AXIS Capital Holdings Limited (AXS) 10-K 26 Feb 19 2018 FY Annual report Financial data

DOCUMENT AND ENTITY INFORMATION

DOCUMENT AND ENTITY INFORMATION - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Feb. 20, 2019	Jun. 30, 2018
DOCUMENT AND ENTITY INFORMATION [ABSTRACT]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Entity Registrant Name	AXIS CAPITAL HOLDINGS LTD
Entity Central Index Key	1,214,816
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		83,628,651
Entity Voluntary Filer	No
Entity Well-known Seasoned Issuer	Yes
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 4.6

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets
Fixed maturities, available for sale, at fair value (Amortized cost 2018: $11,616,312; 2017: $12,611,219)	$ 11,435,347	$ 12,622,006
Equity securities, at fair value (Cost 2018: $365,905; 2017: $552,867)	381,633	635,511
Mortgage loans, held for investment, at amortized cost and fair value	298,650	325,062
Other investments, at fair value	787,787	1,009,373
Equity method investments	108,103	108,597
Short-term investments, at amortized cost and fair value	144,040	83,661
Total investments	13,155,560	14,784,210
Cash and cash equivalents	1,232,814	948,626
Restricted cash and cash equivalents	597,206	415,160
Accrued interest receivable	80,335	81,223
Insurance and reinsurance premium balances receivable	3,007,296	3,012,419
Reinsurance recoverable on unpaid losses	3,501,669	3,159,514
Reinsurance recoverable on paid losses	280,233	179,326
Deferred acquisition costs	566,622	474,061
Prepaid reinsurance premiums	1,013,573	809,274
Receivable for investments sold	32,627	11,621
Goodwill	102,003	102,003
Intangible assets	241,568	257,987
Value of business acquired	35,714	206,838
Other assets	285,346	317,915
Total assets	24,132,566	24,760,177
Liabilities
Reserve for losses and loss expenses	12,280,769	12,997,553
Unearned premiums	3,635,758	3,641,399
Insurance and reinsurance balances payable	1,338,991	899,064
Senior notes and notes payable	1,341,961	1,376,529
Payable for investments purchased	111,838	100,589
Other liabilities	393,178	403,779
Total liabilities	19,102,495	19,418,913
Commitments and Contingencies
Shareholders' equity
Preferred shares	775,000	775,000
Common shares (shares issued 2018: 176,580; 2017: 176,580 shares outstanding 2018: 83,586; 2017: 83,161)	2,206	2,206
Additional paid-in capital	2,308,583	2,299,166
Accumulated other comprehensive income (loss)	(177,110)	92,382
Retained earnings	5,912,812	5,979,666
Treasury shares, at cost (2018: 92,994; 2017: 93,419)	(3,791,420)	(3,807,156)
Total shareholders’ equity	5,030,071	5,341,264
Total liabilities and shareholders’ equity	$ 24,132,566	$ 24,760,177

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Fixed maturities, available for sale, amortized cost	$ 11,616,312	$ 12,611,219
Cost	365,905	552,867
Commitments and Contingencies
Common shares, shares issued (in shares)	176,580	176,580
Common shares, shares outstanding (in shares)	83,586	83,161
Treasury shares (in shares)	92,994	93,419

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Net premiums earned	$ 4,791,495	$ 4,148,760	$ 3,705,625
Net investment income	438,507	400,805	353,335
Other insurance related income (losses)	10,622	(1,240)	7,222
Bargain purchase gain	0	15,044	0
Net investment gains (losses):
Other-than-temporary impairment (OTTI) losses	(9,733)	(14,493)	(26,210)
Other realized and unrealized investment gains (losses)	(140,485)	42,719	(34,315)
Total net investment gains (losses)	(150,218)	28,226	(60,525)
Total revenues	5,090,406	4,591,595	4,005,657
Expenses
Net losses and loss expenses	3,190,287	3,287,772	2,204,197
Acquisition costs	968,835	823,591	746,876
General and administrative expenses	627,389	579,428	602,717
Foreign exchange losses (gains)	(29,165)	134,737	(121,295)
Interest expense and financing costs	67,432	54,811	51,360
Transaction and reorganization expenses	66,940	26,718	0
Amortization of value of business acquired	172,332	50,104	0
Amortization of intangible assets	13,814	2,543	0
Total expenses	5,077,864	4,959,704	3,483,855
Income (loss) before income taxes and interest in income (loss) of equity method investments	12,542	(368,109)	521,802
Income tax (expense) benefit	29,486	7,542	(6,340)
Interest in income (loss) of equity method investments	993	(8,402)	(2,094)
Net income (loss)	43,021	(368,969)	513,368
Preferred share dividends	42,625	46,810	46,597
Loss on repurchase of preferred shares	0	0	1,309
Net income (loss) available (attributable) to common shareholders	$ 396	$ (415,779)	$ 465,462
Earnings (loss) per common share:
Earnings (loss) per common share (in dollars per share)	$ 0	$ (4.94)	$ 5.13
Earnings (loss) per diluted common share (in dollars per share)	$ 0	$ (4.94)	$ 5.08
Weighted average common shares outstanding (in shares)	83,501	84,108	90,772
Weighted average diluted common shares outstanding (in shares)	84,007	84,108	91,547

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 43,021	$ (368,969)	$ 513,368
Other comprehensive income (loss), net of tax:
Unrealized investment gains (losses) arising during the year	(291,731)	205,419	5,072
Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income (loss)	100,902	(33,134)	62,190
Unrealized investment gains (losses) arising during the year, net of reclassification adjustment	(190,829)	172,285	67,262
Foreign currency translation adjustment	(11,165)	41,938	(638)
Total other comprehensive income (loss), net of tax	(201,994)	214,223	66,624
Comprehensive income (loss)	$ (158,973)	$ (154,746)	$ 579,992

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred shares	Common stocks	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						$ 0		$ 0
Cumulative effect of adoption of ASU | Accounting Standards Update 2016-01						0		0
Balance at beginning of year at Dec. 31, 2015		$ 627,843	$ 2,202	$ 2,241,388	$ (188,465)	(149,585)	$ (38,880)	6,194,353	$ (3,010,439)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued		550,000	4	220
Shares reissued				(19,303)					20,691
Shares repurchased				60,000					(571,805)
Costs associated with issuance of preferred shares				(18,055)
Share-based compensation expense				35,607
Unrealized gains (losses) arising during the year, net of reclassification adjustment	$ 67,262					67,262
Foreign currency translation adjustment	(638)						(638)
Net income (loss)	513,368							513,368
Preferred share dividends								(46,597)
Loss on repurchase of preferred shares		(51,769)						(1,309)
Common share dividends								(132,188)
Balance at end of year at Dec. 31, 2016	6,272,370	1,126,074	2,206	2,299,857	(121,841)	(82,323)	(39,518)	6,527,627	(3,561,553)
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
Shares issued		0	0	0
Shares reissued				(39,368)					40,255
Shares repurchased				0					(285,858)
Costs associated with issuance of preferred shares				0
Share-based compensation expense				38,677
Unrealized gains (losses) arising during the year, net of reclassification adjustment	172,285					172,285
Foreign currency translation adjustment	41,938						41,938
Net income (loss)	(368,969)							(368,969)
Preferred share dividends								(46,810)
Loss on repurchase of preferred shares		(351,074)						0
Common share dividends								(132,182)
Balance at end of year at Dec. 31, 2017	5,341,264	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]
Cumulative effect of adoption of ASU | Accounting Standards Update 2018-02						2,106		(2,106)
Cumulative effect of adoption of ASU | Accounting Standards Update 2016-01						(69,604)		69,604
Shares issued		0	0	0
Shares reissued				(24,088)					25,816
Shares repurchased				0					(10,080)
Costs associated with issuance of preferred shares				0
Share-based compensation expense				33,505
Unrealized gains (losses) arising during the year, net of reclassification adjustment	(190,829)					(190,829)
Foreign currency translation adjustment	(11,165)						(11,165)
Net income (loss)	43,021							43,021
Preferred share dividends								(42,625)
Loss on repurchase of preferred shares		0						0
Common share dividends								(134,748)
Balance at end of year 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)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income (loss)	$ 43,021	$ (368,969)	$ 513,368
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Net investment (gains) losses	144,297	(28,226)	60,525
Net realized and unrealized gains on other investments	(45,153)	(72,763)	(38,669)
Amortization of fixed maturities	24,663	43,292	65,921
Interest in income (loss) of equity method investments	495	8,402	2,094
Amortization of value of business acquired	172,332	50,104	0
Other amortization and depreciation	9,795	31,367	24,573
Share-based compensation expense, net of cash payments	34,346	12,667	52,211
Non-cash foreign exchange losses	0	24,149	0
Bargain purchase gain	0	(15,044)	0
Changes in:
Accrued interest receivable	(3,184)	(4,353)	(885)
Reinsurance recoverable balances on unpaid and paid losses	(766,690)	(131,160)	(176,532)
Deferred acquisition costs	(98,329)	(35,076)	33,212
Prepaid reinsurance premiums	(212,654)	(56,377)	(158,809)
Reserve for loss and loss expenses	442,839	1,004,578	54,476
Unearned premiums	29,760	(56,603)	198,938
Insurance and reinsurance balances, net	208,783	(81,831)	(209,895)
Other items	26,452	(64,928)	(13,804)
Net cash provided by operating activities	10,773	259,229	406,724
Purchases of:
Fixed maturities	(8,464,140)	(8,714,990)	(9,176,728)
Equity securities	(73,107)	(106,136)	(302,554)
Mortgage loans	(106,171)	(31,077)	(148,450)
Other investments	(180,126)	(153,150)	(190,370)
Equity method investments	0	(1,000)	(107,913)
Short-term investments	(305,670)	(41,609)	(190,747)
Proceeds from the sale of:
Fixed maturities	7,586,536	7,004,973	7,905,316
Equity securities	246,196	448,058	305,642
Other investments	361,030	260,943	215,578
Short-term investments	178,983	49,280	54,165
Proceeds from redemption of fixed maturities	1,241,214	2,009,982	1,492,588
Proceeds from redemption of short-term investments	45,831	119,427	36,546
Proceeds from the repayment of mortgage loans	133,081	56,435	5,040
Purchase of other assets	(25,103)	(42,685)	(27,149)
Purchase of subsidiaries, net	0	(466,941)	0
Net cash provided by (used in) investing activities	638,554	391,510	(129,036)
Cash flows from financing activities:
Net proceeds from issuance of debt	0	346,362	0
Repayment of notes payable	0	(67,242)	0
Net proceeds from issuance of preferred shares	0	0	531,945
Repurchase of common shares - open market	0	(261,180)	(495,426)
Taxes paid on withholding shares	(10,080)	(24,678)	(14,329)
Dividends paid - common shares	(133,502)	(135,032)	(132,323)
Repurchase of preferred shares	0	(351,074)	(51,769)
Dividends paid - preferred shares	(42,625)	(52,844)	(39,909)
Proceeds from issuance of common shares	0	0	224
Net cash used in financing activities	(186,207)	(545,688)	(201,587)
Effect of exchange rate changes on foreign currency cash, cash equivalents and restricted cash	3,114	17,228	(9,345)
Increase in cash, cash equivalents and restricted cash	466,234	122,279	66,756
Cash, cash equivalents and restricted cash - beginning of year	1,363,786	1,241,507	1,174,751
Cash, cash equivalents and restricted cash - end of year	1,830,020	1,363,786	1,241,507
Supplemental disclosures of cash flow information:
Income taxes paid	15,698	0	12,041
Interest paid	$ 64,822	$ 49,945	$ 48,875

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2016
Consideration transferred reinsurance		$ 170
Transfer from investments		$ 92
Syndicate 2,007
Consideration transferred reinsurance	$ 819
Transfer from investments	$ 600

HISTORY

HISTORY	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
HISTORY	AXIS Capital Holdings Limited ("AXIS Capital" and together with its wholly owned subsidiaries the "Company"), was incorporated on December 9, 2002, under the laws of Bermuda. The Company provides a broad range of (re)insurance products on a worldwide basis. The Company's principal operating subsidiaries, located in Bermuda, the United States (U.S.), Europe, Singapore and Canada are described below: • AXIS Specialty Limited ("AXIS Specialty Bermuda"), a Bermuda domiciled company is licensed to provide specialty insurance and treaty reinsurance products on a worldwide basis. In addition, AXIS Specialty Bermuda conducts (re)insurance business through its branch in Singapore, AXIS Specialty Limited (Singapore Branch). • AXIS Insurance Company, domiciled in Illinois and AXIS Reinsurance Company, domiciled in New York, together with AXIS Reinsurance Company (Canadian branch) are licensed to offer a range of specialty insurance and treaty reinsurance products to a variety of niche markets on a worldwide basis. AXIS Surplus Insurance Company, domiciled in the state of Illinois is eligible to write insurance on a surplus lines basis. • AXIS Specialty Europe SE ("AXIS Specialty Europe") is a European public limited liability company, incorporated as a non-life insurer under the laws of Ireland. It is a Societas Europaea (SE), or European society company, and has been registered in accordance with company law of the E.U. AXIS Specialty Europe also conducts insurance business through its branch in the United Kingdom, AXIS Specialty Europe SE ("UK Branch"). Effective January 1, 2019, AXIS Specialty Europe will also conduct insurance business through new branches in Belgium and in the Netherlands. • AXIS Re SE ("AXIS Re") is a European public limited liability company, incorporated as a reinsurer under the laws of Ireland. AXIS Re SE is also a Societas Europaea (SE). AXIS Re also conducts reinsurance business through its branch in Switzerland, AXIS Re SE, Dublin (Zurich Branch). • The Company operates in the Lloyd's of London ("Lloyd's") market through AXIS Corporate Capital UK Limited which is the sole corporate member of AXIS Syndicate 1686 ("Syndicate 1686"). Effective August 4, 2017, AXIS Managing Agency Ltd. ("AXIS Managing Agency") assumed management of Syndicate 1686, replacing the Company's third-party managing agency agreement with Asta Managing Agency Limited, which had been in place since 2014. Effective January 1, 2019, AXIS Corporate Capital UK Limited and Novae Corporate Underwriting Limited ("NCUL") will provide 70% and 30% , respectively, of Syndicate 1686's capital support. • On October 2, 2017, AXIS Specialty UK Holdings Limited, a wholly owned subsidiary of the Company, acquired a 100% ownership interest in Novae Group plc ("Novae"). Novae operates in the Lloyd's market through NCUL, the sole corporate member of Novae Syndicate 2007 ("Syndicate 2007") and owns Lloyd’s managing agency, Novae Syndicates Limited ("NSL") which operated in the Lloyd’s insurance market and managed Syndicate 2007 until January 1, 2018, when the Company received authorization from Lloyd’s for AXIS Managing Agency to commence management and oversight of Syndicate 2007. • AXIS Ventures Limited ("AXIS Ventures"), regulated by the BMA as an insurance manager, generates fee income from services provided to strategic capital partners. AXIS Ventures Reinsurance Limited ("Ventures Re") is a Bermuda domiciled insurer and is a registered segregated accounts company under the Bermuda Segregated Accounts Companies Act 2000, as amended. Ventures Re manages capital for investors interested in deploying funds directly into the property-catastrophe and other short-tail business.

SIGNIFICANT ACCOUNTING POLICIES

SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	Basis of Presentation These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") and the rules and regulations of the U.S. Securities and Exchange Commission ("SEC") and include AXIS Capital and its wholly-owned subsidiaries. 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. During the three months ended March 31, 2018, the Company realigned its accident and health business by integrating this business and its operations into the Company's insurance and reinsurance segments. Through this realignment, the Company's accident and health business benefited from the greater scale and market presence of the Company's property and casualty insurance and reinsurance businesses and operations. Financial results relating to the Company's accident and health lines of business were previously included in the Company's insurance segment. Effective January 1, 2018, accident and health results are included in the results of both the insurance and reinsurance segments of the Company. As a result of the realignment, gross premiums written for the year ended December 31, 2017 of $313 million (2016: $288 million ) and underwriting income for the year ended December 31, 2017 of $14 million (2016: $15 million ) were reclassified from the Company's insurance segment to the Company's reinsurance segment. At December 31, 2018 the Company represented reinsurance recoverable on unpaid losses separately from reinsurance recoverable on paid losses in the consolidated balance sheets. This presentation was adopted to facilitate comparison to the reconciliation of beginning and ending net reserves for unpaid losses and loss expenses (refer to Note 9 'Reserve for Losses and Loss Expenses') . These reclassifications did not impact results of operations, financial condition or liquidity. Tabular dollar and share amounts are in thousands, with the exception of per share amounts. All amounts are reported in U.S. dollars. Use of Estimates The preparation of these consolidated financial statements requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. While management believes that the amounts included in the consolidated financial statements reflect its best estimates and assumptions, actual results could differ from those estimates. The Company’s principal estimates include: • reserve for losses and loss expenses; • reinsurance recoverable on unpaid losses, including the provision for uncollectible amounts; • gross and net premiums written and net premiums earned; • fair value measurements of financial assets and liabilities; and • other-than-temporary impairments ("OTTI") in the carrying value of available-for-sale securities. The Company's significant accounting policies are as follows: a) Investments Fixed Maturities, Available-for-sale, at Fair Value Fixed maturities classified as available-for-sale are reported at fair value (refer to Note 7 ' Fair Value Measurements '). The change in fair values (net unrealized investment gains (losses)) of fixed maturities, net of tax is recognized in accumulated other comprehensive income (loss) ("AOCI") in the consolidated statement of change shareholders’ equity. Net investment income includes interest income and the amortization of market premiums and discounts and is presented net of investment expenses. Investment income is recognized when earned. Purchases and sales of fixed maturities are recorded on a trade-date basis and realized investment gains (losses) on sales of fixed maturities are determined based on the specific identification method. Realized investment gains (losses) on fixed maturities are included in net investments gains (losses) in the consolidated statements of operations. The Company recognizes investment income from fixed maturities based on the constant effective yield method, which includes an adjustment for estimated principal repayments, if applicable. The effective yield used to determine the amortization of fixed maturities subject to prepayment risk (e.g. asset-backed, mortgage-backed and other structured securities) is recalculated and adjusted periodically based upon historical and/or projected future cash flows. Adjustments to the yield for highly-rated prepayable fixed maturities are accounted for using the retrospective method. Adjustments to the yield for other prepayable fixed maturities are accounted for using the prospective method. A fixed maturity is impaired if the fair value of the investment is below amortized cost. On a quarterly basis, the Company assesses whether unrealized investment losses on fixed maturities represent impairments that are other-than-temporary. The Company's impairment review process begins with a quantitative analysis to identify securities to be evaluated for potential OTTI. For identified securities, fundamental analysis is performed that considers the following quantitative and qualitative factors: (i) the duration and the extent of the decline; (ii) the financial condition, near-term and long-term prospects of the issuer of the security; (iii) the reason for the decline (e.g. credit spread widening, credit event, foreign exchange rate movements); (iii) the historical and implied future volatility of the fair value; and (v) the collateral structure and credit support of the security, if applicable. If a fixed maturity is impaired and the Company intends to sell the security or it is more likely than not that the Company will be required to sell the security before its anticipated recovery, the impairment is considered other-than-temporary. In these instances, the full amount of the impairment is charged to net income and is included in net investment gains (losses). In instances where the Company intends to hold the impaired fixed maturity, the Company estimates the anticipated credit loss on the security and recognizes this component of the impairment in net income with a corresponding adjustment to amortized cost (new cost basis) of the security. The new cost basis is adjusted for subsequent increases in fair value where the difference between the new cost basis and the expected cash flows is accreted on a quarterly basis to net investment income over the remaining life of the fixed maturity. The Company recognizes the non-credit component of the impairment (i.e. related to interest rates, market conditions, etc.) in other comprehensive income. Equity Securities, at Fair Value Following the adoption of Accounting Standards Update ("ASU") 2016-01 "Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities , " (refer to ' New Accounting Standards Adopted in 2018' below) Equity securities are reported at fair value (refer to Note 7 ' Fair Value Measurements '). Effective January 1, 2018, following the adoption of ASU 2016-01, the change in the fair values (net unrealized investment gains (losses)) of equity securities, net of tax is recognized in net investments gains (losses) in the consolidated statements of operations. Net investment income includes dividend income and is presented net of investment expenses. Investment income is recognized when earned. Purchases and sales of equity securities are recorded on a trade-date basis and realized investment gains (losses) on sales of equity securities are determined based on the specific identification method. Realized investment gains (losses) on equity securities are included in net investments gains (losses) in the consolidated statements of operations. Prior to the Adoption of ASU 2016-01 Equity securities are reported at fair value. Prior to the adoption of ASU 2016-01, the change in the fair values (net unrealized investment gains (losses)) of equity securities, net of tax was recognized in AOCI in the consolidated statement of changes in shareholders’ equity. An equity security is impaired if the fair value of the investment is below cost. On a quarterly basis, the Company assessed whether unrealized investment losses on equity securities represented impairments that are other-than-temporary and recognized impairments on equity securities in an unrealized loss position when the Company did not have the ability and intent to hold the security for a reasonable period of time to allow for a full recovery. The full amount of the impairment was charged to net income and was included in net realized investment gains (losses) in the consolidated statements of operations. Upon recognition of an other-than-temporary impairment ("OTTI") charge, the new cost basis for the equity security was the cost for an equity security less the OTTI charge recognized in net income. The new cost basis was not adjusted for subsequent increases in fair value. Mortgage Loans Held-for-investment Mortgage loans held-for-investment are reported at amortized cost which is calculated as the unpaid principal balance, adjusted for any unamortized premium or discount, deferred fees or expenses, and is net of valuation allowances. Interest income and prepayment fees are recognized when earned. Interest income is recognized based on an effective yield method which gives effect to the amortization of premiums and accretion of discounts. Other Investments Other investments are recorded at fair value (refer to Note 7 ' Fair Value Measurements '), with both changes in fair value and realized investment gains (losses) reported in net investment income in the consolidated statements of operations. Equity Method Investments Investments in which the Company has significant influence over the operating and financial policies of the investee are classified as equity method investments and are accounted for using the equity method of accounting. In applying the equity method of accounting, investments are initially recorded at cost and are subsequently adjusted based on the Company’s proportionate share of net income or loss of the investee. Adjustments are based on the most recently available financial information from the investee. Changes in the carrying value of these investments are recorded in net income as interest in income (loss) of equity method investments. Short-term Investments Short-term investments primarily comprise highly-liquid debt securities with maturities greater than three months but less than one year from the date of purchase. These investments are carried at amortized cost, which approximates fair value. b) Cash and Cash Equivalents Cash equivalents include money-market funds, fixed interest deposits and reverse repurchase agreements with a maturity of under 90 days when purchased. Cash and cash equivalents are recorded at amortized cost, which approximates fair value due to the short-term, liquid nature of these securities. Restricted cash primarily relates to funds held in trust to support of obligations in regulatory jurisdictions where the Company operates as a non-admitted carrier and to support the underwriting activities of Syndicate 1686 and Syndicate 2007 at Lloyd's. c) Premiums and Acquisition Costs Premiums Insurance premiums written are recorded in accordance with the terms of the underlying policies. Reinsurance premiums are recorded at the inception of the contract and are estimated based on information received from ceding companies. For multi-year contracts where (re)insurance premiums are payable in annual installments, premiums are recorded at the inception of the contract based on management’s best estimate of total premiums to be received. However, premiums are normally recognized on an annual basis for multi-year contracts where the cedant has the ability to unilaterally commute or cancel coverage within the term of the policy. The remaining annual premiums are included as written at each successive anniversary date within the multi-year term. Any adjustments to insurance and reinsurance premium estimates are recognized in the period in which they are determined. (Re)insurance premiums are earned evenly over the period during which the Company is exposed to the underlying risk, which is generally one to two years with the exception of multi-year contracts. Unearned premiums represent the portion of premiums written which relates to the unexpired risks under contracts in force. Reinstatement premiums are recognized and earned at the time a loss event occurs, where the coverage limits for the remaining life of the contract are reinstated under pre-defined contract terms. The accrual of reinstatement premiums is based on estimates of losses and loss adjustment expenses, which reflects management’s judgment, as described in Note 2(d) ' Losses and Loss Expenses ' below. Premiums receivable balances are reviewed for impairment at least quarterly and an allowance is established for amounts considered uncollectible. Acquisition Costs Acquisition costs vary with and are directly related to the successful acquisition efforts of acquiring new or renewing existing (re)insurance contracts and consist primarily of fees and commissions paid to brokers and premium taxes. Acquisition costs are shown net of commissions earned on ceded reinsurance. Net acquisition costs are deferred and charged to expense as the related premium is earned. Insurance and reinsurance premiums balance receivable is presented net of acquisition costs when contract terms provide for the right of offset. Anticipated losses and loss expenses, other costs and investment income related to these premiums are considered in assessing the recoverability of deferred acquisition costs. If deferred amounts are estimated to be unrecoverable, they are expensed. Compensation expenses for personnel involved in contract acquisition, as well as advertising costs, are expensed as incurred. d) Losses and Loss Expenses Reserve for losses and loss expenses represents an estimate of the unpaid portion of the ultimate liability for losses and loss expenses for (re)insured events that have occurred at or before the balance sheet date. These amounts reflect both claims that have been reported ("case reserves") and claims that have been incurred but not yet reported ("IBNR") and are reduced for estimated amounts of salvage and subrogation recoveries. The Company reviews its reserve for losses and loss expenses on a quarterly basis. Case reserves are primarily established based on amounts reported from insureds and/or their brokers. Management estimates IBNR after reviewing detailed actuarial analyses and applying informed judgment regarding qualitative factors that may not be fully captured in the actuarial estimates. A variety of actuarial methods are utilized in this process, including the Expected Loss Ratio, Chain Ladder and Bornhuetter Ferguson methods. The estimate is highly dependent on management’s judgment as to which method(s) are most appropriate for a particular accident year and line of business. Historical claims data is often supplemented with industry benchmarks when applying these methodologies. Any adjustments to reserve for losses and loss expenses estimates are recognized in the period in which they are determined. While the Company believes that its reserves for losses and loss expenses are adequate, this estimate requires significant judgment and new information, events or circumstances may result in ultimate losses that are materially greater or less than provided for in the consolidated balance sheets. e) Reinsurance In the normal course of business, the Company purchases reinsurance protection to limit its ultimate losses from catastrophic events and to reduce its loss aggregation risk. The premiums paid to reinsurers (i.e. ceded premiums written) are expensed over the coverage period. Prepaid reinsurance premiums represent the portion of premiums ceded which relate to the unexpired term of the contracts in force. Reinstatement premiums ceded are recognized and earned at the time a loss event occurs, where the coverage limits for the remaining life of the contract are reinstated under pre-defined contract terms. Reinsurance recoverable related to case reserves is estimated on a case-by-case basis by applying the terms of any applicable reinsurance cover to individual case reserve estimates. Reinsurance recoverable related to IBNR is generally developed as part of our loss reserving process, therefore, its estimation is subject to similar risks and uncertainties as the estimation of IBNR. Reinsurance recoverable is presented net of a provision for uncollectible amounts, reflecting the amount the Company believes ultimately will not be recovered due to reinsurer insolvency, contractual disputes and/or some other reason. The Company applies case-specific provisions against reinsurance recoverable on unpaid and paid losses that it deems unlikely to be collected in full. In addition, the Company uses a default analysis to estimate the provision for uncollectible amounts on the remainder of the reinsurance recoverable balance. The estimates of reinsurance recoverable and the associated provision for uncollectible amounts require management’s judgment and are reviewed in detail on a quarterly basis. Any adjustments to the provision for uncollectible amounts are recognized in the period in which they are determined. Retroactive Reinsurance Retroactive reinsurance reimburses a ceding company for liabilities incurred as a result of past insurable events covered under contracts subject to the reinsurance. In certain instances, reinsurance contracts cover losses both on a prospective basis and on a retroactive basis and where practical the Company bifurcates the prospective and retrospective elements of these reinsurance contracts and accounts for each element separately. Initial gains in connection with retroactive reinsurance contracts are deferred and amortized into income over the settlement period while losses are recognized immediately. When changes in the estimated amount recoverable from the reinsurer or in the timing of receipts related to that amount occur, a cumulative amortization adjustment is recognized in net income in the period of the change so that the deferred gain reflects the balance that would have existed had the revised estimate been available at the inception of the reinsurance transaction. f) Foreign Exchange The functional currency of the Company and the majority of its subsidiaries is the U.S. dollar. All foreign currency transactions are initially measured and recorded in the Company’s functional currency using the rates of exchange prevailing at the transaction date. Monetary assets and liabilities denominated in foreign currency are remeasured to functional currency at the rates of exchange in effect at the balance sheet date with the resulting foreign currency gains (losses) generally being recognized in the consolidated statements of operations. Foreign currency gains (losses) related to available-for-sale investments denominated in foreign currency represent an unrealized appreciation (depreciation) in the market value of the securities and are included in the relevant component of AOCI. Non-monetary assets and liabilities denominated in foreign currency are not subsequently remeasured. The Company’s reporting currency is the U.S. dollar. Assets and liabilities of the Company's subsidiaries and branches where the functional currency is not the U.S. dollar, are translated into U.S. dollars using the rates of exchange in effect at the balance sheet date, and revenue and expenses are translated using the weighted average foreign exchange rates for the period. The effect of translation adjustments is reported as a separate component of AOCI in the consolidated statement of change shareholders’ equity. g) Share-based Compensation The Company is authorized to issue restricted shares, restricted stock units, performance units, stock options, stock appreciation rights and other equity-based awards to its employees and directors. The Company's plan includes both share-settled and cash-settled service and performance based awards. The fair value of share-settled service and performance based awards is based on the market value of the Company's common share measured at the grant date and is expensed over the requisite service period. The fair value cash-settled service and performance based awards is also based on the fair market value of Company's common shares at the grant date and is expensed over the requisite service period. In addition, the fair value of the cash-settled service and performance based awards is recognized as a liability in the consolidated balance sheet and is remeasured at the end of each reporting period. Effective, January 1, 2017, the Company made an accounting policy election to account for forfeitures when they occur. h) Derivative Instruments The Company may enter into derivative instruments such as futures, options, interest rate swaps and foreign currency forward contracts as part of its overall foreign currency risk management strategy, to obtain exposure to a particular financial market or for yield enhancement. During 2013, the Company began to write derivative based risk management products designed to address weather and commodity price risks, with the objective of generating profits on a portfolio basis. Effective July 1, 2017, the Company no longer writes derivative-based risk management products which address weather risks. From time to time the Company may also enter into (re)insurance contracts that meet the Financial Accounting Standards Board's ("FASB") definition of a derivative contract. The Company measures all derivative instruments at fair value (refer to Note 7 ' Fair Value Measurements ') and recognizes them as either assets or liabilities in the consolidated balance sheets. Subsequent changes in fair value and any realized gains or losses are recognized in the consolidated statements of operations. i) Goodwill and Intangible Assets The Company recognizes goodwill and other intangible assets in connection with certain acquisitions. Goodwill represents the excess of the purchase price paid over the fair value of the net assets acquired in these acquisition and is not amortized. Other intangible assets with a finite life are amortized over the estimated useful live of the intangible asset. Other intangible assets with an indefinite life are not amortized. The Company tests goodwill and indefinite intangible assets for potential impairment during the fourth quarter each year and between annual tests if an event occurs or changes in circumstances indicate that the asset is impaired. Such events or circumstances may include an economic downturn in a geographic market or a change in the assessment of future operations. For the purposes of evaluating goodwill for impairment, the Company may first perform a qualitative assessment to determine whether it is necessary to perform a quantitative goodwill impairment test. If determined to be necessary, the quantitative test compares the fair value of a reporting unit with its carrying amount, including goodwill. Subsequent to the adoption of ASU 2017-04, "Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment " (refer to ' New Accounting Standards Adopted in 2018' below) if the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is considered not impaired. If the carrying amount of the reporting unit exceeds the fair value, an impairment loss is recognized in an amount equal to that excess, limited to the total amount of goodwill allocated to that reporting unit. For the purposes of evaluating indefinite lived intangibles for impairment, the Company may first perform a qualitative assessment to determine whether it is necessary to perform the quantitative impairment test. If the Company elects to perform a qualitative assessment, it first assesses qualitative factors to determine whether it is more likely than not that an indefinite lived intangible asset is impaired. If the Company determines that it is not more likely than not that the indefinite lived intangible asset is impaired, the Company does not calculate the fair value of the intangible asset and perform the quantitative impairment test. For the purposes of evaluating goodwill and indefinite lived intangible assets for impairment, the Company has an unconditional option to bypass the qualitative assessment in any period and proceed directly to performing the quantitative impairment test. The Company may resume performing the qualitative assessment in any subsequent period. For other definite lived intangible asset the Company tests for recoverability whenever events or changes in circumstances indicate its carrying amount may not be recoverable. The Company recognizes an impairment loss if the carrying amount of the asset is not recoverable and exceeds its fair value. The carrying amount of a definite lived intangible asset is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. If goodwill or an intangible asset is impaired, the carrying value of the asset is reduced to fair value and a corresponding expense is recorded in the consolidated statements of operations. j) Income Taxes Certain subsidiaries and branches of the Company operate in jurisdictions where they are subject to taxation. Current and deferred income taxes are charged or credited to net income, or in certain cases to AOCI, based upon enacted tax laws and rates applicable in the relevant jurisdiction in the period in which the tax becomes accruable or realizable. Deferred income taxes are provided for all temporary differences between the bases of assets and liabilities used in the consolidated balance sheets and those used in the various jurisdictional tax returns. When the assessment indicates that it is more likely than not that a portion of a deferred tax asset will not be realized in the foreseeable future, a valuation allowance against deferred tax assets is recorded. The Company recognizes the tax benefits of uncertain tax positions only when the position is more-likely-than-not to be sustained upon audit by the relevant taxing authorities. k) Treasury Shares Common shares repurchased by the Company and not subsequently canceled are classified as treasury shares and are recorded at cost. This results in a reduction of shareholders’ equity in the consolidated balance sheets. When shares are reissued from treasury, the Company uses the average cost method to determine the cost of the reissued shares. l) New Accounting Standards Adopted in 2018 Recognition and Measurement of Financial Assets and Financial Liabilities Fixed maturities and equity securities are reported at fair value at the balance sheet date (refer to Note 7 ' Fair Value Measurements '). Effective January 1, 2018, the Company adopted ASU 2016-01 "Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities, " which: • requires equity investments (except those accounted for under the equity method of accounting, investments that are consolidated or those that meet a practicability exception) to be measured at fair value with changes in fair value recognized in net income; • simplifies the impairment assessment of equity investments without readily determinable values by requiring a qualitative assessment to identify impairment, eliminates the requirement to disclose the methods and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost, • requires the use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes; • requires separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the organization has elected to measure the liabilities in accordance with the fair value option; • requires the separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements; and • clarifies that the reporting organization should evaluate the need for a valuation allowance on a deferred tax asset related to available for sale securities in combination with the organization’s other deferred tax assets. Upon adoption of this guidance, net unrealized investment gains on equity securities of $70 million , net of deferred income taxes of $13 million , were reclassified from accumulated other comprehensive income to retained earnings. Revenue from Contracts with Customers Effective January 1, 2018, the Company adopted Accounting Standards Update ("ASU") 2014-09 "Revenue from Contracts with Customers (Topic 606)," using the modified retrospective transition approach. This guidance affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards, such as accounting for insurance contracts. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The Company generated fee income of $32 million for the year ended December 31, 2018 which is within the scope of this ASU. These fees represent service fees earned by the Company's reinsurance segment related to services provided to strategic capital partners and are recognized when the related services have been performed. Given that the timing and measurement of revenue associated with impacted contracts did not change, the adoption of this guidance did not have a material impact on the Company's results of operations, financial condition and liquidity. Classification of Certain Cash Receipts and Cash Payments Effective January 1, 2018, the Company adopted ASU 2016-15, "Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments, " which addresses diversity in practice in how eight specific cash receipts and cash payments should be presented and classified on the statement of cash flows. The adoption of this guidance did not impact the Company's results of operations, financial condition and liquidity. Restricted Cash Effective January 1, 2018, the Company adopted ASU 2016-18, "Statement of Cash Flows (Topic 230) - Restricted Cash, " which addresses diversity in practice in the classification and presentation of changes in restricted cash on the statement of cash flows. This guidance requires a statement of cash flows to explain the change during the period in the total of cash, cash equivalents, restricted cash and restricted cash equivalents. Transfers between cash and cash equivalents and restricted cash and restricted cash equivalents will no longer be presented on the statement of cash flows. To facilitate comparison of the Company's consolidated statements of cash flows, the Company adopted this guidance utilizing the full retrospective approach for all periods presented in the Company's consolidated financial statements. As a result, the Company's consolidated statements of cash flows now explains the change during the period in the total of cash, cash equivalents, and restricted cash. Therefore, restricted cash is now included with cash and cash equivalents in the reconciliation of the beginning of period and end of period total amounts shown on the statement of cash flows. The adoption of this guidance did not impact the Company's results of operations, financial condition and liquidity. Stock Compensation - Scope of Modification Accounting Effective January 1, 2018, the Company adopted ASU 2017-09 "Compensation - Stock Compensation (Topic 718) - Scope of Modification Accounting, " which provides clarity and reduces diversity in practice of applying the guidance in Topic 718 to a change to the terms or conditions of a share-based payment award. This ASU provide

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
BUSINESS COMBINATIONS	a) Acquisition of Novae Group plc On October 2, 2017 (the "closing date" or the "acquisition date"), AXIS Specialty UK Holdings Limited, a wholly owned subsidiary of the Company, acquired a 100% ownership interest in Novae Group plc ("Novae") for an aggregate purchase price of $617 million . Novae is a diversified property and casualty (re)insurance business operating through Syndicate 2007 at Lloyd’s. The results of Novae are included in the results of the Company's insurance and reinsurance segments from that date. The acquisition of Novae was undertaken to accelerate the growth strategy of the Company's international insurance business, and to significantly scale up its capabilities to enable the Company to even better serve its clients and brokers. The purchase price was allocated to the assets acquired and liabilities assumed of Novae based on estimated fair values at the closing date and the Company recognized goodwill of $54 million . The allocation of the purchase price was based on information included in Novae's audited financial statements at October 2, 2017. In addition, the Company identified finite lived intangible assets of $385 million , including Value of Business Acquired ("VOBA") which represents the present value of the expected underwriting profit within policies that were in-force at the closing date of the transaction, of $257 million and finite lived intangible assets primarily related to distribution networks of $128 million . The Company also identified indefinite lived intangible assets related to Lloyd's syndicate capacity of $95 million (refer to Note 5 'Goodwill and Intangible Assets' for further information). The fair value of the assets acquired and liabilities assumed and the allocation of the purchase price on the acquisition date are summarized in the following table: Total purchase price paid $ 616,926 Assets Investments 1,733,611 Cash and cash equivalents 191,337 Insurance and reinsurance premium balances receivable 472,180 Reinsurance recoverable on unpaid and paid losses 787,907 Prepaid reinsurance premiums 197,907 Other assets 42,696 Total assets acquired $ 3,425,638 Liabilities Reserve for losses and loss expenses 2,125,634 Unearned premiums 717,442 Insurance and reinsurance balances payable 273,405 Notes payable 101,846 Other liabilities 124,585 Total liabilities assumed $ 3,342,912 Fair value of identifiable intangible assets: Value of business acquired - definite lived intangible asset 256,942 Identifiable definite lived intangible assets 128,463 Identifiable indefinite lived intangible assets 94,748 Excess purchase price over fair value of net assets acquired assigned to goodwill $ 54,047 Significant fair value adjustments are explained as follows: • Deferred acquisition costs: To eliminate Novae's deferred acquisition costs; • Prepaid reinsurance premiums: To reflect adjustments to align premium recognition accounting policies; • VOBA: To establish the fair value of VOBA identifiable intangible asset related to the acquisition of Novae; • Goodwill: To establish the fair value of goodwill related to the acquisition of Novae; • Indefinite lived and finite lived intangible assets: To establish the fair value of identifiable intangible assets related to the acquisition of Novae and to eliminate Novae's pre-existing intangible assets; • Other assets: To reflect an investment at fair value and deferred tax assets on fair value adjustments; • Reserves for losses and loss expenses: To reflect adjustments arising from the alignment of premium recognition accounting policies and reserving methodologies, as well as the price associated with the Reinsurance to Close ("RITC") of the 2015 and prior years of account of Syndicate 2007; • Unearned premiums: To reflect adjustments to align premium recognition accounting policies; and • Other liabilities: To reflect deferred tax liabilities on fair value adjustments. Identifiable intangible assets at the acquisition date are included in intangible assets in the consolidated balance sheets and are shown in the following table: Economic useful life Indefinite lived intangible assets Lloyd's syndicate capacity $ 94,748 Indefinite Finite lived other intangible assets Distribution networks: Coverholders 63,565 12 years Large brokers 46,641 15 years Small & Mid-sized Enterprise ("SME") brokers 14,126 12 years Managing General Agent ("MGA") Contract 4,131 7 years Total 128,463 Identifiable intangible assets at October 2, 2017 $ 223,211 Identifiable intangible assets are explained as follows: • Lloyd's syndicate capacity : The value of Lloyd's syndicate capacity, which represents Novae's right to underwrite a certain allocated limit of premium in the Lloyd's market. • Distribution network : • Coverholders: The value of sales of insurance policies that result directly from relationships with insurance intermediaries who are authorized by Novae's managing agent to enter into contracts of insurance to be underwritten by Syndicate 2007, in accordance with the terms of a binding authority. • Large brokers: These relationships include Novae's large brokers and consideration was given to the expectation of the renewal of these relationships and the associated expenses. • SME brokers: These relationships consist of Novae's brokers with the exception of the large brokers listed above and consideration was given to the expectation of the renewal of these relationships and the associated expenses. • MGA contract : Represents the value of managing agent fees and profit commission Novae earns related to the provision of underwriting services to Special Purpose Arrangement, SPA 6129. Valuation methodologies applicable to identifiable intangible assets are explained as follows: • Lloyd's syndicate capacity: Lloyd's syndicate capacity was valued using the Multi-Period Excess Earnings Method, an application of the Income Approach. Key inputs used in the valuation model used for this intangible asset included projected pre-tax operating profit attributable to syndicate capacity, contributory asset charges which represent the required return on and of intangibles assets utilized to generate future revenue and operating income, and an appropriate discount rate. • Distribution network: Distribution network including coverholders, large broker and SME brokers was valued using the Distributor Method, an application of the Income Approach. Key inputs used in the valuation model used for this intangible asset included net premiums earned attributable to existing distributors, attrition rates, profit margins, projected pre-tax operating profit attributable to existing distributors, contributory asset charges which represent the required return on and of intangibles assets utilized to generate future revenue and operating income, and an appropriate discount rate. • MGA contract: MGA contract was valued using the Multi-Period Excess Earnings Method, an application of the Income Approach. Key inputs used in the valuation model used for this intangible asset included SPA 6129's stamp capacity with Lloyd's, return on stamp capacity, fee income and profit commission associated with the managing agent contract for SPA 6129, profit margins, contributory asset charges which represent the required return on and of intangibles assets utilized to generate future revenue and operating income, and an appropriate discount rate. • VOBA: VOBA was computed as the difference between the fair value of unearned obligations and the unearned premiums reserve recorded by Novae at the acquisition date. Key inputs used in the valuation model used for this intangible asset included the fair value of the unearned premium computed as the present value of future unearned cash flows, plus the present value of the costs associated with holding capital to support these exposures together with the fair value of reserves computed as the present value of future net losses and loss expense payments, plus the present value of the costs associated with holding capital to support those payments. Financial Results The following selected audited information is a summary of the results of Novae that has been included in the consolidated financial statements for the year ended December 31, 2017. From acquisition date to (in thousands) December 31, 2017 Net premiums written $ 140,635 Total revenue 191,929 Total expenses (197,895 ) Net income $ (5,966 ) Supplemental Pro Forma Information The following selected unaudited pro forma financial information is a summary of the combined results of the Company and Novae, assuming the transaction had been effected on January 1, 2016. The unaudited pro forma data is for informational purposes only and does not necessarily represent results that would have occurred if the transaction had taken place on January 1, 2016. The unaudited pro forma consolidated financial information does not consider the impact of possible revenue enhancements, expense efficiencies, or synergies that may result from the acquisition of Novae. In addition, the unaudited pro forma consolidated financial information does not include costs associated with restructuring or integration activities resulting from the acquisition of Novae. In addition to the fair value adjustments and recognition of goodwill and identifiable intangible assets, other material pro forma adjustments directly attributable to the acquisition of Novae primarily included adjustments to recognize transaction and integration related expenses, to align accounting policies, to amortize identifiable indefinite lived intangible assets and to recognize related tax impacts. Years ended December 31, 2017 2016 (in thousands) (unaudited) (unaudited) Net premiums earned $ 4,728,700 $ 4,560,800 Net income $ (468,400 ) $ 532,500 b) Acquisition of Compagnie Belge d'Assurances Aviation NV/SA On April 1, 2017 (the "closing date" or the "acquisition date"), the Company acquired a 100% ownership interest in Compagnie Belge d'Assurances Aviation NV/SA ("Aviabel"). Aviabel is an insurer operating under Belgian law that has its head office in Belgium, a branch office in the Netherlands and a reinsurance company, Aviabel RE S.A. ("Aviabel RE"), in Luxembourg. The acquisition of Aviabel was undertaken to increase its scale and relevance in the global aviation market. The purchase price was allocated to the assets acquired and liabilities assumed of Aviabel based on estimated fair values on the closing date. Consequently, the Company recognized investments with a fair value of $182 million , reserves for losses and loss expenses with a fair value of $79 million , and a bargain purchase gain of $15 million . The bargain purchase gain arose as the fair values of the net identifiable assets acquired exceeded the fair value of the consideration transferred at the acquisition date. The allocation of the purchase price was based on information included in unaudited financial statements at March 31, 2017. The fair values of the assets acquired and liabilities assumed may be subject to adjustments, which may impact the amounts recorded for the assets acquired and liabilities assumed, as well as the bargain purchase gain. The underwriting results of Aviabel are included in the underwriting results of the Company's insurance segment from the acquisition date. c) Acquisition of Contessa On September 6, 2017 (the "closing date"), the Company acquired a 100% ownership interest in Contessa Limited ("Contessa"). Contessa is a Managing General Agent that manages, underwrites, services and administers small and medium sized commercial property and casualty business on behalf of the Company. The purchase price was allocated to the assets acquired and liabilities assumed of Contessa based on estimated fair values on the closing date. Consequently, the Company recognized goodwill of $1 million . Transaction and Integration Expenses In connection with the acquisition of Novae, the Company incurred transaction and integration related expenses of $26 million ( 2017 : $27 million ). The transaction and integration related expenses included due diligence, legal, accounting, investment banking fees and expenses, as well as integration expenses related to the integration of Novae into the Company's operations and compensation-related costs associated with the termination of certain employees. These expenses are included in transaction and reorganization expenses in the consolidated statement of operations.

SEGMENT INFORMATION

SEGMENT INFORMATION	12 Months Ended
	Dec. 31, 2018
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, together with discontinued lines - Novae, which represents lines of business that Novae exited or placed into run-off in the three month periods ended December 31, 2016 and March 31, 2017. 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, together with discontinued lines - Novae, which represents lines of business that Novae exited or placed into run-off in the three month periods ended December 31, 2016 and March 31, 2017. The reinsurance segment also wrote derivative based risk management products designed to address weather and commodity price risks until July 1, 2017. The following tables present the underwriting results of the Company's reportable segments, as well as the carrying amounts of allocated goodwill and intangible assets: At and year ended December 31, 2018 Insurance Reinsurance Total Gross premiums written $ 3,797,592 $ 3,112,473 $ 6,910,065 Net premiums written 2,324,747 2,334,215 4,658,962 Net premiums earned 2,362,606 2,428,889 4,791,495 Other insurance related income 3,460 7,162 10,622 Net losses and loss expenses (1,494,323 ) (1,695,964 ) (3,190,287 ) Acquisition costs (399,193 ) (569,642 ) (968,835 ) General and administrative expenses (395,252 ) (123,916 ) (519,168 ) Underwriting income $ 77,298 $ 46,529 123,827 Corporate expenses (108,221 ) Net investment income 438,507 Net investment losses (150,218 ) Foreign exchange gains 29,165 Interest expense and financing costs (67,432 ) Transaction and reorganization expenses (66,940 ) Amortization of value of business acquired (172,332 ) Amortization of intangible assets (13,814 ) Income before income taxes and interest in income (loss) of equity method investments $ 12,542 Net loss and loss expense ratio 63.2 % 69.8 % 66.6 % Acquisition cost ratio 16.9 % 23.5 % 20.2 % General and administrative expense ratio 16.8 % 5.1 % 13.1 % Combined ratio 96.9 % 98.4 % 99.9 % Total intangible assets $ 379,285 $ — $ 379,285 At and year ended December 31, 2017 Insurance Reinsurance Total Gross premiums written $ 2,814,918 $ 2,741,355 $ 5,556,273 Net premiums written 1,775,825 2,251,318 4,027,143 Net premiums earned 1,816,438 2,332,322 4,148,760 Other insurance related income (loss) 2,944 (4,184 ) (1,240 ) Net losses and loss expenses (1,465,427 ) (1,822,345 ) (3,287,772 ) Acquisition costs (270,229 ) (553,362 ) (823,591 ) General and administrative expenses (325,368 ) (124,115 ) (449,483 ) Underwriting loss $ (241,642 ) $ (171,684 ) (413,326 ) Corporate expenses (129,945 ) Net investment income 400,805 Net investment gains 28,226 Foreign exchange losses (134,737 ) Interest expense and financing costs (54,811 ) Bargain purchase gain 15,044 Transaction and reorganization expenses (26,718 ) Amortization of value of business acquired (50,104 ) Amortization of intangible assets (2,543 ) Loss before income taxes and interest in income (loss) of equity method investments $ (368,109 ) Net loss and loss expense ratio 80.7 % 78.1 % 79.2 % Acquisition cost ratio 14.9 % 23.7 % 19.9 % General and administrative expense ratio 17.9 % 5.3 % 14.0 % Combined ratio 113.5 % 107.1 % 113.1 % Total intangible assets $ 566,828 $ — $ 566,828 At and year ended December 31, 2016 Insurance Reinsurance Total Gross premiums written $ 2,432,475 $ 2,537,733 $ 4,970,208 Net premiums written 1,519,559 2,233,415 3,752,974 Net premiums earned 1,534,282 2,171,343 3,705,625 Other insurance related income 89 7,133 7,222 Net losses and loss expenses (977,771 ) (1,226,426 ) (2,204,197 ) Acquisition costs (206,619 ) (540,257 ) (746,876 ) General and administrative expenses (327,351 ) (155,350 ) (482,701 ) Underwriting income $ 22,630 $ 256,443 279,073 Corporate expenses (120,016 ) Net investment income 353,335 Net investment losses (60,525 ) Foreign exchange gains 121,295 Interest expense and financing costs (51,360 ) Income before income taxes and interest in income (loss) of equity method investments $ 521,802 Net loss and loss expense ratio 63.7 % 56.5 % 59.5 % Acquisition cost ratio 13.5 % 24.9 % 20.2 % General and administrative expense ratio 21.3 % 7.1 % 16.2 % Combined ratio 98.5 % 88.5 % 95.9 % Total intangible assets $ 85,049 $ — $ 85,049 The following table presents gross premiums written by the geographical location of the Company's subsidiaries: Year ended December 31, 2018 2017 2016 Bermuda $ 606,452 $ 529,425 $ 465,980 Ireland 1,805,882 1,569,956 1,650,229 U.S. 2,811,537 2,814,933 2,562,789 Lloyd's of London 1,686,194 641,959 291,210 Total gross premium written $ 6,910,065 $ 5,556,273 $ 4,970,208 The following table presents net premiums earned by segment and line of business: Year ended December 31, 2018 2017 2016 Insurance Property $ 796,945 $ 543,342 $ 426,918 Marine 300,944 181,533 150,046 Terrorism 49,150 36,084 33,279 Aviation 74,203 75,107 44,980 Credit and political risk 102,825 56,432 57,964 Professional lines 570,241 519,759 510,806 Liability 229,373 188,770 169,182 Accident and health 207,777 199,121 141,107 Discontinued lines - Novae 31,148 16,290 — Total Insurance 2,362,606 1,816,438 1,534,282 Reinsurance Catastrophe 250,016 209,470 199,825 Property 317,038 304,376 272,403 Professional lines 220,687 226,622 289,868 Credit and surety 250,276 244,186 252,210 Motor 438,693 371,501 318,863 Liability 363,292 351,940 332,479 Agriculture 176,435 195,391 142,501 Engineering 67,932 66,291 62,833 Marine and other 35,570 64,449 57,322 Accident and health 299,813 289,925 243,039 Discontinued lines - Novae 9,137 8,171 — Total Reinsurance 2,428,889 2,332,322 2,171,343 Total $ 4,791,495 $ 4,148,760 $ 3,705,625

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND INTANGIBLE ASSETS	The table below provides details of goodwill and intangible assets related to the Company's insurance segment: Goodwill Intangible assets with an indefinite life Intangible assets with a finite life Total Balance at December 31, 2016 Gross amount $ 42,237 $ 26,036 $ 23,030 $ 91,303 Accumulated amortization n/a n/a (9,356 ) (9,356 ) Accumulated translation adjustment 4,911 — — 4,911 47,148 26,036 13,674 86,858 Amortization n/a n/a (1,809 ) (1,809 ) Balance at December 31, 2017 Gross amount (1) 42,237 26,036 23,030 91,303 Accumulated amortization (1) n/a n/a (11,165 ) (11,165 ) Accumulated translation adjustment 4,911 — — 4,911 47,148 26,036 11,865 85,049 Acquired during the year 54,855 94,748 387,545 537,148 Amortization n/a n/a (55,369 ) (55,369 ) Balance at December 31, 2018 Gross amount $ 97,092 $ 120,784 $ 410,575 $ 628,451 Accumulated amortization n/a n/a (66,534 ) (66,534 ) Accumulated translation adjustment 4,911 — — 4,911 102,003 120,784 344,041 566,828 Amortization n/a n/a (184,043 ) (184,043 ) Impairment charge — — (3,500 ) (3,500 ) $ 102,003 $ 120,784 $ 156,498 $ 379,285 n/a – not applicable Acquisitions in 2017 In connection with the acquisition of Novae, the Company identified finite lived intangible assets of $385 million , including Value of Business Acquired ("VOBA") which represents the present value of the expected underwriting profit within policies that were in-force at the closing date of the transaction, of $257 million and other finite lived intangible assets primarily related to distribution networks of $128 million . In addition, the Company identified indefinite lived intangible assets related to Lloyd's syndicate capacity of $95 million . The Company also recognized goodwill of $54 million . In connection with the acquisition of Contessa, the Company recognized goodwill of $1 million . Intangible Assets with an Indefinite Life Intangible assets with an indefinite life include U.S. state licenses that provide a legal right to transact business indefinitely and the value of Lloyd's syndicate capacity, which represents Novae's right to underwrite a certain allocated limit of premium in the Lloyd's market. Impairment Review The Company's impairment review of goodwill and indefinite lived intangibles resulted in the recognition of an impairment loss of $4 million for the year ended December 31, 2018 , related to the termination of the MGA contract intangible asset identified in connection with the acquisition of Novae. The Company's impairment reviews of goodwill and indefinite lived intangibles did not result in the recognition of impairment losses for the years ended December 31, 2017 and 2016 . The tables below provide details of the gross amount and accumulated amortization by category of VOBA and intangible assets: VOBA and intangible assets Balance At December 31, 2018 Gross amount Accumulated amortization and impairment Total U.S. state licenses $ 26,036 n/a $ 26,036 Customer lists, trademark and non-compete - Media Pro 9,700 (9,598 ) 102 Customer relationships and customers lists - Ternian 13,330 (4,999 ) 8,331 VOBA - Aviabel 2,140 (2,140 ) — VOBA - Novae 256,942 (221,228 ) 35,714 Syndicate capacity 94,748 n/a 94,748 Coverholders 63,565 (6,622 ) 56,943 Large brokers 46,641 (3,888 ) 42,753 SME brokers 14,126 (1,471 ) 12,655 MGA contract (1) 4,131 (4,131 ) — $ 531,359 $ (254,077 ) $ 277,282 (1) During the year ended December 31, 2018, an impairment charge of $3,500 was recognized related to the termination of the MGA contract intangible asset identified in connection with the acquisition of Novae. VOBA and Intangible assets Balance At December 31, 2017 Gross amount Accumulated amortization Total U.S. state licenses $ 26,036 n/a $ 26,036 Customer lists, trademark and non-compete - Media Pro 9,700 (9,244 ) 456 Customer relationships and customers lists - Ternian 13,330 (3,666 ) 9,664 VOBA - Aviabel 2,140 (977 ) 1,163 VOBA - Novae 256,942 (50,104 ) 206,838 Syndicate capacity 94,748 n/a 94,748 Coverholders 63,565 (1,324 ) 62,241 Large brokers 46,641 (777 ) 45,864 SME brokers 14,126 (294 ) 13,832 MGA contract 4,131 (148 ) 3,983 $ 531,359 $ (66,534 ) $ 464,825 The table below provides details of estimated amortization expense of VOBA and intangible assets with a finite life: VOBA Intangible assets Total 2019 26,722 11,017 37,739 2020 5,139 10,916 16,055 2021 3,853 10,916 14,769 2022 — 10,916 10,916 2023 — 10,916 10,916 2024 and thereafter — 66,103 66,103 Total remaining amortization expense 35,714 120,784 156,498 Indefinite lived intangible assets — 120,784 120,784 Total intangible assets $ 35,714 $ 241,568 $ 277,282 The estimated remaining useful lives of finite lived intangible assets range from 1 to 14 years.

