocks $ 790 $ 112 $ (375 ) $ 527 Exchange-traded funds 213,420 33,498 (10,079 ) 236,839 Bond mutual funds 151,695 — (7,428 ) 144,267 Total equity securities $ 365,905 $ 33,610 $ (17,882 ) $ 381,633 In the normal course of investing activities, the Company actively manages allocations to non-controlling tranches of structured securities which are variable interests issued by Variable Interest Entities ("VIEs"). These structured securities include RMBS, CMBS and ABS. The Company also invests in limited partnerships including hedge funds, direct lending funds, private equity funds and real estate funds as well as CLO equity tranched securities, which are all variable interests issued by VIEs (refer to Note 3(c) ' Other Investments '). The Company does not have the power to direct the activities that are most significant to the economic performance of the VIEs therefore the Company is not the primary beneficiary of any of these VIEs. The maximum exposure to loss on these interests is limited to the amount of investment made by the Company. The Company has not provided financial or other support with respect to these structured securities other than the original investment. Contractual Maturities Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. The contractual maturities of fixed maturities are shown below: Amortized cost Fair value % of Total fair value At March 31, 2019 Maturity Due in one year or less $ 408,537 $ 407,667 3.4 % Due after one year through five years 4,952,184 4,978,429 41.9 % Due after five years through ten years 1,710,102 1,719,806 14.5 % Due after ten years 347,527 350,093 2.9 % 7,418,350 7,455,995 62.7 % Agency RMBS 1,708,610 1,705,962 14.4 % CMBS 1,040,474 1,052,140 8.9 % Non-Agency RMBS 47,125 47,411 0.4 % ABS 1,619,648 1,613,010 13.6 % Total $ 11,834,207 $ 11,874,518 100.0 % At December 31, 2018 Maturity Due in one year or less $ 430,390 $ 426,142 3.7 % Due after one year through five years 4,751,064 4,691,263 41.0 % Due after five years through ten years 1,762,452 1,697,737 14.8 % Due after ten years 210,133 206,077 1.8 % 7,154,039 7,021,219 61.3 % Agency RMBS 1,666,684 1,643,308 14.4 % CMBS 1,103,507 1,092,530 9.6 % Non-Agency RMBS 40,732 40,687 0.4 % ABS 1,651,350 1,637,603 14.3 % Total $ 11,616,312 $ 11,435,347 100.0 % Gross Unrealized Losses The following table summarizes fixed maturities and equity securities in an unrealized loss position and the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position: 12 months or greater Less than 12 months Total Fair value Unrealized losses Fair value Unrealized losses Fair value Unrealized losses At March 31, 2019 (1) Fixed maturities U.S. government and agency $ 371,995 $ (4,194 ) $ 220,718 $ (318 ) $ 592,713 $ (4,512 ) Non-U.S. government 95,715 (3,368 ) 136,310 (3,473 ) 232,025 (6,841 ) Corporate debt 1,134,227 (20,122 ) 727,267 (13,602 ) 1,861,494 (33,724 ) Agency RMBS 849,681 (16,949 ) 26,971 (129 ) 876,652 (17,078 ) CMBS 244,188 (1,500 ) 85,473 (325 ) 329,661 (1,825 ) Non-Agency RMBS 9,360 (905 ) 12,111 (116 ) 21,471 (1,021 ) ABS 273,759 (2,757 ) 846,715 (6,591 ) 1,120,474 (9,348 ) Municipals 42,745 (452 ) 15,779 (30 ) 58,524 (482 ) Total fixed maturities $ 3,021,670 $ (50,247 ) $ 2,071,344 $ (24,584 ) $ 5,093,014 $ (74,831 ) At December 31, 2018 Fixed maturities U.S. government and agency $ 374,030 $ (7,659 ) $ 424,439 $ (1,018 ) $ 798,469 $ (8,677 ) Non-U.S. government 44,339 (2,004 ) 303,376 (14,116 ) 347,715 (16,120 ) Corporate debt 1,439,378 (58,915 ) 2,547,135 (69,529 ) 3,986,513 (128,444 ) Agency RMBS 940,645 (29,255 ) 117,181 (629 ) 1,057,826 (29,884 ) CMBS 455,582 (11,430 ) 353,802 (2,365 ) 809,384 (13,795 ) Non-Agency RMBS 9,494 (1,170 ) 11,432 (112 ) 20,926 (1,282 ) ABS 237,237 (2,755 ) 1,150,692 (12,485 ) 1,387,929 (15,240 ) Municipals 68,814 (1,373 ) 9,894 (24 ) 78,708 (1,397 ) Total fixed maturities $ 3,569,519 $ (114,561 ) $ 4,917,951 $ (100,278 ) $ 8,487,470 $ (214,839 ) Fixed Maturities At March 31, 2019 , 2,521 fixed maturities ( 2018 : 3,599 ) were in an unrealized loss position of $75 million ( 2018 : $215 million ), of which $15 million ( 2018 : $49 million ) was related to securities below investment grade or not rated. At March 31, 2019 , 1,553 fixed maturities ( 2018 : 1,656 ) had been in a continuous unrealized loss position for twelve months or greater and had a fair value of $3,022 million ( 2018 : $3,570 million ). Following a credit impairment review, it was concluded that these securities as well as the remaining securities in an unrealized loss position were temporarily impaired at March 31, 2019 , and were expected to recover in value as the securities approach maturity. At March 31, 2019 , the Company did not intend to sell the securities in an unrealized loss position and it is more likely than not that the Company will not be required to sell these securities before the anticipated recovery of their amortized costs. b) Mortgage Loans The following table provides details of the Company's mortgage loans held-for-investment: March 31, 2019 December 31, 2018 Carrying value % of Total Carrying value % of Total Mortgage Loans held-for-investment: Commercial $ 313,421 100 % $ 298,650 100 % Total Mortgage Loans held-for-investment $ 313,421 100 % $ 298,650 100 % The primary credit quality indicator for commercial mortgage loans is the debt service coverage ratio which compares a property’s net operating income to amounts needed to service the principal and interest due under the loan, (generally, the lower the debt service coverage ratio, the higher the risk of experiencing a credit loss) and the loan-to-value ratio which compares the unpaid principal balance of the loan to the estimated fair value of the underlying collateral (generally, the higher the loan-to-value ratio, the higher the risk of experiencing a credit loss). The debt service coverage ratio and loan-to-value ratio, as well as the values utilized in calculating these ratios, are updated annually, on a rolling basis. The Company has a high quality mortgage loan portfolio with weighted average debt service coverage ratios in excess of 2.2 x and weighted average loan-to-value ratios of less than 60% . At March 31, 2019 , there are no credit losses or past due amounts associated with the commercial mortgage loans held by the Company. c) Other Investments The following tables provide a summary of the Company's other investments, together with additional information relating to the liquidity of each category: Fair value Redemption frequency (if currently eligible) Redemption notice period At March 31, 2019 Long/short equity funds $ 29,324 4 % Annually 60 days Multi-strategy funds 149,509 19 % Quarterly, Semi-annually 60-90 days Event-driven funds 5,914 1 % n/a n/a Direct lending funds 272,752 34 % n/a n/a Private equity funds 61,526 8 % n/a n/a Real estate funds 111,169 14 % n/a n/a CLO-Equities 18,022 1 % n/a n/a Other privately held investments 47,685 6 % n/a n/a Overseas deposits 99,430 13 % n/a n/a Total other investments $ 795,331 100 % At December 31, 2018 Long/short equity funds $ 26,779 3 % Annually 60 days Multi-strategy funds 153,883 20 % Quarterly, Semi-annually 60-95 days Event-driven funds 13,936 2 % Annually 45 days Direct lending funds 274,478 35 % n/a n/a Private equity funds 64,566 8 % n/a n/a Real estate funds 84,202 11 % n/a n/a CLO-Equities 21,271 2 % n/a n/a Other privately held investments 44,518 6 % n/a n/a Overseas deposits 104,154 13 % n/a n/a Total other investments $ 787,787 100 % n/a - not applicable The investment strategies for the above funds are as follows: • Long/short equity funds : Seek to achieve attractive returns primarily by executing an equity trading strategy involving long and short investments in publicly-traded equity securities. • Multi-strategy funds : Seek to achieve above-market returns by pursuing multiple investment strategies to diversify risks and reduce volatility. This category includes funds of hedge funds which invest in a large pool of hedge funds across a diversified range of hedge fund strategies. • Event-driven funds : Seek to achieve attractive returns by exploiting situations where announced or anticipated events create opportunities. • Direct lending funds : Seek to achieve attractive risk-adjusted returns, including current income generation, by investing in funds which provide financing directly to borrowers. • Private equity funds : Seek to achieve attractive risk-adjusted returns by investing in private transactions over the course of several years. • Real estate funds : Seek to achieve attractive risk-adjusted returns by making and managing investments in real estate and real estate securities and businesses. Two common redemption restrictions which may impact the Company's ability to redeem hedge funds are gates and lockups. A gate is a suspension of redemptions which may be implemented by the general partner or investment manager of the fund in order to defer, in whole or in part, the redemption request in the event the aggregate amount of redemption requests exceeds a predetermined percentage of the fund's net assets which may otherwise hinder the general partner or investment manager's ability to liquidate holdings in an orderly fashion in order to generate the cash necessary to fund extraordinarily large redemption payouts. A lockup period is the initial amount of time an investor is contractually required to hold the security before having the ability to redeem. During the three months ended March 31, 2019 and 2018 , neither of these restrictions impacted the Company's redemption requests. At March 31, 2019 , $42 million ( 2018 : $27 million ), representing 23% ( 2018 : 14% ) of total hedge funds, relate to holdings where the Company is still within the lockup period. The expiration of these lockup periods range from October 2020 to March 2022. At March 31, 2019 , the Company had $200 million ( 2018 : $210 million ) of unfunded commitments as a limited partner in direct lending funds. Once the full amount of committed capital has been called by the General Partner of each of these funds, the assets will not be fully returned until the completion of the fund's investment term. These funds have investment terms ranging from five to ten years and the General Partners of certain funds have the option to extend the term by up to three years. At March 31, 2019 , the Company had $53 million ( 2018 : $84 million ) of unfunded commitments as a limited partner in multi-strategy hedge funds. Once the full amount of committed capital has been called by the General Partner of each of these funds, the assets will not be fully returned until after the completion of the funds' investment term. These funds have investment terms ranging from two years to the dissolution of the underlying fund. At March 31, 2019 , the Company had $115 million ( 2018 : $147 million ) of unfunded commitments as a limited partner in funds which invest in real estate and real estate securities and businesses. These funds include an open-ended fund and funds with investment terms ranging from seven years to the dissolution of the underlying fund. At March 31, 2019 , the Company had $16 million ( 2018 : $16 million ) of unfunded commitments as a limited partner in a private equity fund. The life of the fund is subject to the dissolution of the underlying funds. The Company expects the overall holding period to be over ten years. During 2015, the Company made a $50 million commitment as a limited partner of a bank revolver opportunity fund. The fund has an investment term of seven years and the General Partners have the option to extend the term by up to two years. At March 31, 2019 , this commitment remains unfunded. It is not anticipated that the full amount of this fund will be drawn. Syndicate 2007 holds overseas deposits which include investments in private funds where the underlying investments are primarily U.S. government, Non-U.S. government and corporate debt securities. The funds do not trade on an exchange therefore are not included within available for sale investments. d) Equity Method Investments During 2016, the Company paid $108 million including direct transaction costs to acquire 19% of the common equity of Harrington Reinsurance Holdings Limited ("Harrington"), the parent company of Harrington Re Ltd. ("Harrington Re"), an independent reinsurance company jointly sponsored by AXIS Capital and The Blackstone Group L.P. ("Blackstone"). Through long-term service agreements, AXIS Capital will serve as Harrington Re's reinsurance underwriting manager and Blackstone will serve as exclusive investment management service provider. As an investor, the Company expects to benefit from underwriting profit generated by Harrington Re and the income and capital appreciation Blackstone seeks to deliver through its investment management services. In addition, the Company has entered into an arrangement with Blackstone under which underwriting and investment related fees will be shared equally. Harrington is not a VIE that is required to be included in the Company's consolidated financial statements. The Company accounts for its ownership interest in Harrington under the equity method of accounting. The Company's proportionate share of the underlying equity in net assets resulted in a basis difference of $5 million which represents initial transactions costs. e) Net Investment Income Net investment income was derived from the following sources: Three months ended March 31, 2019 2018 Fixed maturities $ 91,382 $ 83,958 Other investments 6,895 13,704 Equity securities 2,328 1,758 Mortgage loans 3,063 3,125 Cash and cash equivalents 5,801 4,153 Short-term investments 3,894 875 Gross investment income 113,363 107,573 Investment expenses (6,060 ) (6,574 ) Net investment income $ 107,303 $ 100,999 f) Net Investment Gains (Losses) The following table provides an analysis of net investment gains (losses): Three months ended March 31, 2019 2018 Gross realized investment gains Fixed maturities and short-term investments $ 10,437 $ 31,628 Equity securities 1,445 17,557 Gross realized investment gains 11,882 49,185 Gross realized investment losses Fixed maturities and short-term investments (20,279 ) (43,535 ) Equity securities (93 ) (1,276 ) Gross realized investment losses (20,372 ) (44,811 ) Net OTTI recognized in net income (4,036 ) (414 ) Change in fair value of investment derivatives (1) (2,102 ) 2,023 Net unrealized gains (losses) on equity securities 27,395 (20,813 ) Net investment gains (losses) $ 12,767 $ (14,830 ) (1) Refer to Note 5 ' Derivative Instruments'. The following table summarizes the OTTI recognized in net income by asset class: Three months ended March 31, 2019 2018 Fixed maturities: Non-U.S. government $ 60 $ — Corporate debt 3,976 414 Total OTTI recognized in net income $ 4,036 $ 414 The following table provides a roll forward of the credit losses ("credit loss table") before income taxes, for which a component of the OTTI charge was recognized in AOCI: Three months ended March 31, 2019 2018 Balance at beginning of period $ 510 $ 1,494 Credit impairments recognized on securities not previously impaired — — Additional credit impairments recognized on securities previously impaired — — Change in timing of future cash flows on securities previously impaired — — Intent to sell of securities previously impaired — — Securities sold/redeemed/matured (38 ) (10 ) Balance at end of period $ 472 $ 1,484 g) Reverse Repurchase Agreements At March 31, 2019 , the Company held $97 million ( 2018 : $ 189 million ) of reverse repurchase agreements. These loans are fully collateralized, are generally outstanding for a short period of time and are presented on a gross basis as part of cash and cash equivalents in the Company's consolidated balance sheets. The required collateral for these loans is either cash or U.S. Treasuries at a minimum rate of 102% of the loan principal. Upon maturity, the Company receives principal and interest income. The Company monitors the estimated fair value of the securities loaned and borrowed on a daily basis with additional collateral obtained as necessary throughout the duration of the transaction.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	Fair Value Hierarchy Fair value is defined as the price to sell an asset or transfer a liability (i.e. the "exit price") in an orderly transaction between market participants. U.S. GAAP prescribes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to quoted prices in active markets and the lowest priority to unobservable data. The level in the hierarchy within which a given fair value measurement falls is determined based on the lowest level input that is significant to the measurement. 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 the Company has the ability to access. • 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 inputs that are unobservable and significant to the overall fair value measurement. The unobservable inputs reflect the Company's own judgments about assumptions that market participants might use. The availability of observable inputs can vary from financial instrument to financial instrument and is affected by a wide variety of factors including, for example, the type of financial instrument, whether the financial instrument is new and not yet established in the marketplace, and other characteristics particular to the transaction. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires significantly more judgment. Accordingly, the degree of judgment exercised by management in determining fair value is greatest for financial instruments categorized in Level 3. In periods of market dislocation, the observability of prices and inputs may be reduced for many financial instruments. This may lead the Company to change the selection of valuation technique (from market to cash flow approach) or may cause the Company to use multiple valuation techniques to estimate the fair value of a financial instrument. This circumstance could cause an instrument to be reclassified between levels within the fair value hierarchy. Valuation Techniques The valuation techniques, including significant inputs and assumptions generally used to determine the fair values of the Company's financial instruments as well as the classification of the fair values of its financial instruments in the fair value hierarchy are described in detail below. Fixed Maturities At each valuation date, the Company uses the market approach valuation technique to estimate the fair value of its fixed maturities portfolio, when possible. This market approach includes, but is not limited to, prices obtained from third party pricing services for identical or comparable securities and the use of "pricing matrix models" using observable market inputs such as yield curves, credit risks and spreads, measures of volatility, and prepayment speeds. Pricing from third party pricing services is sourced from multiple vendors, when available, and the Company maintains a vendor hierarchy by asset type based on historical pricing experience and vendor expertise. When prices are unavailable from pricing services, the Company obtains non-binding quotes from broker-dealers who are active in the corresponding markets. The valuation techniques including significant inputs and assumptions generally used to determine the fair values of the Company's fixed maturities by asset class as well as the classifications of the fair values of these securities in the fair value hierarchy are described in detail below. U.S. Government and Agency U.S. government and agency securities consist primarily of bonds 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 the Government National Mortgage Association. As the fair values of U.S. Treasury securities are based on unadjusted market prices in active markets, these securities are classified as Level 1. The fair values of U.S. government agency securities are determined using the spread above the risk-free yield curve. As the yields for the risk-free yield curve and the spreads are observable market inputs, the fair values of U.S. government agency securities are classified as Level 2. Non-U.S. Government Non-U.S. government securities include bonds issued by non-U.S. governments and their agencies along with supranational organizations (collectively also known as sovereign debt securities). The fair values of these securities are based on prices obtained from international indices or valuation models that include inputs such as interest rate yield curves, cross-currency basis index spreads, and country credit spreads for structures similar to the sovereign bond in terms of issuer, maturity and seniority. As the significant inputs used to price these securities are observable market inputs, the fair values of non-U.S. government securities are classified as Level 2. Corporate Debt Corporate debt securities consist primarily of investment-grade debt of a wide variety of corporate issuers and industries. The fair values of these securities are generally determined using the spread above the risk-free yield curve. These spreads are generally obtained from the new issue market, secondary trading and broker-dealer quotes. As the yields for the risk-free yield curve and the spreads are observable market inputs, the fair values of corporate debt securities are generally classified as Level 2. Where pricing is unavailable from pricing services, the Company obtains non-binding quotes from broker-dealers to estimate fair value. This is generally the case when there is a low volume of trading activity and current transactions are not orderly. In this event, the fair values of these securities are classified as Level 3. Agency RMBS Agency RMBS consist of bonds issued by the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation and the Government National Mortgage Association. The fair values of these securities are priced using a mortgage pool specific model which uses daily inputs from the active to be announced market and the spread associated with each mortgage pool based on vintage. As the significant inputs used to price these securities are observable market inputs, the fair values of Agency RMBS are classified as Level 2. CMBS CMBS include mostly investment-grade bonds originated by non-agencies. The fair values of these securities are determined using a pricing model which uses dealer quotes and other available trade information along with security level characteristics to determine deal specific spreads. As the significant inputs used to price these securities are observable market inputs, the fair values of CMBS securities are generally classified as Level 2. Where pricing is unavailable from pricing services, the Company obtains non-binding quotes from broker-dealers to estimate fair value. This is generally the case when there is a low volume of trading activity and current transactions are not orderly. I n this event, the fair values of these securities are classified as Level 3. Non-Agency RMBS Non-Agency RMBS include mostly investment-grade bonds originated by non-agencies. The fair values of these securities are determined using an option adjusted spread model or other relevant models, which use inputs including available trade information or broker quotes, prepayment and default projections based on historical statistics of the underlying collateral and current market data. As the significant inputs used to price these securities are observable market inputs, the fair values of Non-Agency RMBS are generally classified as Level 2. Where pricing is unavailable from pricing services, the Company obtains non-binding quotes from broker-dealers to estimate fair value. This is generally the case when there is a low volume of trading activity and current transactions are not orderly. I n this event, the fair values of these securities are classified as Level 3. ABS ABS include mostly investment-grade bonds backed by pools of loans with a variety of underlying collateral, including auto loans, student loans, credit card receivables, CDOs and CLO debt originated by a variety of financial institutions. The fair values of these securities are determined using a model which uses prepayment speeds and spreads sourced primarily from the new issue market. As the significant inputs used to price these securities are observable market inputs, the fair values of ABS are generally classified as Level 2. Where pricing is unavailable from pricing services, the Company obtains non-binding quotes from broker-dealers t o estimate fair value. This is generally the case when there is a low volume of trading activity and current transactions are not orderly. I n this event, the fair values of these securities are classified as Level 3. Municipals Municipals comprise revenue and general obligation bonds issued by U.S. domiciled state and municipal entities. The fair values of these securities are determined using spreads obtained from the new issue market, trade prices and broker-dealers quotes. As the significant inputs used to price these securities are observable market inputs, the fair values of municipals are classified as Level 2. Equity Securities Equity securities include common stocks, exchange-traded funds and bond mutual funds. As the fair values of common stocks and exchange-traded funds are based on unadjusted quoted market prices in active markets, the fair value of these securities are classified as Level 1. As bond mutual funds have daily liquidity, the fair values of these securities are classified as Level 2. Other Investments Other privately held securities include convertible preferred shares, convertible notes and notes payable. These securities are initially valued at cost which approximates fair value. In subsequent measurement periods, the fair values of these securities are determined using an income approach valuation technique, specifically an internally developed discounted cash flow model. As the significant inputs used to price these securities are unobservable, the fair values of other investments are classified as Level 3. The fair value of the indirect investment in CLO-Equities is classified as Level 3 as the fair value of this security is estimated using an income approach valuation technique, specifically an externally developed discounted cash flow model due to the lack of observable and relevant trades in secondary markets. Overseas deposits include investments in private funds held by Syndicate 2007 where the underlying investments are primarily U.S. government, Non-U.S. government and corporate debt securities. The funds do not trade on an exchange therefore are not included within available for sale investments. As the significant inputs used to price the underlying investments are observable market inputs, the fair values of overseas deposits are classified as Level 2. Short-term Investments Short-term investments primarily comprise highly liquid securities with maturities greater than three months but less than one year from the date of purchase. The fair values of these securities are classified as Level 2 because these securities are typically not actively traded due to their approaching maturity and, as such, their amortized cost approximates fair value. Derivative Instruments Derivative instruments include foreign exchange forward contracts and exchange traded interest rate swaps that are customized to the Company's economic hedging strategies and trade in the over-the-counter derivative market. The fair values of these derivatives are determined using a market approach valuation technique based on significant observable market inputs from third party pricing vendors, non-binding broker-dealer quotes and/or recent trading activity. As the significant inputs used to price these securities are observable market inputs, the fair values of these derivatives are classified as Level 2. Other underwriting-related derivatives include insurance and reinsurance contracts that are accounted for as derivatives. These derivative contracts are initially valued at cost which approximates fair value. In subsequent measurement periods, the fair values of these derivatives are determined using an income approach valuation technique, specifically internally developed discounted cash flow models. As the significant inputs used to price these derivatives are unobservable, the fair values of these contracts are classified as Level 3. Insurance-linked Securities Insurance-linked securities comprise an investment in a catastrophe bond. As pricing is unavailable from pricing services, the Company obtains non-binding quotes from broker-dealers to estimate the fair value of this security. Pricing is generally unavailable when there is a low volume of trading activity and current transactions are not orderly therefore the fair value of this security is classified as Level 3. Cash Settled Awards Cash settled awards comprise restricted stock units that form part of the Company's compensation program. Although the fair values of these awards are determined using observable quoted market prices in active markets, the restricted stock units are not actively traded. As the significant inputs used to price these securities are observable market inputs, the fair values of these liabilities are classified as Level 2. The tables below present the financial instruments measured at fair value on a recurring basis for the periods indicated: Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Fair value based on NAV practical expedient Total fair value At March 31, 2019 Assets Fixed maturities U.S. government and agency $ 1,958,315 $ 15,339 $ — $ — $ 1,973,654 Non-U.S. government — 487,663 — — 487,663 Corporate debt — 4,797,140 41,125 — 4,838,265 Agency RMBS — 1,705,962 — — 1,705,962 CMBS — 1,040,995 11,145 — 1,052,140 Non-Agency RMBS — 47,411 — — 47,411 ABS — 1,600,967 12,043 — 1,613,010 Municipals — 156,413 — — 156,413 1,958,315 9,851,890 64,313 — 11,874,518 Equity securities Common stocks 585 — — — 585 Exchange-traded funds 271,608 — — — 271,608 Bond mutual funds — 146,670 — — 146,670 272,193 146,670 — — 418,863 Other investments Hedge funds (1) — — — 184,747 184,747 Direct lending funds — — — 272,752 272,752 Private equity funds — — — 61,526 61,526 Real estate funds — — — 111,169 111,169 Other privately held investments — — 47,685 — 47,685 CLO-Equities — — 18,022 — 18,022 Overseas deposits — 99,430 — — 99,430 — 99,430 65,707 630,194 795,331 Short-term investments — 41,853 — — 41,853 Other assets Derivative instruments (refer to Note 5) — 3,468 — — 3,468 Total Assets $ 2,230,508 $ 10,143,311 $ 130,020 $ 630,194 $ 13,134,033 Liabilities Derivative instruments (refer to Note 5) $ — $ 3,604 $ 10,233 $ — $ 13,837 Cash settled awards (refer to Note 8) — 7,878 — — 7,878 Total Liabilities $ — $ 11,482 $ 10,233 $ — $ 21,715 (1) Includes Long/short equity, Multi-strategy and Event-driven funds. Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Fair value based on NAV practical expedient Total fair value At December 31, 2018 Assets Fixed maturities U.S. government and agency $ 1,480,466 $ 35,231 $ — $ — $ 1,515,697 Non-U.S. government — 493,016 — — 493,016 Corporate debt — 4,827,909 49,012 — 4,876,921 Agency RMBS — 1,643,308 — — 1,643,308 CMBS — 1,073,396 19,134 — 1,092,530 Non-Agency RMBS — 40,687 — — 40,687 ABS — 1,619,070 18,533 — 1,637,603 Municipals — 135,585 — — 135,585 1,480,466 9,868,202 86,679 — 11,435,347 Equity securities Common stocks 527 — — — 527 Exchange-traded funds 236,839 — — — 236,839 Bond mutual funds — 144,267 — — 144,267 237,366 144,267 — — 381,633 Other investments Hedge funds (1) — — — 194,598 194,598 Direct lending funds — — — 274,478 274,478 Private equity funds — — — 64,566 64,566 Real estate funds — — — 84,202 84,202 Other privately held investments — — 44,518 — 44,518 CLO-Equities — — 21,271 — 21,271 Overseas deposits — 104,154 — — 104,154 — 104,154 65,789 617,844 787,787 Short-term investments — 144,040 — — 144,040 Other assets Derivative instruments (refer to Note 5) — 8,237 — — 8,237 Total Assets $ 1,717,832 $ 10,268,900 $ 152,468 $ 617,844 $ 12,757,044 Liabilities Derivative instruments (refer to Note 5) $ — $ 4,223 $ 10,299 $ — $ 14,522 Cash settled awards (refer to Note 8) — 20,648 — — 20,648 Total Liabilities $ — $ 24,871 $ 10,299 $ — $ 35,170 (1) Includes Long/short equity, Multi-strategy and Event-driven funds. The following table quantifies the significant unobservable inputs used in estimating fair values at March 31, 2019 of investments classified as Level 3 in the fair value hierarchy. Fair value Valuation technique Unobservable input Range Weighted average Other investments - CLO-Equities $ 18,022 Discounted cash flow Default rates 3.0% 3.0% Loss severity rate 35.0% 35.0% Collateral spreads 3.0% 3.0% Estimated maturity dates 7 years 7 years Other investments - Other privately held investments $ 47,685 Discounted cash flow Discount rate 3.0% - 8.0% 6.5% Derivatives - Other underwriting-related derivatives $ (10,233 ) Discounted cash flow Discount rate 2.3% 2.3% Note: Fixed maturities and insurance-linked securities that are classified as Level 3 are excluded from the above table as these securities are priced using broker-dealer quotes. Other Investments - CLO-Equities The CLO-Equities market continues to be relatively inactive with only a small number of transactions being observed, particularly as it relates to transactions involving CLO-Equities held by the Company. Accordingly, the fair value of the Company's indirect investment in CLO-Equities is determined using a discounted cash flow model prepared by an external investment manager. The default and loss severity rates are the most judgmental unobservable market inputs to the discounted cash flow model to which the valuation of the Company's indirect investment in CLO-Equities is most sensitive. A significant increase (decrease) in either of these significant inputs in isolation would result in a lower (higher) fair value estimate for the investment in CLO-Equities and, in general, a change in default rate assumptions would be accompanied by a directionally similar change in loss severity rate assumptions. Collateral spreads and estimated maturity dates are less judgmental inputs as they are based on the historical average of actual spreads and the weighted average life of the current underlying portfolios, respectively. A significant increase (decrease) in either of these significant inputs in isolation would result in a higher (lower) fair value estimate for the investment 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, the Company's valuation process for its indirect investment in CLO-Equities includes a review of the underlying cash flows and key assumptions used in the discounted cash flow model. The above significant unobservable inputs are reviewed and updated based on information obtained from secondary markets, including information received from the managers of the Company's CLO-Equities portfolio. In order to assess the reasonableness of the inputs the Company uses in its models, the Company maintains an understanding of current market conditions, historical results, as well as emerging trends that may impact future cash flows. In addition, the assumptions the Company uses in its models are updated through regular communication with industry participants and ongoing monitoring of the deals in which the Company participates (e.g. default and loss severity rate trends). Other Investments - Other Privately Held Securities Other privately held securities are initially valued at cost which approximates fair value. In subsequent measurement periods, the fair values of these securities are determined using internally developed discounted cash flow models. These models include inputs that are specific to each investment. The inputs used in the fair value measurements include dividend or interest rates and appropriate discount rates. The selection of an appropriate discount rate is judgmental and is the most significant unobservable input used in the valuation of these securities. A significant increase (decrease) in this input in isolation could result in significantly lower (higher) fair value measurement for other privately held securities. Where relevant, the Company also considers the contractual agreements which stipulate methodologies for calculating the dividend rate to be paid upon liquidation, conversion or redemption. In order to assess the reasonableness of the inputs the Company uses in the discounted cash flow models, the Company maintains an understanding of current market conditions, historical results, as well as investee specific information that may impact future cash flows. Derivatives - Other Underwriting-related Derivatives Other underwriting-related derivatives are initially valued at cost which approximates fair value. In subsequent measurement periods, the fair values of these derivatives are determined using internally developed discounted cash flow models which uses appropriate discount rates. The selection of an appropriate discount rate is judgmental and is the most significant unobservable input used in the valuation of these derivatives. A significant increase (decrease) in this input in isolation could result in a significantly lower (higher) fair value measurement for the derivative contracts. In order to assess the reasonableness of the inputs the Company uses in the discounted cash flow model, the Company maintains an understanding of current market conditions, historical results, as well as contract specific information that may impact future cash flows. The following tables present changes in Level 3 for financial instruments measured at fair value on a recurring basis for the periods indicated: Opening balance Transfers into Level 3 Transfers out of Level 3 Included in net income (1) Included in OCI (2) Purchases Sales Settlements/ distributions Closing balance Change in unrealized investment gains/(losses) (3) Three months ended March 31, 2019 Fixed maturities Corporate debt $ 49,012 $ — $ — $ (696 ) $ 624 $ — $ (5,547 ) $ (2,268 ) $ 41,125 $ — CMBS 19,134 — (4,767 ) — 143 — — (3,365 ) 11,145 — ABS 18,533 — (16,402 ) — 162 9,750 — — 12,043 — 86,679 — (21,169 ) (696 ) 929 9,750 (5,547 ) (5,633 ) 64,313 — Other investments Other privately held investments 44,518 — — 667 — 2,500 — — 47,685 667 CLO - Equities 21,271 — — 415 — — — (3,664 ) 18,022 415 65,789 — — 1,082 — 2,500 — (3,664 ) 65,707 1,082 Other assets Insurance-linked securities — — — — — — — — — — — — — — — — — — — — Total assets $ 152,468 $ — $ (21,169 ) $ 386 $ 929 $ 12,250 $ (5,547 ) $ (9,297 ) $ 130,020 $ 1,082 Other liabilities Derivative instruments $ 10,299 $ — $ — $ (66 ) $ — $ — $ — $ — $ 10,233 $ (66 ) Total liabilities $ 10,299 $ — $ — $ (66 ) $ — $ — $ — $ — $ 10,233 $ (66 ) Opening balance Transfers into Level 3 Transfers out of Level 3 Included in net income (1) Included in OCI (2) Purchases Sales Settlements/ distributions Closing balance Change in unrealized investment gains/(losses) (3) Three months ended March 31, 2018 Fixed maturities Corporate debt $ 52,897 $ — $ (4,279 ) $ (118 ) $ 1,403 $ — $ (2,536 ) $ (3,896 ) $ 43,471 $ — CMBS — — — — — — — — — — ABS — — — — — — — — — — 52,897 — (4,279 ) (118 ) 1,403 — (2,536 ) (3,896 ) 43,471 — Other investments Other privately held investments 46,430 — — 746 — 3,111 (1,500 ) — 48,787 746 CLO - Equities 31,413 — — 1,616 — — — (4,473 ) 28,556 1,616 77,843 — — 2,362 — 3,111 (1,500 ) (4,473 ) 77,343 2,362 Other assets Insurance-linked securities 25,090 — — (90 ) — — — — 25,000 (90 ) 25,090 — — (90 ) — — — — 25,000 (90 ) Total assets $ 155,830 $ — $ (4,279 ) $ 2,154 $ 1,403 $ 3,111 $ (4,036 ) $ (8,369 ) $ 145,814 $ 2,272 Other liabilities Derivative instruments $ 11,510 $ — $ — $ (568 ) $ — $ — $ — $ — $ 10,942 $ (568 ) Total liabilities $ 11,510 $ — $ — $ (568 ) $ — $ — $ — $ — $ 10,942 $ (568 ) (1) Realized investment gains (losses) on fixed maturities, and realized and unrealized gains (losses) on other assets and other liabilities included in net income are included in net investment gains (losses). Realized and unrealized gains (losses) on other investments included in net income are included in net investment income. (2) Unrealized investment gains (losses) on fixed maturities are included in other comprehensive income ("OCI"). (3) Change in unrealized investment gains (losses) relating to assets held at the reporting date. Transfers into Level 3 from Level 2 There were no transfers into Level 3 from Level 2 made during the three months ended March 31, 2019 and 2018. Transfers out of Level 3 into Level 2 The transfers out of Level 3 into Level 2 made during the three months ended March 31, 2019 and 2018 were primarily due to the availability of observable market inputs and multiple quotes from pricing vendors for certain fixed maturities. Measuring the Fair Value of Other Investments Using Net Asset Valuations The fair values of hedge funds, direct lending funds, private equity funds and real estate funds are estimated using NAVs as advised by external fund managers or third party administrators. For these funds, NAVs are based on the manager's or administrator's valuation of the underlying holdings in accordance with the fund's governing documents and in accordance with U.S. GAAP. If there is a reporting lag between the current period end and reporting date of the latest available fund valuation for any hedge fund, the Company estimates fair values by starting with the most recently available fund valuation and adjusting for return estimates as well as any subscriptions, redemptions and distributions that took place during the current period. Return estimates are obtained from the relevant fund managers therefore the Company does not typically have a reporting lag in fair value measurements of these funds. Historically, the Company's valuation estimates incorporating these return estimates have not significantly diverged from the subsequently received NAVs. For direct lending funds, private equity funds, real estate funds and two of the Company's hedge funds, valuation statements are typically released on a reporting lag therefore the Company estimates the fair value of these funds by starting with the most recent fund valuations and adjusting for capital calls, redemptions, drawdowns and distributions. Return estimates are not available from the relevant fund managers for these funds therefore the Company typically has a reporting lag in its fair value measurements of these funds. For the three months ended March 31, 2019 , funds reported on a lag represented 62% (2018: 61% ) of the Company's total other investments balance. The Company often does not have access to financial information relating to the underlying securities held within the funds, therefore management is unable to corroborate the fair values placed on the securities underlying the asset valuations provided by fund managers or fund administrators. In order to assess the reasonableness of the NAVs, the Company performs a number of monitoring procedures on a quarterly basis, to assess the quality of the information provided by fund managers and fund administrators. These procedures include, but are not limited to, regular review and discussion of each fund's performance with its manager, regular evaluation of fund performance against applicable benchmarks and the backtesting of the Company's fair value estimates against subsequently received NAVs. Backtesting involves comparing the Company's previously reported fair values for each fund against NAVs per audited financial statements (for year-end values) and final NAVs from fund managers and fund administrators (for interim values). The fair values of hedge funds, direct lending funds, private equity funds and real estate funds are measured using the NAV practical expedient, therefore the fair values of these funds have not been categorized within the fair value hierarchy. Financial Instruments Disclosed, But Not Carried, at Fair Value The fair value of financial instruments accounting guidance also applies to financial instruments disclosed, but not carried, at fair value, except for certain financial instruments, including insurance contracts. At March 31, 2019 , the carrying values of cash and cash equivalents including restricted amounts, accrued investment income, receivable for investments sold, certain other assets, payable for investments purchased and certain other liabilities approximated their fair values due to their respective short maturities. As these financial instruments are not actively traded, their fair values are classified as Level 2. At March 31, 2019 , the carrying value of mortgage loans held-for-investment approximated their fair value. The fair values of mortgage loans are primarily determined by estimating expected future cash flows and discounting them using current interest rates for similar mortgage loans with similar credit risk, or are determined from pricing for similar loans. As mortgage loans are not actively traded their fair values are classified as Level 3. At March 31, 2019 , senior notes are recorded at amortized cost with a carrying value of $1,342 million ( 2018 : $1,342 million ) and a fair value of $1,360 million ( 2018 : $1,334 million ). The fair values of these senior notes are based on prices obtained from a third party pricing service and are determined using the spread above the risk-free yield curve. These spreads are generally obtained from the new issue market, secondary trading and broker-dealer quotes. As the yields for the risk-free yield curve and the spreads are observable market inputs, the fair values of senior notes are classified as Level 2.

