AXIS Capital Holdings Limited (AXS) 10-Q 31 Oct 14 2014 Q3 Quarterly report Financial data

DOCUMENT_AND_ENTITY_INFORMATIO

DOCUMENT AND ENTITY INFORMATION	9 Months Ended
	Sep. 30, 2014	Oct. 24, 2014
DOCUMENT AND ENTITY INFORMATION [ABSTRACT]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Entity Registrant Name	'AXIS CAPITAL HOLDINGS LTD	'
Entity Central Index Key	'0001214816	'
Current Fiscal Year End Date	'--12-31	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	102,207,438

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets	'	'
Fixed maturities, available for sale, at fair value (Amortized cost 2014: $12,440,272; 2013: $11,987,146)	$12,444,684	$11,986,327
Equity securities, available for sale, at fair value (Cost 2014: $583,296; 2013: $566,219)	629,502	701,987
Other investments, at fair value	946,836	1,045,810
Short-term investments, at fair value and amortized cost	114,428	46,212
Total investments	14,135,450	13,780,336
Cash and cash equivalents	1,290,377	923,326
Restricted cash and cash equivalents	117,434	64,550
Accrued interest receivable	91,777	97,132
Insurance and reinsurance premium balances receivable	2,112,906	1,688,957
Reinsurance recoverable on unpaid and paid losses	1,947,529	1,929,988
Deferred acquisition costs	556,723	456,122
Prepaid reinsurance premiums	351,488	330,261
Receivable for investments sold	6,472	1,199
Goodwill and intangible assets	88,740	89,528
Other assets	266,151	273,385
Total assets	20,965,047	19,634,784
Liabilities	'	'
Reserve for losses and loss expenses	9,751,903	9,582,140
Unearned premiums	3,142,055	2,683,849
Insurance and reinsurance balances payable	244,815	234,412
Senior notes	1,490,498	995,855
Payable for investments purchased	189,684	21,744
Other liabilities	265,968	248,822
Total liabilities	15,084,923	13,766,822
Shareholders' equity	'	'
Preferred shares	627,843	627,843
Common shares (2014: 175,399; 2013: 174,134 shares issued and 2014: 100,827; 2013: 109,485 shares outstanding)	2,190	2,174
Additional paid-in capital	2,273,110	2,240,125
Accumulated other comprehensive income	22,935	117,825
Retained earnings	5,581,942	5,062,706
Treasury shares, at cost (2014: 74,572; 2013: 64,649 shares)	-2,689,531	-2,232,711
Total shareholders' equity attributable to AXIS Capital	5,818,489	5,817,962
Noncontrolling interests	61,635	50,000
Total shareholders' equity	5,880,124	5,867,962
Total liabilities and shareholders' equity	$20,965,047	$19,634,784

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Fixed maturities, available for sale, amortized cost	$12,440,272	$11,987,146
Equity securities, available for sale, cost	583,296	566,219
Short term investments, amortized cost	$114,428	$46,212
Common shares, shares issued	175,399	174,134
Common shares, shares outstanding	100,827	109,485
Treasury shares, shares	74,572	64,649

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues	'	'	'	'
Net premiums earned	$966,138	$945,242	$2,912,482	$2,765,154
Net investment income	66,562	103,429	264,171	295,450
Other insurance related income	7,702	725	12,468	1,756
Net realized investment gains (losses):	'	'	'	'
Other-than-temporary impairment (OTTI) losses	-9,431	-2,811	-12,121	-8,836
Other realized investment gains (losses)	86,879	-1,897	133,450	64,840
Total net realized investment gains (losses)	77,448	-4,708	121,329	56,004
Total revenues	1,117,850	1,044,688	3,310,450	3,118,364
Expenses	'	'	'	'
Net losses and loss expenses	552,064	501,522	1,662,097	1,582,835
Acquisition costs	185,950	173,682	549,848	488,892
General and administrative expenses	152,916	140,699	456,725	431,207
Foreign exchange losses (gains)	-72,292	56,860	-58,353	11,659
Interest expense and financing costs	20,344	15,260	56,913	46,355
Total expenses	838,982	888,023	2,667,230	2,560,948
Income before income taxes	278,868	156,665	643,220	557,416
Income tax expense (benefit)	-4,098	6,030	9,527	11,500
Net income	282,966	150,635	633,693	545,916
Amounts attributable to (from) noncontrolling interests	-6,160	0	-3,365	0
Net income attributable to AXIS Capital	289,126	150,635	637,058	545,916
Preferred share dividends	10,022	13,514	30,066	30,452
Loss on repurchase of preferred shares	0	0	0	3,081
Net income available to common shareholders	$279,104	$137,121	$606,992	$512,383
Net income per common share:	'	'	'	'
Basic net income	$2.71	$1.23	$5.74	$4.47
Diluted net income	$2.68	$1.21	$5.68	$4.41
Weighted average number of common shares outstanding - basic	102,945	111,676	105,683	114,606
Weighted average number of common shares outstanding - diluted	104,247	113,355	106,953	116,214
Cash dividends declared per common share	$0.27	$0.25	$0.81	$0.75

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net income	$282,966	$150,635	$633,693	$545,916
Other comprehensive income (loss), net of tax:	'	'	'	'
Unrealized gains (losses) arising during the period	-167,060	110,640	24,874	-170,786
Adjustment for reclassification of net realized investment gains and OTTI losses recognized in net income	-72,670	-8,657	-116,213	-46,571
Unrealized gains (losses) arising during the period, net of reclassification adjustment	-239,730	101,983	-91,339	-217,357
Non-credit portion of OTTI losses	0	0	0	0
Foreign currency translation adjustment	-10,000	3,635	-3,551	-14,892
Total other comprehensive income (loss), net of tax	-249,730	105,618	-94,890	-232,249
Comprehensive income	$33,236	$256,253	$538,803	$313,667

CONSOLIDATED_STATEMENTS_OF_CHA

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (USD $)	Total	Parent [Member]	Preferred shares [Member]	Common shares (par value) [Member]	Additional paid-in capital [Member]	Unrealized appreciation on available for sale investments, net of tax [Member]	Cumulative foreign currency translation adjustments, net of tax [Member]	Accumulated other comprehensive income [Member]	Retained earnings [Member]	Treasury shares, at cost [Member]	Noncontrolling interest [Member]
In Thousands
Total shareholders' equity at Dec. 31, 2012	'	'	$502,843	$2,146	$2,179,034	$348,328	$14,294	$362,622	$4,497,789	($1,764,673)	'
Shares issued	'	'	225,000	26	3,939	'	'	'	'	'	'
Cost of treasury shares reissued	'	'	'	'	-4,085	'	'	'	'	4,085	'
Issue costs on newly issued preferred shares	'	'	'	'	-6,551	'	'	'	'	'	'
Value of shares repurchased and retired during the period	'	'	-100,000	'	3,081	'	'	'	-3,081	'	'
Stock options exercised	'	'	'	'	13,029	'	'	'	'	'	'
Share-based compensation expense	'	'	'	'	37,379	'	'	'	'	'	'
Unrealized losses arising during the period, net of reclassification adjustment	-217,357	'	'	'	'	-217,357	'	'	'	'	'
Non-credit portion of OTTI losses	0	'	'	'	'	0	'	'	'	'	'
Foreign currency translation adjustments	-14,892	'	'	'	'	'	-14,892	'	'	'	'
Net income	545,916	'	'	'	'	'	'	'	545,916	'	'
Amounts attributable (to) from noncontrolling interests	0	'	'	'	'	'	'	'	0	'	'
Preferred share dividends	'	'	'	'	'	'	'	'	-30,452	'	'
Common share dividends	'	'	'	'	'	'	'	'	-88,456	'	'
Shares repurchased for treasury	'	'	'	'	'	'	'	'	'	-359,513	'
Total shareholders' equity at Sep. 30, 2013	5,787,829	5,787,829	627,843	2,172	2,225,826	130,971	-598	130,373	4,921,716	-2,120,101	0
Total shareholders' equity at Dec. 31, 2013	5,867,962	'	627,843	2,174	2,240,125	124,945	-7,120	117,825	5,062,706	-2,232,711	'
Shares issued	'	'	0	16	1,138	'	'	'	'	'	'
Cost of treasury shares reissued	'	'	'	'	-11,711	'	'	'	'	11,711	'
Issue costs on newly issued preferred shares	'	'	'	'	0	'	'	'	'	'	'
Value of shares repurchased and retired during the period	'	'	0	'	0	'	'	'	0	'	'
Stock options exercised	'	'	'	'	3,898	'	'	'	'	'	'
Share-based compensation expense	'	'	'	'	39,660	'	'	'	'	'	'
Unrealized losses arising during the period, net of reclassification adjustment	-91,339	'	'	'	'	-91,339	'	'	'	'	'
Non-credit portion of OTTI losses	0	'	'	'	'	0	'	'	'	'	'
Foreign currency translation adjustments	-3,551	'	'	'	'	'	-3,551	'	'	'	'
Net income	633,693	'	'	'	'	'	'	'	633,693	'	'
Amounts attributable (to) from noncontrolling interests	3,365	'	'	'	'	'	'	'	3,365	'	'
Preferred share dividends	'	'	'	'	'	'	'	'	-30,066	'	'
Common share dividends	'	'	'	'	'	'	'	'	-87,756	'	'
Shares repurchased for treasury	'	'	'	'	'	'	'	'	'	-468,531	'
Total shareholders' equity at Sep. 30, 2014	$5,880,124	$5,818,489	$627,843	$2,190	$2,273,110	$33,606	($10,671)	$22,935	$5,581,942	($2,689,531)	$61,635

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:	'	'
Net income	$633,693	$545,916
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Net realized investment gains	-121,329	-56,004
Net realized and unrealized gains on other investments	-45,868	-87,406
Amortization of fixed maturities	84,412	105,346
Other amortization and depreciation	17,669	16,725
Share-based compensation expense, net of cash payments	45,074	43,454
Changes in:	'	'
Accrued interest receivable	5,231	-1,065
Reinsurance recoverable balances	-26,419	-35,691
Deferred acquisition costs	-100,461	-115,754
Prepaid reinsurance premiums	-22,271	-24,604
Reserve for loss and loss expenses	184,881	425,785
Unearned premiums	458,058	535,609
Insurance and reinsurance balances, net	-412,603	-455,166
Other items	35,674	-8,519
Net cash provided by operating activities	735,741	888,626
Cash flows from investing activities:	'	'
Fixed maturities	-8,782,175	-9,236,509
Equity securities	-510,332	-191,209
Other investments	-60,272	-141,253
Short-term investments	-562,427	-158,049
Proceeds from the sale of:	'	'
Fixed maturities	7,625,717	7,779,177
Equity securities	597,820	279,468
Other investments	205,112	77,526
Short-term investments	429,679	131,907
Proceeds from redemption of fixed maturities	785,183	1,144,412
Proceeds from redemption of short-term investments	64,071	50,050
Purchase of other assets	-20,306	-17,402
Change in restricted cash and cash equivalents	-52,884	30,288
Net cash used in investing activities	-280,814	-251,594
Cash flows from financing activities:	'	'
Net proceeds from issuance of senior notes	494,344	0
Net proceeds from issuance of preferred shares	0	218,449
Repurchase of preferred shares	0	-100,000
Repurchase of common shares	-468,531	-359,513
Dividends paid - common shares	-90,092	-90,421
Dividends paid - preferred shares	-30,066	-29,171
Proceeds from issuance of common shares	5,052	16,995
Sale of shares to noncontrolling interests	25,000	0
Return of capital to noncontrolling interests	-10,000	0
Net cash used in financing activities	-74,293	-343,661
Effect of exchange rate changes on foreign currency cash and cash equivalents	-13,583	-3,635
Increase in cash and cash equivalents	367,051	289,736
Cash and cash equivalents - beginning of period	923,326	759,817
Cash and cash equivalents - end of period	$1,290,377	$1,049,553

BASIS_OF_PRESENTATION_AND_ACCO

BASIS OF PRESENTATION AND ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
BASIS OF PRESENTATION AND ACCOUNTING POLICIES [Text Block]	'
	Basis of Presentation
	These interim consolidated financial statements include the accounts of AXIS Capital Holdings Limited (“AXIS Capital”) and its subsidiaries (herein referred to as “we,” “us,” “our,” or the “Company”).
	The consolidated balance sheet at September 30, 2014 and the consolidated statements of operations, comprehensive income, shareholders' equity and cash flows for the periods ended September 30, 2014 and 2013 have not been audited. The balance sheet at December 31, 2013 is derived from our audited financial statements.
	These financial statements have been prepared in accordance with U.S. Generally Accepted Accounting Principles (“U.S. GAAP”) for interim financial information and with the Securities and Exchange Commission's (“SEC”) instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, these financial statements reflect all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of our financial position and results of operations for the periods presented. The results of operations for any interim period are not necessarily indicative of the results for a full year. All inter-company accounts and transactions have been eliminated.
	The following information should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2013. Tabular dollar and share amounts are in thousands, except per share amounts. All amounts are reported in U.S. dollars.
	Significant Accounting Policies
	There were no notable changes in our significant accounting policies subsequent to our Annual Report on Form 10-K for the year ended December 31, 2013.
	Recently Issued Accounting Standards Not Yet Adopted
	Share-Based Compensation
	In June 2014, the Financial Accounting Standards Board ("FASB") issued new guidance for share-based payments where a performance target could be achieved after the requisite service period has ended, requiring that compensation costs be recognized in the period in which it becomes probable that the performance target will be achieved and to represent the compensation cost attributable to the period(s) for which the requisite service has already been rendered. This guidance is effective for reporting periods beginning after December 15, 2015, with early adoption permitted. As the new guidance was issued to clarify treatment where there was divergence in accounting practice, the adoption of this guidance is not expected to impact our results of operations, financial condition or liquidity.

SEGMENT_INFORMATION

SEGMENT INFORMATION	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
SEGMENT INFORMATION [Text Block]	'
	Our underwriting operations are organized around our global underwriting platforms, AXIS Insurance and AXIS Re. Therefore we have determined that we have two reportable segments, insurance and reinsurance. We do not allocate our assets by segment, with the exception of goodwill and intangible assets, as we evaluate the underwriting results of each segment separately from the results of our investment portfolio.
	The following tables summarize the underwriting results of our reportable segments, as well as the carrying values of allocated goodwill and intangible assets:
			2014									2013
		Three months ended and at September 30,	Insurance			Reinsurance			Total			Insurance			Reinsurance			Total
		Gross premiums written	$	555,283		$	341,531		$	896,814		$	574,778		$	330,019		$	904,797
		Net premiums written	363,571			323,652			687,223			393,627			322,762			716,389
		Net premiums earned	461,805			504,333			966,138			448,072			497,170			945,242
		Other insurance related income	—			7,702			7,702			725			—			725
		Net losses and loss expenses	(289,207		)	(262,857		)	(552,064		)	(216,440		)	(285,082		)	(501,522		)
		Acquisition costs	(71,264		)	(114,686		)	(185,950		)	(61,087		)	(112,595		)	(173,682		)
		General and administrative expenses	(85,750		)	(36,612		)	(122,362		)	(82,548		)	(35,127		)	(117,675		)
		Underwriting income	$	15,584		$	97,880		113,464			$	88,722		$	64,366		153,088
		Corporate expenses							(30,554		)							(23,024		)
		Net investment income							66,562									103,429
		Net realized investment gains (losses)							77,448									(4,708		)
		Foreign exchange (losses) gains							72,292									(56,860		)
		Interest expense and financing costs							(20,344		)							(15,260		)
		Income before income taxes							$	278,868								$	156,665
		Net loss and loss expense ratio	62.6		%	52.1		%	57.1		%	48.3		%	57.3		%	53.1		%
		Acquisition cost ratio	15.4		%	22.7		%	19.2		%	13.6		%	22.6		%	18.4		%
		General and administrative expense ratio	18.6		%	7.3		%	15.9		%	18.5		%	7.2		%	14.8		%
		Combined ratio	96.6		%	82.1		%	92.2		%	80.4		%	87.1		%	86.3		%
		Goodwill and intangible assets	$	88,740		$	—		$	88,740		$	91,656		$	—		$	91,656
			2014									2013
		Nine months ended and at September 30,	Insurance			Reinsurance			Total			Insurance			Reinsurance			Total
		Gross premiums written	$	1,911,102		$	2,038,377		$	3,949,479		$	1,952,548		$	1,918,537		$	3,871,085
		Net premiums written	1,361,351			1,990,607			3,351,958			1,385,892			1,894,344			3,280,236
		Net premiums earned	1,368,683			1,543,799			2,912,482			1,272,297			1,492,857			2,765,154
		Other insurance related income	—			12,468			12,468			1,756			—			1,756
		Net losses and loss expenses	(859,093		)	(803,004		)	(1,662,097		)	(764,768		)	(818,067		)	(1,582,835		)
		Acquisition costs	(207,360		)	(342,488		)	(549,848		)	(177,097		)	(311,795		)	(488,892		)
		General and administrative expenses	(257,208		)	(106,987		)	(364,195		)	(257,962		)	(103,411		)	(361,373		)
		Underwriting income	$	45,022		$	303,788		348,810			$	74,226		$	259,584		333,810
		Corporate expenses							(92,530		)							(69,834		)
		Net investment income							264,171									295,450
		Net realized investment gains							121,329									56,004
		Foreign exchange (losses) gains							58,353									(11,659		)
		Interest expense and financing costs							(56,913		)							(46,355		)
		Income before income taxes							$	643,220								$	557,416
		Net loss and loss expense ratio	62.8		%	52		%	57.1		%	60.1		%	54.8		%	57.2		%
		Acquisition cost ratio	15.2		%	22.2		%	18.9		%	13.9		%	20.9		%	17.7		%
		General and administrative expense ratio	18.7		%	6.9		%	15.6		%	20.3		%	6.9		%	15.6		%
		Combined ratio	96.7		%	81.1		%	91.6		%	94.3		%	82.6		%	90.5		%
		Goodwill and intangible assets	$	88,740		$	—		$	88,740		$	91,656		$	—		$	91,656