INVESTMENTS

INVESTMENTS	12 Months Ended
	Dec. 31, 2018
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 Gross Gross Fair Non-credit (5) 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 ) At December 31, 2017 Fixed maturities U.S. government and agency $ 1,727,643 $ 1,735 $ (16,909 ) $ 1,712,469 $ — Non-U.S. government 798,582 17,240 (9,523 ) 806,299 — Corporate debt 5,265,795 61,922 (29,851 ) 5,297,866 — Agency RMBS (1) 2,414,720 8,132 (27,700 ) 2,395,152 — CMBS (2) 776,715 4,138 (3,125 ) 777,728 — Non-Agency RMBS 45,713 1,917 (799 ) 46,831 (853 ) ABS (3) 1,432,884 5,391 (1,994 ) 1,436,281 — Municipals (4) 149,167 1,185 (972 ) 149,380 — Total fixed maturities $ 12,611,219 $ 101,660 $ (90,873 ) $ 12,622,006 $ (853 ) (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 Gross Fair 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 At December 31, 2017 Equity securities Common stocks $ 22,836 $ 3,412 $ (590 ) $ 25,658 Exchange-traded funds 356,252 71,675 (294 ) 427,633 Bond mutual funds 173,779 9,440 (999 ) 182,220 Total equity securities $ 552,867 $ 84,527 $ (1,883 ) $ 635,511 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 6(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 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 % At December 31, 2017 Maturity Due in one year or less $ 486,659 $ 484,663 3.8 % Due after one year through five years 4,906,207 4,912,189 38.9 % Due after five years through ten years 2,338,964 2,350,433 18.6 % Due after ten years 209,357 218,729 1.7 % 7,941,187 7,966,014 63.0 % Agency RMBS 2,414,720 2,395,152 19.0 % CMBS 776,715 777,728 6.2 % Non-Agency RMBS 45,713 46,831 0.4 % ABS 1,432,884 1,436,281 11.4 % Total $ 12,611,219 $ 12,622,006 100.0 % 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 December 31, 2018 (1) 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 ) At December 31, 2017 Fixed maturities U.S. government and agency $ 194,916 $ (5,963 ) $ 1,389,792 $ (10,946 ) $ 1,584,708 $ (16,909 ) Non-U.S. government 62,878 (6,806 ) 204,110 (2,717 ) 266,988 (9,523 ) Corporate debt 407,300 (11,800 ) 2,041,845 (18,051 ) 2,449,145 (29,851 ) Agency RMBS 759,255 (17,453 ) 1,172,313 (10,247 ) 1,931,568 (27,700 ) CMBS 31,607 (703 ) 348,943 (2,422 ) 380,550 (3,125 ) Non-Agency RMBS 8,029 (788 ) 4,197 (11 ) 12,226 (799 ) ABS 57,298 (570 ) 392,170 (1,424 ) 449,468 (1,994 ) Municipals 11,230 (269 ) 65,632 (703 ) 76,862 (972 ) Total fixed maturities $ 1,532,513 $ (44,352 ) $ 5,619,002 $ (46,521 ) $ 7,151,515 $ (90,873 ) Equity securities Common stocks $ — $ — $ 3,202 $ (590 ) $ 3,202 $ (590 ) Exchange-traded funds — — 12,323 (294 ) 12,323 (294 ) Bond mutual funds — — 12,184 (999 ) 12,184 (999 ) Total equity securities $ — $ — $ 27,709 $ (1,883 ) $ 27,709 $ (1,883 ) (1) Effective January 1, 2018, the Company adopted ASU No. 2016-01, which requires equity securities to be measured at fair value with changes in fair value recognized in net income therefore equity securities at fair value are excluded from the table above at December 31, 2018. Fixed Maturities At December 31, 2018 , 3,599 fixed maturities ( 2017 : 2,424 ) were in an unrealized loss position of $215 million ( 2017 : $91 million ) of which $49 million ( 2017 : $7 million ) was related to securities below investment grade or not rated. At December 31, 2018 , 1,656 fixed maturities ( 2017 : 627 ) had been in a continuous unrealized loss position for twelve months or greater and had a fair value of $3,570 million ( 2017 : $1,533 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 December 31, 2018 , and were expected to recover in value as the securities approach maturity. At December 31, 2018 , 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: December 31, 2018 December 31, 2017 Carrying value % of Total Carrying value % of Total Mortgage Loans held-for-investment: Commercial $ 298,650 100 % $ 325,062 100 % Total Mortgage Loans held-for-investment $ 298,650 100 % $ 325,062 100 % 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 December 31, 2018 and 2017 , there were 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 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 % At December 31, 2017 Long/short equity funds $ 38,470 4 % Annually 60 days Multi-strategy funds 286,164 28 % Quarterly, Semi-annually 60-95 days Event-driven funds 39,177 4 % Annually 45 days Direct lending funds 250,681 25 % n/a n/a Private equity funds 68,812 7 % n/a n/a Real estate funds 50,009 5 % n/a n/a CLO-Equities 31,413 2 % n/a n/a Other privately held investments 46,430 5 % n/a n/a Overseas deposits 198,217 20 % n/a n/a Total other investments $ 1,009,373 100 % 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 2018 and 2017 , neither of these restrictions impacted the Company's redemption requests. At December 31, 2018 , $27 million ( 2017 : $38 million ), representing 14% ( 2017 : 11% ) of total hedge funds, relate to holdings where the Company is still within the lockup period. The expiration of these lockup periods range from March 2019 to March 2021. At December 31, 2018 , the Company had $210 million ( 2017 : $137 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 December 31, 2018 , the Company had $84 million ( 2017 : $16 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 December 31, 2018 , the Company had $147 million ( 2017 : $115 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 December 31, 2018 , the Company had $16 million ( 2017 : $21 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 December 31, 2018 , 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. Given that the Company exercises significant influence over the operating and financial policies of this investee, 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. For the year ended December 31, 2017 , the Company recorded an impairment charge of $9 million , related to a U.S. based insurance company, which reduced the carrying value of the investment to $ nil . This charge was included in interest in income (loss) of equity method investments in the consolidated statement of operations. e) Net Investment Income Net investment income was derived from the following sources: Year ended December 31, 2018 2017 2016 Fixed maturities $ 356,273 $ 312,662 $ 305,459 Other investments 48,959 76,858 42,514 Equity securities 10,077 14,919 16,306 Mortgage loans 13,566 10,780 7,996 Cash and cash equivalents 27,566 10,057 9,209 Short-term investments 9,365 2,718 2,060 Gross investment income 465,806 427,994 383,544 Investment expenses (27,299 ) (27,189 ) (30,209 ) Net investment income $ 438,507 $ 400,805 $ 353,335 f) Net Investment Gains (Losses) The following table provides an analysis of net investment gains (losses): Year ended December 31, 2018 2017 2016 Gross realized investment gains Fixed maturities and short-term investments $ 46,067 $ 72,046 $ 86,267 Equity securities 20,435 78,343 19,104 Gross realized investment gains 66,502 150,389 105,371 Gross realized investment losses Fixed maturities and short-term investments (142,153 ) (98,442 ) (134,460 ) Equity securities (3,389 ) (959 ) (16,155 ) Gross realized investment losses (145,542 ) (99,401 ) (150,615 ) Net OTTI charge recognized in net income (9,733 ) (14,493 ) (26,210 ) Change in fair value of investment derivatives (1) 5,445 (8,269 ) 10,929 Change in fair value of equity securities (2) (66,890 ) — — Net investment gains (losses) $ (150,218 ) $ 28,226 $ (60,525 ) (1) Refer to Note 8 'Derivative Instruments' (2) Effective January 1, 2018, the Company adopted ASU No. 2016-01. The change in fair value of equity securities is now recognized in net income. The following table summarizes the OTTI charge recognized in net income by asset class: Year ended December 31, 2018 2017 2016 Fixed maturities: Non-U.S. government $ 4,697 $ 8,187 $ 3,557 Corporate debt 4,995 6,306 20,093 Non-Agency CMBS 41 — — 9,733 14,493 23,650 Equity Securities Exchange-traded funds — — 2,560 — — 2,560 Total OTTI recognized in net income $ 9,733 $ 14,493 $ 26,210 Fixed Maturities The following table provides a roll forward of credit losses ("credit loss table") before income taxes, for which a component of the OTTI charge was recognized in AOCI: Year ended December 31, 2018 2017 Balance at beginning of period $ 1,494 $ 1,493 Credit impairments recognized on securities not previously impaired — — Additional credit impairments recognized on securities previously impaired 8 13 Change in timing of future cash flows on securities previously impaired — — Intent to sell of securities previously impaired — — Securities sold/redeemed/matured (992 ) (12 ) Balance at end of period $ 510 $ 1,494 The credit loss component of an OTTI charge recognized in net income is calculated based on the difference between the amortized cost of the security and the net present value of its projected future cash flows discounted at the effective interest rate implicit in the debt security prior to the impairment. A summary of credit loss activities by asset class as well as the significant inputs and the methodology used to estimate these credit losses are described below. U.S. Government, U.S. Agency and U.S. Agency RMBS: Unrealized losses on securities issued or backed (either explicitly or implicitly) by the U.S. government are not analyzed for OTTI. The Company has concluded that the possibility of a credit losses on these securities is highly unlikely due to the explicit U.S. government guarantee on certain securities (e.g. GNMA issuances) and the implicit guarantee on other securities that has been validated by past actions (e.g. U.S. government bailout of FNMA and FHLMC during the 2008 credit crisis). Although these securities are not analyzed for credit losses, they are still evaluated for intention to sell and likely requirement to sell. Non-U.S. Government: Non-U.S. government securities are evaluated for credit losses primarily through qualitative assessment of the likelihood of credit losses using information such as duration and severity of unrealized losses, as well as credit ratings and price volatility. At December 31, 2018 , the Company's holdings in sovereign debt, including $29 million ( 2017 : $185 million ) relating to the eurozone countries, were substantially all investment-grade securities. At December 31, 2018 , the gross unrealized investment losses of $16 million were mainly due to foreign exchange losses. Based on analysis performed, the Company does not anticipate any credit losses on non-U.S. government fixed maturities held at December 31, 2018 . In 2018 , the OTTI charge on non-U.S. government fixed maturities mainly related to unrealized foreign exchange losses on certain securities where forecasted recovery was uncertain. Corporate Debt: To estimate credit losses for corporate debt securities, the company's projected cash flows are primarily driven by assumptions regarding the probability of default and the severity associated with those defaults. The company's default and loss severity rates are based on credit rating, credit analysis, industry analyst reports and forecasts, Moody’s historical default data and any other data relevant to the recoverability of the security. In 2018 , the OTTI charge on corporate debt securities mainly related to significant loss severity, unrealized foreign exchange losses on certain securities where forecasted recovery was uncertain, as well as the Company's intent to sell. CMBS: The Company's investments in CMBS are diversified and primarily rated AA or better. At December 31, 2018 , CMBS had a weighted average estimated subordination percentage of 31% ( 2017 : 29% ). Based on discounted cash flows at December 31, 2018 , the current level of subordination is sufficient to cover the estimated loan losses on the underlying collateral of the CMBS. Non-agency RMBS: For non-agency RMBS, the Company's projected cash flows incorporated underlying data from widely accepted third-party data sources along with certain internal assumptions and judgments regarding the future performance of the security. These assumptions included default, delinquency, loss severity and prepayment rates. The assumptions used to calculate the credit losses in 2018 have not changed significantly since December 31, 2017 . At December 31, 2018 , the fair value of the Company's non-agency RMBS was $41 million ( 2017 : $47 million ), consisting primarily of $31 million ( 2017 : $34 million ) of Prime and $5 million ( 2017 : $8 million ) of Alt-A MBS. At December 31, 2018 , the Company concluded that there are no credit losses anticipated for any of its non-agency RMBS other than those already recorded. ABS: The Company's investments in ABS at December 31, 2018 consist mainly of CLO debt tranched securities ("CLO Debt") purchased primarily as new issues during 2017 through 2018. Substantially all of these new issues had credit ratings of AA or better. The Company utilizes a scenario-based approach to reviewing its CLO Debt portfolio based on the current asset market price. The Company also reviews subordination levels of these securities to determine their ability to absorb credit losses of underlying collateral. If losses are forecast to be below the subordination level for a tranche held by the Company, the security is determined not to be impaired. At December 31, 2018 , the Company concluded that there are no credit losses anticipated for any of its CLO Debt. g) Restricted Assets In order to support the Company's obligations in regulatory jurisdictions where it operates as a non-admitted carrier, the Company provides collateral in the form of assets held in trust and, to a lesser extent, letters of credit (refer to Note 11(c) ' Debt and Financing Arrangement s'). In addition, the Company operates in the Lloyd’s market through its corporate member AXIS Corporate Capital UK Limited, which represents its participation in Syndicate 1686 and Novae Corporate Underwriting Limited, the sole corporate member of Syndicate 2007. Lloyd’s sets capital requirements for corporate members annually through the application of a capital model that is based on regulatory rules pursuant to Directive 2009/138/EC of the European Parliament and of the Council of 25 November 2009 on the taking up and pursuit of business of Insurance and Reinsurance (Solvency II) ("Solvency II"). The capital provided to support underwriting, or Funds at Lloyd’s ("FAL"), may be satisfied by cash, certain investments and letters of credit provided by approved banks (refer to Note 12 'Commitments and Contingencies' and Note 20 ' Statutory Financial Information' ). At December 31, 2018 collateral in trust for third party agreements included $403 million ( 2017 : $1,120 million ) of fixed maturities and equity securities, and cash of $39 million ( 2017 : $55 million ) held on deposit to support the underwriting activities of Syndicate 2007. At December 31, 2018 collateral in trust for third party agreements included cash of $154 million ( 2017 : $140 million ) held on deposit to support the underwriting activities of Syndicate 1686. The Company's restricted investments and cash primarily consist of high-quality fixed maturity and short-term investment securities. The fair value of the Company's restricted investments and cash primarily relates to these items, as noted in the table below. At December 31, 2018 2017 Collateral in Trust for inter-company agreements $ 2,121,522 $ 3,310,180 Collateral for secured letter of credit facility 470,051 386,451 Funds at Lloyd's 1,307,945 1,192,717 Collateral in Trust for third party agreements 1,510,416 2,085,443 Securities on deposit with regulatory authorities 64,360 53,925 Total restricted investments $ 5,474,294 $ 7,028,716 h) Reverse Repurchase Agreements At December 31, 2018 , the Company held $189 million ( 2017 : $37 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	12 Months Ended
	Dec. 31, 2018
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. In 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. In 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 with redemptions based on the net asset values per share ("NAV") of the funds, 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 Significant other observable 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 8) — 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 8) $ — $ 4,223 $ 10,299 $ — $ 14,522 Cash settled awards (refer to Note 16) — 20,648 — — 20,648 Total Liabilities $ — $ 24,871 $ 10,299 $ — $ 35,170 (1) Includes Long/short equity, Multi-strategy and Event-driven funds. Quoted prices in active markets Significant other observable Significant unobservable inputs (Level 3) Fair value based on NAV practical expedient Total fair value At December 31, 2017 Assets Fixed maturities U.S. government and agency $ 1,658,622 $ 53,847 $ — $ — $ 1,712,469 Non-U.S. government — 806,299 — — 806,299 Corporate debt — 5,244,969 52,897 — 5,297,866 Agency RMBS — 2,395,152 — — 2,395,152 CMBS — 777,728 — — 777,728 Non-Agency RMBS — 46,831 — — 46,831 ABS — 1,436,281 — — 1,436,281 Municipals — 149,380 — — 149,380 1,658,622 10,910,487 52,897 — 12,622,006 Equity securities Common stocks 25,658 — — — 25,658 Exchange-traded funds 427,633 — — — 427,633 Bond mutual funds — 182,220 — — 182,220 453,291 182,220 — — 635,511 Other investments Hedge funds (1) — — — 363,811 363,811 Direct lending funds — — — 250,681 250,681 Private equity funds — — — 68,812 68,812 Real estate funds — — — 50,009 50,009 Other privately held investments — — 46,430 — 46,430 CLO-Equities — — 31,413 — 31,413 Overseas deposits — 198,217 — — 198,217 — 198,217 77,843 733,313 1,009,373 Short-term investments — 83,661 — — 83,661 Other assets Derivative instruments (refer to Note 8) — 5,125 — — 5,125 Insurance-linked securities — — 25,090 — 25,090 Total Assets $ 2,111,913 $ 11,379,710 $ 155,830 $ 733,313 $ 14,380,766 Liabilities Derivative instruments (refer to Note 8) $ — $ 2,876 $ 11,510 $ — $ 14,386 Cash settled awards (refer to Note 16) — 21,535 — — 21,535 Total Liabilities $ — $ 24,411 $ 11,510 $ — $ 35,921 (1) Includes Long/short equity, Multi-strategy and Event-driven funds. During 2018 and 2017 , the Company had no transfers between Levels 1 and 2. The following table quantifies the significant unobservable inputs used in estimating fair values at December 31, 2018 of investments classified as Level 3 in the fair value hierarchy. Fair value Valuation technique Unobservable input Range Weighted average Other investments - CLO-Equities $ 21,271 Discounted cash flow Default rates 3.0% 3.0% Loss severity rate 35% 35% Collateral spreads 3.0% 3.0% Estimated maturity dates 7 years 7 years Other investments - Other privately held investments $ 44,518 Discounted cash flow Discount rate 3.0% - 8.0% 7.1% Derivatives - Other underwriting-related derivatives $ (10,299 ) Discounted cash flow Discount rate 2.6% 2.6% 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-Equity 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 table presents 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) Year ended December 31, 2018 Fixed maturities Corporate debt $ 52,897 $ 2,935 $ (4,279 ) $ (591 ) $ 6,343 $ 10,267 $ (7,446 ) $ (11,114 ) $ 49,012 $ — CMBS — 5,096 — — (145 ) 17,200 — (3,017 ) 19,134 — ABS — 1,979 — — (446 ) 17,000 — — 18,533 — 52,897 10,010 (4,279 ) (591 ) 5,752 44,467 (7,446 ) (14,131 ) 86,679 — Other investments Other privately held investments 46,430 — — (913 ) — 3,110 (4,109 ) — 44,518 (913 ) CLO-Equities 31,413 — — 6,627 — — — (16,769 ) 21,271 6,627 77,843 — — 5,714 — 3,110 (4,109 ) (16,769 ) 65,789 5,714 Other assets Derivative instruments — — — — — — — — — — Insurance-linked securities 25,090 — — (90 ) — — — (25,000 ) — — 25,090 — — (90 ) — — — (25,000 ) — — Total assets $ 155,830 $ 10,010 $ (4,279 ) $ 5,033 $ 5,752 $ 47,577 $ (11,555 ) $ (55,900 ) $ 152,468 $ 5,714 Other liabilities Derivative instruments 11,510 — — (1,211 ) — — — — 10,299 (1,211 ) Total liabilities $ 11,510 $ — $ — $ (1,211 ) $ — $ — $ — $ — $ 10,299 $ (1,211 ) Year ended December 31, 2017 Fixed maturities Corporate debt $ 75,875 $ 2,324 $ (2,721 ) $ (503 ) $ (1,524 ) $ 17,062 $ (22,903 ) $ (14,713 ) $ 52,897 $ — CMBS 3,061 — — — — — — (3,061 ) — — ABS 17,464 — (18,949 ) — 1,485 — — — — — 96,400 2,324 (21,670 ) (503 ) (39 ) 17,062 (22,903 ) (17,774 ) 52,897 — Other investments Other privately held investments 42,142 — — 1,584 — 2,704 — — 46,430 1,584 CLO-Equities 60,700 — — 2,558 — — — (31,845 ) 31,413 2,558 102,842 — — 4,142 — 2,704 — (31,845 ) 77,843 4,142 Other assets Derivative instruments 2,532 — — 653 — — — (3,185 ) — — Insurance-linked securities 25,023 — — 67 — — — — 25,090 67 27,555 — — 720 — — — (3,185 ) 25,090 67 Total assets $ 226,797 $ 2,324 $ (21,670 ) $ 4,359 $ (39 ) $ 19,766 $ (22,903 ) $ (52,804 ) $ 155,830 $ 4,209 Other liabilities Derivative instruments 6,500 — — 9,320 — 12,472 — (16,782 ) 11,510 (962 ) Total liabilities $ 6,500 $ — $ — $ 9,320 $ — $ 12,472 $ — $ (16,782 ) $ 11,510 $ (962 ) (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. The transfers into and out of fair value hierarchy levels reflect the fair values of the securities at the end of the reporting period. Transfers into Level 3 from Level 2 The transfers into Level 3 from Level 2 made during 2018 and 2017 were primarily due to the lack of observable market inputs and multiple quotes from pricing vendors and broker-dealers for certain fixed maturities. Transfers out of Level 3 into Level 2 The transfers out of Level 3 into Level 2 made during 2018 and 2017 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. In 2018, funds reported on a lag represented 61% ( 2017 : 44% ) 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 December 31, 2018 , 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 December 31, 2018 , 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 December 31, 2018 , senior notes are recorded at amortized cost with a carrying value of $1,342 million ( 2017 : $1,341 million ) and a fair value of $1,334 million ( 2017 : $1,412 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. During the year ended December 31, 2018 , the Company redeemed its notes payable at par. At December 31, 2017 , notes payable were recorded at amortized cost with a carrying value of $36 million and a fair value of $36 million . The fair values of the notes payable were primarily determined by estimating expected future cash flows and discounting them using current interest rates for notes payable with similar credit risk. As notes payable were not actively traded their fair values were classified as Level 3.

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	12 Months Ended
	Dec. 31, 2018
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. At December 31, 2018 At December 31, 2017 Derivative notional amount Asset derivative fair value (1) Liability derivative fair value (1) Derivative notional amount Asset derivative fair value (1) Liability derivative fair value (1) Relating to investment portfolio: Foreign exchange forward contracts $ 79,336 $ 262 $ 531 $ 137,422 $ 10 $ 619 Interest rate swaps 150,000 — 1,116 191,000 448 1,556 Relating to underwriting portfolio: Foreign exchange forward contracts 737,419 7,975 2,576 698,959 4,667 701 Other underwriting-related contracts 85,000 — 10,299 85,000 — 11,510 Total derivatives $ 8,237 $ 14,522 $ 5,125 $ 14,386 (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. December 31, 2018 December 31, 2017 Gross amounts Gross amounts offset Net amounts (1) Gross amounts Gross amounts offset Net amounts (1) Derivative assets $ 11,967 $ (3,730 ) $ 8,237 $ 8,178 $ (3,053 ) $ 5,125 Derivative liabilities $ 18,252 $ (3,730 ) $ 14,522 $ 17,439 $ (3,053 ) $ 14,386 (1) Net asset and liability derivatives are classified within other assets and other liabilities on the consolidated balance sheets. Refer to Note 6 '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 exchange 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. Weather Risk During 2013, the Company began to write derivative-based risk management products designed to address weather risks with the objective of generating profits on a portfolio basis. The majority of this business consisted of receiving a payment at contract inception in exchange for bearing the risk of variations in a quantifiable weather-related phenomenon, such as temperature. Where a client wished to minimize the upfront payment, these transactions were structured as swaps or collars. In general, the Company's portfolio of such derivative contracts was of short duration, with contracts being predominantly seasonal in nature. In order to economically hedge a portion of this portfolio, the Company also purchased weather derivatives. Effective July 1, 2017, the Company no longer writes derivative-based risk management products which address weather risks. Commodity Risk Within the Company's (re)insurance portfolio it is exposed to commodity price risk. The Company may hedge a portion of this price risk by entering into commodity derivative contracts. 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 income on derivative Amount of gain (loss) recognized in income on derivative 2018 2017 2016 Relating to investment portfolio: Foreign exchange forward contracts Net investment gains (losses) $ 3,446 $ (6,935 ) $ 10,929 Interest rate swaps Net investment gains (losses) 1,999 (1,334 ) — Relating to underwriting portfolio: Foreign exchange forward contracts Foreign exchange gains (losses) (3,509 ) 25,383 (8,179 ) Weather-related contracts Other insurance related income (losses) — (9,629 ) 4,910 Commodity contracts Other insurance related income (losses) — — (2,382 ) Other underwriting-related contracts Other insurance related income (losses) 2,384 1,476 — Total $ 4,320 $ 8,961 $ 5,278

RESERVE FOR LOSSES AND LOSS EXP

RESERVE FOR LOSSES AND LOSS EXPENSES	12 Months Ended
	Dec. 31, 2018
Insurance Loss Reserves [Abstract]
RESERVE FOR LOSSES AND LOSS EXPENSES	Reserving Methodology Sources of Information The Company's reserving process begins with the collection and analysis of paid and incurred claim data for each of the Company's segments. The segmental data is disaggregated by reserve class and further disaggregated by underwriting year and accident year. Underwriting year information is used to analyze the Company's business and subsequently allocate reserves to the respective accident years. Reserve classes are selected to ensure that the underlying contracts have homogeneous loss development characteristics, while remaining large enough to make the estimation of trends credible. The Company's reserve classes are reviewed on a regular basis and adjusted over time as the Company's business evolves. The paid and incurred claim data, in addition to industry benchmarks, serves as a key input to many of the methods employed by the Company's actuaries. The relative weights assigned to the Company's own historical loss data versus industry data vary according to the length of the development profile for the reserve class being evaluated ( refer to 'Net Incurred and Paid Claims Development Tables By Accident Year' below for further details by reserve class). The tables below map the Company's lines 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 Actuarial Analysis Multiple actuarial methods are available to estimate ultimate losses. Each method has its own assumptions and its own advantages and disadvantages, with no single estimation method being better than the others in all situations and no one set of assumption variables being meaningful for all reserve classes. The relative strengths and weaknesses of the particular estimation methods when applied to a particular group of claims can also change over time. The following is a brief description of the reserve estimation methods commonly employed by the Company's actuaries including a discussion of their particular strengths and weaknesses: • Expected Loss Ratio Method ("ELR Method") : This method estimates ultimate losses for an accident year or underwriting year by applying an expected loss ratio to the earned or written premium for that year. Generally, expected loss ratios are based on one or more of (a) an analysis of historical loss experience to date, (b) pricing information and (c) industry data, adjusted as appropriate, to reflect changes in rates and terms and conditions. This method is insensitive to actual incurred losses for the accident year or underwriting year in question and is, therefore, often useful in the early stages of development when very few losses have been incurred. Conversely, the lack of sensitivity to incurred/paid losses for the accident year or underwriting year in question means that this method is usually inappropriate in later stages of an accident year or underwriting year’s development. • Loss Development Method (also referred to as the "Chain Ladder Method" or "Link Ratio Method") : This method assumes that the losses incurred/paid for each accident year or underwriting year at a particular development stage follow a relatively similar pattern. It assumes that on average, every accident year or underwriting year will display the same percentage of ultimate losses incurred/paid at the same point in time after the inception of that year. The percentages incurred/paid are established for each development stage (e.g. 12 months, 24 months, etc.) after examining historical averages from historical loss development data and/or external industry benchmark information. Ultimate losses are then estimated by multiplying the actual incurred/paid losses by the reciprocal of the established incurred/paid percentage. The strengths of this method are that it reacts to loss emergence/payments and that it makes full use of historical claim emergence/payment experience. However, this method has weaknesses when the underlying assumption of stable loss development/payment patterns is not valid. This could be the consequence of changes in business mix, claim inflation trends or claim reporting practices and/or the presence of large claims, among other things. Furthermore, this method tends to produce volatile estimates of ultimate losses where there is volatility in the underlying incurred/paid patterns. In particular, where the expected percentage of incurred/paid losses is low, small deviations between actual and expected claims can lead to very volatile estimates of ultimate losses. As a result, this method is often unsuitable at early development stages for an accident year or underwriting year. • Bornhuetter-Ferguson Method ("BF Method") : This method can be seen as a combination of the ELR and Loss Development Methods, under which the Loss Development Method is given progressively more weight as an accident year or underwriting year matures. The main advantage of the BF Method is that it provides a more stable estimate of ultimate losses than the Loss Development Method at earlier stages of development, while remaining more sensitive to emerging loss development than the ELR Method. In addition, the BF Method allows for the incorporation of external market information through the use of expected loss ratios, whereas the Loss Development Method does not incorporate such information. As part of the loss reserve review process, the Company's actuaries employ the estimation method(s) that they believe will produce the most reliable estimate of ultimate losses, at that particular evaluation date, for each reserve class and accident year or underwriting year combination. Often, this is a blend (i.e. weighted average) of the results of two or more appropriate actuarial methods. These ultimate loss estimates are generally utilized to evaluate the adequacy of ultimate loss estimates for previous accident or underwriting years, established in the prior reporting period. For the initial estimate of the current accident or underwriting year, the available claim data is typically insufficient to produce a reliable estimate of ultimate losses. As a result, initial estimates for an accident or underwriting year are generally based on the ELR Method for longer tailed lines and a BF Method for shorter tailed lines. The initial ELR for each reserve class is established collaboratively by actuaries, underwriters and management at the start of the year as part of the planning process, taking into consideration prior accident years’ or underwriting years' experience and industry benchmarks, adjusted after considering factors such as exposure trends, rate differences, changes in contract terms and conditions, business mix changes and other known differences between the current year and prior accident or underwriting years. The initial expected loss ratios for a given accident or underwriting year may be modified over time if the underlying assumptions, such as loss development or premium rate changes, differ from the original assumptions. Key Actuarial Assumptions The use of the above actuarial methods requires the Company to make certain explicit assumptions, the most significant of which are: (1) expected loss ratios and (2) loss development patterns. In earlier years, significant reliance was placed on industry benchmarks in establishing expected loss ratios and selecting loss development patterns. Over time, more reliance has been placed on historical loss experience in establishing these ratios and selecting these patterns where the Company believes the weight of its own actual experience has become sufficiently credible for consideration. The weight given to the Company's experience differs for each of the three claim tail classes. In establishing expected loss ratios for the insurance segment, consideration is given to a number of other factors, including exposure trends, rate adequacy on new and renewal business, ceded reinsurance costs, changes in claims emergence and underwriters’ view of terms and conditions in the market environment. For the reinsurance segment, expected loss ratios are based on a contract-by-contract review, which considers information provided by clients together with estimates provided by underwriters and actuaries about the impact of changes in pricing, terms and conditions and coverage. Market experience of some classes of business as compiled and analyzed by an independent actuarial firm has also been considered, as appropriate. Claim Tail Analysis Short-tail Business Short-tail business generally includes exposures for which losses are usually known and paid within a relatively short period of time after the underlying loss event has occurred. The key actuarial assumptions for short-tail business in early accident years were primarily developed with reference to industry benchmarks for expected loss ratios and loss development patterns. As the Company's own historical loss experience amassed, it gained credibility and became relevant for consideration in establishing these key actuarial assumptions. As a result, the Company gradually increased the weighting assigned to its own historical experience in selecting the expected loss ratios and loss development patterns utilized to establish estimates of ultimate losses for an accident year. Due to the relatively short reporting and settlement patterns for short-tail business, more weight is generally placed upon experience-based methods and other qualitative considerations in establishing reserves for recent and more mature accident years. The majority of development for an accident year or underwriting year is expected to be recognized in the subsequent one to three years. Medium-tail Business Medium-tail business generally has claim reporting and settlement periods longer than those of short-tail reserve classes. For the Company's earliest accident and underwriting years, initial key actuarial expected loss ratio and loss development assumptions were established utilizing industry benchmarks. Due to the longer claim tail, the length of time required to develop its own credible loss history for use in the reserve process is greater for medium-tail business than for short-tail business. As a result, the number of years where the Company has relied heavily on industry benchmarks to establish its key actuarial assumptions is greater for medium-tail business. Long-tail Business In contrast to short and medium-tail business, the claim tail for long-tail business is expected to be notably longer, as claims are often reported and ultimately paid or settled years, or even decades, after the related loss events occur. As a general rule, estimates of accident year or underwriting year ultimate losses for long-tail business are notably more uncertain than those for short and medium-tail business. To date, key actuarial assumptions for long-tail business have been derived extensively from industry benchmarks supplemented with the Company's own historical experience. Given the Company's relatively short operating history in comparison to the development tail for this business, the Company does not believe that its own historical loss development for long-tail business has amassed an appropriate volume to serve as a fully credible input into the key actuarial assumptions previously outlined. While industry benchmarks that the Company believes reflect the nature and coverage of its business are considered, actual loss experience may differ from the benchmarks based on industry averages. Due to the length of the development tail for this business, reserve estimates for most accident years and underwriting years are predominantly based on the BF Method or ELR Method and the consideration of qualitative factors. Reserving for Significant Catastrophic Events The Company cannot estimate losses from widespread catastrophic events, such as hurricanes and earthquakes, using the traditional actuarial methods described above. Loss reserves for such events are estimated by management after a catastrophe occurs by completing an in-depth analysis of individual contracts which may potentially have been impacted by the catastrophic event. This in-depth analysis may rely on several sources of information including: • estimates of the size of insured industry losses from the catastrophic event and the Company's corresponding market share; • a review of portfolio of contracts performed to identify those contracts which may be exposed to the catastrophic event; • a review of modeled loss estimates based on information previously reported by customers and brokers, including exposure data obtained during the underwriting process; • discussions of the impact of the event with customers and brokers; and • catastrophe bulletins published by various independent statistical reporting agencies. A blend of these information sources is generally used to arrive at aggregate estimates of the ultimate losses arising from the catastrophic event. In subsequent reporting periods, changes in paid and incurred losses in relation to each significant catastrophe are reviewed and adjustments are made to estimates of ultimate losses for each event if there are developments that are different from previous expectations. Adjustments are recorded in the period in which they are identified. Selection of Reported Reserves – Management’s Best Estimate The Company's reserving process involves the collaboration of underwriting, claims, actuarial, legal, ceded reinsurance and finance departments, includes various segmental committee meetings and culminates with the approval of a single point best estimate by the Company's Group Reserving Committee, which comprises senior management. In selecting this best estimate, management considers actuarial estimates and applies informed judgment regarding qualitative factors that may not be fully captured in these actuarial estimates. Such factors include, but are not limited to; the timing of the emergence of claims, volume and complexity of claims, social and judicial trends, potential severity of individual claims and the extent of internal historical loss data versus industry information. While these qualitative factors are considered in arriving at the point estimate, no specific provisions for qualitative factors are established. With regard to establishing the fair value of reserves for losses and loss expenses for Novae at the acquisition date, weight was given to the observable value of these reserves based on the RITC transaction which was completed prior to the allocation of purchase price. Management made no change to the initial estimate when establishing its best estimate of reserves for losses and loss expenses at December 31, 2017. This is consistent with the Company's general approach of recognizing all or part of the anticipated cost of third party liability commutations if the transaction has either completed or is considered sufficiently likely to be completed in the near term. Reserve for Losses and Loss Expenses Reserve for losses and loss expenses comprise the following: As of December 31, 2018 2017 Reserve for reported losses and loss expenses $ 4,626,204 $ 5,137,659 Reserve for losses incurred but not reported 7,654,565 7,859,894 Reserve for losses and loss expenses $ 12,280,769 $ 12,997,553 Reserve Roll-forward The table below provides a reconciliation of beginning and ending net reserves for unpaid losses and loss expenses for the years indicated: Year ended December 31, 2018 2017 2016 Gross reserve for losses and loss expenses, beginning of year $ 12,997,553 $ 9,697,827 $ 9,646,285 Less reinsurance recoverable on unpaid losses, beginning of year (3,159,514 ) (2,276,109 ) (2,031,309 ) Net reserve for unpaid losses and loss expenses, beginning of year 9,838,039 7,421,718 7,614,976 Net incurred losses and loss expenses related to: Current year 3,389,949 3,487,826 2,496,574 Prior years (199,662 ) (200,054 ) (292,377 ) 3,190,287 3,287,772 2,204,197 Net paid losses and loss expenses related to: Current year (724,199 ) (703,796 ) (428,153 ) Prior years (2,368,615 ) (1,880,882 ) (1,763,696 ) (3,092,814 ) (2,584,678 ) (2,191,849 ) Foreign exchange and other (1,156,412 ) 1,713,227 (205,606 ) Net reserve for unpaid losses and loss expenses, end of year 8,779,100 9,838,039 7,421,718 Reinsurance recoverable on unpaid losses, end of year 3,501,669 3,159,514 2,276,109 Gross reserve for losses and loss expenses, end of year $ 12,280,769 $ 12,997,553 $ 9,697,827 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 2018 , 2017 and 2016 , the Company recognized net losses and loss expenses, net of reinstatement premiums, of $430 million , $835 million and $204 million , respectively, attributable to catastrophe and weather-related events. On April 16, 2018, the Company entered into a quota share retrocessional agreement with Harrington Re, a related party, which was deemed to have met the established criteria for retroactive reinsurance accounting. The Company recognized reinsurance recoverable on unpaid losses of $108 million related to this reinsurance agreement. This transaction was conducted at market rates consistent with negotiated arms-length contracts. On January 1, 2018, AXIS Managing Agency Ltd., 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 December 31, 2018 , foreign exchange and other included a reduction in reserves for losses and loss expenses of $819 million related to this transaction. On October 2, 2017, the Company acquired 100% ownership interest in Novae. At December 31, 2017, foreign exchange and other included reserves for losses and loss expenses of $2,126 million and reinsurance recoverables on unpaid and paid losses of $788 million related to this acquisition. On April 1, 2017, the Company acquired 100% ownership interest in Aviabel. At December 31, 2017, foreign exchange and other included reserves for losses and loss expenses of $79 million and reinsurance recoverables on unpaid and paid losses of $5 million related to this acquisition. The transfer of the insurance business of AXIS Specialty Australia to a reinsurer was approved by the Irish High Court on February 1, 2017 and the Federal Court of Australia of February 10, 2017. Consequently, the insurance policies, assets and liabilities of AXIS Specialty Australia were transferred to the reinsurer with effect from February 13, 2017. This resulted in the reduction of reserves for losses and loss expenses by $223 million and a reduction in reinsurance recoverables on unpaid and paid losses by $223 million . During April 2016, the Company entered into a quota share and adverse development cover reinsurance agreement, a retroactive contract which was deemed to have met the established criteria for retroactive reinsurance accounting. At December 31, 2016, foreign exchange and other included reinsurance recoverables of $150 million related to this reinsurance agreement. Prior Year Reserve Development 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 prior year reserve development by segment: Insurance Reinsurance Total Year ended December 31, 2018 $ 92,806 $ 106,856 $ 199,662 Year ended December 31, 2017 60,459 139,595 200,054 Year ended December 31, 2016 48,978 243,399 292,377 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. These reserve classes contributed $86 million of net favorable prior year reserve development in 2018 reflecting the recognition of overall better than expected loss emergence related to the 2017 catastrophe events. These reserve classes contributed $60 million and $148 million of net favorable prior year reserve development in 2017 and 2016 , respectively, reflecting the recognition of better than expected loss emergence. Medium-tail Business Medium-tail business consists primarily of the insurance and reinsurance professional reserve classes, the insurance credit and political risk reserve class and the reinsurance credit and surety reserve class. For the year ended December 31, 2018 , the reinsurance professional reserve class recognized net favorable prior year development of $21 million ( 2017 : $44 million , 2016 : $30 million ). For the year ended December 31, 2018 , the insurance professional reserve class recognized net favorable prior year development of $32 million ( 2017 : $26 million , 2016 : $14 million ). The net favorable prior year loss development on these reserve classes continued to reflect the generally favorable experience on older accident years as the Company continued to transition to more experienced based methods. For the year ended December 31, 2018 , the reinsurance credit and surety reserve class recorded net favorable prior year reserve development of $33 million ( 2017 : $33 million , 2016 : $10 million ). The net favorable prior year reserve development was due to the recognition of generally better than expected loss emergence. Long-tail Business Long-tail business consists primarily of the insurance and reinsurance liability reserve classes and the reinsurance motor reserve class. For the year ended December 31, 2018 , the reinsurance liability reserve classes contributed net favorable prior year development of $23 million ( 2017 : $43 million , 2016 : $44 million ). For the year ended December 31, 2018 , the net favorable prior year development was due to progressively increased weight given by management to experience based indications on older accident years. For the years ended December 31, 2017 and 2016 , the net favorable prior year development was primarily due to progressively increased weight given by management to experience based indications on older accident years, which have generally been favorable. For the year ended December 31, 2018 , the insurance liability reserve class recorded net adverse prior year development of $22 million ( 2017 : $8 million , 2016 : $8 million ). The net adverse prior year reserve development on the insurance liability reserve class in 2018 was primarily related to reserve strengthening within the Company's U.S. excess casualty book of business. The net adverse prior year reserve development in 2017 and 2016 was primarily attributable to reserve strengthening within the Company's run-off Bermuda excess casualty book of business. For the year ended December 31, 2018 , the reinsurance motor reserve class contributed net favorable prior year reserve development of $23 million ( 2017 : $1 million 2016 : $55 million ). The net favorable prior year reserve development on the motor reserve class in 2018 was primarily attributable to U.K. non proportional treaty business on older accident years. The net favorable prior year development in 2017 was adversely impacted by the decrease in the discount rate used to calculate lump sum awards in U.K. bodily injury cases, known as the Ogden Rate, which changed from plus 2.5% to minus 0.75% effective March 20, 2017. The net favorable prior year reserve development on the motor reserve class in 2016 related to favorable loss emergence trends on several classes of business spanning multiple accident years. At December 31, 2018 , net reserve for losses and loss expenses includes estimated amounts for numerous catastrophe events. The magnitude and/or complexity of losses arising from these events, in particular the California Wildfires and Hurricanes Michael and Florence which occurred in 2018 as well as Hurricanes Harvey, Irma and Maria, and the two earthquakes in Mexico which occurred in 2017, inherently increase the level of uncertainty and, therefore, the level of management judgment involved in arriving at estimated net reserves for losses and loss expenses. As a result, actual losses for these events may ultimately differ materially from current estimates. Net Incurred and Paid Claims Development Tables by Accident Year The following tables present net incurred and paid claims development by accident year, total incurred-but-not-reported liabilities plus expected development on reported claims, cumulative reported claims frequency and claims duration for each reserve class. The loss development tables are presented on an accident year basis for the insurance and reinsurance segments. The Company does not discount unpaid losses and loss expense reserves. Non-U.S. dollar denominated loss data is converted to U.S. dollar at the rates of exchange in effect at the balance sheet date for material underlying currencies. Fluctuations in foreign currency exchange rates may cause material shifts in loss development. Reserves for losses and loss expenses disclosed in the consolidated balance sheets are also revalued using the exchange rate at the balance sheet date. At December 31, 2018, the Company included Novae and Aviabel business in the relevant loss development tables retrospectively from the date of acquisition. With regard to Novae, the Company entered into an agreement for the RITC of the 2015 and prior years of account of Syndicate 2007 on January 1, 2018. This agreement was accounted for as a novation reinsurance contract which resulted in a reduction in reserves for losses and loss expenses of $819 million . Consequently, the retrospective treatment for the acquisition of Novae was adopted at December 31, 2018 as the data necessary to produce the loss development tables by accident year was available. With regard to Aviabel, the retrospective treatment for the acquisition was also adopted at December 31, 2018 as the data necessary to produce the loss development tables by accident year was available. To the extent that the Company enters into a disposition, the effects of the disposition are reported on a retrospective basis by removing the balances associated with the disposed of business. There are many considerations in establishing loss reserves and an attempt to evaluate loss reserves using solely the data presented in these tables could be misleading. The Company cautions against mechanical application of standard actuarial methodologies to project ultimate losses using data presented in this disclosure. Insurance Segment The reporting of cumulative claims frequency for the reserve classes within the insurance segment has been measured by counting the number of unique claim references including claim references assigned to nil and nominal case reserves. Claim references are grouped by claimant by loss event for each reserve class. For certain insurance facilities and business produced by managing general agents where underlying data is reported to the Company in an aggregated format, the information necessary to provide cumulative claims frequency is not available therefore reporting of claims frequency is deemed to be impracticable. Insurance Property and Other This reserve class includes property, terrorism, accident and health, and discontinued lines - Novae. The property line of business provides physical loss or damage, business interruption and machinery breakdown cover for virtually all types of property, including commercial buildings, residential premises, construction projects and onshore energy installations. This line of business includes primary and excess risks, some of which are catastrophe-exposed. The terrorism line of business provides cover for physical damage and business interruption of an insured following an act of terrorism and includes kidnap and ransom, and crisis management insurance. The accident and health line of business includes accidental death, travel insurance and specialty health products for employer and affinity groups. The accident and health line of business contributed net premiums earned of $208 million to this reserve class for the year ended December 31, 2018. A large increase in reported claims related to this line of business was observed from 2012. In particular, an increase in limited benefits medical business written in 2017 has resulted in a significant increase in reported claims observed in that year. The discontinued lines - Novae includes the international direct and facultative property line of business that Novae exited or placed into run-off in the fourth quarter of 2016. In general, reporting and payment patterns are relatively short-tailed although they can be volatile due to the incidence of catastrophe events. Insurance property and other Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected development on reported claims Cumulative number of reported claims Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 117,309 $ 99,079 $ 89,768 $ 82,460 $ 80,461 $ 78,269 $ 78,490 $ 78,150 $ 78,395 $ 77,338 $ 83 3,201 2010 175,012 155,032 147,426 122,111 116,562 115,635 115,316 114,866 113,767 867 4,422 2011 359,132 338,220 306,114 285,745 282,755 281,405 281,866 279,996 979 6,348 2012 391,646 399,473 381,746 361,476 357,267 351,673 350,827 8,992 29,931 2013 308,359 297,713 271,157 267,022 266,727 276,940 6,687 53,172 2014 360,130 354,219 343,333 327,389 326,100 5,917 62,444 2015 277,332 268,897 257,927 253,729 5,642 47,052 2016 349,152 376,458 367,362 12,290 92,867 2017 882,968 825,176 42,188 663,914 2018 712,082 187,391 730,832 Total $ 3,583,317 Insurance property and other Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance For the years ended December 31, Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 31,360 $ 60,085 $ 68,653 $ 72,499 $ 73,387 $ 74,453 $ 76,673 $ 76,980 $ 77,248 $ 77,252 2010 48,575 86,886 94,912 105,719 109,933 110,008 109,794 109,837 110,171 2011 84,811 192,892 249,162 271,451 270,309 269,994 270,666 270,946 2012 77,088 213,138 277,230 300,129 307,639 312,818 312,894 2013 75,214 197,898 236,405 247,393 258,435 261,266 2014 131,991 258,098 304,609 311,730 315,797 2015 98,366 201,166 225,593 239,989 2016 122,407 287,049 327,706 2017 251,358 625,027 2018 276,472 Total 2,817,520 All outstanding liabilities before 2009, net of reinsurance 5,862 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 771,659 Insurance property and other Average annual percentage payout of incurred claims by age, net of reinsurance (unaudited) Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 34.5% 40.2% 13.2% 5.8% 2.0% 0.8% 0.7% 0.2% 0.3% —% Insurance Marine This reserve class includes the marine line of business which provides cover for traditional marine classes, including offshore energy, cargo, liability, recreational marine, fine art, specie, and hull and war. Offshore energy coverage includes physical damage, business interruption, operators extra expense and liability coverage for all aspects of offshore upstream energy, from exploration and construction through the operation and distribution phases. The complex nature of claims arising under marine policies tends to result in reporting and payment patterns that are longer than those of the property and other class. Exposure to natural perils such as windstorm and earthquake can result in volatility. Insurance marine Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected developm

REINSURANCE

REINSURANCE	12 Months Ended
	Dec. 31, 2018
Reinsurance Disclosures [Abstract]
REINSURANCE	In the normal course of business, the Company purchases treaty and facultative reinsurance protection to limit its ultimate losses from catastrophic events and reduce its loss aggregation risk. Facultative reinsurance provides cover for all or a portion of the losses incurred for a single policy and the Company separately negotiates each facultative contract. Treaty reinsurance provides cover for a specified type or category of risks. The Company's treaty reinsurance agreements provide this cover on either an excess of loss or a proportional basis. Excess of loss covers provide a contractually set amount of coverage after a specified loss amount has been reached. These treaties can provide cover for a number of lines of business within one contract. Under proportional reinsurance, the Company cedes an agreed proportion of the premiums and the losses and loss expenses on the policies it underwrites. These treaties provide us with a specified percentage of coverage from the first dollar of loss. All of these reinsurance covers provide the Company the right to recover a portion of specified losses and loss expenses from reinsurers. However, to the extent that reinsurers do not meet their obligations under these agreements due to solvency issues, contractual disputes or other reasons, the Company remains liable. The Company predominantly cedes its business to reinsurers rated A- or better by internationally recognized rating agencies. Gross and net premiums written and earned were as follows: Year ended December 31, 2018 2017 2016 Premiums written Premiums earned Premiums written Premiums earned Premiums written Premiums earned Gross $ 6,910,065 $ 6,882,217 $ 5,556,273 $ 5,616,234 $ 4,970,208 $ 4,762,394 Ceded (2,251,103 ) (2,090,722 ) (1,529,130 ) (1,467,474 ) (1,217,234 ) (1,056,769 ) Net $ 4,658,962 $ 4,791,495 $ 4,027,143 $ 4,148,760 $ 3,752,974 $ 3,705,625 For the year ended December 31, 2018 , the Company recognized ceded losses and loss expenses of $1,565 million ( 2017 : $1,010 million ; 2016 : $556 million ). At December 31, 2018 , the Company's provision for uncollectible amounts was $21 million ( 2017 : $17 million ; 2016 : $20 million ).