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	The balance sheet classifications of derivatives recorded at fair value are shown in the following table. March 31, 2019 December 31, 2018 Derivative notional amount Derivative asset fair value (1) Derivative liability fair value (1) Derivative notional amount Derivative asset fair value (1) Derivative liability fair value (1) Relating to investment portfolio: Foreign exchange forward contracts $ 172,306 $ 818 $ 284 $ 79,336 $ 262 $ 531 Interest rate swaps 85,000 984 — 150,000 — 1,116 Relating to underwriting portfolio: Foreign exchange forward contracts 543,174 1,666 3,320 737,419 7,975 2,576 Other underwriting-related contracts 85,000 — 10,233 85,000 — 10,299 Total derivatives $ 3,468 $ 13,837 $ 8,237 $ 14,522 (1) Asset and liability derivatives are classified within other assets and other liabilities in the consolidated balance sheets. The notional amounts of derivative contracts which represent the basis upon which pay or receive amounts are calculated and are presented in the above table to quantify the volume of the Company's derivative activities. Notional amounts are not reflective of credit risk. None of the Company's derivative instruments are designated as hedges under current accounting guidance. Offsetting Assets and Liabilities The Company's derivative instruments are generally traded under International Swaps and Derivatives Association master netting agreements, which establish terms that apply to all transactions. In the event of a bankruptcy or other stipulated event, master netting agreements provide that individual positions be replaced with a new amount, usually referred to as the termination amount, determined by taking into account market prices and converting into a single currency. Effectively, this contractual close-out netting reduces credit exposure from gross to net exposure. A reconciliation of gross derivative assets and liabilities to the net amounts presented in the consolidated balance sheets, with the difference being attributable to the impact of master netting agreements, is shown in the following table. March 31, 2019 December 31, 2018 Gross amounts Gross amounts offset Net amounts (1) Gross amounts Gross amounts offset Net amounts (1) Derivative assets $ 6,115 $ (2,647 ) $ 3,468 $ 11,967 $ (3,730 ) $ 8,237 Derivative liabilities $ 16,484 $ (2,647 ) $ 13,837 $ 18,252 $ (3,730 ) $ 14,522 (1) Net asset and liability derivatives are classified within other assets and other liabilities in the consolidated balance sheets. Refer to Note 3 'Investments' for information on reverse repurchase agreements. a) Relating to Investment Portfolio Foreign Currency Risk The Company's investment portfolio is exposed to foreign currency risk therefore the fair values of its investments are partially influenced by the change in foreign exchange rates. The Company may enter into foreign currency forward contracts to manage the effect of this foreign currency risk. These foreign currency hedging activities are not designated as specific hedges for financial reporting purposes. Interest Rate Risk The Company's investment portfolio contains a large percentage of fixed maturities which exposes it to significant interest rate risk. As part of overall management of this risk, the Company may use interest rate swaps. b) Relating to Underwriting Portfolio Foreign Currency Risk The Company's (re)insurance subsidiaries and branches operate in various countries. Some of its business is written in currencies other than the U.S. dollar, therefore the underwriting portfolio is exposed to significant foreign currency risk. The Company manages foreign currency risk by seeking to match its foreign-denominated net liabilities under (re)insurance contracts with cash and investments that are denominated in the same currencies. The Company uses derivative instruments, specifically, forward contracts to economically hedge foreign currency exposures. Other Underwriting-related Risks The Company enters into insurance and reinsurance contracts that are accounted for as derivatives. These insurance or reinsurance contracts provide indemnification to an insured or cedant as a result of a change in a variable as opposed to an identifiable insurable event. The Company considers these contracts to be part of its underwriting operations. The total unrealized and realized gains (losses) recognized in net income for derivatives not designated as hedges are shown in the following table: Location of gain (loss) recognized in net income Three months ended March 31, 2019 2018 Relating to investment portfolio: Foreign exchange forward contracts Net investment gains (losses) $ 752 $ (1,191 ) Interest rate swaps Net investment gains (losses) (2,854 ) 3,214 Relating to underwriting portfolio: Foreign exchange forward contracts Foreign exchange gains (losses) (10,517 ) 7,768 Other underwriting-related contracts Other insurance related income (losses) 347 901 Total $ (12,272 ) $ 10,692