INVESTMENTS

INVESTMENTS	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
INVESTMENTS [Text Block]	'
	a)     Fixed Maturities and Equities
	The amortized cost or cost and fair values of our fixed maturities and equities were as follows:
			Amortized			Gross				Gross			Fair			Non-credit
			Cost or			Unrealized				Unrealized			Value			OTTI
			Cost			Gains				Losses						in AOCI(5)
		At September 30, 2014
		Fixed maturities
		U.S. government and agency	$	1,545,328		$	1,564			$	(27,424	)	$	1,519,468		$	—
		Non-U.S. government	1,175,260			9,122				(45,460		)	1,138,922			—
		Corporate debt	4,240,910			47,065				(37,179		)	4,250,796			—
		Agency RMBS(1)	2,103,587			28,931				(11,571		)	2,120,947			—
		CMBS(2)	945,134			12,212				(2,829		)	954,517			—
		Non-Agency RMBS	75,452			3,531				(588		)	78,395			(888		)
		ABS(3)	1,443,932			3,775				(11,842		)	1,435,865			—
		Municipals(4)	910,669			36,181				(1,076		)	945,774			—
		Total fixed maturities	$	12,440,272		$	142,381			$	(137,969	)	$	12,444,684		$	(888	)
		Equity securities
		Common stocks	$	49,426		$	14,367			$	(648	)	$	63,145
		Exchange-traded funds	420,219			31,506				(1,049		)	450,676
		Non-U.S. bond mutual funds	113,651			2,030				—			115,681
		Total equity securities	$	583,296		$	47,903			$	(1,697	)	$	629,502
		At December 31, 2013
		Fixed maturities
		U.S. government and agency	$	1,421,245		$	1,405			$	(33,952	)	$	1,388,698		$	—
		Non-U.S. government	1,208,384			17,990				(49,992		)	1,176,382			—
		Corporate debt	3,533,585			84,881				(10,228		)	3,608,238			—
		Agency RMBS(1)	2,485,139			21,979				(58,291		)	2,448,827			—
		CMBS(2)	790,095			11,285				(3,966		)	797,414			—
		Non-Agency RMBS	65,590			2,375				(398		)	67,567			(868		)
		ABS(3)	955,274			6,871				(8,694		)	953,451			—
		Municipals(4)	1,527,834			32,432				(14,516		)	1,545,750			—
		Total fixed maturities	$	11,987,146		$	179,218			$	(180,037	)	$	11,986,327		$	(868	)
		Equity securities
		Common stocks	$	345,759		$	98,742			$	(6,183	)	$	438,318
		Exchange-traded funds	106,762			32,085				—			138,847
		Non-U.S. bond mutual funds	113,698			11,124				—			124,822
		Total equity securities	$	566,219		$	141,951			$	(6,183	)	$	701,987
	-1	Residential mortgage-backed securities (RMBS) originated by U.S. agencies.
	-2	Commercial mortgage-backed securities (CMBS).
	-3	Asset-backed securities (ABS) include debt tranched securities collateralized primarily by auto loans, student loans, credit cards, and other asset types. This asset class also includes collateralized loan obligations (CLOs) and collateralized debt obligations (CDOs).
	-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 of securities. It does not include the change in fair value subsequent to the impairment measurement date.
	In the normal course of investing activities, we actively manage allocations to non-controlling tranches of structured securities (variable interests) issued by VIEs. These structured securities include RMBS, CMBS and ABS and are included in the above table. Additionally, within our other investments portfolio, we also invest in limited partnerships (hedge funds) and CLO equity tranched securities, which are all variable interests issued by VIEs (see Note 3(b)). For these variable interests, we do not have the power to direct the activities that are most significant to the economic performance of the VIEs and accordingly we are not the primary beneficiary for any of these VIEs. Our maximum exposure to loss on these interests is limited to the amount of our investment. We have not provided financial or other support with respect to these structured securities other than our original investment.
	Contractual Maturities
	The contractual maturities of fixed maturities are shown below. 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.
			Amortized			Fair				% of Total
			Cost			Value				Fair Value
		At September 30, 2014
		Maturity
		Due in one year or less	$	550,351		$	549,150			4.5	%
		Due after one year through five years	5,250,453			5,266,397				42.3	%
		Due after five years through ten years	1,822,740			1,788,151				14.4	%
		Due after ten years	248,623			251,262				2	%
			7,872,167			7,854,960				63.2	%
		Agency RMBS	2,103,587			2,120,947				17	%
		CMBS	945,134			954,517				7.7	%
		Non-Agency RMBS	75,452			78,395				0.6	%
		ABS	1,443,932			1,435,865				11.5	%
		Total	$	12,440,272		$	12,444,684			100	%
		At December 31, 2013
		Maturity
		Due in one year or less	$	710,079		$	717,052			5.9	%
		Due after one year through five years	5,030,728			5,116,060				42.7	%
	Due after five years through ten years	1,852,877			1,791,835				14.9	%
	Due after ten years	97,364			94,121				0.8	%
		7,691,048			7,719,068				64.3	%
	Agency RMBS	2,485,139			2,448,827				20.4	%
	CMBS	790,095			797,414				6.7	%
	Non-Agency RMBS	65,590			67,567				0.6	%
	ABS	955,274			953,451				8	%
	Total	$	11,987,146		$	11,986,327			100	%
Gross Unrealized Losses
The following table summarizes fixed maturities and equities 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			Unrealized				Fair			Unrealized			Fair			Unrealized
		Value			Losses				Value			Losses			Value			Losses
	At September 30, 2014
	Fixed maturities
	U.S. government and agency	$	392,084		$	(23,150	)		$	864,003		$	(4,274	)	$	1,256,087		$	(27,424	)
	Non-U.S. government	148,526			(25,903		)		395,307			(19,557		)	543,833			(45,460		)
	Corporate debt	35,841			(2,608		)		2,006,740			(34,571		)	2,042,581			(37,179		)
	Agency RMBS	335,687			(9,617		)		469,445			(1,954		)	805,132			(11,571		)
	CMBS	77,827			(1,066		)		310,078			(1,763		)	387,905			(2,829		)
	Non-Agency RMBS	8,217			(524		)		3,087			(64		)	11,304			(588		)
	ABS	378,668			(8,122		)		640,305			(3,720		)	1,018,973			(11,842		)
	Municipals	39,450			(1,047		)		8,226			(29		)	47,676			(1,076		)
	Total fixed maturities	$	1,416,300		$	(72,037	)		$	4,697,191		$	(65,932	)	$	6,113,491		$	(137,969	)
	Equity securities
	Common stocks	$	1,828		$	(249	)		$	10,401		$	(399	)	$	12,229		$	(648	)
	Exchange-traded funds	—			—				56,074			(1,049		)	56,074			(1,049		)
	Total equity securities	$	1,828		$	(249	)		$	66,475		$	(1,448	)	$	68,303		$	(1,697	)
	At December 31, 2013
	Fixed maturities
	U.S. government and agency	$	—		$	—			$	982,307		$	(33,952	)	$	982,307		$	(33,952	)
	Non-U.S. government	35,577			(3,430		)		420,622			(46,562		)	456,199			(49,992		)
	Corporate debt	27,696			(802		)		606,592			(9,426		)	634,288			(10,228		)
	Agency RMBS	144,468			(5,247		)		1,478,527			(53,044		)	1,622,995			(58,291		)
	CMBS	13,319			(116		)		298,863			(3,850		)	312,182			(3,966		)
	Non-Agency RMBS	4,287			(315		)		5,319			(83		)	9,606			(398		)
	ABS	37,765			(2,941		)		553,803			(5,753		)	591,568			(8,694		)
	Municipals	8,408			(615		)		543,474			(13,901		)	551,882			(14,516		)
	Total fixed maturities	$	271,520		$	(13,466	)		$	4,889,507		$	(166,571	)	$	5,161,027		$	(180,037	)
	Equity securities
	Common stocks	$	3,499		$	(398	)		$	48,828		$	(5,785	)	$	52,327		$	(6,183	)
	Exchange-traded funds	—			—				—			—			—			—
	Total equity securities	$	3,499		$	(398	)		$	48,828		$	(5,785	)	$	52,327		$	(6,183	)
Fixed Maturities
At September 30, 2014, 1,306 fixed maturities (2013: 1,127) were in an unrealized loss position of $138 million (2013: $180 million), of which $14 million (2013: $2 million) was related to securities below investment grade or not rated.
At September 30, 2014, 281 (2013: 99) securities had been in a continuous unrealized loss position for 12 months or greater and had a fair value of $1,416 million (2013: $272 million). Following our credit impairment review, we concluded that these securities as well as the remaining securities in an unrealized loss position in the above table were temporarily impaired at September 30, 2014, and were expected to recover in value as the securities approach maturity. Further, at September 30, 2014, we did not intend to sell these securities in an unrealized loss position and it is more likely than not that we will not be required to sell these securities before the anticipated recovery of their amortized costs.
Equity Securities
At September 30, 2014, 9 securities (2013: 63) were in an unrealized loss position of $2 million (2013: $6 million).
At September 30, 2014, 2 (2013: 9) securities had been in a continuous unrealized loss position for 12 months or greater and had a fair value of $2 million (2013: $3 million). Based on our impairment review process and our ability and intent to hold these securities for a reasonable period of time sufficient for a full recovery, we concluded that the above equities in an unrealized loss position were temporarily impaired at September 30, 2014.
b) Other Investments
The following table provides a breakdown of our investments in hedge funds, direct lending funds and CLO Equities, together with additional information relating to the liquidity of each category:
		Fair Value						Redemption Frequency		Redemption
								(if currently eligible)		Notice Period
	At September 30, 2014
	Long/short equity funds	$	292,086		31	%		Quarterly, Semi-annually		45-60 days
	Multi-strategy funds	315,480			33	%		Quarterly, Semi-annually		60-95 days
	Event-driven funds	188,397			20	%		Quarterly, Annually		45-60 days
	Leveraged bank loan funds	9,904			1	%		Quarterly		65 days
	Direct lending funds	43,836			5	%		n/a		n/a
	CLO - Equities	97,133			10	%		n/a		n/a
	Total other investments	$	946,836		100	%
	At December 31, 2013
	Long/short equity funds	$	425,444		41	%		Monthly, Quarterly, Semi-annually		30-60 days
	Multi-strategy funds	285,155			27	%		Quarterly, Semi-annually		60-95 days
	Event-driven funds	190,458			18	%		Quarterly, Annually		45-60 days
	Leveraged bank loan funds	48,753			5	%		Quarterly		65 days
	Direct lending funds	22,134			2	%		n/a		n/a
	CLO - Equities	73,866			7	%		n/a		n/a
	Total other investments	$	1,045,810		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 both long and short investments in publicly-traded equities.
•	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.
•	Leveraged bank loan funds: Seek to achieve attractive returns by investing primarily in bank loan collateral that has limited interest rate risk exposure.
•	Direct lending funds: Seek to achieve attractive risk-adjusted returns, including current income generation, by investing in funds which provide financing directly to borrowers.
Two common redemption restrictions which may impact our ability to redeem our 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 2014 and 2013, neither of these restrictions impacted our redemption requests. At September 30, 2014, $71 million (2013: $99 million), representing 9% (2013: 10%) of our total hedge funds, relate to holdings where we are still within the lockup period. The expiration of these lockup periods range from September 2014 to April 2016.
At September 30, 2014, $6 million (2013: $11 million) was invested in hedge funds that are not accepting redemption requests. Of this amount, substantially all relates to a leveraged bank loan fund in a period of planned principal distributions. Based on market conditions and payments made to date, management's current expectation is that the distribution process will be completed in 2015.
At September 30, 2014, we have $67 million (2013: $88 million) of unfunded commitments within our other investments portfolio relating to our future investments 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 5-10 years and the General Partners of certain funds have the option to extend the term by up to three years.
During the fourth quarter of 2013, we made a $60 million commitment as a limited partner in a multi-strategy hedge fund. Once the full amount of committed capital has been called by the General Partner, the assets will not be fully returned until the completion of the fund's investment term which ends in December, 2018. The General Partner then has the option to extend the term by up to three years. At September 30, 2014, $41 million of our commitment remains unfunded and the current fair value of the funds called to date are included in the multi-strategy funds line of the table above.
During the third quarter of 2013, we made a $60 million commitment as a limited partner in a fund that invests primarily in CLO equities ("CLO fund").  We will not be eligible to redeem our investment until December 2017 but expect to receive interest distributions on a quarterly basis.  At September 30, 2014, the full amount of our commitment was funded and the current fair value of the funds called to date are included in the CLO - Equities line of the table above.  The CLO - Equities line also includes direct investment in the equity tranches of CLOs.
c) Net Investment Income
Net investment income was derived from the following sources:
		Three months ended September 30,							Nine months ended September 30,
		2014			2013				2014			2013
	Fixed maturities	$	74,996		$	74,691			$	226,475		$	218,877
	Other investments	(3,384		)	32,127				45,868			87,406
	Equity securities	2,022			3,871				9,609			8,419
	Cash and cash equivalents	2,081			382				9,127			2,915
	Short-term investments	141			127				600			1,056
	Gross investment income	75,856			111,198				291,679			318,673
	Investment expenses	(9,294		)	(7,769		)		(27,508		)	(23,223		)
	Net investment income	$	66,562		$	103,429			$	264,171		$	295,450
d) Net Realized Investment Gains (Losses)
The following table provides an analysis of net realized investment gains (losses):
		Three months ended September 30,							Nine months ended September 30,
		2014			2013				2014			2013
	Gross realized gains
	Fixed maturities and short-term investments	$	17,638		$	27,631			$	78,057		$	94,617
	Equities	81,888			11,985				133,764			48,266
	Gross realized gains	99,526			39,616				211,821			142,883
	Gross realized losses
	Fixed maturities and short-term investments	(8,527		)	(26,454		)		(56,623		)	(73,266		)
	Equities	(7,120		)	(2,001		)		(12,104		)	(9,011		)
	Gross realized losses	(15,647		)	(28,455		)		(68,727		)	(82,277		)
	Net OTTI recognized in earnings	(9,431		)	(2,811		)		(12,121		)	(8,836		)
	Change in fair value of investment derivatives(1)	3,000			(13,058		)		(9,644		)	4,234
	Net realized investment gains (losses)	$	77,448		$	(4,708	)		$	121,329		$	56,004
(1) Refer to Note 5 – Derivative Instruments
The following table summarizes the OTTI recognized in earnings by asset class:
		Three months ended September 30,							Nine months ended September 30,
		2014			2013				2014			2013
	Fixed maturities:
	Non-U.S. government	$	3,380		$	94			$	5,192		$	120
	Corporate debt	1,031			1,811				1,112			5,761
	Non-Agency RMBS	—			57				—			57
	ABS	—			—				56			129
	Municipals	418			639				418			639
		4,829			2,601				6,778			6,706
	Equity Securities
	Common stocks	—			207				741			1,607
	Exchange-traded funds	4,602			3				4,602			523
		4,602			210				5,343			2,130
	Total OTTI recognized in earnings	$	9,431		$	2,811			$	12,121		$	8,836
The following table provides a roll forward of the credit losses, before income taxes, for which a portion of the OTTI was recognized in AOCI:
		Three months ended September 30,							Nine months ended September 30,
		2014			2013				2014			2013
	Balance at beginning of period	$	1,581		$	1,699			$	1,594		$	1,809
	Credit impairments recognized on securities not previously impaired	—			—				—			—
	Additional credit impairments recognized on securities previously impaired	—			—				—			—
	Change in timing of future cash flows on securities previously impaired	—			—				—			—
	Intent to sell of securities previously impaired	—			—				—			—
	Securities sold/redeemed/matured	(23		)	(110		)		(36		)	(220		)
	Balance at end of period	$	1,558		$	1,589			$	1,558		$	1,589
e) Reverse Repurchase Agreements
At September 30, 2014, we held $101 million (2013: $34 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 on our consolidated balance sheet. 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, we receive principal and interest income.