DEBT AND FINANCING ARRANGEMENTS

DEBT AND FINANCING ARRANGEMENTS	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
DEBT AND FINANCING ARRANGEMENTS	a) Senior Notes and Notes Payable On March 23, 2010, AXIS Specialty Finance LLC, a 100% owned finance subsidiary, issued $500 million aggregate principal amount of 5.875% senior unsecured debt (the '' 5.875% Senior Notes'') at an issue price of 99.624% . The net proceeds of the issuance, after consideration of the offering discount and underwriting expenses and commissions, totaled approximately $495 million . Interest on the 5.875% Senior Notes is payable semi-annually in arrears on June 1 and December 1 of each year, beginning on June 1, 2010. Unless previously redeemed, the 5.875% Senior Notes will mature on June 1, 2020. The 5.875% Senior Notes are ranked as unsecured senior obligations of AXIS Specialty Finance LLC. AXIS Capital has fully and unconditionally guaranteed all obligations of AXIS Specialty Finance LLC under the 5.875% Senior Notes. AXIS Capital’s obligations under this guarantee are unsecured senior obligations and rank equally with all other senior obligations of AXIS Capital. On March 13, 2014, AXIS Specialty Finance PLC, a 100% owned finance subsidiary, issued $ 250 million aggregate principal amount of 2.65% senior unsecured notes (the " 2.65% Senior Notes") at an issue price of 99.896% and $ 250 million aggregate principal amount of 5.15% senior unsecured notes (the " 5.15% Senior Notes", and, together with the 5.875% Senior Notes and the 2.65% Senior Notes, the "Senior Notes") at an issue price of 99.474% . The net proceeds of the issuance, after consideration of the offering discount and underwriting expenses and commissions, totaled approximately $ 248 million and $ 246 million for the 2.65% Senior Notes and the 5.15% Senior Notes, respectively. Interest on the 2.65% Senior Notes and the 5.15% Senior Notes is payable semi-annually in arrears on April 1 and October 1 of each year, beginning on October 1, 2014. Unless previously redeemed, the 2.65% Senior Notes and the 5.15% Senior Notes will mature on April 1, 2019 and April 1, 2045, respectively. The 2.65% Senior Notes and the 5.15% Senior Notes are ranked as unsecured senior obligations of AXIS Specialty Finance PLC. AXIS Capital has fully and unconditionally guaranteed all obligations of AXIS Specialty Finance PLC under the 2.65% Senior Notes and the 5.15% Senior Notes. AXIS Capital's obligations under this guarantee are unsecured senior obligations and rank equally with all other senior obligations of AXIS Capital. On December 6, 2017 , AXIS Specialty Finance PLC, a 100% owned finance subsidiary, issued $350 million aggregate principal amount of 4.0% senior unsecured notes (the " 4.0% Senior Notes") at an issue price of 99.78% . The net proceeds of the issuance, after consideration of the offering discount and underwriting expenses and commissions, totaled approximately $ 347 million . Interest on the 4.0% Senior Notes is payable semi-annually in arrears on June 6 and December 6 of each year, beginning on June 6, 2018. Unless previously redeemed, the 4.0% Senior Notes will mature on December 6, 2027. The 4.0% Senior Notes are ranked as unsecured senior obligations of AXIS Specialty Finance PLC. AXIS Capital has fully and unconditionally guaranteed all obligations of AXIS Specialty Finance PLC under the 4.0% Senior Notes. AXIS Capital's obligations under this guarantee are unsecured senior obligations and rank equally with all other senior obligations of AXIS Capital. The Company has the option to redeem the Senior Notes at any time and from time to time, in whole or in part, at a ''make-whole'' redemption price, which is equal to the greater of the aggregate principal amount or the sum of the present values of the remaining scheduled payments of principal and interest. The related indentures contain various covenants, including limitations on liens on the stock of restricted subsidiaries, restrictions as to the disposition of the stock of restricted subsidiaries and limitations on mergers and consolidations. The Company was in compliance with all the covenants contained in the indentures at December 31, 2018 . Interest expense recognized in relation to Senior Notes includes interest payable, amortization of the offering discounts and amortization of debt offering expenses. The offering discounts and debt offering expenses are amortized over the period of time during which the Senior Notes are outstanding. For the year ended December 31, 2018 , the Company incurred interest expense of $64 million ( 2017 : $51 million , 2016 : $50 million ). b) Dekania Notes On June 30, 2004, Novae issued $15 million aggregate principal amount of LIBOR plus 3.50% subordinated unsecured notes (the " $15 million Dekania Notes") and $11 million aggregate principal amount of LIBOR plus 4.05% subordinated unsecured notes (the " $11 million Dekania Notes"). On September 29, 2004, Novae issued $10 million aggregate principal amount of LIBOR + 3.50% subordinated notes (the " $10 million Dekania Notes" and together with the " $15 million Dekania Notes" and the " $11 million Dekania Notes" the "Dekania Notes"). The net proceeds of the issuance, after consideration of the offering discount and underwriting expenses and commissions, totaled approximately $35 million . Interest on the Dekania Notes was payable quarterly in arrears on February 15, May 15, August 15 and November 15 of each year. On November 15, 2018, the Company fully redeemed the Dekania Notes at par. Interest expense recognized in relation to the Dekania Notes included interest payable, amortization of the offering discounts and amortization of debt offering expenses. The offering discounts and debt offering expenses were amortized over the period of time during which the Dekania Notes were outstanding. For the year ended December 31, 2018 , the Company incurred interest expense of $2 million (2017: $2 million ). Scheduled Debt Maturity The scheduled maturity of the Company's aggregate amount of its debt obligation on its consolidated balance sheet at December 31, 2018 is shown in the following table: Year ended December 31, 2019 $ 250,000 2020 500,000 2021 — 2022 — 2023 — After 2023 600,000 Unamortized discount and debt issuance expenses (8,039 ) Total senior notes and notes payable $ 1,341,961 c) Credit Facilities Credit Facility On March 26, 2013, AXIS Capital and certain of its subsidiaries entered into a $250 million credit facility (the "Credit Facility"), which was issued by a syndication of lenders pursuant to a Credit Agreement and other ancillary documents (together, the "Facility Documents") and expired in March 2017. At the request of the Company and subject to the satisfaction of certain conditions, the aggregate commitment available under the Credit Facility could be increased by up to $150 million . Under the terms of the Credit Facility, loans were available for general corporate purposes and letters of credit could have been issued in the ordinary course of business, with total usage not to exceed the aggregate commitment available. Interest on loans issued under the Credit Facility was payable based on underlying market rates at the time of loan issuance. While loans under the Credit Facility were unsecured, the Company had the option to issue letters of credit on a secured basis in order to reduce associated fees. Letters of credit issued under the Credit Facility were principally used to support the (re)insurance obligations of the Company's operating subsidiaries. Each of AXIS Capital, AXIS Specialty Finance LLC, AXIS Specialty Holdings Bermuda Limited and AXIS Specialty Finance PLC guaranteed the obligations of the other parties to the Credit Facility. The Credit Facility was subject to certain non-financial covenants, including limitations on fundamental changes, the incurrence of additional indebtedness and liens and certain transactions with affiliates and investments, as defined in the Facility Documents. The Credit Facility also required compliance with certain financial covenants, including a maximum debt to capital ratio and a minimum consolidated net worth requirement. In addition, each of AXIS Capital’s material (re)insurance subsidiaries party to the Credit Facility had to maintain a minimum A.M. Best financial strength rating. In the event of default, including a breach of these covenants, the lenders had the right to exercise certain remedies, including the termination of the Credit Facility, the declaration of all principal and interest amounts related to Credit Facility loans to be immediately due and the requirement that all outstanding letters of credit be collateralized. On September 18, 2013, the Credit Facility was amended in order to permit AXIS Capital and its subsidiaries to enter into swap contracts and other arrangements related to weather derivative transactions. All other material terms and conditions remained unchanged. Effective February 10, 2014, AXIS Specialty Finance PLC was added as a guarantor to the Credit Facility. On March 27, 2017, the Credit Facility expired. Letter of Credit Facility On November 20, 2013, certain of AXIS Capital’s operating subsidiaries (the "Participating Subsidiaries") entered into an amendment to extend the term of the Company's secured $750 million letter of credit facility (the "LOC Facility") with Citibank Europe plc ("Citibank") pursuant to a Master Reimbursement Agreement and other ancillary documents (together, the "LOC Facility Documents"). Under the terms of the LOC Facility, letters of credit to a maximum aggregate amount of $750 million are available for issuance on behalf of the Participating Subsidiaries. These letters of credit will principally be used to support the reinsurance obligations of the Participating Subsidiaries. The LOC Facility is subject to certain covenants, including the requirement to maintain sufficient collateral, as defined in the LOC Facility Documents, to cover all of the obligations under the LOC Facility. Such obligations include contingent reimbursement obligations for outstanding letters of credit and fees payable to Citibank. In the event of default, Citibank may exercise certain remedies, including the exercise of control over pledged collateral and the termination of the availability of the LOC Facility to any or all of the Participating Subsidiaries. On March 31, 2015, the Company entered into an amendment to reduce the maximum aggregate utilization capacity of the LOC Facility from $750 million to $500 million . All other material terms and conditions remained unchanged. On December 18, 2015, the Participating Subsidiaries renewed the $500 million secured LOC Facility with Citibank for a four year term commencing December 31, 2015, pursuant to certain updates to the LOC Facility Documents. All other material terms and conditions remained unchanged. On March 27, 2017, the Participating Subsidiaries amended their existing $500 million secured LOC Facility with Citibank to include an additional $250 million of secured letter of credit capacity (the " $250 Million Facility") pursuant to a Committed Facility Letter and an amendment to the Master Reimbursement Agreement. Under the terms of the $250 Million Facility, letters of credit to a maximum aggregate amount of $250 million are available for issuance on behalf of the Participating Subsidiaries. These letters of credit will principally be used to support the reinsurance obligations of the Participating Subsidiaries. The $250 Million Facility is subject to certain covenants, including the requirement to maintain sufficient collateral, as defined in the LOC Facility Documents, to cover all of the obligations under the LOC Facility. Such obligations include contingent reimbursement obligations for outstanding letters of credit and fees payable to the lender. In the event of default, the lender may exercise certain remedies, including the exercise of control over pledged collateral and the termination of the availability of the facility to any or all of the participating operating subsidiaries. On March 28, 2018, 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, 2019. The terms and conditions of the $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 the obligations outstanding under the $750 million Facility. In the event of default, Citibank 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. At December 31, 2018 , letters of credit outstanding under the LOC Facility totaled $395 million . At December 31, 2018 , the Company was in compliance with all LOC Facility covenants. Novae Syndicated Bank Facility On August 2, 2016, Novae entered into a syndicated bank financing facility, which provided the company with a combined letter of credit and revolving credit facility of $229 million and a term loan of $67 million . On December 29, 2017, the term loan was repaid and the letter of credit and revolving credit facility were terminated. For the year ended December 31, 2017, the Company recognized $1 million of interest expense in relation to the syndicated bank financing facility.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	a) Concentrations of Credit Risk Credit Risk Aggregation The Company monitors and manages the aggregation of credit risk on a group-wide basis allowing it to consider exposure management strategies for individual companies, countries, regions, sectors and any other relevant inter-dependencies. The Company's credit exposures are aggregated based on the origin of risk. As part of its credit aggregation framework, the Company also assigns aggregate credit limits by single counterparty (a group of companies or country). These limits are based on and adjusted for a variety of factors including the prevailing economic environment and the nature of the underlying credit exposures. The Company's credit aggregation measurement and reporting process is facilitated by its credit risk exposure database, which contains relevant information on counterparty details and credit risk exposures. The Company also licenses third party tools to provide credit risk assessments. Credit risk aggregation is also managed through minimizing overlaps in underwriting, financing and investing activities. The assets that potentially subject the Company to concentrations of credit risk consist principally of cash and investments, reinsurance recoverable on unpaid and paid claims and insurance and reinsurance premiums balances receivable, as described below: (i) Cash and Investments In order to mitigate concentration and operational risks related to cash and cash equivalents, the Company limits the maximum amount of cash that can be deposited with a single counterparty and limits acceptable counterparties based on current rating, outlook and other relevant factors. The Company's investment portfolio is managed by external investment managers in accordance with its investment guidelines. The Company limits credit risk through diversification, issuer exposure limits graded by ratings and, with respect to custodians, through contractual and other legal remedies. Excluding U.S. government and agency securities, the Company limits its concentration of credit risk to any single corporate issuer to 2% or less of its investment grade fixed maturities portfolio for securities rated A- or above and 1% or less of its investment grade fixed maturities portfolio for securities rated below A-. At December 31, 2018 , the Company was in compliance with these limits. (ii) Reinsurance Recoverable on Unpaid and Paid Losses The Company is exposed to the credit risk associated with reinsurance recoverable on unpaid and paid losses to the extent that any of its reinsurers fail to meet their obligations under reinsurance contracts. To help mitigate this risk, the Company's purchase of reinsurance is subject to financial security requirements specified by its Reinsurance Security Committee. This Committee maintains a list of approved reinsurers, performs credit risk assessments for potential new reinsurers, regularly monitors approved reinsurers with consideration for events which may have a material impact on their creditworthiness, recommends counterparty tolerance levels for different types of ceded business and monitors concentrations of credit risk. This assessment considers a wide range of individual attributes, including a review of the counterparty’s financial strength, industry position and other qualitative factors. Generally, the Committee requires that reinsurers who do not meet specified requirements provide collateral. At December 31, 2018 , the three largest balances by reinsurer accounted for 13% , 10% and 10% ( 2017 : 12% , 11% and 7% ) of reinsurance recoverable on unpaid and paid losses. At December 31, 2018 , 89.5% (December 31, 2017: 88.8% ) of the Company's reinsurance recoverable on unpaid and paid losses were collectible from reinsurers rated the equivalent of A- or better by internationally recognized rating agencies. (iii) Insurance and Reinsurance Premium Balances Receivable The diversity of the Company's client base limits the credit risk associated with its insurance and reinsurance premium balances receivable. In addition, for insurance contracts the Company has contractual rights to cancel cover for non-payment of premiums and for reinsurance contracts the Company has contractual rights to offset premium balances receivable against corresponding payments for losses and loss expenses. Brokers and other intermediaries collect premiums from customers on behalf of the Company. The Company has procedures in place to manage and monitor credit risk from intermediaries with a focus on day-to-day monitoring of the largest positions. These contractual rights contribute to the mitigation of credit risk, together with the monitoring of aged premium balances receivable. In light of these mitigating factors, and considering that a significant portion of premium balances receivable are not currently due based on the terms of the underlying contracts, the Company does not utilize specific credit quality indicators to monitor its premium balances receivable. At December 31, 2018 , the Company recorded an allowance for estimated uncollectible premium balances receivable of $4 million ( 2017 : $6 million ). For the year ended December 31, 2018 , bad debt expense was $ nil ( 2017 : $ nil ; 2016 : $1 million ). b) Brokers The Company produces its business through brokers and direct relationships with insurance companies. For the year ended December 31, 2018 , three brokers accounted for 43% ( 2017 : 49% ; 2016 : 52% ) of gross premiums written. Marsh & McLennan Companies Inc. accounted for 17% ( 2017 : 20% ; 2016 : 21% ), Aon plc accounted for 17% ( 2017 : 17% ; 2016 : 19% ), and Willis Tower Watson PLC accounted for 9% ( 2017 : 12% ; 2016 : 12% ). No other broker and no single insured or reinsured accounted for more than 10% of gross premiums written in any of the last three years. c) Lease Commitments In the ordinary course of business, the Company renews and enters into new leases for office space which expire at various dates. For the year ended December 31, 2018 , operating lease expense was $33 million ( 2017 : $29 million ; 2016 : $25 million ). Future minimum lease payments are 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 d) Reinsurance Purchase Commitment In the normal course of business, the Company purchases reinsurance and retrocessional (collectively referred to as "reinsurance") protection for its insurance and reinsurance lines of business. Minimum reinsurance premiums are contractually due in advance on a quarterly basis. At December 31, 2018 , the Company had outstanding reinsurance purchase commitments of $39 million , all of which is due before March 31, 2022. Actual payments under the reinsurance contracts will depend on the underlying subject premium and may exceed the minimum premium. e) 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 related to these proceedings are included in the reserve for losses and loss expenses in the Company's consolidated balance sheets. The Company is not party to any material legal proceedings arising outside the ordinary course of business. f) Investments At December 31, 2018 the Company has $ 507 million ( 2017 : $414 million ) of unfunded investment commitments related to its other investment portfolio, which are callable by investment managers (refer to Note 6(c) ' Investments '). At December 31, 2018 the Company has $4 million ( 2017 : $16 million ) of unfunded investment commitments to purchase commercial mortgage loans. g) Funds at Lloyd's The Company operates in the Lloyd’s market through its corporate member AXIS Corporate Capital UK Limited, which represents its participation in Syndicate 1686 and Novae Corporate Underwriting Limited, the sole corporate member of Syndicate 2007. Lloyd’s sets capital requirements for corporate members annually through the application of a capital model that is based on regulatory rules pursuant to Solvency II. The capital provided to support underwriting or FAL may be satisfied by cash, certain investments and letters of credit provided by approved banks. At December 31, 2018 , investments and cash of $1.3 billion ( 2017 : $1.2 billion ) were restricted to satisfy the Company's FAL requirements (refer to Note 6 'Investments' and Note 20 ' Statutory Financial Information' ).

EARNINGS PER COMMON SHARE

EARNINGS PER COMMON SHARE	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
EARNINGS PER COMMON SHARE	The following table presents a comparison of earnings (loss) per common share and earnings (loss) per diluted common share: At and year ended December 31, 2018 2017 2016 Earnings (loss) per common share Net income (loss) $ 43,021 $ (368,969 ) $ 513,368 Less: Preferred share dividends 42,625 46,810 46,597 Less: Loss on repurchase of preferred shares — — 1,309 Net income (loss) available (attributable) to common shareholders $ 396 $ (415,779 ) $ 465,462 Weighted average common shares outstanding 83,501 84,108 90,772 Earnings (loss) per common share $ — $ (4.94 ) $ 5.13 Earnings (loss) per diluted common share Net income (loss) available (attributable) to common shareholders $ 396 $ (415,779 ) $ 465,462 Weighted average common shares outstanding 83,501 84,108 90,772 Share-based compensation plans (1) 506 — 775 Weighted average diluted common shares outstanding (1) 84,007 84,108 91,547 Earnings (loss) per diluted common share $ — $ (4.94 ) $ 5.08 Weighted average anti-dilutive shares excluded from the dilutive computation 245 702 170 (1) Due to the net loss incurred in the year ended December 31, 2017, all the share equivalents were anti-dilutive.

SHAREHOLDERS' EQUITY

SHAREHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2018
Stockholders' Equity Note [Abstract]
SHAREHOLDERS' EQUITY	a) Common Shares The Company's authorized share capital is 800,000,000 common shares, par value of $0.0125 per share. The following table presents changes in common shares issued and outstanding, excluding restricted stock units related to the Company's share-based compensation plans (refer to Note 16 ' Share-Based Compensation' ): Year ended December 31, 2018 2017 2016 Shares issued, balance at beginning of year 176,580 176,580 176,240 Shares issued — — 340 Total shares issued at end of year 176,580 176,580 176,580 Treasury shares, balance at beginning of year (93,419 ) (90,139 ) (80,174 ) Shares repurchased (200 ) (4,288 ) (10,508 ) Shares reissued 625 1,008 543 Total treasury shares at end of year (92,994 ) (93,419 ) (90,139 ) Total shares outstanding 83,586 83,161 86,441 During 2018 , the total cash dividends declared per common share were $1.57 ( 2017 : $1.53 ; 2016 : $1.43 ). Treasury Shares On July 5, 2017, the Company and the board of directors of Novae announced that it had agreed on terms of a recommended offer to be made by the Company to acquire the entire issued and to be issued share capital of Novae. Following the offer, the Company suspended its open market share repurchase plan. On December 31, 2017, authorization under the Board-authorized share repurchase plan for common share repurchases through 2017 expired. A common share repurchase plan has not been authorized for 2018 or 2019. The following table presents common shares repurchased from shares held in treasury: Year ended December 31, 2018 2017 2016 In the open market: Total shares (1) — 3,932 10,241 Total cost $ — $ 261,180 $ 557,476 Average price per share (2) $ — $ 66.43 $ 54.44 From employees: (3) Total shares 200 356 267 Total cost $ 10,080 $ 24,678 $ 14,329 Average price per share (2) $ 50.40 $ 69.36 $ 53.74 Total shares repurchased: Total shares 200 4,288 10,508 Total cost $ 10,080 $ 285,858 $ 571,805 Average price per share (2) $ 50.40 $ 66.67 $ 54.42 (1) Amounts in 2016 include common shares acquired under the accelerated share repurchase program of 1,358,380 (see below for more detail). (2) Calculated using whole numbers. (3) Shares are repurchased from employees to satisfy withholding tax liabilities that arise upon the vesting of restricted stock awards and restricted stock units. Share repurchases from employees are excluded from the authorized share repurchase plan noted above. Accelerated Share Repurchase Program On August 17, 2015 , the Company entered into an Accelerated Share Repurchase ("ASR") agreement with Goldman, Sachs & Co. ("Goldman Sachs") to repurchase an aggregate of $300 million of the Company's ordinary shares under an accelerated share repurchase program. During August 2015 , under the terms of this agreement, the Company paid $300 million to Goldman Sachs and initially repurchased 4,149,378 common shares. The initial shares acquired represented 80% of the $300 million total paid to Goldman Sachs and were calculated using the Company’s stock price at the activation of the program. The ASR program was accounted for as an equity transaction. At December 31, 2015, $240 million of common shares repurchased were included as treasury shares in the consolidated balance sheets with the remaining $60 million included as a reduction to additional paid-in capital. On January 15, 2016 , Goldman Sachs early terminated the ASR agreement and delivered 1,358,380 additional common shares to the Company, resulting in the reclassification of $60 million from additional paid-in capital to treasury shares. In total, the Company repurchased 5,507,758 common shares under the ASR agreement at an average price of $54.47 . b) Preferred Shares Series B Preferred Shares On November 23, 2005, the Company issued $250 million of 7.50% Series B preferred shares, par value $0.0125 per share, with a liquidation preference of $100.00 per share. The Company could redeem the Series B preferred shares on or after December 1, 2015 at a redemption price of $100.00 per share. Dividends on the Series B preferred shares were non-cumulative. Holders of Series B preferred shares were entitled to receive, only when, as and if declared by the board of directors, non-cumulative cash dividends, from the original issue date, quarterly in arrears on the first day of March, June, September and December of each year, commencing on March 1, 2006, up to but not including January 27, 2016 . To the extent declared, these dividends accumulated, with respect to each dividend period, in an amount per share equal to 7.50% of the liquidation preference per annum. During April 2012, the Company closed a cash tender offer for any and all of the outstanding 7.50% Series B preferred shares at a purchase price of $102.81 per share. As a result, the Company purchased 2,471,570 Series B preferred shares for $254 million . In connection with this tender offer, a loss on redemption of $9 million was recognized in determining net income available to common shareholders. On January 27, 2016 the Company redeemed the remaining 28,430 Series B preferred shares, for an aggregate redemption price of $3 million . Series C Preferred Shares On March 19, 2012, the Company issued $400 million of 6.875% Series C preferred shares, par value $0.0125 per share, with a liquidation preference of $25.00 per share. The Company could redeem the Series C preferred shares on or after April 15, 2017 at a redemption price of $25.00 per share. Dividends on the Series C preferred shares were non-cumulative. Holders of the Series C preferred shares were entitled to receive, only when, as and if declared by the board of directors, non-cumulative cash dividends, from the original issue date, quarterly in arrears on the fifteenth day of January, April, July and October of each year, commencing on July 15, 2012. To the extent declared, these dividends accumulated, with respect to each dividend period, in an amount per share equal to 6.875% of the liquidation preference per annum. During October and November 2016, the Company repurchased 1,957,045 Series C preferred shares at an average purchase price of $25.67 per share for $50 million . In connection with the repurchase of these shares, a loss on redemption of $1 million , was recognized in determining net income available to common shareholders. On April 17, 2017, the Company redeemed the remaining 14,042,955 Series C preferred shares, for an aggregate liquidation preference of $351 million . In 2017 , the total dividends declared and paid on Series C preferred shares were $0.4297 per share. In 2016 , the total dividends declared and paid on Series C preferred shares were $1.7188 per share. Series D Preferred Shares On May 20, 2013, the Company issued $225 million of 5.50% Series D preferred shares, par value $0.0125 per share, with a liquidation preference of $25.00 per share. The Company may redeem the Series D preferred shares on or after June 1, 2018 at a redemption price of $25.00 per share. Dividends on the Series D preferred shares are non-cumulative. Holders of the Series D preferred shares will be entitled to receive, only when, as and if declared by the board of directors, non-cumulative cash dividends from the original issue date, quarterly in arrears on the first day of March, June, September and December of each year, commencing on September 1, 2013. To the extent declared, these dividends will accumulate, with respect to each dividend period, in an amount per share equal to 5.50% of the liquidation preference per annum. At December 31, 2018 , the Company had not redeemed any of the $225 million of 5.50% Series D preferred shares. In 2018 , total dividends declared on Series D preferred shares were $1.375 per share, of which $1.0313 was paid in 2018 and the remaining $0.34375 is payable in 2019. In 2017 , total dividends declared on Series D preferred shares were $1.3750 per share, of which $1.0313 was paid in 2017 and $0.3438 was paid in 2018. In 2016 , total dividends declared and paid on Series D preferred shares were $1.375 per share. Series E Preferred Shares On November 7, 2016, the Company issued $550 million of 5.50% Series E preferred shares, par value $0.0125 per share, with a liquidation preference of $2,500 per share. The Company may redeem the Series E preferred shares on or after November 7, 2021 at a redemption price of $2,500 per share. Dividends on the Series E preferred shares are non-cumulative. Holders of the Series E preferred shares will be entitled to receive, only when, as and if declared by the board of directors, non-cumulative cash dividends from the original issue date, quarterly in arrears on the fifteenth day of January, April, July and October of each year, commencing on January 15, 2017. To the extent declared, these dividends will accumulate, with respect to each dividend period, in an amount per Series E preferred share equal to 5.50% of the liquidation preference per annum. In 2018 , total dividends declared on Series E preferred shares were $137.5 per share of which, $103.13 was paid in 2018 and the remaining $34.375 was paid in 2019. In 2017 , total dividends declared and paid on Series E preferred shares were $137.5 per share of which, $103.13 was paid in 2017 and $34.375 was paid in 2018. In 2016 , total dividends declared on Series E preferred shares were $34.375 per share, which were subsequently paid in 2017 .

RETIREMENT PLANS

RETIREMENT PLANS	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
RETIREMENT PLANS	The Company maintains defined contribution plans to provide retirement benefits to eligible employees. Contributions to the plans, which are managed externally, are based on eligible compensation. For eligible U.S. employees, the Company provides a non-qualified deferred compensation plan that enables employees to make contributions to the plan that are in excess of those permitted under the Company's 401(k) Plan. In addition, employees are permitted to make additional contributions from any bonus received and to benefit from discretionary employer contribution to the Plan. During 2018 , total pension expenses were $27 million ( 2017 : $24 million and 2016 : $23 million ) for the above retirement benefits.

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
SHARE-BASED COMPENSATION	In May 2017, shareholders approved the establishment of the AXIS Capital Holdings Limited 2017 Long-Term Equity Compensation Plan (the "2017 Plan"). The 2017 Plan provides for, among other things, the issuance of restricted shares, restricted stock units (share-settled awards and cash-settled awards), performance units (share-settled awards and cash-settled awards), stock options, stock appreciation rights and other equity-based awards to the Company's employees and directors. The 2017 Plan authorizes the issuance of a total of 3,400,000 common shares. The Company's 2017 Plan replaced its 2007 Long-Term Equity Compensation Plan ("2007 Plan") upon expiration of the 2007 Plan in May 2017. All remaining shares available pursuant to the 2007 Plan have been canceled although awards made pursuant to the 2007 Plan prior to its expiration remain in effect in accordance with the terms of the 2007 Plan. At December 31, 2018 , 2,824,592 equity-based awards remained available for grant pursuant to the 2017 Plan. The grant date fair value of each award is established at the fair market value of the Company's common shares at the date of grant. Restricted Stock Awards Restricted stock awards ("RSAs") granted pursuant to the 2007 Plan generally vest in accordance with a four year graded vesting schedule in four annual installments beginning on the grant date. Share-Settled Restricted Stock Units Restricted stock units ("RSUs") granted pursuant to the 2017 Plan or the 2007 Plan either cliff vest at the end of a three year period, vest in accordance with a three year graded vesting schedule, or vest in accordance with a four year graded vesting schedule in four annual installments beginning on the grant date. Cash-Settled Restricted Stock Units Cash-settled restricted stock units ("Cash-settled RSUs") granted pursuant to the 2017 Plan or the 2007 Plan are liability awards and generally cliff vest at the end of a three year period, or vest in accordance with a four year graded vesting schedule in four annual installments beginning on the grant date. Performance-Vesting Restricted Stock Units Performance-vesting restricted stock units ("PSUs") granted pursuant to the 2017 Plan or the 2007 Plan, represent the right to receive a specified number of common shares in the future, based upon the achievement of established performance criteria and continued service during the applicable performance period. Awards granted pursuant to these plans generally cliff vest at the end of a three year period. Compensation expense is recognized on a straight-line basis over the applicable requisite service period and is subject to periodic adjustment based upon the achievement of established performance criteria during the applicable performance period. PSUs granted are either share-settled awards or cash-settled liability awards. Acceleration Provisions Grants provided under the 2017 Plan and the 2007 Plan generally allow for accelerated vesting provisions upon the employee’s death, permanent disability, or certain terminations following a change in control of the Company occurring within two years of the change in control event. Notwithstanding these vesting provisions, the Compensation Committee of our Board has broad authority to accelerate vesting at its own discretion. Retirement Plan In 2016, the Company established the AXIS Executive RSU Retirement Plan (the "Plan") to reward certain eligible long-term employees of the Company for their dedicated service. The Plan was implemented in 2017. Subject to certain conditions being met, eligible employees will not forfeit all of their outstanding RSUs or Cash-settled RSUs on or following their retirement. Absent the Plan, outstanding RSUs are generally forfeited upon termination of employment. a) Share-Settled Awards The following table provides an activity summary of the Company's share-settled RSUs: Share-Settled PSUs Share-Settled Service Based RSUs 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 - December 31, 2016 283 $ 51.27 1,593 $ 48.88 Granted 87 64.58 733 61.94 Vested (2) (119 ) 49.14 (889 ) 47.48 Forfeited (21 ) 55.00 (82 ) 54.89 Nonvested restricted stock - December 31, 2017 230 57.08 1,355 57.09 Granted 104 48.89 737 49.36 Vested (87 ) 54.71 (539 ) 54.51 Forfeited (15 ) 53.80 (142 ) 55.36 Nonvested restricted stock - December 31, 2018 232 $ 54.54 1,411 $ 54.12 (1) Fair value is based on the closing price of the Company's common shares on the grant date. (2) Share-settled restricted stock units that vested during the year ended December 31, 2017 included 313,391 service based restricted stock units which were granted in 2014 and were subject to a three year cliff vesting period. b) Cash-Settled Awards The following table provides an activity summary of the Company's cash-settled RSUs: Cash-Settled PSUs Cash-Settled Service based RSUs Number of restricted stock units Number of restricted stock units Nonvested restricted stock units - December 31, 2016 68 1,392 Granted 15 432 Vested (1) (38 ) (763 ) Forfeited (3 ) (73 ) Nonvested restricted stock units - December 31, 2017 42 988 Granted — 473 Vested (12 ) (390 ) Forfeited (3 ) (139 ) Nonvested restricted stock units - December 31, 2018 27 932 (1) Cash-settled restricted stock units that vested during the year ended December 31, 2017 included 307,556 service based restricted stock units which were granted in 2014 and were subject to a three year cliff vesting period. At December 31, 2018 , the liability for cash-settled restricted stock units, included in other liabilities in the consolidated balance sheets, was $21 million ( 2017 : $22 million ). During the year ended December 31, 2018 , the fair value of share-settled restricted stock units and cash-settled restricted stock units that vested was $51 million ( 2017 : $125 million , including $44 million attributable to service based restricted stock units which were granted in 2014 and were subject to a three year cliff vesting period; 2016 : $67 million ). At December 31, 2018 , there was $87 million ( 2017 : $94 million ) of unrecognized share-based compensation costs which are expected to be recognized over the weighted average period of 2.4 years ( 2017 : 2.5 years ). For the year ended December 31, 2018 the Company incurred share-based compensation costs of $54 million ( 2017 : $68 million ; 2016 : $74 million ) related to restricted stock awards, share-settled restricted stock units, and cash-settled restricted stock units. In addition, the Company recorded associated tax benefits of $8 million ( 2017 : $15 million ; 2016 : $16 million ).

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	A member of the Company’s Board of Directors, Mr. Charles Davis, is the Chief Executive Officer of Stone Point Capital, LLC ("Stone Point"). In the ordinary course of business, the Company engages SKY Harbor Capital Management, LLC, an affiliate of Stone Point, to provide asset management services for certain short duration high yield debt portfolios. For the year ended December 31, 2018 , total fees paid to SKY Harbor Capital Management, LLC, were $2 million ( 2017 : $2 million ; 2016 : $3 million ). The Company has invested $18 million in NXT Capital Senior Loan Fund II and $20 million in NXT Capital Senior Loan Fund III. The manager of these funds is an indirect subsidiary of NXT Capital Inc. ("NXT Capital"). Investment funds managed by Stone Point indirectly owned approximately 43% of NXT Capital until this ownership interest was sold in August 2018. For the year ended December 31, 2018 , fees paid to NXT Capital were $1 million ( 2017 : $1 million ; 2016: $1 million ). In addition, the Company has invested $50 million in the Freedom Consumer Credit Fund, LLC Series B. The manager of this fund is Freedom Financial Asset Management, LLC ("Freedom") which is an indirect subsidiary of Pantheon Partners, LLC ("Pantheon"). Investment funds managed by Stone Point own approximately 14.5% of Pantheon. For the year ended December 31, 2018 , fees paid to Freedom were $2 million ( 2017 : $1 million ). The Company's Chairman, Mr. Butt received consulting fees for the year ended December 31, 2018 of $0.5 million ( 2017 : $0.5 million ; 2016: $0.6 million ) pursuant to the terms of a consulting agreement by and between Mr. Butt and the Company dated May 3, 2012, as amended. The consulting agreement was further amended on December 5, 2018 to extend the term of the agreement to the Company's 2019 Annual General Meeting for an annual fee of $0.5 million . The Company's investment portfolio includes certain investments where it is considered to have the ability to exercise significant influence over the operating and financial policies of the investee. Significant influence is generally deemed to exist where the Company has an investment of 20% or more in the common stock of a corporation or an investment of 3% or more in closed end funds, limited partnerships, LLCs or similar investment vehicles. At December 31, 2018, the Company has $450 million ( 2017 : $451 million ) of investments where it is deemed to have the ability to exercise such significant influence. The Company generally pays management and performance fees to the investment managers of these investments. The Company considers all fees paid to the investment managers to be at market rates consistent with negotiated arms-length contracts. Harrington and Harrington Re commenced operations in 2016 (refer to Note 6 ' Investments '). AXIS Capital has the ability to exercise significant influence over the operating and financial policies of Harrington and Harrington Re. In the normal course of business, the Company entered into certain reinsurance transactions with Harrington Re. For the year ended December 31, 2018 , the Company ceded reinsurance premiums of $194 million ( 2017 : $213 million ) and ceded losses of $142 million ( 2017 : $119 million ) to Harrington Re. In addition, Harrington Re paid certain acquisition costs and administrative fees to the Company. At December 31, 2018 , the amount of reinsurance recoverable on unpaid and paid losses was $363 million ( 2017 : $152 million ) and the amount of ceded reinsurance payable included in insurance and reinsurance balances payable was $115 million ( 2017 : $142 million ) in the consolidated balance sheets. All transactions were conducted at market rates consistent with negotiated arms-length contracts. On November 5, 2013, the Company formed Ventures Re, a Bermuda domiciled insurer. With effect from January 1, 2015, Ventures Re is no longer consolidated in the financial statements of the Company. All of Ventures Re's directors are employees of the Company. In the normal course of business, the Company enters into certain reinsurance contracts with Ventures Re. For the year ended December 31, 2018 , the Company ceded premiums of $182 million ( 2017 : $107 million ) and ceded losses of $138 million ( 2017 : $126 million ) to Ventures Re. In addition, Ventures Re paid certain acquisition costs and administrative fees to the Company. At December 31, 2018 , the amount of reinsurance recoverable on unpaid and paid losses was $186 million ( 2017 : $131 million ) and the amount of ceded reinsurance payable included in insurance and reinsurance balances payable was $67 million ( 2017 : $17 million ) in the consolidated balance sheets. All transactions were conducted at market rates consistent with negotiated arms-length contracts.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	Under current Bermuda law, the Company's Bermuda domiciled subsidiaries are not required to pay any taxes in Bermuda on income or capital gains. The Company has received an assurance from the Minister of Finance in Bermuda that, in the event of any taxes being imposed, it will be exempt from taxation in Bermuda until March 2035. The Company's primary Bermuda subsidiary has an operating branch in Singapore, which is subject to the relevant taxes in that jurisdiction. The branch is not under examination in this tax jurisdiction, but remains subject to examination for tax years 2015 through 2018. The Company's U.S. subsidiaries are subject to federal, state and local corporate income taxes and other taxes applicable to U.S. corporations. The provision for federal income taxes has been determined under the principles of the consolidated tax provisions of the U.S. Internal Revenue Code and Regulations. Should the U.S. subsidiaries pay a dividend outside the U.S. group, withholding taxes will apply. The Company's U.S. subsidiaries are not under examination but remain subject to examination in the U.S. for tax years 2015 through 2018. In Canada, the Company's U.S. reinsurance company operates through a branch and its U.S. service company has an unlimited liability company subsidiary based in Canada. These Canadian operations are subject to the relevant taxes in that jurisdiction and remain subject to examination for tax years 2014 through 2018. The Company also has subsidiaries in Ireland, the U.K., Belgium, the Netherlands, Luxembourg, Brazil and Dubai. In 2017, the Company ceased operations in Australia. These subsidiaries and their branches, are not under examination, but remain subject to examination in all applicable jurisdictions for tax years 2014 through 2018. In the U.K., the Company has Lloyd’s syndicates whose income is subject to tax in the U.K. payable by its corporate members. The income from operations at Lloyd’s is also subject to taxes in other jurisdictions in which Lloyd's operates, including the U.S. Under a Closing Agreement between Lloyd’s and the IRS, Lloyd’s Members pay U.S. income tax on U.S. connected income written by Lloyd’s syndicates. To the extent that the Lloyd’s syndicates suffer taxes outside the U.K. they may claim a credit for foreign taxes suffered, limited to the U.K. equivalent tax on the same income. An analysis of income tax expense and net tax assets is shown in the following table: Year ended December 31, 2018 2017 2016 Current income tax expense (benefit) U.S. $ (5,401 ) $ (6,207 ) $ 606 Europe 10,409 10,249 7,451 Other 51 — — Deferred income tax expense (benefit) U.S. 15,288 18,495 (1,829 ) Europe (49,833 ) (30,079 ) 112 Total income tax expense (benefit) $ (29,486 ) $ (7,542 ) $ 6,340 Net current tax receivables (payables) $ 9,683 $ (639 ) $ 3,540 Net deferred tax assets 39,775 4,438 103,313 Net tax assets $ 49,458 $ 3,799 $ 106,853 Deferred income taxes reflect the tax impact of temporary differences between the carrying amounts of assets and liabilities for financial reporting and income tax purposes. The significant components of deferred tax assets and liabilities were as follows: At December 31, 2018 2017 Deferred tax assets: Discounting of net reserves for losses and loss expenses $ 37,440 $ 27,804 Unearned premiums 40,447 25,188 Net unrealized investments losses 11,438 — Operating and capital loss carryforwards (1) 83,850 53,095 Accruals not currently deductible 32,589 31,560 Tax credits 8,672 29,929 Other deferred tax assets 9,195 15,047 Deferred tax assets before valuation allowance 223,631 182,623 Valuation allowance (18,955 ) (16,157 ) Deferred tax assets net of valuation allowance 204,676 166,466 Deferred tax liabilities: Deferred acquisition costs (39,745 ) (24,249 ) Net unrealized investments gains — (8,033 ) Amortization of VOBA, intangible assets and goodwill (49,097 ) (85,296 ) Equalization reserves (22,069 ) (23,274 ) Other deferred tax liabilities (53,990 ) (21,176 ) Deferred tax liabilities (164,901 ) (162,028 ) Net deferred tax assets $ 39,775 $ 4,438 (1) At December 31, 2018 and 2017, the total operating loss carryforwards includes Lloyd's deferred year of account losses of $68 million and $19 million , respectively. On December 22, 2017, H.R.1, An Act to Provide for Reconciliation Pursuant to Titles II and V of the Concurrent Resolution on the Budget for Fiscal Year 2018 ("U.S. Tax Reform") was signed into law. U.S. Tax Reform, among other things, reduced the U.S. corporate income tax rate from 35% to 21% effective January 1, 2018. Consequently, the Company reduced its net deferred tax assets at December 31, 2017 by $41.6 million . As a result of the Company's acquisitions of Aviabel and Novae in 2017, $103.8 million of net deferred tax liabilities were acquired or established at the acquisition dates. Total operating and capital loss carryforwards and tax credits are summarized in the following table: At December 31, 2018 2017 Operating and Capital Loss Carryforwards (1) Singapore (branch) operating loss carryforward $ 79,445 $ 77,467 U.K. operating loss carryforward (2) 413,504 126,839 Ireland operating loss carryforward 12,756 — U.S. operating loss carryforward 15,062 115,236 Ireland capital loss carryforward 716 716 Tax Credits (1) Ireland foreign tax credit $ 2,248 $ 3,566 U.S. alternative minimum tax credit (3) 6,026 12,052 U.K. tax credit 398 14,310 (1) All operating and capital loss carryforwards and tax credits can be carried forward indefinitely with the exception of the U.S. net operating loss, which will expire in 2037. (2) At December 31, 2018 and 2017, the U.K. operating loss carryforward includes Lloyd's deferred year of account losses of $403 million and $113 million , respectively. (3) As a result of U.S. tax reform, all alternative minimum tax credits will be refunded by tax year 2021. An analysis of the movement in the Company's valuation allowance is shown in the following table: At December 31, 2018 2017 Income tax expense: Valuation allowance - beginning of year $ 16,157 $ 41,100 Operating loss carryforwards 198 (27,116 ) Foreign tax credit (1,359 ) 267 U.K. branch assets and other foreign rate differentials (205 ) 1,006 U.S. alternative minimum tax credits (900 ) 900 Valuation allowance - end of year $ 13,891 $ 16,157 Accumulated other comprehensive income: Valuation allowance - beginning of year — — Change in investment - related items 5,064 — Valuation allowance - end of year 5,064 — Total valuation allowance - end of year $ 18,955 $ 16,157 At December 31, 2018 and 2017 , the Company established a full valuation allowance on: (1) operating and capital loss carryforwards relating to operations in Singapore; (2) un-utilized foreign tax credits available in Ireland and (3) certain other deferred tax assets related to branch operations. At December 31, 2018 , the Company established a valuation allowance on certain unrealized investment losses. In 2017, the valuation allowance was released on the Australian operating loss carryforwards, capital loss carryforwards, and other deferred tax assets upon the cessation of operations. The valuation allowance was reduced by a net $1.2 million for items unrelated to the Australian operations. Although realization is not assured, management believes it is more likely than not that the tax benefit of the recorded net deferred tax assets will be realized. In evaluating the Company's ability to recover these tax assets within the jurisdiction from which they arise, it considered all available positive and negative evidence, including historical results, operating loss carry-back potential and scheduled reversals of deferred tax liabilities. The Company believes its U.S. and U.K. operations will produce significant taxable income in future periods and have deferred tax liabilities that will reverse in future periods, such that the Company believes sufficient ordinary taxable income is available to utilize all remaining ordinary deferred tax assets. At December 31, 2018 and 2017 , there were no unrecognized tax benefits. The following table presents the distribution of income before income taxes between domestic and foreign jurisdictions as well as a reconciliation of the actual income tax rate to the amount computed by applying the effective tax rate of 0% under Bermuda law to income before income taxes: Year ended December 31, 2018 2017 2016 Income (loss) before income taxes Bermuda (domestic) $ 181,597 $ (188,420 ) $ 469,306 Foreign (168,062 ) (188,091 ) 50,402 Total income before income taxes $ 13,535 $ (376,511 ) $ 519,708 Reconciliation of effective tax rate (% of income before income taxes) Expected tax rate 0.0 % 0.0 % 0.0 % Foreign taxes at local expected rates: U.S. 65.7 % 6.6 % (0.6 )% Europe (289.7 )% 5.8 % 1.5 % Other — % 0.3 % — % Valuation allowance (13.4 )% — % 0.2 % Net tax exempt income (3.3 )% 0.1 % (0.2 )% Change in U.S. enacted tax rate — % (11.1 )% — % Change in European enacted tax rate 16.9 % — % — % Other 5.9 % 0.3 % 0.3 % Actual tax rate (217.9 )% 2.0 % 1.2 %

OTHER COMPREHENSIVE INCOME (LOS

OTHER COMPREHENSIVE INCOME (LOSS)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
OTHER COMPREHENSIVE INCOME (LOSS)	The following table presents the tax effects allocated to each component of other comprehensive income (loss): Before tax amount Tax (expense) benefit Net of tax amount Year ended December 31, 2018 Available for sale investments: Unrealized investment gains (losses) arising during the year $ (297,259 ) $ 5,528 $ (291,731 ) Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income 105,730 (4,828 ) 100,902 Unrealized investment gains (losses) arising during the year, net of reclassification adjustment (1) (191,529 ) 700 (190,829 ) Non-credit portion of OTTI losses — — — Foreign currency translation adjustment (11,165 ) — (11,165 ) Total other comprehensive income (loss), net of tax $ (202,694 ) $ 700 $ (201,994 ) Year ended December 31, 2017 Available for sale investments: Unrealized investment gains (losses) arising during the year $ 211,151 $ (5,732 ) $ 205,419 Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income (33,892 ) 758 (33,134 ) Unrealized investment gains (losses) arising during the year, net of reclassification adjustment 177,259 (4,974 ) 172,285 Non-credit portion of OTTI losses — — — Foreign currency translation adjustment 41,938 — 41,938 Total other comprehensive income (loss), net of tax $ 219,197 $ (4,974 ) $ 214,223 Year ended December 31, 2016 Available for sale investments: Unrealized investment gains (losses) arising during the year $ 10,165 $ (5,093 ) $ 5,072 Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income 60,423 1,767 62,190 Unrealized investment gains (losses) arising during the year, net of reclassification adjustment 70,588 (3,326 ) 67,262 Non-credit portion of OTTI losses — — — Foreign currency translation adjustment (638 ) — (638 ) Total other comprehensive income (loss), net of tax $ 69,950 $ (3,326 ) $ 66,624 (1) Effective January 1, 2018, the Company adopted ASU No. 2016-01. The adoption of this guidance resulted in a cumulative adjustment to reclassify unrealized investment gains on equity securities from accumulated other comprehensive income to retained earnings. Refer to Item 8, Note 2 ' Basis of Presentation and Significant Accounting Policies ' to the consolidated financial statements for additional information. The following table presents reclassification amounts from accumulated other comprehensive income ("AOCI") to net income (loss) available (attributable) to common shareholders: Amount reclassified from AOCI (1) Details about AOCI components Consolidated statement of operations line item that includes reclassification Year ended December 31, 2018 2017 2016 Unrealized investment gains (losses) on available for sale investments Other realized investment gains (losses) $ (95,997 ) $ 48,385 $ (34,213 ) OTTI losses (9,733 ) (14,493 ) (26,210 ) Total before tax (105,730 ) 33,892 (60,423 ) Income tax (expense) benefit 4,828 (758 ) (1,767 ) Net of tax $ (100,902 ) $ 33,134 $ (62,190 ) Foreign currency translation adjustments Foreign exchange loss $ — $ (24,149 ) $ — Income tax (expense) benefit — — — Net of tax $ — $ (24,149 ) $ — (1) Amounts in parentheses are charges to net income (loss) available (attributable) to common shareholders On March 27, 2017, as part of the wind down of the Company's Australia operation, the Australia Prudential Regulation Authority revoked the authorization of AXIS Specialty Australia to carry on insurance business in Australia. As this resulted in the substantial liquidation of AXIS Specialty Australia, the Company released the cumulative translation adjustment related to AXIS Specialty Australia of $24 million from AOCI in the consolidation balance sheet to foreign exchange losses (gains) in the consolidated statement of operations.

STATUTORY FINANCIAL INFORMATION

STATUTORY FINANCIAL INFORMATION	12 Months Ended
	Dec. 31, 2018
STATUTORY FINANCIAL INFORMATION [Abstract]
STATUTORY FINANCIAL INFORMATION	The Company's insurance and reinsurance operations are subject to insurance and/or reinsurance laws and regulations in the jurisdictions in which they operate, the most significant of which include Bermuda, Ireland, the U.S. In addition, the Company is regulated by Lloyd's. These regulations include certain restrictions on the amount of dividends or other distributions, such as loans or cash advances, available to shareholders without prior approval of the insurance regulatory authorities. At December 31, 2018 and 2017 , the statutory capital and surplus in each of the Company's most significant regulatory jurisdictions are shown in the following table: Bermuda Ireland U.S. At December 31, 2018 2017 2018 2017 2018 2017 Required statutory capital and surplus $ 1,470,375 $ 1,800,064 $ 637,226 $ 613,923 $ 489,560 $ 488,560 Available statutory capital and surplus $ 3,513,342 $ 3,641,279 $ 896,868 $ 906,512 $ 1,668,847 $ 1,511,480 Bermuda Under the Insurance Act 1978, amendments thereto and Related Regulations of Bermuda (the "Act"), the Company's Bermuda subsidiary, AXIS Specialty Bermuda is required to maintain minimum statutory capital and surplus equal to the greater of a minimum solvency margin ("MSM") and the Enhanced Capital Requirement ("ECR"). The MSM is the greater of $100 million , 50% of net premiums written, 15% of the net reserve for losses and loss expenses and 25% of the ECR. The Company's ECR is calculated based on a standard risk-based capital model developed by the Bermuda Monetary Authority ("BMA"). In 2016, the BMA implemented an Economic Balance Sheet ("EBS") framework which was used as the basis to determine the ECR. At December 31, 2018 and 2017 , the required and available statutory capital and surplus were based on this EBS framework. Under the Act, AXIS Specialty Bermuda is restricted as to the payment of dividends for amounts greater than 25% of the prior year’s statutory capital and surplus, whereby an affidavit signed by at least two members of the Board of Directors is required, attesting that any dividend in excess of this amount would not cause the Company to fail to meet its relevant margins. At December 31, 2018 , the maximum dividend AXIS Specialty Bermuda could pay, without a signed affidavit, having met minimum levels of statutory capital and surplus requirements, was approximately $0.9 billion ( 2017 : $0.9 billion ). Ireland Effective January 1, 2016, the Company's Irish subsidiaries, AXIS Specialty Europe SE and AXIS Re SE, are required to maintain the Minimum Capital Requirement ("MCR") subject to a monetary minimum floor, and the Solvency Capital Requirement ("SCR") at all times. The capital requirements are calculated by reference to Solvency II definitions. If an entity falls below the MCR or SCR, the Central Bank of Ireland is authorized to take action to restore the financial position of the Company's Irish subsidiaries. During 2018 and 2017 , the Company's Irish subsidiaries were in compliance with these requirements. The Company's Irish subsidiaries may declare dividends subject to meeting their solvency and capital requirements. The maximum dividend is limited to "excess eligible own funds" which is defined as excess Solvency II capital over the SCR and may also be limited to "profits available for distribution'', which is defined as accumulated realized profits less accumulated realized losses and statutory reserves. At December 31, 2018 , the maximum dividend the Company's Irish subsidiaries could pay, having met their solvency and capital requirements was approximately $37 million ( 2017 : $52 million ). United States The Company's U.S. operations required statutory capital and surplus is determined using the risk-based capital formula ("RBC"), which is the National Association of Insurance Commissioners' (the "Commissioner") method of measuring the minimum capital appropriate for U.S. reporting entities to support its overall business operations in consideration of its size and risk profile. If a company falls below the authorized control level as determined under the RBC, the Commissioner is authorized to take whatever regulatory actions may be considered necessary to protect policyholders and creditors. The maximum dividend that may be paid by the Company's U.S. insurance subsidiaries is restricted by the regulatory requirements of the domiciliary states. Generally, the maximum dividend that may be paid by each of the Company's U.S. insurance subsidiaries is limited to unassigned surplus (statutory equivalent of retained earnings) and may also be limited to statutory net income, net investment income or 10% of total statutory capital and surplus. At December 31, 2018 , the maximum dividend that the Company's U.S. insurance operations could pay without regulatory approval was approximately $130 million ( 2017 : $115 million ). Lloyd's of London The Company operates in the Lloyd’s market through AXIS Corporate Capital UK Limited which is the sole corporate member of Syndicate 1686. Syndicate 1686 was managed by a third party managing agency, Asta Managing Agency Limited until August 2017 when the Company received final authorization from Lloyd's, the Prudential Regulation Authority ("PRA") and the Financial Conduct Authority ("FCA") for its own Lloyd's managing agent, AXIS Managing Agency Ltd. ("AXIS Managing Agency"). Effective August 4, 2017, AXIS Managing Agency assumed management of Syndicate 1686, replacing the Company's third-party managing agency agreement with Asta Managing Agency Limited, which had been in place since 2014. In addition, the Company operates in the Lloyd's market through Novae Corporate Underwriting Limited, the sole corporate member of Syndicate 2007. The Company owned Lloyd’s managing agency, Novae Syndicates Limited ("NSL"), which operated in the Lloyd’s insurance market and managed Syndicate 2007 and SPA 6129, until it was deregistered in 2018. On January 1, 2018, the Company received authorization from Lloyd’s for AXIS Managing Agency to commence management and oversight of Syndicate 2007 and SPA 6129. SPA 6129 commenced trading on January 1, 2016, as a collaboration between Novae and Securis Investment Partners LLP, an insurance linked securities fund manager. For the three months ended December 31, 2017, NSL received a managing agency fee from SPA 6129. For the year ended December 31, 2018, AXIS Managing Agency received a managing agency fee from SPA 6129. The Company ended its collaboration with SPA 6129 in 2018. Corporate members of Lloyd’s and Lloyd’s syndicates are bound by the rules of Lloyd’s, which are prescribed by Bye-laws and Requirements made by the Council of Lloyd’s under powers conferred by the Lloyd’s Act 1982. These rules prescribe members’ membership subscription, the level of their contribution to the Lloyd’s Central Fund and the assets they must deposit with Lloyd’s in support of their underwriting. The Council of Lloyd’s has broad powers to sanction breaches of its rules, including the power to restrict or prohibit a member’s participation on Lloyd’s syndicates. The capital provided to support underwriting, or FAL is not available for distribution for the payment of dividends or for working capital requirements. Corporate members may also be required to maintain funds under the control of Lloyd’s in excess of their capital requirements and such funds also may not be available for distribution for the payment of dividends. Lloyd’s sets the corporate members’ required capital annually through the application of a capital model that is based on regulatory rules pursuant to Solvency II. FAL may be satisfied by cash, certain investments and letters of credit provided by approved banks. At December 31, 2018 , fixed maturities and short term investments with a fair value of $715 million ( 2017 : $557 million ) and cash of $8 million ( 2017 : $12 million ), respectively, were restricted to satisfy AXIS Corporate Capital UK Limited FAL requirements. At December 31, 2018 , fixed maturities and short term investments with a fair value of $528 million ( 2017 : $564 million ), equity securities with a fair value of $40 million ( 2017 : $59 million ), and cash of $16 million ( 2017 : $ nil ) were restricted to satisfy Novae Corporate Underwriting Limited FAL requirements (refer to Note 6 ' Investments '). Each year, corporate members can apply to Lloyd's to release accumulated funds, whether syndicate profits or interest on FAL, which are in excess of the agreed FAL requirements. At December 31, 2018 and 2017 , actual capital and assets exceeded the FAL requirements for Syndicates 1686 and 2007. During 2018 , Syndicate 1686 and 2007 did not apply to release funds for the year ended December 31, 2017 . During 2017 , the release of funds for Syndicate 1686 for the year ended December 31, 2016 was $1.6 million and the release of funds for Syndicate 2007 for the year ended December 31, 2016 was $41 million . Branch Offices The Company's operating subsidiaries in Bermuda and the U.S. maintain branch offices in Singapore and Canada, respectively. The Company's Irish operating subsidiaries maintain branch offices in Switzerland and the U.K. In 2017, the Company ceased operations in Australia. As branch offices are not considered separate entities for regulatory purposes, the required and actual statutory capital and surplus amounts for each jurisdiction in the table above include amounts related to the applicable branch offices. The Company's branch offices in Singapore and Canada are subject to additional minimum capital or asset requirements in their countries of domicile. At December 31, 2018 and 2017 , the actual capital/assets for each of these branches exceeded the relevant local regulatory requirements. Total statutory net income (loss) of the Company's operating subsidiaries was $268 million , $(94) million , $598 million for 2018 , 2017 and 2016 , respectively. The differences between statutory financial statements and statements prepared in accordance with U.S. GAAP vary by jurisdiction, however, the primary differences are that statutory financial statements may not reflect deferred acquisition costs, certain net deferred tax assets, goodwill and intangible assets, unrealized investment gains (losses) on fixed maturities or certain unauthorized reinsurance recoverable balances.