RESERVE FOR LOSSES AND LOSS EXP

RESERVE FOR LOSSES AND LOSS EXPENSES	3 Months Ended
	Mar. 31, 2019
Insurance Loss Reserves [Abstract]
RESERVE FOR LOSSES AND LOSS EXPENSES	Reserve Roll-Forward The following table presents a reconciliation of the Company's beginning and ending gross reserve for losses and loss expenses and net reserve for unpaid losses and loss expenses for the periods indicated: Three months ended March 31, 2019 2018 Gross reserve for losses and loss expenses, beginning of period $ 12,280,769 $ 12,997,553 Less reinsurance recoverable on unpaid losses, beginning of period (3,501,669 ) (3,159,514 ) Net reserve for unpaid losses and loss expenses, beginning of period 8,779,100 9,838,039 Net incurred losses and loss expenses related to: Current year 678,700 715,652 Prior years (14,672 ) (54,307 ) 664,028 661,345 Net paid losses and loss expenses related to: Current year (37,600 ) (48,814 ) Prior years (691,558 ) (675,393 ) (729,158 ) (724,207 ) Foreign exchange and other 6,460 (726,781 ) Net reserve for unpaid losses and loss expenses, end of period 8,720,430 9,048,396 Reinsurance recoverable on unpaid losses, end of period 3,555,341 2,986,247 Gross reserve for losses and loss expenses, end of period $ 12,275,771 $ 12,034,643 The Company writes business with loss experience generally characterized as low frequency and high severity in nature, which can result in volatility in its financial results. During the three months ended March 31, 2019 , the Company recognized net losses and loss expenses of $11 million ( 2018 : $35 million ) attributable to catastrophe and weather-related events. On January 1, 2018, AXIS Managing Agency Limited, the managing agent of Syndicate 2007 entered into an agreement for the RITC of the 2015 and prior years of account of Syndicate 2007. This agreement was accounted for as a novation reinsurance contract. At March 31, 2018 , foreign exchange and other included a reduction in reserves for losses and loss expenses of $819 million related to this transaction. Prior Year Development The Company's net favorable prior year reserve development arises from changes to loss and loss expense estimates related to loss events that occurred in previous calendar years. The following table presents net prior year reserve development by segment: Three months ended March 31, 2019 2018 Insurance $ 6,913 $ 22,775 Reinsurance 7,759 31,532 Total $ 14,672 $ 54,307 The following tables map the Company's line of business to reserve classes and the expected claim tails: Insurance segment Reserve class and tail Property and other Marine Aviation Credit and political risk Professional lines Liability Short Short Short/Medium Medium Medium Long Reported lines of business Property X Marine X Terrorism X Aviation X Credit and political risk X Professional lines X Liability X Accident and health X Discontinued lines - Novae X X X Reinsurance segment Reserve class and tail Property and other Credit and surety Professional lines Motor Liability Short Medium Medium Long Long Reported lines of business Catastrophe X Property X Credit and surety X Professional lines X Motor X Liability X Engineering X Agriculture X Marine and other X Accident and health X Discontinued lines - Novae X X X Short-tail business Short-tail business includes the underlying exposures in property and other, marine and aviation reserve classes within the insurance segment, and the property and other reserve class within the reinsurance segment. For the three months ended March 31, 2019 , these reserve classes recognized net adverse prior year reserve development of $33 million including $22 million of net adverse prior year reserve development recognized by the insurance property and other reserve class and $29 million of net adverse prior year reserve development recognized by the reinsurance property and other reserve class, partially offset by net favorable prior year development of $16 million contributed by the insurance marine class. For the three months ended March 31, 2018 , these reserve classes contributed net favorable prior year reserve development of $37 million reflecting the recognition of better than expected loss emergence. Medium-tail business Medium-tail business consists primarily of insurance and reinsurance professional lines reserve classes, credit and political risk insurance reserve class and credit and surety reinsurance reserve class. For the three months ended March 31, 2019 , the credit and surety reinsurance reserve class recorded net favorable prior year reserve development of $10 million ( 2018 : $6 million ) reflecting the recognition of better than expected loss emergence. For the three months ended March 31, 2019 , the insurance professional lines reserve class recognized net favorable prior year development of $6 million ( 2018 : $4 million ). For the three months ended March 31, 2018 , the reinsurance professional lines reserve class recognized net favorable prior year reserve development of $9 million . The net favorable prior year loss development on these reserve classes continued to reflect generally favorable experience on older accident years as the Company continued to transition to more experienced based methods. Long-tail business Long-tail business consists primarily of insurance and reinsurance liability reserve classes and reinsurance motor reserve classes. For the three months ended March 31, 2019 , the reinsurance liability reserve class contributed net favorable prior year reserve development of $12 million ( 2018 : $2 million ). For the three months ended March 31, 2019 , the net favorable prior year reserve development was due to increased weight given by management to experience based indications on older accident years. For the three months ended March 31, 2018 , the insurance liability reserve class recorded net adverse prior year development of $7 million primarily related to reserve strengthening within the Company's U.S. excess casualty book of business reflecting slightly higher than expected prior year emerging loss experience. For the three months ended March 31, 2019 , the motor reinsurance reserve class contributed net favorable prior year reserve development of $12 million ( 2018 : $3 million ). For the three months ended March 31, 2019 , the net favorable prior year reserve development was primarily attributable to non proportional treaty business on older accident years. At March 31, 2019 , net reserves for losses and loss expenses included estimated amounts for numerous catastrophe events. The magnitude and/or complexity of losses arising from these events, in particular California Wildfires, Hurricanes Michael and Florence, and Typhoons Jebi and Trami which occurred in 2018 as well as Hurricanes Harvey, Irma and Maria, the two earthquakes in Mexico and the California Wildfires which occurred in 2017 inherently increase the level of uncertainty and, therefore, the level of management judgment involved in arriving at the estimated net reserves for losses and loss expenses. As a result, actual losses for these events may ultimately differ materially from the Company's current estimates.

EARNINGS PER COMMON SHARE

EARNINGS PER COMMON SHARE	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
EARNINGS PER COMMON SHARE	The following table presents a comparison of earnings per common share and earnings per diluted common share: Three months ended March 31, 2019 2018 Earnings per common share Net income $ 108,781 $ 73,202 Less: Preferred share dividends 10,656 10,656 Net income available to common shareholders 98,125 62,546 Weighted average common shares outstanding 83,725 83,322 Earnings per common share $ 1.17 $ 0.75 Earnings per diluted common share Net income available to common shareholders $ 98,125 $ 62,546 Weighted average common shares outstanding 83,725 83,322 Share-based compensation plans 547 399 Weighted average diluted common shares outstanding 84,272 83,721 Earnings per diluted common share $ 1.16 $ 0.75 Weighted average anti-dilutive shares excluded from the dilutive computation 601 810

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
SHARE-BASED COMPENSATION	For the three months ended March 31, 2019 , the Company incurred share-based compensation costs of $15 million ( 2018 : $16 million ) related to share-settled restricted stock units and cash-settled restricted stock units. In addition, the Company recorded associated tax benefits of $2 million ( 2018 : $2 million ). During the three months ended March 31, 2019 , the fair value of share-settled restricted stock units and cash-settled restricted stock units that vested was $48 million ( 2018 : $42 million ). At March 31, 2019 there was $121 million of unrecognized share-based compensation costs ( 2018 : $137 million ) which are expected to be recognized over the weighted average period of 2.9 years ( 2018 3.0 years ). Share-Settled Awards The following table provides an activity summary of the Company's share-settled restricted stock units for the three months ended March 31, 2019 : Share-Settled Performance Vesting Restricted Stock Units Share-Settled Service Based Restricted Stock Units Number of restricted stock units Weighted average grant date fair value (1) Number of restricted stock units Weighted average grant date fair value (1) Nonvested restricted stock units - beginning of period 232 $ 54.54 1,411 $ 54.12 Granted 127 54.70 508 54.67 Vested (61 ) 53.82 (445 ) 54.04 Forfeited — — (74 ) 54.84 Nonvested restricted stock units - end of period 298 $ 54.76 1,400 $ 54.31 (1) Fair value is based on the closing price of the Company's common shares on the grant date. Cash-Settled awards The following table provides an activity summary of the Company's cash-settled restricted stock units for the three months ended March 31, 2019 : Cash-Settled Performance Vesting Restricted Stock Units Cash-Settled Service Based Restricted Stock Units Number of restricted stock units Number of restricted stock units Nonvested restricted stock units - beginning of period 27 932 Granted — 349 Vested (12 ) (320 ) Forfeited — (35 ) Nonvested restricted stock units - end of period 15 926 At March 31, 2019 , the liability for cash-settled restricted stock units, included in other liabilities in the consolidated balance sheet, was $8 million (2018: $9 million ).

SHAREHOLDERS' EQUITY

SHAREHOLDERS' EQUITY	3 Months Ended
	Mar. 31, 2019
Stockholders' Equity Note [Abstract]
SHAREHOLDERS' EQUITY	The following table presents changes in common shares issued and outstanding: Three months ended March 31, 2019 2018 Shares issued, balance at beginning of period 176,580 176,580 Shares issued — — Total shares issued at end of period 176,580 176,580 Treasury shares, balance at beginning of period (92,994 ) (93,419 ) Shares repurchased (157 ) (149 ) Shares reissued 505 506 Total treasury shares at end of period (92,646 ) (93,062 ) Total shares outstanding 83,934 83,518 In the three months ended March 31, 2019 , the total cash dividends declared per common share were $0.40 ( 2018 : $0.39 ). In the three months ended March 31, 2019 , the total dividends declared on Series D preferred shares were $0.34375 per share, payable in June 2019 ( 2018 : $0.34375 , paid in June 2018). In the three months ended March 31, 2019 , the total dividends declared on Series E preferred shares were $34.375 per share, paid in April 2019 ( 2018 : $34.375 , paid in April 2018). Treasury Shares The following table presents common share repurchased from shares held in Treasury: Three months ended March 31, 2019 2018 In the open market: Total shares — — Total cost $ — $ — Average price per share (1) $ — $ — From employees: (2) Total shares 157 149 Total cost $ 9,003 $ 7,163 Average price per share (1) $ 57.17 $ 48.08 Total shares repurchased: Total shares 157 149 Total cost $ 9,003 $ 7,163 Average price per share (1) $ 57.17 $ 48.08 (1) Calculated using whole numbers. (2) Shares are repurchased from employees to satisfy withholding tax liabilities related to the vesting of share-settled restricted stock units.

DEBT AND FINANCING ARRANGEMENTS

DEBT AND FINANCING ARRANGEMENTS	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
DEBT AND FINANCING ARRANGEMENTS	On March 28, 2019, certain of AXIS Capital’s operating subsidiaries (the "Participating Subsidiaries") amended their existing $250 million secured letter of credit facility with Citibank Europe plc (the " $250 Million Facility") under their aggregate $750 million secured letter of credit facility with Citibank Europe plc (the " $750 Million Facility") to extend the expiration date to March 31, 2020. The terms and conditions of the additional $500 million secured letter of credit facility under the $750 Million Facility remain unchanged. The $500 million secured letter of credit facility expires December 31, 2019. Letters of credit issued under the $750 Million Facility will principally be used to support the reinsurance obligations of the Participating Subsidiaries. The Participating Subsidiaries are subject to certain covenants, including the requirement to maintain sufficient collateral to cover obligations outstanding under the $750 Million Facility. In the event of default, Citibank Europe plc may exercise certain remedies, including the exercise of control over pledged collateral and the termination of the availability of the $750 Million Facility to any or all of the Participating Subsidiaries.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	Legal Proceedings From time to time, the Company is subject to routine legal proceedings, including arbitrations, arising in the ordinary course of business. These legal proceedings generally relate to claims asserted by or against the Company in the ordinary course of insurance or reinsurance operations. Estimated amounts payable under such proceedings are included in the reserve for losses and loss expenses in the consolidated balance sheets. The Company is not party to any material legal proceedings arising outside the ordinary course of business. Investments Refer to Note 3 - 'Investments' for information on the Company's unfunded investment commitments related to the Company's other investment portfolio.

LEASES

LEASES	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
LEASES	In the ordinary course of business, the Company renews and enters into new leases for office property and equipment, which expire at various dates. At the lease inception date, the Company assesses whether a contract is or contains a lease. At the commencement date, the Company determines the classification of each separate lease component as either a finance lease or an operating lease. The Company's leases are all currently classified as operating leases. For operating leases that have a lease term of more than 12 months, the Company recognizes a lease liability and a right-of-use asset in the Company's consolidated balance sheets at the present value of the lease payments at the lease commencement date. At the commencement date, the Company determines lease terms by assuming the exercise of those renewal options that are deemed to be reasonably certain. The exercise of lease renewal options is at the sole discretion of the Company. As the lease contracts generally do not provide an implicit discount rate, the Company uses its incremental borrowing rate based on the information available at commencement date to determine the present value of lease payments. The incremental borrowing rate is based on a borrowing with a term that is similar to the term of the associated lease. The Company has made an accounting policy election not to include renewal, termination, or purchase options that are not reasonably certain of exercise when determining the term of the borrowing. The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants. Operating lease rentals are expensed on a straight-line basis over the life of the lease beginning on the commencement date. For the three months ended March 31, 2019 , the total lease expense was $7 million . The following table summarizes the amounts related to the Company’s total lease expense and the cash flows arising from lease transactions. Three months ended March 31, 2019 Lease cost: Operating lease expense $ 6,930 Short-term lease expense (1) 646 Sublease income (2) (542 ) Total lease expense $ 7,034 Other information: Operating cash outflows from operating leases $ 6,536 Right-of-use assets obtained in exchange for new operating lease liabilities $ — Weighted-average remaining lease term - operating leases (3) 8.8 years Weighted-average discount rate - operating lease (4) 4.7 % (1) Short-term lease expense is recognized on a straight-line basis over the lease term. (2) Sublease income largely relates to office property in London, England. (3) Weighted-average remaining lease term was calculated on the basis of the remaining lease term and the lease liability balance for each lease at the reporting date. (4) Weighted-average discount was calculated on the basis of the discount rate for the lease that was used to calculate the lease liability balance for each lease at the reporting date and the remaining balance of the lease payments for each lease at the reporting date. At March 31, 2019 , the scheduled maturity of the Company's operating lease liabilities are expected to be as follows: Expected Cash Flows Remainder of 2019 $ 19,818 2020 22,545 2021 22,451 2022 23,165 2023 19,042 Later years 72,536 Discount (35,259 ) Total discounted operating lease liabilities $ 144,298 The Company's lease for its current office property in Alpharetta, Georgia, expires on December 31, 2019. As a result, the Company executed a 15 year lease for a new office property in Alpharetta, Georgia. The Company is not involved in the construction or design of this office property and will not move into this property until January 1, 2020, the commencement date of the lease. Given that the commencement date is after the balance sheet date, the Company has not reflected this lease in the maturity table above or in the Company's consolidated balance sheets at March 31, 2019 . The total contractual lease costs over the 15 year lease is $40 million . At December 31, 2018, the Company's future minimum lease payments were expected to be as follows: Year ended December 31, 2019 $ 28,240 2020 25,331 2021 27,025 2022 28,012 2023 23,801 Later years 118,497 Total future minimum lease payments $ 250,906 For the three months ended March 31, 2018 , the total lease expense was $7 million .