FAIR_VALUE_MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
FAIR VALUE MEASUREMENTS [Text Block]	'
	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. We use a fair value hierarchy that gives the highest priority to quoted prices in active markets and the lowest priority to unobservable data. The hierarchy is broken down into three levels as follows:
	•	Level 1 - Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access.
	•	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 our 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 instruments categorized in Level 3. In periods of market dislocation, the observability of prices and inputs may be reduced for many instruments. This may lead us to change the selection of our valuation technique (from market to cash flow approach) or may cause us 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.
	We used the following valuation techniques and assumptions in estimating the fair value of our financial instruments as well as the general classification of such financial instruments pursuant to the above fair value hierarchy.
	Fixed Maturities
	At each valuation date, we use the market approach valuation technique to estimate the fair value of our 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 we maintain a vendor hierarchy by asset type based on historical pricing experience and vendor expertise. When prices are unavailable from pricing services, we obtain non-binding quotes from broker-dealers who are active in the corresponding markets.
	The following describes the significant inputs generally used to determine the fair value of our fixed maturities by asset class.
	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 our U.S. Treasury securities are based on unadjusted market prices in active markets, they are classified within Level 1. The fair values of U.S. government agency securities are priced using the spread above the risk-free yield curve. As the yields for the risk-free yield curve and the spreads for these securities are observable market inputs, the fair values of U.S. government agency securities are classified within Level 2.
	Non-U.S. government
	Non-U.S. government securities comprise bonds issued by non-U.S. governments and their agencies along with supranational organizations (collectively also known as sovereign debt securities). The fair value of these securities is based on prices obtained from international indices or a valuation model that includes the following inputs: 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 are observable market inputs, the fair value of non-U.S. government securities are classified within 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 these spreads and the yields for the risk-free yield curve are observable market inputs, the fair values of our corporate debt securities are classified within Level 2. Where pricing is unavailable from pricing services, we obtain 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, securities are classified within Level 3.
	MBS
	Our portfolio of RMBS and CMBS are originated by both agencies and non-agencies. The fair values of these securities are determined through the use of a pricing model (including Option Adjusted Spread) which uses prepayment speeds and spreads to determine the appropriate average life of the MBS. These spreads are generally obtained from the new issue market, secondary trading and broker-dealer quotes. As the significant inputs used to price MBS are observable market inputs, the fair values of the MBS are classified within Level 2. Where pricing is unavailable from pricing services, we obtain 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. These securities are classified within Level 3.
	ABS
	ABS include mostly investment-grade bonds backed by pools of loans with a variety of underlying collateral, including automobile loan receivables, student loans, credit card receivables, and CLO Debt originated by a variety of financial institutions. Similarly to MBS, the fair values of ABS are priced through the use of a model which uses prepayment speeds and spreads sourced primarily from the new issue market. As the significant inputs used to price ABS are observable market inputs, the fair values of ABS are classified within Level 2. Where pricing is unavailable from pricing services, we obtain non-binding quotes from broker-dealers or use a discounted cash flow model to estimate fair value. This is generally the case when there is a low volume of trading activity and current transactions are not orderly. These securities are priced within Level 3.
	Municipals
	Our municipal portfolio comprises revenue and general obligation bonds issued by U.S. domiciled state and municipal entities. The fair value of these securities is determined using spreads obtained from broker-dealers, trade prices and the new issue market. As the significant inputs used to price the municipals are observable market inputs, municipals are classified within Level 2.
	Equity Securities
	Equity securities include U.S. and non-U.S. common stocks, exchange-traded funds, and non-U.S. bond mutual funds. For common stocks and exchange-traded funds, we classified these within Level 1 as their fair values are based on unadjusted quoted market prices in active markets. Our investments in non-U.S. bond mutual funds have daily liquidity, with redemption based on the net asset value (NAV) of the funds. Accordingly, we have classified these investments as Level 2.
	Other Investments
	As a practical expedient, we estimate fair values for hedge funds, direct lending funds and the CLO fund using NAVs as advised by external fund managers or third party administrators. For each of these funds, the NAV is 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. For any funds for which we have not yet received a NAV concurrent with our period end date, we record an estimate of the change in fair value for the period subsequent to the most recent NAV. Such estimates are based on return estimates for the period between the most recently issued NAV and the period end date; these estimates are obtained from the relevant fund managers. Accordingly, we do not typically have a reporting lag in our fair value measurements for these funds. Historically, our valuation estimates incorporating these return estimates have not significantly diverged from the subsequent NAVs.
	Within the hedge fund, direct lending fund and CLO fund industries, there is a general lack of transparency necessary to facilitate a detailed independent assessment of the values placed on the securities underlying the NAV provided by the fund manager or fund administrator. To address this, on a quarterly basis, we perform a number of monitoring procedures designed to assist us in the assessment of the quality of the information provided by managers and 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 our fair value estimates against subsequently received NAVs. Backtesting involves comparing our previously reported values for each individual fund against NAVs per audited financial statements (for year-end values) and final NAVs from fund managers and fund administrators (for interim values).
	For our hedge fund investments with liquidity terms allowing us to fully redeem our holdings at the applicable NAV in the near term, we have classified these investments as Level 2. Certain investments in hedge funds, all of our direct lending funds and our CLO fund have redemption restrictions (see Note 3(b) for further details) that prevent us from redeeming in the near term and therefore we have classified these investments as Level 3.
	At September 30, 2014, our direct investments in CLO - Equities were classified within Level 3 as we estimated the fair value for these securities using an income approach valuation technique (discounted cash flow model) due to the lack of observable and relevant trades in the secondary markets.
	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. These securities are classified within 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
	Our foreign currency forward contracts, interest rate swaps and commodity contracts are customized to our economic hedging strategies and trade in the over-the-counter derivative market. We use the market approach valuation technique to estimate the fair value for these derivatives based on significant observable market inputs from third party pricing vendors, non-binding broker-dealer quotes and/or recent trading activity. Accordingly, we classified these derivatives within Level 2.
	We also participate in non-exchange traded derivative-based risk management products addressing weather risks. We use observable market inputs and unobservable inputs in combination with industry or internally-developed valuation and forecasting techniques to determine fair value. We classify these instruments within Level 3.
	Cash Settled Awards
	Cash settled awards comprise restricted stock units that form part of our compensation program. Although the fair value of these awards is determined using observable quoted market prices in active markets, the stock units themselves are not actively traded. Accordingly, we have classified these liabilities within Level 2.
	The table below presents the financial instruments measured at fair value on a recurring basis:
			Quoted Prices in				Significant			Significant			Total Fair
			Active Markets for				Other Observable			Unobservable			Value
			Identical Assets				Inputs			Inputs
			(Level 1)				(Level 2)			(Level 3)
		At September 30, 2014
		Assets
		Fixed maturities
		U.S. government and agency	$	1,390,737			$	128,731		$	—		$	1,519,468
		Non-U.S. government	—				1,138,922			—			1,138,922
		Corporate debt	—				4,250,796			—			4,250,796
		Agency RMBS	—				2,120,947			—			2,120,947
		CMBS	—				939,897			14,620			954,517
		Non-Agency RMBS	—				78,395			—			78,395
		ABS	—				1,375,330			60,535			1,435,865
		Municipals	—				945,774			—			945,774
			1,390,737				10,978,792			75,155			12,444,684
		Equity securities
		Common stocks	63,145				—			—			63,145
		Exchange-traded funds	450,676				—			—			450,676
		Non-U.S. bond mutual funds	—				115,681			—			115,681
			513,821				115,681			—			629,502
		Other investments
		Hedge funds	—				361,376			444,491			805,867
		Direct lending funds	—				—			43,836			43,836
		CLO - Equities	—				—			97,133			97,133
		—				361,376			585,460			946,836
	Short-term investments	—				114,428			—			114,428
	Derivative instruments (see Note 5)	—				16,591			228			16,819
	Total Assets	$	1,904,558			$	11,586,868		$	660,843		$	14,152,269
	Liabilities
	Derivative instruments (see Note 5)	$	—			$	10,469		$	7,646		$	18,115
	Cash settled awards (see Note 7)	—				14,106			—			14,106
	Total Liabilities	$	—			$	24,575		$	7,646		$	32,221
	At December 31, 2013
	Assets
	Fixed maturities
	U.S. government and agency	$	1,119,632			$	269,066		$	—		$	1,388,698
	Non-U.S. government	—				1,176,382			—			1,176,382
	Corporate debt	—				3,608,238			—			3,608,238
	Agency RMBS	—				2,448,827			—			2,448,827
	CMBS	—				793,396			4,018			797,414
	Non-Agency RMBS	—				67,567			—			67,567
	ABS	—				922,652			30,799			953,451
	Municipals	—				1,545,750			—			1,545,750
		1,119,632				10,831,878			34,817			11,986,327
	Equity securities
	Common stocks	438,318				—			—			438,318
	Exchange-traded funds	138,847				—			—			138,847
	Non-U.S. bond mutual funds	—				124,822			—			124,822
		577,165				124,822			—			701,987
	Other investments
	Hedge funds	—				488,755			461,055			949,810
	Direct lending funds	—				—			22,134			22,134
	CLO - Equities	—				—			73,866			73,866
		—				488,755			557,055			1,045,810
	Short-term investments	—				46,212			—			46,212
	Derivative instruments (see Note 5)	—				6,824			984			7,808
	Total Assets	$	1,696,797			$	11,498,491		$	592,856		$	13,788,144
	Liabilities
	Derivative instruments (see Note 5)	$	—			$	1,152		$	815		$	1,967
	Cash settled awards (see Note 7)	—				8,693			—			8,693
	Total Liabilities	$	—			$	9,845		$	815		$	10,660
During 2014 and 2013, we had no transfers between Levels 1 and 2.
Level 3 Fair Value Measurements
Except for hedge funds, direct lending funds and our CLO fund priced using NAV as a practical expedient and certain fixed maturities priced using broker-dealer quotes (underlying inputs are not available), the following table quantifies the significant unobservable inputs we have used in estimating fair value at September 30, 2014 for our investments classified as Level 3 in the fair value hierarchy. These significant unobservable inputs have not changed significantly from December 31, 2013. Where appropriate, this table has been reconciled back to the asset class total Level 3 holdings.
		Fair Value			Valuation Technique	Unobservable Input	Range	Weighted
								Average
	ABS - CLO Debt	$	17,810		Discounted cash flow	Credit spreads	3.40%	3.40%
						Illiquidity discount (1)	5.00%	5.00%
		42,725			Broker-dealer quote	n/a	n/a	n/a
		$	60,535
	Other investments - CLO - Equities	$	37,420		Discounted cash flow	Default rates	4.0% - 5.0%	4.30%
						Loss severity rate	53.50%	53.50%
						Collateral spreads	2.6% - 3.5%	3.30%
						Estimated maturity dates	3.2 - 4.4 years	3.9 years
		59,713			Net asset value	n/a	n/a	n/a
		$	97,133
	Derivatives - Weather derivatives, net	$	(7,418	)	Simulation model	Weather curve	33 - 2930(2)	n/a (3)
						Weather standard deviation	3 - 305(2)	n/a (3)
(1) Judgmentally determined based on limited trades of similar securities observed in the secondary markets.
(2) Measured in Heating Degree Days ("HDD") which is the number of degrees the daily temperature is below a reference temperature. The cumulative HDD for the duration of the derivatives contract is compared to the strike value to determine the necessary settlement.
-3	Due to the diversity of the portfolio, the range of unobservable inputs can be widespread; therefore, presentation of a weighted average is not useful. Weather parameters may include various temperature and/or precipitation measures that will naturally vary by geographic location of each counterparty's operations.
Our CLO Debt represent holdings of investment-grade debt tranches within collateralized loan obligations with underlying collateral of loans originated primarily by U.S. corporations. The CLO Debt in the table represent securities where broker-dealer quotes are unavailable so we estimate fair value through the use of a discounted cash flow model (income approach). This model estimates fair values by discounting the estimated cash flows based on current credit spreads for similar securities, derived from observable offer prices. As these securities are thinly traded in the secondary market, we apply an illiquidity discount to these discounted cash flows in developing our estimate of fair value. Significant increases (decreases) in either of the significant unobservable inputs (credit spread, illiquidity discount) in isolation would result in lower (higher) fair value estimates for our CLO Debt. The interrelationship between these inputs is insignificant. These inputs are updated on a quarterly basis and the reasonableness of the resulting prices is assessed through a comparison to observable offer prices for similar securities.
The CLO - Equities market continues to be mostly inactive with only a small number of transactions being observed in the market and fewer still involving transactions in our CLO - Equities. Accordingly, we continue to rely on the use of our internal discounted cash flow model (income approach) to estimate fair value of our direct investments in CLO - Equities. Of the significant inputs into this model, the default and loss severity rates are the most judgmental unobservable market inputs to which the valuation of CLO - Equities is most sensitive. A significant increase (decrease) in either of these significant inputs in isolation would result in lower (higher) fair value estimates for direct investments in our CLO - Equities and, in general, a change in default rate assumptions will be accompanied by a directionally similar change in loss severity rate assumptions. Collateral spreads and estimated maturity dates are less 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 higher (lower) fair value estimates for direct investments in our CLO - Equities.  In general, these inputs have no significant interrelationship with each other or with default and loss severity rates.
On a quarterly basis, our valuation processes for both CLO Debt and CLO - Equities include a review of the underlying cash flows and key assumptions used in the discounted cash flow models. We review and update the above significant unobservable inputs based on information obtained from secondary markets, including from the managers of the CLOs we hold. These inputs are the responsibility of management and, in order to ensure fair value measurement is applied consistently and in accordance with U.S. GAAP, we update our assumptions through regular communication with industry participants and ongoing monitoring of the deals in which we participate (e.g. default and loss severity rate trends), we maintain a current understanding of the market conditions, historical results, as well as emerging trends that may impact future cash flows. By maintaining this current understanding, we are able to assess the reasonableness of the inputs we ultimately use in our models.
Weather derivatives relate to non-exchange traded risk management products addressing weather risks. We use observable market inputs and unobservable inputs in combination with industry or internally-developed simulation models to determine fair value; these models may reference market price information for similar instruments. The pricing models are internally reviewed by Risk Management personnel prior to implementation and are reviewed periodically thereafter.
Observable and unobservable inputs to these models vary by contract type and would typically include the following:
•	Observable inputs: market prices for similar instruments, notional, option strike, term to expiry, contractual limits;
•	Unobservable inputs: correlation; and
•	Both observable and unobservable inputs: weather curves, weather standard deviation.
In general, weather curves are the most significant contributing input to fair value determination; changes in this variable can result in higher or lower fair value depending on the underlying position. In addition, changes in any or all of the unobservable inputs identified above may contribute positively or negatively to overall portfolio value. The correlation input will quantify the interrelationship, if any, amongst the other variables.
The following tables present changes in Level 3 for financial instruments measured at fair value on a recurring basis for the periods indicated:
		Opening				Transfers			Transfers			Included in			Included			Purchases		Sales			Settlements/			Closing		Change in
		Balance				into			out of			earnings (1)			in OCI (2)								Distributions			Balance		unrealized
						Level 3			Level 3																			investment
																												gain/(loss) (3)
	Three months ended September 30, 2014
	Fixed maturities
	Corporate debt	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
	Non-Agency RMBS	—				—			—			—			—			—		—			—			—		—
	CMBS	3,933				10,795			—			—			(31		)	—		—			(77		)	14,620		—
	ABS	30,883				42,039			—			—			882			—		—			(13,269		)	60,535		—
		34,816				52,834			—			—			851			—		—			(13,346		)	75,155		—
	Other investments
	Hedge funds	476,808				—			(32,255		)	(4,205		)	—			6,000		—			(1,857		)	444,491		(4,344		)
	Direct lending funds	33,467				—			—			627			—			10,086		—			(344		)	43,836		627
	CLO - Equities	91,106				—			—			5,729			—			6,674		—			(6,376		)	97,133		5,729
		601,381				—			(32,255		)	2,151			—			22,760		—			(8,577		)	585,460		2,012
	Other assets
	Derivative instruments	—				—			—			228			—			—		—			—			228		228
		—				—			—			228			—			—		—			—			228		228
	Total assets	$	636,197			$	52,834		$	(32,255	)	$	2,379		$	851		$	22,760	$	—		$	(21,923	)	$	660,843	$	2,240
	Other liabilities
	Derivative instruments	$	750			$	—		$	—		$	(272	)	$	—		$	7,587	$	—		$	(419	)	$	7,646	$	59
	Total liabilities	$	750			$	—		$	—		$	(272	)	$	—		$	7,587	$	—		$	(419	)	$	7,646	$	59
	Nine months ended September 30, 2014
	Fixed maturities
	Corporate debt	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
	Non-Agency RMBS	—				—			—			—			—			—		—			—			—		—
	CMBS	4,018				10,795			—			—			(74		)	—		—			(119		)	14,620		—
	ABS	30,799				42,167			—			—			1,060			—		—			(13,491		)	60,535		—
		34,817				52,962			—			—			986			—		—			(13,610		)	75,155		—
	Other investments
	Hedge funds	461,055				—			(32,255		)	16,718			—			13,500		—			(14,527		)	444,491		16,579
	Direct lending funds	22,134				—			—			1,546			—			20,831		—			(675		)	43,836		1,546
	CLO - Equities	73,866				—			—			17,060			—			25,941		—			(19,734		)	97,133		17,060
		557,055				—			(32,255		)	35,324			—			60,272		—			(34,936		)	585,460		35,185
	Other assets
	Derivative instruments	984				—			—			5,239			—			—		—			(5,995		)	228		228
		984				—			—			5,239			—			—		—			(5,995		)	228		228
	Total assets	$	592,856			$	52,962		$	(32,255	)	$	40,563		$	986		$	60,272	$	—		$	(54,541	)	$	660,843	$	35,413
	Other liabilities
	Derivative instruments	$	815			$	—		$	—		$	624		$	—		$	8,427	$	—		$	(2,220	)	$	7,646	$	59
	Total liabilities	$	815			$	—		$	—		$	624		$	—		$	8,427	$	—		$	(2,220	)	$	7,646	$	59
-1	Gains and losses included in earnings on fixed maturities are included in net realized investment gains (losses). Gains and (losses) included in earnings on other investments are included in net investment income. Gains (losses) on weather derivatives included in earnings are included in other insurance-related income.
-2	Gains and losses included in other comprehensive income (“OCI”) on fixed maturities are included in unrealized gains (losses) arising during the period.
-3	Change in unrealized investment gain (loss) relating to assets held at the reporting date.
		Opening				Transfers			Transfers			Included in			Included			Purchases		Sales			Settlements/			Closing		Change in
		Balance				into			out of			earnings (1)			in OCI (2)								Distributions			Balance		unrealized
						Level 3			Level 3																			investment
																												gain/(loss)  (3)
	Three months ended September 30, 2013
	Fixed maturities
	Corporate debt	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
	Non-Agency RMBS	—				—			—			—			—			—		—			—			—		—
	CMBS	11,785				—			(6,915		)	—			(96		)	—		—			(714		)	4,060		—
	ABS	54,125				34,700			—			—			1,048			—		—			(20,368		)	69,505		—
		65,910				34,700			(6,915		)	—			952			—		—			(21,082		)	73,565		—
	Other investments
	Hedge funds	444,220				—			—			13,233			—			—		—			(19,156		)	438,297		13,233
	Direct lending funds	4,232				—			—			75			—			8,708		—			—			13,015		75
	CLO - Equities	53,044				—			—			6,580			—			23,312		—			(12,736		)	70,200		6,580
		501,496				—			—			19,888			—			32,020		—			(31,892		)	521,512		19,888
	Other assets
	Derivative instruments	—				—			—			—			—			—		—			—			—		—
		—				—			—			—			—			—		—			—			—		—
	Total assets	$	567,406			$	34,700		$	(6,915	)	$	19,888		$	952		$	32,020	$	—		$	(52,974	)	$	595,077	$	19,888
	Other liabilities
	Derivative instruments	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
	Total liabilities	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
	Nine months ended September 30, 2013
	Fixed maturities
	Corporate debt	$	1,550			$	—		$	—		$	1,550		$	—		$	—	$	(3,100	)	$	—		$	—	$	—
	Non-Agency RMBS	1,110				—			(1,223		)	—			135			—		—			(22		)	—		—
	CMBS	4,296				8,382			(6,915		)	—			(243		)	—		—			(1,460		)	4,060		—
	ABS	63,975				34,700			(213,212		)	(112		)	2,029			212,889		(10,190		)	(20,574		)	69,505		—
		70,931				43,082			(221,350		)	1,438			1,921			212,889		(13,290		)	(22,056		)	73,565		—
	Other investments
	Hedge funds	359,996				29,953			—			38,723			—			50,000		—			(40,375		)	438,297		38,723
	Direct lending funds	—				—			—			75			—			12,940		—			—			13,015		75
	CLO - Equities	62,435				—			—			21,605			—			23,312		—			(37,152		)	70,200		21,605
		422,431				29,953			—			60,403			—			86,252		—			(77,527		)	521,512		60,403
	Other assets
	Derivative instruments	—				—			—			—			—			—		—			—			—		—
		—				—			—			—			—			—		—			—			—		—
	Total assets	$	493,362			$	73,035		$	(221,350	)	$	61,841		$	1,921		$	299,141	$	(13,290	)	$	(99,583	)	$	595,077	$	60,403
	Other liabilities
	Derivative instruments	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
	Total liabilities	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
-1	Gains and losses included in earnings on fixed maturities are included in net realized investment gains (losses). Gains and (losses) included in earnings on other investments are included in net investment income. Gains (losses) on weather derivatives included in earnings are included in other insurance-related income.
-2	Gains and losses included in other comprehensive income (“OCI”) on fixed maturities are included in unrealized gains (losses) arising during the period.
-3	Change in unrealized investment gain (loss) relating to assets held at the reporting date.
The transfers into and out of fair value hierarchy levels reflect the fair value of the securities at the end of the reporting period.
Transfers into Level 3 from Level 2
The transfers to Level 3 from Level 2 made during the three and nine months ended September 30, 2014 were primarily due to the lack of observable market inputs and multiple quotes from pricing vendors and broker-dealers for certain fixed maturities. The transfers to Level 3 from Level 2 made during the three and nine months ended September 30, 2013 were primarily due to redemption provisions in hedge fund holdings and 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 to Level 2 from Level 3 made during the three and nine months ended September 30, 2014 related to certain hedge funds where we have the ability to liquidate holdings at the reported NAV in the near term due to the expiry of lockup provisions. The transfers to Level 2 from Level 3 made during the three and nine months ended September 30, 2013 were primarily due to the availability of observable market inputs and multiple quotes from pricing vendors and broker-dealers on CLO Debt securities purchased during the first quarter of 2013.
Financial Instruments Not Carried at Fair Value
U.S. GAAP guidance over disclosures about the fair value of financial instruments are also applicable to financial instruments not carried at fair value, except for certain financial instruments, including insurance contracts.
The carrying values of 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 at September 30, 2014, due to their respective short maturities. As these financial instruments are not actively traded, their respective fair values are classified within Level 2.
At September 30, 2014, our senior notes are recorded at amortized cost with a carrying value of $1,490 million (2013: $996 million) and have a fair value of $1,593 million (2013: $1,073 million). The fair values of these securities were obtained from a third party pricing service and pricing was based on 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 these spreads and the yields for the risk-free yield curve are observable market inputs, the fair values of our senior notes are classified within Level 2.

DERIVATIVE_INSTRUMENTS

DERIVATIVE INSTRUMENTS	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
DERIVATIVE INSTRUMENTS [Text Block]	'
	The following table summarizes the balance sheet classification of derivatives recorded at fair values. The notional amount of derivative contracts represents the basis upon which pay or receive amounts are calculated and is presented in the table to quantify the volume of our derivative activities. Notional amounts are not reflective of credit risk.
			September 30, 2014												December 31, 2013
			Derivative				Derivative				Derivative				Derivative				Derivative		Derivative
			Notional				Asset				Liability				Notional				Asset		Liability
			Amount				Fair				Fair				Amount				Fair		Fair
							Value(1)				Value(1)								Value(1)		Value(1)
		Derivatives not designated as hedging instruments
		Relating to investment portfolio:
		Foreign exchange forward contracts	$	167,105			$	5,175			$	11			$	254,023			$	1,214	$	1,032
		Interest rate swaps	346,250				—				624				281,250				873		—
		Relating to underwriting portfolio:
		Foreign exchange forward contracts	616,539				316				9,834				390,663				4,737		120
		Weather-related contracts	53,017				228				7,646				24,451				984		815
		Commodity contracts	$	100,850			11,100				—				$	—			—		—
		Total derivatives					$	16,819			$	18,115							$	7,808	$	1,967
	-1	Asset and liability derivatives are classified within other assets and other liabilities in the Consolidated Balance Sheets.
	Offsetting Assets and Liabilities
	Our 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. The table below presents a reconciliation of our gross derivative assets and liabilities to the net amounts presented in our Consolidated Balance Sheets, with the difference being attributable to the impact of master netting agreements.
			September 30, 2014										December 31, 2013
			Gross Amounts			Gross Amounts Offset			Net				Gross Amounts			Gross Amounts Offset			Net
									Amounts(1)										Amounts(1)
		Derivative assets	$	25,823		$	(9,004	)	$	16,819			$	9,796		$	(1,988	)	$	7,808
		Derivative liabilities	$	27,119		$	(9,004	)	$	18,115			$	3,955		$	(1,988	)	$	1,967
	-1	Net asset and liability derivatives are classified within other assets and other liabilities in the Consolidated Balance Sheets.
	Refer to Note 3 - Investments for information on reverse repurchase agreements.
	Derivative Instruments not Designated as Hedging Instruments
	a) Relating to Investment Portfolio
	Foreign Currency Risk
	Within our investment portfolio we are exposed to foreign currency risk. Accordingly, the fair values for our investment portfolio are partially influenced by the change in foreign exchange rates. We 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.
	In addition, our external equity investment managers have the discretion to hold foreign currency exposures as part of their total return strategy.
	The decrease in the notional amount of investment-related derivatives since December 31, 2013 was due to a decrease in sterling and Canadian dollar-denominated fixed maturities being hedged.
	Interest Rate Risk
	Our investment portfolio contains a large percentage of fixed maturities which exposes us to significant interest rate risk. As part of our overall management of this risk, we may use interest rate swaps. The interest rate swaps held at September 30, 2014 convert part of our overall fixed rate exposure to a variable rate exposure which effectively reduces the duration of our overall portfolio.
	b) Relating to Underwriting Portfolio
	Foreign Currency Risk
	Our (re)insurance subsidiaries and branches operate in various foreign countries. Consequently, some of our business is written in currencies other than the U.S. dollar and, therefore, our underwriting portfolio is exposed to significant foreign currency risk. We manage foreign currency risk by seeking to match our foreign-denominated net liabilities under (re)insurance contracts with cash and investments that are denominated in such currencies. We may also use derivative instruments, specifically forward contracts and currency options, to economically hedge foreign currency exposures.
	The increase in the notional amount of underwriting related derivatives since December 31, 2013, was primarily due to new business written in the first half of 2014.
	Weather Risk
	During 2013, we 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 consists 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 wishes to minimize the upfront payment, these transactions may be structured as swaps or collars. In general, our portfolio of such derivative contracts is of short duration, with contracts being predominantly seasonal in nature. In order to economically hedge a portion of this portfolio, we may also purchase weather derivatives.
	Commodity Risk
	Within our (re)insurance portfolio we are exposed to commodity price risk. During 2014, we began to hedge this price risk by entering into commodity derivative contracts.
	The total unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges were as follows:
			Location of Gain (Loss) Recognized in Income on Derivative	Three months ended September 30,								Nine months ended September 30,
				2014				2013				2014				2013
		Derivatives not designated as hedging instruments
		Relating to investment portfolio:
		Foreign exchange forward contracts	Net realized investment gains (losses)	$	7,034			$	(7,802	)		$	3,350			$	9,222
		Interest rate swaps	Net realized investment gains (losses)	(4,034		)		(5,256		)		(12,994		)		(4,988		)
		Relating to underwriting portfolio:
		Foreign exchange forward contracts	Foreign exchange losses (gains)	(21,915		)		(2,697		)		(8,784		)		(4,895		)
		Weather-related contracts	Other insurance related income	668				—				4,730				—
		Commodity contracts	Other insurance related income	7,530				—				9,243				—
		Total		$	(10,717	)		$	(15,755	)		$	(4,455	)		$	(661	)

RESERVE_FOR_LOSSES_AND_LOSS_EX

RESERVE FOR LOSSES AND LOSS EXPENSES	9 Months Ended
	Sep. 30, 2014
Insurance Loss Reserves [Abstract]	'
RESERVE FOR LOSSES AND LOSS EXPENSES [Text Block]	'
	The following table presents a reconciliation of our beginning and ending gross reserve for losses and loss expenses and net reserve for unpaid losses and loss expenses for the periods indicated:
		Nine months ended September 30,	2014			2013
		Gross reserve for losses and loss expenses, beginning of period	$	9,582,140		$	9,058,731
		Less reinsurance recoverable on unpaid losses, beginning of period	(1,900,112		)	(1,825,617		)
		Net reserve for unpaid losses and loss expenses, beginning of period	7,682,028			7,233,114
		Net incurred losses and loss expenses related to:
		Current year	1,855,482			1,759,483
		Prior years	(193,385		)	(176,648		)
			1,662,097			1,582,835
		Net paid losses and loss expenses related to:
		Current year	(202,364		)	(168,564		)
		Prior years	(1,165,215		)	(1,028,401		)
			(1,367,579		)	(1,196,965		)
		Foreign exchange and other	(139,313		)	(17,265		)
		Net reserve for unpaid losses and loss expenses, end of period	7,837,233			7,601,719
		Reinsurance recoverable on unpaid losses, end of period	1,914,670			1,882,797
		Gross reserve for losses and loss expenses, end of period	$	9,751,903		$	9,484,516
	Prior year reserve development arises from changes to loss and loss expense estimates recognized in the current year but relating to losses incurred in previous calendar years. Such development is summarized by segment in the following table:
			Three months ended September 30,						Nine months ended September 30,
			2014			2013			2014		2013
		Insurance	$	9,488		$	34,065		$	54,059	$	46,355
		Reinsurance	55,050			45,970			139,326		130,293
		Total	$	64,538		$	80,035		$	193,385	$	176,648
	The majority of the net favorable prior year reserve development in each period related to short-tail lines of business. Net favorable prior year reserve development for professional and liability reinsurance lines in the three and nine months ended September 30, 2014 and 2013 also contributed and was partially offset by unfavorable prior year reserve development in the liability insurance lines.
	The underlying exposures in the property, marine and aviation reserving classes within our insurance segment and the property reserving class within our reinsurance segment largely relate to short-tail business. Development from these classes contributed $61 million and $57 million of the total net favorable prior year reserve development for the three months ended September 30, 2014 and 2013, respectively. For the nine months ended September 30, 2014 and 2013, these short-tail lines contributed $162 million and $119 million, respectively, of net favorable prior year reserve development. The net favorable development for these classes primarily reflected the recognition of better than expected loss emergence.
	In the first quarter of 2013, we began to give weight to actuarial methods that reflect our actual experience for liability reinsurance business, as we believe that our older accident years are now at a stage of expected development where such methods will produce meaningful actuarial indications. Favorable development was recognized of $26 million in the three months ended September 30, 2013 and $12 million and $64 million in the nine months ended September 30, 2014 and 2013, respectively, primarily reflecting the greater weight management is giving to experience based indications and our experience which has been favorable for the 2005 through 2008 accident years.
	Our medium-tail business consists primarily of professional insurance and reinsurance lines and credit and surety reinsurance business. Our professional lines reinsurance business contributed further net favorable prior year reserve development of $10 million in both the three months ended September 30, 2014 and 2013 and $22 million and $20 million in the nine months ended September 30, 2014 and 2013, respectively. This prior year reserve development was driven by increased weight being given to experience based actuarial methods in selecting our ultimate loss estimates for accident years 2010 and prior. As our loss experience has generally been better than expected, this resulted in the recognition of favorable development.
	In the three months ended September 30, 2014 we recorded adverse prior year reserve development of $14 million in our insurance liability lines relating primarily to an increase in loss estimates for two specific claims. Our credit and surety line recorded an adverse development of $15 million in the three months ended September 30, 2013 primarily reflecting recent claim developments on certain European bond exposures.
	The frequency and severity of natural catastrophe and weather activity was high in recent years and our September 30, 2014 net reserve for losses and loss expenses continues to include estimated amounts for numerous events. We caution that the magnitude and/or complexity of losses arising from certain of these events, in particular Storm Sandy, the 2011 Japanese earthquake and tsunami and 2010 and 2011 New Zealand earthquakes, inherently increase the level of uncertainty and, therefore, the level of management judgment involved in arriving at our estimated net reserves for losses and loss expenses. As a result, our actual losses for these events may ultimately differ materially from our current estimates.