UNAUDITED CONDENSED QUARTERLY F

UNAUDITED CONDENSED QUARTERLY FINANCIAL DATA	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
UNAUDITED CONDENSED QUARTERLY FINANCIAL DATA	An unaudited summary of quarterly financial results is shown in the following table: Quarters ended Mar 31 Jun 30 Sep 30 Dec 31 2018 Net premiums earned $ 1,167,402 $ 1,185,548 $ 1,224,075 $ 1,214,469 Net investment income 100,999 109,960 114,421 113,128 Net investment losses (14,830 ) (45,093 ) (17,628 ) (72,667 ) Underwriting income (loss) 143,737 115,726 59,026 (194,664 ) Net income (loss) available (attributable) to common shareholders 62,546 92,858 43,439 (198,448 ) Earnings (loss) per common share $ 0.75 $ 1.11 $ 0.52 $ (2.37 ) Earnings (loss) per diluted common share $ 0.75 $ 1.11 $ 0.52 $ (2.37 ) 2017 Net premiums earned $ 938,703 $ 981,431 $ 1,017,131 $ 1,211,495 Net investment income 98,664 106,063 95,169 100,908 Net investment gains (losses) (25,050 ) (4,392 ) 14,632 43,038 Underwriting income (loss) 16,385 57,012 (512,853 ) 26,130 Net income (loss) available (attributable) to common shareholders 5,014 85,030 (467,740 ) (38,081 ) Earnings (loss) per common share $ 0.06 $ 1.01 $ (5.61 ) $ (0.46 ) Earnings (loss) per diluted common share $ 0.06 $ 1.01 $ (5.61 ) $ (0.46 ) (1) During the three months ended March 31, June 30, September 30 and December 31, 2018, the Company recognized transaction and reorganization expenses of $13 million , $19 million , $16 million and $19 million , respectively, 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 accident and health business, together with other initiatives designed to increase the Company's efficiency and enhance the Company's profitability while delivering a customer-centric operating model. During the three months ended September 30 and December 31, 2017, the Company recognized transaction and reorganization expenses of $6 million and $21 million , respectively. (2) During the three months ended March 31, June 30, September 30 and December 31, 2018, the Company recognized amortization of VOBA of $57 million , $53 million , $39 million , $23 million , respectively, related to the acquisition of Novae. During the three months ended December 31, 2017, the Company recognized amortization of VOBA of $50 million . Refer to Item 8, Note 3 and Note 5 to the Consolidated Financial Statements ' Business Combinations ' and ' Goodwill and Intangible Assets ' for further details. (3) During the three months ended December 31, 2017, the Company recognized tax expense of $42 million due to the revaluation of net deferred tax asset pursuant to the U.S. Tax Reform. Refer to Item 8, Note 18 to the Consolidated Financial Statements 'Income Taxes' for further details.

SCHEDULE I - SUMMARY OF INVESTM

SCHEDULE I - SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract]
Schedule I	AXIS CAPITAL HOLDINGS LIMITED SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES At December 31, 2018 Amortized cost Fair value Amount shown on the balance sheet (in thousands) Type of investment: Fixed maturities U.S. government and agency $ 1,520,142 $ 1,515,697 $ 1,515,697 Non-U.S. government 507,550 493,016 493,016 Corporate debt 4,990,279 4,876,921 4,876,921 Agency RMBS 1,666,684 1,643,308 1,643,308 CMBS 1,103,507 1,092,530 1,092,530 Non-Agency RMBS 40,732 40,687 40,687 ABS 1,651,350 1,637,603 1,637,603 Municipals 136,068 135,585 135,585 Total fixed maturities $ 11,616,312 11,435,347 11,435,347 Mortgage loans, at amortized cost and fair value 298,650 298,650 Short-term investments, at amortized cost and fair value 144,040 144,040 Equity securities 381,633 381,633 Other investments (1) 445,792 787,787 Equity method investments (2) — 108,103 Total investments $ 12,705,462 $ 13,155,560 (1) Other investments exclude investments where the Company is considered to have the ability to exercise significant influence over the operating and financial policies of the investees. (2) Equity method investments are excluded as the Company has the ability to exercise significant influence over the operating and financial policies of the investees.

SCHEDULE II - CONDENSED FINANCI

SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY	AXIS CAPITAL HOLDINGS LIMITED CONDENSED BALANCE SHEETS – PARENT COMPANY DECEMBER 31, 2018 AND 2017 2018 2017 (in thousands) Assets Investments in subsidiaries $ 5,320,828 $ 5,532,396 Cash and cash equivalents 3,099 10,541 Other assets 9,647 9,480 Total assets $ 5,333,574 $ 5,552,417 Liabilities Intercompany payable $ 247,992 $ 160,950 Dividends payable 51,157 49,907 Other liabilities 4,354 296 Total liabilities 303,503 211,153 Shareholders’ equity Preferred shares 775,000 775,000 Common shares (shares issued 2018: 176,580; 2017: 176,580 2,206 2,206 Additional paid-in capital 2,308,583 2,299,166 Accumulated other comprehensive (income) loss (177,110 ) 92,382 Retained earnings 5,912,812 5,979,666 Treasury shares, at cost (2018: 92,994; 2017: 93,419) (3,791,420 ) (3,807,156 ) Total shareholders’ equity 5,030,071 5,341,264 Total liabilities and shareholders’ equity $ 5,333,574 $ 5,552,417 (1) AXIS Capital has fully and unconditionally guaranteed all obligations of AXIS Specialty Finance LLC, a 100% owned finance subsidiary, related to the issuance of $500 million aggregate principal amount of 5.875% senior unsecured notes. AXIS Capital’s obligations under this guarantee are unsecured senior obligations and rank equally with all other senior obligations of AXIS Capital. (2) AXIS Capital has fully and unconditionally guaranteed all obligations of AXIS Specialty Finance PLC, a 100% owned finance subsidiary, related to the issuance of $250 million aggregate principal amount of 2.65% and $250 million aggregate principal amount of 5.15% senior unsecured notes. AXIS Capital's obligations under this guarantee are unsecured senior obligations and rank equally with all other senior obligations of AXIS Capital. (3) AXIS Capital has fully and unconditionally guaranteed all obligations of AXIS Specialty Finance PLC, a 100% owned finance subsidiary, related to the issuance of $350 million aggregate principal amount of 4.0% senior unsecured notes. AXIS Capital's obligations under this guarantee are unsecured senior obligations and rank equally with all other senior obligations of AXIS Capital. (4) On February 15, 2018, AXIS Capital contributed $105 million to AXIS Specialty Global Holdings to support the capital requirements of its U.S. subsidiaries. SCHEDULE II AXIS CAPITAL HOLDINGS LIMITED CONDENSED STATEMENTS OF OPERATIONS – PARENT COMPANY YEARS ENDED DECEMBER 31, 2018 , 2017 AND 2016 2018 2017 2016 (in thousands) Revenues Net investment income (1) $ 900 $ 2,116 $ 656 Total revenues 900 2,116 656 Expenses General and administrative expenses 29,250 34,933 39,909 Total expenses 29,250 34,933 39,909 Income (loss) before equity in net income (loss) of subsidiaries (28,350 ) (32,817 ) (39,253 ) Equity in net income (loss) of subsidiaries 71,371 (336,152 ) 552,621 Net income (loss) 43,021 (368,969 ) 513,368 Preferred share dividends 42,625 46,810 46,597 Loss on repurchase of preferred shares — — 1,309 Net income (loss) available (attributable) to common shareholders $ 396 $ (415,779 ) $ 465,462 Comprehensive income (loss) $ (158,973 ) $ (154,746 ) $ 579,992 (1) On April 15, 2017 a promissory note of $368 million advanced by AXIS Capital to AXIS Specialty Limited on November 7, 2016, matured. For the year ended December 31, 2017, interest earned at an annual rate of 1.132% and was recorded in net investment income. SCHEDULE II AXIS CAPITAL HOLDINGS LIMITED CONDENSED STATEMENTS OF CASH FLOWS – PARENT COMPANY YEARS ENDED DECEMBER 31, 2018 , 2017 AND 2016 2018 2017 2016 (in thousands) Cash flows from operating activities: Net income (loss) $ 43,021 $ (368,969 ) $ 513,368 Adjustments to reconcile net income (loss) to net cash provided by operating activities: Equity in net income (loss) of subsidiaries (71,371 ) 336,152 (552,621 ) Change in intercompany payable 87,042 94,827 33,286 Dividends received from subsidiaries 200,000 400,000 550,000 Other items (79,927 ) 4,988 17,807 Net cash provided by operating activities 178,765 466,998 561,840 Cash flows from investing activities: Promissory note receivable from subsidiary — — (368,252 ) Capital returned by subsidiary — 368,252 — Net cash provided by (used in) investing activities — 368,252 (368,252 ) Cash flows from financing activities: Net proceeds from issuance of preferred shares — — 531,945 Repurchase of common shares - open market — (261,180 ) (495,426 ) Taxes paid on withholding shares (10,080 ) (24,678 ) (14,329 ) Dividends paid - common shares (133,502 ) (135,032 ) (132,323 ) Repurchase of preferred shares — (351,074 ) (51,769 ) Dividends paid - preferred shares (42,625 ) (52,844 ) (39,909 ) Proceeds from issuance of common shares — — 224 Net cash used in financing activities (186,207 ) (824,808 ) (201,587 ) Increase (decrease) in cash, cash equivalents and restricted cash (7,442 ) 10,442 (7,999 ) Cash, cash equivalents and restricted cash - beginning of year 10,541 99 8,098 Cash, cash equivalents and restricted cash - end of year $ 3,099 $ 10,541 $ 99

SCHEDULE III - SUPPLEMENTARY IN

SCHEDULE III - SUPPLEMENTARY INSURANCE INFORMATION	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
SCHEDULE III - SUPPLEMENTARY INSURANCE INFORMATION	AXIS CAPITAL HOLDINGS LIMITED SUPPLEMENTARY INSURANCE INFORMATION At and year ended December 31, 2018 (in thousands) Deferred acquisition costs Reserve for losses and loss expenses Unearned premiums Net premiums earned Net investment income (1) Net losses and loss expenses Acquisition costs Other operating expenses (2) Net premiums written Insurance $ 209,622 $ 6,426,309 $ 2,061,123 $ 2,362,606 $ — $ 1,494,323 $ 399,193 $ 395,252 $ 2,324,747 Reinsurance 357,000 5,854,460 1,574,635 2,428,889 — 1,695,964 569,642 123,916 2,334,215 Corporate — — — — 438,507 — — 108,221 — Total $ 566,622 $ 12,280,769 $ 3,635,758 $ 4,791,495 $ 438,507 $ 3,190,287 $ 968,835 $ 627,389 $ 4,658,962 At and year ended December 31, 2017 (in thousands) Deferred acquisition costs Reserve for losses and loss expenses Unearned premiums Net premiums earned Net investment income (1) Net losses and loss expenses Acquisition costs Other operating expenses (2) Net premiums written Insurance $ 115,332 $ 7,011,805 $ 2,053,422 $ 1,816,438 $ — $ 1,465,427 $ 270,229 $ 325,368 $ 1,775,825 Reinsurance 358,729 5,985,748 1,587,977 2,332,322 — 1,822,345 553,362 124,115 2,251,318 Corporate — — — — 400,805 — — 129,945 — Total $ 474,061 $ 12,997,553 $ 3,641,399 $ 4,148,760 $ 400,805 $ 3,287,772 $ 823,591 $ 579,428 $ 4,027,143 At and year ended December 31, 2016 (in thousands) Deferred acquisition costs Reserve for losses and loss expenses Unearned premiums Net premiums earned Net investment income (1) Net losses and loss expenses Acquisition costs Other operating expenses (2) Net premiums written Insurance $ 100,149 $ 5,198,070 $ 1,423,891 $ 1,534,282 $ — $ 977,771 $ 206,619 $ 327,351 $ 1,519,559 Reinsurance 338,487 4,499,757 1,545,607 2,171,343 — 1,226,426 540,257 155,350 2,233,415 Corporate — — — — 353,335 — — 120,016 — Total $ 438,636 $ 9,697,827 $ 2,969,498 $ 3,705,625 $ 353,335 $ 2,204,197 $ 746,876 $ 602,717 $ 3,752,974 (1) We evaluate the underwriting results of each of our reportable segments separately from the performance of our investment portfolio therefore, we believe it is appropriate to exclude net investment income from our underwriting profitability measure. (2) Amounts related to our reportable segments reflect underwriting-related general and administrative expenses, which includes those general and administrative expenses that are incremental and/or directly attributable to our individual underwriting operations. Corporate expenses include holding company costs necessary to support our worldwide insurance and reinsurance operations and costs associated with operating as a publicly-traded company. As these costs are not incremental and/or directly attributable to our individual underwriting operations, these expenses are excluded from underwriting-related general and administrative expenses. The reconciliation of underwriting-related general and administrative expenses to general and administrative expenses, the most comparable GAAP measure, is presented in Item 7 ' Management’s Discussion and Analysis of Financial Condition and Results of Operations – Executive Summary – Results of Operations'.

SCHEDULE IV - SUPPLEMENTARY REI

SCHEDULE IV - SUPPLEMENTARY REINSURANCE INFORMATION	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]
SCHEDULE IV - SUPPLEMENTARY REINSURANCE INFORMATION	AXIS CAPITAL HOLDINGS LIMITED SUPPLEMENTARY REINSURANCE INFORMATION YEARS ENDED DECEMBER 31, 2018 , 2017 AND 2016 (in thousands) DIRECT GROSS PREMIUM CEDED TO OTHER COMPANIES ASSUMED FROM OTHER COMPANIES NET AMOUNT PERCENTAGE OF AMOUNT ASSUMED TO NET 2018 Property and Casualty $ 3,258,999 $ 2,163,417 $ 3,074,906 $ 4,170,488 73.7 % Accident and Health 209,041 87,686 367,119 488,474 75.2 % Total $ 3,468,040 $ 2,251,103 $ 3,442,025 $ 4,658,962 73.9 % 2017 Property and Casualty $ 2,228,022 $ 1,523,662 $ 2,814,173 $ 3,518,533 80.0 % Accident and Health 195,104 5,468 318,974 508,610 62.7 % Total $ 2,423,126 $ 1,529,130 $ 3,133,147 $ 4,027,143 77.8 % 2016 Property and Casualty $ 1,975,497 $ 1,215,775 $ 2,564,606 $ 3,324,328 77.1 % Accident and Health 136,681 1,459 293,424 428,646 68.5 % Total $ 2,112,178 $ 1,217,234 $ 2,858,030 $ 3,752,974 76.2 %

SIGNIFICANT ACCOUNTING POLICI_2

SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Basis of presentation	Tabular dollar and share amounts are in thousands, with the exception of per share amounts. All amounts are reported in U.S. dollars. These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") and the rules and regulations of the U.S. Securities and Exchange Commission ("SEC") and include AXIS Capital and its wholly-owned subsidiaries.
Consolidation/VIEs	All inter-company accounts and transactions have been eliminated.
Reclassification	To facilitate comparison of information across periods, certain reclassifications have been made to prior year amounts to conform to the current year's presentation.
Use of estimates	The preparation of these consolidated financial statements requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. While management believes that the amounts included in the consolidated financial statements reflect its best estimates and assumptions, actual results could differ from those estimates. The Company’s principal estimates include: • reserve for losses and loss expenses; • reinsurance recoverable on unpaid losses, including the provision for uncollectible amounts; • gross and net premiums written and net premiums earned; • fair value measurements of financial assets and liabilities; and • other-than-temporary impairments ("OTTI") in the carrying value of available-for-sale securities.
Investments	Fixed Maturities, Available-for-sale, at Fair Value Fixed maturities classified as available-for-sale are reported at fair value (refer to Note 7 ' Fair Value Measurements '). The change in fair values (net unrealized investment gains (losses)) of fixed maturities, net of tax is recognized in accumulated other comprehensive income (loss) ("AOCI") in the consolidated statement of change shareholders’ equity. Net investment income includes interest income and the amortization of market premiums and discounts and is presented net of investment expenses. Investment income is recognized when earned. Purchases and sales of fixed maturities are recorded on a trade-date basis and realized investment gains (losses) on sales of fixed maturities are determined based on the specific identification method. Realized investment gains (losses) on fixed maturities are included in net investments gains (losses) in the consolidated statements of operations. The Company recognizes investment income from fixed maturities based on the constant effective yield method, which includes an adjustment for estimated principal repayments, if applicable. The effective yield used to determine the amortization of fixed maturities subject to prepayment risk (e.g. asset-backed, mortgage-backed and other structured securities) is recalculated and adjusted periodically based upon historical and/or projected future cash flows. Adjustments to the yield for highly-rated prepayable fixed maturities are accounted for using the retrospective method. Adjustments to the yield for other prepayable fixed maturities are accounted for using the prospective method. A fixed maturity is impaired if the fair value of the investment is below amortized cost. On a quarterly basis, the Company assesses whether unrealized investment losses on fixed maturities represent impairments that are other-than-temporary. The Company's impairment review process begins with a quantitative analysis to identify securities to be evaluated for potential OTTI. For identified securities, fundamental analysis is performed that considers the following quantitative and qualitative factors: (i) the duration and the extent of the decline; (ii) the financial condition, near-term and long-term prospects of the issuer of the security; (iii) the reason for the decline (e.g. credit spread widening, credit event, foreign exchange rate movements); (iii) the historical and implied future volatility of the fair value; and (v) the collateral structure and credit support of the security, if applicable. If a fixed maturity is impaired and the Company intends to sell the security or it is more likely than not that the Company will be required to sell the security before its anticipated recovery, the impairment is considered other-than-temporary. In these instances, the full amount of the impairment is charged to net income and is included in net investment gains (losses). In instances where the Company intends to hold the impaired fixed maturity, the Company estimates the anticipated credit loss on the security and recognizes this component of the impairment in net income with a corresponding adjustment to amortized cost (new cost basis) of the security. The new cost basis is adjusted for subsequent increases in fair value where the difference between the new cost basis and the expected cash flows is accreted on a quarterly basis to net investment income over the remaining life of the fixed maturity. The Company recognizes the non-credit component of the impairment (i.e. related to interest rates, market conditions, etc.) in other comprehensive income. Equity Securities, at Fair Value Following the adoption of Accounting Standards Update ("ASU") 2016-01 "Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities , " (refer to ' New Accounting Standards Adopted in 2018' below) Equity securities are reported at fair value (refer to Note 7 ' Fair Value Measurements '). Effective January 1, 2018, following the adoption of ASU 2016-01, the change in the fair values (net unrealized investment gains (losses)) of equity securities, net of tax is recognized in net investments gains (losses) in the consolidated statements of operations. Net investment income includes dividend income and is presented net of investment expenses. Investment income is recognized when earned. Purchases and sales of equity securities are recorded on a trade-date basis and realized investment gains (losses) on sales of equity securities are determined based on the specific identification method. Realized investment gains (losses) on equity securities are included in net investments gains (losses) in the consolidated statements of operations. Prior to the Adoption of ASU 2016-01 Equity securities are reported at fair value. Prior to the adoption of ASU 2016-01, the change in the fair values (net unrealized investment gains (losses)) of equity securities, net of tax was recognized in AOCI in the consolidated statement of changes in shareholders’ equity. An equity security is impaired if the fair value of the investment is below cost. On a quarterly basis, the Company assessed whether unrealized investment losses on equity securities represented impairments that are other-than-temporary and recognized impairments on equity securities in an unrealized loss position when the Company did not have the ability and intent to hold the security for a reasonable period of time to allow for a full recovery. The full amount of the impairment was charged to net income and was included in net realized investment gains (losses) in the consolidated statements of operations. Upon recognition of an other-than-temporary impairment ("OTTI") charge, the new cost basis for the equity security was the cost for an equity security less the OTTI charge recognized in net income. The new cost basis was not adjusted for subsequent increases in fair value. Mortgage Loans Held-for-investment Mortgage loans held-for-investment are reported at amortized cost which is calculated as the unpaid principal balance, adjusted for any unamortized premium or discount, deferred fees or expenses, and is net of valuation allowances. Interest income and prepayment fees are recognized when earned. Interest income is recognized based on an effective yield method which gives effect to the amortization of premiums and accretion of discounts. Other Investments Other investments are recorded at fair value (refer to Note 7 ' Fair Value Measurements '), with both changes in fair value and realized investment gains (losses) reported in net investment income in the consolidated statements of operations. Equity Method Investments Investments in which the Company has significant influence over the operating and financial policies of the investee are classified as equity method investments and are accounted for using the equity method of accounting. In applying the equity method of accounting, investments are initially recorded at cost and are subsequently adjusted based on the Company’s proportionate share of net income or loss of the investee. Adjustments are based on the most recently available financial information from the investee. Changes in the carrying value of these investments are recorded in net income as interest in income (loss) of equity method investments. Short-term Investments Short-term investments primarily comprise highly-liquid debt securities with maturities greater than three months but less than one year from the date of purchase. These investments are carried at amortized cost, which approximates fair value.
Cash and cash equivalents	Cash equivalents include money-market funds, fixed interest deposits and reverse repurchase agreements with a maturity of under 90 days when purchased. Cash and cash equivalents are recorded at amortized cost, which approximates fair value due to the short-term, liquid nature of these securities. Restricted cash primarily relates to funds held in trust to support of obligations in regulatory jurisdictions where the Company operates as a non-admitted carrier and to support the underwriting activities of Syndicate 1686 and Syndicate 2007 at Lloyd's
Premiums (gross premiums written)	Insurance premiums written are recorded in accordance with the terms of the underlying policies. Reinsurance premiums are recorded at the inception of the contract and are estimated based on information received from ceding companies. For multi-year contracts where (re)insurance premiums are payable in annual installments, premiums are recorded at the inception of the contract based on management’s best estimate of total premiums to be received. However, premiums are normally recognized on an annual basis for multi-year contracts where the cedant has the ability to unilaterally commute or cancel coverage within the term of the policy. The remaining annual premiums are included as written at each successive anniversary date within the multi-year term. Any adjustments to insurance and reinsurance premium estimates are recognized in the period in which they are determined.
Premiums (net premiums earned)	(Re)insurance premiums are earned evenly over the period during which the Company is exposed to the underlying risk, which is generally one to two years with the exception of multi-year contracts. Unearned premiums represent the portion of premiums written which relates to the unexpired risks under contracts in force. Reinstatement premiums are recognized and earned at the time a loss event occurs, where the coverage limits for the remaining life of the contract are reinstated under pre-defined contract terms. The accrual of reinstatement premiums is based on estimates of losses and loss adjustment expenses, which reflects management’s judgment, as described in Note 2(d) ' Losses and Loss Expenses ' below.
Premiums (receivables)	Premiums receivable balances are reviewed for impairment at least quarterly and an allowance is established for amounts considered uncollectible.
Acquisition costs	Acquisition costs vary with and are directly related to the successful acquisition efforts of acquiring new or renewing existing (re)insurance contracts and consist primarily of fees and commissions paid to brokers and premium taxes. Acquisition costs are shown net of commissions earned on ceded reinsurance. Net acquisition costs are deferred and charged to expense as the related premium is earned. Insurance and reinsurance premiums balance receivable is presented net of acquisition costs when contract terms provide for the right of offset. Anticipated losses and loss expenses, other costs and investment income related to these premiums are considered in assessing the recoverability of deferred acquisition costs. If deferred amounts are estimated to be unrecoverable, they are expensed. Compensation expenses for personnel involved in contract acquisition, as well as advertising costs, are expensed as incurred.
Losses and loss expenses	Reserve for losses and loss expenses represents an estimate of the unpaid portion of the ultimate liability for losses and loss expenses for (re)insured events that have occurred at or before the balance sheet date. These amounts reflect both claims that have been reported ("case reserves") and claims that have been incurred but not yet reported ("IBNR") and are reduced for estimated amounts of salvage and subrogation recoveries. The Company reviews its reserve for losses and loss expenses on a quarterly basis. Case reserves are primarily established based on amounts reported from insureds and/or their brokers. Management estimates IBNR after reviewing detailed actuarial analyses and applying informed judgment regarding qualitative factors that may not be fully captured in the actuarial estimates. A variety of actuarial methods are utilized in this process, including the Expected Loss Ratio, Chain Ladder and Bornhuetter Ferguson methods. The estimate is highly dependent on management’s judgment as to which method(s) are most appropriate for a particular accident year and line of business. Historical claims data is often supplemented with industry benchmarks when applying these methodologies. Any adjustments to reserve for losses and loss expenses estimates are recognized in the period in which they are determined. While the Company believes that its reserves for losses and loss expenses are adequate, this estimate requires significant judgment and new information, events or circumstances may result in ultimate losses that are materially greater or less than provided for in the consolidated balance sheets.
Reinsurance	In the normal course of business, the Company purchases reinsurance protection to limit its ultimate losses from catastrophic events and to reduce its loss aggregation risk. The premiums paid to reinsurers (i.e. ceded premiums written) are expensed over the coverage period. Prepaid reinsurance premiums represent the portion of premiums ceded which relate to the unexpired term of the contracts in force. Reinstatement premiums ceded are recognized and earned at the time a loss event occurs, where the coverage limits for the remaining life of the contract are reinstated under pre-defined contract terms. Reinsurance recoverable related to case reserves is estimated on a case-by-case basis by applying the terms of any applicable reinsurance cover to individual case reserve estimates. Reinsurance recoverable related to IBNR is generally developed as part of our loss reserving process, therefore, its estimation is subject to similar risks and uncertainties as the estimation of IBNR. Reinsurance recoverable is presented net of a provision for uncollectible amounts, reflecting the amount the Company believes ultimately will not be recovered due to reinsurer insolvency, contractual disputes and/or some other reason. The Company applies case-specific provisions against reinsurance recoverable on unpaid and paid losses that it deems unlikely to be collected in full. In addition, the Company uses a default analysis to estimate the provision for uncollectible amounts on the remainder of the reinsurance recoverable balance. The estimates of reinsurance recoverable and the associated provision for uncollectible amounts require management’s judgment and are reviewed in detail on a quarterly basis. Any adjustments to the provision for uncollectible amounts are recognized in the period in which they are determined. Retroactive Reinsurance Retroactive reinsurance reimburses a ceding company for liabilities incurred as a result of past insurable events covered under contracts subject to the reinsurance. In certain instances, reinsurance contracts cover losses both on a prospective basis and on a retroactive basis and where practical the Company bifurcates the prospective and retrospective elements of these reinsurance contracts and accounts for each element separately. Initial gains in connection with retroactive reinsurance contracts are deferred and amortized into income over the settlement period while losses are recognized immediately. When changes in the estimated amount recoverable from the reinsurer or in the timing of receipts related to that amount occur, a cumulative amortization adjustment is recognized in net income in the period of the change so that the deferred gain reflects the balance that would have existed had the revised estimate been available at the inception of the reinsurance transaction.
Foreign exchange	The functional currency of the Company and the majority of its subsidiaries is the U.S. dollar. All foreign currency transactions are initially measured and recorded in the Company’s functional currency using the rates of exchange prevailing at the transaction date. Monetary assets and liabilities denominated in foreign currency are remeasured to functional currency at the rates of exchange in effect at the balance sheet date with the resulting foreign currency gains (losses) generally being recognized in the consolidated statements of operations. Foreign currency gains (losses) related to available-for-sale investments denominated in foreign currency represent an unrealized appreciation (depreciation) in the market value of the securities and are included in the relevant component of AOCI. Non-monetary assets and liabilities denominated in foreign currency are not subsequently remeasured. The Company’s reporting currency is the U.S. dollar. Assets and liabilities of the Company's subsidiaries and branches where the functional currency is not the U.S. dollar, are translated into U.S. dollars using the rates of exchange in effect at the balance sheet date, and revenue and expenses are translated using the weighted average foreign exchange rates for the period. The effect of translation adjustments is reported as a separate component of AOCI in the consolidated statement of change shareholders’ equity.
Share-based compensation	The Company is authorized to issue restricted shares, restricted stock units, performance units, stock options, stock appreciation rights and other equity-based awards to its employees and directors. The Company's plan includes both share-settled and cash-settled service and performance based awards. The fair value of share-settled service and performance based awards is based on the market value of the Company's common share measured at the grant date and is expensed over the requisite service period. The fair value cash-settled service and performance based awards is also based on the fair market value of Company's common shares at the grant date and is expensed over the requisite service period. In addition, the fair value of the cash-settled service and performance based awards is recognized as a liability in the consolidated balance sheet and is remeasured at the end of each reporting period. Effective, January 1, 2017, the Company made an accounting policy election to account for forfeitures when they occur.
Derivatives instruments	The Company may enter into derivative instruments such as futures, options, interest rate swaps and foreign currency forward contracts as part of its overall foreign currency risk management strategy, to obtain exposure to a particular financial market or for yield enhancement. During 2013, the Company began to write derivative based risk management products designed to address weather and commodity price risks, with the objective of generating profits on a portfolio basis. Effective July 1, 2017, the Company no longer writes derivative-based risk management products which address weather risks. From time to time the Company may also enter into (re)insurance contracts that meet the Financial Accounting Standards Board's ("FASB") definition of a derivative contract. The Company measures all derivative instruments at fair value (refer to Note 7 ' Fair Value Measurements ') and recognizes them as either assets or liabilities in the consolidated balance sheets. Subsequent changes in fair value and any realized gains or losses are recognized in the consolidated statements of operations.
Goodwill and intangible assets	The Company recognizes goodwill and other intangible assets in connection with certain acquisitions. Goodwill represents the excess of the purchase price paid over the fair value of the net assets acquired in these acquisition and is not amortized. Other intangible assets with a finite life are amortized over the estimated useful live of the intangible asset. Other intangible assets with an indefinite life are not amortized. The Company tests goodwill and indefinite intangible assets for potential impairment during the fourth quarter each year and between annual tests if an event occurs or changes in circumstances indicate that the asset is impaired. Such events or circumstances may include an economic downturn in a geographic market or a change in the assessment of future operations. For the purposes of evaluating goodwill for impairment, the Company may first perform a qualitative assessment to determine whether it is necessary to perform a quantitative goodwill impairment test. If determined to be necessary, the quantitative test compares the fair value of a reporting unit with its carrying amount, including goodwill. Subsequent to the adoption of ASU 2017-04, "Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment " (refer to ' New Accounting Standards Adopted in 2018' below) if the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is considered not impaired. If the carrying amount of the reporting unit exceeds the fair value, an impairment loss is recognized in an amount equal to that excess, limited to the total amount of goodwill allocated to that reporting unit. For the purposes of evaluating indefinite lived intangibles for impairment, the Company may first perform a qualitative assessment to determine whether it is necessary to perform the quantitative impairment test. If the Company elects to perform a qualitative assessment, it first assesses qualitative factors to determine whether it is more likely than not that an indefinite lived intangible asset is impaired. If the Company determines that it is not more likely than not that the indefinite lived intangible asset is impaired, the Company does not calculate the fair value of the intangible asset and perform the quantitative impairment test. For the purposes of evaluating goodwill and indefinite lived intangible assets for impairment, the Company has an unconditional option to bypass the qualitative assessment in any period and proceed directly to performing the quantitative impairment test. The Company may resume performing the qualitative assessment in any subsequent period. For other definite lived intangible asset the Company tests for recoverability whenever events or changes in circumstances indicate its carrying amount may not be recoverable. The Company recognizes an impairment loss if the carrying amount of the asset is not recoverable and exceeds its fair value. The carrying amount of a definite lived intangible asset is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. If goodwill or an intangible asset is impaired, the carrying value of the asset is reduced to fair value and a corresponding expense is recorded in the consolidated statements of operations.
Income taxes	Certain subsidiaries and branches of the Company operate in jurisdictions where they are subject to taxation. Current and deferred income taxes are charged or credited to net income, or in certain cases to AOCI, based upon enacted tax laws and rates applicable in the relevant jurisdiction in the period in which the tax becomes accruable or realizable. Deferred income taxes are provided for all temporary differences between the bases of assets and liabilities used in the consolidated balance sheets and those used in the various jurisdictional tax returns. When the assessment indicates that it is more likely than not that a portion of a deferred tax asset will not be realized in the foreseeable future, a valuation allowance against deferred tax assets is recorded. The Company recognizes the tax benefits of uncertain tax positions only when the position is more-likely-than-not to be sustained upon audit by the relevant taxing authorities.
Treasury shares	Common shares repurchased by the Company and not subsequently canceled are classified as treasury shares and are recorded at cost. This results in a reduction of shareholders’ equity in the consolidated balance sheets. When shares are reissued from treasury, the Company uses the average cost method to determine the cost of the reissued shares.
New Accounting Standards Adopted, Recently Issued Accounting Standards Not Yet Adopted	New Accounting Standards Adopted in 2018 Recognition and Measurement of Financial Assets and Financial Liabilities Fixed maturities and equity securities are reported at fair value at the balance sheet date (refer to Note 7 ' Fair Value Measurements '). Effective January 1, 2018, the Company adopted ASU 2016-01 "Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities, " which: • requires equity investments (except those accounted for under the equity method of accounting, investments that are consolidated or those that meet a practicability exception) to be measured at fair value with changes in fair value recognized in net income; • simplifies the impairment assessment of equity investments without readily determinable values by requiring a qualitative assessment to identify impairment, eliminates the requirement to disclose the methods and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost, • requires the use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes; • requires separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the organization has elected to measure the liabilities in accordance with the fair value option; • requires the separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements; and • clarifies that the reporting organization should evaluate the need for a valuation allowance on a deferred tax asset related to available for sale securities in combination with the organization’s other deferred tax assets. Upon adoption of this guidance, net unrealized investment gains on equity securities of $70 million , net of deferred income taxes of $13 million , were reclassified from accumulated other comprehensive income to retained earnings. Revenue from Contracts with Customers Effective January 1, 2018, the Company adopted Accounting Standards Update ("ASU") 2014-09 "Revenue from Contracts with Customers (Topic 606)," using the modified retrospective transition approach. This guidance affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards, such as accounting for insurance contracts. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The Company generated fee income of $32 million for the year ended December 31, 2018 which is within the scope of this ASU. These fees represent service fees earned by the Company's reinsurance segment related to services provided to strategic capital partners and are recognized when the related services have been performed. Given that the timing and measurement of revenue associated with impacted contracts did not change, the adoption of this guidance did not have a material impact on the Company's results of operations, financial condition and liquidity. Classification of Certain Cash Receipts and Cash Payments Effective January 1, 2018, the Company adopted ASU 2016-15, "Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments, " which addresses diversity in practice in how eight specific cash receipts and cash payments should be presented and classified on the statement of cash flows. The adoption of this guidance did not impact the Company's results of operations, financial condition and liquidity. Restricted Cash Effective January 1, 2018, the Company adopted ASU 2016-18, "Statement of Cash Flows (Topic 230) - Restricted Cash, " which addresses diversity in practice in the classification and presentation of changes in restricted cash on the statement of cash flows. This guidance requires a statement of cash flows to explain the change during the period in the total of cash, cash equivalents, restricted cash and restricted cash equivalents. Transfers between cash and cash equivalents and restricted cash and restricted cash equivalents will no longer be presented on the statement of cash flows. To facilitate comparison of the Company's consolidated statements of cash flows, the Company adopted this guidance utilizing the full retrospective approach for all periods presented in the Company's consolidated financial statements. As a result, the Company's consolidated statements of cash flows now explains the change during the period in the total of cash, cash equivalents, and restricted cash. Therefore, restricted cash is now included with cash and cash equivalents in the reconciliation of the beginning of period and end of period total amounts shown on the statement of cash flows. The adoption of this guidance did not impact the Company's results of operations, financial condition and liquidity. Stock Compensation - Scope of Modification Accounting Effective January 1, 2018, the Company adopted ASU 2017-09 "Compensation - Stock Compensation (Topic 718) - Scope of Modification Accounting, " which provides clarity and reduces diversity in practice of applying the guidance in Topic 718 to a change to the terms or conditions of a share-based payment award. This ASU provides guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. The guidance states that an entity should account for the effects of a modification unless all the following are met: 1. the fair value of the modified award is the same as the fair value of the original award immediately before the original award is modified; 2. the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified; and the classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the original award is modified. The current disclosure requirements in Topic 718 apply regardless of whether an entity is required to apply modification accounting under the amendments in this Update. The adoption of this guidance did not impact the Company's results of operations, financial condition and liquidity. Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income Effective January 1, 2018, the Company adopted ASU 2018-02 "Income Statement - Reporting Comprehensive Income (Topic 220) - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income " which was a response to a financial reporting issue that arose as a consequence of the U.S. federal government tax bill, H.R.1, An Act to Provide for Reconciliation Pursuant to Titles II and V of the Concurrent Resolution on the Budget for Fiscal Year 2018 ("U.S. Tax Reform"), which was enacted on December 22, 2017. U.S. GAAP currently requires deferred tax liabilities and assets to be adjusted for the effect of a change in tax laws or rates with the effect included in income from continuing operations in the reporting period that includes the enactment date. This guidance is applicable even in situations in which the related income tax effects of items in accumulated other comprehensive income were originally recognized in other comprehensive income rather than in income from continuing operations. As the adjustment of deferred taxes due to the reduction of the historical corporate income tax rate to the newly enacted corporate income tax rate is required to be included in income from continuing operations, the tax effects of items within accumulated other comprehensive income (referred to as stranded tax effects for purposes of this Update) do not reflect the appropriate tax rate. The amendments in this Update allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from U.S. Tax Reform. Consequently, the amendments eliminate the stranded tax effects resulting from U.S. Tax Reform and will improve the usefulness of information reported to financial statement users. However, because the amendments only relate to the reclassification of the income tax effects of U.S. Tax Reform, the underlying guidance that requires that the effect of a change in tax laws or rates be included in income from continuing operations is not affected. As a consequence of U.S. Tax Reform, the Company recognized a tax benefit of $2 million related to the revaluation of net deferred tax liabilities associated with the reduction in the U.S. corporate income tax rate from 35% to 21%, attributable to net unrealized investment gains associated with investments held by the Company's U.S. domiciled entities. Upon adoption of this guidance, the tax benefit of $2 million was reclassified from accumulated other comprehensive income into retained earnings. Simplifying the Test for Goodwill Impairment Effective October 1, 2018, the Company adopted ASU 2017-04, "Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment " that eliminates the requirement to calculate the implied fair value of goodwill (i.e., Step 2 of the current goodwill impairment test) to measure a goodwill impairment charge. Instead, an impairment charge will be based on the excess of a reporting unit's carrying amount over its fair value (i.e., measure the charge based on Step 1 of the current goodwill impairment test). The adoption of this guidance did not impact the Company's results of operations, financial condition and liquidity. m) Recently Issued Accounting Standards Not Yet Adopted Leases In February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)" which provided a new comprehensive model for lease accounting. Topic 842 will require 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. In July 2018, the FASB issued ASU 2018-11, "Leases (Topic 842) - Targeted Improvements " which provides an additional (and optional) transition method to adopt the new lease guidance. A company electing this additional (and optional) transition method must provide the required Topic 840 disclosures for all periods that continue to be in accordance with Topic 840. However, these amendments do not change the existing disclosure requirements in Topic 840, in particular these amendments do not create interim disclosure requirements. This guidance is effective for interim and annual reporting periods beginning after December 15, 2018, with early adoption permitted. The Company will adopt Topic 842 effective January 1, 2019, by electing the additional transition method provided in ASU 2018-11. The Company will also elect the package of practical expedients permitted under the transition guidance of Topic 842, which must be elected as a package and applied consistently to all leases. The package of practical expedients permits 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 will make an accounting policy election not to record leases with an initial term of 12 months or less (short-term) in the Company's consolidated balance sheets. The Company will recognize expense for short-term lease payments on a straight-line basis over the lease term in the Company's consolidated statements of operations. At December 31, 2018, the Company expects the adoption of this guidance will result in the recognition of lease assets and lease liabilities of approximately $149 million in the Company's consolidated balance sheets at January 1, 2019, related to existing office property and equipment leases. The adoption of this guidance will not impact the Company's results of operations and liquidity. 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 measured at amortized cost 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 amortized 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. Premium Amortization on Purchased Callable Debt Securities In March 2017, the FASB issued 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 Company plans to adopt this guidance effective January 1, 2019. The adoption of this guidance will not impact the Company's results of operations, financial condition and liquidity. Changes to Disclosures on Fair Value Measurement In August 2018, the FASB issued ASU 2018-13 "Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement " to improve the effectiveness of fair value measurement disclosures. This guidance is effective for interim and annual reporting periods, beginning after December 15, 2019, with early adoption permitted. The Company plans to adopt this guidance effective January 1, 2019. As this guidance relates solely to financial statement disclosures, the adoption of ASU 2016-18, will not impact the Company's results of operations, financial condition and liquidity.

BUSINESS COMBINATIONS (Tables)

BUSINESS COMBINATIONS (Tables)	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Schedule of recognized identified assets acquired and liabilities assumed	The fair value of the assets acquired and liabilities assumed and the allocation of the purchase price on the acquisition date are summarized in the following table: Total purchase price paid $ 616,926 Assets Investments 1,733,611 Cash and cash equivalents 191,337 Insurance and reinsurance premium balances receivable 472,180 Reinsurance recoverable on unpaid and paid losses 787,907 Prepaid reinsurance premiums 197,907 Other assets 42,696 Total assets acquired $ 3,425,638 Liabilities Reserve for losses and loss expenses 2,125,634 Unearned premiums 717,442 Insurance and reinsurance balances payable 273,405 Notes payable 101,846 Other liabilities 124,585 Total liabilities assumed $ 3,342,912 Fair value of identifiable intangible assets: Value of business acquired - definite lived intangible asset 256,942 Identifiable definite lived intangible assets 128,463 Identifiable indefinite lived intangible assets 94,748 Excess purchase price over fair value of net assets acquired assigned to goodwill $ 54,047
Intangible assets acquired as part of business combination	Identifiable intangible assets at the acquisition date are included in intangible assets in the consolidated balance sheets and are shown in the following table: Economic useful life Indefinite lived intangible assets Lloyd's syndicate capacity $ 94,748 Indefinite Finite lived other intangible assets Distribution networks: Coverholders 63,565 12 years Large brokers 46,641 15 years Small & Mid-sized Enterprise ("SME") brokers 14,126 12 years Managing General Agent ("MGA") Contract 4,131 7 years Total 128,463 Identifiable intangible assets at October 2, 2017 $ 223,211
Business acquisition, pro forma information	The following selected audited information is a summary of the results of Novae that has been included in the consolidated financial statements for the year ended December 31, 2017. From acquisition date to (in thousands) December 31, 2017 Net premiums written $ 140,635 Total revenue 191,929 Total expenses (197,895 ) Net income $ (5,966 ) Years ended December 31, 2017 2016 (in thousands) (unaudited) (unaudited) Net premiums earned $ 4,728,700 $ 4,560,800 Net income $ (468,400 ) $ 532,500

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2018
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 amounts of allocated goodwill and intangible assets: At and year ended December 31, 2018 Insurance Reinsurance Total Gross premiums written $ 3,797,592 $ 3,112,473 $ 6,910,065 Net premiums written 2,324,747 2,334,215 4,658,962 Net premiums earned 2,362,606 2,428,889 4,791,495 Other insurance related income 3,460 7,162 10,622 Net losses and loss expenses (1,494,323 ) (1,695,964 ) (3,190,287 ) Acquisition costs (399,193 ) (569,642 ) (968,835 ) General and administrative expenses (395,252 ) (123,916 ) (519,168 ) Underwriting income $ 77,298 $ 46,529 123,827 Corporate expenses (108,221 ) Net investment income 438,507 Net investment losses (150,218 ) Foreign exchange gains 29,165 Interest expense and financing costs (67,432 ) Transaction and reorganization expenses (66,940 ) Amortization of value of business acquired (172,332 ) Amortization of intangible assets (13,814 ) Income before income taxes and interest in income (loss) of equity method investments $ 12,542 Net loss and loss expense ratio 63.2 % 69.8 % 66.6 % Acquisition cost ratio 16.9 % 23.5 % 20.2 % General and administrative expense ratio 16.8 % 5.1 % 13.1 % Combined ratio 96.9 % 98.4 % 99.9 % Total intangible assets $ 379,285 $ — $ 379,285 At and year ended December 31, 2017 Insurance Reinsurance Total Gross premiums written $ 2,814,918 $ 2,741,355 $ 5,556,273 Net premiums written 1,775,825 2,251,318 4,027,143 Net premiums earned 1,816,438 2,332,322 4,148,760 Other insurance related income (loss) 2,944 (4,184 ) (1,240 ) Net losses and loss expenses (1,465,427 ) (1,822,345 ) (3,287,772 ) Acquisition costs (270,229 ) (553,362 ) (823,591 ) General and administrative expenses (325,368 ) (124,115 ) (449,483 ) Underwriting loss $ (241,642 ) $ (171,684 ) (413,326 ) Corporate expenses (129,945 ) Net investment income 400,805 Net investment gains 28,226 Foreign exchange losses (134,737 ) Interest expense and financing costs (54,811 ) Bargain purchase gain 15,044 Transaction and reorganization expenses (26,718 ) Amortization of value of business acquired (50,104 ) Amortization of intangible assets (2,543 ) Loss before income taxes and interest in income (loss) of equity method investments $ (368,109 ) Net loss and loss expense ratio 80.7 % 78.1 % 79.2 % Acquisition cost ratio 14.9 % 23.7 % 19.9 % General and administrative expense ratio 17.9 % 5.3 % 14.0 % Combined ratio 113.5 % 107.1 % 113.1 % Total intangible assets $ 566,828 $ — $ 566,828 At and year ended December 31, 2016 Insurance Reinsurance Total Gross premiums written $ 2,432,475 $ 2,537,733 $ 4,970,208 Net premiums written 1,519,559 2,233,415 3,752,974 Net premiums earned 1,534,282 2,171,343 3,705,625 Other insurance related income 89 7,133 7,222 Net losses and loss expenses (977,771 ) (1,226,426 ) (2,204,197 ) Acquisition costs (206,619 ) (540,257 ) (746,876 ) General and administrative expenses (327,351 ) (155,350 ) (482,701 ) Underwriting income $ 22,630 $ 256,443 279,073 Corporate expenses (120,016 ) Net investment income 353,335 Net investment losses (60,525 ) Foreign exchange gains 121,295 Interest expense and financing costs (51,360 ) Income before income taxes and interest in income (loss) of equity method investments $ 521,802 Net loss and loss expense ratio 63.7 % 56.5 % 59.5 % Acquisition cost ratio 13.5 % 24.9 % 20.2 % General and administrative expense ratio 21.3 % 7.1 % 16.2 % Combined ratio 98.5 % 88.5 % 95.9 % Total intangible assets $ 85,049 $ — $ 85,049
GROSS PREMIUMS WRITTEN BY GEOGRAPHICAL LOCATION OF SUBSIDIARIES	The following table presents gross premiums written by the geographical location of the Company's subsidiaries: Year ended December 31, 2018 2017 2016 Bermuda $ 606,452 $ 529,425 $ 465,980 Ireland 1,805,882 1,569,956 1,650,229 U.S. 2,811,537 2,814,933 2,562,789 Lloyd's of London 1,686,194 641,959 291,210 Total gross premium written $ 6,910,065 $ 5,556,273 $ 4,970,208
NET PREMIUMS EARNED BY SEGMENT AND LINE OF BUSINESS	The following table presents net premiums earned by segment and line of business: Year ended December 31, 2018 2017 2016 Insurance Property $ 796,945 $ 543,342 $ 426,918 Marine 300,944 181,533 150,046 Terrorism 49,150 36,084 33,279 Aviation 74,203 75,107 44,980 Credit and political risk 102,825 56,432 57,964 Professional lines 570,241 519,759 510,806 Liability 229,373 188,770 169,182 Accident and health 207,777 199,121 141,107 Discontinued lines - Novae 31,148 16,290 — Total Insurance 2,362,606 1,816,438 1,534,282 Reinsurance Catastrophe 250,016 209,470 199,825 Property 317,038 304,376 272,403 Professional lines 220,687 226,622 289,868 Credit and surety 250,276 244,186 252,210 Motor 438,693 371,501 318,863 Liability 363,292 351,940 332,479 Agriculture 176,435 195,391 142,501 Engineering 67,932 66,291 62,833 Marine and other 35,570 64,449 57,322 Accident and health 299,813 289,925 243,039 Discontinued lines - Novae 9,137 8,171 — Total Reinsurance 2,428,889 2,332,322 2,171,343 Total $ 4,791,495 $ 4,148,760 $ 3,705,625

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
SCHEDULE OF GOODWILL AND INTANGIBLE ASSETS	The table below provides details of goodwill and intangible assets related to the Company's insurance segment: Goodwill Intangible assets with an indefinite life Intangible assets with a finite life Total Balance at December 31, 2016 Gross amount $ 42,237 $ 26,036 $ 23,030 $ 91,303 Accumulated amortization n/a n/a (9,356 ) (9,356 ) Accumulated translation adjustment 4,911 — — 4,911 47,148 26,036 13,674 86,858 Amortization n/a n/a (1,809 ) (1,809 ) Balance at December 31, 2017 Gross amount (1) 42,237 26,036 23,030 91,303 Accumulated amortization (1) n/a n/a (11,165 ) (11,165 ) Accumulated translation adjustment 4,911 — — 4,911 47,148 26,036 11,865 85,049 Acquired during the year 54,855 94,748 387,545 537,148 Amortization n/a n/a (55,369 ) (55,369 ) Balance at December 31, 2018 Gross amount $ 97,092 $ 120,784 $ 410,575 $ 628,451 Accumulated amortization n/a n/a (66,534 ) (66,534 ) Accumulated translation adjustment 4,911 — — 4,911 102,003 120,784 344,041 566,828 Amortization n/a n/a (184,043 ) (184,043 ) Impairment charge — — (3,500 ) (3,500 ) $ 102,003 $ 120,784 $ 156,498 $ 379,285 n/a – not applicable
SCHEDULE OF FINITE-LIVED INTANGIBLE ASSETS	The tables below provide details of the gross amount and accumulated amortization by category of VOBA and intangible assets: VOBA and intangible assets Balance At December 31, 2018 Gross amount Accumulated amortization and impairment Total U.S. state licenses $ 26,036 n/a $ 26,036 Customer lists, trademark and non-compete - Media Pro 9,700 (9,598 ) 102 Customer relationships and customers lists - Ternian 13,330 (4,999 ) 8,331 VOBA - Aviabel 2,140 (2,140 ) — VOBA - Novae 256,942 (221,228 ) 35,714 Syndicate capacity 94,748 n/a 94,748 Coverholders 63,565 (6,622 ) 56,943 Large brokers 46,641 (3,888 ) 42,753 SME brokers 14,126 (1,471 ) 12,655 MGA contract (1) 4,131 (4,131 ) — $ 531,359 $ (254,077 ) $ 277,282 (1) During the year ended December 31, 2018, an impairment charge of $3,500 was recognized related to the termination of the MGA contract intangible asset identified in connection with the acquisition of Novae. VOBA and Intangible assets Balance At December 31, 2017 Gross amount Accumulated amortization Total U.S. state licenses $ 26,036 n/a $ 26,036 Customer lists, trademark and non-compete - Media Pro 9,700 (9,244 ) 456 Customer relationships and customers lists - Ternian 13,330 (3,666 ) 9,664 VOBA - Aviabel 2,140 (977 ) 1,163 VOBA - Novae 256,942 (50,104 ) 206,838 Syndicate capacity 94,748 n/a 94,748 Coverholders 63,565 (1,324 ) 62,241 Large brokers 46,641 (777 ) 45,864 SME brokers 14,126 (294 ) 13,832 MGA contract 4,131 (148 ) 3,983 $ 531,359 $ (66,534 ) $ 464,825
SCHEDULE OF INDEFINITE-LIVED INTANGIBLE ASSETS	The tables below provide details of the gross amount and accumulated amortization by category of VOBA and intangible assets: VOBA and intangible assets Balance At December 31, 2018 Gross amount Accumulated amortization and impairment Total U.S. state licenses $ 26,036 n/a $ 26,036 Customer lists, trademark and non-compete - Media Pro 9,700 (9,598 ) 102 Customer relationships and customers lists - Ternian 13,330 (4,999 ) 8,331 VOBA - Aviabel 2,140 (2,140 ) — VOBA - Novae 256,942 (221,228 ) 35,714 Syndicate capacity 94,748 n/a 94,748 Coverholders 63,565 (6,622 ) 56,943 Large brokers 46,641 (3,888 ) 42,753 SME brokers 14,126 (1,471 ) 12,655 MGA contract (1) 4,131 (4,131 ) — $ 531,359 $ (254,077 ) $ 277,282 (1) During the year ended December 31, 2018, an impairment charge of $3,500 was recognized related to the termination of the MGA contract intangible asset identified in connection with the acquisition of Novae. VOBA and Intangible assets Balance At December 31, 2017 Gross amount Accumulated amortization Total U.S. state licenses $ 26,036 n/a $ 26,036 Customer lists, trademark and non-compete - Media Pro 9,700 (9,244 ) 456 Customer relationships and customers lists - Ternian 13,330 (3,666 ) 9,664 VOBA - Aviabel 2,140 (977 ) 1,163 VOBA - Novae 256,942 (50,104 ) 206,838 Syndicate capacity 94,748 n/a 94,748 Coverholders 63,565 (1,324 ) 62,241 Large brokers 46,641 (777 ) 45,864 SME brokers 14,126 (294 ) 13,832 MGA contract 4,131 (148 ) 3,983 $ 531,359 $ (66,534 ) $ 464,825
FUTURE AMORTIZATION EXPENSE	The table below provides details of estimated amortization expense of VOBA and intangible assets with a finite life: VOBA Intangible assets Total 2019 26,722 11,017 37,739 2020 5,139 10,916 16,055 2021 3,853 10,916 14,769 2022 — 10,916 10,916 2023 — 10,916 10,916 2024 and thereafter — 66,103 66,103 Total remaining amortization expense 35,714 120,784 156,498 Indefinite lived intangible assets — 120,784 120,784 Total intangible assets $ 35,714 $ 241,568 $ 277,282

INVESTMENTS (Tables)