TRANSACTION AND REORGANIZATION

TRANSACTION AND REORGANIZATION EXPENSES	3 Months Ended
	Mar. 31, 2019
Restructuring and Related Activities [Abstract]
TRANSACTION AND REORGANIZATION EXPENSES	During the three months ended March 31, 2019 , the Company recognized transaction and reorganization expenses of $15 million (2018: $13 million ) related to its transformation program which was launched in 2017. This program encompasses the integration of Novae which commenced in the fourth quarter of 2017, the realignment of the Company's accident and health business, together with other initiatives designed to increase efficiency and enhance profitability while delivering a customer-centric operating model.

OTHER COMPREHENSIVE INCOME (LOS

OTHER COMPREHENSIVE INCOME (LOSS)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
OTHER COMPREHENSIVE INCOME (LOSS)	The following table presents the tax effects allocated to each component of other comprehensive income (loss): 2019 2018 Before tax amount Tax (expense) benefit Net of tax amount Before tax amount Tax (expense) benefit Net of Tax Amount Three months ended March 31, Available for sale investments: Unrealized investment gains (losses) arising during the period $ 206,806 $ (16,633 ) $ 190,173 $ (105,675 ) $ (6,516 ) $ (112,191 ) Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income 13,874 (504 ) 13,370 (4,112 ) 4,897 785 Unrealized investment gains (losses) arising during the period, net of reclassification adjustment 220,680 (17,137 ) 203,543 (109,787 ) (1,619 ) (111,406 ) Non-credit portion of OTTI losses — — — — — — Foreign currency translation adjustment 2,662 — 2,662 1,270 — 1,270 Total other comprehensive income (loss), net of tax $ 223,342 $ (17,137 ) $ 206,205 $ (108,517 ) $ (1,619 ) $ (110,136 ) The following table presents reclassifications from accumulated other comprehensive income ("AOCI") to net income available to common shareholders: Amount reclassified from AOCI (1) Details about AOCI Components Consolidated statement of operations line item that includes reclassification Three months ended March 31, 2019 2018 Unrealized investment gains (losses) on available for sale investments Other realized investment gains (losses) $ (9,838 ) $ 4,526 OTTI losses (4,036 ) (414 ) Total before tax (13,874 ) 4,112 Income tax (expense) benefit 504 (4,897 ) Net of tax $ (13,370 ) $ (785 ) (1) Amounts in parentheses are debits to net income (loss) available (attributable) to common shareholders.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	On April 1, 2019, AXIS Specialty Finance PLC, a 100% owned finance subsidiary, repaid $250 million aggregate principal amount of 2.65% Senior Notes. On April 3, 2019, AXIS Capital and AXIS Specialty Finance PLC ("AXIS Finance") entered into a first supplemental indenture (the "First Supplemental Indenture") among AXIS Finance, as issuer, AXIS Capital, as guarantor, and The Bank of New York Mellon Trust Company, N.A., as trustee (the "Trustee"), to the senior indenture dated March 13, 2014 (the "Indenture") relating to $250 million aggregate principal amount of 5.15% Senior Notes due 2045 (the " 5.15% Senior Notes") issued by AXIS Finance and fully and unconditionally guaranteed by AXIS Capital. The changes described below were made to permit the 5.15% Senior Notes to qualify as Tier 3 ancillary capital under eligible capital requirements of the Bermuda Monetary Authority. Because this amendment does not materially adversely affect the interests of the holders of the 5.15% Senior Notes, the First Supplemental Indenture was entered into without consent of any holders of the 5.15% Senior Notes. The First Supplemental Indenture relates to the 5.15% Senior Notes only and does not affect any other series of securities issued under the Indenture. Under the terms of the senior indenture, the 5.15% Senior Notes are redeemable at any time at the option of AXIS Finance at a redemption price equal to a make-whole premium or, in the event that, as a result of certain tax law changes, AXIS Finance or AXIS Capital becomes obligated to pay additional amounts with respect to the 5.15% Senior Notes, at par, plus in each case, accrued and unpaid interest. The First Supplemental Indenture limits this optional redemption right to provide that the 5.15% Senior Notes are not redeemable at the option of AXIS Finance on or before March 13, 2017, except in the limited circumstances set forth in the First Supplemental Indenture and prior to maturity unless certain conditions are satisfied. The First Supplemental Indenture also clarifies, for the avoidance of doubt, that the 5.15% Senior Notes are free of encumbrances and that neither the Indenture nor the 5.15% Senior Notes contain any terms or conditions designed to accelerate or induce AXIS Capital or any of its subsidiary’s insolvency or effect similar proceedings. The holders of the 5.15% Senior Notes should note that the 5.15% Senior Notes do not in any way give rise to any rights of set-off against any claims and obligations of AXIS Capital, AXIS Finance or any of AXIS Capital’s regulated operating subsidiaries to any holder or creditor.

BASIS OF PRESENTATION AND SIG_2

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation These unaudited Consolidated Financial Statements (the "financial statements") have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") for interim financial information and with the U.S. Securities and Exchange Commission's ("SEC") instructions to Form 10-Q and Article 10 of Regulation S-X and include AXIS Capital Holdings Limited ("AXIS Capital") and its subsidiaries (the "Company"). Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. This Quarterly Report on Form 10-Q should be read in conjunction with the financial statements and related notes included in AXIS Capital's Annual Report on Form 10-K for the year ended December 31, 2018 , as filed with the SEC. In the opinion of management, these financial statements reflect all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the Company's financial position and results of operations for the periods presented. The results of operations for any interim period are not necessarily indicative of the results for a full year. All inter-company accounts and transactions have been eliminated. To facilitate comparison of information across periods, certain reclassifications have been made to prior year amounts to conform to the current year's presentation. These reclassifications did not impact results of operations, financial condition or liquidity. Tabular dollar and share amounts are in thousands, except per share amounts. All amounts are reported in U.S. dollars.
New Accounting Standards	Significant Accounting Policies There was no notable change to the Company's significant accounting policies subsequent to its Annual Report on Form 10-K for the year ended December 31, 2018 . New Accounting Standards Adopted in 2019 Leases Effective January 1, 2019, the Company adopted ASU 2016-02, "Leases (Topic 842)", which provides a new comprehensive model for lease accounting. Topic 842 requires a lessee to recognize a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. The adoption of this standard resulted in the recognition of lease liabilities and right-of-use assets of $144 million in the Company's consolidated balance sheet at March 31, 2019 , related to office property and equipment leases. In addition, the Company adopted ASU 2018-11, "Leases (Topic 842) - Targeted Improvements ", which provides an additional (and optional) transition method to adopt the new lease guidance. Under the alternative transition method, the Company's reporting for the comparative periods presented in its financial statements will be in accordance with the pre-effective date lease accounting requirements (Topic 840). The Company also elected the package of practical expedients permitted under the transition guidance of Topic 842, which were elected as a package and applied consistently to all leases. At the adoption date, the package of practical expedients permitted the Company not to reassess the following: 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. In addition to electing the package of practical expedients, the Company made an accounting policy election to account for non-lease components separately from lease components. As a result, the non-lease components associated with the Company's leases are not included in the lease liabilities and right-of-use assets in the Company's consolidated balance at March 31, 2019 . Further, the Company made an accounting policy election not to record office property and equipment leases with an initial term of 12 months or less (short-term) in the Company's consolidated balance sheets. For the three months ended March 31, 2019 , the Company recognized expense for short-term leases of $0.6 million in the Company's consolidated statements of operations. The adoption of this guidance did not impact the Company's retained earnings, results of operations, or liquidity. Premium Amortization on Purchased Callable Debt Securities Effective January 1, 2019, the Company adopted ASU 2017-08 "Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) - Premium Amortization on Purchased Callable Debt Securities" which shortens the amortization period for certain purchased callable debt securities held at a premium. The adoption of this guidance did not impact the Company's results of operations, financial condition or liquidity. Changes to Disclosures on Fair Value Measurement Effective January 1, 2019, the Company adopted ASU 2018-13 "Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement " which aims to improve the effectiveness of fair value measurement disclosures. The adoption of this guidance did not impact the Company's results of operations, financial condition or liquidity. Recently Issued Accounting Standards Not Yet Adopted Measurement of Credit Losses on Financial Instrument In June 2016, the FASB issued ASU 2016-13, "Financial Instruments - Credit Losses (Topic 326) - Measurement of Credit Losses on Financial Instruments " which replaces the "incurred loss" impairment methodology with an approach based on "expected losses" to estimate credit losses on certain types of financial instruments and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The guidance requires financial assets to be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the cost of the financial asset to present the net carrying value at the amount expected to be collected on the financial asset. Credit losses relating to available-for-sale debt securities will be recorded through an allowance for credit losses. The guidance also provides for a simplified accounting model for purchased financial assets with credit deterioration since their origination. This guidance is effective for interim and annual periods beginning after December 15, 2019. Early adoption is permitted for interim and annual periods beginning after December 15, 2018. The Company is currently evaluating the impact of this guidance on its results of operations, financial condition and liquidity.

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
UNDERWRITING RESULTS OF REPORTABLE SEGMENTS	The following tables present the underwriting results of the Company's reportable segments, as well as the carrying values of allocated goodwill and intangible assets: 2019 2018 Three months ended and at March 31, Insurance Reinsurance Total Insurance Reinsurance Total Gross premiums written $ 851,096 $ 1,732,130 $ 2,583,226 $ 880,848 $ 1,781,947 $ 2,662,795 Net premiums written 529,239 1,247,820 1,777,059 547,893 1,437,978 1,985,871 Net premiums earned 556,762 577,450 1,134,212 580,059 587,343 1,167,402 Other insurance related income 1,742 5,187 6,929 620 5,986 6,606 Net losses and loss expenses (313,776 ) (350,252 ) (664,028 ) (321,538 ) (339,807 ) (661,345 ) Acquisition costs (117,775 ) (142,643 ) (260,418 ) (87,329 ) (141,931 ) (229,260 ) General and administrative expenses (106,034 ) (32,839 ) (138,873 ) (102,370 ) (37,296 ) (139,666 ) Underwriting income $ 20,919 $ 56,903 77,822 $ 69,442 $ 74,295 143,737 Net investment income 107,303 100,999 Net investment gains (losses) 12,767 (14,830 ) Corporate expenses (36,218 ) (30,171 ) Foreign exchange losses (7,056 ) (37,860 ) Interest expense and financing costs (15,895 ) (16,763 ) Transaction and reorganization expenses (14,820 ) (13,054 ) Amortization of value of business acquired (13,104 ) (57,110 ) Amortization of intangible assets (3,003 ) (2,782 ) Income before income taxes and interest in income of equity method investments $ 107,796 $ 72,166 Net loss and loss expense ratio 56.4 % 60.7 % 58.5 % 55.4 % 57.9 % 56.7 % Acquisition cost ratio 21.2 % 24.7 % 23.0 % 15.1 % 24.2 % 19.6 % General and administrative expense ratio 19.0 % 5.6 % 15.4 % 17.6 % 6.3 % 14.5 % Combined ratio 96.6 % 91.0 % 96.9 % 88.1 % 88.4 % 90.8 % Total intangible assets $ 363,376 $ — $ 363,376 $ 506,747 $ — $ 506,747

INVESTMENTS (Tables)

INVESTMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
AMORTIZED COST/COST AND FAIR VALUES OF FIXED MATURITIES AND EQUITIES	The amortized cost and fair values of the Company's fixed maturities classified as available for sale were as follows: Amortized cost Gross unrealized gains Gross unrealized losses Fair value Non-credit OTTI in AOCI (5) At March 31, 2019 Fixed maturities U.S. government and agency $ 1,965,801 $ 12,365 $ (4,512 ) $ 1,973,654 $ — Non-U.S. government 488,056 6,448 (6,841 ) 487,663 — Corporate debt 4,809,079 62,910 (33,724 ) 4,838,265 — Agency RMBS (1) 1,708,610 14,430 (17,078 ) 1,705,962 — CMBS (2) 1,040,474 13,491 (1,825 ) 1,052,140 — Non-Agency RMBS 47,125 1,307 (1,021 ) 47,411 (819 ) ABS (3) 1,619,648 2,710 (9,348 ) 1,613,010 — Municipals (4) 155,414 1,481 (482 ) 156,413 — Total fixed maturities $ 11,834,207 $ 115,142 $ (74,831 ) $ 11,874,518 $ (819 ) At December 31, 2018 Fixed maturities U.S. government and agency $ 1,520,142 $ 4,232 $ (8,677 ) $ 1,515,697 $ — Non-U.S. government 507,550 1,586 (16,120 ) 493,016 — Corporate debt 4,990,279 15,086 (128,444 ) 4,876,921 — Agency RMBS (1) 1,666,684 6,508 (29,884 ) 1,643,308 — CMBS (2) 1,103,507 2,818 (13,795 ) 1,092,530 — Non-Agency RMBS 40,732 1,237 (1,282 ) 40,687 (857 ) ABS (3) 1,651,350 1,493 (15,240 ) 1,637,603 — Municipals (4) 136,068 914 (1,397 ) 135,585 — Total fixed maturities $ 11,616,312 $ 33,874 $ (214,839 ) $ 11,435,347 $ (857 ) (1) Residential mortgage-backed securities ("RMBS") originated by U.S. government-sponsored agencies. (2) Commercial mortgage-backed securities ("CMBS"). (3) Asset-backed securities ("ABS") include debt tranched securities collateralized primarily by auto loans, student loans, credit card receivables, collateralized debt obligations ("CDOs") and collateralized loan obligations ("CLOs"). (4) Municipals include bonds issued by states, municipalities and political subdivisions. (5) Represents the non-credit component of the other-than-temporary impairment ("OTTI") losses, adjusted for subsequent sales, maturities and redemptions. It does not include the change in fair value subsequent to the impairment measurement date.
EQUITY SECURITIES	The cost and fair values of the Company's equity securities were as follows: Cost Gross unrealized gains Gross unrealized losses Fair value At March 31, 2019 Equity securities Common stocks $ 693 $ 207 $ (315 ) $ 585 Exchange-traded funds 221,337 54,511 (4,240 ) 271,608 Bond mutual funds 154,463 — (7,793 ) 146,670 Total equity securities $ 376,493 $ 54,718 $ (12,348 ) $ 418,863 At December 31, 2018 Equity securities Common stocks $ 790 $ 112 $ (375 ) $ 527 Exchange-traded funds 213,420 33,498 (10,079 ) 236,839 Bond mutual funds 151,695 — (7,428 ) 144,267 Total equity securities $ 365,905 $ 33,610 $ (17,882 ) $ 381,633
CONTRACTUAL MATURITIES OF FIXED MATURITIES	Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. The contractual maturities of fixed maturities are shown below: Amortized cost Fair value % of Total fair value At March 31, 2019 Maturity Due in one year or less $ 408,537 $ 407,667 3.4 % Due after one year through five years 4,952,184 4,978,429 41.9 % Due after five years through ten years 1,710,102 1,719,806 14.5 % Due after ten years 347,527 350,093 2.9 % 7,418,350 7,455,995 62.7 % Agency RMBS 1,708,610 1,705,962 14.4 % CMBS 1,040,474 1,052,140 8.9 % Non-Agency RMBS 47,125 47,411 0.4 % ABS 1,619,648 1,613,010 13.6 % Total $ 11,834,207 $ 11,874,518 100.0 % At December 31, 2018 Maturity Due in one year or less $ 430,390 $ 426,142 3.7 % Due after one year through five years 4,751,064 4,691,263 41.0 % Due after five years through ten years 1,762,452 1,697,737 14.8 % Due after ten years 210,133 206,077 1.8 % 7,154,039 7,021,219 61.3 % Agency RMBS 1,666,684 1,643,308 14.4 % CMBS 1,103,507 1,092,530 9.6 % Non-Agency RMBS 40,732 40,687 0.4 % ABS 1,651,350 1,637,603 14.3 % Total $ 11,616,312 $ 11,435,347 100.0 %
FIXED MATURITIES AND EQUITIES IN AN UNREALIZED LOSS POSITION	The following table summarizes fixed maturities and equity securities in an unrealized loss position and the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position: 12 months or greater Less than 12 months Total Fair value Unrealized losses Fair value Unrealized losses Fair value Unrealized losses At March 31, 2019 (1) Fixed maturities U.S. government and agency $ 371,995 $ (4,194 ) $ 220,718 $ (318 ) $ 592,713 $ (4,512 ) Non-U.S. government 95,715 (3,368 ) 136,310 (3,473 ) 232,025 (6,841 ) Corporate debt 1,134,227 (20,122 ) 727,267 (13,602 ) 1,861,494 (33,724 ) Agency RMBS 849,681 (16,949 ) 26,971 (129 ) 876,652 (17,078 ) CMBS 244,188 (1,500 ) 85,473 (325 ) 329,661 (1,825 ) Non-Agency RMBS 9,360 (905 ) 12,111 (116 ) 21,471 (1,021 ) ABS 273,759 (2,757 ) 846,715 (6,591 ) 1,120,474 (9,348 ) Municipals 42,745 (452 ) 15,779 (30 ) 58,524 (482 ) Total fixed maturities $ 3,021,670 $ (50,247 ) $ 2,071,344 $ (24,584 ) $ 5,093,014 $ (74,831 ) At December 31, 2018 Fixed maturities U.S. government and agency $ 374,030 $ (7,659 ) $ 424,439 $ (1,018 ) $ 798,469 $ (8,677 ) Non-U.S. government 44,339 (2,004 ) 303,376 (14,116 ) 347,715 (16,120 ) Corporate debt 1,439,378 (58,915 ) 2,547,135 (69,529 ) 3,986,513 (128,444 ) Agency RMBS 940,645 (29,255 ) 117,181 (629 ) 1,057,826 (29,884 ) CMBS 455,582 (11,430 ) 353,802 (2,365 ) 809,384 (13,795 ) Non-Agency RMBS 9,494 (1,170 ) 11,432 (112 ) 20,926 (1,282 ) ABS 237,237 (2,755 ) 1,150,692 (12,485 ) 1,387,929 (15,240 ) Municipals 68,814 (1,373 ) 9,894 (24 ) 78,708 (1,397 ) Total fixed maturities $ 3,569,519 $ (114,561 ) $ 4,917,951 $ (100,278 ) $ 8,487,470 $ (214,839 )
MORTGAGE LOANS NET OF VALUATION ALLOWANCE	The following table provides details of the Company's mortgage loans held-for-investment: March 31, 2019 December 31, 2018 Carrying value % of Total Carrying value % of Total Mortgage Loans held-for-investment: Commercial $ 313,421 100 % $ 298,650 100 % Total Mortgage Loans held-for-investment $ 313,421 100 % $ 298,650 100 %
PORTFOLIO OF OTHER INVESTMENTS	The following tables provide a summary of the Company's other investments, together with additional information relating to the liquidity of each category: Fair value Redemption frequency (if currently eligible) Redemption notice period At March 31, 2019 Long/short equity funds $ 29,324 4 % Annually 60 days Multi-strategy funds 149,509 19 % Quarterly, Semi-annually 60-90 days Event-driven funds 5,914 1 % n/a n/a Direct lending funds 272,752 34 % n/a n/a Private equity funds 61,526 8 % n/a n/a Real estate funds 111,169 14 % n/a n/a CLO-Equities 18,022 1 % n/a n/a Other privately held investments 47,685 6 % n/a n/a Overseas deposits 99,430 13 % n/a n/a Total other investments $ 795,331 100 % At December 31, 2018 Long/short equity funds $ 26,779 3 % Annually 60 days Multi-strategy funds 153,883 20 % Quarterly, Semi-annually 60-95 days Event-driven funds 13,936 2 % Annually 45 days Direct lending funds 274,478 35 % n/a n/a Private equity funds 64,566 8 % n/a n/a Real estate funds 84,202 11 % n/a n/a CLO-Equities 21,271 2 % n/a n/a Other privately held investments 44,518 6 % n/a n/a Overseas deposits 104,154 13 % n/a n/a Total other investments $ 787,787 100 % n/a - not applicable
NET INVESTMENT INCOME	Net investment income was derived from the following sources: Three months ended March 31, 2019 2018 Fixed maturities $ 91,382 $ 83,958 Other investments 6,895 13,704 Equity securities 2,328 1,758 Mortgage loans 3,063 3,125 Cash and cash equivalents 5,801 4,153 Short-term investments 3,894 875 Gross investment income 113,363 107,573 Investment expenses (6,060 ) (6,574 ) Net investment income $ 107,303 $ 100,999
NET REALIZED INVESTMENT GAINS (LOSSES)	The following table provides an analysis of net investment gains (losses): Three months ended March 31, 2019 2018 Gross realized investment gains Fixed maturities and short-term investments $ 10,437 $ 31,628 Equity securities 1,445 17,557 Gross realized investment gains 11,882 49,185 Gross realized investment losses Fixed maturities and short-term investments (20,279 ) (43,535 ) Equity securities (93 ) (1,276 ) Gross realized investment losses (20,372 ) (44,811 ) Net OTTI recognized in net income (4,036 ) (414 ) Change in fair value of investment derivatives (1) (2,102 ) 2,023 Net unrealized gains (losses) on equity securities 27,395 (20,813 ) Net investment gains (losses) $ 12,767 $ (14,830 ) (1) Refer to Note 5 ' Derivative Instruments'.
OTTI RECOGNIZED IN EARNINGS BY ASSET CLASS	The following table summarizes the OTTI recognized in net income by asset class: Three months ended March 31, 2019 2018 Fixed maturities: Non-U.S. government $ 60 $ — Corporate debt 3,976 414 Total OTTI recognized in net income $ 4,036 $ 414
ROLL FORWARD OF CREDIT LOSSES FOR WHICH A PORTION OF OTTI RECOGNIZED IN AOCI	The following table provides a roll forward of the credit losses ("credit loss table") before income taxes, for which a component of the OTTI charge was recognized in AOCI: Three months ended March 31, 2019 2018 Balance at beginning of period $ 510 $ 1,494 Credit impairments recognized on securities not previously impaired — — Additional credit impairments recognized on securities previously impaired — — Change in timing of future cash flows on securities previously impaired — — Intent to sell of securities previously impaired — — Securities sold/redeemed/matured (38 ) (10 ) Balance at end of period $ 472 $ 1,484