SHAREBASED_COMPENSATION

SHARE-BASED COMPENSATION	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
SHARE-BASED COMPENSATION [Text Block]	'
	For the three months ended September 30, 2014, we incurred share-based compensation costs of $18 million (2013: $14 million) and recorded associated tax benefits of $4 million (2013: $3 million). For the nine months ended September 30, 2014, we incurred share-based compensation costs of $54 million (2013: $45 million) and recorded tax benefits thereon of $10 million (2013: $8 million).
	The fair value of shares vested during the nine months ended September 30, 2014 was $66 million (2013: $68 million). At September 30, 2014 there were $130 million of unrecognized share-based compensation costs, which are expected to be recognized over the weighted average period of 2.4 years.
	Awards to settle in shares
	The following table provides a reconciliation of the beginning and ending balance of nonvested restricted stock (including restricted stock units) for the nine months ended September 30, 2014:
			Performance-based Stock Awards			Service-based Stock Awards
			Number of	Weighted Average		Number of		Weighted Average
			Restricted	Grant Date		Restricted		Grant Date
			Stock	Fair Value		Stock		Fair Value
		Nonvested restricted stock - beginning of period	283	$	35.74	3,430		$	34.72
		Granted	68	44.33		1,038		44.42
		Vested	—	—		(1,440	)	33.82
		Forfeited	—	—		(193	)	36.77
		Nonvested restricted stock - end of period	351	$	37.41	2,835		$	38.54
	Cash-settled awards
	During 2014 we also granted 1,003,226 restricted stock units that will settle in cash rather than shares when the awards ultimately vest; of which 22,837 restricted stock units are performance based and 980,389 restricted stock units are service based. At September 30, 2014, the corresponding liability for cash-settled units, included in other liabilities on the Consolidated Balance Sheet, was $14 million (2013: $6 million).

EARNINGS_PER_COMMON_SHARE

EARNINGS PER COMMON SHARE	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
EARNINGS PER COMMON SHARE [Text Block]	'
	The following table sets forth the comparison of basic and diluted earnings per common share:
			Three months ended September 30,					Nine months ended September 30,
			2014			2013		2014			2013
		Basic earnings per common share
		Net income	$	282,966		$	150,635	$	633,693		$	545,916
		Less: noncontrolling interests	(6,160		)	—		(3,365		)	—
		Less: preferred shares dividends	10,022			13,514		30,066			30,452
		Less: loss on repurchase of preferred shares	—			—		—			3,081
		Net income available to common shareholders	279,104			137,121		606,992			512,383
		Weighted average common shares outstanding - basic	102,945			111,676		105,683			114,606
		Basic earnings per common share	$	2.71		$	1.23	$	5.74		$	4.47
		Diluted earnings per common share
		Net income available to common shareholders	$	279,104		$	137,121	$	606,992		$	512,383
		Weighted average common shares outstanding - basic	102,945			111,676		105,683			114,606
		Stock compensation plans	1,302			1,679		1,270			1,608
		Weighted average common shares outstanding - diluted	104,247			113,355		106,953			116,214
		Diluted earnings per common share	$	2.68		$	1.21	$	5.68		$	4.41
		Anti-dilutive shares excluded from the dilutive computation	3			54		376			334

SHAREHOLDERS_EQUITY

SHAREHOLDERS' EQUITY	9 Months Ended
	Sep. 30, 2014
Stockholders' Equity Note [Abstract]	'
SHAREHOLDERS' EQUITY [Text Block]	'
	The following table presents our common shares issued and outstanding:
			Three months ended September 30,					Nine months ended September 30,
			2014		2013			2014			2013
		Shares issued, balance at beginning of period	175,315		173,906			174,134			171,867
		Shares issued	84		71			1,265			2,110
		Total shares issued at end of period	175,399		173,977			175,399			173,977
		Treasury shares, balance at beginning of period	(71,409	)	(62,318	)		(64,649	)		(53,947	)
		Shares repurchased	(3,169	)	(11	)		(10,263	)		(8,502	)
		Shares reissued from treasury	6		3			340			123
		Total treasury shares at end of period	(74,572	)	(62,326	)		(74,572	)		(62,326	)
		Total shares outstanding	100,827		111,651			100,827			111,651
	Treasury Shares
	The following table presents our share repurchases:
			Three months ended September 30,							Nine months ended September 30,
			2014			2013				2014			2013
		In the open market:
		Total shares	3,159			—				9,838			5,048
		Total cost	$	150,000		$	—			$	450,000		$	225,000
		Average price per share(1)	$	47.49		$	—			$	45.74		$	44.57
		From employees:
		Total shares	10			11				425			454
		Total cost	$	449		$	489			$	18,532		$	18,413
		Average price per share(1)	$	45.39		$	44.12			$	43.65		$	40.56
		From founding shareholder:(2)
		Total shares	—			—				—			3,000
		Total cost	$	—		$	—			$	—		$	116,100
		Average price per share(1)	$	—		$	—			$	—		$	38.7
		Total shares repurchased:
		Total shares	3,169			11				10,263			8,502
		Total cost	$	150,449		$	489			$	468,532		$	359,513
		Average price per share(1)	$	47.48		$	44.12			$	45.65		$	42.29
	-1	Calculated using whole figures.
	(2) During the first quarter of 2013, we privately negotiated the repurchase of 3,000,000 common shares held by Trident II, L.P. and affiliated entities.

NONCONTROLLING_INTEREST

NONCONTROLLING INTEREST	9 Months Ended
	Sep. 30, 2014
Noncontrolling Interest [Abstract]	'
Noncontrolling Interest Disclosure [Text Block]	'
	During November 2013, the Company formed AXIS Ventures Reinsurance Limited (Ventures Re), a Bermuda domiciled insurer. Ventures Re was formed to write reinsurance on a fully collateralized basis.
	Following the formation of Ventures Re, third party investors purchased $50 million of Class A non-voting redeemable preferred share capital issued by this entity. The Ventures Re Class A preferred shares are redeemable at the sole discretion of Ventures Re's Board of Directors. During the third quarter of 2014, $10 million was returned to the Ventures Re Class A preferred share capital holders as part of a reduction of Ventures Re's share premium account.
	During the third quarter of 2014, third party investors purchased $25 million of Class B non-voting redeemable preferred share capital issued by Ventures Re. The Venture Re Class B preferred shares are redeemable at the sole discretion of Ventures Re's Board of Directors.
	Ventures Re is considered to be a variable interest entity. The Company has concluded that it is the primary beneficiary of Ventures Re as it has the power to direct, and has more than an insignificant economic interest in, the activities of this entity. Following this determination, Ventures Re was consolidated by the Company. Shareholders' equity attributable to Ventures Re's third party investors is recorded in the Consolidated Financial Statements as noncontrolling interests.
	At September 30, 2014, total assets of Ventures Re were $103 million (2013: $50 million), consisting primarily of cash and cash equivalents and insurance receivables. Total liabilities were $41 million (2013: $nil) consisting primarily of loss reserves and unearned premium. The assets of Ventures Re can only be used to settle its own liabilities, and there is no recourse to the Company for any liabilities incurred by this entity.
	The reconciliation of the beginning and ending balance of the noncontrolling interests in Ventures Re for the nine months ended September 30, 2014 was as follows:
			Total
			2014
		Balance at January 1, 2014	$	50,000
		Increase from issuance of preferred equity to noncontrolling interests	25,000
		Decrease from return of capital to noncontrolling interests	(10,000		)
		Amounts attributable to (from) noncontrolling interests	(3,365		)
		Balance at September 30, 2014	$	61,635

DEBT_AND_FINANCING_ARRANGEMENT

DEBT AND FINANCING ARRANGEMENTS	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
DEBT AND FINANCING ARRANGEMENTS [Text Block]	'
	a)	Senior Notes
	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") 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 and senior and rank equally with all other senior obligations of AXIS Capital. Net proceeds from this offering are expected to be used towards the repayment of $500 million of AXIS Capital’s 5.75% senior unsecured notes which mature on December 1, 2014.
	We have the option to redeem the 2.65% Senior Notes and the 5.15% 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. We were in compliance with all the covenants contained in the indentures at September 30, 2014.
	Interest expense recognized in relation to all of our senior unsecured 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 underlying senior notes are outstanding. During the three months ended September 30, 2014, we incurred interest expense of $20 million (2013: $15 million) and for the nine months ended September 30, 2014 we incurred $55 million (2013: $44 million), relating to all of our senior unsecured notes.
	b)	Credit Facilities
	Effective February 10, 2014, AXIS Specialty Finance PLC was added as a guarantor to our $250 million credit facility (the "Credit Facility").
	On March 31, 2014, AXIS Capital's subsidiary, AXIS Specialty Limited, terminated the $170 million secured letter of credit facility (the "Lloyd's LOC Facility") with ING Bank N.V., London Branch ("ING"). The Funds at Lloyd's requirements for the Company's subsidiary, AXIS Corporate Capital UK Limited, to support the underwriting capacity of the Company's Lloyd's syndicate, AXIS Syndicate 1686, are now being met by capital pledged in the form of fixed income securities deposited directly with Lloyd's.
	We are party to a $750 million letter of credit facility (the "LOC Facility") in addition to the Credit Facility. At September 30, 2014, letters of credit outstanding under the the LOC Facility and the Credit Facility totaled $429 million and $nil, respectively. There was no debt outstanding under the Credit Facility.
	We were in compliance with all LOC Facility and Credit Facility covenants at September 30, 2014.

COMMITMENTS_AND_CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
COMMITMENTS AND CONTINGENCIES [Text Block]	'
	We purchase reinsurance coverage for our insurance lines of business. The minimum reinsurance premiums are contractually due in advance on a quarterly basis. Actual payments under the reinsurance contracts will depend on the underlying subject premium and may exceed the minimum premium. In addition, we have entered into a reinsurance agreement that covers both our insurance and reinsurance segments for a period longer than one year. At September 30, 2014, we have outstanding reinsurance purchase commitments of $93 million relating to these annual and multi-year agreements.
	Refer 'Note 3 - Investments' for information on commitments related to our investment portfolio.

OTHER_COMPREHENSIVE_INCOME_LOS

OTHER COMPREHENSIVE INCOME (LOSS)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
OTHER COMPREHENSIVE INCOME (LOSS) [Text Block]	'
	The tax effects allocated to each component of other comprehensive income (loss) were as follows:
			2014												2013
			Before Tax Amount				Tax (Expense) Benefit				Net of Tax Amount				Before Tax Amount				Tax (Expense) Benefit			Net of Tax Amount
		Three months ended September 30,
		Available for sale investments:
		Unrealized gains (losses) arising during the period	$	(176,278	)		$	9,218			$	(167,060	)		$	118,821			$	(8,181	)	$	110,640
		Adjustment for reclassification of net realized investment gains and OTTI losses recognized in net income	(74,306		)		1,636				(72,670		)		(8,215		)		(442		)	(8,657		)
		Unrealized gains (losses) arising during the period, net of reclassification adjustment	(250,584		)		10,854				(239,730		)		110,606				(8,623		)	101,983
		Non-credit portion of OTTI losses	—				—				—				—				—			—
		Foreign currency translation adjustment	(10,000		)		—				(10,000		)		3,635				—			3,635
		Total other comprehensive income (loss), net of tax	$	(260,584	)		$	10,854			$	(249,730	)		$	114,241			$	(8,623	)	$	105,618
		Nine months ended September 30,
		Available for sale investments:
		Unrealized gains (losses) arising during the period	$	37,858			$	(12,984	)		$	24,874			$	(188,808	)		$	18,022		$	(170,786	)
		Adjustment for reclassification of net realized investment gains and OTTI losses recognized in net income	(130,634		)		14,421				(116,213		)		(51,166		)		4,595			(46,571		)
		Unrealized losses arising during the period, net of reclassification adjustment	(92,776		)		1,437				(91,339		)		(239,974		)		22,617			(217,357		)
		Non-credit portion of OTTI losses	—				—				—				—				—			—
		Foreign currency translation adjustment	(3,551		)		—				(3,551		)		(14,892		)		—			(14,892		)
		Total other comprehensive loss, net of tax	$	(96,327	)		$	1,437			$	(94,890	)		$	(254,866	)		$	22,617		$	(232,249	)
	Reclassifications out of AOCI into net income available to common shareholders were as follows:
				Amount Reclassified from AOCI(1)
		Details About AOCI Components	Consolidated Statement of Operations Line Item That Includes Reclassification	Three months ended September 30,								Nine months ended September 30,
				2014				2013				2014				2013
		Unrealized appreciation on available for sale investments
			Other realized investment gains (losses)	$	83,737			$	11,026			$	142,755			$	60,002
			OTTI losses	(9,431		)		(2,811		)		(12,121		)		(8,836		)
			Total before tax	74,306				8,215				130,634				51,166
			Income tax expense (benefit)	(1,636		)		442				(14,421		)		(4,595		)
			Net of tax	$	72,670			$	8,657			$	116,213			$	46,571
	-1	Amounts in parentheses are debits to net income available to common shareholders.

BASIS_OF_PRESENTATION_AND_ACCO1

BASIS OF PRESENTATION AND ACCOUNTING POLICIES (POLICIES)	9 Months Ended
	Sep. 30, 2014
Policy Text Block [Abstract]	'
Basis of Presentation [Policy Text Block]	'
	These interim consolidated financial statements include the accounts of AXIS Capital Holdings Limited (“AXIS Capital”) and its subsidiaries (herein referred to as “we,” “us,” “our,” or the “Company”).
	The consolidated balance sheet at September 30, 2014 and the consolidated statements of operations, comprehensive income, shareholders' equity and cash flows for the periods ended September 30, 2014 and 2013 have not been audited. The balance sheet at December 31, 2013 is derived from our audited financial statements.
	These financial statements have been prepared in accordance with U.S. Generally Accepted Accounting Principles (“U.S. GAAP”) for interim financial information and with the Securities and Exchange Commission's (“SEC”) instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, these financial statements reflect all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of our financial position and results of operations for the periods presented. The results of operations for any interim period are not necessarily indicative of the results for a full year. All inter-company accounts and transactions have been eliminated.
	The following information should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2013. Tabular dollar and share amounts are in thousands, except per share amounts. All amounts are reported in U.S. dollars.
	Significant Accounting Policies
	There were no notable changes in our significant accounting policies subsequent to our Annual Report on Form 10-K for the year ended December 31, 2013
Recently Issued Accounting Standards Not Yet Adopted [Policy Text Block]	'
	Recently Issued Accounting Standards Not Yet Adopted
	Share-Based Compensation
	In June 2014, the Financial Accounting Standards Board ("FASB") issued new guidance for share-based payments where a performance target could be achieved after the requisite service period has ended, requiring that compensation costs be recognized in the period in which it becomes probable that the performance target will be achieved and to represent the compensation cost attributable to the period(s) for which the requisite service has already been rendered. This guidance is effective for reporting periods beginning after December 15, 2015, with early adoption permitted. As the new guidance was issued to clarify treatment where there was divergence in accounting practice, the adoption of this guidance is not expected to impact our results of operations, financial condition or liquidity.

SEGMENT_INFORMATION_TABLES

SEGMENT INFORMATION (TABLES)	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
UNDERWRITING RESULTS OF REPORTABLE SEGMENTS [Table Text Block]	'
			2014									2013
		Three months ended and at September 30,	Insurance			Reinsurance			Total			Insurance			Reinsurance			Total
		Gross premiums written	$	555,283		$	341,531		$	896,814		$	574,778		$	330,019		$	904,797
		Net premiums written	363,571			323,652			687,223			393,627			322,762			716,389
		Net premiums earned	461,805			504,333			966,138			448,072			497,170			945,242
		Other insurance related income	—			7,702			7,702			725			—			725
		Net losses and loss expenses	(289,207		)	(262,857		)	(552,064		)	(216,440		)	(285,082		)	(501,522		)
		Acquisition costs	(71,264		)	(114,686		)	(185,950		)	(61,087		)	(112,595		)	(173,682		)
		General and administrative expenses	(85,750		)	(36,612		)	(122,362		)	(82,548		)	(35,127		)	(117,675		)
		Underwriting income	$	15,584		$	97,880		113,464			$	88,722		$	64,366		153,088
		Corporate expenses							(30,554		)							(23,024		)
		Net investment income							66,562									103,429
		Net realized investment gains (losses)							77,448									(4,708		)
		Foreign exchange (losses) gains							72,292									(56,860		)
		Interest expense and financing costs							(20,344		)							(15,260		)
		Income before income taxes							$	278,868								$	156,665
		Net loss and loss expense ratio	62.6		%	52.1		%	57.1		%	48.3		%	57.3		%	53.1		%
		Acquisition cost ratio	15.4		%	22.7		%	19.2		%	13.6		%	22.6		%	18.4		%
		General and administrative expense ratio	18.6		%	7.3		%	15.9		%	18.5		%	7.2		%	14.8		%
		Combined ratio	96.6		%	82.1		%	92.2		%	80.4		%	87.1		%	86.3		%
		Goodwill and intangible assets	$	88,740		$	—		$	88,740		$	91,656		$	—		$	91,656
			2014									2013
		Nine months ended and at September 30,	Insurance			Reinsurance			Total			Insurance			Reinsurance			Total
		Gross premiums written	$	1,911,102		$	2,038,377		$	3,949,479		$	1,952,548		$	1,918,537		$	3,871,085
		Net premiums written	1,361,351			1,990,607			3,351,958			1,385,892			1,894,344			3,280,236
		Net premiums earned	1,368,683			1,543,799			2,912,482			1,272,297			1,492,857			2,765,154
		Other insurance related income	—			12,468			12,468			1,756			—			1,756
		Net losses and loss expenses	(859,093		)	(803,004		)	(1,662,097		)	(764,768		)	(818,067		)	(1,582,835		)
		Acquisition costs	(207,360		)	(342,488		)	(549,848		)	(177,097		)	(311,795		)	(488,892		)
		General and administrative expenses	(257,208		)	(106,987		)	(364,195		)	(257,962		)	(103,411		)	(361,373		)
		Underwriting income	$	45,022		$	303,788		348,810			$	74,226		$	259,584		333,810
		Corporate expenses							(92,530		)							(69,834		)
		Net investment income							264,171									295,450
		Net realized investment gains							121,329									56,004
		Foreign exchange (losses) gains							58,353									(11,659		)
		Interest expense and financing costs							(56,913		)							(46,355		)
		Income before income taxes							$	643,220								$	557,416
		Net loss and loss expense ratio	62.8		%	52		%	57.1		%	60.1		%	54.8		%	57.2		%
		Acquisition cost ratio	15.2		%	22.2		%	18.9		%	13.9		%	20.9		%	17.7		%
		General and administrative expense ratio	18.7		%	6.9		%	15.6		%	20.3		%	6.9		%	15.6		%
		Combined ratio	96.7		%	81.1		%	91.6		%	94.3		%	82.6		%	90.5		%
		Goodwill and intangible assets	$	88,740		$	—		$	88,740		$	91,656		$	—		$	91,656