INVESTMENTS (Tables)	12 Months Ended
	Dec. 31, 2018
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 Gross Gross Fair Non-credit (5) 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 ) At December 31, 2017 Fixed maturities U.S. government and agency $ 1,727,643 $ 1,735 $ (16,909 ) $ 1,712,469 $ — Non-U.S. government 798,582 17,240 (9,523 ) 806,299 — Corporate debt 5,265,795 61,922 (29,851 ) 5,297,866 — Agency RMBS (1) 2,414,720 8,132 (27,700 ) 2,395,152 — CMBS (2) 776,715 4,138 (3,125 ) 777,728 — Non-Agency RMBS 45,713 1,917 (799 ) 46,831 (853 ) ABS (3) 1,432,884 5,391 (1,994 ) 1,436,281 — Municipals (4) 149,167 1,185 (972 ) 149,380 — Total fixed maturities $ 12,611,219 $ 101,660 $ (90,873 ) $ 12,622,006 $ (853 ) (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 Gross Fair 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 At December 31, 2017 Equity securities Common stocks $ 22,836 $ 3,412 $ (590 ) $ 25,658 Exchange-traded funds 356,252 71,675 (294 ) 427,633 Bond mutual funds 173,779 9,440 (999 ) 182,220 Total equity securities $ 552,867 $ 84,527 $ (1,883 ) $ 635,511
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 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 % At December 31, 2017 Maturity Due in one year or less $ 486,659 $ 484,663 3.8 % Due after one year through five years 4,906,207 4,912,189 38.9 % Due after five years through ten years 2,338,964 2,350,433 18.6 % Due after ten years 209,357 218,729 1.7 % 7,941,187 7,966,014 63.0 % Agency RMBS 2,414,720 2,395,152 19.0 % CMBS 776,715 777,728 6.2 % Non-Agency RMBS 45,713 46,831 0.4 % ABS 1,432,884 1,436,281 11.4 % Total $ 12,611,219 $ 12,622,006 100.0 %
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 December 31, 2018 (1) 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 ) At December 31, 2017 Fixed maturities U.S. government and agency $ 194,916 $ (5,963 ) $ 1,389,792 $ (10,946 ) $ 1,584,708 $ (16,909 ) Non-U.S. government 62,878 (6,806 ) 204,110 (2,717 ) 266,988 (9,523 ) Corporate debt 407,300 (11,800 ) 2,041,845 (18,051 ) 2,449,145 (29,851 ) Agency RMBS 759,255 (17,453 ) 1,172,313 (10,247 ) 1,931,568 (27,700 ) CMBS 31,607 (703 ) 348,943 (2,422 ) 380,550 (3,125 ) Non-Agency RMBS 8,029 (788 ) 4,197 (11 ) 12,226 (799 ) ABS 57,298 (570 ) 392,170 (1,424 ) 449,468 (1,994 ) Municipals 11,230 (269 ) 65,632 (703 ) 76,862 (972 ) Total fixed maturities $ 1,532,513 $ (44,352 ) $ 5,619,002 $ (46,521 ) $ 7,151,515 $ (90,873 ) Equity securities Common stocks $ — $ — $ 3,202 $ (590 ) $ 3,202 $ (590 ) Exchange-traded funds — — 12,323 (294 ) 12,323 (294 ) Bond mutual funds — — 12,184 (999 ) 12,184 (999 ) Total equity securities $ — $ — $ 27,709 $ (1,883 ) $ 27,709 $ (1,883 ) (1) Effective January 1, 2018, the Company adopted ASU No. 2016-01, which requires equity securities to be measured at fair value with changes in fair value recognized in net income therefore equity securities at fair value are excluded from the table above at December 31, 2018.
MORTGAGE LOANS NET OF VALUATION ALLOWANCE	The following table provides details of the Company's mortgage loans held-for-investment: December 31, 2018 December 31, 2017 Carrying value % of Total Carrying value % of Total Mortgage Loans held-for-investment: Commercial $ 298,650 100 % $ 325,062 100 % Total Mortgage Loans held-for-investment $ 298,650 100 % $ 325,062 100 %
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 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 % At December 31, 2017 Long/short equity funds $ 38,470 4 % Annually 60 days Multi-strategy funds 286,164 28 % Quarterly, Semi-annually 60-95 days Event-driven funds 39,177 4 % Annually 45 days Direct lending funds 250,681 25 % n/a n/a Private equity funds 68,812 7 % n/a n/a Real estate funds 50,009 5 % n/a n/a CLO-Equities 31,413 2 % n/a n/a Other privately held investments 46,430 5 % n/a n/a Overseas deposits 198,217 20 % n/a n/a Total other investments $ 1,009,373 100 % n/a – not applicable
NET INVESTMENT INCOME	Net investment income was derived from the following sources: Year ended December 31, 2018 2017 2016 Fixed maturities $ 356,273 $ 312,662 $ 305,459 Other investments 48,959 76,858 42,514 Equity securities 10,077 14,919 16,306 Mortgage loans 13,566 10,780 7,996 Cash and cash equivalents 27,566 10,057 9,209 Short-term investments 9,365 2,718 2,060 Gross investment income 465,806 427,994 383,544 Investment expenses (27,299 ) (27,189 ) (30,209 ) Net investment income $ 438,507 $ 400,805 $ 353,335
NET REALIZED INVESTMENT GAINS (LOSSES)	The following table provides an analysis of net investment gains (losses): Year ended December 31, 2018 2017 2016 Gross realized investment gains Fixed maturities and short-term investments $ 46,067 $ 72,046 $ 86,267 Equity securities 20,435 78,343 19,104 Gross realized investment gains 66,502 150,389 105,371 Gross realized investment losses Fixed maturities and short-term investments (142,153 ) (98,442 ) (134,460 ) Equity securities (3,389 ) (959 ) (16,155 ) Gross realized investment losses (145,542 ) (99,401 ) (150,615 ) Net OTTI charge recognized in net income (9,733 ) (14,493 ) (26,210 ) Change in fair value of investment derivatives (1) 5,445 (8,269 ) 10,929 Change in fair value of equity securities (2) (66,890 ) — — Net investment gains (losses) $ (150,218 ) $ 28,226 $ (60,525 ) (1) Refer to Note 8 'Derivative Instruments' (2) Effective January 1, 2018, the Company adopted ASU No. 2016-01. The change in fair value of equity securities is now recognized in net income.
OTTI RECOGNIZED IN EARNINGS BY ASSET CLASS	The following table summarizes the OTTI charge recognized in net income by asset class: Year ended December 31, 2018 2017 2016 Fixed maturities: Non-U.S. government $ 4,697 $ 8,187 $ 3,557 Corporate debt 4,995 6,306 20,093 Non-Agency CMBS 41 — — 9,733 14,493 23,650 Equity Securities Exchange-traded funds — — 2,560 — — 2,560 Total OTTI recognized in net income $ 9,733 $ 14,493 $ 26,210
ROLL FORWARD OF CREDIT LOSSES FOR WHICH A PORTION OF OTTI RECOGNIZED IN AOCI	The following table provides a roll forward of credit losses ("credit loss table") before income taxes, for which a component of the OTTI charge was recognized in AOCI: Year ended December 31, 2018 2017 Balance at beginning of period $ 1,494 $ 1,493 Credit impairments recognized on securities not previously impaired — — Additional credit impairments recognized on securities previously impaired 8 13 Change in timing of future cash flows on securities previously impaired — — Intent to sell of securities previously impaired — — Securities sold/redeemed/matured (992 ) (12 ) Balance at end of period $ 510 $ 1,494
RESTRICTED INVESTMENTS	The fair value of the Company's restricted investments and cash primarily relates to these items, as noted in the table below. At December 31, 2018 2017 Collateral in Trust for inter-company agreements $ 2,121,522 $ 3,310,180 Collateral for secured letter of credit facility 470,051 386,451 Funds at Lloyd's 1,307,945 1,192,717 Collateral in Trust for third party agreements 1,510,416 2,085,443 Securities on deposit with regulatory authorities 64,360 53,925 Total restricted investments $ 5,474,294 $ 7,028,716

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2018
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 Significant other observable 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 8) — 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 8) $ — $ 4,223 $ 10,299 $ — $ 14,522 Cash settled awards (refer to Note 16) — 20,648 — — 20,648 Total Liabilities $ — $ 24,871 $ 10,299 $ — $ 35,170 (1) Includes Long/short equity, Multi-strategy and Event-driven funds. Quoted prices in active markets Significant other observable Significant unobservable inputs (Level 3) Fair value based on NAV practical expedient Total fair value At December 31, 2017 Assets Fixed maturities U.S. government and agency $ 1,658,622 $ 53,847 $ — $ — $ 1,712,469 Non-U.S. government — 806,299 — — 806,299 Corporate debt — 5,244,969 52,897 — 5,297,866 Agency RMBS — 2,395,152 — — 2,395,152 CMBS — 777,728 — — 777,728 Non-Agency RMBS — 46,831 — — 46,831 ABS — 1,436,281 — — 1,436,281 Municipals — 149,380 — — 149,380 1,658,622 10,910,487 52,897 — 12,622,006 Equity securities Common stocks 25,658 — — — 25,658 Exchange-traded funds 427,633 — — — 427,633 Bond mutual funds — 182,220 — — 182,220 453,291 182,220 — — 635,511 Other investments Hedge funds (1) — — — 363,811 363,811 Direct lending funds — — — 250,681 250,681 Private equity funds — — — 68,812 68,812 Real estate funds — — — 50,009 50,009 Other privately held investments — — 46,430 — 46,430 CLO-Equities — — 31,413 — 31,413 Overseas deposits — 198,217 — — 198,217 — 198,217 77,843 733,313 1,009,373 Short-term investments — 83,661 — — 83,661 Other assets Derivative instruments (refer to Note 8) — 5,125 — — 5,125 Insurance-linked securities — — 25,090 — 25,090 Total Assets $ 2,111,913 $ 11,379,710 $ 155,830 $ 733,313 $ 14,380,766 Liabilities Derivative instruments (refer to Note 8) $ — $ 2,876 $ 11,510 $ — $ 14,386 Cash settled awards (refer to Note 16) — 21,535 — — 21,535 Total Liabilities $ — $ 24,411 $ 11,510 $ — $ 35,921 (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 December 31, 2018 of investments classified as Level 3 in the fair value hierarchy. Fair value Valuation technique Unobservable input Range Weighted average Other investments - CLO-Equities $ 21,271 Discounted cash flow Default rates 3.0% 3.0% Loss severity rate 35% 35% Collateral spreads 3.0% 3.0% Estimated maturity dates 7 years 7 years Other investments - Other privately held investments $ 44,518 Discounted cash flow Discount rate 3.0% - 8.0% 7.1% Derivatives - Other underwriting-related derivatives $ (10,299 ) Discounted cash flow Discount rate 2.6% 2.6% 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 table presents 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) Year ended December 31, 2018 Fixed maturities Corporate debt $ 52,897 $ 2,935 $ (4,279 ) $ (591 ) $ 6,343 $ 10,267 $ (7,446 ) $ (11,114 ) $ 49,012 $ — CMBS — 5,096 — — (145 ) 17,200 — (3,017 ) 19,134 — ABS — 1,979 — — (446 ) 17,000 — — 18,533 — 52,897 10,010 (4,279 ) (591 ) 5,752 44,467 (7,446 ) (14,131 ) 86,679 — Other investments Other privately held investments 46,430 — — (913 ) — 3,110 (4,109 ) — 44,518 (913 ) CLO-Equities 31,413 — — 6,627 — — — (16,769 ) 21,271 6,627 77,843 — — 5,714 — 3,110 (4,109 ) (16,769 ) 65,789 5,714 Other assets Derivative instruments — — — — — — — — — — Insurance-linked securities 25,090 — — (90 ) — — — (25,000 ) — — 25,090 — — (90 ) — — — (25,000 ) — — Total assets $ 155,830 $ 10,010 $ (4,279 ) $ 5,033 $ 5,752 $ 47,577 $ (11,555 ) $ (55,900 ) $ 152,468 $ 5,714 Other liabilities Derivative instruments 11,510 — — (1,211 ) — — — — 10,299 (1,211 ) Total liabilities $ 11,510 $ — $ — $ (1,211 ) $ — $ — $ — $ — $ 10,299 $ (1,211 ) Year ended December 31, 2017 Fixed maturities Corporate debt $ 75,875 $ 2,324 $ (2,721 ) $ (503 ) $ (1,524 ) $ 17,062 $ (22,903 ) $ (14,713 ) $ 52,897 $ — CMBS 3,061 — — — — — — (3,061 ) — — ABS 17,464 — (18,949 ) — 1,485 — — — — — 96,400 2,324 (21,670 ) (503 ) (39 ) 17,062 (22,903 ) (17,774 ) 52,897 — Other investments Other privately held investments 42,142 — — 1,584 — 2,704 — — 46,430 1,584 CLO-Equities 60,700 — — 2,558 — — — (31,845 ) 31,413 2,558 102,842 — — 4,142 — 2,704 — (31,845 ) 77,843 4,142 Other assets Derivative instruments 2,532 — — 653 — — — (3,185 ) — — Insurance-linked securities 25,023 — — 67 — — — — 25,090 67 27,555 — — 720 — — — (3,185 ) 25,090 67 Total assets $ 226,797 $ 2,324 $ (21,670 ) $ 4,359 $ (39 ) $ 19,766 $ (22,903 ) $ (52,804 ) $ 155,830 $ 4,209 Other liabilities Derivative instruments 6,500 — — 9,320 — 12,472 — (16,782 ) 11,510 (962 ) Total liabilities $ 6,500 $ — $ — $ 9,320 $ — $ 12,472 $ — $ (16,782 ) $ 11,510 $ (962 ) (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 table presents 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) Year ended December 31, 2018 Fixed maturities Corporate debt $ 52,897 $ 2,935 $ (4,279 ) $ (591 ) $ 6,343 $ 10,267 $ (7,446 ) $ (11,114 ) $ 49,012 $ — CMBS — 5,096 — — (145 ) 17,200 — (3,017 ) 19,134 — ABS — 1,979 — — (446 ) 17,000 — — 18,533 — 52,897 10,010 (4,279 ) (591 ) 5,752 44,467 (7,446 ) (14,131 ) 86,679 — Other investments Other privately held investments 46,430 — — (913 ) — 3,110 (4,109 ) — 44,518 (913 ) CLO-Equities 31,413 — — 6,627 — — — (16,769 ) 21,271 6,627 77,843 — — 5,714 — 3,110 (4,109 ) (16,769 ) 65,789 5,714 Other assets Derivative instruments — — — — — — — — — — Insurance-linked securities 25,090 — — (90 ) — — — (25,000 ) — — 25,090 — — (90 ) — — — (25,000 ) — — Total assets $ 155,830 $ 10,010 $ (4,279 ) $ 5,033 $ 5,752 $ 47,577 $ (11,555 ) $ (55,900 ) $ 152,468 $ 5,714 Other liabilities Derivative instruments 11,510 — — (1,211 ) — — — — 10,299 (1,211 ) Total liabilities $ 11,510 $ — $ — $ (1,211 ) $ — $ — $ — $ — $ 10,299 $ (1,211 ) Year ended December 31, 2017 Fixed maturities Corporate debt $ 75,875 $ 2,324 $ (2,721 ) $ (503 ) $ (1,524 ) $ 17,062 $ (22,903 ) $ (14,713 ) $ 52,897 $ — CMBS 3,061 — — — — — — (3,061 ) — — ABS 17,464 — (18,949 ) — 1,485 — — — — — 96,400 2,324 (21,670 ) (503 ) (39 ) 17,062 (22,903 ) (17,774 ) 52,897 — Other investments Other privately held investments 42,142 — — 1,584 — 2,704 — — 46,430 1,584 CLO-Equities 60,700 — — 2,558 — — — (31,845 ) 31,413 2,558 102,842 — — 4,142 — 2,704 — (31,845 ) 77,843 4,142 Other assets Derivative instruments 2,532 — — 653 — — — (3,185 ) — — Insurance-linked securities 25,023 — — 67 — — — — 25,090 67 27,555 — — 720 — — — (3,185 ) 25,090 67 Total assets $ 226,797 $ 2,324 $ (21,670 ) $ 4,359 $ (39 ) $ 19,766 $ (22,903 ) $ (52,804 ) $ 155,830 $ 4,209 Other liabilities Derivative instruments 6,500 — — 9,320 — 12,472 — (16,782 ) 11,510 (962 ) Total liabilities $ 6,500 $ — $ — $ 9,320 $ — $ 12,472 $ — $ (16,782 ) $ 11,510 $ (962 ) (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)	12 Months Ended
	Dec. 31, 2018
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. At December 31, 2018 At December 31, 2017 Derivative notional amount Asset derivative fair value (1) Liability derivative fair value (1) Derivative notional amount Asset derivative fair value (1) Liability derivative fair value (1) Relating to investment portfolio: Foreign exchange forward contracts $ 79,336 $ 262 $ 531 $ 137,422 $ 10 $ 619 Interest rate swaps 150,000 — 1,116 191,000 448 1,556 Relating to underwriting portfolio: Foreign exchange forward contracts 737,419 7,975 2,576 698,959 4,667 701 Other underwriting-related contracts 85,000 — 10,299 85,000 — 11,510 Total derivatives $ 8,237 $ 14,522 $ 5,125 $ 14,386 (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. December 31, 2018 December 31, 2017 Gross amounts Gross amounts offset Net amounts (1) Gross amounts Gross amounts offset Net amounts (1) Derivative assets $ 11,967 $ (3,730 ) $ 8,237 $ 8,178 $ (3,053 ) $ 5,125 Derivative liabilities $ 18,252 $ (3,730 ) $ 14,522 $ 17,439 $ (3,053 ) $ 14,386 (1) Net asset and liability derivatives are classified within other assets and other liabilities on 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. December 31, 2018 December 31, 2017 Gross amounts Gross amounts offset Net amounts (1) Gross amounts Gross amounts offset Net amounts (1) Derivative assets $ 11,967 $ (3,730 ) $ 8,237 $ 8,178 $ (3,053 ) $ 5,125 Derivative liabilities $ 18,252 $ (3,730 ) $ 14,522 $ 17,439 $ (3,053 ) $ 14,386 (1) Net asset and liability derivatives are classified within other assets and other liabilities on 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 income on derivative Amount of gain (loss) recognized in income on derivative 2018 2017 2016 Relating to investment portfolio: Foreign exchange forward contracts Net investment gains (losses) $ 3,446 $ (6,935 ) $ 10,929 Interest rate swaps Net investment gains (losses) 1,999 (1,334 ) — Relating to underwriting portfolio: Foreign exchange forward contracts Foreign exchange gains (losses) (3,509 ) 25,383 (8,179 ) Weather-related contracts Other insurance related income (losses) — (9,629 ) 4,910 Commodity contracts Other insurance related income (losses) — — (2,382 ) Other underwriting-related contracts Other insurance related income (losses) 2,384 1,476 — Total $ 4,320 $ 8,961 $ 5,278

RESERVE FOR LOSSES AND LOSS E_2

RESERVE FOR LOSSES AND LOSS EXPENSES (Tables)	12 Months Ended
	Dec. 31, 2018
Insurance Loss Reserves [Abstract]
SCHEDULE OF THE LINES OF BUSINESS CATEGORIES AND THE EXPECTED CLAIM TAILS	The tables below map the Company's lines 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 Actuarial Analysis
COMPONENTS OF RESERVE FOR LOSSES AND LOSS EXPENSES	Reserve for losses and loss expenses comprise the following: As of December 31, 2018 2017 Reserve for reported losses and loss expenses $ 4,626,204 $ 5,137,659 Reserve for losses incurred but not reported 7,654,565 7,859,894 Reserve for losses and loss expenses $ 12,280,769 $ 12,997,553
RECONCILIATION OF BEGINNING AND ENDING GROSS RESERVE FOR LOSSES AND LOSS EXPENSES AND NET RESERVE FOR UNPAID LOSSES AND LOSS EXPENSES	The table below provides a reconciliation of beginning and ending net reserves for unpaid losses and loss expenses for the years indicated: Year ended December 31, 2018 2017 2016 Gross reserve for losses and loss expenses, beginning of year $ 12,997,553 $ 9,697,827 $ 9,646,285 Less reinsurance recoverable on unpaid losses, beginning of year (3,159,514 ) (2,276,109 ) (2,031,309 ) Net reserve for unpaid losses and loss expenses, beginning of year 9,838,039 7,421,718 7,614,976 Net incurred losses and loss expenses related to: Current year 3,389,949 3,487,826 2,496,574 Prior years (199,662 ) (200,054 ) (292,377 ) 3,190,287 3,287,772 2,204,197 Net paid losses and loss expenses related to: Current year (724,199 ) (703,796 ) (428,153 ) Prior years (2,368,615 ) (1,880,882 ) (1,763,696 ) (3,092,814 ) (2,584,678 ) (2,191,849 ) Foreign exchange and other (1,156,412 ) 1,713,227 (205,606 ) Net reserve for unpaid losses and loss expenses, end of year 8,779,100 9,838,039 7,421,718 Reinsurance recoverable on unpaid losses, end of year 3,501,669 3,159,514 2,276,109 Gross reserve for losses and loss expenses, end of year $ 12,280,769 $ 12,997,553 $ 9,697,827
NET PRIOR YEAR RESERVE DEVELOPMENT BY SEGMENT	The following table presents prior year reserve development by segment: Insurance Reinsurance Total Year ended December 31, 2018 $ 92,806 $ 106,856 $ 199,662 Year ended December 31, 2017 60,459 139,595 200,054 Year ended December 31, 2016 48,978 243,399 292,377
NET INCURRED AND PAID CLAIMS DEVELOPMENT TABLES BY ACCIDENT YEAR	Insurance property and other Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected development on reported claims Cumulative number of reported claims Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 117,309 $ 99,079 $ 89,768 $ 82,460 $ 80,461 $ 78,269 $ 78,490 $ 78,150 $ 78,395 $ 77,338 $ 83 3,201 2010 175,012 155,032 147,426 122,111 116,562 115,635 115,316 114,866 113,767 867 4,422 2011 359,132 338,220 306,114 285,745 282,755 281,405 281,866 279,996 979 6,348 2012 391,646 399,473 381,746 361,476 357,267 351,673 350,827 8,992 29,931 2013 308,359 297,713 271,157 267,022 266,727 276,940 6,687 53,172 2014 360,130 354,219 343,333 327,389 326,100 5,917 62,444 2015 277,332 268,897 257,927 253,729 5,642 47,052 2016 349,152 376,458 367,362 12,290 92,867 2017 882,968 825,176 42,188 663,914 2018 712,082 187,391 730,832 Total $ 3,583,317 Insurance property and other Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance For the years ended December 31, Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 31,360 $ 60,085 $ 68,653 $ 72,499 $ 73,387 $ 74,453 $ 76,673 $ 76,980 $ 77,248 $ 77,252 2010 48,575 86,886 94,912 105,719 109,933 110,008 109,794 109,837 110,171 2011 84,811 192,892 249,162 271,451 270,309 269,994 270,666 270,946 2012 77,088 213,138 277,230 300,129 307,639 312,818 312,894 2013 75,214 197,898 236,405 247,393 258,435 261,266 2014 131,991 258,098 304,609 311,730 315,797 2015 98,366 201,166 225,593 239,989 2016 122,407 287,049 327,706 2017 251,358 625,027 2018 276,472 Total 2,817,520 All outstanding liabilities before 2009, net of reinsurance 5,862 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 771,659 Reinsurance professional lines Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected development on reported claims Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 211,420 $ 211,191 $ 215,827 $ 218,469 $ 208,338 $ 208,693 $ 193,803 $ 189,991 $ 180,862 $ 179,945 $ 4,495 2010 210,016 210,238 211,409 214,439 214,161 196,770 189,263 179,604 165,864 10,034 2011 201,457 201,735 202,815 211,459 208,828 207,946 200,168 177,163 22,132 2012 209,889 216,415 221,808 223,813 222,499 212,485 213,850 33,873 2013 209,538 214,624 215,544 213,765 213,142 205,586 67,043 2014 219,378 219,332 219,286 219,109 233,427 48,605 2015 212,030 212,150 214,310 225,003 84,299 2016 195,061 196,246 199,879 84,621 2017 155,211 155,892 109,070 2018 146,558 142,282 Total $ 1,903,167 Reinsurance professional lines Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance For the years ended December 31, Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 914 $ 8,588 $ 32,306 $ 63,066 $ 83,703 $ 108,373 $ 128,071 $ 138,247 $ 143,732 $ 150,811 2010 1,758 12,029 31,245 52,129 76,763 107,270 123,889 130,487 137,917 2011 1,510 11,825 30,273 57,182 84,776 102,938 119,643 129,920 2012 779 10,400 29,616 53,587 85,921 107,173 131,770 2013 1,062 12,070 30,495 64,966 81,641 104,883 2014 2,019 13,066 48,814 74,542 109,129 2015 3,134 13,505 41,524 79,270 2016 1,772 20,516 52,588 2017 2,814 14,918 2018 273 Total 911,479 All outstanding liabilities before 2009, net of reinsurance 47,397 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 1,039,085 Insurance marine Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected development on reported claims Cumulative number of reported claims Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 80,615 $ 74,181 $ 69,862 $ 64,477 $ 57,106 $ 54,906 $ 53,514 $ 52,400 $ 52,283 $ 50,735 $ 359 3,220 2010 68,528 70,394 66,389 53,388 51,483 48,650 47,249 45,543 45,125 643 3,196 2011 90,717 78,700 72,530 65,766 65,769 65,983 68,140 68,829 1,005 3,830 2012 89,639 82,648 68,715 70,855 71,823 74,445 72,585 12,055 4,134 2013 79,610 100,767 96,210 97,265 82,547 82,136 2,729 2,351 2014 59,558 44,463 48,481 44,392 45,980 5,454 2,157 2015 158,755 140,050 136,827 129,627 8,498 2,219 2016 86,264 78,779 76,743 12,819 2,795 2017 171,936 170,085 49,990 3,863 2018 178,709 113,414 3,250 Total $ 920,554 Insurance marine Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance For the years ended December 31, Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 17,394 $ 30,297 $ 39,674 $ 43,147 $ 45,159 $ 45,775 $ 48,321 $ 48,587 $ 48,920 $ 50,244 2010 18,029 28,631 33,298 42,364 45,194 45,976 46,940 43,346 43,433 2011 26,435 44,218 54,930 58,025 59,862 60,572 64,868 66,913 2012 10,711 38,545 44,800 49,523 50,331 52,724 54,721 2013 18,982 44,087 54,898 63,128 65,822 76,856 2014 6,349 15,172 26,838 26,924 35,987 2015 21,426 54,869 108,152 111,027 2016 12,486 31,981 57,745 2017 14,472 68,563 2018 23,016 Total 588,505 All outstanding liabilities before 2009, net of reinsurance 8,619 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 340,668 Insurance credit and political risk Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected development on reported claims Cumulative number of reported claims Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 248,083 $ 305,282 $ 326,024 $ 335,536 $ 334,965 $ 335,271 $ 335,291 $ 339,570 $ 339,534 $ 340,648 $ 3,600 24 2010 62,415 63,179 63,259 65,596 64,977 65,011 72,101 90,880 99,416 1,316 6 2011 58,154 48,665 47,706 48,361 48,333 45,036 33,604 27,899 268 4 2012 32,602 15,672 12,435 12,447 10,320 44 197 155 4 2013 26,439 25,684 9,759 9,880 14,941 14,065 5,759 1 2014 38,825 70,712 67,109 68,320 69,586 1,136 6 2015 30,329 30,368 27,513 26,001 2,703 2 2016 45,907 44,639 42,184 17,704 1 2017 36,563 34,631 28,083 3 2018 46,172 33,079 1 Total $ 700,799 Insurance credit and political risk Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance For the years ended December 31, Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 92,842 $ 344,652 $ 346,254 $ 346,221 $ 341,577 $ 345,521 $ 345,520 $ 345,567 $ 341,231 $ 340,785 2010 50,000 85,418 90,729 106,767 101,786 101,948 102,154 102,196 102,514 2011 32,788 37,205 27,636 27,636 27,636 27,636 27,631 27,631 2012 — — — — 38 39 42 2013 745 2,235 3,726 5,216 11,768 13,826 2014 1,924 39,952 61,108 57,855 57,855 2015 — 23,309 23,298 23,298 2016 — 24,445 24,479 2017 1,504 5,589 2018 4,294 Total 600,313 All outstanding liabilities before 2009, net of reinsurance (1,475 ) Liabilities for claims and claim adjustment expenses, net of reinsurance $ 99,011 Insurance aviation Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected development on reported claims Cumulative number of reported claims Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 17,468 $ 14,560 $ 18,752 $ 18,090 $ 16,743 $ 16,618 $ 15,437 $ 14,604 $ 14,330 $ 13,821 $ 41 1,659 2010 12,922 11,699 11,422 9,749 8,769 8,699 8,744 8,548 8,900 78 1,950 2011 17,723 15,390 12,779 9,552 8,422 7,275 7,242 7,203 205 2,145 2012 12,789 10,668 10,791 8,708 7,758 7,804 7,695 200 2,242 2013 15,651 16,327 15,199 15,243 15,618 15,502 292 2,320 2014 20,432 23,028 24,339 22,104 22,183 425 2,717 2015 29,761 28,479 30,363 30,135 1,480 3,484 2016 29,154 34,328 34,513 2,845 3,456 2017 56,565 63,295 7,676 3,452 2018 57,955 12,452 2,280 Total $ 261,202 Insurance aviation Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance For the years ended December 31, Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 2,081 $ 3,583 $ 7,026 $ 12,780 $ 13,902 $ 14,266 $ 14,203 $ 13,700 $ 13,665 $ 13,616 2010 1,037 4,131 6,312 6,886 7,551 7,670 8,113 8,221 8,423 2011 638 2,822 4,512 5,028 5,562 5,811 6,042 6,188 2012 953 2,858 4,147 5,941 6,822 7,146 7,263 2013 4,399 7,326 9,746 11,444 13,594 14,200 2014 3,987 8,019 11,687 14,167 14,824 2015 8,084 16,155 21,507 23,797 2016 10,407 20,113 27,120 2017 22,512 41,671 2018 21,058 Total 178,160 All outstanding liabilities before 2009, net of reinsurance 8,362 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 91,404 Reinsurance motor Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected development on reported claims Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 81,369 $ 79,515 $ 87,140 $ 89,057 $ 90,860 $ 92,158 $ 83,517 $ 77,943 $ 80,204 $ 77,829 $ 17,628 2010 98,704 105,669 106,092 104,993 99,061 93,919 84,535 81,228 78,575 19,993 2011 156,069 158,750 162,586 168,436 164,559 155,948 145,482 140,191 24,417 2012 178,052 167,788 156,460 149,100 144,164 134,768 131,690 22,562 2013 162,681 158,632 147,139 137,695 134,200 131,081 21,880 2014 182,625 182,555 177,575 174,457 169,776 9,307 2015 222,768 216,808 220,527 221,982 29,755 2016 245,899 261,369 263,168 43,569 2017 363,651 371,089 84,007 2018 357,187 172,384 Total $ 1,942,568 Reinsurance motor Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance For the years ended December 31, Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 2,709 $ 6,830 $ 8,012 $ 9,523 $ 12,933 $ 19,066 $ 21,368 $ 25,910 $ 29,144 $ 31,650 2010 7,075 11,951 17,066 20,387 23,554 27,766 30,977 32,015 33,083 2011 23,788 46,979 61,309 71,664 78,202 84,067 88,630 89,619 2012 29,162 52,736 67,254 76,875 83,232 87,244 89,492 2013 33,807 52,639 66,119 75,865 81,388 86,832 2014 43,325 73,572 92,721 100,607 110,562 2015 57,809 92,778 112,584 129,661 2016 60,829 104,342 127,970 2017 72,226 133,842 2018 83,854 Total 916,565 All outstanding liabilities before 2009, net of reinsurance 146,464 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 1,172,467 Insurance professional lines Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected development on reported claims Cumulative number of reported claims Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 240,092 $ 243,522 $ 243,978 $ 244,466 $ 253,979 $ 236,657 $ 236,751 $ 212,994 $ 220,524 $ 224,778 $ 13,640 5,889 2010 230,353 235,610 233,407 204,744 181,917 157,921 179,517 167,038 186,340 18,897 5,690 2011 312,805 314,466 331,800 324,739 329,318 342,598 351,247 351,747 33,877 7,215 2012 327,590 372,782 374,315 373,306 360,596 362,606 351,498 50,067 8,300 2013 382,270 394,548 394,461 361,785 351,330 353,112 70,914 9,409 2014 408,103 407,688 418,164 389,610 369,129 111,975 9,766 2015 374,209 373,747 380,265 355,300 127,537 10,379 2016 346,289 349,223 355,601 152,080 11,632 2017 375,397 393,443 256,260 12,903 2018 357,398 304,926 12,392 Total $ 3,298,346 Insurance professional lines Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance For the years ended December 31, Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 1,657 $ 20,619 $ 44,065 $ 68,690 $ 96,631 $ 106,985 $ 126,542 $ 165,088 $ 177,492 $ 184,577 2010 7,850 27,815 53,458 72,554 88,585 99,082 109,668 114,710 136,252 2011 7,399 32,812 73,940 107,980 165,206 237,804 282,907 294,043 2012 7,801 41,021 99,486 183,295 229,932 252,937 272,298 2013 17,633 72,784 128,858 174,759 211,931 241,074 2014 23,450 70,266 129,160 191,437 222,692 2015 19,976 67,313 137,145 168,627 2016 15,846 70,947 146,342 2017 20,812 71,495 2018 19,098 Total 1,756,498 All outstanding liabilities before 2009, net of reinsurance 45,848 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 1,587,696 Reinsurance credit and surety Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected development on reported claims Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 143,398 $ 122,111 $ 105,827 $ 105,062 $ 104,236 $ 98,958 $ 95,726 $ 95,321 $ 93,688 $ 92,519 $ 1,304 2010 119,152 100,047 93,548 90,657 86,528 79,047 77,732 75,716 74,430 4,092 2011 121,471 107,811 105,955 112,964 111,019 102,529 100,718 100,146 5,770 2012 160,109 148,566 151,141 148,363 140,000 131,963 128,323 8,830 2013 165,413 153,616 144,472 140,589 136,402 125,112 8,083 2014 135,732 136,346 143,515 139,857 128,404 11,280 2015 160,837 166,951 161,789 157,612 26,891 2016 142,245 141,780 149,054 38,746 2017 135,750 134,063 38,299 2018 111,969 53,762 Total $ 1,201,632 Reinsurance credit and surety Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance For the years ended December 31, Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 32,479 $ 76,440 $ 78,378 $ 80,574 $ 84,401 $ 87,047 $ 87,180 $ 87,089 $ 87,594 $ 87,238 2010 28,218 48,715 59,776 60,452 62,144 63,279 64,710 65,724 66,023 2011 22,449 54,012 70,850 78,477 83,036 85,242 87,571 89,004 2012 49,631 85,701 99,705 105,551 109,073 110,844 112,118 2013 32,447 77,059 91,902 98,517 106,202 108,062 2014 35,570 61,440 86,539 95,675 103,272 2015 32,935 82,174 100,464 117,594 2016 42,069 73,603 92,788 2017 37,311 74,341 2018 38,975 Total 889,415 All outstanding liabilities before 2009, net of reinsurance 13,274 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 325,491 Reinsurance liability Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected development on reported claims Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 172,680 $ 174,121 $ 180,945 $ 178,149 $ 184,811 $ 204,531 $ 192,287 $ 178,260 $ 168,917 $ 175,770 $ 13,563 2010 171,634 170,784 182,515 183,056 201,329 190,959 181,938 165,990 159,156 14,137 2011 172,431 172,399 174,124 191,761 197,871 194,715 193,830 191,962 24,450 2012 167,290 163,625 167,887 172,491 173,645 171,121 164,357 27,789 2013 172,784 176,465 182,428 184,467 184,147 177,273 53,822 2014 200,203 203,136 204,871 200,819 199,583 75,626 2015 214,942 215,273 216,201 215,997 97,353 2016 240,411 246,024 251,087 131,475 2017 277,034 270,564 176,854 2018 264,450 209,612 Total $ 2,070,199 Reinsurance liability Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance For the years ended December 31, Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 1,704 $ 17,102 $ 44,473 $ 56,623 $ 73,229 $ 103,662 $ 122,704 $ 127,009 $ 132,996 $ 136,539 2010 2,481 17,654 46,201 62,291 83,826 97,457 108,770 119,693 128,399 2011 5,189 21,273 39,981 70,102 92,466 112,328 123,387 135,625 2012 3,541 12,798 28,388 58,735 78,190 101,115 115,571 2013 5,969 22,236 52,327 69,052 88,264 102,588 2014 7,083 28,663 48,415 70,143 89,436 2015 7,271 27,457 54,524 80,865 2016 11,861 37,688 69,526 2017 12,424 42,092 2018 19,305 Total 919,946 All outstanding liabilities before 2009, net of reinsurance 54,315 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 1,204,568 Reinsurance property and other Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected development on reported claims Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 340,527 $ 284,210 $ 246,047 $ 232,639 $ 223,245 $ 204,560 $ 198,498 $ 200,422 $ 197,779 $ 198,189 $ 1,722 2010 612,614 600,219 569,357 582,855 585,247 579,065 571,120 569,043 568,179 5,532 2011 1,109,682 1,116,708 1,124,792 1,083,492 1,066,384 1,040,470 1,038,726 1,040,130 10,579 2012 555,241 523,310 507,750 477,145 461,255 456,334 457,703 8,446 2013 578,645 560,227 529,463 509,179 503,203 502,642 5,140 2014 540,406 560,478 534,229 521,797 519,967 43,358 2015 477,608 463,996 459,017 453,628 14,117 2016 614,940 633,597 620,702 30,481 2017 1,076,458 1,080,319 123,562 2018 880,269 492,589 Total $ 6,321,728 Reinsurance property and other Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance For the years ended December 31, Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 56,420 $ 129,397 $ 160,284 $ 178,388 $ 188,919 $ 188,240 $ 191,046 $ 192,728 $ 191,900 $ 190,174 2010 116,143 310,268 403,566 435,155 481,009 510,061 534,893 540,616 542,909 2011 251,538 587,390 793,972 893,041 922,456 995,795 1,010,611 1,013,191 2012 122,688 294,436 367,055 389,461 404,019 413,789 415,831 2013 107,085 324,443 440,804 470,990 480,712 482,114 2014 101,937 352,361 434,354 451,890 458,032 2015 71,244 265,569 368,360 400,615 2016 126,404 375,374 519,223 2017 252,008 722,835 2018 194,154 Total 4,939,078 All outstanding liabilities before 2009, net of reinsurance 11,126 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 1,393,776 Insurance liability Incurred claims and allocated claim adjustment expenses, net of reinsurance At December 31, 2018 For the years ended December 31, Total of incurred-but-not-reported liabilities plus expected development on reported claims Cumulative number of reported claims Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 61,469 $ 64,017 $ 67,410 $ 67,869 $ 75,883 $ 83,281 $ 101,179 $ 98,384 $ 98,999 $ 97,964 $ 9,450 4,093 2010 79,407 94,220 98,635 98,112 99,570 98,061 105,119 104,258 103,906 11,742 3,670 2011 72,586 75,329 83,118 87,059 85,242 83,730 82,127 82,625 17,357 3,222 2012 70,861 70,631 73,281 70,770 68,180 75,341 72,514 23,236 2,837 2013 92,150 94,178 94,253 87,498 93,216 95,632 21,345 3,520 2014 106,148 122,643 128,524 130,021 131,539 31,126 4,614 2015 127,319 125,819 136,305 164,036 52,818 5,975 2016 123,243 129,139 128,172 73,747 6,628 2017 161,211 165,061 107,070 5,842 2018 166,659 141,099 3,725 Total $ 1,208,108 Insurance liability Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance For the years ended December 31, Accident year 2009 unaudited 2010 unaudited 2011 unaudited 2012 unaudited 2013 unaudited 2014 unaudited 2015 unaudited 2016 unaudited 2017 unaudited 2018 2009 $ 726 $ 4,646 $ 13,305 $ 26,754 $ 31,865 $ 41,322 $ 44,105 $ 83,991 $ 84,975 $ 86,231 2010 1,030 15,966 30,788 53,581 61,029 66,114 71,788 86,433 87,981 2011 2,761 10,540 20,190 38,376 46,074 54,996 60,263 62,152 2012 1,630 5,514 15,411 30,145 37,139 42,745 46,545 2013 2,360 23,281 33,320 42,051 60,017 66,976 2014 1,415 18,645 49,840 71,617 84,397 2015 5,438 22,308 39,557 92,557 2016 6,318 23,286 36,406 2017 5,404 29,529 2018 8,704 Total 601,478 All outstanding liabilities before 2009, net of reinsurance 43,840 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 650,470
AVERAGE ANNUAL PERCENTAGE PAYOUT OF INCURRED CLAIMS BY AGE, NET OF REINSURANCE	Insurance property and other Average annual percentage payout of incurred claims by age, net of reinsurance (unaudited) Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 34.5% 40.2% 13.2% 5.8% 2.0% 0.8% 0.7% 0.2% 0.3% —% Reinsurance professional lines Average annual percentage payout of incurred claims by age, net of reinsurance (unaudited) Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 0.9% 5.9% 12.1% 14.4% 13.3% 12.7% 10.5% 5.2% 3.8% 3.9% Reinsurance credit and surety Average annual percentage payout of incurred claims by age, net of reinsurance (unaudited) Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 29.9% 30.0% 12.6% 5.5% 4.3% 1.9% 1.3% 0.9% 0.5% (0.4)% Insurance credit and political risk Average annual percentage payout of incurred claims by age, net of reinsurance (unaudited) Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 21.7% 38.9% 1.6% 3.1% 9.9% 3.3% 0.4% —% (0.5)% (0.1)% Reinsurance liability Average annual percentage payout of incurred claims by age, net of reinsurance (unaudited) Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 3.4% 9.2% 13.1% 12.0% 11.2% 11.6% 8.1% 5.2% 4.5% 2.0% Insurance professional lines Average annual percentage payout of incurred claims by age, net of reinsurance (unaudited) Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 4.1% 11.8% 15.7% 13.4% 11.6% 9.1% 8.2% 7.7% 8.6% 3.2% Reinsurance property and other Average annual percentage payout of incurred claims by age, net of reinsurance (unaudited) Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 22.2% 39.9% 19.1% 6.5% 3.8% 2.9% 1.9% 0.7% —% (0.9)% Insurance aviation Average annual percentage payout of incurred claims by age, net of reinsurance (unaudited) Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 22.3% 24.8% 20.0% 15.5% 8.6% 3.1% 2.3% (0.1)% 1.0% (0.4)% Insurance marine Average annual percentage payout of incurred claims by age, net of reinsurance (unaudited) Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 21.9% 27.3% 20.8% 7.2% 6.2% 4.1% 4.0% (1.5)% 0.5% 2.6% Insurance liability Average annual percentage payout of incurred claims by age, net of reinsurance (unaudited) Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 2.8% 11.8% 12.9% 19.4% 10.0% 8.1% 5.0% 19.0% 1.3% 1.3% Reinsurance motor Average annual percentage payout of incurred claims by age, net of reinsurance (unaudited) Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 19.5% 14.1% 8.6% 5.8% 4.7% 4.9% 3.0% 2.6% 2.8% 3.2%
RECONCILIATION OF DEVELOPMENT TABLES TO CONSOLIDATED BALANCE SHEET	The following table reconciles the reserves for loss and loss expenses at December 31, 2018 included in the loss development tables to the reserves for loss and loss expenses reported in the consolidated balance sheet: Reconciliation of the disclosure of incurred and paid claims development to the liability for unpaid claims and claim adjustment expenses At December 31, 2018 Net outstanding liabilities Reinsurance recoverable on unpaid claims Gross outstanding liabilities Insurance segment Property and other $ 771,659 $ 482,207 $ 1,253,866 Marine 340,668 187,164 527,832 Aviation 91,404 14,310 105,714 Credit and political risk 99,011 24,536 123,547 Professional Lines 1,587,696 1,005,316 2,593,012 Liability 650,470 978,719 1,629,189 Total insurance segment 3,540,908 2,692,252 6,233,160 Reinsurance segment Property and other 1,393,776 435,671 1,829,447 Credit and surety 325,491 36,180 361,671 Professional lines 1,039,085 81,608 1,120,693 Motor 1,172,467 128,575 1,301,042 Liability 1,204,568 127,383 1,331,951 Total reinsurance segment 5,135,387 809,417 5,944,804 Total $ 8,676,295 $ 3,501,669 12,177,964 Unallocated claims adjustment expenses 145,768 Foreign exchange and other (1) 53,695 (Ceded)/assumed reserves related to retroactive transactions (96,658 ) Total liability for unpaid claims and claims adjustment expense $ 12,280,769 (1) Non-U.S. dollar denominated loss data is converted to U.S dollar at the rates of exchange in effect at the balance sheet date for material underlying currencies. Fluctuations in currency exchange rates cause material shifts in loss development. Reserves for losses and loss expenses, disclosed in the consolidated balance sheets, are also revalued using the exchange rate at the balance sheet date.

REINSURANCE (Tables)

REINSURANCE (Tables)	12 Months Ended
	Dec. 31, 2018
Reinsurance Disclosures [Abstract]
BREAKDOWN OF GROSS AND NET PREMIUMS WRITTEN AND EARNED	Gross and net premiums written and earned were as follows: Year ended December 31, 2018 2017 2016 Premiums written Premiums earned Premiums written Premiums earned Premiums written Premiums earned Gross $ 6,910,065 $ 6,882,217 $ 5,556,273 $ 5,616,234 $ 4,970,208 $ 4,762,394 Ceded (2,251,103 ) (2,090,722 ) (1,529,130 ) (1,467,474 ) (1,217,234 ) (1,056,769 ) Net $ 4,658,962 $ 4,791,495 $ 4,027,143 $ 4,148,760 $ 3,752,974 $ 3,705,625

DEBT AND FINANCING ARRANGEMEN_2

DEBT AND FINANCING ARRANGEMENTS (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Scheduled debt maturity	The scheduled maturity of the Company's aggregate amount of its debt obligation on its consolidated balance sheet at December 31, 2018 is shown in the following table: Year ended December 31, 2019 $ 250,000 2020 500,000 2021 — 2022 — 2023 — After 2023 600,000 Unamortized discount and debt issuance expenses (8,039 ) Total senior notes and notes payable $ 1,341,961

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
FUTURE MINIMUM LEASE PAYMENTS UNDER OPERATING LEASES	Future minimum lease payments are 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

EARNINGS PER COMMON SHARE (Tabl

EARNINGS PER COMMON SHARE (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
BASIC AND DILUTED EARNINGS PER COMMON SHARE	The following table presents a comparison of earnings (loss) per common share and earnings (loss) per diluted common share: At and year ended December 31, 2018 2017 2016 Earnings (loss) per common share Net income (loss) $ 43,021 $ (368,969 ) $ 513,368 Less: Preferred share dividends 42,625 46,810 46,597 Less: Loss on repurchase of preferred shares — — 1,309 Net income (loss) available (attributable) to common shareholders $ 396 $ (415,779 ) $ 465,462 Weighted average common shares outstanding 83,501 84,108 90,772 Earnings (loss) per common share $ — $ (4.94 ) $ 5.13 Earnings (loss) per diluted common share Net income (loss) available (attributable) to common shareholders $ 396 $ (415,779 ) $ 465,462 Weighted average common shares outstanding 83,501 84,108 90,772 Share-based compensation plans (1) 506 — 775 Weighted average diluted common shares outstanding (1) 84,007 84,108 91,547 Earnings (loss) per diluted common share $ — $ (4.94 ) $ 5.08 Weighted average anti-dilutive shares excluded from the dilutive computation 245 702 170 (1) Due to the net loss incurred in the year ended December 31, 2017, all the share equivalents were anti-dilutive.

SHAREHOLDERS' EQUITY (Tables)

SHAREHOLDERS' EQUITY (Tables)	12 Months Ended
	Dec. 31, 2018
Stockholders' Equity Note [Abstract]
COMMON SHARES ISSUED AND OUTSTANDING	The following table presents changes in common shares issued and outstanding, excluding restricted stock units related to the Company's share-based compensation plans (refer to Note 16 ' Share-Based Compensation' ): Year ended December 31, 2018 2017 2016 Shares issued, balance at beginning of year 176,580 176,580 176,240 Shares issued — — 340 Total shares issued at end of year 176,580 176,580 176,580 Treasury shares, balance at beginning of year (93,419 ) (90,139 ) (80,174 ) Shares repurchased (200 ) (4,288 ) (10,508 ) Shares reissued 625 1,008 543 Total treasury shares at end of year (92,994 ) (93,419 ) (90,139 ) Total shares outstanding 83,586 83,161 86,441
SHARE REPURCHASES	The following table presents common shares repurchased from shares held in treasury: Year ended December 31, 2018 2017 2016 In the open market: Total shares (1) — 3,932 10,241 Total cost $ — $ 261,180 $ 557,476 Average price per share (2) $ — $ 66.43 $ 54.44 From employees: (3) Total shares 200 356 267 Total cost $ 10,080 $ 24,678 $ 14,329 Average price per share (2) $ 50.40 $ 69.36 $ 53.74 Total shares repurchased: Total shares 200 4,288 10,508 Total cost $ 10,080 $ 285,858 $ 571,805 Average price per share (2) $ 50.40 $ 66.67 $ 54.42 (1) Amounts in 2016 include common shares acquired under the accelerated share repurchase program of 1,358,380 (see below for more detail). (2) Calculated using whole numbers. (3) Shares are repurchased from employees to satisfy withholding tax liabilities that arise upon the vesting of restricted stock awards and restricted stock units. Share repurchases from employees are excluded from the authorized share repurchase plan noted above.

SHARE-BASED COMPENSATION (Table

SHARE-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
RECONCILIATION OF BEGINNING AND ENDING BALANCE OF NONVESTED RESTRICTED STOCK (INCLUDING RSUS) TO BE SETTLED IN SHARES AND CASH	a) Share-Settled Awards The following table provides an activity summary of the Company's share-settled RSUs: Share-Settled PSUs Share-Settled Service Based RSUs 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 - December 31, 2016 283 $ 51.27 1,593 $ 48.88 Granted 87 64.58 733 61.94 Vested (2) (119 ) 49.14 (889 ) 47.48 Forfeited (21 ) 55.00 (82 ) 54.89 Nonvested restricted stock - December 31, 2017 230 57.08 1,355 57.09 Granted 104 48.89 737 49.36 Vested (87 ) 54.71 (539 ) 54.51 Forfeited (15 ) 53.80 (142 ) 55.36 Nonvested restricted stock - December 31, 2018 232 $ 54.54 1,411 $ 54.12 (1) Fair value is based on the closing price of the Company's common shares on the grant date. (2) Share-settled restricted stock units that vested during the year ended December 31, 2017 included 313,391 service based restricted stock units which were granted in 2014 and were subject to a three year cliff vesting period. b) Cash-Settled Awards The following table provides an activity summary of the Company's cash-settled RSUs: Cash-Settled PSUs Cash-Settled Service based RSUs Number of restricted stock units Number of restricted stock units Nonvested restricted stock units - December 31, 2016 68 1,392 Granted 15 432 Vested (1) (38 ) (763 ) Forfeited (3 ) (73 ) Nonvested restricted stock units - December 31, 2017 42 988 Granted — 473 Vested (12 ) (390 ) Forfeited (3 ) (139 ) Nonvested restricted stock units - December 31, 2018 27 932 (1) Cash-settled restricted stock units that vested during the year ended December 31, 2017 included 307,556 service based restricted stock units which were granted in 2014 and were subject to a three year cliff vesting period.