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
FINANCIAL INSTRUMENTS MEASURED AT FAIR VALUE ON A RECURRING BASIS	The tables below present the financial instruments measured at fair value on a recurring basis for the periods indicated: Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Fair value based on NAV practical expedient Total fair value At March 31, 2019 Assets Fixed maturities U.S. government and agency $ 1,958,315 $ 15,339 $ — $ — $ 1,973,654 Non-U.S. government — 487,663 — — 487,663 Corporate debt — 4,797,140 41,125 — 4,838,265 Agency RMBS — 1,705,962 — — 1,705,962 CMBS — 1,040,995 11,145 — 1,052,140 Non-Agency RMBS — 47,411 — — 47,411 ABS — 1,600,967 12,043 — 1,613,010 Municipals — 156,413 — — 156,413 1,958,315 9,851,890 64,313 — 11,874,518 Equity securities Common stocks 585 — — — 585 Exchange-traded funds 271,608 — — — 271,608 Bond mutual funds — 146,670 — — 146,670 272,193 146,670 — — 418,863 Other investments Hedge funds (1) — — — 184,747 184,747 Direct lending funds — — — 272,752 272,752 Private equity funds — — — 61,526 61,526 Real estate funds — — — 111,169 111,169 Other privately held investments — — 47,685 — 47,685 CLO-Equities — — 18,022 — 18,022 Overseas deposits — 99,430 — — 99,430 — 99,430 65,707 630,194 795,331 Short-term investments — 41,853 — — 41,853 Other assets Derivative instruments (refer to Note 5) — 3,468 — — 3,468 Total Assets $ 2,230,508 $ 10,143,311 $ 130,020 $ 630,194 $ 13,134,033 Liabilities Derivative instruments (refer to Note 5) $ — $ 3,604 $ 10,233 $ — $ 13,837 Cash settled awards (refer to Note 8) — 7,878 — — 7,878 Total Liabilities $ — $ 11,482 $ 10,233 $ — $ 21,715 (1) Includes Long/short equity, Multi-strategy and Event-driven funds. Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Fair value based on NAV practical expedient Total fair value At December 31, 2018 Assets Fixed maturities U.S. government and agency $ 1,480,466 $ 35,231 $ — $ — $ 1,515,697 Non-U.S. government — 493,016 — — 493,016 Corporate debt — 4,827,909 49,012 — 4,876,921 Agency RMBS — 1,643,308 — — 1,643,308 CMBS — 1,073,396 19,134 — 1,092,530 Non-Agency RMBS — 40,687 — — 40,687 ABS — 1,619,070 18,533 — 1,637,603 Municipals — 135,585 — — 135,585 1,480,466 9,868,202 86,679 — 11,435,347 Equity securities Common stocks 527 — — — 527 Exchange-traded funds 236,839 — — — 236,839 Bond mutual funds — 144,267 — — 144,267 237,366 144,267 — — 381,633 Other investments Hedge funds (1) — — — 194,598 194,598 Direct lending funds — — — 274,478 274,478 Private equity funds — — — 64,566 64,566 Real estate funds — — — 84,202 84,202 Other privately held investments — — 44,518 — 44,518 CLO-Equities — — 21,271 — 21,271 Overseas deposits — 104,154 — — 104,154 — 104,154 65,789 617,844 787,787 Short-term investments — 144,040 — — 144,040 Other assets Derivative instruments (refer to Note 5) — 8,237 — — 8,237 Total Assets $ 1,717,832 $ 10,268,900 $ 152,468 $ 617,844 $ 12,757,044 Liabilities Derivative instruments (refer to Note 5) $ — $ 4,223 $ 10,299 $ — $ 14,522 Cash settled awards (refer to Note 8) — 20,648 — — 20,648 Total Liabilities $ — $ 24,871 $ 10,299 $ — $ 35,170 (1) Includes Long/short equity, Multi-strategy and Event-driven funds.
LEVEL 3 FAIR VALUE MEASUREMENT INPUTS	The following table quantifies the significant unobservable inputs used in estimating fair values at March 31, 2019 of investments classified as Level 3 in the fair value hierarchy. Fair value Valuation technique Unobservable input Range Weighted average Other investments - CLO-Equities $ 18,022 Discounted cash flow Default rates 3.0% 3.0% Loss severity rate 35.0% 35.0% Collateral spreads 3.0% 3.0% Estimated maturity dates 7 years 7 years Other investments - Other privately held investments $ 47,685 Discounted cash flow Discount rate 3.0% - 8.0% 6.5% Derivatives - Other underwriting-related derivatives $ (10,233 ) Discounted cash flow Discount rate 2.3% 2.3% Note: Fixed maturities and insurance-linked securities that are classified as Level 3 are excluded from the above table as these securities are priced using broker-dealer quotes.
CHANGES IN LEVEL 3 FINANCIAL INSTRUMENTS MEASURED AT FAIR VALUE ON A RECURRING BASIS, ASSETS	The following tables present changes in Level 3 for financial instruments measured at fair value on a recurring basis for the periods indicated: Opening balance Transfers into Level 3 Transfers out of Level 3 Included in net income (1) Included in OCI (2) Purchases Sales Settlements/ distributions Closing balance Change in unrealized investment gains/(losses) (3) Three months ended March 31, 2019 Fixed maturities Corporate debt $ 49,012 $ — $ — $ (696 ) $ 624 $ — $ (5,547 ) $ (2,268 ) $ 41,125 $ — CMBS 19,134 — (4,767 ) — 143 — — (3,365 ) 11,145 — ABS 18,533 — (16,402 ) — 162 9,750 — — 12,043 — 86,679 — (21,169 ) (696 ) 929 9,750 (5,547 ) (5,633 ) 64,313 — Other investments Other privately held investments 44,518 — — 667 — 2,500 — — 47,685 667 CLO - Equities 21,271 — — 415 — — — (3,664 ) 18,022 415 65,789 — — 1,082 — 2,500 — (3,664 ) 65,707 1,082 Other assets Insurance-linked securities — — — — — — — — — — — — — — — — — — — — Total assets $ 152,468 $ — $ (21,169 ) $ 386 $ 929 $ 12,250 $ (5,547 ) $ (9,297 ) $ 130,020 $ 1,082 Other liabilities Derivative instruments $ 10,299 $ — $ — $ (66 ) $ — $ — $ — $ — $ 10,233 $ (66 ) Total liabilities $ 10,299 $ — $ — $ (66 ) $ — $ — $ — $ — $ 10,233 $ (66 ) Opening balance Transfers into Level 3 Transfers out of Level 3 Included in net income (1) Included in OCI (2) Purchases Sales Settlements/ distributions Closing balance Change in unrealized investment gains/(losses) (3) Three months ended March 31, 2018 Fixed maturities Corporate debt $ 52,897 $ — $ (4,279 ) $ (118 ) $ 1,403 $ — $ (2,536 ) $ (3,896 ) $ 43,471 $ — CMBS — — — — — — — — — — ABS — — — — — — — — — — 52,897 — (4,279 ) (118 ) 1,403 — (2,536 ) (3,896 ) 43,471 — Other investments Other privately held investments 46,430 — — 746 — 3,111 (1,500 ) — 48,787 746 CLO - Equities 31,413 — — 1,616 — — — (4,473 ) 28,556 1,616 77,843 — — 2,362 — 3,111 (1,500 ) (4,473 ) 77,343 2,362 Other assets Insurance-linked securities 25,090 — — (90 ) — — — — 25,000 (90 ) 25,090 — — (90 ) — — — — 25,000 (90 ) Total assets $ 155,830 $ — $ (4,279 ) $ 2,154 $ 1,403 $ 3,111 $ (4,036 ) $ (8,369 ) $ 145,814 $ 2,272 Other liabilities Derivative instruments $ 11,510 $ — $ — $ (568 ) $ — $ — $ — $ — $ 10,942 $ (568 ) Total liabilities $ 11,510 $ — $ — $ (568 ) $ — $ — $ — $ — $ 10,942 $ (568 ) (1) Realized investment gains (losses) on fixed maturities, and realized and unrealized gains (losses) on other assets and other liabilities included in net income are included in net investment gains (losses). Realized and unrealized gains (losses) on other investments included in net income are included in net investment income. (2) Unrealized investment gains (losses) on fixed maturities are included in other comprehensive income ("OCI"). (3) Change in unrealized investment gains (losses) relating to assets held at the reporting date.
CHANGES IN LEVEL 3 FINANCIAL INSTRUMENTS MEASURED AT FAIR VALUE ON A RECURRING BASIS, LIABILITIES	The following tables present changes in Level 3 for financial instruments measured at fair value on a recurring basis for the periods indicated: Opening balance Transfers into Level 3 Transfers out of Level 3 Included in net income (1) Included in OCI (2) Purchases Sales Settlements/ distributions Closing balance Change in unrealized investment gains/(losses) (3) Three months ended March 31, 2019 Fixed maturities Corporate debt $ 49,012 $ — $ — $ (696 ) $ 624 $ — $ (5,547 ) $ (2,268 ) $ 41,125 $ — CMBS 19,134 — (4,767 ) — 143 — — (3,365 ) 11,145 — ABS 18,533 — (16,402 ) — 162 9,750 — — 12,043 — 86,679 — (21,169 ) (696 ) 929 9,750 (5,547 ) (5,633 ) 64,313 — Other investments Other privately held investments 44,518 — — 667 — 2,500 — — 47,685 667 CLO - Equities 21,271 — — 415 — — — (3,664 ) 18,022 415 65,789 — — 1,082 — 2,500 — (3,664 ) 65,707 1,082 Other assets Insurance-linked securities — — — — — — — — — — — — — — — — — — — — Total assets $ 152,468 $ — $ (21,169 ) $ 386 $ 929 $ 12,250 $ (5,547 ) $ (9,297 ) $ 130,020 $ 1,082 Other liabilities Derivative instruments $ 10,299 $ — $ — $ (66 ) $ — $ — $ — $ — $ 10,233 $ (66 ) Total liabilities $ 10,299 $ — $ — $ (66 ) $ — $ — $ — $ — $ 10,233 $ (66 ) Opening balance Transfers into Level 3 Transfers out of Level 3 Included in net income (1) Included in OCI (2) Purchases Sales Settlements/ distributions Closing balance Change in unrealized investment gains/(losses) (3) Three months ended March 31, 2018 Fixed maturities Corporate debt $ 52,897 $ — $ (4,279 ) $ (118 ) $ 1,403 $ — $ (2,536 ) $ (3,896 ) $ 43,471 $ — CMBS — — — — — — — — — — ABS — — — — — — — — — — 52,897 — (4,279 ) (118 ) 1,403 — (2,536 ) (3,896 ) 43,471 — Other investments Other privately held investments 46,430 — — 746 — 3,111 (1,500 ) — 48,787 746 CLO - Equities 31,413 — — 1,616 — — — (4,473 ) 28,556 1,616 77,843 — — 2,362 — 3,111 (1,500 ) (4,473 ) 77,343 2,362 Other assets Insurance-linked securities 25,090 — — (90 ) — — — — 25,000 (90 ) 25,090 — — (90 ) — — — — 25,000 (90 ) Total assets $ 155,830 $ — $ (4,279 ) $ 2,154 $ 1,403 $ 3,111 $ (4,036 ) $ (8,369 ) $ 145,814 $ 2,272 Other liabilities Derivative instruments $ 11,510 $ — $ — $ (568 ) $ — $ — $ — $ — $ 10,942 $ (568 ) Total liabilities $ 11,510 $ — $ — $ (568 ) $ — $ — $ — $ — $ 10,942 $ (568 ) (1) Realized investment gains (losses) on fixed maturities, and realized and unrealized gains (losses) on other assets and other liabilities included in net income are included in net investment gains (losses). Realized and unrealized gains (losses) on other investments included in net income are included in net investment income. (2) Unrealized investment gains (losses) on fixed maturities are included in other comprehensive income ("OCI"). (3) Change in unrealized investment gains (losses) relating to assets held at the reporting date.

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
LOCATION AND AMOUNTS OF DERIVATIVE FAIR VALUES ON THE CONSOLIDATED BALANCE SHEET	The balance sheet classifications of derivatives recorded at fair value are shown in the following table. March 31, 2019 December 31, 2018 Derivative notional amount Derivative asset fair value (1) Derivative liability fair value (1) Derivative notional amount Derivative asset fair value (1) Derivative liability fair value (1) Relating to investment portfolio: Foreign exchange forward contracts $ 172,306 $ 818 $ 284 $ 79,336 $ 262 $ 531 Interest rate swaps 85,000 984 — 150,000 — 1,116 Relating to underwriting portfolio: Foreign exchange forward contracts 543,174 1,666 3,320 737,419 7,975 2,576 Other underwriting-related contracts 85,000 — 10,233 85,000 — 10,299 Total derivatives $ 3,468 $ 13,837 $ 8,237 $ 14,522 (1) Asset and liability derivatives are classified within other assets and other liabilities in the consolidated balance sheets.
RECONCILIATION OF GROSS DERIVATIVE ASSETS TO NET AMOUNTS PRESENTED IN BALANCE SHEETS	A reconciliation of gross derivative assets and liabilities to the net amounts presented in the consolidated balance sheets, with the difference being attributable to the impact of master netting agreements, is shown in the following table. March 31, 2019 December 31, 2018 Gross amounts Gross amounts offset Net amounts (1) Gross amounts Gross amounts offset Net amounts (1) Derivative assets $ 6,115 $ (2,647 ) $ 3,468 $ 11,967 $ (3,730 ) $ 8,237 Derivative liabilities $ 16,484 $ (2,647 ) $ 13,837 $ 18,252 $ (3,730 ) $ 14,522 (1) Net asset and liability derivatives are classified within other assets and other liabilities in the consolidated balance sheets.
RECONCILIATION OF GROSS DERIVATIVE LIABILITIES TO NET AMOUNTS PRESENTED IN BALANCE SHEETS	A reconciliation of gross derivative assets and liabilities to the net amounts presented in the consolidated balance sheets, with the difference being attributable to the impact of master netting agreements, is shown in the following table. March 31, 2019 December 31, 2018 Gross amounts Gross amounts offset Net amounts (1) Gross amounts Gross amounts offset Net amounts (1) Derivative assets $ 6,115 $ (2,647 ) $ 3,468 $ 11,967 $ (3,730 ) $ 8,237 Derivative liabilities $ 16,484 $ (2,647 ) $ 13,837 $ 18,252 $ (3,730 ) $ 14,522 (1) Net asset and liability derivatives are classified within other assets and other liabilities in the consolidated balance sheets.
TOTAL UNREALIZED AND REALIZED GAINS (LOSSES) ON DERIVATIVES NOT DESIGNATED AS HEDGES RECORDED IN EARNINGS	The total unrealized and realized gains (losses) recognized in net income for derivatives not designated as hedges are shown in the following table: Location of gain (loss) recognized in net income Three months ended March 31, 2019 2018 Relating to investment portfolio: Foreign exchange forward contracts Net investment gains (losses) $ 752 $ (1,191 ) Interest rate swaps Net investment gains (losses) (2,854 ) 3,214 Relating to underwriting portfolio: Foreign exchange forward contracts Foreign exchange gains (losses) (10,517 ) 7,768 Other underwriting-related contracts Other insurance related income (losses) 347 901 Total $ (12,272 ) $ 10,692

RESERVE FOR LOSSES AND LOSS E_2

RESERVE FOR LOSSES AND LOSS EXPENSES (Tables)	3 Months Ended
	Mar. 31, 2019
Insurance Loss Reserves [Abstract]
RECONCILIATION OF BEGINNING AND ENDING GROSS RESERVE FOR LOSSES AND LOSS EXPENSES AND NET RESERVE FOR UNPAID LOSSES AND LOSS EXPENSES	The following table presents a reconciliation of the Company's beginning and ending gross reserve for losses and loss expenses and net reserve for unpaid losses and loss expenses for the periods indicated: Three months ended March 31, 2019 2018 Gross reserve for losses and loss expenses, beginning of period $ 12,280,769 $ 12,997,553 Less reinsurance recoverable on unpaid losses, beginning of period (3,501,669 ) (3,159,514 ) Net reserve for unpaid losses and loss expenses, beginning of period 8,779,100 9,838,039 Net incurred losses and loss expenses related to: Current year 678,700 715,652 Prior years (14,672 ) (54,307 ) 664,028 661,345 Net paid losses and loss expenses related to: Current year (37,600 ) (48,814 ) Prior years (691,558 ) (675,393 ) (729,158 ) (724,207 ) Foreign exchange and other 6,460 (726,781 ) Net reserve for unpaid losses and loss expenses, end of period 8,720,430 9,048,396 Reinsurance recoverable on unpaid losses, end of period 3,555,341 2,986,247 Gross reserve for losses and loss expenses, end of period $ 12,275,771 $ 12,034,643
NET PRIOR YEAR RESERVE DEVELOPMENT BY SEGMENT	The Company's net favorable prior year reserve development arises from changes to loss and loss expense estimates related to loss events that occurred in previous calendar years. The following table presents net prior year reserve development by segment: Three months ended March 31, 2019 2018 Insurance $ 6,913 $ 22,775 Reinsurance 7,759 31,532 Total $ 14,672 $ 54,307
SCHEDULE OF THE LINE OF BUSINESS CATEGORIES AND THE EXPECTED CLAIM TAILS	The following tables map the Company's line of business to reserve classes and the expected claim tails: Insurance segment Reserve class and tail Property and other Marine Aviation Credit and political risk Professional lines Liability Short Short Short/Medium Medium Medium Long Reported lines of business Property X Marine X Terrorism X Aviation X Credit and political risk X Professional lines X Liability X Accident and health X Discontinued lines - Novae X X X Reinsurance segment Reserve class and tail Property and other Credit and surety Professional lines Motor Liability Short Medium Medium Long Long Reported lines of business Catastrophe X Property X Credit and surety X Professional lines X Motor X Liability X Engineering X Agriculture X Marine and other X Accident and health X Discontinued lines - Novae X X X