INVESTMENTS_TABLES

INVESTMENTS (TABLES)	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
AMORTIZED COST/COST AND FAIR VALUES OF FIXED MATURITIES AND EQUITIES [Table Text Block]	'
			Amortized			Gross				Gross			Fair			Non-credit
			Cost or			Unrealized				Unrealized			Value			OTTI
			Cost			Gains				Losses						in AOCI(5)
		At September 30, 2014
		Fixed maturities
		U.S. government and agency	$	1,545,328		$	1,564			$	(27,424	)	$	1,519,468		$	—
		Non-U.S. government	1,175,260			9,122				(45,460		)	1,138,922			—
		Corporate debt	4,240,910			47,065				(37,179		)	4,250,796			—
		Agency RMBS(1)	2,103,587			28,931				(11,571		)	2,120,947			—
		CMBS(2)	945,134			12,212				(2,829		)	954,517			—
		Non-Agency RMBS	75,452			3,531				(588		)	78,395			(888		)
		ABS(3)	1,443,932			3,775				(11,842		)	1,435,865			—
		Municipals(4)	910,669			36,181				(1,076		)	945,774			—
		Total fixed maturities	$	12,440,272		$	142,381			$	(137,969	)	$	12,444,684		$	(888	)
		Equity securities
		Common stocks	$	49,426		$	14,367			$	(648	)	$	63,145
		Exchange-traded funds	420,219			31,506				(1,049		)	450,676
		Non-U.S. bond mutual funds	113,651			2,030				—			115,681
		Total equity securities	$	583,296		$	47,903			$	(1,697	)	$	629,502
		At December 31, 2013
		Fixed maturities
		U.S. government and agency	$	1,421,245		$	1,405			$	(33,952	)	$	1,388,698		$	—
		Non-U.S. government	1,208,384			17,990				(49,992		)	1,176,382			—
		Corporate debt	3,533,585			84,881				(10,228		)	3,608,238			—
		Agency RMBS(1)	2,485,139			21,979				(58,291		)	2,448,827			—
		CMBS(2)	790,095			11,285				(3,966		)	797,414			—
		Non-Agency RMBS	65,590			2,375				(398		)	67,567			(868		)
		ABS(3)	955,274			6,871				(8,694		)	953,451			—
		Municipals(4)	1,527,834			32,432				(14,516		)	1,545,750			—
		Total fixed maturities	$	11,987,146		$	179,218			$	(180,037	)	$	11,986,327		$	(868	)
		Equity securities
		Common stocks	$	345,759		$	98,742			$	(6,183	)	$	438,318
		Exchange-traded funds	106,762			32,085				—			138,847
		Non-U.S. bond mutual funds	113,698			11,124				—			124,822
		Total equity securities	$	566,219		$	141,951			$	(6,183	)	$	701,987
	-1	Residential mortgage-backed securities (RMBS) originated by U.S. agencies.
	-2	Commercial mortgage-backed securities (CMBS).
	-3	Asset-backed securities (ABS) include debt tranched securities collateralized primarily by auto loans, student loans, credit cards, and other asset types. This asset class also includes collateralized loan obligations (CLOs) and collateralized debt obligations (CDOs).
	-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 of securities. It does not include the change in fair value subsequent to the impairment measurement date.
CONTRACTUAL MATURITIES OF FIXED MATURITIES [Table Text Block]	'
			Amortized			Fair				% of Total
			Cost			Value				Fair Value
		At September 30, 2014
		Maturity
		Due in one year or less	$	550,351		$	549,150			4.5	%
		Due after one year through five years	5,250,453			5,266,397				42.3	%
		Due after five years through ten years	1,822,740			1,788,151				14.4	%
		Due after ten years	248,623			251,262				2	%
			7,872,167			7,854,960				63.2	%
		Agency RMBS	2,103,587			2,120,947				17	%
		CMBS	945,134			954,517				7.7	%
		Non-Agency RMBS	75,452			78,395				0.6	%
		ABS	1,443,932			1,435,865				11.5	%
		Total	$	12,440,272		$	12,444,684			100	%
		At December 31, 2013
		Maturity
		Due in one year or less	$	710,079		$	717,052			5.9	%
		Due after one year through five years	5,030,728			5,116,060				42.7	%
		Due after five years through ten years	1,852,877			1,791,835				14.9	%
		Due after ten years	97,364			94,121				0.8	%
			7,691,048			7,719,068				64.3	%
		Agency RMBS	2,485,139			2,448,827				20.4	%
		CMBS	790,095			797,414				6.7	%
		Non-Agency RMBS	65,590			67,567				0.6	%
		ABS	955,274			953,451				8	%
		Total	$	11,987,146		$	11,986,327			100	%
FIXED MATURITIES AND EQUITIES IN AN UNREALIZED LOSS POSITION [Table Text Block]	'
			12 months or greater							Less than 12 months						Total
			Fair			Unrealized				Fair			Unrealized			Fair			Unrealized
			Value			Losses				Value			Losses			Value			Losses
		At September 30, 2014
		Fixed maturities
		U.S. government and agency	$	392,084		$	(23,150	)		$	864,003		$	(4,274	)	$	1,256,087		$	(27,424	)
		Non-U.S. government	148,526			(25,903		)		395,307			(19,557		)	543,833			(45,460		)
		Corporate debt	35,841			(2,608		)		2,006,740			(34,571		)	2,042,581			(37,179		)
		Agency RMBS	335,687			(9,617		)		469,445			(1,954		)	805,132			(11,571		)
		CMBS	77,827			(1,066		)		310,078			(1,763		)	387,905			(2,829		)
		Non-Agency RMBS	8,217			(524		)		3,087			(64		)	11,304			(588		)
		ABS	378,668			(8,122		)		640,305			(3,720		)	1,018,973			(11,842		)
		Municipals	39,450			(1,047		)		8,226			(29		)	47,676			(1,076		)
		Total fixed maturities	$	1,416,300		$	(72,037	)		$	4,697,191		$	(65,932	)	$	6,113,491		$	(137,969	)
		Equity securities
		Common stocks	$	1,828		$	(249	)		$	10,401		$	(399	)	$	12,229		$	(648	)
		Exchange-traded funds	—			—				56,074			(1,049		)	56,074			(1,049		)
		Total equity securities	$	1,828		$	(249	)		$	66,475		$	(1,448	)	$	68,303		$	(1,697	)
		At December 31, 2013
		Fixed maturities
		U.S. government and agency	$	—		$	—			$	982,307		$	(33,952	)	$	982,307		$	(33,952	)
		Non-U.S. government	35,577			(3,430		)		420,622			(46,562		)	456,199			(49,992		)
		Corporate debt	27,696			(802		)		606,592			(9,426		)	634,288			(10,228		)
		Agency RMBS	144,468			(5,247		)		1,478,527			(53,044		)	1,622,995			(58,291		)
		CMBS	13,319			(116		)		298,863			(3,850		)	312,182			(3,966		)
		Non-Agency RMBS	4,287			(315		)		5,319			(83		)	9,606			(398		)
		ABS	37,765			(2,941		)		553,803			(5,753		)	591,568			(8,694		)
		Municipals	8,408			(615		)		543,474			(13,901		)	551,882			(14,516		)
		Total fixed maturities	$	271,520		$	(13,466	)		$	4,889,507		$	(166,571	)	$	5,161,027		$	(180,037	)
		Equity securities
		Common stocks	$	3,499		$	(398	)		$	48,828		$	(5,785	)	$	52,327		$	(6,183	)
		Exchange-traded funds	—			—				—			—			—			—
		Total equity securities	$	3,499		$	(398	)		$	48,828		$	(5,785	)	$	52,327		$	(6,183	)
PORTFOLIO OF OTHER INVESTMENTS [Table Text Block]	'
			Fair Value						Redemption Frequency		Redemption
									(if currently eligible)		Notice Period
		At September 30, 2014
		Long/short equity funds	$	292,086		31	%		Quarterly, Semi-annually		45-60 days
		Multi-strategy funds	315,480			33	%		Quarterly, Semi-annually		60-95 days
		Event-driven funds	188,397			20	%		Quarterly, Annually		45-60 days
		Leveraged bank loan funds	9,904			1	%		Quarterly		65 days
		Direct lending funds	43,836			5	%		n/a		n/a
		CLO - Equities	97,133			10	%		n/a		n/a
		Total other investments	$	946,836		100	%
		At December 31, 2013
		Long/short equity funds	$	425,444		41	%		Monthly, Quarterly, Semi-annually		30-60 days
		Multi-strategy funds	285,155			27	%		Quarterly, Semi-annually		60-95 days
		Event-driven funds	190,458			18	%		Quarterly, Annually		45-60 days
		Leveraged bank loan funds	48,753			5	%		Quarterly		65 days
		Direct lending funds	22,134			2	%		n/a		n/a
		CLO - Equities	73,866			7	%		n/a		n/a
		Total other investments	$	1,045,810		100	%
	n/a - not applicable
NET INVESTMENT INCOME [Table Text Block]	'
			Three months ended September 30,							Nine months ended September 30,
			2014			2013				2014			2013
		Fixed maturities	$	74,996		$	74,691			$	226,475		$	218,877
		Other investments	(3,384		)	32,127				45,868			87,406
		Equity securities	2,022			3,871				9,609			8,419
		Cash and cash equivalents	2,081			382				9,127			2,915
		Short-term investments	141			127				600			1,056
		Gross investment income	75,856			111,198				291,679			318,673
		Investment expenses	(9,294		)	(7,769		)		(27,508		)	(23,223		)
		Net investment income	$	66,562		$	103,429			$	264,171		$	295,450
NET REALIZED INVESTMENT GAINS [Table Text Block]	'
			Three months ended September 30,							Nine months ended September 30,
			2014			2013				2014			2013
		Gross realized gains
		Fixed maturities and short-term investments	$	17,638		$	27,631			$	78,057		$	94,617
		Equities	81,888			11,985				133,764			48,266
		Gross realized gains	99,526			39,616				211,821			142,883
		Gross realized losses
		Fixed maturities and short-term investments	(8,527		)	(26,454		)		(56,623		)	(73,266		)
		Equities	(7,120		)	(2,001		)		(12,104		)	(9,011		)
		Gross realized losses	(15,647		)	(28,455		)		(68,727		)	(82,277		)
		Net OTTI recognized in earnings	(9,431		)	(2,811		)		(12,121		)	(8,836		)
		Change in fair value of investment derivatives(1)	3,000			(13,058		)		(9,644		)	4,234
		Net realized investment gains (losses)	$	77,448		$	(4,708	)		$	121,329		$	56,004
	(1) Refer to Note 5 – Derivative Instruments
OTTI RECOGNIZED IN EARNINGS BY ASSET CLASS [Table Text Block]	'
			Three months ended September 30,							Nine months ended September 30,
			2014			2013				2014			2013
		Fixed maturities:
		Non-U.S. government	$	3,380		$	94			$	5,192		$	120
		Corporate debt	1,031			1,811				1,112			5,761
		Non-Agency RMBS	—			57				—			57
		ABS	—			—				56			129
		Municipals	418			639				418			639
			4,829			2,601				6,778			6,706
		Equity Securities
		Common stocks	—			207				741			1,607
		Exchange-traded funds	4,602			3				4,602			523
			4,602			210				5,343			2,130
		Total OTTI recognized in earnings	$	9,431		$	2,811			$	12,121		$	8,836
ROLL FORWARD OF CREDIT LOSSES FOR WHICH A PORTION OF OTTI RECOGNIZED IN AOCI [Table Text Block]	'
			Three months ended September 30,							Nine months ended September 30,
			2014			2013				2014			2013
		Balance at beginning of period	$	1,581		$	1,699			$	1,594		$	1,809
		Credit impairments recognized on securities not previously impaired	—			—				—			—
		Additional credit impairments recognized on securities previously impaired	—			—				—			—
		Change in timing of future cash flows on securities previously impaired	—			—				—			—
		Intent to sell of securities previously impaired	—			—				—			—
		Securities sold/redeemed/matured	(23		)	(110		)		(36		)	(220		)
		Balance at end of period	$	1,558		$	1,589			$	1,558		$	1,589

FAIR_VALUE_MEASUREMENTS_TABLES

FAIR VALUE MEASUREMENTS (TABLES)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
FINANCIAL INSTRUMENTS MEASURED AT FAIR VALUE ON A RECURRING BASIS [Table Text Block]	'
			Quoted Prices in				Significant			Significant			Total Fair
			Active Markets for				Other Observable			Unobservable			Value
			Identical Assets				Inputs			Inputs
			(Level 1)				(Level 2)			(Level 3)
		At September 30, 2014
		Assets
		Fixed maturities
		U.S. government and agency	$	1,390,737			$	128,731		$	—		$	1,519,468
		Non-U.S. government	—				1,138,922			—			1,138,922
		Corporate debt	—				4,250,796			—			4,250,796
		Agency RMBS	—				2,120,947			—			2,120,947
		CMBS	—				939,897			14,620			954,517
		Non-Agency RMBS	—				78,395			—			78,395
		ABS	—				1,375,330			60,535			1,435,865
		Municipals	—				945,774			—			945,774
			1,390,737				10,978,792			75,155			12,444,684
		Equity securities
		Common stocks	63,145				—			—			63,145
		Exchange-traded funds	450,676				—			—			450,676
		Non-U.S. bond mutual funds	—				115,681			—			115,681
			513,821				115,681			—			629,502
		Other investments
		Hedge funds	—				361,376			444,491			805,867
		Direct lending funds	—				—			43,836			43,836
		CLO - Equities	—				—			97,133			97,133
			—				361,376			585,460			946,836
		Short-term investments	—				114,428			—			114,428
		Derivative instruments (see Note 5)	—				16,591			228			16,819
		Total Assets	$	1,904,558			$	11,586,868		$	660,843		$	14,152,269
		Liabilities
		Derivative instruments (see Note 5)	$	—			$	10,469		$	7,646		$	18,115
		Cash settled awards (see Note 7)	—				14,106			—			14,106
		Total Liabilities	$	—			$	24,575		$	7,646		$	32,221
		At December 31, 2013
		Assets
		Fixed maturities
		U.S. government and agency	$	1,119,632			$	269,066		$	—		$	1,388,698
		Non-U.S. government	—				1,176,382			—			1,176,382
		Corporate debt	—				3,608,238			—			3,608,238
		Agency RMBS	—				2,448,827			—			2,448,827
		CMBS	—				793,396			4,018			797,414
		Non-Agency RMBS	—				67,567			—			67,567
		ABS	—				922,652			30,799			953,451
		Municipals	—				1,545,750			—			1,545,750
			1,119,632				10,831,878			34,817			11,986,327
		Equity securities
		Common stocks	438,318				—			—			438,318
		Exchange-traded funds	138,847				—			—			138,847
		Non-U.S. bond mutual funds	—				124,822			—			124,822
			577,165				124,822			—			701,987
		Other investments
		Hedge funds	—				488,755			461,055			949,810
		Direct lending funds	—				—			22,134			22,134
		CLO - Equities	—				—			73,866			73,866
			—				488,755			557,055			1,045,810
		Short-term investments	—				46,212			—			46,212
		Derivative instruments (see Note 5)	—				6,824			984			7,808
		Total Assets	$	1,696,797			$	11,498,491		$	592,856		$	13,788,144
		Liabilities
		Derivative instruments (see Note 5)	$	—			$	1,152		$	815		$	1,967
		Cash settled awards (see Note 7)	—				8,693			—			8,693
		Total Liabilities	$	—			$	9,845		$	815		$	10,660
LEVEL 3 FAIR VALUE MEASUREMENT INPUTS [Table Text Block]	'
			Fair Value			Valuation Technique	Unobservable Input	Range	Weighted
									Average
		ABS - CLO Debt	$	17,810		Discounted cash flow	Credit spreads	3.40%	3.40%
							Illiquidity discount (1)	5.00%	5.00%
			42,725			Broker-dealer quote	n/a	n/a	n/a
			$	60,535
		Other investments - CLO - Equities	$	37,420		Discounted cash flow	Default rates	4.0% - 5.0%	4.30%
							Loss severity rate	53.50%	53.50%
							Collateral spreads	2.6% - 3.5%	3.30%
							Estimated maturity dates	3.2 - 4.4 years	3.9 years
			59,713			Net asset value	n/a	n/a	n/a
			$	97,133
		Derivatives - Weather derivatives, net	$	(7,418	)	Simulation model	Weather curve	33 - 2930(2)	n/a (3)
							Weather standard deviation	3 - 305(2)	n/a (3)
	(1) Judgmentally determined based on limited trades of similar securities observed in the secondary markets.
	(2) Measured in Heating Degree Days ("HDD") which is the number of degrees the daily temperature is below a reference temperature. The cumulative HDD for the duration of the derivatives contract is compared to the strike value to determine the necessary settlement.
	-3	Due to the diversity of the portfolio, the range of unobservable inputs can be widespread; therefore, presentation of a weighted average is not useful. Weather parameters may include various temperature and/or precipitation measures that will naturally vary by geographic location of each counterparty's operations.
CHANGES IN LEVEL 3 FINANCIAL INSTRUMENTS MEASURED AT FAIR VALUE ON A RECURRING BASIS [Table Text Block]	'
			Opening				Transfers			Transfers			Included in			Included			Purchases		Sales			Settlements/			Closing		Change in
			Balance				into			out of			earnings (1)			in OCI (2)								Distributions			Balance		unrealized
							Level 3			Level 3																			investment
																													gain/(loss) (3)
		Three months ended September 30, 2014
		Fixed maturities
		Corporate debt	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
		Non-Agency RMBS	—				—			—			—			—			—		—			—			—		—
		CMBS	3,933				10,795			—			—			(31		)	—		—			(77		)	14,620		—
		ABS	30,883				42,039			—			—			882			—		—			(13,269		)	60,535		—
			34,816				52,834			—			—			851			—		—			(13,346		)	75,155		—
		Other investments
		Hedge funds	476,808				—			(32,255		)	(4,205		)	—			6,000		—			(1,857		)	444,491		(4,344		)
		Direct lending funds	33,467				—			—			627			—			10,086		—			(344		)	43,836		627
		CLO - Equities	91,106				—			—			5,729			—			6,674		—			(6,376		)	97,133		5,729
			601,381				—			(32,255		)	2,151			—			22,760		—			(8,577		)	585,460		2,012
		Other assets
		Derivative instruments	—				—			—			228			—			—		—			—			228		228
			—				—			—			228			—			—		—			—			228		228
		Total assets	$	636,197			$	52,834		$	(32,255	)	$	2,379		$	851		$	22,760	$	—		$	(21,923	)	$	660,843	$	2,240
		Other liabilities
		Derivative instruments	$	750			$	—		$	—		$	(272	)	$	—		$	7,587	$	—		$	(419	)	$	7,646	$	59
		Total liabilities	$	750			$	—		$	—		$	(272	)	$	—		$	7,587	$	—		$	(419	)	$	7,646	$	59
		Nine months ended September 30, 2014
		Fixed maturities
		Corporate debt	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
		Non-Agency RMBS	—				—			—			—			—			—		—			—			—		—
		CMBS	4,018				10,795			—			—			(74		)	—		—			(119		)	14,620		—
		ABS	30,799				42,167			—			—			1,060			—		—			(13,491		)	60,535		—
			34,817				52,962			—			—			986			—		—			(13,610		)	75,155		—
		Other investments
		Hedge funds	461,055				—			(32,255		)	16,718			—			13,500		—			(14,527		)	444,491		16,579
		Direct lending funds	22,134				—			—			1,546			—			20,831		—			(675		)	43,836		1,546
		CLO - Equities	73,866				—			—			17,060			—			25,941		—			(19,734		)	97,133		17,060
			557,055				—			(32,255		)	35,324			—			60,272		—			(34,936		)	585,460		35,185
		Other assets
		Derivative instruments	984				—			—			5,239			—			—		—			(5,995		)	228		228
			984				—			—			5,239			—			—		—			(5,995		)	228		228
		Total assets	$	592,856			$	52,962		$	(32,255	)	$	40,563		$	986		$	60,272	$	—		$	(54,541	)	$	660,843	$	35,413
		Other liabilities
		Derivative instruments	$	815			$	—		$	—		$	624		$	—		$	8,427	$	—		$	(2,220	)	$	7,646	$	59
		Total liabilities	$	815			$	—		$	—		$	624		$	—		$	8,427	$	—		$	(2,220	)	$	7,646	$	59
	-1	Gains and losses included in earnings on fixed maturities are included in net realized investment gains (losses). Gains and (losses) included in earnings on other investments are included in net investment income. Gains (losses) on weather derivatives included in earnings are included in other insurance-related income.
	-2	Gains and losses included in other comprehensive income (“OCI”) on fixed maturities are included in unrealized gains (losses) arising during the period.
	-3	Change in unrealized investment gain (loss) relating to assets held at the reporting date.
			Opening				Transfers			Transfers			Included in			Included			Purchases		Sales			Settlements/			Closing		Change in
			Balance				into			out of			earnings (1)			in OCI (2)								Distributions			Balance		unrealized
							Level 3			Level 3																			investment
																													gain/(loss)  (3)
		Three months ended September 30, 2013
		Fixed maturities
		Corporate debt	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
		Non-Agency RMBS	—				—			—			—			—			—		—			—			—		—
		CMBS	11,785				—			(6,915		)	—			(96		)	—		—			(714		)	4,060		—
		ABS	54,125				34,700			—			—			1,048			—		—			(20,368		)	69,505		—
			65,910				34,700			(6,915		)	—			952			—		—			(21,082		)	73,565		—
		Other investments
		Hedge funds	444,220				—			—			13,233			—			—		—			(19,156		)	438,297		13,233
		Direct lending funds	4,232				—			—			75			—			8,708		—			—			13,015		75
		CLO - Equities	53,044				—			—			6,580			—			23,312		—			(12,736		)	70,200		6,580
			501,496				—			—			19,888			—			32,020		—			(31,892		)	521,512		19,888
		Other assets
		Derivative instruments	—				—			—			—			—			—		—			—			—		—
		—				—			—			—			—			—		—			—			—		—
	Total assets	$	567,406			$	34,700		$	(6,915	)	$	19,888		$	952		$	32,020	$	—		$	(52,974	)	$	595,077	$	19,888
	Other liabilities
	Derivative instruments	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
	Total liabilities	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
	Nine months ended September 30, 2013
	Fixed maturities
	Corporate debt	$	1,550			$	—		$	—		$	1,550		$	—		$	—	$	(3,100	)	$	—		$	—	$	—
	Non-Agency RMBS	1,110				—			(1,223		)	—			135			—		—			(22		)	—		—
	CMBS	4,296				8,382			(6,915		)	—			(243		)	—		—			(1,460		)	4,060		—
	ABS	63,975				34,700			(213,212		)	(112		)	2,029			212,889		(10,190		)	(20,574		)	69,505		—
		70,931				43,082			(221,350		)	1,438			1,921			212,889		(13,290		)	(22,056		)	73,565		—
	Other investments
	Hedge funds	359,996				29,953			—			38,723			—			50,000		—			(40,375		)	438,297		38,723
	Direct lending funds	—				—			—			75			—			12,940		—			—			13,015		75
	CLO - Equities	62,435				—			—			21,605			—			23,312		—			(37,152		)	70,200		21,605
		422,431				29,953			—			60,403			—			86,252		—			(77,527		)	521,512		60,403
	Other assets
	Derivative instruments	—				—			—			—			—			—		—			—			—		—
		—				—			—			—			—			—		—			—			—		—
	Total assets	$	493,362			$	73,035		$	(221,350	)	$	61,841		$	1,921		$	299,141	$	(13,290	)	$	(99,583	)	$	595,077	$	60,403
	Other liabilities
	Derivative instruments	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
	Total liabilities	$	—			$	—		$	—		$	—		$	—		$	—	$	—		$	—		$	—	$	—
-1	Gains and losses included in earnings on fixed maturities are included in net realized investment gains (losses). Gains and (losses) included in earnings on other investments are included in net investment income. Gains (losses) on weather derivatives included in earnings are included in other insurance-related income.
-2	Gains and losses included in other comprehensive income (“OCI”) on fixed maturities are included in unrealized gains (losses) arising during the period.
-3	Change in unrealized investment gain (loss) relating to assets held at the reporting date.