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
SCHEDULE OF INCOME TAX EXPENSE AND NET TAX ASSETS	An analysis of income tax expense and net tax assets is shown in the following table: Year ended December 31, 2018 2017 2016 Current income tax expense (benefit) U.S. $ (5,401 ) $ (6,207 ) $ 606 Europe 10,409 10,249 7,451 Other 51 — — Deferred income tax expense (benefit) U.S. 15,288 18,495 (1,829 ) Europe (49,833 ) (30,079 ) 112 Total income tax expense (benefit) $ (29,486 ) $ (7,542 ) $ 6,340 Net current tax receivables (payables) $ 9,683 $ (639 ) $ 3,540 Net deferred tax assets 39,775 4,438 103,313 Net tax assets $ 49,458 $ 3,799 $ 106,853
SCHEDULE OF DEFERRED TAX ASSETS AND LIABILITIES	The significant components of deferred tax assets and liabilities were as follows: At December 31, 2018 2017 Deferred tax assets: Discounting of net reserves for losses and loss expenses $ 37,440 $ 27,804 Unearned premiums 40,447 25,188 Net unrealized investments losses 11,438 — Operating and capital loss carryforwards (1) 83,850 53,095 Accruals not currently deductible 32,589 31,560 Tax credits 8,672 29,929 Other deferred tax assets 9,195 15,047 Deferred tax assets before valuation allowance 223,631 182,623 Valuation allowance (18,955 ) (16,157 ) Deferred tax assets net of valuation allowance 204,676 166,466 Deferred tax liabilities: Deferred acquisition costs (39,745 ) (24,249 ) Net unrealized investments gains — (8,033 ) Amortization of VOBA, intangible assets and goodwill (49,097 ) (85,296 ) Equalization reserves (22,069 ) (23,274 ) Other deferred tax liabilities (53,990 ) (21,176 ) Deferred tax liabilities (164,901 ) (162,028 ) Net deferred tax assets $ 39,775 $ 4,438 (1) At December 31, 2018 and 2017, the total operating loss carryforwards includes Lloyd's deferred year of account losses of $68 million and $19 million , respectively.
SUMMARY OF TAX CREDITS	Total operating and capital loss carryforwards and tax credits are summarized in the following table: At December 31, 2018 2017 Operating and Capital Loss Carryforwards (1) Singapore (branch) operating loss carryforward $ 79,445 $ 77,467 U.K. operating loss carryforward (2) 413,504 126,839 Ireland operating loss carryforward 12,756 — U.S. operating loss carryforward 15,062 115,236 Ireland capital loss carryforward 716 716 Tax Credits (1) Ireland foreign tax credit $ 2,248 $ 3,566 U.S. alternative minimum tax credit (3) 6,026 12,052 U.K. tax credit 398 14,310 (1) All operating and capital loss carryforwards and tax credits can be carried forward indefinitely with the exception of the U.S. net operating loss, which will expire in 2037. (2) At December 31, 2018 and 2017, the U.K. operating loss carryforward includes Lloyd's deferred year of account losses of $403 million and $113 million , respectively. (3) As a result of U.S. tax reform, all alternative minimum tax credits will be refunded by tax year 2021.
SUMMARY OF OPERATING AND CAPITAL LOSS CARRYFORWARDS	Total operating and capital loss carryforwards and tax credits are summarized in the following table: At December 31, 2018 2017 Operating and Capital Loss Carryforwards (1) Singapore (branch) operating loss carryforward $ 79,445 $ 77,467 U.K. operating loss carryforward (2) 413,504 126,839 Ireland operating loss carryforward 12,756 — U.S. operating loss carryforward 15,062 115,236 Ireland capital loss carryforward 716 716 Tax Credits (1) Ireland foreign tax credit $ 2,248 $ 3,566 U.S. alternative minimum tax credit (3) 6,026 12,052 U.K. tax credit 398 14,310 (1) All operating and capital loss carryforwards and tax credits can be carried forward indefinitely with the exception of the U.S. net operating loss, which will expire in 2037. (2) At December 31, 2018 and 2017, the U.K. operating loss carryforward includes Lloyd's deferred year of account losses of $403 million and $113 million , respectively. (3) As a result of U.S. tax reform, all alternative minimum tax credits will be refunded by tax year 2021.
VALUATION ALLOWANCE ROLL FORWARD	An analysis of the movement in the Company's valuation allowance is shown in the following table: At December 31, 2018 2017 Income tax expense: Valuation allowance - beginning of year $ 16,157 $ 41,100 Operating loss carryforwards 198 (27,116 ) Foreign tax credit (1,359 ) 267 U.K. branch assets and other foreign rate differentials (205 ) 1,006 U.S. alternative minimum tax credits (900 ) 900 Valuation allowance - end of year $ 13,891 $ 16,157 Accumulated other comprehensive income: Valuation allowance - beginning of year — — Change in investment - related items 5,064 — Valuation allowance - end of year 5,064 — Total valuation allowance - end of year $ 18,955 $ 16,157
EFFECTIVE TAX RATE RECONCILIATION	The following table presents the distribution of income before income taxes between domestic and foreign jurisdictions as well as a reconciliation of the actual income tax rate to the amount computed by applying the effective tax rate of 0% under Bermuda law to income before income taxes: Year ended December 31, 2018 2017 2016 Income (loss) before income taxes Bermuda (domestic) $ 181,597 $ (188,420 ) $ 469,306 Foreign (168,062 ) (188,091 ) 50,402 Total income before income taxes $ 13,535 $ (376,511 ) $ 519,708 Reconciliation of effective tax rate (% of income before income taxes) Expected tax rate 0.0 % 0.0 % 0.0 % Foreign taxes at local expected rates: U.S. 65.7 % 6.6 % (0.6 )% Europe (289.7 )% 5.8 % 1.5 % Other — % 0.3 % — % Valuation allowance (13.4 )% — % 0.2 % Net tax exempt income (3.3 )% 0.1 % (0.2 )% Change in U.S. enacted tax rate — % (11.1 )% — % Change in European enacted tax rate 16.9 % — % — % Other 5.9 % 0.3 % 0.3 % Actual tax rate (217.9 )% 2.0 % 1.2 %

OTHER COMPREHENSIVE INCOME (L_2

OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
TAX EFFECTS ALLOCATED TO EACH COMPONENT OF OTHER COMPREHENSIVE INCOME (LOSS)	The following table presents the tax effects allocated to each component of other comprehensive income (loss): Before tax amount Tax (expense) benefit Net of tax amount Year ended December 31, 2018 Available for sale investments: Unrealized investment gains (losses) arising during the year $ (297,259 ) $ 5,528 $ (291,731 ) Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income 105,730 (4,828 ) 100,902 Unrealized investment gains (losses) arising during the year, net of reclassification adjustment (1) (191,529 ) 700 (190,829 ) Non-credit portion of OTTI losses — — — Foreign currency translation adjustment (11,165 ) — (11,165 ) Total other comprehensive income (loss), net of tax $ (202,694 ) $ 700 $ (201,994 ) Year ended December 31, 2017 Available for sale investments: Unrealized investment gains (losses) arising during the year $ 211,151 $ (5,732 ) $ 205,419 Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income (33,892 ) 758 (33,134 ) Unrealized investment gains (losses) arising during the year, net of reclassification adjustment 177,259 (4,974 ) 172,285 Non-credit portion of OTTI losses — — — Foreign currency translation adjustment 41,938 — 41,938 Total other comprehensive income (loss), net of tax $ 219,197 $ (4,974 ) $ 214,223 Year ended December 31, 2016 Available for sale investments: Unrealized investment gains (losses) arising during the year $ 10,165 $ (5,093 ) $ 5,072 Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income 60,423 1,767 62,190 Unrealized investment gains (losses) arising during the year, net of reclassification adjustment 70,588 (3,326 ) 67,262 Non-credit portion of OTTI losses — — — Foreign currency translation adjustment (638 ) — (638 ) Total other comprehensive income (loss), net of tax $ 69,950 $ (3,326 ) $ 66,624 (1) Effective January 1, 2018, the Company adopted ASU No. 2016-01. The adoption of this guidance resulted in a cumulative adjustment to reclassify unrealized investment gains on equity securities from accumulated other comprehensive income to retained earnings. Refer to Item 8, Note 2 ' Basis of Presentation and Significant Accounting Policies ' to the consolidated financial statements for additional information.
RECLASSIFICATIONS OUT OF AOCI INTO NET INCOME AVAILABLE TO COMMON SHAREHOLDERS	The following table presents reclassification amounts from accumulated other comprehensive income ("AOCI") to net income (loss) available (attributable) to common shareholders: Amount reclassified from AOCI (1) Details about AOCI components Consolidated statement of operations line item that includes reclassification Year ended December 31, 2018 2017 2016 Unrealized investment gains (losses) on available for sale investments Other realized investment gains (losses) $ (95,997 ) $ 48,385 $ (34,213 ) OTTI losses (9,733 ) (14,493 ) (26,210 ) Total before tax (105,730 ) 33,892 (60,423 ) Income tax (expense) benefit 4,828 (758 ) (1,767 ) Net of tax $ (100,902 ) $ 33,134 $ (62,190 ) Foreign currency translation adjustments Foreign exchange loss $ — $ (24,149 ) $ — Income tax (expense) benefit — — — Net of tax $ — $ (24,149 ) $ — (1) Amounts in parentheses are charges to net income (loss) available (attributable) to common shareholders

STATUTORY FINANCIAL INFORMATI_2

STATUTORY FINANCIAL INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2018
STATUTORY FINANCIAL INFORMATION [Abstract]
STATUTORY CAPITAL AND SURPLUS BY JURISDICTION	At December 31, 2018 and 2017 , the statutory capital and surplus in each of the Company's most significant regulatory jurisdictions are shown in the following table: Bermuda Ireland U.S. At December 31, 2018 2017 2018 2017 2018 2017 Required statutory capital and surplus $ 1,470,375 $ 1,800,064 $ 637,226 $ 613,923 $ 489,560 $ 488,560 Available statutory capital and surplus $ 3,513,342 $ 3,641,279 $ 896,868 $ 906,512 $ 1,668,847 $ 1,511,480

UNAUDITED CONDENSED QUARTERLY_2

UNAUDITED CONDENSED QUARTERLY FINANCIAL DATA (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
UNAUDITED SUMMARY OF QUARTERLY FINANCIAL RESULTS	An unaudited summary of quarterly financial results is shown in the following table: Quarters ended Mar 31 Jun 30 Sep 30 Dec 31 2018 Net premiums earned $ 1,167,402 $ 1,185,548 $ 1,224,075 $ 1,214,469 Net investment income 100,999 109,960 114,421 113,128 Net investment losses (14,830 ) (45,093 ) (17,628 ) (72,667 ) Underwriting income (loss) 143,737 115,726 59,026 (194,664 ) Net income (loss) available (attributable) to common shareholders 62,546 92,858 43,439 (198,448 ) Earnings (loss) per common share $ 0.75 $ 1.11 $ 0.52 $ (2.37 ) Earnings (loss) per diluted common share $ 0.75 $ 1.11 $ 0.52 $ (2.37 ) 2017 Net premiums earned $ 938,703 $ 981,431 $ 1,017,131 $ 1,211,495 Net investment income 98,664 106,063 95,169 100,908 Net investment gains (losses) (25,050 ) (4,392 ) 14,632 43,038 Underwriting income (loss) 16,385 57,012 (512,853 ) 26,130 Net income (loss) available (attributable) to common shareholders 5,014 85,030 (467,740 ) (38,081 ) Earnings (loss) per common share $ 0.06 $ 1.01 $ (5.61 ) $ (0.46 ) Earnings (loss) per diluted common share $ 0.06 $ 1.01 $ (5.61 ) $ (0.46 ) (1) During the three months ended March 31, June 30, September 30 and December 31, 2018, the Company recognized transaction and reorganization expenses of $13 million , $19 million , $16 million and $19 million , respectively, 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 accident and health business, together with other initiatives designed to increase the Company's efficiency and enhance the Company's profitability while delivering a customer-centric operating model. During the three months ended September 30 and December 31, 2017, the Company recognized transaction and reorganization expenses of $6 million and $21 million , respectively. (2) During the three months ended March 31, June 30, September 30 and December 31, 2018, the Company recognized amortization of VOBA of $57 million , $53 million , $39 million , $23 million , respectively, related to the acquisition of Novae. During the three months ended December 31, 2017, the Company recognized amortization of VOBA of $50 million . Refer to Item 8, Note 3 and Note 5 to the Consolidated Financial Statements ' Business Combinations ' and ' Goodwill and Intangible Assets ' for further details. (3) During the three months ended December 31, 2017, the Company recognized tax expense of $42 million due to the revaluation of net deferred tax asset pursuant to the U.S. Tax Reform. Refer to Item 8, Note 18 to the Consolidated Financial Statements 'Income Taxes' for further details.

HISTORY (Details)

HISTORY (Details)	2 Months Ended
	Feb. 28, 2019	Oct. 02, 2017
Novae
Business Acquisition [Line Items]
Interests acquired		100.00%
Subsequent Event | Axis Corporate Capital UK Limited
Business Acquisition [Line Items]
Capital support, percentage	70.00%
Subsequent Event | Novae Corporate Underwriting Limited
Business Acquisition [Line Items]
Capital support, percentage	30.00%

SIGNIFICANT ACCOUNTING POLICES

SIGNIFICANT ACCOUNTING POLICES (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gross premiums written									$ (6,910,065)	$ (5,556,273)	$ (4,970,208)
Underwriting income (loss)	$ 194,664	$ (59,026)	$ (115,726)	$ (143,737)	$ (26,130)	$ 512,853	$ (57,012)	$ (16,385)
Revenue									32,000
Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred income tax expense (benefit)										13,000
Unrealized gains on equity securities, net of tax, in AOCI					70,000					70,000
Accounting Standards Update 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in tax rate, deferred tax liability, provisional income tax benefit										2,000
Retained earnings | Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption of ASU					(69,604)					(69,604)	0		$ 0
Retained earnings | Accounting Standards Update 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption of ASU					$ 2,106					2,106	0		$ 0
Accounting Standards Update 2018-11 | Scenario, Forecast
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, liability												$ 149,000
Operating Segments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gross premiums written									(6,910,065)	(5,556,273)	(4,970,208)
Underwriting income (loss)									(123,827)	413,326	(279,073)
Operating Segments | Insurance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gross premiums written									(3,797,592)	(2,814,918)	(2,432,475)
Underwriting income (loss)									(77,298)	241,642	(22,630)
Operating Segments | Insurance | Restatement Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gross premiums written										313,000	288,000
Underwriting income (loss)										14,000	15,000
Operating Segments | Reinsurance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gross premiums written									(3,112,473)	(2,741,355)	(2,537,733)
Underwriting income (loss)									$ (46,529)	171,684	(256,443)
Operating Segments | Reinsurance | Restatement Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gross premiums written										(313,000)	(288,000)
Underwriting income (loss)										$ (14,000)	$ (15,000)

BUSINESS COMBINATIONS - Narrati

BUSINESS COMBINATIONS - Narrative (Details) - USD ($) $ in Thousands	Oct. 02, 2017	Apr. 01, 2017	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 06, 2017
Business Acquisition [Line Items]
Transaction and reorganization expenses			$ 19,000	$ 16,000	$ 19,000	$ 13,000	$ 21,000	$ 6,000
Goodwill			$ 102,003				$ 102,003		$ 102,003	$ 102,003
Bargain purchase gain									0	15,044	$ 0
Novae
Business Acquisition [Line Items]
Interests acquired	100.00%
Total purchase price paid	$ 616,926
Transaction and reorganization expenses									$ 26,000	$ 27,000
Goodwill	54,047
Finite lived other intangible assets	385,000
Value of business acquired - definite lived intangible asset	256,942
Indefinite lived intangible assets	94,748
Total liabilities assumed	3,342,912
Novae | Distribution networks
Business Acquisition [Line Items]
Finite lived other intangible assets	$ 128,463
Aviabel
Business Acquisition [Line Items]
Interests acquired		100.00%
Assets		$ 182,000
Total liabilities assumed		79,000
Bargain purchase gain		$ 15,000
Contessa Limited
Business Acquisition [Line Items]
Interests acquired												100.00%
Goodwill												$ 1,000

BUSINESS COMBINATIONS - Assets

BUSINESS COMBINATIONS - Assets acquired and liabilities assumed assets acquired and liabilities assumed (Details) - USD ($) $ in Thousands	Oct. 02, 2017	Dec. 31, 2018	Dec. 31, 2017
Fair value of identifiable intangible assets:
Goodwill		$ 102,003	$ 102,003
Novae
Business Acquisition [Line Items]
Total purchase price paid	$ 616,926
Assets
Investments	1,733,611
Cash and cash equivalents	191,337
Insurance and reinsurance premium balances receivable	472,180
Reinsurance recoverable on unpaid and paid losses	787,907
Prepaid reinsurance premiums	197,907
Other assets	42,696
Total assets acquired	3,425,638
Liabilities
Reserve for losses and loss expenses	2,125,634
Unearned premiums	717,442
Insurance and reinsurance balances payable	273,405
Notes payable	101,846
Other liabilities	124,585
Total liabilities assumed	3,342,912
Fair value of identifiable intangible assets:
Value of business acquired - definite lived intangible asset	256,942
Finite lived other intangible assets	128,463
Indefinite lived intangible assets	94,748
Goodwill	$ 54,047

BUSINESS COMBINATIONS - Intangi

BUSINESS COMBINATIONS - Intangible assets (Details) - Novae $ in Thousands	Oct. 02, 2017USD ($)
Business Acquisition [Line Items]
Indefinite lived intangible assets	$ 94,748
Finite lived other intangible assets	385,000
Identifiable intangible assets at October 2, 2017	223,211
Coverholders
Business Acquisition [Line Items]
Finite lived other intangible assets	$ 63,565
Economic useful life	12 years
Large brokers
Business Acquisition [Line Items]
Finite lived other intangible assets	$ 46,641
Economic useful life	15 years
Small & Mid-sized Enterprise (SME) brokers
Business Acquisition [Line Items]
Finite lived other intangible assets	$ 14,126
Economic useful life	12 years
Managing General Agent (MGA) Contract
Business Acquisition [Line Items]
Finite lived other intangible assets	$ 4,131
Economic useful life	7 years
Distribution networks
Business Acquisition [Line Items]
Finite lived other intangible assets	$ 128,463

BUSINESS COMBINATIONS - Financi

BUSINESS COMBINATIONS - Financial results (Details) - USD ($) $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2017

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Business Acquisition [Line Items]

Net premiums earned

$ 1,214,469

$ 1,224,075

$ 1,185,548

$ 1,167,402

$ 1,211,495

$ 1,017,131

$ 981,431

$ 938,703

$ 4,791,495

$ 4,148,760

$ 3,705,625

Novae

Business Acquisition [Line Items]

Net premiums earned

$ 140,635

Total revenue

191,929

Total expenses

(197,895)

Net income

$ (5,966)

BUSINESS COMBINATIONS - Pro for

BUSINESS COMBINATIONS - Pro forma (Details) - Novae - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Net premiums earned	$ 4,728,700	$ 4,560,800
Net income	$ (468,400)	$ 532,500

SEGMENT INFORMATION - Segment r

SEGMENT INFORMATION - Segment results (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2018USD ($)reportable_segment	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Segment Information [Line Items]
Number of reportable segments | reportable_segment									2
Gross premiums written									$ 6,910,065	$ 5,556,273	$ 4,970,208
Net premiums written									4,658,962	4,027,143	3,752,974
Net premiums earned	$ 1,214,469	$ 1,224,075	$ 1,185,548	$ 1,167,402	$ 1,211,495	$ 1,017,131	$ 981,431	$ 938,703	4,791,495	4,148,760	3,705,625
Other insurance related income (losses)									10,622	(1,240)	7,222
Net losses and loss expenses									(3,190,287)	(3,287,772)	(2,204,197)
Acquisition costs									(968,835)	(823,591)	(746,876)
General and administrative expenses									(627,389)	(579,428)	(602,717)
Underwriting income (loss)	(194,664)	59,026	115,726	143,737	26,130	(512,853)	57,012	16,385
Net investment income	113,128	114,421	109,960	100,999	100,908	95,169	106,063	98,664	438,507	400,805	353,335
Net investment losses	(72,667)	(17,628)	(45,093)	(14,830)	43,038	$ 14,632	$ (4,392)	$ (25,050)	(150,218)	28,226	(60,525)
Foreign exchange gains									29,165	(134,737)	121,295
Interest expense and financing costs									(67,432)	(54,811)	(51,360)
Bargain purchase gain									0	15,044	0
Transaction and reorganization expenses									(66,940)	(26,718)	0
Amortization of value of business acquired	(23,000)	$ (39,000)	$ (53,000)	$ (57,000)	(50,000)				(172,332)	(50,104)	0
Amortization of intangible assets									(13,814)	(2,543)	0
Income (loss) before income taxes and interest in income (loss) of equity method investments									12,542	(368,109)	521,802
Total intangible assets	379,285				566,828				379,285	566,828	85,049	$ 86,858
Operating Segments
Segment Information [Line Items]
Gross premiums written									6,910,065	5,556,273	4,970,208
Net premiums written									4,658,962	4,027,143	3,752,974
Net premiums earned									4,791,495	4,148,760	3,705,625
Other insurance related income (losses)									10,622	(1,240)	7,222
Net losses and loss expenses									(3,190,287)	(3,287,772)	(2,204,197)
Acquisition costs									(968,835)	(823,591)	(746,876)
General and administrative expenses									(519,168)	(449,483)	(482,701)
Underwriting income (loss)									$ 123,827	$ (413,326)	$ 279,073
Net loss and loss expense ratio									66.60%	79.20%	59.50%
Acquisition cost ratio									20.20%	19.90%	20.20%
General and administrative expense ratio									13.10%	14.00%	16.20%
Combined ratio									99.90%	113.10%	95.90%
Total intangible assets	379,285				566,828				$ 379,285	$ 566,828	$ 85,049
Operating Segments | Insurance
Segment Information [Line Items]
Gross premiums written									3,797,592	2,814,918	2,432,475
Net premiums written									2,324,747	1,775,825	1,519,559
Net premiums earned									2,362,606	1,816,438	1,534,282
Other insurance related income (losses)									3,460	2,944	89
Net losses and loss expenses									(1,494,323)	(1,465,427)	(977,771)
Acquisition costs									(399,193)	(270,229)	(206,619)
General and administrative expenses									(395,252)	(325,368)	(327,351)
Underwriting income (loss)									$ 77,298	$ (241,642)	$ 22,630
Net loss and loss expense ratio									63.20%	80.70%	63.70%
Acquisition cost ratio									16.90%	14.90%	13.50%
General and administrative expense ratio									16.80%	17.90%	21.30%
Combined ratio									96.90%	113.50%	98.50%
Total intangible assets	379,285				566,828				$ 379,285	$ 566,828	$ 85,049
Operating Segments | Reinsurance
Segment Information [Line Items]
Gross premiums written									3,112,473	2,741,355	2,537,733
Net premiums written									2,334,215	2,251,318	2,233,415
Net premiums earned									2,428,889	2,332,322	2,171,343
Other insurance related income (losses)									7,162	(4,184)	7,133
Net losses and loss expenses									(1,695,964)	(1,822,345)	(1,226,426)
Acquisition costs									(569,642)	(553,362)	(540,257)
General and administrative expenses									(123,916)	(124,115)	(155,350)
Underwriting income (loss)									$ 46,529	$ (171,684)	$ 256,443
Net loss and loss expense ratio									69.80%	78.10%	56.50%
Acquisition cost ratio									23.50%	23.70%	24.90%
General and administrative expense ratio									5.10%	5.30%	7.10%
Combined ratio									98.40%	107.10%	88.50%
Total intangible assets	$ 0				$ 0				$ 0	$ 0	$ 0
Corporate
Segment Information [Line Items]
General and administrative expenses									(108,221)	(129,945)	(120,016)
Significant Reconciling Items
Segment Information [Line Items]
Net investment income									438,507	400,805	353,335
Net investment losses									(150,218)	28,226	(60,525)
Foreign exchange gains									29,165	(134,737)	121,295
Interest expense and financing costs									(67,432)	(54,811)	$ (51,360)
Bargain purchase gain										15,044
Transaction and reorganization expenses									(66,940)	(26,718)
Amortization of value of business acquired									(172,332)	(50,104)
Amortization of intangible assets									$ (13,814)	$ (2,543)

SEGMENT INFORMATION - Gross pre

SEGMENT INFORMATION - Gross premiums written (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	$ 6,910,065	$ 5,556,273	$ 4,970,208
Bermuda
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	606,452	529,425	465,980
Ireland
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	1,805,882	1,569,956	1,650,229
U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	2,811,537	2,814,933	2,562,789
Lloyd's of London
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	$ 1,686,194	$ 641,959	$ 291,210

SEGMENT INFORMATION - Net premi

SEGMENT INFORMATION - Net premiums earned (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue from External Customer [Line Items]
Net premiums earned	$ 1,214,469	$ 1,224,075	$ 1,185,548	$ 1,167,402	$ 1,211,495	$ 1,017,131	$ 981,431	$ 938,703	$ 4,791,495	$ 4,148,760	$ 3,705,625
Operating Segments
Revenue from External Customer [Line Items]
Net premiums earned									4,791,495	4,148,760	3,705,625
Operating Segments | Insurance
Revenue from External Customer [Line Items]
Net premiums earned									2,362,606	1,816,438	1,534,282
Operating Segments | Insurance | Property
Revenue from External Customer [Line Items]
Net premiums earned									796,945	543,342	426,918
Operating Segments | Insurance | Marine
Revenue from External Customer [Line Items]
Net premiums earned									300,944	181,533	150,046
Operating Segments | Insurance | Terrorism
Revenue from External Customer [Line Items]
Net premiums earned									49,150	36,084	33,279
Operating Segments | Insurance | Aviation
Revenue from External Customer [Line Items]
Net premiums earned									74,203	75,107	44,980
Operating Segments | Insurance | Credit and political risk
Revenue from External Customer [Line Items]
Net premiums earned									102,825	56,432	57,964
Operating Segments | Insurance | Professional lines
Revenue from External Customer [Line Items]
Net premiums earned									570,241	519,759	510,806
Operating Segments | Insurance | Liability
Revenue from External Customer [Line Items]
Net premiums earned									229,373	188,770	169,182
Operating Segments | Insurance | Accident and health
Revenue from External Customer [Line Items]
Net premiums earned									207,777	199,121	141,107
Operating Segments | Insurance | Discontinued lines - Novae
Revenue from External Customer [Line Items]
Net premiums earned									31,148	16,290	0
Operating Segments | Reinsurance
Revenue from External Customer [Line Items]
Net premiums earned									2,428,889	2,332,322	2,171,343
Operating Segments | Reinsurance | Catastrophe
Revenue from External Customer [Line Items]
Net premiums earned									250,016	209,470	199,825
Operating Segments | Reinsurance | Property
Revenue from External Customer [Line Items]
Net premiums earned									317,038	304,376	272,403
Operating Segments | Reinsurance | Professional lines
Revenue from External Customer [Line Items]
Net premiums earned									220,687	226,622	289,868
Operating Segments | Reinsurance | Credit and surety
Revenue from External Customer [Line Items]
Net premiums earned									250,276	244,186	252,210
Operating Segments | Reinsurance | Motor
Revenue from External Customer [Line Items]
Net premiums earned									438,693	371,501	318,863
Operating Segments | Reinsurance | Liability
Revenue from External Customer [Line Items]
Net premiums earned									363,292	351,940	332,479
Operating Segments | Reinsurance | Agriculture
Revenue from External Customer [Line Items]
Net premiums earned									176,435	195,391	142,501
Operating Segments | Reinsurance | Engineering
Revenue from External Customer [Line Items]
Net premiums earned									67,932	66,291	62,833
Operating Segments | Reinsurance | Marine and other
Revenue from External Customer [Line Items]
Net premiums earned									35,570	64,449	57,322
Operating Segments | Reinsurance | Accident and health
Revenue from External Customer [Line Items]
Net premiums earned									299,813	289,925	243,039
Operating Segments | Reinsurance | Discontinued lines - Novae
Revenue from External Customer [Line Items]
Net premiums earned									$ 9,137	$ 8,171	$ 0

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Oct. 02, 2017	Sep. 06, 2017
Finite-Lived Intangible Assets [Line Items]
Impairment charges	$ 3,500,000
Excess purchase price over fair value of net assets acquired assigned to goodwill	102,003,000	$ 102,003,000
Goodwill and Intangible Asset Impairment	$ 3,500,000	$ 0	$ 0
Minimum
Finite-Lived Intangible Assets [Line Items]
Economic useful life	1 year
Maximum
Finite-Lived Intangible Assets [Line Items]
Economic useful life	14 years
Novae
Finite-Lived Intangible Assets [Line Items]
Finite lived other intangible assets				$ 385,000,000
Value of business acquired - definite lived intangible asset				256,942,000
Indefinite lived intangible assets				94,748,000
Excess purchase price over fair value of net assets acquired assigned to goodwill				54,047,000
Contessa Limited
Finite-Lived Intangible Assets [Line Items]
Excess purchase price over fair value of net assets acquired assigned to goodwill					$ 1,000,000
Distribution networks | Novae
Finite-Lived Intangible Assets [Line Items]
Finite lived other intangible assets				$ 128,463,000

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS - Analysis of goodwill and intangible assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill
Goodwill, gross		$ 97,092,000	$ 42,237,000	$ 42,237,000
Accumulated translation adjustment		4,911,000	4,911,000	4,911,000
Goodwill, net of accumulated translation adjustment	$ 102,003,000	102,003,000	47,148,000	47,148,000
Acquired during the year		54,855,000
Intangible assets with an indefinite life
Gross amount		120,784,000	26,036,000	26,036,000
Accumulated translation adjustment		0	0	0
Intangible assets with an indefinite life, net	120,784,000	120,784,000	26,036,000
Acquired during the year		94,748,000
Intangible assets with a finite life
Gross amount		410,575,000	23,030,000	23,030,000
Accumulated amortization		(66,534,000)	(11,165,000)	(9,356,000)
Accumulated translation adjustment		0	0	0
Intangible assets with a finite life, net	156,498,000	344,041,000	11,865,000	13,674,000
Acquired during the year		387,545,000
Amortization	(184,043,000)	(55,369,000)	(1,809,000)
Impairment charge	(3,500,000)
Total
Gross amount		628,451,000	91,303,000	91,303,000
Accumulated amortization		(66,534,000)	(11,165,000)	(9,356,000)
Accumulated translation adjustment		4,911,000	4,911,000	4,911,000
Goodwill and intangible assets net balance	379,285,000	566,828,000	85,049,000	$ 86,858,000
Acquired during the year		537,148,000
Amortization	(184,043,000)	(55,369,000)	(1,809,000)
Impairment charge	$ (3,500,000)	$ 0	$ 0

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS - Gross amount and accumulated amortization by category (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross amount	$ 531,359	$ 531,359
Accumulated amortization and impairment	(254,077)	(66,534)
Total intangible assets	277,282	464,825
Impairment charges	3,500
Customer lists, trademark and non-compete - Media Pro
Finite-Lived Intangible Assets [Line Items]
Gross amount	9,700	9,700
Accumulated amortization and impairment	(9,598)	(9,244)
Total intangible assets	102	456
Customer relationships and customers lists - Ternian
Finite-Lived Intangible Assets [Line Items]
Gross amount	13,330	13,330
Accumulated amortization and impairment	(4,999)	(3,666)
Total intangible assets	8,331	9,664
Coverholders
Finite-Lived Intangible Assets [Line Items]
Gross amount	63,565	63,565
Accumulated amortization and impairment	(6,622)	(1,324)
Total intangible assets	56,943	62,241
Large brokers
Finite-Lived Intangible Assets [Line Items]
Gross amount	46,641	46,641
Accumulated amortization and impairment	(3,888)	(777)
Total intangible assets	42,753	45,864
SME brokers
Finite-Lived Intangible Assets [Line Items]
Gross amount	14,126	14,126
Accumulated amortization and impairment	(1,471)	(294)
Total intangible assets	12,655	13,832
MGA contract(1)
Finite-Lived Intangible Assets [Line Items]
Gross amount	4,131	4,131
Accumulated amortization and impairment	(4,131)	(148)
Total intangible assets	0	3,983
Impairment charges	3,500
U.S. state licenses
Finite-Lived Intangible Assets [Line Items]
Gross amount	26,036	26,036
Total intangible assets	26,036	26,036
Syndicate capacity
Finite-Lived Intangible Assets [Line Items]
Gross amount	94,748	94,748
Total intangible assets	94,748	94,748
Avaibel | VOBA - Novae
Finite-Lived Intangible Assets [Line Items]
Gross amount	2,140	2,140
Accumulated amortization and impairment	(2,140)	(977)
Total intangible assets	0	1,163
Novae | VOBA - Novae
Finite-Lived Intangible Assets [Line Items]
Gross amount	256,942	256,942
Accumulated amortization and impairment	(221,228)	(50,104)
Total intangible assets	$ 35,714	$ 206,838

GOODWILL AND INTANGIBLE ASSET_5

GOODWILL AND INTANGIBLE ASSETS - Estimated amortization expense (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
VOBA
2,019	$ 26,722
2,020	5,139
2,021	3,853
2,022	0
2,023	0
2024 and thereafter	0
Value of business acquired	35,714	$ 206,838
Intangible assets
2,019	11,017
2,020	10,916
2,021	10,916
2,022	10,916
2,023	10,916
2024 and thereafter	66,103
Total	120,784
Indefinite lived intangible assets	120,784	120,784	$ 26,036	$ 26,036
Intangible assets, net	241,568	257,987
Total
2,019	37,739
2,020	16,055
2,021	14,769
2,022	10,916
2,023	10,916
2024 and thereafter	66,103
Total remaining amortization expense	156,498
Total intangible assets	$ 277,282	$ 464,825

INVESTMENTS - Amortized cost or

INVESTMENTS - Amortized cost or cost and fair values (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fixed maturities
Amortized cost	$ 11,616,312	$ 12,611,219
Gross unrealized gains	33,874	101,660
Gross unrealized losses	(214,839)	(90,873)
Fair value	11,435,347	12,622,006
Non-credit OTTI in AOCI	(857)	(853)
U.S. government and agency
Fixed maturities
Amortized cost	1,520,142	1,727,643
Gross unrealized gains	4,232	1,735
Gross unrealized losses	(8,677)	(16,909)
Fair value	1,515,697	1,712,469
Non-credit OTTI in AOCI	0	0
Non-U.S. government
Fixed maturities
Amortized cost	507,550	798,582
Gross unrealized gains	1,586	17,240
Gross unrealized losses	(16,120)	(9,523)
Fair value	493,016	806,299
Non-credit OTTI in AOCI	0	0
Corporate debt
Fixed maturities
Amortized cost	4,990,279	5,265,795
Gross unrealized gains	15,086	61,922
Gross unrealized losses	(128,444)	(29,851)
Fair value	4,876,921	5,297,866
Non-credit OTTI in AOCI	0	0
Agency RMBS
Fixed maturities
Amortized cost	1,666,684	2,414,720
Gross unrealized gains	6,508	8,132
Gross unrealized losses	(29,884)	(27,700)
Fair value	1,643,308	2,395,152
Non-credit OTTI in AOCI	0	0
CMBS
Fixed maturities
Amortized cost	1,103,507	776,715
Gross unrealized gains	2,818	4,138
Gross unrealized losses	(13,795)	(3,125)
Fair value	1,092,530	777,728
Non-credit OTTI in AOCI	0	0
Non-Agency RMBS
Fixed maturities
Amortized cost	40,732	45,713
Gross unrealized gains	1,237	1,917
Gross unrealized losses	(1,282)	(799)
Fair value	40,687	46,831
Non-credit OTTI in AOCI	(857)	(853)
ABS
Fixed maturities
Amortized cost	1,651,350	1,432,884
Gross unrealized gains	1,493	5,391
Gross unrealized losses	(15,240)	(1,994)
Fair value	1,637,603	1,436,281
Non-credit OTTI in AOCI	0	0
Municipals
Fixed maturities
Amortized cost	136,068	149,167
Gross unrealized gains	914	1,185
Gross unrealized losses	(1,397)	(972)
Fair value	135,585	149,380
Non-credit OTTI in AOCI	$ 0	$ 0

INVESTMENTS - Equity securities

INVESTMENTS - Equity securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Debt and Equity Securities, FV-NI [Line Items]
Cost	$ 365,905	$ 552,867
Gross unrealized gains	33,610	84,527
Gross unrealized losses	(17,882)	(1,883)
Fair value	381,633	635,511
Common stocks
Debt and Equity Securities, FV-NI [Line Items]
Cost	790	22,836
Gross unrealized gains	112	3,412
Gross unrealized losses	(375)	(590)
Fair value	527	25,658
Exchange-traded funds
Debt and Equity Securities, FV-NI [Line Items]
Cost	213,420	356,252
Gross unrealized gains	33,498	71,675
Gross unrealized losses	(10,079)	(294)
Fair value	236,839	427,633
Bond mutual funds
Debt and Equity Securities, FV-NI [Line Items]
Cost	151,695	173,779
Gross unrealized gains	0	9,440
Gross unrealized losses	(7,428)	(999)
Fair value	$ 144,267	$ 182,220

INVESTMENTS - Contractual matur

INVESTMENTS - Contractual maturities of fixed maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Amortized cost
Due in one year or less	$ 430,390	$ 486,659
Due after one year through five years	4,751,064	4,906,207
Due after five years through ten years	1,762,452	2,338,964
Due after ten years	210,133	209,357
Total fixed maturities with a single maturity date (amortized cost)	7,154,039	7,941,187
Total	11,616,312	12,611,219
Fair value
Due in one year or less	426,142	484,663
Due after one year through five years	4,691,263	4,912,189
Due after five years through ten years	1,697,737	2,350,433
Due after ten years	206,077	218,729
Total fixed maturities with a single maturity date (fair value)	7,021,219	7,966,014
Fair value	$ 11,435,347	$ 12,622,006
% of Total fair value
Due in one year or less	3.70%	3.80%
Due after one year through five years	41.00%	38.90%
Due after five years through ten years	14.80%	18.60%
Due after ten years	1.80%	1.70%
Fixed maturities with a single maturity date (% of total fair value)	61.30%	63.00%
Total	100.00%	100.00%
Agency RMBS
Amortized cost
Fixed maturities without a single maturity date	$ 1,666,684	$ 2,414,720
Total	1,666,684	2,414,720
Fair value
Fixed maturities without a single maturity date (fair value)	1,643,308	2,395,152
Fair value	$ 1,643,308	$ 2,395,152
% of Total fair value
Fixed maturities without a single maturity date (% of total fair value)	14.40%	19.00%
CMBS
Amortized cost
Fixed maturities without a single maturity date	$ 1,103,507	$ 776,715
Total	1,103,507	776,715
Fair value
Fixed maturities without a single maturity date (fair value)	1,092,530	777,728
Fair value	$ 1,092,530	$ 777,728
% of Total fair value
Fixed maturities without a single maturity date (% of total fair value)	9.60%	6.20%
Non-Agency RMBS
Amortized cost
Fixed maturities without a single maturity date	$ 40,732	$ 45,713
Total	40,732	45,713
Fair value
Fixed maturities without a single maturity date (fair value)	40,687	46,831
Fair value	$ 40,687	$ 46,831
% of Total fair value
Fixed maturities without a single maturity date (% of total fair value)	0.40%	0.40%
ABS
Amortized cost
Fixed maturities without a single maturity date	$ 1,651,350	$ 1,432,884
Total	1,651,350	1,432,884
Fair value
Fixed maturities without a single maturity date (fair value)	1,637,603	1,436,281
Fair value	$ 1,637,603	$ 1,436,281
% of Total fair value
Fixed maturities without a single maturity date (% of total fair value)	14.30%	11.40%

INVESTMENTS - Gross unrealized

INVESTMENTS - Gross unrealized losses (Details) $ in Thousands	Dec. 31, 2018USD ($)security	Dec. 31, 2017USD ($)security
Fixed maturities
Total Unrealized Losses	$ (215,000)	$ (91,000)
Fixed maturities
Fixed maturities
Fair Value - 12 months or greater	3,569,519	1,532,513
Unrealized Losses - 12 months or greater	(114,561)	(44,352)
Fair Value - Less than 12 months	4,917,951	5,619,002
Unrealized Losses - Less than 12 months	(100,278)	(46,521)
Total Fair Value	8,487,470	7,151,515
Total Unrealized Losses	(214,839)	(90,873)
Equity securities
Fair Value - 12 months or greater	$ 3,570,000	$ 1,533,000
Unrealized loss position, number of positions | security	3,599	2,424
Continuous unrealized loss position, 12 months or longer, number of positions | security	1,656	627
Fixed maturities | Below Investment Grade or Not Rated
Fixed maturities
Total Unrealized Losses	$ (49,000)	$ (7,000)
U.S. government and agency
Fixed maturities
Fair Value - 12 months or greater	374,030	194,916
Unrealized Losses - 12 months or greater	(7,659)	(5,963)
Fair Value - Less than 12 months	424,439	1,389,792
Unrealized Losses - Less than 12 months	(1,018)	(10,946)
Total Fair Value	798,469	1,584,708
Total Unrealized Losses	(8,677)	(16,909)
Non-U.S. government
Fixed maturities
Fair Value - 12 months or greater	44,339	62,878
Unrealized Losses - 12 months or greater	(2,004)	(6,806)
Fair Value - Less than 12 months	303,376	204,110
Unrealized Losses - Less than 12 months	(14,116)	(2,717)
Total Fair Value	347,715	266,988
Total Unrealized Losses	(16,120)	(9,523)
Corporate debt
Fixed maturities
Fair Value - 12 months or greater	1,439,378	407,300
Unrealized Losses - 12 months or greater	(58,915)	(11,800)
Fair Value - Less than 12 months	2,547,135	2,041,845
Unrealized Losses - Less than 12 months	(69,529)	(18,051)
Total Fair Value	3,986,513	2,449,145
Total Unrealized Losses	(128,444)	(29,851)
Agency RMBS
Fixed maturities
Fair Value - 12 months or greater	940,645	759,255
Unrealized Losses - 12 months or greater	(29,255)	(17,453)
Fair Value - Less than 12 months	117,181	1,172,313
Unrealized Losses - Less than 12 months	(629)	(10,247)
Total Fair Value	1,057,826	1,931,568
Total Unrealized Losses	(29,884)	(27,700)
CMBS
Fixed maturities
Fair Value - 12 months or greater	455,582	31,607
Unrealized Losses - 12 months or greater	(11,430)	(703)
Fair Value - Less than 12 months	353,802	348,943
Unrealized Losses - Less than 12 months	(2,365)	(2,422)
Total Fair Value	809,384	380,550
Total Unrealized Losses	(13,795)	(3,125)
Non-Agency RMBS
Fixed maturities
Fair Value - 12 months or greater	9,494	8,029
Unrealized Losses - 12 months or greater	(1,170)	(788)
Fair Value - Less than 12 months	11,432	4,197
Unrealized Losses - Less than 12 months	(112)	(11)
Total Fair Value	20,926	12,226
Total Unrealized Losses	(1,282)	(799)
ABS
Fixed maturities
Fair Value - 12 months or greater	237,237	57,298
Unrealized Losses - 12 months or greater	(2,755)	(570)
Fair Value - Less than 12 months	1,150,692	392,170
Unrealized Losses - Less than 12 months	(12,485)	(1,424)
Total Fair Value	1,387,929	449,468
Total Unrealized Losses	(15,240)	(1,994)
Municipals
Fixed maturities
Fair Value - 12 months or greater	68,814	11,230
Unrealized Losses - 12 months or greater	(1,373)	(269)
Fair Value - Less than 12 months	9,894	65,632
Unrealized Losses - Less than 12 months	(24)	(703)
Total Fair Value	78,708	76,862
Total Unrealized Losses	$ (1,397)	(972)
Equity securities
Equity securities
Fair Value - 12 months or greater		0
Unrealized Losses - 12 months or greater		0
Fair Value - Less than 12 months		27,709
Unrealized Losses - less than 12 months		(1,883)
Total Fair Value		27,709
Total Unrealized Losses		(1,883)
Common stocks
Equity securities
Fair Value - 12 months or greater		0
Unrealized Losses - 12 months or greater		0
Fair Value - Less than 12 months		3,202
Unrealized Losses - less than 12 months		(590)
Total Fair Value		3,202
Total Unrealized Losses		(590)
Exchange-traded funds
Equity securities
Fair Value - 12 months or greater		0
Unrealized Losses - 12 months or greater		0
Fair Value - Less than 12 months		12,323
Unrealized Losses - less than 12 months		(294)
Total Fair Value		12,323
Total Unrealized Losses		(294)
Bond mutual funds
Equity securities
Fair Value - 12 months or greater		0
Unrealized Losses - 12 months or greater		0
Fair Value - Less than 12 months		12,184
Unrealized Losses - less than 12 months		(999)
Total Fair Value		12,184
Total Unrealized Losses		$ (999)

INVESTMENTS - Mortgage loans (D

INVESTMENTS - Mortgage loans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Mortgage Loans held-for-investment:
Commercial	$ 298,650,000	$ 325,062,000
Total Mortgage Loans held-for-investment	$ 298,650,000	$ 325,062,000
% of Total
Commercial	100.00%	100.00%
Total Mortgage Loans held-for-investment	100.00%	100.00%
Debt service coverage ratio, in excess of	2.2
Loan-to-value ratio, percent (less than)	60.00%
Credit losses on commercial mortgage loans	$ 0	$ 0

INVESTMENTS - Other Investments

INVESTMENTS - Other Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Investments [Line Items]
Fair value	$ 787,787	$ 1,009,373
Percentage of total fair value	100.00%	100.00%
Unfunded commitments related to other investments	$ 507,000	$ 414,000
Hedge funds | Lockup Redemption Restriction
Other Investments [Line Items]
Fair value of other investments subject to redemption restrictions	$ 27,000	$ 38,000
Percentage of fair value of other investments subject to redemption restrictions	14.00%	11.00%
Long/short equity funds
Other Investments [Line Items]
Fair value	$ 26,779	$ 38,470
Percentage of total fair value	3.00%	4.00%
Redemption notice period	60 days	60 days
Multi-strategy funds
Other Investments [Line Items]
Fair value	$ 153,883	$ 286,164
Percentage of total fair value	20.00%	28.00%
Multi-strategy funds | Other Redemption Restriction
Other Investments [Line Items]
Unfunded commitments related to other investments	$ 84,000	$ 16,000
Investment term	2 years
Multi-strategy funds | Minimum
Other Investments [Line Items]
Redemption notice period	60 days	60 days
Multi-strategy funds | Maximum
Other Investments [Line Items]
Redemption notice period	95 days	95 days
Event-driven funds
Other Investments [Line Items]
Fair value	$ 13,936	$ 39,177
Percentage of total fair value	2.00%	4.00%
Redemption notice period	45 days	45 days
Direct lending funds
Other Investments [Line Items]
Fair value	$ 274,478	$ 250,681
Percentage of total fair value	35.00%	25.00%
Direct lending funds | Other Redemption Restriction
Other Investments [Line Items]
Unfunded commitments related to other investments	$ 210,000	$ 137,000
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]
Fair value	$ 64,566	$ 68,812
Percentage of total fair value	8.00%	7.00%
Unfunded commitments related to other investments	$ 16,000	$ 21,000
Investment term	10 years
Real estate funds
Other Investments [Line Items]
Fair value	$ 84,202	$ 50,009
Percentage of total fair value	11.00%	5.00%
Real estate funds | Other Redemption Restriction
Other Investments [Line Items]
Unfunded commitments related to other investments	$ 147,000	$ 115,000
Real estate funds | Minimum | Other Redemption Restriction
Other Investments [Line Items]
Investment term	7 years
CLO-Equities
Other Investments [Line Items]
Fair value	$ 21,271	$ 31,413
Percentage of total fair value	2.00%	2.00%
Other privately held investments
Other Investments [Line Items]
Fair value	$ 44,518	$ 46,430
Percentage of total fair value	6.00%	5.00%
Overseas deposits
Other Investments [Line Items]
Fair value	$ 104,154	$ 198,217
Percentage of total fair value	13.00%	20.00%
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 inv

INVESTMENTS - Equity method investments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	$ 0	$ 1,000,000	$ 107,913,000
Equity method investments	$ 108,103,000	108,597,000
Harrington Reinsurance Holdings Limited
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments			$ 108,000,000
Equity method investment, ownership percentage			19.00%
Equity method investment, difference between carrying amount and underlying equity			$ 5,000,000
U.S. | Other Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Equity method investment, other than temporary impairment		9,000,000
Equity method investments		$ 0

INVESTMENTS - Net Investment In

INVESTMENTS - Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net Investment Income [Line Items]
Gross investment income									$ 465,806	$ 427,994	$ 383,544
Investment expenses									(27,299)	(27,189)	(30,209)
Net investment income	$ 113,128	$ 114,421	$ 109,960	$ 100,999	$ 100,908	$ 95,169	$ 106,063	$ 98,664	438,507	400,805	353,335
Fixed maturities
Net Investment Income [Line Items]
Gross investment income									356,273	312,662	305,459
Other investments
Net Investment Income [Line Items]
Gross investment income									48,959	76,858	42,514
Equity securities
Net Investment Income [Line Items]
Gross investment income									10,077	14,919	16,306
Mortgage loans
Net Investment Income [Line Items]
Gross investment income									13,566	10,780	7,996
Cash and cash equivalents
Net Investment Income [Line Items]
Gross investment income									27,566	10,057	9,209
Short-term investments
Net Investment Income [Line Items]
Gross investment income									$ 9,365	$ 2,718	$ 2,060

INVESTMENTS - Net Investment Ga

INVESTMENTS - Net Investment Gains (Losses) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Gross realized investment gains
Fixed maturities and short-term investments									$ 46,067	$ 72,046	$ 86,267
Equity securities									20,435	78,343	19,104
Gross realized investment gains									66,502	150,389	105,371
Gross realized investment losses
Fixed maturities and short-term investments									(142,153)	(98,442)	(134,460)
Equity securities									(3,389)	(959)	(16,155)
Gross realized investment losses									(145,542)	(99,401)	(150,615)
Net OTTI charge recognized in net income									(9,733)	(14,493)	(26,210)
Change in fair value of investment derivatives									5,445	(8,269)	10,929
Change in fair value of equity securities									(66,890)	0	0
Total net investment gains (losses)	$ (72,667)	$ (17,628)	$ (45,093)	$ (14,830)	$ 43,038	$ 14,632	$ (4,392)	$ (25,050)	$ (150,218)	$ 28,226	$ (60,525)

INVESTMENTS - OTTI recognized i

INVESTMENTS - OTTI recognized in earnings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]
Total OTTI recognized in net income	$ 9,733	$ 14,493	$ 26,210
Non-U.S. government
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]
Total OTTI recognized in net income	4,697	8,187	3,557
Corporate debt
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]
Total OTTI recognized in net income	4,995	6,306	20,093
Non-Agency CMBS
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]
Total OTTI recognized in net income	41	0	0
Fixed maturities
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]
Total OTTI recognized in net income	9,733	14,493	23,650
Exchange-traded funds
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]
Total OTTI recognized in net income	0	0	2,560
Equity securities
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]
Total OTTI recognized in net income	$ 0	$ 0	$ 2,560

INVESTMENTS - Credit loss table

INVESTMENTS - Credit loss table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Credit Losses For Which a Portion of OTTI Was Recognized in AOCI [Roll Forward]
Balance at beginning of period	$ 1,494	$ 1,493
Credit impairments recognized on securities not previously impaired	0	0
Additional credit impairments recognized on securities previously impaired	8	13
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	(992)	(12)
Balance at end of period	$ 510	$ 1,494

INVESTMENTS - Securities narrat

INVESTMENTS - Securities narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Schedule Of Available For Sale Securities [Line Items]
Fair value	$ 11,435,347	$ 12,622,006
Total Unrealized Losses	215,000	91,000
Gross unrealized losses	(17,882)	(1,883)
Fair value	381,633	635,511
Non-U.S. government
Schedule Of Available For Sale Securities [Line Items]
Fair value	493,016	806,299
Total Unrealized Losses	16,120	9,523
Non-U.S. government | Eurozone
Schedule Of Available For Sale Securities [Line Items]
Fair value	29,000	185,000
CMBS
Schedule Of Available For Sale Securities [Line Items]
Fair value	1,092,530	777,728
Total Unrealized Losses	$ 13,795	$ 3,125
CMBS | Weighted Average
Schedule Of Available For Sale Securities [Line Items]
Subordination percentage input for determining credit losses	31.00%	29.00%
Non-Agency RMBS
Schedule Of Available For Sale Securities [Line Items]
Fair value	$ 40,687	$ 46,831
Total Unrealized Losses	1,282	799
Non-Agency RMBS | Prime
Schedule Of Available For Sale Securities [Line Items]
Fair value	31,000	34,000
Non-Agency RMBS | Alt A
Schedule Of Available For Sale Securities [Line Items]
Fair value	$ 5,000	$ 8,000

INVESTMENTS - Restricted assets

INVESTMENTS - Restricted assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Restricted Investments [Line Items]
Collateral in Trust for inter-company agreements	$ 2,121,522	$ 3,310,180
Collateral for secured letter of credit facility	470,051	386,451
Funds at Lloyd's	1,307,945	1,192,717
Collateral in Trust for third party agreements	1,510,416	2,085,443
Collateral in Trust for third party agreements	1,510,416	2,085,443
Securities on deposit with regulatory authorities	64,360	53,925
Total restricted investments	5,474,294	7,028,716
Syndicate 2,007
Restricted Investments [Line Items]
Collateral in Trust for third party agreements	403,000	1,120,000
Collateral in Trust for third party agreements	403,000	1,120,000
Pledged cash for third party insurance and reinsurance agreements	39,000	55,000
Syndicate 1,686
Restricted Investments [Line Items]
Pledged cash for third party insurance and reinsurance agreements	$ 154,000	$ 140,000

INVESTMENTS - Reverse repurchas

INVESTMENTS - Reverse repurchase agreements (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Value of reverse repurchase agreements	$ 189	$ 37
Minimum required collateral for reverse repurchase agreements, expressed as a percentage of loan principal	102.00%

FAIR VALUE MEASUREMENTS - Fair

FAIR VALUE MEASUREMENTS - Fair value on a recurring basis (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	$ 11,435,347	$ 12,622,006
Equity securities	381,633	635,511
Other investments	787,787	1,009,373
Short-term investments	144,040	83,661
Derivative instruments	8,237	5,125
Insurance-linked securities		25,090
Total Assets	12,757,044	14,380,766
Net derivative assets	14,522	14,386
Cash settled awards	20,648	21,535
Total Liabilities	35,170	35,921
U.S. government and agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,515,697	1,712,469
Non-U.S. government
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	493,016	806,299
Corporate debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	4,876,921	5,297,866
Agency RMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,643,308	2,395,152
CMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,092,530	777,728
Non-Agency RMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	40,687	46,831
ABS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,637,603	1,436,281
Municipals
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	135,585	149,380
Common stocks
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	527	25,658
Exchange-traded funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	236,839	427,633
Bond mutual funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	144,267	182,220
Hedge funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	194,598	363,811
Direct lending funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	274,478	250,681
Private equity funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	64,566	68,812
Real estate funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	84,202	50,009
Other privately held investments
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	44,518	46,430
CLO-Equities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	21,271	31,413
Overseas deposits
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	104,154	198,217
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	1,480,466	1,658,622
Equity securities	237,366	453,291
Other investments	0	0
Short-term investments	0	0
Derivative instruments	0	0
Insurance-linked securities		0
Total Assets	1,717,832	2,111,913
Net derivative assets	0	0
Cash settled awards	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	1,480,466	1,658,622
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	527	25,658
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	236,839	427,633
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	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	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	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	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	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	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	0	0
Significant other observable inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	9,868,202	10,910,487
Equity securities	144,267	182,220
Other investments	104,154	198,217
Short-term investments	144,040	83,661
Derivative instruments	8,237	5,125
Insurance-linked securities		0
Total Assets	10,268,900	11,379,710
Net derivative assets	4,223	2,876
Cash settled awards	20,648	21,535
Total Liabilities	24,871	24,411
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	35,231	53,847
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	493,016	806,299
Significant other observable inputs (Level 2) | Corporate debt
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	4,827,909	5,244,969
Significant other observable inputs (Level 2) | Agency RMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,643,308	2,395,152
Significant other observable inputs (Level 2) | CMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,073,396	777,728
Significant other observable inputs (Level 2) | Non-Agency RMBS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	40,687	46,831
Significant other observable inputs (Level 2) | ABS
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,619,070	1,436,281
Significant other observable inputs (Level 2) | Municipals
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	135,585	149,380
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	144,267	182,220
Significant other observable inputs (Level 2) | Hedge funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	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	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	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	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	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	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	104,154	198,217
Significant unobservable inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	86,679	52,897
Equity securities	0	0
Other investments	65,789	77,843
Short-term investments	0	0
Derivative instruments	0	0
Insurance-linked securities		25,090
Total Assets	152,468	155,830
Net derivative assets	10,299	11,510
Cash settled awards	0	0
Total Liabilities	10,299	11,510
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	49,012	52,897
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	19,134	0
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	18,533	0
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	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	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	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	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	44,518	46,430
Significant unobservable inputs (Level 3) | CLO-Equities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	21,271	31,413
Significant unobservable inputs (Level 3) | Overseas deposits
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	0	0
Fair value based on NAV practical expedient
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	617,844	733,313
Total Assets	617,844	733,313
Fair value based on NAV practical expedient | Hedge funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	194,598	363,811
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	274,478	250,681
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	64,566	68,812
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	84,202	50,009
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	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	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	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Level