EARNINGS PER COMMON SHARE (Tabl

EARNINGS PER COMMON SHARE (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
BASIC AND DILUTED EARNINGS PER COMMON SHARE	The following table presents a comparison of earnings per common share and earnings per diluted common share: Three months ended March 31, 2019 2018 Earnings per common share Net income $ 108,781 $ 73,202 Less: Preferred share dividends 10,656 10,656 Net income available to common shareholders 98,125 62,546 Weighted average common shares outstanding 83,725 83,322 Earnings per common share $ 1.17 $ 0.75 Earnings per diluted common share Net income available to common shareholders $ 98,125 $ 62,546 Weighted average common shares outstanding 83,725 83,322 Share-based compensation plans 547 399 Weighted average diluted common shares outstanding 84,272 83,721 Earnings per diluted common share $ 1.16 $ 0.75 Weighted average anti-dilutive shares excluded from the dilutive computation 601 810

SHARE-BASED COMPENSATION (Table

SHARE-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
RECONCILIATIONS OF BEGINNING AND ENDING BALANCE OF NONVESTED RESTRICTED STOCK (INCLUDING RSUS) TO BE SETTLED IN SHARES AND CASH	The following table provides an activity summary of the Company's cash-settled restricted stock units for the three months ended March 31, 2019 : Cash-Settled Performance Vesting Restricted Stock Units Cash-Settled Service Based Restricted Stock Units Number of restricted stock units Number of restricted stock units Nonvested restricted stock units - beginning of period 27 932 Granted — 349 Vested (12 ) (320 ) Forfeited — (35 ) Nonvested restricted stock units - end of period 15 926 The following table provides an activity summary of the Company's share-settled restricted stock units for the three months ended March 31, 2019 : Share-Settled Performance Vesting Restricted Stock Units Share-Settled Service Based Restricted Stock Units Number of restricted stock units Weighted average grant date fair value (1) Number of restricted stock units Weighted average grant date fair value (1) Nonvested restricted stock units - beginning of period 232 $ 54.54 1,411 $ 54.12 Granted 127 54.70 508 54.67 Vested (61 ) 53.82 (445 ) 54.04 Forfeited — — (74 ) 54.84 Nonvested restricted stock units - end of period 298 $ 54.76 1,400 $ 54.31 (1) Fair value is based on the closing price of the Company's common shares on the grant date.

SHAREHOLDERS' EQUITY (Tables)

SHAREHOLDERS' EQUITY (Tables)	3 Months Ended
	Mar. 31, 2019
Stockholders' Equity Note [Abstract]
COMMON SHARES ISSUED AND OUTSTANDING	The following table presents changes in common shares issued and outstanding: Three months ended March 31, 2019 2018 Shares issued, balance at beginning of period 176,580 176,580 Shares issued — — Total shares issued at end of period 176,580 176,580 Treasury shares, balance at beginning of period (92,994 ) (93,419 ) Shares repurchased (157 ) (149 ) Shares reissued 505 506 Total treasury shares at end of period (92,646 ) (93,062 ) Total shares outstanding 83,934 83,518
SHARE REPURCHASES	The following table presents common share repurchased from shares held in Treasury: Three months ended March 31, 2019 2018 In the open market: Total shares — — Total cost $ — $ — Average price per share (1) $ — $ — From employees: (2) Total shares 157 149 Total cost $ 9,003 $ 7,163 Average price per share (1) $ 57.17 $ 48.08 Total shares repurchased: Total shares 157 149 Total cost $ 9,003 $ 7,163 Average price per share (1) $ 57.17 $ 48.08 (1) Calculated using whole numbers. (2) Shares are repurchased from employees to satisfy withholding tax liabilities related to the vesting of share-settled restricted stock units.

LEASES (Tables)

LEASES (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Summary of lease expense and related cash flows	The following table summarizes the amounts related to the Company’s total lease expense and the cash flows arising from lease transactions. Three months ended March 31, 2019 Lease cost: Operating lease expense $ 6,930 Short-term lease expense (1) 646 Sublease income (2) (542 ) Total lease expense $ 7,034 Other information: Operating cash outflows from operating leases $ 6,536 Right-of-use assets obtained in exchange for new operating lease liabilities $ — Weighted-average remaining lease term - operating leases (3) 8.8 years Weighted-average discount rate - operating lease (4) 4.7 % (1) Short-term lease expense is recognized on a straight-line basis over the lease term. (2) Sublease income largely relates to office property in London, England. (3) Weighted-average remaining lease term was calculated on the basis of the remaining lease term and the lease liability balance for each lease at the reporting date. (4) Weighted-average discount was calculated on the basis of the discount rate for the lease that was used to calculate the lease liability balance for each lease at the reporting date and the remaining balance of the lease payments for each lease at the reporting date.
Maturity schedule and minimum lease payments	At March 31, 2019 , the scheduled maturity of the Company's operating lease liabilities are expected to be as follows: Expected Cash Flows Remainder of 2019 $ 19,818 2020 22,545 2021 22,451 2022 23,165 2023 19,042 Later years 72,536 Discount (35,259 ) Total discounted operating lease liabilities $ 144,298 At December 31, 2018, the Company's future minimum lease payments were expected to be as follows: Year ended December 31, 2019 $ 28,240 2020 25,331 2021 27,025 2022 28,012 2023 23,801 Later years 118,497 Total future minimum lease payments $ 250,906 For the three months ended March 31, 2018 , the total lease expense was $7 million .

OTHER COMPREHENSIVE INCOME (L_2

OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
TAX EFFECTS ALLOCATED TO EACH COMPONENT OF OTHER COMPREHENSIVE INCOME	The following table presents the tax effects allocated to each component of other comprehensive income (loss): 2019 2018 Before tax amount Tax (expense) benefit Net of tax amount Before tax amount Tax (expense) benefit Net of Tax Amount Three months ended March 31, Available for sale investments: Unrealized investment gains (losses) arising during the period $ 206,806 $ (16,633 ) $ 190,173 $ (105,675 ) $ (6,516 ) $ (112,191 ) Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income 13,874 (504 ) 13,370 (4,112 ) 4,897 785 Unrealized investment gains (losses) arising during the period, net of reclassification adjustment 220,680 (17,137 ) 203,543 (109,787 ) (1,619 ) (111,406 ) Non-credit portion of OTTI losses — — — — — — Foreign currency translation adjustment 2,662 — 2,662 1,270 — 1,270 Total other comprehensive income (loss), net of tax $ 223,342 $ (17,137 ) $ 206,205 $ (108,517 ) $ (1,619 ) $ (110,136 )
RECLASSIFICATIONS OUT OF AOCI INTO NET INCOME AVAILABLE TO COMMON SHAREHOLDERS	The following table presents reclassifications from accumulated other comprehensive income ("AOCI") to net income available to common shareholders: Amount reclassified from AOCI (1) Details about AOCI Components Consolidated statement of operations line item that includes reclassification Three months ended March 31, 2019 2018 Unrealized investment gains (losses) on available for sale investments Other realized investment gains (losses) $ (9,838 ) $ 4,526 OTTI losses (4,036 ) (414 ) Total before tax (13,874 ) 4,112 Income tax (expense) benefit 504 (4,897 ) Net of tax $ (13,370 ) $ (785 ) (1) Amounts in parentheses are debits to net income (loss) available (attributable) to common shareholders.

BASIS OF PRESENTATION AND SIG_3

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Operating lease right-of-use assets	$ 143,887	$ 0
Short-term lease expense	646
Operating lease liabilities	$ 144,298	$ 0

SEGMENT INFORMATION (Details)

SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)reportable_segment	Mar. 31, 2018USD ($)
Segment Information [Line Items]
Number of reportable segments | reportable_segment	2
Net premiums earned	$ 1,134,212	$ 1,167,402
Other insurance related income (losses)	6,929	6,606
Net losses and loss expenses	(664,028)	(661,345)
Acquisition costs	(260,418)	(229,260)
Expenses	(175,091)	(169,837)
Net investment income	107,303	100,999
Net investment gains (losses)	12,767	(14,830)
Operating lease expense	7,034	7,000
Foreign exchange losses	(7,056)	(37,860)
Interest expense and financing costs	(15,895)	(16,763)
Transaction and reorganization expenses	(14,820)	(13,054)
Amortization of value of business acquired	(13,104)	(57,110)
Amortization of intangible assets	(3,003)	(2,782)
Income before income taxes and interest in income of equity method investments	$ 107,796	$ 72,166
Net loss and loss expense ratio	58.50%	56.70%
Acquisition cost ratio	23.00%	19.60%
General and administrative expense ratio	15.40%	14.50%
Combined ratio	96.90%	90.80%
Total intangible assets	$ 363,376	$ 506,747
Operating Segments
Segment Information [Line Items]
Gross premiums written	2,583,226	2,662,795
Net premiums written	1,777,059	1,985,871
Net premiums earned	1,134,212	1,167,402
Other insurance related income (losses)	6,929	6,606
Net losses and loss expenses	(664,028)	(661,345)
Acquisition costs	(260,418)	(229,260)
Expenses	(138,873)	(139,666)
Underwriting income	77,822	143,737
Operating Segments | Insurance
Segment Information [Line Items]
Gross premiums written	851,096	880,848
Net premiums written	529,239	547,893
Net premiums earned	556,762	580,059
Other insurance related income (losses)	1,742	620
Net losses and loss expenses	(313,776)	(321,538)
Acquisition costs	(117,775)	(87,329)
Expenses	(106,034)	(102,370)
Underwriting income	$ 20,919	$ 69,442
Net loss and loss expense ratio	56.40%	55.40%
Acquisition cost ratio	21.20%	15.10%
General and administrative expense ratio	19.00%	17.60%
Combined ratio	96.60%	88.10%
Total intangible assets	$ 363,376	$ 506,747
Operating Segments | Reinsurance
Segment Information [Line Items]
Gross premiums written	1,732,130	1,781,947
Net premiums written	1,247,820	1,437,978
Net premiums earned	577,450	587,343
Other insurance related income (losses)	5,187	5,986
Net losses and loss expenses	(350,252)	(339,807)
Acquisition costs	(142,643)	(141,931)
Expenses	(32,839)	(37,296)
Underwriting income	$ 56,903	$ 74,295
Net loss and loss expense ratio	60.70%	57.90%
Acquisition cost ratio	24.70%	24.20%
General and administrative expense ratio	5.60%	6.30%
Combined ratio	91.00%	88.40%
Total intangible assets	$ 0	$ 0
Corporate, Non-Segment
Segment Information [Line Items]
Expenses	(36,218)	(30,171)
Significant Reconciling Items
Segment Information [Line Items]
Net investment income	107,303	100,999
Net investment gains (losses)	12,767	(14,830)
Foreign exchange losses	(7,056)	(37,860)
Interest expense and financing costs	(15,895)	(16,763)
Transaction and reorganization expenses	(14,820)	(13,054)
Amortization of value of business acquired	(13,104)	(57,110)
Amortization of intangible assets	$ (3,003)	$ (2,782)

INVESTMENTS (Fixed Maturities)

INVESTMENTS (Fixed Maturities) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fixed maturities
Amortized cost	$ 11,834,207	$ 11,616,312
Gross unrealized gains	115,142	33,874
Gross unrealized losses	(74,831)	(214,839)
Fair value	11,874,518	11,435,347
Non-credit OTTI in AOCI	(819)	(857)
U.S. government and agency
Fixed maturities
Amortized cost	1,965,801	1,520,142
Gross unrealized gains	12,365	4,232
Gross unrealized losses	(4,512)	(8,677)
Fair value	1,973,654	1,515,697
Non-credit OTTI in AOCI	0	0
Non-U.S. government
Fixed maturities
Amortized cost	488,056	507,550
Gross unrealized gains	6,448	1,586
Gross unrealized losses	(6,841)	(16,120)
Fair value	487,663	493,016
Non-credit OTTI in AOCI	0	0
Corporate debt
Fixed maturities
Amortized cost	4,809,079	4,990,279
Gross unrealized gains	62,910	15,086
Gross unrealized losses	(33,724)	(128,444)
Fair value	4,838,265	4,876,921
Non-credit OTTI in AOCI	0	0
Agency RMBS
Fixed maturities
Amortized cost	1,708,610	1,666,684
Gross unrealized gains	14,430	6,508
Gross unrealized losses	(17,078)	(29,884)
Fair value	1,705,962	1,643,308
Non-credit OTTI in AOCI	0	0
CMBS
Fixed maturities
Amortized cost	1,040,474	1,103,507
Gross unrealized gains	13,491	2,818
Gross unrealized losses	(1,825)	(13,795)
Fair value	1,052,140	1,092,530
Non-credit OTTI in AOCI	0	0
Non-Agency RMBS
Fixed maturities
Amortized cost	47,125	40,732
Gross unrealized gains	1,307	1,237
Gross unrealized losses	(1,021)	(1,282)
Fair value	47,411	40,687
Non-credit OTTI in AOCI	(819)	(857)
ABS
Fixed maturities
Amortized cost	1,619,648	1,651,350
Gross unrealized gains	2,710	1,493
Gross unrealized losses	(9,348)	(15,240)
Fair value	1,613,010	1,637,603
Non-credit OTTI in AOCI	0	0
Municipals
Fixed maturities
Amortized cost	155,414	136,068
Gross unrealized gains	1,481	914
Gross unrealized losses	(482)	(1,397)
Fair value	156,413	135,585
Non-credit OTTI in AOCI	$ 0	$ 0

INVESTMENTS (Equity Securities)

INVESTMENTS (Equity Securities) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Investment [Line Items]
Cost	$ 376,493	$ 365,905
Gross unrealized gains	54,718	33,610
Gross unrealized losses	(12,348)	(17,882)
Fair value	418,863	381,633
Common stocks
Investment [Line Items]
Cost	693	790
Gross unrealized gains	207	112
Gross unrealized losses	(315)	(375)
Fair value	585	527
Exchange-traded funds
Investment [Line Items]
Cost	221,337	213,420
Gross unrealized gains	54,511	33,498
Gross unrealized losses	(4,240)	(10,079)
Fair value	271,608	236,839
Bond mutual funds
Investment [Line Items]
Cost	154,463	151,695
Gross unrealized gains	0	0
Gross unrealized losses	(7,793)	(7,428)
Fair value	$ 146,670	$ 144,267

INVESTMENTS (Contractual Maturi

INVESTMENTS (Contractual Maturities) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Due in one year or less (amortized cost)	$ 408,537	$ 430,390
Due after one year through five years (amortized cost)	4,952,184	4,751,064
Due after five years through ten years (amortized cost)	1,710,102	1,762,452
Due after ten years (amortized cost)	347,527	210,133
Total fixed maturities with a single maturity date (amortized cost)	7,418,350	7,154,039
Amortized cost	11,834,207	11,616,312
Due in one year or less (fair value)	407,667	426,142
Due after one year through five years (fair value)	4,978,429	4,691,263
Due after five years through ten years (fair value)	1,719,806	1,697,737
Due after ten years (fair value)	350,093	206,077
Total fixed maturities with a single maturity date (fair value)	7,455,995	7,021,219
Fair Value	$ 11,874,518	$ 11,435,347
Due in one year or less (% of total fair value)	3.40%	3.70%
Due after one year through five years (% of total fair value)	41.90%	41.00%
Due after five years through ten years (% of total fair value)	14.50%	14.80%
Due after ten years (% of total fair value)	2.90%	1.80%
Fixed maturities with a single maturity date (% of total fair value)	62.70%	61.30%
Total	100.00%	100.00%
Agency RMBS
Schedule Of Available For Sale Securities [Line Items]
Fixed maturities without a single maturity date (amortized cost)	$ 1,708,610	$ 1,666,684
Amortized cost	1,708,610	1,666,684
Fixed maturities without a single maturity date (fair value)	1,705,962	1,643,308
Fair Value	$ 1,705,962	$ 1,643,308
Fixed maturities without a single maturity date (% of total fair value)	14.40%	14.40%
CMBS
Schedule Of Available For Sale Securities [Line Items]
Fixed maturities without a single maturity date (amortized cost)	$ 1,040,474	$ 1,103,507
Amortized cost	1,040,474	1,103,507
Fixed maturities without a single maturity date (fair value)	1,052,140	1,092,530
Fair Value	$ 1,052,140	$ 1,092,530
Fixed maturities without a single maturity date (% of total fair value)	8.90%	9.60%
Non-Agency RMBS
Schedule Of Available For Sale Securities [Line Items]
Fixed maturities without a single maturity date (amortized cost)	$ 47,125	$ 40,732
Amortized cost	47,125	40,732
Fixed maturities without a single maturity date (fair value)	47,411	40,687
Fair Value	$ 47,411	$ 40,687
Fixed maturities without a single maturity date (% of total fair value)	0.40%	0.40%
ABS
Schedule Of Available For Sale Securities [Line Items]
Fixed maturities without a single maturity date (amortized cost)	$ 1,619,648	$ 1,651,350
Amortized cost	1,619,648	1,651,350
Fixed maturities without a single maturity date (fair value)	1,613,010	1,637,603
Fair Value	$ 1,613,010	$ 1,637,603
Fixed maturities without a single maturity date (% of total fair value)	13.60%	14.30%