DERIVATIVE_INSTRUMENTS_TABLES

DERIVATIVE INSTRUMENTS (TABLES)	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
LOCATION AND AMOUNTS OF DERIVATIVE FAIR VALUES ON THE CONSOLIDATED BALANCE SHEET [Table Text Block]	'
			September 30, 2014												December 31, 2013
			Derivative				Derivative				Derivative				Derivative				Derivative		Derivative
			Notional				Asset				Liability				Notional				Asset		Liability
			Amount				Fair				Fair				Amount				Fair		Fair
							Value(1)				Value(1)								Value(1)		Value(1)
		Derivatives not designated as hedging instruments
		Relating to investment portfolio:
		Foreign exchange forward contracts	$	167,105			$	5,175			$	11			$	254,023			$	1,214	$	1,032
		Interest rate swaps	346,250				—				624				281,250				873		—
		Relating to underwriting portfolio:
		Foreign exchange forward contracts	616,539				316				9,834				390,663				4,737		120
		Weather-related contracts	53,017				228				7,646				24,451				984		815
		Commodity contracts	$	100,850			11,100				—				$	—			—		—
		Total derivatives					$	16,819			$	18,115							$	7,808	$	1,967
	-1	Asset and liability derivatives are classified within other assets and other liabilities in the Consolidated Balance Sheets.
RECONCILIATION OF GROSS DERIVATIVE ASSETS AND LIABILITIES TO NET AMOUNTS PRESENTED IN BALANCE SHEETS [Table Text Block]	'
			September 30, 2014										December 31, 2013
			Gross Amounts			Gross Amounts Offset			Net				Gross Amounts			Gross Amounts Offset			Net
									Amounts(1)										Amounts(1)
		Derivative assets	$	25,823		$	(9,004	)	$	16,819			$	9,796		$	(1,988	)	$	7,808
		Derivative liabilities	$	27,119		$	(9,004	)	$	18,115			$	3,955		$	(1,988	)	$	1,967
	-1	Net asset and liability derivatives are classified within other assets and other liabilities in the Consolidated Balance Sheets.
NET EARNINGS IMPACT OF FAIR VALUE HEDGES AND TOTAL UNREALIZED AND REALIZED GAINS (LOSSES) ON DERIVATIVES NOT DESIGNATED AS HEDGES RECORDED IN EARNINGS [Table Text Block]	'
			Location of Gain (Loss) Recognized in Income on Derivative	Three months ended September 30,								Nine months ended September 30,
				2014				2013				2014				2013
		Derivatives not designated as hedging instruments
		Relating to investment portfolio:
		Foreign exchange forward contracts	Net realized investment gains (losses)	$	7,034			$	(7,802	)		$	3,350			$	9,222
		Interest rate swaps	Net realized investment gains (losses)	(4,034		)		(5,256		)		(12,994		)		(4,988		)
		Relating to underwriting portfolio:
		Foreign exchange forward contracts	Foreign exchange losses (gains)	(21,915		)		(2,697		)		(8,784		)		(4,895		)
		Weather-related contracts	Other insurance related income	668				—				4,730				—
		Commodity contracts	Other insurance related income	7,530				—				9,243				—
		Total		$	(10,717	)		$	(15,755	)		$	(4,455	)		$	(661	)

RESERVE_FOR_LOSSES_AND_LOSS_EX1

RESERVE FOR LOSSES AND LOSS EXPENSES (TABLES)	9 Months Ended
	Sep. 30, 2014
Insurance Loss Reserves [Abstract]	'
RECONCILIATION OF BEGINNING AND ENDING GROSS RESERVE FOR LOSSES AND LOSS EXPENSES AND NET RESERVE FOR UNPAID LOSSES AND LOSS EXPENSES [Table Text Block]	'
		Nine months ended September 30,	2014			2013
		Gross reserve for losses and loss expenses, beginning of period	$	9,582,140		$	9,058,731
		Less reinsurance recoverable on unpaid losses, beginning of period	(1,900,112		)	(1,825,617		)
		Net reserve for unpaid losses and loss expenses, beginning of period	7,682,028			7,233,114
		Net incurred losses and loss expenses related to:
		Current year	1,855,482			1,759,483
		Prior years	(193,385		)	(176,648		)
			1,662,097			1,582,835
		Net paid losses and loss expenses related to:
		Current year	(202,364		)	(168,564		)
		Prior years	(1,165,215		)	(1,028,401		)
			(1,367,579		)	(1,196,965		)
		Foreign exchange and other	(139,313		)	(17,265		)
		Net reserve for unpaid losses and loss expenses, end of period	7,837,233			7,601,719
		Reinsurance recoverable on unpaid losses, end of period	1,914,670			1,882,797
		Gross reserve for losses and loss expenses, end of period	$	9,751,903		$	9,484,516
NET PRIOR YEAR RESERVE DEVELOPMENT BY SEGMENT [Table Text Block]	'
			Three months ended September 30,						Nine months ended September 30,
			2014			2013			2014		2013
		Insurance	$	9,488		$	34,065		$	54,059	$	46,355
		Reinsurance	55,050			45,970			139,326		130,293
		Total	$	64,538		$	80,035		$	193,385	$	176,648

SHAREBASED_COMPENSATION_TABLES

SHARE-BASED COMPENSATION (TABLES)	9 Months Ended
	Sep. 30, 2014
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 [Table Text Block]	'
			Performance-based Stock Awards			Service-based Stock Awards
			Number of	Weighted Average		Number of		Weighted Average
			Restricted	Grant Date		Restricted		Grant Date
			Stock	Fair Value		Stock		Fair Value
		Nonvested restricted stock - beginning of period	283	$	35.74	3,430		$	34.72
		Granted	68	44.33		1,038		44.42
		Vested	—	—		(1,440	)	33.82
		Forfeited	—	—		(193	)	36.77
		Nonvested restricted stock - end of period	351	$	37.41	2,835		$	38.54

EARNINGS_PER_COMMON_SHARE_TABL

EARNINGS PER COMMON SHARE (TABLES)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
BASIC AND DILUTED EARNINGS PER COMMON SHARE [Table Text Block]	'
			Three months ended September 30,					Nine months ended September 30,
			2014			2013		2014			2013
		Basic earnings per common share
		Net income	$	282,966		$	150,635	$	633,693		$	545,916
		Less: noncontrolling interests	(6,160		)	—		(3,365		)	—
		Less: preferred shares dividends	10,022			13,514		30,066			30,452
		Less: loss on repurchase of preferred shares	—			—		—			3,081
		Net income available to common shareholders	279,104			137,121		606,992			512,383
		Weighted average common shares outstanding - basic	102,945			111,676		105,683			114,606
		Basic earnings per common share	$	2.71		$	1.23	$	5.74		$	4.47
		Diluted earnings per common share
		Net income available to common shareholders	$	279,104		$	137,121	$	606,992		$	512,383
		Weighted average common shares outstanding - basic	102,945			111,676		105,683			114,606
		Stock compensation plans	1,302			1,679		1,270			1,608
		Weighted average common shares outstanding - diluted	104,247			113,355		106,953			116,214
		Diluted earnings per common share	$	2.68		$	1.21	$	5.68		$	4.41
		Anti-dilutive shares excluded from the dilutive computation	3			54		376			334

SHAREHOLDERS_EQUITY_TABLES

SHAREHOLDERS' EQUITY (TABLES)	9 Months Ended
	Sep. 30, 2014
Stockholders' Equity Note [Abstract]	'
COMMON SHARES ISSUED AND OUTSTANDING [Table Text Block]	'
			Three months ended September 30,					Nine months ended September 30,
			2014		2013			2014			2013
		Shares issued, balance at beginning of period	175,315		173,906			174,134			171,867
		Shares issued	84		71			1,265			2,110
		Total shares issued at end of period	175,399		173,977			175,399			173,977
		Treasury shares, balance at beginning of period	(71,409	)	(62,318	)		(64,649	)		(53,947	)
		Shares repurchased	(3,169	)	(11	)		(10,263	)		(8,502	)
		Shares reissued from treasury	6		3			340			123
		Total treasury shares at end of period	(74,572	)	(62,326	)		(74,572	)		(62,326	)
		Total shares outstanding	100,827		111,651			100,827			111,651
SHARE REPURCHASES [Table Text Block]	'
			Three months ended September 30,							Nine months ended September 30,
			2014			2013				2014			2013
		In the open market:
		Total shares	3,159			—				9,838			5,048
		Total cost	$	150,000		$	—			$	450,000		$	225,000
		Average price per share(1)	$	47.49		$	—			$	45.74		$	44.57
		From employees:
		Total shares	10			11				425			454
		Total cost	$	449		$	489			$	18,532		$	18,413
		Average price per share(1)	$	45.39		$	44.12			$	43.65		$	40.56
		From founding shareholder:(2)
		Total shares	—			—				—			3,000
		Total cost	$	—		$	—			$	—		$	116,100
		Average price per share(1)	$	—		$	—			$	—		$	38.7
		Total shares repurchased:
		Total shares	3,169			11				10,263			8,502
		Total cost	$	150,449		$	489			$	468,532		$	359,513
		Average price per share(1)	$	47.48		$	44.12			$	45.65		$	42.29
	-1	Calculated using whole figures.
	(2) During the first quarter of 2013, we privately negotiated the repurchase of 3,000,000 common shares held by Trident II, L.P. and affiliated entities.

NONCONTROLLING_INTEREST_TABLES

NONCONTROLLING INTEREST (TABLES)	9 Months Ended
	Sep. 30, 2014
Noncontrolling Interest [Abstract]	'
RECONCILIATION OF BEGINNING AND ENDING BALANCES OF NONCONTROLLING INTEREST [Table Text Block]	'
			Total
			2014
		Balance at January 1, 2014	$	50,000
		Increase from issuance of preferred equity to noncontrolling interests	25,000
		Decrease from return of capital to noncontrolling interests	(10,000		)
		Amounts attributable to (from) noncontrolling interests	(3,365		)
		Balance at September 30, 2014	$	61,635

OTHER_COMPREHENSIVE_INCOME_LOS1

OTHER COMPREHENSIVE INCOME (LOSS) (TABLES)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
TAX EFFECTS ALLOCATED TO EACH COMPONENT OF OTHER COMPREHENSIVE INCOME (LOSS) [Table Text Block]	'
			2014												2013
			Before Tax Amount				Tax (Expense) Benefit				Net of Tax Amount				Before Tax Amount				Tax (Expense) Benefit			Net of Tax Amount
		Three months ended September 30,
		Available for sale investments:
		Unrealized gains (losses) arising during the period	$	(176,278	)		$	9,218			$	(167,060	)		$	118,821			$	(8,181	)	$	110,640
		Adjustment for reclassification of net realized investment gains and OTTI losses recognized in net income	(74,306		)		1,636				(72,670		)		(8,215		)		(442		)	(8,657		)
		Unrealized gains (losses) arising during the period, net of reclassification adjustment	(250,584		)		10,854				(239,730		)		110,606				(8,623		)	101,983
		Non-credit portion of OTTI losses	—				—				—				—				—			—
		Foreign currency translation adjustment	(10,000		)		—				(10,000		)		3,635				—			3,635
		Total other comprehensive income (loss), net of tax	$	(260,584	)		$	10,854			$	(249,730	)		$	114,241			$	(8,623	)	$	105,618
		Nine months ended September 30,
		Available for sale investments:
		Unrealized gains (losses) arising during the period	$	37,858			$	(12,984	)		$	24,874			$	(188,808	)		$	18,022		$	(170,786	)
		Adjustment for reclassification of net realized investment gains and OTTI losses recognized in net income	(130,634		)		14,421				(116,213		)		(51,166		)		4,595			(46,571		)
		Unrealized losses arising during the period, net of reclassification adjustment	(92,776		)		1,437				(91,339		)		(239,974		)		22,617			(217,357		)
		Non-credit portion of OTTI losses	—				—				—				—				—			—
		Foreign currency translation adjustment	(3,551		)		—				(3,551		)		(14,892		)		—			(14,892		)
		Total other comprehensive loss, net of tax	$	(96,327	)		$	1,437			$	(94,890	)		$	(254,866	)		$	22,617		$	(232,249	)
RECLASSIFICATIONS OUT OF AOCI INTO NET INCOME AVAILABLE TO COMMON SHAREHOLDERS [Table Text Block]	'
				Amount Reclassified from AOCI(1)
		Details About AOCI Components	Consolidated Statement of Operations Line Item That Includes Reclassification	Three months ended September 30,								Nine months ended September 30,
				2014				2013				2014				2013
		Unrealized appreciation on available for sale investments
			Other realized investment gains (losses)	$	83,737			$	11,026			$	142,755			$	60,002
			OTTI losses	(9,431		)		(2,811		)		(12,121		)		(8,836		)
			Total before tax	74,306				8,215				130,634				51,166
			Income tax expense (benefit)	(1,636		)		442				(14,421		)		(4,595		)
			Net of tax	$	72,670			$	8,657			$	116,213			$	46,571
	-1	Amounts in parentheses are debits to net income available to common shareholders.

SEGMENT_INFORMATION_DETAILS

SEGMENT INFORMATION (DETAILS) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
			reportable_segment
Segment Information [Line Items]	'	'	'	'	'
Number of reportable segments	'	'	2	'	'
Net premiums earned	$966,138	$945,242	$2,912,482	$2,765,154	'
Other insurance related income	7,702	725	12,468	1,756	'
Net losses and loss expenses	-552,064	-501,522	-1,662,097	-1,582,835	'
Acquisition costs	-185,950	-173,682	-549,848	-488,892	'
General and administrative expenses	-152,916	-140,699	-456,725	-431,207	'
Net investment income	66,562	103,429	264,171	295,450	'
Net realized investment gains (losses)	77,448	-4,708	121,329	56,004	'
Foreign exchange (losses) gains	72,292	-56,860	58,353	-11,659	'
Interest expense and financing costs	-20,344	-15,260	-56,913	-46,355	'
Income before income taxes	278,868	156,665	643,220	557,416	'
Net loss and loss expense ratio	57.10%	53.10%	57.10%	57.20%	'
Acquisition cost ratio	19.20%	18.40%	18.90%	17.70%	'
General and administrative expense ratio	15.90%	14.80%	15.60%	15.60%	'
Combined ratio	92.20%	86.30%	91.60%	90.50%	'
Goodwill and intangible assets	88,740	91,656	88,740	91,656	89,528
Operating Segments [Member]	'	'	'	'	'
Segment Information [Line Items]	'	'	'	'	'
Gross premiums written	896,814	904,797	3,949,479	3,871,085	'
Net premiums written	687,223	716,389	3,351,958	3,280,236	'
Net premiums earned	966,138	945,242	2,912,482	2,765,154	'
Other insurance related income	7,702	725	12,468	1,756	'
Net losses and loss expenses	-552,064	-501,522	-1,662,097	-1,582,835	'
Acquisition costs	-185,950	-173,682	-549,848	-488,892	'
General and administrative expenses	-122,362	-117,675	-364,195	-361,373	'
Underwriting income	113,464	153,088	348,810	333,810	'
Operating Segments [Member] | Insurance [Member]	'	'	'	'	'
Segment Information [Line Items]	'	'	'	'	'
Gross premiums written	555,283	574,778	1,911,102	1,952,548	'
Net premiums written	363,571	393,627	1,361,351	1,385,892	'
Net premiums earned	461,805	448,072	1,368,683	1,272,297	'
Other insurance related income	0	725	0	1,756	'
Net losses and loss expenses	-289,207	-216,440	-859,093	-764,768	'
Acquisition costs	-71,264	-61,087	-207,360	-177,097	'
General and administrative expenses	-85,750	-82,548	-257,208	-257,962	'
Underwriting income	15,584	88,722	45,022	74,226	'
Net loss and loss expense ratio	62.60%	48.30%	62.80%	60.10%	'
Acquisition cost ratio	15.40%	13.60%	15.20%	13.90%	'
General and administrative expense ratio	18.60%	18.50%	18.70%	20.30%	'
Combined ratio	96.60%	80.40%	96.70%	94.30%	'
Goodwill and intangible assets	88,740	91,656	88,740	91,656	'
Operating Segments [Member] | Reinsurance [Member]	'	'	'	'	'
Segment Information [Line Items]	'	'	'	'	'
Gross premiums written	341,531	330,019	2,038,377	1,918,537	'
Net premiums written	323,652	322,762	1,990,607	1,894,344	'
Net premiums earned	504,333	497,170	1,543,799	1,492,857	'
Other insurance related income	7,702	0	12,468	0	'
Net losses and loss expenses	-262,857	-285,082	-803,004	-818,067	'
Acquisition costs	-114,686	-112,595	-342,488	-311,795	'
General and administrative expenses	-36,612	-35,127	-106,987	-103,411	'
Underwriting income	97,880	64,366	303,788	259,584	'
Net loss and loss expense ratio	52.10%	57.30%	52.00%	54.80%	'
Acquisition cost ratio	22.70%	22.60%	22.20%	20.90%	'
General and administrative expense ratio	7.30%	7.20%	6.90%	6.90%	'
Combined ratio	82.10%	87.10%	81.10%	82.60%	'
Goodwill and intangible assets	0	0	0	0	'
Corporate, Non-Segment [Member]	'	'	'	'	'
Segment Information [Line Items]	'	'	'	'	'
General and administrative expenses	-30,554	-23,024	-92,530	-69,834	'
Significant Reconciling Items [Member]	'	'	'	'	'
Segment Information [Line Items]	'	'	'	'	'
Net investment income	66,562	103,429	264,171	295,450	'
Net realized investment gains (losses)	77,448	-4,708	121,329	56,004	'
Foreign exchange (losses) gains	72,292	-56,860	58,353	-11,659	'
Interest expense and financing costs	($20,344)	($15,260)	($56,913)	($46,355)	'