FAIR VALUE MEASUREMENTS - Level 3 fair value inputs (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value	$ 787,787	$ 1,009,373
Net derivative liability	(14,522)	(14,386)
Significant unobservable inputs (Level 3)
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value	65,789	77,843
Net derivative liability	(10,299)	$ (11,510)
Significant unobservable inputs (Level 3) | Other investments - CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value	$ 21,271
Estimated maturity dates (years)	7 years
Significant unobservable inputs (Level 3) | Other investments - CLO-Equities | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Estimated maturity dates (years)	7 years
Significant unobservable inputs (Level 3) | Other privately held investments
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair value	$ 44,518
Default rates | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	0.030
Default rates | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	0.030
Loss severity rate | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	0.35
Loss severity rate | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	0.35
Collateral spreads | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	0.030
Collateral spreads | Significant unobservable inputs (Level 3) | Other investments - CLO-Equities | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	0.030
Discount rate | Significant unobservable inputs (Level 3)
Fair Value Inputs Assets Quantitative Information [Line Items]
Derivative liability	0.026
Discount rate | Significant unobservable inputs (Level 3) | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Derivative liability	0.026
Discount rate | Significant unobservable inputs (Level 3) | Other privately held investments | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	0.030
Discount rate | Significant unobservable inputs (Level 3) | Other privately held investments | Maximum
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	0.080
Discount rate | Significant unobservable inputs (Level 3) | Other privately held investments | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	0.071

FAIR VALUE MEASUREMENTS - Lev_2

FAIR VALUE MEASUREMENTS - Level 3 for financial instruments measured at fair value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	$ 155,830	$ 226,797
Transfers into Level 3	10,010	2,324
Transfers out of Level 3	(4,279)	(21,670)
Included in net income	5,033	4,359
Included in OCI	5,752	(39)
Purchases	47,577	19,766
Sales	(11,555)	(22,903)
Settlements/ distributions	(55,900)	(52,804)
Closing balance	152,468	155,830
Change in unrealized investment gain/(loss) relating to assets held at the reporting date	5,714	4,209
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	11,510	6,500
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in earnings	(1,211)	9,320
Included in OCI	0	0
Purchases	0	12,472
Sales	0	0
Settlements/ distributions	0	(16,782)
Closing balance	10,299	11,510
Change in unrealized investment gain/(loss) relating to liabilities held at the reporting date	(1,211)	(962)
Fixed maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	52,897	96,400
Transfers into Level 3	10,010	2,324
Transfers out of Level 3	(4,279)	(21,670)
Included in net income	(591)	(503)
Included in OCI	5,752	(39)
Purchases	44,467	17,062
Sales	(7,446)	(22,903)
Settlements/ distributions	(14,131)	(17,774)
Closing balance	86,679	52,897
Change in unrealized investment gain/(loss) relating to assets held at the reporting date	0	0
Corporate debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	52,897	75,875
Transfers into Level 3	2,935	2,324
Transfers out of Level 3	(4,279)	(2,721)
Included in net income	(591)	(503)
Included in OCI	6,343	(1,524)
Purchases	10,267	17,062
Sales	(7,446)	(22,903)
Settlements/ distributions	(11,114)	(14,713)
Closing balance	49,012	52,897
Change in unrealized investment gain/(loss) relating to assets held at the reporting date	0	0
CMBS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	0	3,061
Transfers into Level 3	5,096	0
Transfers out of Level 3	0	0
Included in net income	0	0
Included in OCI	(145)	0
Purchases	17,200	0
Sales	0	0
Settlements/ distributions	(3,017)	(3,061)
Closing balance	19,134	0
Change in unrealized investment gain/(loss) relating to assets held at the reporting date	0	0
ABS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	0	17,464
Transfers into Level 3	1,979	0
Transfers out of Level 3	0	(18,949)
Included in net income	0	0
Included in OCI	(446)	1,485
Purchases	17,000	0
Sales	0	0
Settlements/ distributions	0	0
Closing balance	18,533	0
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	77,843	102,842
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	5,714	4,142
Included in OCI	0	0
Purchases	3,110	2,704
Sales	(4,109)	0
Settlements/ distributions	(16,769)	(31,845)
Closing balance	65,789	77,843
Change in unrealized investment gain/(loss) relating to assets held at the reporting date	5,714	4,142
Other privately held investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	46,430	42,142
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	(913)	1,584
Included in OCI	0	0
Purchases	3,110	2,704
Sales	(4,109)	0
Settlements/ distributions	0	0
Closing balance	44,518	46,430
Change in unrealized investment gain/(loss) relating to assets held at the reporting date	(913)	1,584
CLO-Equities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	31,413	60,700
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	6,627	2,558
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	(16,769)	(31,845)
Closing balance	21,271	31,413
Change in unrealized investment gain/(loss) relating to assets held at the reporting date	6,627	2,558
Other assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	25,090	27,555
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	(90)	720
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	(25,000)	(3,185)
Closing balance	0	25,090
Change in unrealized investment gain/(loss) relating to assets held at the reporting date	0	67
Derivative instruments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	0	2,532
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	0	653
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	0	(3,185)
Closing balance	0	0
Change in unrealized investment gain/(loss) relating to assets held at the reporting date	0	0
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	11,510	6,500
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in earnings	(1,211)	9,320
Included in OCI	0	0
Purchases	0	12,472
Sales	0	0
Settlements/ distributions	0	(16,782)
Closing balance	10,299	11,510
Change in unrealized investment gain/(loss) relating to liabilities held at the reporting date	(1,211)	(962)
Insurance-linked securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Opening balance	25,090	25,023
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income	(90)	67
Included in OCI	0	0
Purchases	0	0
Sales	0	0
Settlements/ distributions	(25,000)	0
Closing balance	0	25,090
Change in unrealized investment gain/(loss) relating to assets held at the reporting date	$ 0	$ 67

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details) $ in Millions	Dec. 31, 2018USD ($)hedge_fund	Dec. 31, 2017USD ($)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Number of hedge funds with reporting lag | hedge_fund	2
Percentage of funds reported on a lag	61.00%	44.00%
Reported Value Measurement
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	$ 1,342	$ 1,341
Other notes payable		36
Estimate of Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior notes	$ 1,334	1,412
Other notes payable		$ 36

DERIVATIVE INSTRUMENTS - Balan

DERIVATIVE INSTRUMENTS - Balance sheet classification of derivatives recorded at fair value (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Asset derivative fair value	$ 8,237	$ 5,125
Liability derivative fair value	14,522	14,386
Not Designated as Hedging Instruments | Other assets
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Asset derivative fair value	8,237	5,125
Not Designated as Hedging Instruments | Other liabilities
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Liability derivative fair value	14,522	14,386
Not Designated as Hedging Instruments | Investment Portfolio | Foreign exchange forward contracts
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative notional amount	79,336	137,422
Not Designated as Hedging Instruments | Investment Portfolio | Foreign exchange forward contracts | Other assets
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Asset derivative fair value	262	10
Not Designated as Hedging Instruments | Investment Portfolio | Foreign exchange forward contracts | Other liabilities
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Liability derivative fair value	531	619
Not Designated as Hedging Instruments | Investment Portfolio | Interest rate swaps
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative notional amount	150,000	191,000
Not Designated as Hedging Instruments | Investment Portfolio | Interest rate swaps | Other assets
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Asset derivative fair value	0	448
Not Designated as Hedging Instruments | Investment Portfolio | Interest rate swaps | Other liabilities
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Liability derivative fair value	1,116	1,556
Not Designated as Hedging Instruments | Underwriting Portfolio | Foreign exchange forward contracts
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative notional amount	737,419	698,959
Not Designated as Hedging Instruments | Underwriting Portfolio | Foreign exchange forward contracts | Other assets
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Asset derivative fair value	7,975	4,667
Not Designated as Hedging Instruments | Underwriting Portfolio | Foreign exchange forward contracts | Other liabilities
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Liability derivative fair value	2,576	701
Not Designated as Hedging Instruments | Underwriting Portfolio | Derivatives - Other underwriting-related derivatives
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Derivative notional amount	85,000	85,000
Not Designated as Hedging Instruments | Underwriting Portfolio | Derivatives - Other underwriting-related derivatives | Other assets
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Asset derivative fair value	0	0
Not Designated as Hedging Instruments | Underwriting Portfolio | Derivatives - Other underwriting-related derivatives | Other liabilities
Derivative Fair Values on Consolidated Balance Sheet [Line Items]
Liability derivative fair value	$ 10,299	$ 11,510

DERIVATIVE INSTRUMENTS - Offse

DERIVATIVE INSTRUMENTS - Offsetting assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative assets
Gross amounts	$ 11,967	$ 8,178
Gross amounts offset	(3,730)	(3,053)
Net Amounts	8,237	5,125
Derivative liabilities
Gross amounts	18,252	17,439
Gross amounts offset	(3,730)	(3,053)
Net Amounts	$ 14,522	$ 14,386

DERIVATIVE INSTRUMENTS - Unrea

DERIVATIVE INSTRUMENTS - Unrealized and realized gains (losses) recognized in earnings for derivatives (Details) - Not Designated as Hedging Instruments - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
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	$ 4,320	$ 8,961	$ 5,278
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	3,446	(6,935)	10,929
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	1,999	(1,334)	0
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	(3,509)	25,383	(8,179)
Underwriting Portfolio | Weather-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	0	(9,629)	4,910
Underwriting Portfolio | Commodity 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	0	0	(2,382)
Derivatives - Other underwriting-related derivatives | Commodity 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	$ 2,384	$ 1,476	$ 0

RESERVE FOR LOSSES AND LOSS E_3

RESERVE FOR LOSSES AND LOSS EXPENSES - Narrative (Details)	12 Months Ended
	Dec. 31, 2018
Minimum
Claims Development [Line Items]
Development for an accident year or underwriting year, recognition period	1 year
Maximum
Claims Development [Line Items]
Development for an accident year or underwriting year, recognition period	3 years

RESERVE FOR LOSSES AND LOSS E_4

RESERVE FOR LOSSES AND LOSS EXPENSES - Reserve for losses and loss expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Insurance Loss Reserves [Abstract]
Reserve for reported losses and loss expenses	$ 4,626,204	$ 5,137,659
Reserve for losses incurred but not reported	7,654,565	7,859,894
Reserve for losses and loss expenses	$ 12,280,769	$ 12,997,553	$ 9,697,827	$ 9,646,285

RESERVE FOR LOSSES AND LOSS E_5

RESERVE FOR LOSSES AND LOSS EXPENSES - Reserve Roll-Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Beginning and Ending Gross Unpaid Losses and Loss Expenses
Gross reserve for losses and loss expenses, beginning of year	$ 12,997,553	$ 9,697,827	$ 9,646,285
Less reinsurance recoverable on unpaid losses, beginning of year	(3,159,514)	(2,276,109)	(2,031,309)
Net reserve for unpaid losses and loss expenses, beginning of year	9,838,039	7,421,718	7,614,976
Net incurred losses and loss expenses related to:
Current year	3,389,949	3,487,826	2,496,574
Prior years	(199,662)	(200,054)	(292,377)
Net incurred losses and loss expenses	3,190,287	3,287,772	2,204,197
Net paid losses and loss expenses related to:
Current year	(724,199)	(703,796)	(428,153)
Prior years	(2,368,615)	(1,880,882)	(1,763,696)
Net paid losses and loss expenses	(3,092,814)	(2,584,678)	(2,191,849)
Foreign exchange and other	(1,156,412)	1,713,227	(205,606)
Net reserve for unpaid losses and loss expenses, end of year	8,779,100	9,838,039	7,421,718
Reinsurance recoverable on unpaid losses, end of year	3,501,669	3,159,514	2,276,109
Gross reserve for losses and loss expenses, end of year	$ 12,280,769	$ 12,997,553	$ 9,697,827

RESERVE FOR LOSSES AND LOSS E_6

RESERVE FOR LOSSES AND LOSS EXPENSES - Incurred losses narrative (Details) - USD ($) $ in Thousands	Feb. 13, 2017	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Apr. 16, 2018	Oct. 02, 2017	Apr. 01, 2017	Mar. 20, 2017	Mar. 19, 2017	Dec. 31, 2015
Additional Information Related to Net Incurred Losses [Line Items]
Net losses and loss expenses, net of reinstatement premiums											$ 3,389,949	$ 3,487,826	$ 2,496,574
Reinsurance recoverable on unpaid losses		$ 3,501,669				$ 3,159,514	$ 3,159,514				3,501,669	3,159,514	2,276,109	$ 108,000					$ 2,031,309
Reserve for losses and loss expenses		12,280,769				12,997,553	12,997,553				12,280,769	12,997,553	9,697,827						$ 9,646,285
Foreign exchange and other											1,156,412	(1,713,227)	205,606
Net favorable (adverse) prior year reserve development											199,662	200,054	292,377
Net premiums earned		$ 1,214,469	$ 1,224,075	$ 1,185,548	$ 1,167,402	1,211,495		$ 1,017,131	$ 981,431	$ 938,703	4,791,495	4,148,760	3,705,625
Retroactive Reinsurance Recoverable
Additional Information Related to Net Incurred Losses [Line Items]
Foreign exchange and other													150,000
Discontinued Operations, Disposed of by Means Other than Sale
Additional Information Related to Net Incurred Losses [Line Items]
Liability for unpaid claims and claims adjustment expense	$ (223,000)
Reduction in reinsurance recoverables on unpaid and paid loses by	$ 223,000
Aviabel
Additional Information Related to Net Incurred Losses [Line Items]
Interests acquired																100.00%
Reinsurance recoverable on unpaid and paid losses						5,000	5,000					5,000
Foreign exchange and other						79,000	79,000					79,000
Novae
Additional Information Related to Net Incurred Losses [Line Items]
Interests acquired															100.00%
Reserve for losses and loss expenses						2,126,000	2,126,000					2,126,000
Reinsurance recoverable on unpaid and paid losses						$ 788,000	788,000					788,000
Net premiums earned							$ 140,635
Catastrophe and Weather-related Events
Additional Information Related to Net Incurred Losses [Line Items]
Net losses and loss expenses, net of reinstatement premiums											430,000	835,000	204,000
Syndicate 2,007
Additional Information Related to Net Incurred Losses [Line Items]
Ceded reserves for losses and loss expenses											819,000
Reinsurance
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable (adverse) prior year reserve development											106,856	139,595	243,399
Insurance
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable (adverse) prior year reserve development											92,806	60,459	48,978
Short Tail Lines Insurance and Reinsurance Business
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable (adverse) prior year reserve development											86,000	60,000	148,000
Professional lines | Reinsurance
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable (adverse) prior year reserve development											21,000	44,000	30,000
Professional lines | Insurance
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable (adverse) prior year reserve development											32,000	26,000	14,000
Credit and surety | Reinsurance
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable (adverse) prior year reserve development											33,000	33,000	10,000
Motor Reserve Class | Reinsurance
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable (adverse) prior year reserve development											23,000	1,000	55,000
Discount rate																	(0.75%)	2.50%
Liability Insurance Business | Reinsurance
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable (adverse) prior year reserve development											23,000	43,000	44,000
Liability Insurance Business | Insurance
Additional Information Related to Net Incurred Losses [Line Items]
Net favorable (adverse) prior year reserve development											(22,000)	(8,000)	(8,000)
Operating Segments
Additional Information Related to Net Incurred Losses [Line Items]
Net premiums earned											4,791,495	4,148,760	3,705,625
Operating Segments | Reinsurance
Additional Information Related to Net Incurred Losses [Line Items]
Net premiums earned											2,428,889	2,332,322	2,171,343
Operating Segments | Insurance
Additional Information Related to Net Incurred Losses [Line Items]
Net premiums earned											2,362,606	1,816,438	1,534,282
Operating Segments | Professional lines | Reinsurance
Additional Information Related to Net Incurred Losses [Line Items]
Net premiums earned											220,687	226,622	289,868
Operating Segments | Professional lines | Insurance
Additional Information Related to Net Incurred Losses [Line Items]
Net premiums earned											570,241	519,759	510,806
Operating Segments | Accident and health | Reinsurance
Additional Information Related to Net Incurred Losses [Line Items]
Net premiums earned											299,813	289,925	243,039
Operating Segments | Accident and health | Insurance
Additional Information Related to Net Incurred Losses [Line Items]
Net premiums earned											$ 207,777	$ 199,121	$ 141,107

RESERVE FOR LOSSES AND LOSS E_7

RESERVE FOR LOSSES AND LOSS EXPENSES - Prior year development (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Net favorable prior year reserve development	$ 199,662	$ 200,054	$ 292,377
Insurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Net favorable prior year reserve development	92,806	60,459	48,978
Reinsurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Net favorable prior year reserve development	$ 106,856	$ 139,595	$ 243,399

RESERVE FOR LOSSES AND LOSS E_8

RESERVE FOR LOSSES AND LOSS EXPENSES - Incurred claims and allocated claim adjustment expenses, net of reinsurance (Details) $ in Thousands	Dec. 31, 2018USD ($)claim	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)
Insurance | Property and other
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 3,583,317
Insurance | Property and other | Accident Year 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	77,338	$ 78,395	$ 78,150	$ 78,490	$ 78,269	$ 80,461	$ 82,460	$ 89,768	$ 99,079	$ 117,309
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 83
Cumulative number of reported claims | claim	3,201
Insurance | Property and other | Accident Year 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 113,767	114,866	115,316	115,635	116,562	122,111	147,426	155,032	175,012
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 867
Cumulative number of reported claims | claim	4,422
Insurance | Property and other | Accident Year 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 279,996	281,866	281,405	282,755	285,745	306,114	338,220	359,132
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 979
Cumulative number of reported claims | claim	6,348
Insurance | Property and other | Accident Year 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 350,827	351,673	357,267	361,476	381,746	399,473	391,646
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 8,992
Cumulative number of reported claims | claim	29,931
Insurance | Property and other | Accident Year 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 276,940	266,727	267,022	271,157	297,713	308,359
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 6,687
Cumulative number of reported claims | claim	53,172
Insurance | Property and other | Accident Year 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 326,100	327,389	343,333	354,219	360,130
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 5,917
Cumulative number of reported claims | claim	62,444
Insurance | Property and other | Accident Year 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 253,729	257,927	268,897	277,332
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 5,642
Cumulative number of reported claims | claim	47,052
Insurance | Property and other | Accident Year 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 367,362	376,458	349,152
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 12,290
Cumulative number of reported claims | claim	92,867
Insurance | Property and other | Accident Year 2017
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 825,176	882,968
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 42,188
Cumulative number of reported claims | claim	663,914
Insurance | Property and other | Accident Year 2018
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 712,082
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 187,391
Cumulative number of reported claims | claim	730,832
Insurance | Marine
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 920,554
Insurance | Marine | Accident Year 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	50,735	52,283	52,400	53,514	54,906	57,106	64,477	69,862	74,181	80,615
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 359
Cumulative number of reported claims | claim	3,220
Insurance | Marine | Accident Year 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 45,125	45,543	47,249	48,650	51,483	53,388	66,389	70,394	68,528
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 643
Cumulative number of reported claims | claim	3,196
Insurance | Marine | Accident Year 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 68,829	68,140	65,983	65,769	65,766	72,530	78,700	90,717
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 1,005
Cumulative number of reported claims | claim	3,830
Insurance | Marine | Accident Year 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 72,585	74,445	71,823	70,855	68,715	82,648	89,639
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 12,055
Cumulative number of reported claims | claim	4,134
Insurance | Marine | Accident Year 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 82,136	82,547	97,265	96,210	100,767	79,610
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 2,729
Cumulative number of reported claims | claim	2,351
Insurance | Marine | Accident Year 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 45,980	44,392	48,481	44,463	59,558
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 5,454
Cumulative number of reported claims | claim	2,157
Insurance | Marine | Accident Year 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 129,627	136,827	140,050	158,755
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 8,498
Cumulative number of reported claims | claim	2,219
Insurance | Marine | Accident Year 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 76,743	78,779	86,264
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 12,819
Cumulative number of reported claims | claim	2,795
Insurance | Marine | Accident Year 2017
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 170,085	171,936
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 49,990
Cumulative number of reported claims | claim	3,863
Insurance | Marine | Accident Year 2018
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 178,709
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 113,414
Cumulative number of reported claims | claim	3,250
Insurance | Aviation
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 261,202
Insurance | Aviation | Accident Year 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	13,821	14,330	14,604	15,437	16,618	16,743	18,090	18,752	14,560	17,468
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 41
Cumulative number of reported claims | claim	1,659
Insurance | Aviation | Accident Year 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 8,900	8,548	8,744	8,699	8,769	9,749	11,422	11,699	12,922
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 78
Cumulative number of reported claims | claim	1,950
Insurance | Aviation | Accident Year 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 7,203	7,242	7,275	8,422	9,552	12,779	15,390	17,723
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 205
Cumulative number of reported claims | claim	2,145
Insurance | Aviation | Accident Year 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 7,695	7,804	7,758	8,708	10,791	10,668	12,789
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 200
Cumulative number of reported claims | claim	2,242
Insurance | Aviation | Accident Year 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 15,502	15,618	15,243	15,199	16,327	15,651
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 292
Cumulative number of reported claims | claim	2,320
Insurance | Aviation | Accident Year 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 22,183	22,104	24,339	23,028	20,432
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 425
Cumulative number of reported claims | claim	2,717
Insurance | Aviation | Accident Year 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 30,135	30,363	28,479	29,761
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 1,480
Cumulative number of reported claims | claim	3,484
Insurance | Aviation | Accident Year 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 34,513	34,328	29,154
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 2,845
Cumulative number of reported claims | claim	3,456
Insurance | Aviation | Accident Year 2017
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 63,295	56,565
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 7,676
Cumulative number of reported claims | claim	3,452
Insurance | Aviation | Accident Year 2018
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 57,955
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 12,452
Cumulative number of reported claims | claim	2,280
Insurance | Credit and political risk
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 700,799
Insurance | Credit and political risk | Accident Year 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	340,648	339,534	339,570	335,291	335,271	334,965	335,536	326,024	305,282	248,083
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 3,600
Cumulative number of reported claims | claim	24
Insurance | Credit and political risk | Accident Year 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 99,416	90,880	72,101	65,011	64,977	65,596	63,259	63,179	62,415
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 1,316
Cumulative number of reported claims | claim	6
Insurance | Credit and political risk | Accident Year 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 27,899	33,604	45,036	48,333	48,361	47,706	48,665	58,154
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 268
Cumulative number of reported claims | claim	4
Insurance | Credit and political risk | Accident Year 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 197	44	10,320	12,447	12,435	15,672	32,602
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 155
Cumulative number of reported claims | claim	4
Insurance | Credit and political risk | Accident Year 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 14,065	14,941	9,880	9,759	25,684	26,439
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 5,759
Cumulative number of reported claims | claim	1
Insurance | Credit and political risk | Accident Year 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 69,586	68,320	67,109	70,712	38,825
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 1,136
Cumulative number of reported claims | claim	6
Insurance | Credit and political risk | Accident Year 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 26,001	27,513	30,368	30,329
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 2,703
Cumulative number of reported claims | claim	2
Insurance | Credit and political risk | Accident Year 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 42,184	44,639	45,907
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 17,704
Cumulative number of reported claims | claim	1
Insurance | Credit and political risk | Accident Year 2017
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 34,631	36,563
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 28,083
Cumulative number of reported claims | claim	3
Insurance | Credit and political risk | Accident Year 2018
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 46,172
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 33,079
Cumulative number of reported claims | claim	1
Insurance | Professional lines
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 3,298,346
Insurance | Professional lines | Accident Year 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	224,778	220,524	212,994	236,751	236,657	253,979	244,466	243,978	243,522	240,092
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 13,640
Cumulative number of reported claims | claim	5,889
Insurance | Professional lines | Accident Year 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 186,340	167,038	179,517	157,921	181,917	204,744	233,407	235,610	230,353
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 18,897
Cumulative number of reported claims | claim	5,690
Insurance | Professional lines | Accident Year 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 351,747	351,247	342,598	329,318	324,739	331,800	314,466	312,805
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 33,877
Cumulative number of reported claims | claim	7,215
Insurance | Professional lines | Accident Year 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 351,498	362,606	360,596	373,306	374,315	372,782	327,590
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 50,067
Cumulative number of reported claims | claim	8,300
Insurance | Professional lines | Accident Year 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 353,112	351,330	361,785	394,461	394,548	382,270
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 70,914
Cumulative number of reported claims | claim	9,409
Insurance | Professional lines | Accident Year 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 369,129	389,610	418,164	407,688	408,103
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 111,975
Cumulative number of reported claims | claim	9,766
Insurance | Professional lines | Accident Year 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 355,300	380,265	373,747	374,209
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 127,537
Cumulative number of reported claims | claim	10,379
Insurance | Professional lines | Accident Year 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 355,601	349,223	346,289
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 152,080
Cumulative number of reported claims | claim	11,632
Insurance | Professional lines | Accident Year 2017
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 393,443	375,397
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 256,260
Cumulative number of reported claims | claim	12,903
Insurance | Professional lines | Accident Year 2018
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 357,398
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 304,926
Cumulative number of reported claims | claim	12,392
Insurance | Liability
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 1,208,108
Insurance | Liability | Accident Year 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	97,964	98,999	98,384	101,179	83,281	75,883	67,869	67,410	64,017	61,469
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 9,450
Cumulative number of reported claims | claim	4,093
Insurance | Liability | Accident Year 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 103,906	104,258	105,119	98,061	99,570	98,112	98,635	94,220	79,407
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 11,742
Cumulative number of reported claims | claim	3,670
Insurance | Liability | Accident Year 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 82,625	82,127	83,730	85,242	87,059	83,118	75,329	72,586
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 17,357
Cumulative number of reported claims | claim	3,222
Insurance | Liability | Accident Year 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 72,514	75,341	68,180	70,770	73,281	70,631	70,861
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 23,236
Cumulative number of reported claims | claim	2,837
Insurance | Liability | Accident Year 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 95,632	93,216	87,498	94,253	94,178	92,150
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 21,345
Cumulative number of reported claims | claim	3,520
Insurance | Liability | Accident Year 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 131,539	130,021	128,524	122,643	106,148
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 31,126
Cumulative number of reported claims | claim	4,614
Insurance | Liability | Accident Year 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 164,036	136,305	125,819	127,319
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 52,818
Cumulative number of reported claims | claim	5,975
Insurance | Liability | Accident Year 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 128,172	129,139	123,243
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 73,747
Cumulative number of reported claims | claim	6,628
Insurance | Liability | Accident Year 2017
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 165,061	161,211
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 107,070
Cumulative number of reported claims | claim	5,842
Insurance | Liability | Accident Year 2018
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 166,659
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 141,099
Cumulative number of reported claims | claim	3,725
Reinsurance | Property and other
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	$ 6,321,728
Reinsurance | Property and other | Accident Year 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	198,189	197,779	200,422	198,498	204,560	223,245	232,639	246,047	284,210	340,527
Total of incurred-but-not-reported liabilities plus expected development on reported claims	1,722
Reinsurance | Property and other | Accident Year 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	568,179	569,043	571,120	579,065	585,247	582,855	569,357	600,219	612,614
Total of incurred-but-not-reported liabilities plus expected development on reported claims	5,532
Reinsurance | Property and other | Accident Year 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	1,040,130	1,038,726	1,040,470	1,066,384	1,083,492	1,124,792	1,116,708	1,109,682
Total of incurred-but-not-reported liabilities plus expected development on reported claims	10,579
Reinsurance | Property and other | Accident Year 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	457,703	456,334	461,255	477,145	507,750	523,310	555,241
Total of incurred-but-not-reported liabilities plus expected development on reported claims	8,446
Reinsurance | Property and other | Accident Year 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	502,642	503,203	509,179	529,463	560,227	578,645
Total of incurred-but-not-reported liabilities plus expected development on reported claims	5,140
Reinsurance | Property and other | Accident Year 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	519,967	521,797	534,229	560,478	540,406
Total of incurred-but-not-reported liabilities plus expected development on reported claims	43,358
Reinsurance | Property and other | Accident Year 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	453,628	459,017	463,996	477,608
Total of incurred-but-not-reported liabilities plus expected development on reported claims	14,117
Reinsurance | Property and other | Accident Year 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	620,702	633,597	614,940
Total of incurred-but-not-reported liabilities plus expected development on reported claims	30,481
Reinsurance | Property and other | Accident Year 2017
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	1,080,319	1,076,458
Total of incurred-but-not-reported liabilities plus expected development on reported claims	123,562
Reinsurance | Property and other | Accident Year 2018
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	880,269
Total of incurred-but-not-reported liabilities plus expected development on reported claims	492,589
Reinsurance | Professional lines
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	1,903,167
Reinsurance | Professional lines | Accident Year 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	179,945	180,862	189,991	193,803	208,693	208,338	218,469	215,827	211,191	211,420
Total of incurred-but-not-reported liabilities plus expected development on reported claims	4,495
Reinsurance | Professional lines | Accident Year 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	165,864	179,604	189,263	196,770	214,161	214,439	211,409	210,238	210,016
Total of incurred-but-not-reported liabilities plus expected development on reported claims	10,034
Reinsurance | Professional lines | Accident Year 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	177,163	200,168	207,946	208,828	211,459	202,815	201,735	201,457
Total of incurred-but-not-reported liabilities plus expected development on reported claims	22,132
Reinsurance | Professional lines | Accident Year 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	213,850	212,485	222,499	223,813	221,808	216,415	209,889
Total of incurred-but-not-reported liabilities plus expected development on reported claims	33,873
Reinsurance | Professional lines | Accident Year 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	205,586	213,142	213,765	215,544	214,624	209,538
Total of incurred-but-not-reported liabilities plus expected development on reported claims	67,043
Reinsurance | Professional lines | Accident Year 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	233,427	219,109	219,286	219,332	219,378
Total of incurred-but-not-reported liabilities plus expected development on reported claims	48,605
Reinsurance | Professional lines | Accident Year 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	225,003	214,310	212,150	212,030
Total of incurred-but-not-reported liabilities plus expected development on reported claims	84,299
Reinsurance | Professional lines | Accident Year 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	199,879	196,246	195,061
Total of incurred-but-not-reported liabilities plus expected development on reported claims	84,621
Reinsurance | Professional lines | Accident Year 2017
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	155,892	155,211
Total of incurred-but-not-reported liabilities plus expected development on reported claims	109,070
Reinsurance | Professional lines | Accident Year 2018
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	146,558
Total of incurred-but-not-reported liabilities plus expected development on reported claims	142,282
Reinsurance | Credit and surety
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	1,201,632
Reinsurance | Credit and surety | Accident Year 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	92,519	93,688	95,321	95,726	98,958	104,236	105,062	105,827	122,111	143,398
Total of incurred-but-not-reported liabilities plus expected development on reported claims	1,304
Reinsurance | Credit and surety | Accident Year 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	74,430	75,716	77,732	79,047	86,528	90,657	93,548	100,047	119,152
Total of incurred-but-not-reported liabilities plus expected development on reported claims	4,092
Reinsurance | Credit and surety | Accident Year 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	100,146	100,718	102,529	111,019	112,964	105,955	107,811	121,471
Total of incurred-but-not-reported liabilities plus expected development on reported claims	5,770
Reinsurance | Credit and surety | Accident Year 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	128,323	131,963	140,000	148,363	151,141	148,566	160,109
Total of incurred-but-not-reported liabilities plus expected development on reported claims	8,830
Reinsurance | Credit and surety | Accident Year 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	125,112	136,402	140,589	144,472	153,616	165,413
Total of incurred-but-not-reported liabilities plus expected development on reported claims	8,083
Reinsurance | Credit and surety | Accident Year 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	128,404	139,857	143,515	136,346	135,732
Total of incurred-but-not-reported liabilities plus expected development on reported claims	11,280
Reinsurance | Credit and surety | Accident Year 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	157,612	161,789	166,951	160,837
Total of incurred-but-not-reported liabilities plus expected development on reported claims	26,891
Reinsurance | Credit and surety | Accident Year 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	149,054	141,780	142,245
Total of incurred-but-not-reported liabilities plus expected development on reported claims	38,746
Reinsurance | Credit and surety | Accident Year 2017
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	134,063	135,750
Total of incurred-but-not-reported liabilities plus expected development on reported claims	38,299
Reinsurance | Credit and surety | Accident Year 2018
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	111,969
Total of incurred-but-not-reported liabilities plus expected development on reported claims	53,762
Reinsurance | Motor
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	1,942,568
Reinsurance | Motor | Accident Year 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	77,829	80,204	77,943	83,517	92,158	90,860	89,057	87,140	79,515	81,369
Total of incurred-but-not-reported liabilities plus expected development on reported claims	17,628
Reinsurance | Motor | Accident Year 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	78,575	81,228	84,535	93,919	99,061	104,993	106,092	105,669	98,704
Total of incurred-but-not-reported liabilities plus expected development on reported claims	19,993
Reinsurance | Motor | Accident Year 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	140,191	145,482	155,948	164,559	168,436	162,586	158,750	156,069
Total of incurred-but-not-reported liabilities plus expected development on reported claims	24,417
Reinsurance | Motor | Accident Year 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	131,690	134,768	144,164	149,100	156,460	167,788	178,052
Total of incurred-but-not-reported liabilities plus expected development on reported claims	22,562
Reinsurance | Motor | Accident Year 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	131,081	134,200	137,695	147,139	158,632	162,681
Total of incurred-but-not-reported liabilities plus expected development on reported claims	21,880
Reinsurance | Motor | Accident Year 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	169,776	174,457	177,575	182,555	182,625
Total of incurred-but-not-reported liabilities plus expected development on reported claims	9,307
Reinsurance | Motor | Accident Year 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	221,982	220,527	216,808	222,768
Total of incurred-but-not-reported liabilities plus expected development on reported claims	29,755
Reinsurance | Motor | Accident Year 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	263,168	261,369	245,899
Total of incurred-but-not-reported liabilities plus expected development on reported claims	43,569
Reinsurance | Motor | Accident Year 2017
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	371,089	363,651
Total of incurred-but-not-reported liabilities plus expected development on reported claims	84,007
Reinsurance | Motor | Accident Year 2018
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	357,187
Total of incurred-but-not-reported liabilities plus expected development on reported claims	172,384
Reinsurance | Liability
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	2,070,199
Reinsurance | Liability | Accident Year 2009
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	175,770	168,917	178,260	192,287	204,531	184,811	178,149	180,945	174,121	$ 172,680
Total of incurred-but-not-reported liabilities plus expected development on reported claims	13,563
Reinsurance | Liability | Accident Year 2010
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	159,156	165,990	181,938	190,959	201,329	183,056	182,515	170,784	$ 171,634
Total of incurred-but-not-reported liabilities plus expected development on reported claims	14,137
Reinsurance | Liability | Accident Year 2011
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	191,962	193,830	194,715	197,871	191,761	174,124	172,399	$ 172,431
Total of incurred-but-not-reported liabilities plus expected development on reported claims	24,450
Reinsurance | Liability | Accident Year 2012
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	164,357	171,121	173,645	172,491	167,887	163,625	$ 167,290
Total of incurred-but-not-reported liabilities plus expected development on reported claims	27,789
Reinsurance | Liability | Accident Year 2013
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	177,273	184,147	184,467	182,428	176,465	$ 172,784
Total of incurred-but-not-reported liabilities plus expected development on reported claims	53,822
Reinsurance | Liability | Accident Year 2014
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	199,583	200,819	204,871	203,136	$ 200,203
Total of incurred-but-not-reported liabilities plus expected development on reported claims	75,626
Reinsurance | Liability | Accident Year 2015
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	215,997	216,201	215,273	$ 214,942
Total of incurred-but-not-reported liabilities plus expected development on reported claims	97,353
Reinsurance | Liability | Accident Year 2016
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	251,087	246,024	$ 240,411
Total of incurred-but-not-reported liabilities plus expected development on reported claims	131,475
Reinsurance | Liability | Accident Year 2017
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	270,564	$ 277,034
Total of incurred-but-not-reported liabilities plus expected development on reported claims	176,854
Reinsurance | Liability | Accident Year 2018
Claims Development [Line Items]
Incurred claims and allocated claim adjustment expenses, net of reinsurance	264,450
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 209,612

RESERVE FOR LOSSES AND LOSS E_9

RESERVE FOR LOSSES AND LOSS EXPENSES - Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Claims Development [Line Items]
Liabilities for claims and claim adjustment expenses, net of reinsurance	$ 8,676,295
Insurance
Claims Development [Line Items]
Liabilities for claims and claim adjustment expenses, net of reinsurance	3,540,908
Insurance | Property and other
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	2,817,520
All outstanding liabilities before 2009, net of reinsurance	5,862
Liabilities for claims and claim adjustment expenses, net of reinsurance	771,659
Insurance | Property and other | Accident Year 2009
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	77,252	$ 77,248	$ 76,980	$ 76,673	$ 74,453	$ 73,387	$ 72,499	$ 68,653	$ 60,085	$ 31,360
Insurance | Property and other | Accident Year 2010
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	110,171	109,837	109,794	110,008	109,933	105,719	94,912	86,886	48,575
Insurance | Property and other | Accident Year 2011
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	270,946	270,666	269,994	270,309	271,451	249,162	192,892	84,811
Insurance | Property and other | Accident Year 2012
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	312,894	312,818	307,639	300,129	277,230	213,138	77,088
Insurance | Property and other | Accident Year 2013
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	261,266	258,435	247,393	236,405	197,898	75,214
Insurance | Property and other | Accident Year 2014
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	315,797	311,730	304,609	258,098	131,991
Insurance | Property and other | Accident Year 2015
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	239,989	225,593	201,166	98,366
Insurance | Property and other | Accident Year 2016
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	327,706	287,049	122,407
Insurance | Property and other | Accident Year 2017
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	625,027	251,358
Insurance | Property and other | Accident Year 2018
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	276,472
Insurance | Marine
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	588,505
All outstanding liabilities before 2009, net of reinsurance	8,619
Liabilities for claims and claim adjustment expenses, net of reinsurance	340,668
Insurance | Marine | Accident Year 2009
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	50,244	48,920	48,587	48,321	45,775	45,159	43,147	39,674	30,297	17,394
Insurance | Marine | Accident Year 2010
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	43,433	43,346	46,940	45,976	45,194	42,364	33,298	28,631	18,029
Insurance | Marine | Accident Year 2011
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	66,913	64,868	60,572	59,862	58,025	54,930	44,218	26,435
Insurance | Marine | Accident Year 2012
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	54,721	52,724	50,331	49,523	44,800	38,545	10,711
Insurance | Marine | Accident Year 2013
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	76,856	65,822	63,128	54,898	44,087	18,982
Insurance | Marine | Accident Year 2014
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	35,987	26,924	26,838	15,172	6,349
Insurance | Marine | Accident Year 2015
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	111,027	108,152	54,869	21,426
Insurance | Marine | Accident Year 2016
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	57,745	31,981	12,486
Insurance | Marine | Accident Year 2017
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	68,563	14,472
Insurance | Marine | Accident Year 2018
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	23,016
Insurance | Aviation
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	178,160
All outstanding liabilities before 2009, net of reinsurance	8,362
Liabilities for claims and claim adjustment expenses, net of reinsurance	91,404
Insurance | Aviation | Accident Year 2009
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	13,616	13,665	13,700	14,203	14,266	13,902	12,780	7,026	3,583	2,081
Insurance | Aviation | Accident Year 2010
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	8,423	8,221	8,113	7,670	7,551	6,886	6,312	4,131	1,037
Insurance | Aviation | Accident Year 2011
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	6,188	6,042	5,811	5,562	5,028	4,512	2,822	638
Insurance | Aviation | Accident Year 2012
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	7,263	7,146	6,822	5,941	4,147	2,858	953
Insurance | Aviation | Accident Year 2013
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	14,200	13,594	11,444	9,746	7,326	4,399
Insurance | Aviation | Accident Year 2014
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	14,824	14,167	11,687	8,019	3,987
Insurance | Aviation | Accident Year 2015
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	23,797	21,507	16,155	8,084
Insurance | Aviation | Accident Year 2016
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	27,120	20,113	10,407
Insurance | Aviation | Accident Year 2017
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	41,671	22,512
Insurance | Aviation | Accident Year 2018
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	21,058
Insurance | Credit and political risk
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	600,313
All outstanding liabilities before 2009, net of reinsurance	(1,475)
Liabilities for claims and claim adjustment expenses, net of reinsurance	99,011
Insurance | Credit and political risk | Accident Year 2009
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	340,785	341,231	345,567	345,520	345,521	341,577	346,221	346,254	344,652	92,842
Insurance | Credit and political risk | Accident Year 2010
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	102,514	102,196	102,154	101,948	101,786	106,767	90,729	85,418	50,000
Insurance | Credit and political risk | Accident Year 2011
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	27,631	27,631	27,636	27,636	27,636	27,636	37,205	32,788
Insurance | Credit and political risk | Accident Year 2012
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	42	39	38	0	0	0	0
Insurance | Credit and political risk | Accident Year 2013
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	13,826	11,768	5,216	3,726	2,235	745
Insurance | Credit and political risk | Accident Year 2014
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	57,855	57,855	61,108	39,952	1,924
Insurance | Credit and political risk | Accident Year 2015
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	23,298	23,298	23,309	0
Insurance | Credit and political risk | Accident Year 2016
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	24,479	24,445	0
Insurance | Credit and political risk | Accident Year 2017
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	5,589	1,504
Insurance | Credit and political risk | Accident Year 2018
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	4,294
Insurance | Professional lines
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	1,756,498
All outstanding liabilities before 2009, net of reinsurance	45,848
Liabilities for claims and claim adjustment expenses, net of reinsurance	1,587,696
Insurance | Professional lines | Accident Year 2009
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	184,577	177,492	165,088	126,542	106,985	96,631	68,690	44,065	20,619	1,657
Insurance | Professional lines | Accident Year 2010
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	136,252	114,710	109,668	99,082	88,585	72,554	53,458	27,815	7,850
Insurance | Professional lines | Accident Year 2011
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	294,043	282,907	237,804	165,206	107,980	73,940	32,812	7,399
Insurance | Professional lines | Accident Year 2012
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	272,298	252,937	229,932	183,295	99,486	41,021	7,801
Insurance | Professional lines | Accident Year 2013
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	241,074	211,931	174,759	128,858	72,784	17,633
Insurance | Professional lines | Accident Year 2014
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	222,692	191,437	129,160	70,266	23,450
Insurance | Professional lines | Accident Year 2015
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	168,627	137,145	67,313	19,976
Insurance | Professional lines | Accident Year 2016
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	146,342	70,947	15,846
Insurance | Professional lines | Accident Year 2017
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	71,495	20,812
Insurance | Professional lines | Accident Year 2018
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	19,098
Insurance | Liability
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	601,478
All outstanding liabilities before 2009, net of reinsurance	43,840
Liabilities for claims and claim adjustment expenses, net of reinsurance	650,470
Insurance | Liability | Accident Year 2009
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	86,231	84,975	83,991	44,105	41,322	31,865	26,754	13,305	4,646	726
Insurance | Liability | Accident Year 2010
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	87,981	86,433	71,788	66,114	61,029	53,581	30,788	15,966	1,030
Insurance | Liability | Accident Year 2011
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	62,152	60,263	54,996	46,074	38,376	20,190	10,540	2,761
Insurance | Liability | Accident Year 2012
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	46,545	42,745	37,139	30,145	15,411	5,514	1,630
Insurance | Liability | Accident Year 2013
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	66,976	60,017	42,051	33,320	23,281	2,360
Insurance | Liability | Accident Year 2014
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	84,397	71,617	49,840	18,645	1,415
Insurance | Liability | Accident Year 2015
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	92,557	39,557	22,308	5,438
Insurance | Liability | Accident Year 2016
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	36,406	23,286	6,318
Insurance | Liability | Accident Year 2017
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	29,529	5,404
Insurance | Liability | Accident Year 2018
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	8,704
Reinsurance
Claims Development [Line Items]
Liabilities for claims and claim adjustment expenses, net of reinsurance	5,135,387
Reinsurance | Property and other
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	4,939,078
All outstanding liabilities before 2009, net of reinsurance	11,126
Liabilities for claims and claim adjustment expenses, net of reinsurance	1,393,776
Reinsurance | Property and other | Accident Year 2009
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	190,174	191,900	192,728	191,046	188,240	188,919	178,388	160,284	129,397	56,420
Reinsurance | Property and other | Accident Year 2010
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	542,909	540,616	534,893	510,061	481,009	435,155	403,566	310,268	116,143
Reinsurance | Property and other | Accident Year 2011
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	1,013,191	1,010,611	995,795	922,456	893,041	793,972	587,390	251,538
Reinsurance | Property and other | Accident Year 2012
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	415,831	413,789	404,019	389,461	367,055	294,436	122,688
Reinsurance | Property and other | Accident Year 2013
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	482,114	480,712	470,990	440,804	324,443	107,085
Reinsurance | Property and other | Accident Year 2014
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	458,032	451,890	434,354	352,361	101,937
Reinsurance | Property and other | Accident Year 2015
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	400,615	368,360	265,569	71,244
Reinsurance | Property and other | Accident Year 2016
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	519,223	375,374	126,404
Reinsurance | Property and other | Accident Year 2017
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	722,835	252,008
Reinsurance | Property and other | Accident Year 2018
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	194,154
Reinsurance | Credit and surety
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	889,415
All outstanding liabilities before 2009, net of reinsurance	13,274
Liabilities for claims and claim adjustment expenses, net of reinsurance	325,491
Reinsurance | Credit and surety | Accident Year 2009
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	87,238	87,594	87,089	87,180	87,047	84,401	80,574	78,378	76,440	32,479
Reinsurance | Credit and surety | Accident Year 2010
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	66,023	65,724	64,710	63,279	62,144	60,452	59,776	48,715	28,218
Reinsurance | Credit and surety | Accident Year 2011
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	89,004	87,571	85,242	83,036	78,477	70,850	54,012	22,449
Reinsurance | Credit and surety | Accident Year 2012
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	112,118	110,844	109,073	105,551	99,705	85,701	49,631
Reinsurance | Credit and surety | Accident Year 2013
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	108,062	106,202	98,517	91,902	77,059	32,447
Reinsurance | Credit and surety | Accident Year 2014
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	103,272	95,675	86,539	61,440	35,570
Reinsurance | Credit and surety | Accident Year 2015
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	117,594	100,464	82,174	32,935
Reinsurance | Credit and surety | Accident Year 2016
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	92,788	73,603	42,069
Reinsurance | Credit and surety | Accident Year 2017
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	74,341	37,311
Reinsurance | Credit and surety | Accident Year 2018
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	38,975
Reinsurance | Professional lines
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	911,479
All outstanding liabilities before 2009, net of reinsurance	47,397
Liabilities for claims and claim adjustment expenses, net of reinsurance	1,039,085
Reinsurance | Professional lines | Accident Year 2009
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	150,811	143,732	138,247	128,071	108,373	83,703	63,066	32,306	8,588	914
Reinsurance | Professional lines | Accident Year 2010
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	137,917	130,487	123,889	107,270	76,763	52,129	31,245	12,029	1,758
Reinsurance | Professional lines | Accident Year 2011
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	129,920	119,643	102,938	84,776	57,182	30,273	11,825	1,510
Reinsurance | Professional lines | Accident Year 2012
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	131,770	107,173	85,921	53,587	29,616	10,400	779
Reinsurance | Professional lines | Accident Year 2013
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	104,883	81,641	64,966	30,495	12,070	1,062
Reinsurance | Professional lines | Accident Year 2014
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	109,129	74,542	48,814	13,066	2,019
Reinsurance | Professional lines | Accident Year 2015
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	79,270	41,524	13,505	3,134
Reinsurance | Professional lines | Accident Year 2016
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	52,588	20,516	1,772
Reinsurance | Professional lines | Accident Year 2017
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	14,918	2,814
Reinsurance | Professional lines | Accident Year 2018
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	273
Reinsurance | Motor
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	916,565
All outstanding liabilities before 2009, net of reinsurance	146,464
Liabilities for claims and claim adjustment expenses, net of reinsurance	1,172,467
Reinsurance | Motor | Accident Year 2009
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	31,650	29,144	25,910	21,368	19,066	12,933	9,523	8,012	6,830	2,709
Reinsurance | Motor | Accident Year 2010
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	33,083	32,015	30,977	27,766	23,554	20,387	17,066	11,951	7,075
Reinsurance | Motor | Accident Year 2011
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	89,619	88,630	84,067	78,202	71,664	61,309	46,979	23,788
Reinsurance | Motor | Accident Year 2012
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	89,492	87,244	83,232	76,875	67,254	52,736	29,162
Reinsurance | Motor | Accident Year 2013
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	86,832	81,388	75,865	66,119	52,639	33,807
Reinsurance | Motor | Accident Year 2014
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	110,562	100,607	92,721	73,572	43,325
Reinsurance | Motor | Accident Year 2015
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	129,661	112,584	92,778	57,809
Reinsurance | Motor | Accident Year 2016
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	127,970	104,342	60,829
Reinsurance | Motor | Accident Year 2017
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	133,842	72,226
Reinsurance | Motor | Accident Year 2018
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	83,854
Reinsurance | Liability
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	919,946
All outstanding liabilities before 2009, net of reinsurance	54,315
Liabilities for claims and claim adjustment expenses, net of reinsurance	1,204,568
Reinsurance | Liability | Accident Year 2009
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	136,539	132,996	127,009	122,704	103,662	73,229	56,623	44,473	17,102	$ 1,704
Reinsurance | Liability | Accident Year 2010
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	128,399	119,693	108,770	97,457	83,826	62,291	46,201	17,654	$ 2,481
Reinsurance | Liability | Accident Year 2011
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	135,625	123,387	112,328	92,466	70,102	39,981	21,273	$ 5,189
Reinsurance | Liability | Accident Year 2012
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	115,571	101,115	78,190	58,735	28,388	12,798	$ 3,541
Reinsurance | Liability | Accident Year 2013
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	102,588	88,264	69,052	52,327	22,236	$ 5,969
Reinsurance | Liability | Accident Year 2014
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	89,436	70,143	48,415	28,663	$ 7,083
Reinsurance | Liability | Accident Year 2015
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	80,865	54,524	27,457	$ 7,271
Reinsurance | Liability | Accident Year 2016
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	69,526	37,688	$ 11,861
Reinsurance | Liability | Accident Year 2017
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	42,092	$ 12,424
Reinsurance | Liability | Accident Year 2018
Claims Development [Line Items]
Cumulative paid claims and allocated claim adjustment expenses, net of reinsurance	$ 19,305

RESERVE FOR LOSSES AND LOSS _10

RESERVE FOR LOSSES AND LOSS EXPENSES - Average annual percentage payout of incurred claims by age, net of reinsurance (Details)	Dec. 31, 2018
Insurance | Property and other
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	34.50%
Year 2	40.20%
Year 3	13.20%
Year 4	5.80%
Year 5	2.00%
Year 6	0.80%
Year 7	0.70%
Year 8	0.20%
Year 9	0.30%
Year 10	0.00%
Insurance | Marine
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	21.90%
Year 2	27.30%
Year 3	20.80%
Year 4	7.20%
Year 5	6.20%
Year 6	4.10%
Year 7	4.00%
Year 8	(1.50%)
Year 9	0.50%
Year 10	2.60%
Insurance | Aviation
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	22.30%
Year 2	24.80%
Year 3	20.00%
Year 4	15.50%
Year 5	8.60%
Year 6	3.10%
Year 7	2.30%
Year 8	(0.10%)
Year 9	1.00%
Year 10	(0.40%)
Insurance | Credit and political risk
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	21.70%
Year 2	38.90%
Year 3	1.60%
Year 4	3.10%
Year 5	9.90%
Year 6	3.30%
Year 7	0.40%
Year 8	0.00%
Year 9	(0.50%)
Year 10	(0.10%)
Insurance | Professional lines
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	4.10%
Year 2	11.80%
Year 3	15.70%
Year 4	13.40%
Year 5	11.60%
Year 6	9.10%
Year 7	8.20%
Year 8	7.70%
Year 9	8.60%
Year 10	3.20%
Insurance | Liability
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	2.80%
Year 2	11.80%
Year 3	12.90%
Year 4	19.40%
Year 5	10.00%
Year 6	8.10%
Year 7	5.00%
Year 8	19.00%
Year 9	1.30%
Year 10	1.30%
Reinsurance | Property and other
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	22.20%
Year 2	39.90%
Year 3	19.10%
Year 4	6.50%
Year 5	3.80%
Year 6	2.90%
Year 7	1.90%
Year 8	0.70%
Year 9	0.00%
Year 10	(0.90%)
Reinsurance | Credit and surety
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	29.90%
Year 2	30.00%
Year 3	12.60%
Year 4	5.50%
Year 5	4.30%
Year 6	1.90%
Year 7	1.30%
Year 8	0.90%
Year 9	0.50%
Year 10	(0.40%)
Reinsurance | Professional lines
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	0.90%
Year 2	5.90%
Year 3	12.10%
Year 4	14.40%
Year 5	13.30%
Year 6	12.70%
Year 7	10.50%
Year 8	5.20%
Year 9	3.80%
Year 10	3.90%
Reinsurance | Motor
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	19.50%
Year 2	14.10%
Year 3	8.60%
Year 4	5.80%
Year 5	4.70%
Year 6	4.90%
Year 7	3.00%
Year 8	2.60%
Year 9	2.80%
Year 10	3.20%
Reinsurance | Liability
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Year 1	3.40%
Year 2	9.20%
Year 3	13.10%
Year 4	12.00%
Year 5	11.20%
Year 6	11.60%
Year 7	8.10%
Year 8	5.20%
Year 9	4.50%
Year 10	2.00%