INVESTMENTS (Gross Unrealized L

INVESTMENTS (Gross Unrealized Losses) (Details) $ in Thousands	Mar. 31, 2019USD ($)security	Dec. 31, 2018USD ($)security
U.S. government and agency
Fixed maturities
Fair Value - 12 months or greater	$ 371,995	$ 374,030
Unrealized Losses - 12 months or greater	(4,194)	(7,659)
Fair Value - Less than 12 months	220,718	424,439
Unrealized Losses - Less than 12 months	(318)	(1,018)
Total Fair Value of Securities in Unrealized Loss Position	592,713	798,469
Total Unrealized Losses	(4,512)	(8,677)
Non-U.S. government
Fixed maturities
Fair Value - 12 months or greater	95,715	44,339
Unrealized Losses - 12 months or greater	(3,368)	(2,004)
Fair Value - Less than 12 months	136,310	303,376
Unrealized Losses - Less than 12 months	(3,473)	(14,116)
Total Fair Value of Securities in Unrealized Loss Position	232,025	347,715
Total Unrealized Losses	(6,841)	(16,120)
Corporate debt
Fixed maturities
Fair Value - 12 months or greater	1,134,227	1,439,378
Unrealized Losses - 12 months or greater	(20,122)	(58,915)
Fair Value - Less than 12 months	727,267	2,547,135
Unrealized Losses - Less than 12 months	(13,602)	(69,529)
Total Fair Value of Securities in Unrealized Loss Position	1,861,494	3,986,513
Total Unrealized Losses	(33,724)	(128,444)
Agency RMBS
Fixed maturities
Fair Value - 12 months or greater	849,681	940,645
Unrealized Losses - 12 months or greater	(16,949)	(29,255)
Fair Value - Less than 12 months	26,971	117,181
Unrealized Losses - Less than 12 months	(129)	(629)
Total Fair Value of Securities in Unrealized Loss Position	876,652	1,057,826
Total Unrealized Losses	(17,078)	(29,884)
CMBS
Fixed maturities
Fair Value - 12 months or greater	244,188	455,582
Unrealized Losses - 12 months or greater	(1,500)	(11,430)
Fair Value - Less than 12 months	85,473	353,802
Unrealized Losses - Less than 12 months	(325)	(2,365)
Total Fair Value of Securities in Unrealized Loss Position	329,661	809,384
Total Unrealized Losses	(1,825)	(13,795)
Non-Agency RMBS
Fixed maturities
Fair Value - 12 months or greater	9,360	9,494
Unrealized Losses - 12 months or greater	(905)	(1,170)
Fair Value - Less than 12 months	12,111	11,432
Unrealized Losses - Less than 12 months	(116)	(112)
Total Fair Value of Securities in Unrealized Loss Position	21,471	20,926
Total Unrealized Losses	(1,021)	(1,282)
ABS
Fixed maturities
Fair Value - 12 months or greater	273,759	237,237
Unrealized Losses - 12 months or greater	(2,757)	(2,755)
Fair Value - Less than 12 months	846,715	1,150,692
Unrealized Losses - Less than 12 months	(6,591)	(12,485)
Total Fair Value of Securities in Unrealized Loss Position	1,120,474	1,387,929
Total Unrealized Losses	(9,348)	(15,240)
Municipals
Fixed maturities
Fair Value - 12 months or greater	42,745	68,814
Unrealized Losses - 12 months or greater	(452)	(1,373)
Fair Value - Less than 12 months	15,779	9,894
Unrealized Losses - Less than 12 months	(30)	(24)
Total Fair Value of Securities in Unrealized Loss Position	58,524	78,708
Total Unrealized Losses	(482)	(1,397)
Fixed maturities
Fixed maturities
Fair Value - 12 months or greater	3,021,670	3,569,519
Unrealized Losses - 12 months or greater	(50,247)	(114,561)
Fair Value - Less than 12 months	2,071,344	4,917,951
Unrealized Losses - Less than 12 months	(24,584)	(100,278)
Total Fair Value of Securities in Unrealized Loss Position	5,093,014	8,487,470
Total Unrealized Losses	$ (74,831)	$ (214,839)
Number of available for sale securities in unrealized loss positions | security	2,521	3,599
Number of available for sale securities in unrealized loss positions for 12 months or greater | security	1,553	1,656
Fixed maturities | Below Investment Grade or Not Rated
Fixed maturities
Total Unrealized Losses	$ (15,000)	$ (49,000)

INVESTMENTS (Mortgage Loans) (D

INVESTMENTS (Mortgage Loans) (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Mortgage Loans held-for-investment, net [Abstract]
Commercial	$ 313,421,000	$ 298,650,000
Commercial, Percent	100.00%	100.00%
Total Mortgage Loans held-for-investment	$ 313,421,000	$ 298,650,000
Total Mortgage Loans held-for investment, Percent	100.00%	100.00%
Weighted average debt service coverage ratios	2.2
Weighted average loan-to-value ratios (less than)	60.00%
Credit losses associated with commercial mortgage loans	$ 0

INVESTMENTS (Other Investments)

INVESTMENTS (Other Investments) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Other Investments [Line Items]
Other investments, at fair value	$ 795,331	$ 787,787
Percentage of total fair value	100.00%	100.00%
Long/short equity funds
Other Investments [Line Items]
Other investments, at fair value	$ 29,324	$ 26,779
Percentage of total fair value	4.00%	3.00%
Redemption notice period	60 days	60 days
Multi-strategy funds
Other Investments [Line Items]
Other investments, at fair value	$ 149,509	$ 153,883
Percentage of total fair value	19.00%	20.00%
Multi-strategy funds | Other Redemption Restriction
Other Investments [Line Items]
Unfunded commitments related to other investments	$ 53,000	$ 84,000
Multi-strategy funds | Minimum
Other Investments [Line Items]
Redemption notice period	60 days	60 days
Multi-strategy funds | Minimum | Other Redemption Restriction
Other Investments [Line Items]
Investment term	2 years
Multi-strategy funds | Maximum
Other Investments [Line Items]
Redemption notice period	90 days	95 days
Event-driven funds
Other Investments [Line Items]
Other investments, at fair value	$ 5,914	$ 13,936
Percentage of total fair value	1.00%	2.00%
Redemption notice period		45 days
Direct lending funds
Other Investments [Line Items]
Other investments, at fair value	$ 272,752	$ 274,478
Percentage of total fair value	34.00%	35.00%
Direct lending funds | Other Redemption Restriction
Other Investments [Line Items]
Unfunded commitments related to other investments	$ 200,000	$ 210,000
Optional extension of investment term	3 years
Direct lending funds | Minimum | Other Redemption Restriction
Other Investments [Line Items]
Investment term	5 years
Direct lending funds | Maximum | Other Redemption Restriction
Other Investments [Line Items]
Investment term	10 years
Private equity funds
Other Investments [Line Items]
Other investments, at fair value	$ 61,526	$ 64,566
Percentage of total fair value	8.00%	8.00%
Unfunded commitments related to other investments	$ 16,000	$ 16,000
Investment term	10 years
Real estate funds
Other Investments [Line Items]
Other investments, at fair value	$ 111,169	$ 84,202
Percentage of total fair value	14.00%	11.00%
Real estate funds | Other Redemption Restriction
Other Investments [Line Items]
Unfunded commitments related to other investments	$ 115,000	$ 147,000
Real estate funds | Minimum | Other Redemption Restriction
Other Investments [Line Items]
Investment term	7 years
CLO-Equities
Other Investments [Line Items]
Other investments, at fair value	$ 18,022	$ 21,271
Percentage of total fair value	1.00%	2.00%
Other privately held investments
Other Investments [Line Items]
Other investments, at fair value	$ 47,685	$ 44,518
Percentage of total fair value	6.00%	6.00%
Overseas deposits
Other Investments [Line Items]
Other investments, at fair value	$ 99,430	$ 104,154
Percentage of total fair value	13.00%	13.00%
Hedge funds | Lockup Redemption Restriction
Other Investments [Line Items]
Fair value of other investments subject to redemption restrictions	$ 42,000	$ 27,000
Percentage of fair value of other investments subject to redemption restrictions	23.00%	14.00%
Bank Revolver Opportunity Funds
Other Investments [Line Items]
Unfunded commitments related to other investments	$ 50,000
Investment term	7 years
Optional extension of investment term	2 years

INVESTMENTS (Equity Method Inve

INVESTMENTS (Equity Method Investments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Mar. 31, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Equity method investments		$ 110,322	$ 108,103
Harrington Reinsurance Holdings Limited
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	$ 108,000
Equity method investment, ownership percentage	19.00%
Equity method investment, difference between carrying amount and underlying equity	$ 5,000

INVESTMENTS (Net Investment Inc

INVESTMENTS (Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net Investment Income [Line Items]
Gross investment income	$ 113,363	$ 107,573
Investment expenses	(6,060)	(6,574)
Net investment income	107,303	100,999
Fixed maturities
Net Investment Income [Line Items]
Gross investment income	91,382	83,958
Other investments
Net Investment Income [Line Items]
Gross investment income	6,895	13,704
Equity securities
Net Investment Income [Line Items]
Gross investment income	2,328	1,758
Mortgage loans
Net Investment Income [Line Items]
Gross investment income	3,063	3,125
Cash and cash equivalents
Net Investment Income [Line Items]
Gross investment income	5,801	4,153
Short-term investments
Net Investment Income [Line Items]
Gross investment income	$ 3,894	$ 875

INVESTMENTS (Net Investment Gai

INVESTMENTS (Net Investment Gains (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Fixed maturities and short-term investments	$ 10,437	$ 31,628
Equity securities	1,445	17,557
Gross realized investment gains	11,882	49,185
Fixed maturities and short-term investments	(20,279)	(43,535)
Equity securities	(93)	(1,276)
Gross realized investment losses	(20,372)	(44,811)
Net OTTI recognized in net income	(4,036)	(414)
Change in fair value of investment derivatives	(2,102)	2,023
Net unrealized gains (losses) on equities	27,395	(20,813)
Total net investment gains (losses)	$ 12,767	$ (14,830)

INVESTMENTS (OTTI Recognized in

INVESTMENTS (OTTI Recognized in Earnings by Asset Class) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]
Total OTTI recognized in net income	$ 4,036	$ 414
Non-U.S. government
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]
Total OTTI recognized in net income	60	0
Corporate debt
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]
Total OTTI recognized in net income	$ 3,976	$ 414

INVESTMENTS (OTTI Recognized _2

INVESTMENTS (OTTI Recognized in AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Credit Losses For Which a Portion of OTTI Was Recognized in AOCI [Roll Forward]
Balance at beginning of period	$ 510	$ 1,494
Credit impairments recognized on securities not previously impaired	0	0
Additional credit impairments recognized on securities previously impaired	0	0
Change in timing of future cash flows on securities previously impaired	0	0
Intent to sell of securities previously impaired	0	0
Securities sold/redeemed/matured	(38)	(10)
Balance at end of period	$ 472	$ 1,484

INVESTMENTS (Reverse Repurchase

INVESTMENTS (Reverse Repurchase Agreements) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Value of reverse repurchase agreements	$ 97	$ 189
Minimum required collateral for reverse repurchase agreements, expressed as a percentage of loan principal	102.00%

FAIR VALUE MEASUREMENTS (Financ

FAIR VALUE MEASUREMENTS (Financial Instruments Measured at Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	$ 11,874,518	$ 11,435,347
Equity securities	418,863	381,633
Other investments, at fair value	795,331	787,787
Short-term investments	41,853	144,040
Derivative instruments (refer to Note 5)	3,468	8,237
Total Assets	13,134,033	12,757,044
Derivative instruments (refer to Note 5)	13,837	14,522
Cash settled awards (refer to Note 8)	7,878	20,648
Total Liabilities	21,715	35,170
U.S. government and agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,973,654	1,515,697
Non-U.S. government
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	487,663	493,016
Corporate debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	4,838,265	4,876,921
Agency RMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,705,962	1,643,308
CMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,052,140	1,092,530
Non-Agency RMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	47,411	40,687
ABS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,613,010	1,637,603
Municipals
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	156,413	135,585
Common stocks
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	585	527
Exchange-traded funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	271,608	236,839
Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	146,670	144,267
Hedge funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	184,747	194,598
Direct lending funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	272,752	274,478
Private equity funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	61,526	64,566
Real estate funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	111,169	84,202
Other privately held investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	47,685	44,518
CLO-Equities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	18,022	21,271
Overseas deposits
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	99,430	104,154
Quoted prices in active markets for identical assets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,958,315	1,480,466
Equity securities	272,193	237,366
Other investments, at fair value	0	0
Short-term investments	0	0
Derivative instruments (refer to Note 5)	0	0
Total Assets	2,230,508	1,717,832
Derivative instruments (refer to Note 5)	0	0
Cash settled awards (refer to Note 8)	0	0
Total Liabilities	0	0
Quoted prices in active markets for identical assets (Level 1) | U.S. government and agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,958,315	1,480,466
Quoted prices in active markets for identical assets (Level 1) | Non-U.S. government
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Quoted prices in active markets for identical assets (Level 1) | Corporate debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Quoted prices in active markets for identical assets (Level 1) | Agency RMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Quoted prices in active markets for identical assets (Level 1) | CMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Quoted prices in active markets for identical assets (Level 1) | Non-Agency RMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Quoted prices in active markets for identical assets (Level 1) | ABS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Quoted prices in active markets for identical assets (Level 1) | Municipals
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Quoted prices in active markets for identical assets (Level 1) | Common stocks
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	585	527
Quoted prices in active markets for identical assets (Level 1) | Exchange-traded funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	271,608	236,839
Quoted prices in active markets for identical assets (Level 1) | Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0	0
Quoted prices in active markets for identical assets (Level 1) | Hedge funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Direct lending funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Private equity funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Real estate funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Other privately held investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | CLO-Equities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Overseas deposits
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Significant other observable inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	9,851,890	9,868,202
Equity securities	146,670	144,267
Other investments, at fair value	99,430	104,154
Short-term investments	41,853	144,040
Derivative instruments (refer to Note 5)	3,468	8,237
Total Assets	10,143,311	10,268,900
Derivative instruments (refer to Note 5)	3,604	4,223
Cash settled awards (refer to Note 8)	7,878	20,648
Total Liabilities	11,482	24,871
Significant other observable inputs (Level 2) | U.S. government and agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	15,339	35,231
Significant other observable inputs (Level 2) | Non-U.S. government
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	487,663	493,016
Significant other observable inputs (Level 2) | Corporate debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	4,797,140	4,827,909
Significant other observable inputs (Level 2) | Agency RMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,705,962	1,643,308
Significant other observable inputs (Level 2) | CMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,040,995	1,073,396
Significant other observable inputs (Level 2) | Non-Agency RMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	47,411	40,687
Significant other observable inputs (Level 2) | ABS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,600,967	1,619,070
Significant other observable inputs (Level 2) | Municipals
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	156,413	135,585
Significant other observable inputs (Level 2) | Common stocks
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0	0
Significant other observable inputs (Level 2) | Exchange-traded funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0	0
Significant other observable inputs (Level 2) | Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	146,670	144,267
Significant other observable inputs (Level 2) | Hedge funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Significant other observable inputs (Level 2) | Direct lending funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Significant other observable inputs (Level 2) | Private equity funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Significant other observable inputs (Level 2) | Real estate funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Significant other observable inputs (Level 2) | Other privately held investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Significant other observable inputs (Level 2) | CLO-Equities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Significant other observable inputs (Level 2) | Overseas deposits
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	99,430	104,154
Significant unobservable inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	64,313	86,679
Equity securities	0	0
Other investments, at fair value	65,707	65,789
Short-term investments	0	0
Derivative instruments (refer to Note 5)	0	0
Total Assets	130,020	152,468
Derivative instruments (refer to Note 5)	10,233	10,299
Cash settled awards (refer to Note 8)	0	0
Total Liabilities	10,233	10,299
Significant unobservable inputs (Level 3) | U.S. government and agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Significant unobservable inputs (Level 3) | Non-U.S. government
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Significant unobservable inputs (Level 3) | Corporate debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	41,125	49,012
Significant unobservable inputs (Level 3) | Agency RMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Significant unobservable inputs (Level 3) | CMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	11,145	19,134
Significant unobservable inputs (Level 3) | Non-Agency RMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Significant unobservable inputs (Level 3) | ABS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	12,043	18,533
Significant unobservable inputs (Level 3) | Municipals
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0	0
Significant unobservable inputs (Level 3) | Common stocks
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0	0
Significant unobservable inputs (Level 3) | Exchange-traded funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0	0
Significant unobservable inputs (Level 3) | Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0	0
Significant unobservable inputs (Level 3) | Hedge funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Significant unobservable inputs (Level 3) | Direct lending funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Significant unobservable inputs (Level 3) | Private equity funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Significant unobservable inputs (Level 3) | Real estate funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Significant unobservable inputs (Level 3) | Other privately held investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	47,685	44,518
Significant unobservable inputs (Level 3) | CLO-Equities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	18,022	21,271
Significant unobservable inputs (Level 3) | Overseas deposits
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Fair value based on NAV practical expedient
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	630,194	617,844
Fair value based on NAV practical expedient | Hedge funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	184,747	194,598
Fair value based on NAV practical expedient | Direct lending funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	272,752	274,478
Fair value based on NAV practical expedient | Private equity funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	61,526	64,566
Fair value based on NAV practical expedient | Real estate funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	111,169	84,202
Fair value based on NAV practical expedient | Other privately held investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Fair value based on NAV practical expedient | CLO-Equities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	0	0
Fair value based on NAV practical expedient | Overseas deposits
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments, at fair value	$ 0	$ 0

FAIR VALUE MEASUREMENTS (Signif

FAIR VALUE MEASUREMENTS (Significant Unobservable Inputs) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Fair Value Inputs Assets Quantitative Information [Line Items]
Other investments, at fair value	$ 795,331	$ 787,787
Derivatives - Other underwriting-related derivatives	(13,837)	(14,522)
Significant unobservable inputs (Level 3)
Fair Value Inputs Assets Quantitative Information [Line Items]
Other investments, at fair value	65,707	65,789
Derivatives - Other underwriting-related derivatives	(10,233)	$ (10,299)
Discounted cash flow | Significant unobservable inputs (Level 3)
Fair Value Inputs Assets Quantitative Information [Line Items]
Derivatives - Other underwriting-related derivatives	(10,233)
Discounted cash flow | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Other investments, at fair value	$ 18,022
Estimated maturity dates	7 years
Discounted cash flow | Significant unobservable inputs (Level 3) | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Other investments, at fair value	$ 47,685
Weighted average | Discounted cash flow | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Estimated maturity dates	7 years
Default rates | Discounted cash flow | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input	0.030
Default rates | Weighted average | Discounted cash flow | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input	0.030
Loss severity rate | Discounted cash flow | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input	0.350
Loss severity rate | Weighted average | Discounted cash flow | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input	0.350
Collateral spreads | Discounted cash flow | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input	0.030
Collateral spreads | Weighted average | Discounted cash flow | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input	0.030
Discount rate | Discounted cash flow | Significant unobservable inputs (Level 3)
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	0.023
Discount rate | Minimum | Discounted cash flow | Significant unobservable inputs (Level 3) | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input	0.030
Discount rate | Maximum | Discounted cash flow | Significant unobservable inputs (Level 3) | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input	0.080
Discount rate | Weighted average | Discounted cash flow | Significant unobservable inputs (Level 3)
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	0.023
Discount rate | Weighted average | Discounted cash flow | Significant unobservable inputs (Level 3) | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Unobservable input	0.065