INVESTMENTS_DETAILS

INVESTMENTS (DETAILS) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule Of Available For Sale Securities [Line Items]	'	'
Amortized Cost	$12,440,272	$11,987,146
Gross Unrealized Gains (fixed maturities)	142,381	179,218
Gross Unrealized Losses (fixed maturities)	-137,969	-180,037
Fair Value (fixed maturities)	12,444,684	11,986,327
Non-credit OTTI in AOCI	-888	-868
Cost	583,296	566,219
Gross Unrealized Gains (equities)	47,903	141,951
Gross Unrealized Losses (equities)	-1,697	-6,183
Fair Value (equities)	629,502	701,987
US Government and Agency [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Amortized Cost	1,545,328	1,421,245
Gross Unrealized Gains (fixed maturities)	1,564	1,405
Gross Unrealized Losses (fixed maturities)	-27,424	-33,952
Fair Value (fixed maturities)	1,519,468	1,388,698
Non-credit OTTI in AOCI	0	0
Non-US Government [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Amortized Cost	1,175,260	1,208,384
Gross Unrealized Gains (fixed maturities)	9,122	17,990
Gross Unrealized Losses (fixed maturities)	-45,460	-49,992
Fair Value (fixed maturities)	1,138,922	1,176,382
Non-credit OTTI in AOCI	0	0
Corporate Debt [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Amortized Cost	4,240,910	3,533,585
Gross Unrealized Gains (fixed maturities)	47,065	84,881
Gross Unrealized Losses (fixed maturities)	-37,179	-10,228
Fair Value (fixed maturities)	4,250,796	3,608,238
Non-credit OTTI in AOCI	0	0
Agency RMBS [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Amortized Cost	2,103,587	2,485,139
Gross Unrealized Gains (fixed maturities)	28,931	21,979
Gross Unrealized Losses (fixed maturities)	-11,571	-58,291
Fair Value (fixed maturities)	2,120,947	2,448,827
Non-credit OTTI in AOCI	0	0
CMBS [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Amortized Cost	945,134	790,095
Gross Unrealized Gains (fixed maturities)	12,212	11,285
Gross Unrealized Losses (fixed maturities)	-2,829	-3,966
Fair Value (fixed maturities)	954,517	797,414
Non-credit OTTI in AOCI	0	0
Non-Agency RMBS [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Amortized Cost	75,452	65,590
Gross Unrealized Gains (fixed maturities)	3,531	2,375
Gross Unrealized Losses (fixed maturities)	-588	-398
Fair Value (fixed maturities)	78,395	67,567
Non-credit OTTI in AOCI	-888	-868
ABS [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Amortized Cost	1,443,932	955,274
Gross Unrealized Gains (fixed maturities)	3,775	6,871
Gross Unrealized Losses (fixed maturities)	-11,842	-8,694
Fair Value (fixed maturities)	1,435,865	953,451
Non-credit OTTI in AOCI	0	0
Municipals [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Amortized Cost	910,669	1,527,834
Gross Unrealized Gains (fixed maturities)	36,181	32,432
Gross Unrealized Losses (fixed maturities)	-1,076	-14,516
Fair Value (fixed maturities)	945,774	1,545,750
Non-credit OTTI in AOCI	0	0
Common Stock [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Cost	49,426	345,759
Gross Unrealized Gains (equities)	14,367	98,742
Gross Unrealized Losses (equities)	-648	-6,183
Fair Value (equities)	63,145	438,318
Exchange-Traded Funds [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Cost	420,219	106,762
Gross Unrealized Gains (equities)	31,506	32,085
Gross Unrealized Losses (equities)	-1,049	0
Fair Value (equities)	450,676	138,847
Non-U.S. Bond Mutual Funds [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Cost	113,651	113,698
Gross Unrealized Gains (equities)	2,030	11,124
Gross Unrealized Losses (equities)	0	0
Fair Value (equities)	$115,681	$124,822

INVESTMENTS_DETAILS_2

INVESTMENTS (DETAILS 2) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule Of Available For Sale Securities [Line Items]	'	'
Due in one year or less (amortized cost)	$550,351	$710,079
Due after one year through five years (amortized cost)	5,250,453	5,030,728
Due after five years through ten years (amortized cost)	1,822,740	1,852,877
Due after ten years (amortized cost)	248,623	97,364
Total fixed maturities with a single maturity date (amortized cost)	7,872,167	7,691,048
Total (amortized cost)	12,440,272	11,987,146
Due in one year or less (fair value)	549,150	717,052
Due after one year through five years (fair value)	5,266,397	5,116,060
Due after five years through ten years (fair value)	1,788,151	1,791,835
Due after ten years (fair value)	251,262	94,121
Total fixed maturities with a single maturity date (fair value)	7,854,960	7,719,068
Fair Value (fixed maturities)	12,444,684	11,986,327
Due in one year or less (% of total fair value)	4.50%	5.90%
Due after one year through five years (% of total fair value)	42.30%	42.70%
Due after five years through ten years (% of total fair value)	14.40%	14.90%
Due after ten years (% of total fair value)	2.00%	0.80%
Fixed maturities with a single maturity date (% of total fair value)	63.20%	64.30%
Total	100.00%	100.00%
Agency RMBS [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fixed maturities without a single maturity date (amortized cost)	2,103,587	2,485,139
Total (amortized cost)	2,103,587	2,485,139
Fixed maturities without a single maturity date (fair value)	2,120,947	2,448,827
Fair Value (fixed maturities)	2,120,947	2,448,827
Fixed maturities without a single maturity date (% of total fair value)	17.00%	20.40%
CMBS [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fixed maturities without a single maturity date (amortized cost)	945,134	790,095
Total (amortized cost)	945,134	790,095
Fixed maturities without a single maturity date (fair value)	954,517	797,414
Fair Value (fixed maturities)	954,517	797,414
Fixed maturities without a single maturity date (% of total fair value)	7.70%	6.70%
Non-Agency RMBS [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fixed maturities without a single maturity date (amortized cost)	75,452	65,590
Total (amortized cost)	75,452	65,590
Fixed maturities without a single maturity date (fair value)	78,395	67,567
Fair Value (fixed maturities)	78,395	67,567
Fixed maturities without a single maturity date (% of total fair value)	0.60%	0.60%
ABS [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fixed maturities without a single maturity date (amortized cost)	1,443,932	955,274
Total (amortized cost)	1,443,932	955,274
Fixed maturities without a single maturity date (fair value)	1,435,865	953,451
Fair Value (fixed maturities)	$1,435,865	$953,451
Fixed maturities without a single maturity date (% of total fair value)	11.50%	8.00%

INVESTMENTS_DETAILS_3

INVESTMENTS (DETAILS 3) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	security	security
Fixed Maturities [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fair Value - 12 months or greater	$1,416,300	$271,520
Unrealized Losses - 12 months or greater	-72,037	-13,466
Fair Value - Less than 12 months	4,697,191	4,889,507
Unrealized Losses - Less than 12 months	-65,932	-166,571
Total Fair Value of Securities in Unrealized Loss Position	6,113,491	5,161,027
Total Unrealized Losses	-137,969	-180,037
Number of Available For Sale Securities In Unrealized Loss Positions	1,306	1,127
Number of Available For Sale Securities in Unrealized Loss Positions for 12 Months or Greater	281	99
Fixed Maturities [Member] | Below Investment Grade or Not Rated [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Total Unrealized Losses	-14,000	-2,000
US Government and Agency [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fair Value - 12 months or greater	392,084	0
Unrealized Losses - 12 months or greater	-23,150	0
Fair Value - Less than 12 months	864,003	982,307
Unrealized Losses - Less than 12 months	-4,274	-33,952
Total Fair Value of Securities in Unrealized Loss Position	1,256,087	982,307
Total Unrealized Losses	-27,424	-33,952
Non-US Government [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fair Value - 12 months or greater	148,526	35,577
Unrealized Losses - 12 months or greater	-25,903	-3,430
Fair Value - Less than 12 months	395,307	420,622
Unrealized Losses - Less than 12 months	-19,557	-46,562
Total Fair Value of Securities in Unrealized Loss Position	543,833	456,199
Total Unrealized Losses	-45,460	-49,992
Corporate Debt [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fair Value - 12 months or greater	35,841	27,696
Unrealized Losses - 12 months or greater	-2,608	-802
Fair Value - Less than 12 months	2,006,740	606,592
Unrealized Losses - Less than 12 months	-34,571	-9,426
Total Fair Value of Securities in Unrealized Loss Position	2,042,581	634,288
Total Unrealized Losses	-37,179	-10,228
Agency RMBS [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fair Value - 12 months or greater	335,687	144,468
Unrealized Losses - 12 months or greater	-9,617	-5,247
Fair Value - Less than 12 months	469,445	1,478,527
Unrealized Losses - Less than 12 months	-1,954	-53,044
Total Fair Value of Securities in Unrealized Loss Position	805,132	1,622,995
Total Unrealized Losses	-11,571	-58,291
CMBS [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fair Value - 12 months or greater	77,827	13,319
Unrealized Losses - 12 months or greater	-1,066	-116
Fair Value - Less than 12 months	310,078	298,863
Unrealized Losses - Less than 12 months	-1,763	-3,850
Total Fair Value of Securities in Unrealized Loss Position	387,905	312,182
Total Unrealized Losses	-2,829	-3,966
Non-Agency RMBS [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fair Value - 12 months or greater	8,217	4,287
Unrealized Losses - 12 months or greater	-524	-315
Fair Value - Less than 12 months	3,087	5,319
Unrealized Losses - Less than 12 months	-64	-83
Total Fair Value of Securities in Unrealized Loss Position	11,304	9,606
Total Unrealized Losses	-588	-398
ABS [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fair Value - 12 months or greater	378,668	37,765
Unrealized Losses - 12 months or greater	-8,122	-2,941
Fair Value - Less than 12 months	640,305	553,803
Unrealized Losses - Less than 12 months	-3,720	-5,753
Total Fair Value of Securities in Unrealized Loss Position	1,018,973	591,568
Total Unrealized Losses	-11,842	-8,694
Municipals [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fair Value - 12 months or greater	39,450	8,408
Unrealized Losses - 12 months or greater	-1,047	-615
Fair Value - Less than 12 months	8,226	543,474
Unrealized Losses - Less than 12 months	-29	-13,901
Total Fair Value of Securities in Unrealized Loss Position	47,676	551,882
Total Unrealized Losses	-1,076	-14,516
Equity Securities [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fair Value - 12 months or greater	1,828	3,499
Unrealized Losses - 12 months or greater	-249	-398
Fair Value - Less than 12 months	66,475	48,828
Unrealized Losses - Less than 12 months	-1,448	-5,785
Total Fair Value of Securities in Unrealized Loss Position	68,303	52,327
Total Unrealized Losses	-1,697	-6,183
Number of Available For Sale Securities In Unrealized Loss Positions	9	63
Number of Available For Sale Securities in Unrealized Loss Positions for 12 Months or Greater	2	9
Common Stock [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fair Value - 12 months or greater	1,828	3,499
Unrealized Losses - 12 months or greater	-249	-398
Fair Value - Less than 12 months	10,401	48,828
Unrealized Losses - Less than 12 months	-399	-5,785
Total Fair Value of Securities in Unrealized Loss Position	12,229	52,327
Total Unrealized Losses	-648	-6,183
Exchange-Traded Funds [Member]	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'
Fair Value - 12 months or greater	0	0
Unrealized Losses - 12 months or greater	0	0
Fair Value - Less than 12 months	56,074	0
Unrealized Losses - Less than 12 months	-1,049	0
Total Fair Value of Securities in Unrealized Loss Position	56,074	0
Total Unrealized Losses	($1,049)	$0

INVESTMENTS_DETAILS_4

INVESTMENTS (DETAILS 4) (USD $)

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2013

Hedge Funds [Member]

Hedge Funds [Member]

Hedge Funds [Member]

Hedge Funds [Member]

Long/short equity funds [Member]

Long/short equity funds [Member]

Long/short equity funds [Member]

Long/short equity funds [Member]

Long/short equity funds [Member]

Long/short equity funds [Member]

Multi-strategy funds [Member]

Multi-strategy funds [Member]

Multi-strategy funds [Member]

Multi-strategy funds [Member]

Multi-strategy funds [Member]

Multi-strategy funds [Member]

Multi-strategy funds [Member]

Multi-strategy funds [Member]

Event driven funds [Member]

Event driven funds [Member]

Event driven funds [Member]

Event driven funds [Member]

Event driven funds [Member]

Event driven funds [Member]

Leveraged bank loan funds [Member]

Leveraged bank loan funds [Member]

Direct Lending Funds [Member]

Direct Lending Funds [Member]

Direct Lending Funds [Member]

Direct Lending Funds [Member]

Direct Lending Funds [Member]

Direct Lending Funds [Member]

CLO-Equities [Member]

CLO-Equities [Member]

CLO-Equities [Member]

CLO-Equities [Member]

Lockup Redemption Restriction [Member]

Lockup Redemption Restriction [Member]

Other Redemption Restriction [Member]

Other Redemption Restriction [Member]

Minimum [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

Other Redemption Restriction [Member]

Other Redemption Restriction [Member]

Minimum [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

Minimum [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

Other Redemption Restriction [Member]

Other Redemption Restriction [Member]

Minimum [Member]

Maximum [Member]

Other Redemption Restriction [Member]

Other Redemption Restriction [Member]

Other Investments [Line Items]

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'

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'

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'

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Other investments

$946,836,000

$1,045,810,000

'

'

'

'

$292,086,000

$425,444,000

'

'

'

'

$315,480,000

$285,155,000

'

'

'

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'

$188,397,000

$190,458,000

'

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'

$9,904,000

$48,753,000

$43,836,000

$22,134,000

'

'

'

'

$97,133,000

$73,866,000

'

'

Percentage of total fair value

100.00%

100.00%

'

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'

'

31.00%

41.00%

'

'

'

'

33.00%

27.00%

'

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'

'

'

'

20.00%

18.00%

'

'

'

'

1.00%

5.00%

5.00%

2.00%

'

'

'

'

10.00%

7.00%

'

'

Redemption frequency

'

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'

'Quarterly, Semi-annually

'Monthly, Quarterly, Semi-annually

'

'

'

'

'Quarterly, Semi-annually

'Quarterly, Semi-annually

'

'

'

'

'

'

'Quarterly, Annually

'Quarterly, Annually

'

'

'

'

'Quarterly

'Quarterly

'

'

'

'

'

'

'

'

'

'

Redemption notice period

'

'

'

'

'

'

'

'

'45 days

'30 days

'60 days

'60 days

'

'

'

'

'60 days

'60 days

'95 days

'95 days

'

'

'45 days

'45 days

'60 days

'60 days

'65 days

'65 days

'

'

'

'

'

'

'

'

'

'

Fair value of other investments subject to redemption restrictions

'

'

71,000,000

99,000,000

6,000,000

11,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

43,836,000

22,134,000

'

'

'

'

'

'

Percentage of fair value of other investments subject to redemption restrictions

'

'

9.00%

10.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.00%

2.00%

'

'

'

'

'

'

Unfunded commitments related to other investments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$41,000,000

$60,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$67,000,000

$88,000,000

'

'

'

'

$0

$60,000,000

Investment term

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'5 years

'10 years

'

'

'

'

Optional extension of investment term

'

'

'

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

INVESTMENTS_DETAILS_5

INVESTMENTS (DETAILS 5) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net Investment Income [Line Items]	'	'	'	'
Gross investment income	$75,856	$111,198	$291,679	$318,673
Investment expenses	-9,294	-7,769	-27,508	-23,223
Net investment income	66,562	103,429	264,171	295,450
Fixed Maturities [Member]	'	'	'	'
Net Investment Income [Line Items]	'	'	'	'
Gross investment income	74,996	74,691	226,475	218,877
Other Investments [Member]	'	'	'	'
Net Investment Income [Line Items]	'	'	'	'
Gross investment income	-3,384	32,127	45,868	87,406
Equity Securities [Member]	'	'	'	'
Net Investment Income [Line Items]	'	'	'	'
Gross investment income	2,022	3,871	9,609	8,419
Cash And Cash Equivalents [Member]	'	'	'	'
Net Investment Income [Line Items]	'	'	'	'
Gross investment income	2,081	382	9,127	2,915
Short-term Investments [Member]	'	'	'	'
Net Investment Income [Line Items]	'	'	'	'
Gross investment income	$141	$127	$600	$1,056

INVESTMENTS_DETAILS_6

INVESTMENTS (DETAILS 6) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Schedule Of Available For Sale Securities [Line Items]	'	'	'	'
Gross realized gains	$99,526	$39,616	$211,821	$142,883
Gross realized losses	-15,647	-28,455	-68,727	-82,277
Net OTTI recognized in earnings	-9,431	-2,811	-12,121	-8,836
Change in fair value of investment derivatives	3,000	-13,058	-9,644	4,234
Total net realized investment gains (losses)	77,448	-4,708	121,329	56,004
Fixed Maturities And Short-Term Investments [Member]	'	'	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'	'	'
Gross realized gains	17,638	27,631	78,057	94,617
Gross realized losses	-8,527	-26,454	-56,623	-73,266
Equity Securities [Member]	'	'	'	'
Schedule Of Available For Sale Securities [Line Items]	'	'	'	'
Gross realized gains	81,888	11,985	133,764	48,266
Gross realized losses	($7,120)	($2,001)	($12,104)	($9,011)

INVESTMENTS_DETAILS_7

INVESTMENTS (DETAILS 7) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]	'	'	'	'
Total OTTI recognized in earnings	$9,431	$2,811	$12,121	$8,836
Fixed Maturities [Member]	'	'	'	'
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]	'	'	'	'
Total OTTI recognized in earnings	4,829	2,601	6,778	6,706
Non-US Government [Member]	'	'	'	'
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]	'	'	'	'
Total OTTI recognized in earnings	3,380	94	5,192	120
Corporate Debt [Member]	'	'	'	'
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]	'	'	'	'
Total OTTI recognized in earnings	1,031	1,811	1,112	5,761
Non-Agency RMBS [Member]	'	'	'	'
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]	'	'	'	'
Total OTTI recognized in earnings	0	57	0	57
ABS [Member]	'	'	'	'
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]	'	'	'	'
Total OTTI recognized in earnings	0	0	56	129
Municipals [Member]	'	'	'	'
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]	'	'	'	'
Total OTTI recognized in earnings	418	639	418	639
Equity Securities [Member]	'	'	'	'
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]	'	'	'	'
Total OTTI recognized in earnings	4,602	210	5,343	2,130
Common Stock [Member]	'	'	'	'
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]	'	'	'	'
Total OTTI recognized in earnings	0	207	741	1,607
Exchange-Traded Funds [Member]	'	'	'	'
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net [Line Items]	'	'	'	'
Total OTTI recognized in earnings	$4,602	$3	$4,602	$523

INVESTMENTS_DETAILS_8

INVESTMENTS (DETAILS 8) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Credit Losses For Which a Portion of OTTI Was Recognized in AOCI [Roll Forward]	'	'	'	'
Balance at beginning of period	$1,581	$1,699	$1,594	$1,809
Credit impairments recognized on securities not previously impaired	0	0	0	0
Additional credit impairments recognized on securities previously impaired	0	0	0	0
Change in timing of future cash flows on securities previously impaired	0	0	0	0
Intent to sell of securities previously impaired	0	0	0	0
Securities sold/redeemed/matured	-23	-110	-36	-220
Balance at end of period	$1,558	$1,589	$1,558	$1,589

INVESTMENTS_DETAILS_9

INVESTMENTS (DETAILS 9) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]	'	'
Value of reverse repurchase agreements	$101	$34
Minimum required collateral for reverse repurchase agreements, expressed as a percentage of loan principal	102.00%	'