RESERVE FOR LOSSES AND LOSS _11

RESERVE FOR LOSSES AND LOSS EXPENSES - Reconciliation of development tables to consolidated balance sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Claims Development [Line Items]
Net outstanding liabilities	$ 8,676,295
Reinsurance recoverable on unpaid claims	3,501,669
Gross outstanding liabilities	12,177,964
Unallocated claims adjustment expenses	145,768
Foreign exchange and other	53,695
(Ceded)/assumed reserves related to retroactive transactions	(96,658)
Reserve for losses and loss expenses	12,280,769	$ 12,997,553	$ 9,697,827	$ 9,646,285
Insurance
Claims Development [Line Items]
Net outstanding liabilities	3,540,908
Reinsurance recoverable on unpaid claims	2,692,252
Gross outstanding liabilities	6,233,160
Insurance | Property and other
Claims Development [Line Items]
Net outstanding liabilities	771,659
Reinsurance recoverable on unpaid claims	482,207
Gross outstanding liabilities	1,253,866
Insurance | Marine
Claims Development [Line Items]
Net outstanding liabilities	340,668
Reinsurance recoverable on unpaid claims	187,164
Gross outstanding liabilities	527,832
Insurance | Aviation
Claims Development [Line Items]
Net outstanding liabilities	91,404
Reinsurance recoverable on unpaid claims	14,310
Gross outstanding liabilities	105,714
Insurance | Credit and political risk
Claims Development [Line Items]
Net outstanding liabilities	99,011
Reinsurance recoverable on unpaid claims	24,536
Gross outstanding liabilities	123,547
Insurance | Professional lines
Claims Development [Line Items]
Net outstanding liabilities	1,587,696
Reinsurance recoverable on unpaid claims	1,005,316
Gross outstanding liabilities	2,593,012
Insurance | Liability
Claims Development [Line Items]
Net outstanding liabilities	650,470
Reinsurance recoverable on unpaid claims	978,719
Gross outstanding liabilities	1,629,189
Reinsurance
Claims Development [Line Items]
Net outstanding liabilities	5,135,387
Reinsurance recoverable on unpaid claims	809,417
Gross outstanding liabilities	5,944,804
Reinsurance | Property and other
Claims Development [Line Items]
Net outstanding liabilities	1,393,776
Reinsurance recoverable on unpaid claims	435,671
Gross outstanding liabilities	1,829,447
Reinsurance | Credit and surety
Claims Development [Line Items]
Net outstanding liabilities	325,491
Reinsurance recoverable on unpaid claims	36,180
Gross outstanding liabilities	361,671
Reinsurance | Professional lines
Claims Development [Line Items]
Net outstanding liabilities	1,039,085
Reinsurance recoverable on unpaid claims	81,608
Gross outstanding liabilities	1,120,693
Reinsurance | Motor
Claims Development [Line Items]
Net outstanding liabilities	1,172,467
Reinsurance recoverable on unpaid claims	128,575
Gross outstanding liabilities	1,301,042
Reinsurance | Liability
Claims Development [Line Items]
Net outstanding liabilities	1,204,568
Reinsurance recoverable on unpaid claims	127,383
Gross outstanding liabilities	$ 1,331,951

REINSURANCE (Details)

REINSURANCE (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Premiums written
Gross									$ 6,910,065	$ 5,556,273	$ 4,970,208
Ceded									(2,251,103)	(1,529,130)	(1,217,234)
Net									4,658,962	4,027,143	3,752,974
Premiums earned
Gross									6,882,217	5,616,234	4,762,394
Ceded									(2,090,722)	(1,467,474)	(1,056,769)
Net	$ 1,214,469	$ 1,224,075	$ 1,185,548	$ 1,167,402	$ 1,211,495	$ 1,017,131	$ 981,431	$ 938,703	4,791,495	4,148,760	3,705,625
Reinsurance receivables:
Ceded losses and loss expenses									(1,565,000)	(1,010,000)	(556,000)
Provision for unrecoverable reinsurance	$ 21,000				$ 17,000				$ 21,000	$ 17,000	$ 20,000

DEBT AND FINANCING ARRANGEMEN_3

DEBT AND FINANCING ARRANGEMENTS - Senior and Notes payable, Dekania Notes (Details) - USD ($)	Dec. 06, 2017	Mar. 13, 2014	Mar. 23, 2010	Sep. 29, 2004	Jun. 30, 2004	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Senior notes [Line Items]
Net proceeds from issuance of debt						$ 0	$ 346,362,000	$ 0
Senior Notes
Senior notes [Line Items]
Interest Expense						64,000,000	51,000,000	$ 50,000,000
Senior Notes | 2010 AXIS Specialty Finance LLC Senior Notes
Senior notes [Line Items]
Face amount						$ 500,000,000
Interest rate						5.875%
Issue price (percentage of face amount)			99.624%
Net proceeds from issuance of debt			$ 495,000,000
Senior Notes | Senior Notes Due 2019 Axis Specialty Finance PLC 2014
Senior notes [Line Items]
Face amount						$ 250,000,000
Interest rate						2.65%
Issue price (percentage of face amount)		99.896%
Net proceeds from issuance of debt		$ 248,000,000
Senior Notes | Senior Notes Due 2045 Axis Specialty Finance PLC 2014
Senior notes [Line Items]
Face amount						$ 250,000,000
Interest rate						5.15%
Issue price (percentage of face amount)		99.474%
Net proceeds from issuance of debt		$ 246,000,000
Senior Notes | Senior Notes Axis Specialty Finance PLC 2017
Senior notes [Line Items]
Face amount						$ 350,000,000
Interest rate						4.00%
Issue price (percentage of face amount)	99.78%
Net proceeds from issuance of debt	$ 347,000,000
Subordinated Debt
Senior notes [Line Items]
Net proceeds from issuance of debt					$ 35,000,000
Interest Expense						$ 2,000,000	$ 2,000,000
Subordinated Debt | Dekania Notes, 15 Million
Senior notes [Line Items]
Face amount					15,000,000
Subordinated Debt | Dekania Notes, 11 Million
Senior notes [Line Items]
Face amount					$ 11,000,000
Subordinated Debt | Dekania Notes, 10 Million
Senior notes [Line Items]
Face amount				$ 10,000,000
AXIS Specialty Finance LLC
Senior notes [Line Items]
Percentage ownership in subsidiary						100.00%
AXIS Specialty Finance PLC
Senior notes [Line Items]
Percentage ownership in subsidiary	100.00%
London Interbank Offered Rate (LIBOR) | Subordinated Debt | Dekania Notes, 15 Million
Senior notes [Line Items]
Basis spread on variable rate					3.50%
London Interbank Offered Rate (LIBOR) | Subordinated Debt | Dekania Notes, 11 Million
Senior notes [Line Items]
Basis spread on variable rate					4.05%
London Interbank Offered Rate (LIBOR) | Subordinated Debt | Dekania Notes, 10 Million
Senior notes [Line Items]
Basis spread on variable rate				3.50%

DEBT AND FINANCING ARRANGEMEN_4

DEBT AND FINANCING ARRANGEMENTS - Debt maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Scheduled debt maturity
2,019	$ 250,000
2,020	500,000
2,021	0
2,022	0
2,023	0
After 2,023	600,000
Unamortized discount and debt issuance expenses	(8,039)
Total senior notes and notes payable	$ 1,341,961	$ 1,376,529

DEBT AND FINANCING ARRANGEMEN_5

DEBT AND FINANCING ARRANGEMENTS - Credit facilities (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2018	Mar. 28, 2018	Mar. 27, 2017	Mar. 26, 2017	Aug. 02, 2016	Mar. 31, 2015	Mar. 30, 2015
Letter of Credit Facility | Citibank
Line of Credit Facility [Line Items]
Maximum capacity				$ 750,000,000				$ 500,000,000	$ 750,000,000
LOC Facility term	4 years
Letters of credit outstanding			$ 395,000,000
Revolving Credit Facility | Syndication Of Lenders
Line of Credit Facility [Line Items]
Potential increase in maximum capacity			$ 150,000,000
Credit Agreement | Letter of Credit Facility
Line of Credit Facility [Line Items]
Maximum capacity						$ 250,000,000
$500 million secured LOC | Letter of Credit Facility | Citibank
Line of Credit Facility [Line Items]
Maximum capacity				$ 500,000,000	$ 500,000,000
$250 million secured LOC | Letter of Credit Facility | Citibank
Line of Credit Facility [Line Items]
Maximum capacity					$ 250,000,000
Novae Syndicated Bank Facility
Line of Credit Facility [Line Items]
Interest Expense		$ 1,000,000
Novae Syndicated Bank Facility | Letter Of Credit And Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum capacity							$ 229,000,000
Term Loan | Novae Syndicated Bank Facility
Line of Credit Facility [Line Items]
Face amount							$ 67,000,000

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES - Cash and investments (Details)	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Fixed maturity portfolio - corporate issuer concentration limit above A-	2.00%
Fixed maturity portfolio - corporate issuer concentration limit below A-	1.00%

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Reinsurance and premiums (Details)	12 Months Ended
	Dec. 31, 2018USD ($)broker	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Concentration Risk [Line Items]
Premiums receivable allowance for doubtful accounts	$ 4,000,000	$ 6,000,000
Premiums receivable, bad debt expense charges	$ 0	$ 0	$ 1,000,000
Reinsurance Recoverable On Unpaid And Paid Losses | Reinsurer Concentration | Reinsurer 1
Concentration Risk [Line Items]
Concentration risk, percentage of total	13.00%	12.00%
Reinsurance Recoverable On Unpaid And Paid Losses | Reinsurer Concentration | Reinsurer 2
Concentration Risk [Line Items]
Concentration risk, percentage of total	10.00%	11.00%
Reinsurance Recoverable On Unpaid And Paid Losses | Reinsurer Concentration | Reinsurer 3
Concentration Risk [Line Items]
Concentration risk, percentage of total	10.00%	7.00%
Reinsurance Recoverable On Unpaid And Paid Losses | Reinsurer Concentration | Top Ten Reinsurers | AM Best, A- Rating
Concentration Risk [Line Items]
Concentration risk, percentage of total	89.50%	88.80%
Gross Premiums Written | Customer Concentration
Concentration Risk [Line Items]
Concentration risk, percentage of total	43.00%	49.00%	52.00%
Concentration risk, number of brokers exceeding threshold | broker	3
Gross Premiums Written | Customer Concentration | Marsh & McLennan Companies Inc.
Concentration Risk [Line Items]
Concentration risk, percentage of total	17.00%	20.00%	21.00%
Gross Premiums Written | Customer Concentration | Aon plc
Concentration Risk [Line Items]
Concentration risk, percentage of total	17.00%	17.00%	19.00%
Gross Premiums Written | Customer Concentration | Willis Towers Watson PLC
Concentration Risk [Line Items]
Concentration risk, percentage of total	9.00%	12.00%	12.00%

COMMITMENTS AND CONTINGENCIES_3

COMMITMENTS AND CONTINGENCIES - Lease commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Rent expense related to operating leases	$ 33,000	$ 29,000	$ 25,000
Office Space
Future minimum lease payments under operating leases [Line Items]
2,019	28,240
2,020	25,331
2,021	27,025
2,022	28,012
2,023	23,801
Later years	118,497
Total future minimum lease payments	$ 250,906

COMMITMENTS AND CONTINGENCIES_4

COMMITMENTS AND CONTINGENCIES - Reinsurance purchase commitment and investments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Unrecorded Unconditional Purchase Obligation [Line Items]
Unfunded commitments related to other investments	$ 507,000	$ 414,000
Purchase commitment	39,000
Funds at Lloyd's	1,307,945	1,192,717
Collateral in Trust for third party agreements	1,510,416	2,085,443
CMBS
Unrecorded Unconditional Purchase Obligation [Line Items]
Purchase commitment	4,000	16,000
Lloyd's
Unrecorded Unconditional Purchase Obligation [Line Items]
Collateral in Trust for third party agreements	$ 1,300,000	$ 1,200,000

EARNINGS PER COMMON SHARE (Deta

EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings (loss) per common share
Net income (loss)									$ 43,021	$ (368,969)	$ 513,368
Less: Preferred share dividends									42,625	46,810	46,597
Less: Loss on repurchase of preferred shares									0	0	1,309
Net income (loss) available (attributable) to common shareholders	$ (198,448)	$ 43,439	$ 92,858	$ 62,546	$ (38,081)	$ (467,740)	$ 85,030	$ 5,014	$ 396	$ (415,779)	$ 465,462
Weighted average common shares outstanding (in shares)									83,501	84,108	90,772
Earnings (loss) per common share (in dollars per share)	$ (2.37)	$ 0.52	$ 1.11	$ 0.75	$ (0.46)	$ (5.61)	$ 1.01	$ 0.06	$ 0	$ (4.94)	$ 5.13
Earnings (loss) per diluted common share
Net income (loss) available (attributable) to common shareholders	$ (198,448)	$ 43,439	$ 92,858	$ 62,546	$ (38,081)	$ (467,740)	$ 85,030	$ 5,014	$ 396	$ (415,779)	$ 465,462
Weighted average common shares outstanding (in shares)									83,501	84,108	90,772
Share-based compensation plans (in shares)									506	0	775
Weighted average diluted common shares outstanding (in shares)									84,007	84,108	91,547
Diluted earnings (loss) per common share (in dollars per share)	$ (2.37)	$ 0.52	$ 1.11	$ 0.75	$ (0.46)	$ (5.61)	$ 1.01	$ 0.06	$ 0	$ (4.94)	$ 5.08
Weighted average anti-dilutive shares excluded from the dilutive computation (in shares)									245	702	170

SHAREHOLDERS' EQUITY - Common

SHAREHOLDERS' EQUITY - Common shares (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Authorized share capital, common (in shares)	800,000,000	800,000,000
Par value per share, common (in usd per share)	$ 0.0125	$ 0.0125
Common Shares Issued and Outstanding [Roll Forward]
Shares issued, balance at beginning of year (in shares)	176,580,000
Total shares issued at end of year (in shares)	176,580,000	176,580,000
Treasury Shares Issued and Outstanding [Roll Forward]
Treasury shares, balance at beginning of year (in shares)	(93,419,000)
Total treasury shares at end of year (in shares)	(92,994,000)	(93,419,000)
Total shares outstanding (in shares)	83,586,000	83,161,000
Cash dividends declared per common share (in usd per share)	$ 1.57	$ 1.53	$ 1.43
Common stocks
Common Shares Issued and Outstanding [Roll Forward]
Shares issued, balance at beginning of year (in shares)	176,580,000	176,580,000	176,240,000
Shares issued (in shares)	0	0	340,000
Total shares issued at end of year (in shares)	176,580,000	176,580,000	176,580,000
Treasury Shares Issued and Outstanding [Roll Forward]
Treasury shares, balance at beginning of year (in shares)	(93,419,000)	(90,139,000)	(80,174,000)
Shares repurchased (in shares)	(200,000)	(4,288,000)	(10,508,000)
Shares reissued from treasury (in shares)	625,000	1,008,000	543,000
Total treasury shares at end of year (in shares)	(92,994,000)	(93,419,000)	(90,139,000)
Total shares outstanding (in shares)	83,586,000	83,161,000	86,441,000

SHAREHOLDERS' EQUITY - Share r

SHAREHOLDERS' EQUITY - Share repurchase activities (Details) - Common stocks - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Treasury Shares [Line Items]
Total shares (in shares)	200	4,288	10,508
Total cost	$ 10,080	$ 285,858	$ 571,805
Average price per share (in usd per share)	$ 50.40	$ 66.67	$ 54.42
In the open market
Treasury Shares [Line Items]
Total shares (in shares)	0	3,932	10,241
Total cost	$ 0	$ 261,180	$ 557,476
Average price per share (in usd per share)	$ 0	$ 66.43	$ 54.44
From employees
Treasury Shares [Line Items]
Total shares (in shares)	200	356	267
Total cost	$ 10,080	$ 24,678	$ 14,329
Average price per share (in usd per share)	$ 50.40	$ 69.36	$ 53.74

SHAREHOLDERS' EQUITY - Acceler

SHAREHOLDERS' EQUITY - Accelerated share repurchase program (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 15, 2016	Aug. 31, 2015	Jan. 15, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Treasury Stock
Class of Stock [Line Items]
Total cost				$ 10,080	$ 285,858	$ 571,805
Additional paid-in capital
Class of Stock [Line Items]
Total cost				$ 0	$ 0	$ (60,000)
Accelerated Share Repurchase Agreement August 17 2015
Class of Stock [Line Items]
Total cost		$ 300,000
Total shares (in shares)	1,358,380	4,149,378	5,507,758		1,358,380
Accelerated Share Repurchases, initial repurchase percentage		80.00%
Average price per share (in usd per share)			$ 54.47
Accelerated Share Repurchase Agreement August 17 2015 | Treasury Stock
Class of Stock [Line Items]
Total cost	$ 60,000						$ 240,000
Accelerated Share Repurchase Agreement August 17 2015 | Additional paid-in capital
Class of Stock [Line Items]
Total cost							$ 60,000

SHAREHOLDERS' EQUITY - Preferr

SHAREHOLDERS' EQUITY - Preferred shares (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 27, 2016	Nov. 30, 2016	May 31, 2013	Apr. 30, 2012	Mar. 31, 2012	Nov. 30, 2005	Feb. 28, 2019	Feb. 28, 2018	Feb. 24, 2017	Nov. 30, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Apr. 17, 2017
Class of Stock [Line Items]
Aggregate cash payment to acquire preferred shares											$ 0	$ 351,074	$ 51,769
Loss on repurchase of preferred shares											0	0	$ 1,309
Preferred shares, aggregate liquidation value outstanding											$ 775,000	$ 775,000
Series B 7.50% Preferred Shares
Class of Stock [Line Items]
Preferred shares, aggregate liquidation value issued						$ 250,000
Preferred shares, dividend rate											7.50%
Preferred shares, par value per share (in usd per share)											$ 0.0125
Preferred shares, liquidation preference per share (in usd per share)											100
Preferred shares, redemption price per share (in usd per share)											$ 100
Preferred shares, purchase price per share (in usd per share)				$ 102.81
Preferred shares, number of shares redeemed (in shares)	28,430			2,471,570
Aggregate cash payment to acquire preferred shares				$ 254,000
Loss on repurchase of preferred shares				$ 9,000
Preferred shares, aggregate redemption price	$ 3,000
Series C 6.875% Preferred Shares
Class of Stock [Line Items]
Preferred shares, aggregate liquidation value issued					$ 400,000
Preferred shares, dividend rate											6.875%
Preferred shares, par value per share (in usd per share)											$ 0.0125
Preferred shares, liquidation preference per share (in usd per share)											25
Preferred shares, redemption price per share (in usd per share)											$ 25
Preferred shares, purchase price per share (in usd per share)		$ 25.67								$ 25.67
Preferred shares, number of shares redeemed (in shares)										1,957,045
Aggregate cash payment to acquire preferred shares										$ 50,000
Loss on repurchase of preferred shares										$ 1,000
Preferred shares, dividend declared per share (in usd per share)												$ 0.4297	$ 1.7188
Preferred shares, dividends paid per share (in usd per share)												0.4297	1.7188
Preferred shares, number of shares outstanding (in shares)														14,042,955
Preferred shares, aggregate liquidation value outstanding														$ 351,000
Series D 5.50% Preferred Shares
Class of Stock [Line Items]
Preferred shares, aggregate liquidation value issued			$ 225,000
Preferred shares, dividend rate											5.50%
Preferred shares, par value per share (in usd per share)											$ 0.0125
Preferred shares, liquidation preference per share (in usd per share)											25
Preferred shares, redemption price per share (in usd per share)											25
Preferred shares, dividend declared per share (in usd per share)											1.3750	1.3750	1.3750
Preferred shares, dividends paid per share (in usd per share)								$ 0.34375			$ 1.0313	1.0313	1.3750
Series E 5.50% Preferred Shares
Class of Stock [Line Items]
Preferred shares, aggregate liquidation value issued		$ 550,000
Preferred shares, dividend rate											5.50%
Preferred shares, par value per share (in usd per share)											$ 0.0125
Preferred shares, liquidation preference per share (in usd per share)											2,500
Preferred shares, redemption price per share (in usd per share)											2,500
Preferred shares, dividend declared per share (in usd per share)											137.50	137.50	$ 34.375
Preferred shares, dividends paid per share (in usd per share)								$ 34.3750	$ 34.375		$ 103.13	$ 103.13
Subsequent Event | Series D 5.50% Preferred Shares
Class of Stock [Line Items]
Preferred shares, dividends paid per share (in usd per share)							$ 0.34375
Subsequent Event | Series E 5.50% Preferred Shares
Class of Stock [Line Items]
Preferred shares, dividend declared per share (in usd per share)							$ 34.375

RETIREMENT PLANS (Details)

RETIREMENT PLANS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Retirement Benefits [Abstract]
Total pension expenses	$ 27	$ 24	$ 23

SHARE-BASED COMPENSATION - Long

SHARE-BASED COMPENSATION - Long term equity compensation plan narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)installmentshares	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	May 31, 2017shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash settled awards	$ 20,648	$ 21,535
Restricted Stock And Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock and cash settled awards vested	51,000	125,000	$ 67,000
Unrecognized compensation costs	$ 87,000	$ 94,000
Weighted average period for recognition of share based compensation	2 years 4 months 28 days	2 years 4 months 45 days
Share based compensation expense incurred	$ 54,000	$ 68,000	74,000
Tax benefit related to share-based compensation costs incurred	8,000	15,000	$ 16,000
Restricted Stock And Restricted Stock Units | Cash Settled
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash settled awards	$ 21,000	$ 22,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of installments | installment	4
Vesting period	3 years
Restricted Stock Units (RSUs) | Cash Settled
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of installments | installment	4
Restricted Stock Units (RSUs) | Cash Settled | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Performance Based Restricted Stock and Restricted Stock Units | Cash Settled | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
2007 Long-term Equity Compensation Plan | Share Settled
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of time subsequent to a change in control during which plan allows for accelerated vesting of awards for certain terminations	2 years
2007 Long-term Equity Compensation Plan | Service Based Restricted Stock And Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of installments | installment	4
2014 Long Term Equity Compensation Plan | Service Based Restricted Stock And Restricted Stock Units | Share Settled | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
2014 Long Term Equity Compensation Plan | Service Based Restricted Stock And Restricted Stock Units | Cash Settled | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
2014 Long Term Equity Compensation Plan | Restricted Stock And Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Fair value of restricted stock and cash settled awards vested		$ 44,000
2017 Long Term Equity Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares to be issued under the plan (in shares) | shares				3,400,000
Number of awards available for grant under plan (in shares) | shares	2,824,592

SHARE-BASED COMPENSATION - Shar

SHARE-BASED COMPENSATION - Share and cash settled awards (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Weighted Average Grant Date Fair Value
Liability for cash-settled units	$ 20,648	$ 21,535
Performance Based Restricted Stock and Restricted Stock Units | Share Settled
Number of restricted stock units
Nonvested restricted stock - beginning of year (in shares)	230,000	283,000
Granted (in shares)	104,000	87,000
Vested (in shares)	(87,000)	(119,000)
Forfeited (in shares)	(15,000)	(21,000)
Nonvested restricted stock - end of year (in shares)	232,000	230,000
Weighted Average Grant Date Fair Value
Weighted average grant date fair value - beginning of year (in usd per share)	$ 57.08	$ 51.27
Weighted average grant date fair value - granted (in usd per share)	48.89	64.58
Weighted average grant date fair value - vested (in usd per share)	54.71	49.14
Weighted average grant date fair value - forfeited (in usd per share)	53.80	55
Weighted average grant date fair value - end of year (in usd per share)	$ 54.54	$ 57.08
Performance Based Restricted Stock and Restricted Stock Units | Cash Settled
Number of restricted stock units
Nonvested restricted stock - beginning of year (in shares)	42,000	68,000
Granted (in shares)	0	15,000
Vested (in shares)	(12,000)	(38,000)
Forfeited (in shares)	(3,000)	(3,000)
Nonvested restricted stock - end of year (in shares)	27,000	42,000
Service Based Restricted Stock And Restricted Stock Units | Share Settled
Number of restricted stock units
Nonvested restricted stock - beginning of year (in shares)	1,355,000	1,593,000
Granted (in shares)	737,000	733,000
Vested (in shares)	(539,000)	(889,000)
Forfeited (in shares)	(142,000)	(82,000)
Nonvested restricted stock - end of year (in shares)	1,411,000	1,355,000
Weighted Average Grant Date Fair Value
Weighted average grant date fair value - beginning of year (in usd per share)	$ 57.09	$ 48.88
Weighted average grant date fair value - granted (in usd per share)	49.36	61.94
Weighted average grant date fair value - vested (in usd per share)	54.51	47.48
Weighted average grant date fair value - forfeited (in usd per share)	55.36	54.89
Weighted average grant date fair value - end of year (in usd per share)	$ 54.12	$ 57.09
Service Based Restricted Stock And Restricted Stock Units | Cash Settled
Number of restricted stock units
Nonvested restricted stock - beginning of year (in shares)	988,000	1,392,000
Granted (in shares)	473,000	432,000
Vested (in shares)	(390,000)	(763,000)
Forfeited (in shares)	(139,000)	(73,000)
Nonvested restricted stock - end of year (in shares)	932,000	988,000
Restricted Stock Units (RSUs)
Weighted Average Grant Date Fair Value
Vesting period	3 years
Cliff Vesting | Performance Based Restricted Stock and Restricted Stock Units | Cash Settled
Weighted Average Grant Date Fair Value
Vesting period	3 years
Cliff Vesting | Restricted Stock Units (RSUs) | Cash Settled
Weighted Average Grant Date Fair Value
Vesting period	3 years
2014 Long Term Equity Compensation Plan | Cliff Vesting | Service Based Restricted Stock And Restricted Stock Units | Share Settled
Number of restricted stock units
Vested (in shares)		(313,391)
Weighted Average Grant Date Fair Value
Vesting period		3 years
2014 Long Term Equity Compensation Plan | Cliff Vesting | Service Based Restricted Stock And Restricted Stock Units | Cash Settled
Number of restricted stock units
Vested (in shares)		(307,556)
Weighted Average Grant Date Fair Value
Vesting period		3 years

RELATED PARTY TRANSACTIONS (Det

RELATED PARTY TRANSACTIONS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Other investments		$ 787,787	$ 1,009,373
Ceded premiums		2,251,103	1,529,130	$ 1,217,234
Ceded losses and loss expenses		1,565,000	1,010,000	556,000
Insurance and reinsurance balances payable		1,338,991	899,064
Stone Point Group
Related Party Transaction [Line Items]
Fees paid to related party		2,000	2,000	3,000
NXT Capital II
Related Party Transaction [Line Items]
Other investments		18,000
NXT Capital III
Related Party Transaction [Line Items]
Other investments		20,000
NXT Capital
Related Party Transaction [Line Items]
Fees paid to related party		1,000	1,000	1,000
Freedom Consumer Credit Fund, LLC Series B
Related Party Transaction [Line Items]
Fees paid to related party		2,000	1,000
Other investments		50,000
Chairman
Related Party Transaction [Line Items]
Fees paid to related party		500	500	$ 600
Significant influence
Related Party Transaction [Line Items]
Other investments		450,000	451,000
Harrington Re
Related Party Transaction [Line Items]
Ceded premiums		194,000	213,000
Ceded losses and loss expenses		142,000	119,000
Reinsurance recoverable on unpaid and paid losses		363,000	152,000
Insurance and reinsurance balances payable		115,000	142,000
Ventures Re
Related Party Transaction [Line Items]
Ceded premiums		182,000	107,000
Ceded losses and loss expenses		138,000	126,000
Reinsurance recoverable on unpaid and paid losses		186,000	131,000
Insurance and reinsurance balances payable		$ 67,000	$ 17,000
Scenario, Forecast | Chairman
Related Party Transaction [Line Items]
Fees paid to related party	$ 500
Stone Point Group | NXT Capital
Related Party Transaction [Line Items]
Percentage ownership by related parties			43.00%
Stone Point Group | Pantheon
Related Party Transaction [Line Items]
Percentage ownership by related parties		14.50%

INCOME TAXES - Income tax expen

INCOME TAXES - Income tax expense and net tax assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income tax expense [Line Items]
Total income tax expense (benefit)	$ 42,000	$ (29,486)	$ (7,542)	$ 6,340
Net current tax receivables (payables)		9,683		3,540
Taxes payable	(639)		(639)
Net deferred tax assets	4,438	39,775	4,438	103,313
Net tax assets	$ 3,799	49,458	3,799	106,853
U.S.
Income tax expense [Line Items]
Current income tax expense (benefit)		(5,401)	(6,207)	606
Deferred income tax expense (benefit)		15,288	18,495	(1,829)
Europe
Income tax expense [Line Items]
Current income tax expense (benefit)		10,409	10,249	7,451
Deferred income tax expense (benefit)		(49,833)	(30,079)	112
Other
Income tax expense [Line Items]
Current income tax expense (benefit)		$ 51	$ 0	$ 0

INCOME TAXES - Deferred tax ass

INCOME TAXES - Deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2016
Deferred tax assets:
Discounting of net reserves for losses and loss expenses	$ 27,804	$ 37,440
Unearned premiums	25,188	40,447
Net unrealized investments losses	0	11,438
Operating and capital loss carryforwards	53,095	83,850
Accruals not currently deductible	31,560	32,589
Tax credits	29,929	8,672
Other deferred tax assets	15,047	9,195
Deferred tax assets before valuation allowance	182,623	223,631
Valuation allowance	(16,157)	(18,955)
Deferred tax assets net of valuation allowance	166,466	204,676
Deferred tax liabilities:
Deferred acquisition costs	(24,249)	(39,745)
Net unrealized investments gains	(8,033)	0
Amortization of VOBA, intangible assets and goodwill	(85,296)	(49,097)
Equalization reserves	(23,274)	(22,069)
Other deferred tax liabilities	(21,176)	(53,990)
Deferred tax liabilities	(162,028)	(164,901)
Net deferred tax assets	4,438	39,775	$ 103,313
Deferred tax asset, provisional income tax expense	41,600
Deferred tax liabilities, business acquisition		103,800
Lloyd's
Deferred tax assets:
Operating and capital loss carryforwards	$ 19,000	$ 68,000

INCOME TAXES - Operating and ca

INCOME TAXES - Operating and capital loss carryforwards and tax credits (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Singapore
Operating Loss And Tax Credit Carryforwards [Line Items]
Operating loss carryforwards	$ 79,445	$ 77,467
United Kingdom
Operating Loss And Tax Credit Carryforwards [Line Items]
Operating loss carryforwards	413,504	126,839
Tax credit	398	14,310
Ireland
Operating Loss And Tax Credit Carryforwards [Line Items]
Operating loss carryforwards	12,756	0
Tax credit	2,248	3,566
Ireland | Capital loss carryforward
Operating Loss And Tax Credit Carryforwards [Line Items]
Capital loss carryforwards	716	716
U.S.
Operating Loss And Tax Credit Carryforwards [Line Items]
Operating loss carryforwards	15,062	115,236
U.S. alternative minimum tax credit	6,026	12,052
Lloyd's | United Kingdom
Operating Loss And Tax Credit Carryforwards [Line Items]
Operating loss carryforwards	$ 403,000	$ 113,000

INCOME TAXES - Valuation allowa

INCOME TAXES - Valuation allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowance - beginning of year	$ 16,157
Valuation allowance - end of year	18,955	$ 16,157
Operating loss carryforwards
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Change in valuation allowance	198	(27,116)
Foreign tax credit
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Change in valuation allowance	(1,359)	267
U.K. branch assets and other foreign rate differentials
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Change in valuation allowance	(205)	1,006
U.S. alternative minimum tax credits
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Change in valuation allowance	(900)	900
Income tax expense
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowance - beginning of year	16,157	41,100
Valuation allowance - end of year	13,891	16,157
Accumulated other comprehensive income
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowance - beginning of year	0	0
Valuation allowance - end of year	5,064	0
Change in investment - related items
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Change in valuation allowance	$ 5,064	$ 0

INCOME TAXES - Effective tax ra

INCOME TAXES - Effective tax rate (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of effective tax rate (% of income before income taxes) [Line Items]
Unrecognized tax benefits	$ 0	$ 0
Income (loss) before income taxes
Bermuda (domestic)	181,597,000	(188,420,000)	$ 469,306,000
Foreign	(168,062,000)	(188,091,000)	50,402,000
Total income before income taxes	$ 13,535,000	$ (376,511,000)	$ 519,708,000
Reconciliation of effective tax rate (% of income before income taxes)
Expected tax rate	0.00%	0.00%	0.00%
Valuation allowance	(13.40%)	0.00%	0.20%
Net tax exempt income	(3.30%)	0.10%	(0.20%)
Other	5.90%	0.30%	0.30%
Actual tax rate	(217.90%)	2.00%	1.20%
U.S.
Reconciliation of effective tax rate (% of income before income taxes)
Foreign taxes at local expected rates:	65.70%	6.60%	(0.60%)
Change in enacted tax rate	0.00%	(11.10%)	0.00%
Europe
Reconciliation of effective tax rate (% of income before income taxes)
Foreign taxes at local expected rates:	(289.70%)	5.80%	1.50%
Change in enacted tax rate	16.90%	0.00%	0.00%
Other
Reconciliation of effective tax rate (% of income before income taxes)
Foreign taxes at local expected rates:	0.00%	0.30%	0.00%
Foreign Tax Credit And Change In Investment Related Items
Reconciliation of effective tax rate (% of income before income taxes) [Line Items]
Change in valuation allowance	$ (1,200,000)

OTHER COMPREHENSIVE INCOME (L_3

OTHER COMPREHENSIVE INCOME (LOSS) - Component of other comprehensive income (loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Before tax amount
Other comprehensive income (loss), before tax amount	$ (202,694)	$ 219,197	$ 69,950
Tax (expense) benefit
Other comprehensive income (loss), tax (expense) benefit	700	(4,974)	(3,326)
Net of tax amount
Other comprehensive income (loss), net of tax amount	(201,994)	214,223	66,624
Unrealized gains (losses) on available for sale investments, net of tax
Before tax amount
Unrealized investment gains (losses) arising during the year	(297,259)	211,151	10,165
Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income	105,730	(33,892)	60,423
Other comprehensive income (loss), before tax amount	(191,529)	177,259	70,588
Tax (expense) benefit
Unrealized investment gains (losses) arising during the year	5,528	(5,732)	(5,093)
Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income	(4,828)	758	1,767
Other comprehensive income (loss), tax (expense) benefit	700	(4,974)	(3,326)
Net of tax amount
Unrealized investment gains (losses) arising during the year	(291,731)	205,419	5,072
Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income	100,902	(33,134)	62,190
Other comprehensive income (loss), net of tax amount	(190,829)	172,285	67,262
Non-credit portion of OTTI losses
Before tax amount
Other comprehensive income (loss), before tax amount	0	0	0
Tax (expense) benefit
Other comprehensive income (loss), tax (expense) benefit	0	0	0
Net of tax amount
Other comprehensive income (loss), net of tax amount	0	0	0
Foreign currency translation adjustment
Before tax amount
Other comprehensive income (loss), before tax amount	(11,165)	41,938	(638)
Tax (expense) benefit
Other comprehensive income (loss), tax (expense) benefit	0	0	0
Net of tax amount
Other comprehensive income (loss), net of tax amount	$ (11,165)	$ 41,938	$ (638)

OTHER COMPREHENSIVE INCOME (L_4

OTHER COMPREHENSIVE INCOME (LOSS) - Reclassifications out of AOCI into net income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification out of accumulated comprehensive income into net income available to common shareholders [Line Items]
OTTI losses									$ (9,733)	$ (14,493)	$ (26,210)
Income (loss) before income taxes and interest in income (loss) of equity method investments									12,542	(368,109)	521,802
Foreign exchange gains									29,165	(134,737)	121,295
Income tax (expense) benefit					$ (42,000)				29,486	7,542	(6,340)
Net income (loss) available to common shareholders	$ (198,448)	$ 43,439	$ 92,858	$ 62,546	$ (38,081)	$ (467,740)	$ 85,030	$ 5,014	396	(415,779)	465,462
Non-cash foreign exchange losses									0	24,149	0
Unrealized 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)									(95,997)	48,385	(34,213)
OTTI losses									(9,733)	(14,493)	(26,210)
Income (loss) before income taxes and interest in income (loss) of equity method investments									(105,730)	33,892	(60,423)
Income tax (expense) benefit									4,828	(758)	(1,767)
Net income (loss) available to common shareholders									(100,902)	33,134	(62,190)
Cumulative foreign currency translation adjustments, net of tax | Reclassification out of Accumulated Other Comprehensive Income
Reclassification out of accumulated comprehensive income into net income available to common shareholders [Line Items]
Foreign exchange gains									0	(24,149)	0
Income tax (expense) benefit									0	0	0
Net income (loss) available to common shareholders									$ 0	$ (24,149)	$ 0

STATUTORY FINANCIAL INFORMATI_3

STATUTORY FINANCIAL INFORMATION (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)board_member	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Statutory Financial Information [Line Items]
Statutory net income	$ 268,000	$ (94,000)	$ 598,000
Bermuda
Statutory Financial Information [Line Items]
Required statutory capital and surplus	1,470,375	1,800,064
Available statutory capital and surplus	3,513,342	3,641,279
Minimum solvency margin amount	$ 100,000
Minimum solvency margin percentage of net written premiums	50.00%
Minimum solvency margin percentage of net reserves	15.00%
Minimum solvency margin percentage of ECR	25.00%
Limit - prior year's total statutory capital surplus (Bermuda)	25.00%
Number of directors required to sign affidavits in order to pay dividend/distribution greater than 25% of prior year statutory capital and surplus | board_member	2
Maximum dividend/distribution payable without regulatory approval	$ 900,000	900,000
Ireland
Statutory Financial Information [Line Items]
Required statutory capital and surplus	637,226	613,923
Available statutory capital and surplus	896,868	906,512
Maximum dividend/distribution payable with regulatory approval	37,000	52,000
U.S.
Statutory Financial Information [Line Items]
Required statutory capital and surplus	489,560	488,560
Available statutory capital and surplus	1,668,847	1,511,480
Maximum dividend/distribution payable without regulatory approval	$ 130,000	115,000
Maximum dividend limit - percentage of total statutory capital and surplus	10.00%
AXIS Syndicate 1686
Statutory Financial Information [Line Items]
Financial instruments, as collateral, at fair value	$ 715,000	557,000
Financial instruments, as collateral, released from restriction		1,600
AXIS Syndicate 1686 | Cash
Statutory Financial Information [Line Items]
Financial instruments, as collateral, at fair value	8,000	12,000
Syndicate 2,007
Statutory Financial Information [Line Items]
Financial instruments, as collateral, released from restriction		41,000
Syndicate 2007 | Equity securities
Statutory Financial Information [Line Items]
Financial instruments, as collateral, at fair value	40,000	59,000
Syndicate 2007 | Cash
Statutory Financial Information [Line Items]
Financial instruments, as collateral, at fair value	16,000	0
Syndicate 2007 | Fixed maturities and short-term investments
Statutory Financial Information [Line Items]
Financial instruments, as collateral, at fair value	$ 528,000	$ 564,000

UNAUDITED CONDENSED QUARTERLY_3

UNAUDITED CONDENSED QUARTERLY FINANCIAL DATA (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Net premiums earned	$ 1,214,469	$ 1,224,075	$ 1,185,548	$ 1,167,402	$ 1,211,495	$ 1,017,131	$ 981,431	$ 938,703	$ 4,791,495	$ 4,148,760	$ 3,705,625
Net investment income	113,128	114,421	109,960	100,999	100,908	95,169	106,063	98,664	438,507	400,805	353,335
Net investment losses	(72,667)	(17,628)	(45,093)	(14,830)	43,038	14,632	(4,392)	(25,050)	(150,218)	28,226	(60,525)
Underwriting income (loss)	(194,664)	59,026	115,726	143,737	26,130	(512,853)	57,012	16,385
Net income (loss) available (attributable) to common shareholders	$ (198,448)	$ 43,439	$ 92,858	$ 62,546	$ (38,081)	$ (467,740)	$ 85,030	$ 5,014	$ 396	$ (415,779)	$ 465,462
Basic earnings (loss) per common share (in dollars per share)	$ (2.37)	$ 0.52	$ 1.11	$ 0.75	$ (0.46)	$ (5.61)	$ 1.01	$ 0.06	$ 0	$ (4.94)	$ 5.13
Diluted earnings (loss) per common share (in dollars per share)	$ (2.37)	$ 0.52	$ 1.11	$ 0.75	$ (0.46)	$ (5.61)	$ 1.01	$ 0.06	$ 0	$ (4.94)	$ 5.08
Transaction and reorganization expenses	$ 19,000	$ 16,000	$ 19,000	$ 13,000	$ 21,000	$ 6,000
Amortization of value of business acquired	$ 23,000	$ 39,000	$ 53,000	$ 57,000	50,000				$ 172,332	$ 50,104	$ 0
Total income tax expense (benefit)					$ 42,000				$ (29,486)	$ (7,542)	$ 6,340

SCHEDULE I - SUMMARY OF INVES_2

SCHEDULE I - SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES (Details) $ in Thousands	Dec. 31, 2018USD ($)
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair value	$ 12,705,462
Amount shown on the balance sheet	13,155,560
Fixed maturities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized cost	11,616,312
Fair value	11,435,347
Amount shown on the balance sheet	11,435,347
U.S. government and agency
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized cost	1,520,142
Fair value	1,515,697
Amount shown on the balance sheet	1,515,697
Non-U.S. government
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized cost	507,550
Fair value	493,016
Amount shown on the balance sheet	493,016
Corporate debt
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized cost	4,990,279
Fair value	4,876,921
Amount shown on the balance sheet	4,876,921
Agency RMBS
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized cost	1,666,684
Fair value	1,643,308
Amount shown on the balance sheet	1,643,308
CMBS
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized cost	1,103,507
Fair value	1,092,530
Amount shown on the balance sheet	1,092,530
Non-Agency RMBS
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized cost	40,732
Fair value	40,687
Amount shown on the balance sheet	40,687
ABS
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized cost	1,651,350
Fair value	1,637,603
Amount shown on the balance sheet	1,637,603
Municipals
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Amortized cost	136,068
Fair value	135,585
Amount shown on the balance sheet	135,585
Mortgage loans
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair value	298,650
Amount shown on the balance sheet	298,650
Short-term investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair value	144,040
Amount shown on the balance sheet	144,040
Equity securities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair value	381,633
Amount shown on the balance sheet	381,633
Other Investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair value	445,792
Amount shown on the balance sheet	787,787
Equity method investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Fair value	0
Amount shown on the balance sheet	$ 108,103

SCHEDULE II - CONDENSED FINAN_2

SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY - BALANCE SHEETS (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents	$ 1,232,814	$ 948,626
Other assets	285,346	317,915
Total assets	24,132,566	24,760,177
Liabilities
Other liabilities	393,178	403,779
Total liabilities	19,102,495	19,418,913
Shareholders’ equity
Preferred shares	775,000	775,000
Common shares (shares issued 2018: 176,580; 2017: 176,580 shares outstanding 2018: 83,586; 2017: 83,161)	2,206	2,206
Additional paid-in capital	2,308,583	2,299,166
Accumulated other comprehensive income (loss)	(177,110)	92,382
Retained earnings	5,912,812	5,979,666
Treasury shares, at cost (2018: 92,994; 2017: 93,419)	(3,791,420)	(3,807,156)
Total shareholders’ equity	5,030,071	5,341,264
Total liabilities and shareholders’ equity	24,132,566	24,760,177
AXIS Capital Holdings Limited
Assets
Investments in subsidiaries	5,320,828	5,532,396
Cash and cash equivalents	3,099	10,541
Other assets	9,647	9,480
Total assets	5,333,574	5,552,417
Liabilities
Intercompany payable	247,992	160,950
Dividends payable	51,157	49,907
Other liabilities	4,354	296
Total liabilities	303,503	211,153
Shareholders’ equity
Preferred shares	775,000	775,000
Common shares (shares issued 2018: 176,580; 2017: 176,580 shares outstanding 2018: 83,586; 2017: 83,161)	2,206	2,206
Additional paid-in capital	2,308,583	2,299,166
Accumulated other comprehensive income (loss)	(177,110)	92,382
Retained earnings	5,912,812	5,979,666
Treasury shares, at cost (2018: 92,994; 2017: 93,419)	(3,791,420)	(3,807,156)
Total shareholders’ equity	5,030,071	5,341,264
Total liabilities and shareholders’ equity	$ 5,333,574	$ 5,552,417

SCHEDULE II - CONDENSED FINAN_3

SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY - BALANCE SHEETS, Additional Information (Details) - shares shares in Thousands	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Information of Parent Company [Line Items]
Common shares, shares issued (in shares)	176,580	176,580
Common shares, shares outstanding (in shares)	83,586	83,161
Treasury shares (in shares)	92,994	93,419
AXIS Capital Holdings Limited
Condensed Financial Information of Parent Company [Line Items]
Common shares, shares issued (in shares)	176,580	176,580
Common shares, shares outstanding (in shares)	83,586	83,161
Treasury shares (in shares)	92,994	93,419

SCHEDULE II - CONDENSED FINAN_4

SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY - BALANCE SHEETS, Footnotes (Details) - USD ($) $ in Millions	Feb. 15, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 06, 2017	Nov. 07, 2016
Senior Notes | 2010 AXIS Specialty Finance LLC Senior Notes
Condensed Financial Information of Parent Company [Line Items]
Interest rate		5.875%
Senior Notes | Senior Notes Due 2019 Axis Specialty Finance PLC 2014
Condensed Financial Information of Parent Company [Line Items]
Interest rate		2.65%
Senior Notes | Senior Notes Due 2045 Axis Specialty Finance PLC 2014
Condensed Financial Information of Parent Company [Line Items]
Interest rate		5.15%
Senior Notes | Senior Notes Axis Specialty Finance PLC 2017
Condensed Financial Information of Parent Company [Line Items]
Interest rate		4.00%
AXIS Capital Holdings Limited | Senior Notes | 2010 AXIS Specialty Finance LLC Senior Notes | Full and Unconditional Guarantee of Debt
Condensed Financial Information of Parent Company [Line Items]
Principal amount guaranteed		$ 500
Interest rate		5.875%
AXIS Capital Holdings Limited | Senior Notes | Senior Notes Due 2019 Axis Specialty Finance PLC 2014 | Full and Unconditional Guarantee of Debt
Condensed Financial Information of Parent Company [Line Items]
Principal amount guaranteed		$ 250
Interest rate		2.65%
AXIS Capital Holdings Limited | Senior Notes | Senior Notes Due 2045 Axis Specialty Finance PLC 2014 | Full and Unconditional Guarantee of Debt
Condensed Financial Information of Parent Company [Line Items]
Principal amount guaranteed		$ 250
Interest rate		5.15%
AXIS Capital Holdings Limited | Senior Notes | Senior Notes Axis Specialty Finance PLC 2017 | Full and Unconditional Guarantee of Debt
Condensed Financial Information of Parent Company [Line Items]
Principal amount guaranteed		$ 350
Interest rate		4.00%
AXIS Specialty Global Holdings [Member]
Condensed Financial Information of Parent Company [Line Items]
Capital contributions to subsidiary	$ 105
AXIS Specialty Finance LLC
Condensed Financial Information of Parent Company [Line Items]
Percentage ownership in subsidiary		100.00%
AXIS Specialty Finance LLC | Senior Notes | Full and Unconditional Guarantee of Debt
Condensed Financial Information of Parent Company [Line Items]
Percentage ownership in subsidiary		100.00%
AXIS Specialty Finance PLC
Condensed Financial Information of Parent Company [Line Items]
Percentage ownership in subsidiary				100.00%
AXIS Specialty Finance PLC | Senior Notes | Full and Unconditional Guarantee of Debt
Condensed Financial Information of Parent Company [Line Items]
Percentage ownership in subsidiary		100.00%
Promissory Note | AXIS Capital Holdings Limited
Condensed Financial Information of Parent Company [Line Items]
Interest rate			1.132%
Promissory note receivable from subsidiary					$ 368

SCHEDULE II - CONDENSED FINAN_5

SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY - OPERATIONS (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Total revenues									$ 5,090,406	$ 4,591,595	$ 4,005,657
Expenses
Net income (loss)									43,021	(368,969)	513,368
Preferred share dividends									42,625	46,810	46,597
Loss on repurchase of preferred shares									0	0	1,309
Net income (loss) available to common shareholders	$ (198,448)	$ 43,439	$ 92,858	$ 62,546	$ (38,081)	$ (467,740)	$ 85,030	$ 5,014	396	(415,779)	465,462
Comprehensive income (loss)									(158,973)	(154,746)	579,992
AXIS Capital Holdings Limited
Revenues
Net investment income (1)									900	2,116	656
Total revenues									900	2,116	656
Expenses
General and administrative expenses									29,250	34,933	39,909
Total expenses									29,250	34,933	39,909
Income (loss) before equity in net income (loss) of subsidiaries									(28,350)	(32,817)	(39,253)
Equity in net income (loss) of subsidiaries									71,371	(336,152)	552,621
Net income (loss)									43,021	(368,969)	513,368
Preferred share dividends									42,625	46,810	46,597
Loss on repurchase of preferred shares									0	0	1,309
Net income (loss) available to common shareholders									396	(415,779)	465,462
Comprehensive income (loss)									$ (158,973)	$ (154,746)	$ 579,992

SCHEDULE II - CONDENSED FINAN_6

SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY - CASH FLOWS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 43,021	$ (368,969)	$ 513,368
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Other items	26,452	(64,928)	(13,804)
Net cash provided by operating activities	10,773	259,229	406,724
Cash flows from investing activities:
Net cash provided by (used in) investing activities	638,554	391,510	(129,036)
Cash flows from financing activities:
Net proceeds from issuance of preferred shares	0	0	531,945
Repurchase of common shares - open market	0	(261,180)	(495,426)
Taxes paid on withholding shares	(10,080)	(24,678)	(14,329)
Dividends paid - common shares	(133,502)	(135,032)	(132,323)
Repurchase of preferred shares	0	(351,074)	(51,769)
Dividends paid - preferred shares	(42,625)	(52,844)	(39,909)
Proceeds from issuance of common shares	0	0	224
Net cash used in financing activities	(186,207)	(545,688)	(201,587)
Increase (decrease) in cash and cash equivalents	466,234	122,279	66,756
Cash, cash equivalents and restricted cash - beginning of year	1,363,786	1,241,507	1,174,751
Cash, cash equivalents and restricted cash - end of year	1,830,020	1,363,786	1,241,507
AXIS Capital Holdings Limited
Cash flows from operating activities:
Net income	43,021	(368,969)	513,368
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Equity in net income (loss) of subsidiaries	(71,371)	336,152	(552,621)
Change in intercompany payable	87,042	94,827	33,286
Dividends received from subsidiaries	200,000	400,000	550,000
Other items	(79,927)	4,988	17,807
Net cash provided by operating activities	178,765	466,998	561,840
Cash flows from investing activities:
Promissory note receivable from subsidiary	0	0	(368,252)
Capital returned by subsidiary	0	368,252	0
Net cash provided by (used in) investing activities	0	368,252	(368,252)
Cash flows from financing activities:
Net proceeds from issuance of preferred shares	0	0	531,945
Repurchase of common shares - open market	0	(261,180)	(495,426)
Taxes paid on withholding shares	(10,080)	(24,678)	(14,329)
Dividends paid - common shares	(133,502)	(135,032)	(132,323)
Repurchase of preferred shares	0	(351,074)	(51,769)
Dividends paid - preferred shares	(42,625)	(52,844)	(39,909)
Proceeds from issuance of common shares	0	0	224
Net cash used in financing activities	(186,207)	(824,808)	(201,587)
Increase (decrease) in cash and cash equivalents	(7,442)	10,442	(7,999)
Cash, cash equivalents and restricted cash - beginning of year	10,541	99	8,098
Cash, cash equivalents and restricted cash - end of year	$ 3,099	$ 10,541	$ 99

SCHEDULE III - SUPPLEMENTARY _2

SCHEDULE III - SUPPLEMENTARY INSURANCE INFORMATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplementary Insurance Information [Line Items]
Deferred acquisition costs	$ 566,622	$ 474,061	$ 438,636
Reserve for losses and loss expenses	12,280,769	12,997,553	9,697,827
Unearned premiums	3,635,758	3,641,399	2,969,498
Net premiums earned	4,791,495	4,148,760	3,705,625
Net Investment Income	438,507	400,805	353,335
Net losses and loss expenses	3,190,287	3,287,772	2,204,197
Acquisition costs	968,835	823,591	746,876
Other Operating Expenses	627,389	579,428	602,717
Net premiums written	4,658,962	4,027,143	3,752,974
Operating Segments | Insurance
Supplementary Insurance Information [Line Items]
Deferred acquisition costs	209,622	115,332	100,149
Reserve for losses and loss expenses	6,426,309	7,011,805	5,198,070
Unearned premiums	2,061,123	2,053,422	1,423,891
Net premiums earned	2,362,606	1,816,438	1,534,282
Net Investment Income	0	0	0
Net losses and loss expenses	1,494,323	1,465,427	977,771
Acquisition costs	399,193	270,229	206,619
Other Operating Expenses	395,252	325,368	327,351
Net premiums written	2,324,747	1,775,825	1,519,559
Operating Segments | Reinsurance
Supplementary Insurance Information [Line Items]
Deferred acquisition costs	357,000	358,729	338,487
Reserve for losses and loss expenses	5,854,460	5,985,748	4,499,757
Unearned premiums	1,574,635	1,587,977	1,545,607
Net premiums earned	2,428,889	2,332,322	2,171,343
Net Investment Income	0	0	0
Net losses and loss expenses	1,695,964	1,822,345	1,226,426
Acquisition costs	569,642	553,362	540,257
Other Operating Expenses	123,916	124,115	155,350
Net premiums written	2,334,215	2,251,318	2,233,415
Corporate
Supplementary Insurance Information [Line Items]
Deferred acquisition costs	0	0	0
Reserve for losses and loss expenses	0	0	0
Unearned premiums	0	0	0
Net premiums earned	0	0	0
Net Investment Income	438,507	400,805	353,335
Net losses and loss expenses	0	0	0
Acquisition costs	0	0	0
Other Operating Expenses	108,221	129,945	120,016
Net premiums written	$ 0	$ 0	$ 0

SCHEDULE IV - SUPPLEMENTARY R_2

SCHEDULE IV - SUPPLEMENTARY REINSURANCE INFORMATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplementary Insurance Information [Line Items]
DIRECT GROSS PREMIUM	$ 3,468,040	$ 2,423,126	$ 2,112,178
CEDED TO OTHER COMPANIES	2,251,103	1,529,130	1,217,234
ASSUMED FROM OTHER COMPANIES	3,442,025	3,133,147	2,858,030
NET AMOUNT	$ 4,658,962	$ 4,027,143	$ 3,752,974
PERCENTAGE OF AMOUNT ASSUMED TO NET	73.90%	77.80%	76.20%
Property and Casualty
Supplementary Insurance Information [Line Items]
DIRECT GROSS PREMIUM	$ 3,258,999	$ 2,228,022	$ 1,975,497
CEDED TO OTHER COMPANIES	2,163,417	1,523,662	1,215,775
ASSUMED FROM OTHER COMPANIES	3,074,906	2,814,173	2,564,606
NET AMOUNT	$ 4,170,488	$ 3,518,533	$ 3,324,328
PERCENTAGE OF AMOUNT ASSUMED TO NET	73.70%	80.00%	77.10%
Accident and health
Supplementary Insurance Information [Line Items]
DIRECT GROSS PREMIUM	$ 209,041	$ 195,104	$ 136,681
CEDED TO OTHER COMPANIES	87,686	5,468	1,459
ASSUMED FROM OTHER COMPANIES	367,119	318,974	293,424
NET AMOUNT	$ 488,474	$ 508,610	$ 428,646
PERCENTAGE OF AMOUNT ASSUMED TO NET	75.20%	62.70%	68.50%