FAIR VALUE MEASUREMENTS (Change

FAIR VALUE MEASUREMENTS (Changes in Level 3 for Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Total liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	$ 10,299	$ 11,510
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in earnings	(66)	(568)
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	0	0
Closing balance	10,233	10,942
Change in unrealized investment gain/loss relating to assets held at the reporting date	(66)	(568)
Fixed maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	86,679	52,897
Transfers into Level 3	0	0
Transfers out of Level 3	(21,169)	(4,279)
Included in net income	(696)	(118)
Included in OCI	929	1,403
Purchases	9,750	0
Sales	(5,547)	(2,536)
Settlements/ distributions	(5,633)	(3,896)
Closing balance	64,313	43,471
Change in unrealized investment gain/loss relating to assets held at the reporting date	0	0
Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	65,789	77,843
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	1,082	2,362
Included in OCI	0	0
Purchases	2,500	3,111
Sales	0	(1,500)
Settlements/ distributions	(3,664)	(4,473)
Closing balance	65,707	77,343
Change in unrealized investment gain/loss relating to assets held at the reporting date	1,082	2,362
Other assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	0	25,090
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	0	(90)
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	0	0
Closing balance	0	25,000
Change in unrealized investment gain/loss relating to assets held at the reporting date	0	(90)
Total assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	152,468	155,830
Transfers into Level 3	0	0
Transfers out of Level 3	(21,169)	(4,279)
Included in net income	386	2,154
Included in OCI	929	1,403
Purchases	12,250	3,111
Sales	(5,547)	(4,036)
Settlements/ distributions	(9,297)	(8,369)
Closing balance	130,020	145,814
Change in unrealized investment gain/loss relating to assets held at the reporting date	1,082	2,272
Corporate debt | Fixed maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	49,012	52,897
Transfers into Level 3	0	0
Transfers out of Level 3	0	(4,279)
Included in net income	(696)	(118)
Included in OCI	624	1,403
Purchases	0	0
Sales	(5,547)	(2,536)
Settlements/ distributions	(2,268)	(3,896)
Closing balance	41,125	43,471
Change in unrealized investment gain/loss relating to assets held at the reporting date	0	0
CMBS | Fixed maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	19,134	0
Transfers into Level 3	0	0
Transfers out of Level 3	(4,767)	0
Included in net income	0	0
Included in OCI	143	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	(3,365)	0
Closing balance	11,145	0
Change in unrealized investment gain/loss relating to assets held at the reporting date	0	0
ABS | Fixed maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	18,533	0
Transfers into Level 3	0	0
Transfers out of Level 3	(16,402)	0
Included in net income	0	0
Included in OCI	162	0
Purchases	9,750	0
Sales	0	0
Settlements/ distributions	0	0
Closing balance	12,043	0
Change in unrealized investment gain/loss relating to assets held at the reporting date	0	0
Other privately held investments | Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	44,518	46,430
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	667	746
Included in OCI	0	0
Purchases	2,500	3,111
Sales	0	(1,500)
Settlements/ distributions	0	0
Closing balance	47,685	48,787
Change in unrealized investment gain/loss relating to assets held at the reporting date	667	746
CLO-Equities | Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	21,271	31,413
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	415	1,616
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	(3,664)	(4,473)
Closing balance	18,022	28,556
Change in unrealized investment gain/loss relating to assets held at the reporting date	415	1,616
Derivative instruments | Other liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	10,299	11,510
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in earnings	(66)	(568)
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	0	0
Closing balance	10,233	10,942
Change in unrealized investment gain/loss relating to assets held at the reporting date	(66)	(568)
Insurance-linked securities | Other assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	0	25,090
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	0	(90)
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	0	0
Closing balance	0	25,000
Change in unrealized investment gain/loss relating to assets held at the reporting date	$ 0	$ (90)

FAIR VALUE MEASUREMENTS (Other

FAIR VALUE MEASUREMENTS (Other Fair Value Narrative) (Details) $ in Millions	Mar. 31, 2019USD ($)hedge_fund	Dec. 31, 2018USD ($)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Number of hedge funds with reporting lag | hedge_fund	2
Entities that calculate net asset value per share, reporting lag, percent other investments	62.00%	61.00%
Reported Value Measurement
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	$ 1,342	$ 1,342
Estimate of fair value measurement
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	$ 1,360	$ 1,334

DERIVATIVE INSTRUMENTS (Schedul

DERIVATIVE INSTRUMENTS (Schedule of Derivative Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative Asset Fair Value	$ 3,468	$ 8,237
Derivative Liability Fair Value	13,837	14,522
Other assets | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative Asset Fair Value	3,468	8,237
Other liabilities | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative Liability Fair Value	13,837	14,522
Investment Portfolio | Foreign exchange forward contracts | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative notional amount	172,306	79,336
Investment Portfolio | Foreign exchange forward contracts | Other assets | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative Asset Fair Value	818	262
Investment Portfolio | Foreign exchange forward contracts | Other liabilities | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative Liability Fair Value	284	531
Investment Portfolio | Interest rate swaps | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative notional amount	85,000	150,000
Investment Portfolio | Interest rate swaps | Other assets | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative Asset Fair Value	984	0
Investment Portfolio | Interest rate swaps | Other liabilities | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative Liability Fair Value	0	1,116
Underwriting Portfolio | Foreign exchange forward contracts | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative notional amount	543,174	737,419
Underwriting Portfolio | Foreign exchange forward contracts | Other assets | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative Asset Fair Value	1,666	7,975
Underwriting Portfolio | Foreign exchange forward contracts | Other liabilities | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative Liability Fair Value	3,320	2,576
Underwriting Portfolio | Other underwriting-related contracts | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative notional amount	85,000	85,000
Underwriting Portfolio | Other underwriting-related contracts | Other assets | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative Asset Fair Value	0	0
Underwriting Portfolio | Other underwriting-related contracts | Other liabilities | Not Designated as Hedging Instruments
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative Liability Fair Value	$ 10,233	$ 10,299

DERIVATIVE INSTRUMENTS (Offsett

DERIVATIVE INSTRUMENTS (Offsetting Assets and Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative assets - gross amounts	$ 6,115	$ 11,967
Derivative assets - gross amounts offset	(2,647)	(3,730)
Derivative assets- net amounts	3,468	8,237
Derivative liabilities - gross amounts	16,484	18,252
Derivative liabilities - gross amounts offset	(2,647)	(3,730)
Derivative liabilities- net amounts	$ 13,837	$ 14,522

DERIVATIVE INSTRUMENTS (Other U

DERIVATIVE INSTRUMENTS (Other Underwriting-related Risks) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	$ (12,272)	$ 10,692
Investment Portfolio | Foreign exchange forward contracts | Net investment gains (losses)
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	752	(1,191)
Investment Portfolio | Interest rate swaps | Net investment gains (losses)
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	(2,854)	3,214
Underwriting Portfolio | Foreign exchange forward contracts | Foreign exchange gains (losses)
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	(10,517)	7,768
Underwriting Portfolio | Other underwriting-related contracts | Other insurance related income (losses)
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	$ 347	$ 901

RESERVE FOR LOSSES AND LOSS E_3

RESERVE FOR LOSSES AND LOSS EXPENSES (Reserve Roll-Forward) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Reconciliation of Beginning and Ending Gross Unpaid Losses and Loss Expenses
Gross reserve for losses and loss expenses, beginning of period	$ 12,280,769	$ 12,997,553
Less reinsurance recoverable on unpaid losses, beginning of period	(3,501,669)	(3,159,514)
Net reserve for unpaid losses and loss expenses, beginning of period	8,779,100	9,838,039
Net incurred losses and loss expenses related to:
Current year	678,700	715,652
Prior years	(14,672)	(54,307)
Net incurred losses and loss expenses	664,028	661,345
Net paid losses and loss expenses related to:
Current year	(37,600)	(48,814)
Prior years	(691,558)	(675,393)
Net paid losses and loss expenses	(729,158)	(724,207)
Foreign exchange and other	6,460	(726,781)
Net reserve for unpaid losses and loss expenses, end of period	8,720,430	9,048,396
Reinsurance recoverable on unpaid losses, end of period	3,555,341	2,986,247
Gross reserve for losses and loss expenses, end of period	$ 12,275,771	$ 12,034,643

RESERVE FOR LOSSES AND LOSS E_4

RESERVE FOR LOSSES AND LOSS EXPENSES (Prior year development) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development	$ 14,672	$ 54,307
Insurance
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development	6,913	22,775
Reinsurance
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development	$ 7,759	$ 31,532

RESERVE FOR LOSSES AND LOSS E_5

RESERVE FOR LOSSES AND LOSS EXPENSES (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Current year		$ 678,700	$ 715,652
Net favorable (adverse) prior year reserve development		14,672	54,307
Short Tail Reserving Class Insurance And Reinsurance Business
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development		(33,000)	37,000
Reinsurance Credit and Surety
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development		10,000	6,000
Liability Reinsurance Business
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development		12,000	2,000
Motor Reinsurance Business
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development		12,000	3,000
Catastrophe and Weather-related Events
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Current year		11,000	35,000
Reinsurance
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development		7,759	31,532
Reinsurance | Short Tail Reserving Class Insurance And Reinsurance Business
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development		(29,000)
Reinsurance | Professional Lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development			9,000
Insurance
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development		6,913	22,775
Insurance | Short Tail Reserving Class Insurance And Reinsurance Business
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development		(22,000)
Insurance | Marine | Short Tail Reserving Class Insurance And Reinsurance Business
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development		16,000
Insurance | Professional Lines
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development		$ 6,000	4,000
Insurance | Liability Insurance Business
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net favorable (adverse) prior year reserve development			$ (7,000)
Syndicate 2007
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Policyholder benefits and claims incurred, assumed and ceded	$ 819,000

EARNINGS PER COMMON SHARE (Deta

EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings per common share
Net income	$ 108,781	$ 73,202
Less: Preferred share dividends	10,656	10,656
Net income available to common shareholders	$ 98,125	$ 62,546
Weighted average common shares outstanding - basic (in shares)	83,725	83,322
Earnings per common share (in usd per share)	$ 1.17	$ 0.75
Earnings per diluted common share
Net income available to common shareholders	$ 98,125	$ 62,546
Weighted average common shares outstanding - basic (in shares)	83,725	83,322
Share-based compensation plans (in shares)	547	399
Weighted average common shares outstanding - diluted (in shares)	84,272	83,721
Earnings per diluted common share (in usd per share)	$ 1.16	$ 0.75
Weighted average anti-dilutive shares excluded from the dilutive computation (in shares)	601	810

SHARE-BASED COMPENSATION (Detai

SHARE-BASED COMPENSATION (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Abstract]
Liability for cash-settled restricted stock units	$ 7,878		$ 20,648
Restricted Stock Units (RSUs)
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]
Share based compensation costs incurred	15,000	$ 16,000
Tax benefit related to share-based compensation costs	2,000	2,000
Fair value - vested during period	48,000	42,000
Unrecognized compensation costs	$ 121,000	$ 137,000
Unrecognized compensation costs - weighted average period expected to be recognized	2 years 11 months	3 years
Restricted Stock Units (RSUs) | Cash Settled
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Abstract]
Liability for cash-settled restricted stock units	$ 8,000	$ 9,000
Performance Vesting Restricted Stock Units | Share Settled
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Roll Forward]
Nonvested restricted stock units - beginning of period (in shares)	232
Granted (in shares)	127
Vested (in shares)	(61)
Forfeited (in shares)	0
Nonvested restricted stock units - end of period (in shares)	298
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Abstract]
Weighted average grant date fair value - beginning of period (in usd per share)	$ 54.54
Weighted average grant date fair value - granted (in usd per share)	54.70
Weighted average grant date fair value - vested (in usd per share)	53.82
Weighted average grant date fair value - forfeited (in usd per share)	0
Weighted average grant date fair value - end of period (in usd per share)	$ 54.76
Performance Vesting Restricted Stock Units | Cash Settled
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Roll Forward]
Nonvested restricted stock units - beginning of period (in shares)	27
Granted (in shares)	0
Vested (in shares)	(12)
Forfeited (in shares)	0
Nonvested restricted stock units - end of period (in shares)	15
Service Based Restricted Stock Units | Share Settled
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Roll Forward]
Nonvested restricted stock units - beginning of period (in shares)	1,411
Granted (in shares)	508
Vested (in shares)	(445)
Forfeited (in shares)	(74)
Nonvested restricted stock units - end of period (in shares)	1,400
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Abstract]
Weighted average grant date fair value - beginning of period (in usd per share)	$ 54.12
Weighted average grant date fair value - granted (in usd per share)	54.67
Weighted average grant date fair value - vested (in usd per share)	54.04
Weighted average grant date fair value - forfeited (in usd per share)	54.84
Weighted average grant date fair value - end of period (in usd per share)	$ 54.31
Service Based Restricted Stock Units | Cash Settled
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Roll Forward]
Nonvested restricted stock units - beginning of period (in shares)	932
Granted (in shares)	349
Vested (in shares)	(320)
Forfeited (in shares)	(35)
Nonvested restricted stock units - end of period (in shares)	926

SHAREHOLDERS' EQUITY (Common Sh

SHAREHOLDERS' EQUITY (Common Shares Issued and Outstanding) (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued, balance at beginning of period (in shares)	176,580
Total shares issued at end of period (in shares)	176,580
Treasury shares, balance at beginning of period (in shares)	(92,994)
Total treasury shares at end of period (in shares)	(92,646)
Total shares outstanding (in shares)	83,934		83,586
Common stocks
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued, balance at beginning of period (in shares)	176,580	176,580
Shares issued (in shares)	0	0
Total shares issued at end of period (in shares)	176,580	176,580
Treasury shares, balance at beginning of period (in shares)	(92,994)	(93,419)
Shares repurchased (in shares)	(157)	(149)
Shares reissued (in shares)	505	506
Total treasury shares at end of period (in shares)	(92,646)	(93,062)
Total shares outstanding (in shares)	83,934	83,518

SHAREHOLDERS' EQUITY (Treasury

SHAREHOLDERS' EQUITY (Treasury Shares) (Details) - Common stocks - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Treasury Shares [Line Items]
Total shares (in shares)	157	149
Total cost	$ 9,003	$ 7,163
Average price per share (in usd per share)	$ 57.17	$ 48.08
In the Open Market
Treasury Shares [Line Items]
Total shares (in shares)	0	0
Total cost	$ 0	$ 0
Average price per share (in usd per share)	$ 0	$ 0
From Employees
Treasury Shares [Line Items]
Total shares (in shares)	157	149
Total cost	$ 9,003	$ 7,163
Average price per share (in usd per share)	$ 57.17	$ 48.08

SHAREHOLDERS' EQUITY (Narrative

SHAREHOLDERS' EQUITY (Narrative) (Details) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Class of Stock [Line Items]
Cash dividends declared per common share (in usd per share)	$ 0.4	$ 0.39
Series D Preferred Shares
Class of Stock [Line Items]
Cash dividends declared per preferred share (in usd per share)	0.34375	0.34375
Series E Preferred Shares
Class of Stock [Line Items]
Cash dividends declared per preferred share (in usd per share)	$ 34.375	$ 34.375

DEBT AND FINANCING ARRANGEMEN_2

DEBT AND FINANCING ARRANGEMENTS (Details) - Letter of Credit - USD ($)	Mar. 28, 2019	Mar. 28, 2018
LOC Facility
Line of Credit Facility [Line Items]
Line of credit facility	$ 750,000,000	$ 750,000,000
LOC Facility Two
Line of Credit Facility [Line Items]
Line of credit facility	250,000,000
LOC Facility Three
Line of Credit Facility [Line Items]
Line of credit facility	$ 500,000,000

LEASES - Additional Information

LEASES - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 7,034	$ 7,000
Operating lease liabilities	144,298		$ 0
Alpharetta, Georgia
Lessee, Lease, Description [Line Items]
Operating lease liabilities	$ 40,000
Term of contract	15 years

LEASES - Lease Costs (Details)

LEASES - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Leases [Abstract]
Operating lease expense	$ 6,930
Short-term lease expense	646
Sublease income	(542)
Operating lease expense	7,034	$ 7,000
Operating cash outflows from operating leases	6,536
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 0
Weighted-average remaining lease term - operating leases	8 years 9 months
Weighted-average discount rate - operating lease	4.70%

LEASES - Operating Lease Liabil

LEASES - Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Remainder of 2019	$ 19,818
2020	22,545
2021	22,451
2022	23,165
2023	19,042
Later years	72,536
Discount	35,259
Total discounted operating lease liabilities	$ 144,298	$ 0
2019		28,240
2020		25,331
2021		27,025
2022		28,012
2023		23,801
Operating LeaLater yearsses, Future Minimum Payments, Due Thereafter		118,497
Total discounted operating lease liabilities		$ 250,906

TRANSACTION AND REORGANIZATIO_2

TRANSACTION AND REORGANIZATION EXPENSES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Restructuring and Related Activities [Abstract]
Transaction and reorganization expenses	$ 14,820	$ 13,054

OTHER COMPREHENSIVE INCOME (L_3

OTHER COMPREHENSIVE INCOME (LOSS) (Tax Effects of Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Before tax amount
Total other comprehensive income (loss), net of tax	$ 223,342	$ (108,517)
Tax (expense) benefit
Total other comprehensive income (loss), net of tax	(17,137)	(1,619)
Net of tax amount
Total other comprehensive income (loss), net of tax	206,205	(110,136)
Available for sale investments
Before tax amount
Unrealized investment gains (losses) arising during the period	206,806	(105,675)
Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income	13,874	(4,112)
Total other comprehensive income (loss), net of tax	220,680	(109,787)
Tax (expense) benefit
Unrealized investment gains (losses) arising during the period	(16,633)	(6,516)
Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income	(504)	4,897
Total other comprehensive income (loss), net of tax	(17,137)	(1,619)
Net of tax amount
Unrealized investment gains (losses) arising during the period	190,173	(112,191)
Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income	13,370	785
Total other comprehensive income (loss), net of tax	203,543	(111,406)
Non-credit portion of OTTI losses
Before tax amount
Total other comprehensive income (loss), net of tax	0	0
Tax (expense) benefit
Total other comprehensive income (loss), net of tax	0	0
Net of tax amount
Total other comprehensive income (loss), net of tax	0	0
Foreign currency translation adjustment
Before tax amount
Total other comprehensive income (loss), net of tax	2,662	1,270
Tax (expense) benefit
Total other comprehensive income (loss), net of tax	0	0
Net of tax amount
Total other comprehensive income (loss), net of tax	$ 2,662	$ 1,270

OTHER COMPREHENSIVE INCOME (L_4

OTHER COMPREHENSIVE INCOME (LOSS) (Reclassifications Out of AOCI Into Net Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Reclassification out of accumulated comprehensive income into net income available to common shareholders [Line Items]
Other realized investment gains (losses)	$ 16,803	$ (14,416)
OTTI losses	(4,036)	(414)
Total before tax	107,796	72,166
Income tax (expense) benefit	(1,234)	1,036
Net income available to common shareholders	98,125	62,546
Unrealized investment gains (losses) on available for sale investments | Reclassification out of Accumulated Other Comprehensive Income
Reclassification out of accumulated comprehensive income into net income available to common shareholders [Line Items]
Other realized investment gains (losses)	(9,838)	4,526
OTTI losses	(4,036)	(414)
Total before tax	(13,874)	4,112
Income tax (expense) benefit	504	(4,897)
Net income available to common shareholders	$ (13,370)	$ (785)

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - Subsequent Event - USD ($)	Apr. 01, 2019	Apr. 03, 2019
Senior Notes | Senior Notes Due 2019 Axis Specialty Finance PLC 2014
Subsequent Event [Line Items]
Maturities of senior debt	$ 250,000,000
Debt instrument, interest rate, stated percentage	2.65%
Senior Notes | Senior Notes Due 2045 Axis Specialty Finance PLC 2014
Subsequent Event [Line Items]
Debt instrument, interest rate, stated percentage		5.15%
Debt instrument, face amount		$ 250,000,000
AXIS Specialty Finance PLC
Subsequent Event [Line Items]
Ownership percentage by parent	100.00%