FAIR_VALUE_MEASUREMENTS_DETAIL

FAIR VALUE MEASUREMENTS (DETAILS) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	$12,444,684	$11,986,327
Equity securities	629,502	701,987
Other investments	946,836	1,045,810
Short-term investments	114,428	46,212
Derivative assets (see Note 5)	16,819	7,808
Derivative liabilities (see Note 5)	18,115	1,967
Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	12,444,684	11,986,327
Equity securities	629,502	701,987
Other investments	946,836	1,045,810
Short-term investments	114,428	46,212
Derivative assets (see Note 5)	16,819	7,808
Total assets	14,152,269	13,788,144
Derivative liabilities (see Note 5)	18,115	1,967
Cash settled awards (see Note 7)	14,106	8,693
Total liabilities	32,221	10,660
US Government and Agency [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	1,519,468	1,388,698
US Government and Agency [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	1,519,468	1,388,698
Non-US Government [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	1,138,922	1,176,382
Non-US Government [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	1,138,922	1,176,382
Corporate Debt [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	4,250,796	3,608,238
Corporate Debt [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	4,250,796	3,608,238
Agency RMBS [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	2,120,947	2,448,827
Agency RMBS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	2,120,947	2,448,827
CMBS [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	954,517	797,414
CMBS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	954,517	797,414
Non-Agency RMBS [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	78,395	67,567
Non-Agency RMBS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	78,395	67,567
ABS [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	1,435,865	953,451
ABS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	1,435,865	953,451
Municipals [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	945,774	1,545,750
Municipals [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	945,774	1,545,750
Common Stock [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	63,145	438,318
Common Stock [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	63,145	438,318
Exchange-Traded Funds [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	450,676	138,847
Exchange-Traded Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	450,676	138,847
Non-U.S. Bond Mutual Funds [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	115,681	124,822
Non-U.S. Bond Mutual Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	115,681	124,822
Hedge Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Other investments	805,867	949,810
Direct Lending Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Other investments	43,836	22,134
CLO-Equities [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Other investments	97,133	73,866
Level 1 [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	1,390,737	1,119,632
Equity securities	513,821	577,165
Other investments	0	0
Short-term investments	0	0
Derivative assets (see Note 5)	0	0
Total assets	1,904,558	1,696,797
Derivative liabilities (see Note 5)	0	0
Cash settled awards (see Note 7)	0	0
Total liabilities	0	0
Level 1 [Member] | US Government and Agency [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	1,390,737	1,119,632
Level 1 [Member] | Non-US Government [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 1 [Member] | Corporate Debt [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 1 [Member] | Agency RMBS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 1 [Member] | CMBS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 1 [Member] | Non-Agency RMBS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 1 [Member] | ABS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 1 [Member] | Municipals [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 1 [Member] | Common Stock [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	63,145	438,318
Level 1 [Member] | Exchange-Traded Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	450,676	138,847
Level 1 [Member] | Non-U.S. Bond Mutual Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	0	0
Level 1 [Member] | Hedge Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Other investments	0	0
Level 1 [Member] | Direct Lending Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Other investments	0	0
Level 1 [Member] | CLO-Equities [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Other investments	0	0
Level 2 [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	10,978,792	10,831,878
Equity securities	115,681	124,822
Other investments	361,376	488,755
Short-term investments	114,428	46,212
Derivative assets (see Note 5)	16,591	6,824
Total assets	11,586,868	11,498,491
Derivative liabilities (see Note 5)	10,469	1,152
Cash settled awards (see Note 7)	14,106	8,693
Total liabilities	24,575	9,845
Level 2 [Member] | US Government and Agency [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	128,731	269,066
Level 2 [Member] | Non-US Government [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	1,138,922	1,176,382
Level 2 [Member] | Corporate Debt [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	4,250,796	3,608,238
Level 2 [Member] | Agency RMBS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	2,120,947	2,448,827
Level 2 [Member] | CMBS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	939,897	793,396
Level 2 [Member] | Non-Agency RMBS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	78,395	67,567
Level 2 [Member] | ABS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	1,375,330	922,652
Level 2 [Member] | Municipals [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	945,774	1,545,750
Level 2 [Member] | Common Stock [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	0	0
Level 2 [Member] | Exchange-Traded Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	0	0
Level 2 [Member] | Non-U.S. Bond Mutual Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	115,681	124,822
Level 2 [Member] | Hedge Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Other investments	361,376	488,755
Level 2 [Member] | Direct Lending Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Other investments	0	0
Level 2 [Member] | CLO-Equities [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Other investments	0	0
Level 3 [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	75,155	34,817
Equity securities	0	0
Other investments	585,460	557,055
Short-term investments	0	0
Derivative assets (see Note 5)	228	984
Total assets	660,843	592,856
Derivative liabilities (see Note 5)	7,646	815
Cash settled awards (see Note 7)	0	0
Total liabilities	7,646	815
Level 3 [Member] | US Government and Agency [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 3 [Member] | Non-US Government [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 3 [Member] | Corporate Debt [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 3 [Member] | Agency RMBS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 3 [Member] | CMBS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	14,620	4,018
Level 3 [Member] | Non-Agency RMBS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 3 [Member] | ABS [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	60,535	30,799
Level 3 [Member] | Municipals [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Fixed maturities	0	0
Level 3 [Member] | Common Stock [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	0	0
Level 3 [Member] | Exchange-Traded Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	0	0
Level 3 [Member] | Non-U.S. Bond Mutual Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Equity securities	0	0
Level 3 [Member] | Hedge Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Other investments	444,491	461,055
Level 3 [Member] | Direct Lending Funds [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Other investments	43,836	22,134
Level 3 [Member] | CLO-Equities [Member] | Fair Value Measurements Recurring [Member]	'	'
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]	'	'
Other investments	$97,133	$73,866

FAIR_VALUE_MEASUREMENTS_DETAIL1

FAIR VALUE MEASUREMENTS (DETAILS 2) (USD $)

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

In Thousands, unless otherwise specified

Level 3 [Member]

Level 3 [Member]

Discounted cash flow [Member]

Discounted cash flow [Member]

Broker-dealer quote [Member]

Net asset value [Member]

Simulation model [Member]

Minimum [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

Weighted Average [Member]

Weighted Average [Member]

ABS - CLO Debt [Member]

Other Investments - CLO-Equities [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Discounted cash flow [Member]

Simulation model [Member]

Discounted cash flow [Member]

Simulation model [Member]

Discounted cash flow [Member]

Discounted cash flow [Member]

ABS - CLO Debt [Member]

Other Investments - CLO-Equities [Member]

ABS - CLO Debt [Member]

Other Investments - CLO-Equities [Member]

Weather Related Derivative [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Other Investments - CLO-Equities [Member]

Weather Related Derivative [Member]

Other Investments - CLO-Equities [Member]

Weather Related Derivative [Member]

ABS - CLO Debt [Member]

Other Investments - CLO-Equities [Member]

Fair Value Inputs Assets Quantitative Information [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fixed maturities

$12,444,684

$11,986,327

$60,535

'

$17,810

'

$42,725

'

'

'

'

'

'

'

'

Other investments

946,836

1,045,810

'

97,133

'

37,420

'

59,713

'

'

'

'

'

'

'

Net derivative assets

'

'

'

'

'

'

'

'

($7,418)

'

'

'

'

'

'

Credit spread

'

'

'

'

3.40%

'

'

'

'

'

'

'

'

3.40%

'

Illiquidity discount

'

'

'

'

5.00%

'

'

'

'

'

'

'

'

5.00%

'

Default rates

'

'

'

'

'

'

'

'

'

4.00%

'

5.00%

'

'

4.30%

Loss severity rate

'

'

'

'

'

53.50%

'

'

'

'

'

'

'

'

53.50%

Collateral spreads

'

'

'

'

'

'

'

'

'

2.60%

'

3.50%

'

'

3.30%

Estimated maturity dates (years)

'

'

'

'

'

'

'

'

'

'3 years 2 months 5 days

'

'4 years 4 months 13 days

'

'

'3 years 10 months 24 days

Weather curve

'

'

'

'

'

'

'

'

'

'

33

'

2,930

'

'

Weather standard deviation

'

'

'

'

'

'

'

'

'

'

3

'

305

'

'

FAIR_VALUE_MEASUREMENTS_DETAIL2

FAIR VALUE MEASUREMENTS (DETAILS 3) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fixed Maturities [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	$34,816	$65,910	$34,817	$70,931
Transfers into Level 3	52,834	34,700	52,962	43,082
Transfers out of Level 3	0	-6,915	0	-221,350
Included in earnings	0	0	0	1,438
Included in OCI	851	952	986	1,921
Purchases	0	0	0	212,889
Sales	0	0	0	-13,290
Settlements / distributions	-13,346	-21,082	-13,610	-22,056
Balance at end of period	75,155	73,565	75,155	73,565
Change in unrealized investment gain/loss relating to assets held at the reporting date	0	0	0	0
Other Investments [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	601,381	501,496	557,055	422,431
Transfers into Level 3	0	0	0	29,953
Transfers out of Level 3	-32,255	0	-32,255	0
Included in earnings	2,151	19,888	35,324	60,403
Included in OCI	0	0	0	0
Purchases	22,760	32,020	60,272	86,252
Sales	0	0	0	0
Settlements / distributions	-8,577	-31,892	-34,936	-77,527
Balance at end of period	585,460	521,512	585,460	521,512
Change in unrealized investment gain/loss relating to assets held at the reporting date	2,012	19,888	35,185	60,403
Other Assets [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	0	0	984	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in earnings	228	0	5,239	0
Included in OCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements / distributions	0	0	-5,995	0
Balance at end of period	228	0	228	0
Change in unrealized investment gain/loss relating to assets held at the reporting date	228	0	228	0
Total Assets [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	636,197	567,406	592,856	493,362
Transfers into Level 3	52,834	34,700	52,962	73,035
Transfers out of Level 3	-32,255	-6,915	-32,255	-221,350
Included in earnings	2,379	19,888	40,563	61,841
Included in OCI	851	952	986	1,921
Purchases	22,760	32,020	60,272	299,141
Sales	0	0	0	-13,290
Settlements / distributions	-21,923	-52,974	-54,541	-99,583
Balance at end of period	660,843	595,077	660,843	595,077
Change in unrealized investment gain/loss relating to assets held at the reporting date	2,240	19,888	35,413	60,403
Total Liabilities [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	750	0	815	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in earnings	-272	0	624	0
Included in OCI	0	0	0	0
Purchases	7,587	0	8,427	0
Sales	0	0	0	0
Settlements / distributions	-419	0	-2,220	0
Balance at end of period	7,646	0	7,646	0
Change in unrealized investment gain/loss relating to assets held at the reporting date	59	0	59	0
Corporate Debt [Member] | Fixed Maturities [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	0	0	0	1,550
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in earnings	0	0	0	1,550
Included in OCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	-3,100
Settlements / distributions	0	0	0	0
Balance at end of period	0	0	0	0
Change in unrealized investment gain/loss relating to assets held at the reporting date	0	0	0	0
Non-Agency RMBS [Member] | Fixed Maturities [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	0	0	0	1,110
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	-1,223
Included in earnings	0	0	0	0
Included in OCI	0	0	0	135
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements / distributions	0	0	0	-22
Balance at end of period	0	0	0	0
Change in unrealized investment gain/loss relating to assets held at the reporting date	0	0	0	0
CMBS [Member] | Fixed Maturities [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	3,933	11,785	4,018	4,296
Transfers into Level 3	10,795	0	10,795	8,382
Transfers out of Level 3	0	-6,915	0	-6,915
Included in earnings	0	0	0	0
Included in OCI	-31	-96	-74	-243
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements / distributions	-77	-714	-119	-1,460
Balance at end of period	14,620	4,060	14,620	4,060
Change in unrealized investment gain/loss relating to assets held at the reporting date	0	0	0	0
ABS [Member] | Fixed Maturities [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	30,883	54,125	30,799	63,975
Transfers into Level 3	42,039	34,700	42,167	34,700
Transfers out of Level 3	0	0	0	-213,212
Included in earnings	0	0	0	-112
Included in OCI	882	1,048	1,060	2,029
Purchases	0	0	0	212,889
Sales	0	0	0	-10,190
Settlements / distributions	-13,269	-20,368	-13,491	-20,574
Balance at end of period	60,535	69,505	60,535	69,505
Change in unrealized investment gain/loss relating to assets held at the reporting date	0	0	0	0
Hedge Funds [Member] | Other Investments [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	476,808	444,220	461,055	359,996
Transfers into Level 3	0	0	0	29,953
Transfers out of Level 3	-32,255	0	-32,255	0
Included in earnings	-4,205	13,233	16,718	38,723
Included in OCI	0	0	0	0
Purchases	6,000	0	13,500	50,000
Sales	0	0	0	0
Settlements / distributions	-1,857	-19,156	-14,527	-40,375
Balance at end of period	444,491	438,297	444,491	438,297
Change in unrealized investment gain/loss relating to assets held at the reporting date	-4,344	13,233	16,579	38,723
Direct Lending Funds [Member] | Other Investments [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	33,467	4,232	22,134	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in earnings	627	75	1,546	75
Included in OCI	0	0	0	0
Purchases	10,086	8,708	20,831	12,940
Sales	0	0	0	0
Settlements / distributions	-344	0	-675	0
Balance at end of period	43,836	13,015	43,836	13,015
Change in unrealized investment gain/loss relating to assets held at the reporting date	627	75	1,546	75
CLO-Equities [Member] | Other Investments [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	91,106	53,044	73,866	62,435
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in earnings	5,729	6,580	17,060	21,605
Included in OCI	0	0	0	0
Purchases	6,674	23,312	25,941	23,312
Sales	0	0	0	0
Settlements / distributions	-6,376	-12,736	-19,734	-37,152
Balance at end of period	97,133	70,200	97,133	70,200
Change in unrealized investment gain/loss relating to assets held at the reporting date	5,729	6,580	17,060	21,605
Derivative [Member] | Other Assets [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	0	0	984	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in earnings	228	0	5,239	0
Included in OCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements / distributions	0	0	-5,995	0
Balance at end of period	228	0	228	0
Change in unrealized investment gain/loss relating to assets held at the reporting date	228	0	228	0
Derivative [Member] | Other Liabilities [Member]	'	'	'	'
Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]	'	'	'	'
Balance at beginning of period	750	0	815	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Included in earnings	-272	0	624	0
Included in OCI	0	0	0	0
Purchases	7,587	0	8,427	0
Sales	0	0	0	0
Settlements / distributions	-419	0	-2,220	0
Balance at end of period	7,646	0	7,646	0
Change in unrealized investment gain/loss relating to assets held at the reporting date	$59	$0	$59	$0

FAIR_VALUE_MEASUREMENTS_DETAIL3

FAIR VALUE MEASUREMENTS (DETAILS 4) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Senior notes	$1,490,498	$995,855
Estimate Of Fair Value [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Senior notes	$1,593,000	$1,073,000

DERIVATIVE_INSTRUMENTS_DETAILS

DERIVATIVE INSTRUMENTS (DETAILS) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Asset Derivative Fair Value	$16,819	$7,808
Liability Derivative Fair Value	18,115	1,967
Other Assets [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Asset Derivative Fair Value	16,819	7,808
Other Liabilities [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Liability Derivative Fair Value	18,115	1,967
Investment Portfolio [Member] | Foreign Exchange Forward Contracts [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Derivative Notional Amount	167,105	254,023
Investment Portfolio [Member] | Foreign Exchange Forward Contracts [Member] | Other Assets [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Asset Derivative Fair Value	5,175	1,214
Investment Portfolio [Member] | Foreign Exchange Forward Contracts [Member] | Other Liabilities [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Liability Derivative Fair Value	11	1,032
Investment Portfolio [Member] | Interest Rate Swap [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Derivative Notional Amount	346,250	281,250
Investment Portfolio [Member] | Interest Rate Swap [Member] | Other Assets [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Asset Derivative Fair Value	0	873
Investment Portfolio [Member] | Interest Rate Swap [Member] | Other Liabilities [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Liability Derivative Fair Value	624	0
Underwriting Portfolio [Member] | Foreign Exchange Forward Contracts [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Derivative Notional Amount	616,539	390,663
Underwriting Portfolio [Member] | Foreign Exchange Forward Contracts [Member] | Other Assets [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Asset Derivative Fair Value	316	4,737
Underwriting Portfolio [Member] | Foreign Exchange Forward Contracts [Member] | Other Liabilities [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Liability Derivative Fair Value	9,834	120
Underwriting Portfolio [Member] | Weather Related Derivative [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Derivative Notional Amount	53,017	24,451
Underwriting Portfolio [Member] | Weather Related Derivative [Member] | Other Assets [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Asset Derivative Fair Value	228	984
Underwriting Portfolio [Member] | Weather Related Derivative [Member] | Other Liabilities [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Liability Derivative Fair Value	7,646	815
Underwriting Portfolio [Member] | Commodity Contract [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Derivative Notional Amount	100,850	0
Underwriting Portfolio [Member] | Commodity Contract [Member] | Other Assets [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Asset Derivative Fair Value	11,100	0
Underwriting Portfolio [Member] | Commodity Contract [Member] | Other Liabilities [Member] | Not Designated as Hedging Instruments [Member]	'	'
Derivative Fair Values on Consolidated Balance Sheet [Line Items]	'	'
Liability Derivative Fair Value	$0	$0

DERIVATIVE_INSTRUMENTS_DETAILS1

DERIVATIVE INSTRUMENTS (DETAILS 2) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'	'
Derivative assets - gross amounts	$25,823	$9,796
Derivative assets - gross amounts offset	-9,004	-1,988
Asset Derivative Fair Value	16,819	7,808
Derivative liabilities - gross amounts	27,119	3,955
Derivative liabilities - gross amounts offset	-9,004	-1,988
Liability Derivative Fair Value	$18,115	$1,967

DERIVATIVE_INSTRUMENTS_DETAILS2

DERIVATIVE INSTRUMENTS (DETAILS 3) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items]	'	'	'	'
Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges	($10,717)	($15,755)	($4,455)	($661)
Investment Portfolio [Member] | Foreign Exchange Forward Contracts [Member] | Net Realized Investment Gains (Losses) [Member]	'	'	'	'
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	7,034	-7,802	3,350	9,222
Investment Portfolio [Member] | Interest Rate Swap [Member] | Net Realized Investment Gains (Losses) [Member]	'	'	'	'
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	-4,034	-5,256	-12,994	-4,988
Underwriting Portfolio [Member] | Foreign Exchange Forward Contracts [Member] | Foreign Exchange Gains (Losses) [Member]	'	'	'	'
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	-21,915	-2,697	-8,784	-4,895
Underwriting Portfolio [Member] | Weather Related Derivative [Member] | Other Insurance Related Income [Member]	'	'	'	'
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	668	0	4,730	0
Underwriting Portfolio [Member] | Commodity Contract [Member] | Other Insurance Related Income [Member]	'	'	'	'
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	$7,530	$0	$9,243	$0

RESERVE_FOR_LOSSES_AND_LOSS_EX2

RESERVE FOR LOSSES AND LOSS EXPENSES (DETAILS) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reconciliation of Beginning and Ending Gross Unpaid Losses and Loss Expenses	'	'	'	'
Gross reserve for losses and loss expenses, beginning of period	'	'	$9,582,140	$9,058,731
Less reinsurance recoverable on unpaid losses, beginning of period	'	'	-1,900,112	-1,825,617
Net reserve for unpaid losses and loss expenses, beginning of period	'	'	7,682,028	7,233,114
Net incurred losses and loss expenses related to:	'	'	'	'
Current year	'	'	1,855,482	1,759,483
Prior years	-64,538	-80,035	-193,385	-176,648
Net incurred losses and loss expenses	'	'	1,662,097	1,582,835
Net paid losses and loss expenses related to:	'	'	'	'
Current year	'	'	-202,364	-168,564
Prior years	'	'	-1,165,215	-1,028,401
Net paid losses and loss expenses	'	'	-1,367,579	-1,196,965
Foreign exchange and other	'	'	-139,313	-17,265
Net reserve for unpaid losses and loss expenses, end of period	7,837,233	7,601,719	7,837,233	7,601,719
Reinsurance recoverable on unpaid losses, end of period	1,914,670	1,882,797	1,914,670	1,882,797
Gross reserve for losses and loss expenses, end of period	$9,751,903	$9,484,516	$9,751,903	$9,484,516

RESERVE_FOR_LOSSES_AND_LOSS_EX3

RESERVE FOR LOSSES AND LOSS EXPENSES (DETAILS 2) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net Favorable Prior Year Reserve Development [Line Items]	'	'	'	'
Net favorable prior year reserve development	$64,538	$80,035	$193,385	$176,648
Insurance [Member]	'	'	'	'
Net Favorable Prior Year Reserve Development [Line Items]	'	'	'	'
Net favorable prior year reserve development	9,488	34,065	54,059	46,355
Reinsurance [Member]	'	'	'	'
Net Favorable Prior Year Reserve Development [Line Items]	'	'	'	'
Net favorable prior year reserve development	$55,050	$45,970	$139,326	$130,293

RESERVE_FOR_LOSSES_AND_LOSS_EX4

RESERVE FOR LOSSES AND LOSS EXPENSES (DETAILS 3) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Additional Information Related to Net Incurred Losses [Line Items]	'	'	'	'
Net favorable (adverse) prior year reserve development	$64,538	$80,035	$193,385	$176,648
Short Tail Lines Insurance And Reinsurance Business [Member]	'	'	'	'
Additional Information Related to Net Incurred Losses [Line Items]	'	'	'	'
Net favorable (adverse) prior year reserve development	61,000	57,000	162,000	119,000
Liability Reinsurance Business [Member]	'	'	'	'
Additional Information Related to Net Incurred Losses [Line Items]	'	'	'	'
Net favorable (adverse) prior year reserve development	'	26,000	12,000	64,000
Professional Lines Reinsurance Business [Member]	'	'	'	'
Additional Information Related to Net Incurred Losses [Line Items]	'	'	'	'
Net favorable (adverse) prior year reserve development	10,000	10,000	22,000	20,000
Liability Insurance Business [Member]	'	'	'	'
Additional Information Related to Net Incurred Losses [Line Items]	'	'	'	'
Net favorable (adverse) prior year reserve development	-14,000	'	'	'
Credit And Surety Reinsurance Business [Member]	'	'	'	'
Additional Information Related to Net Incurred Losses [Line Items]	'	'	'	'
Net favorable (adverse) prior year reserve development	'	($15,000)	'	'

SHAREBASED_COMPENSATION_DETAIL

SHARE-BASED COMPENSATION (DETAILS) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]	'	'	'	'
Share based compensation expense incurred	$18,000,000	$14,000,000	$54,000,000	$45,000,000
Tax benefit related to share-based compensation costs incurred	4,000,000	3,000,000	10,000,000	8,000,000
Fair value - vested during period	'	'	66,000,000	68,000,000
Unrecognized share-based compensation costs	130,000,000	'	130,000,000	'
Unrecognized share-based compensation costs - weighted average period expected to be recognized	'	'	'2 years 5 months 1 day	'
Restricted Stock And Restricted Stock Units RSU [Member]	'	'	'	'
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]	'	'	'	'
Number of restricted stock and restricted stock units granted which will settle in cash	'	'	1,003,226	'
Liability for cash-settled units	$14,000,000	$6,000,000	$14,000,000	$6,000,000
Restricted Stock And Restricted Stock Units RSU [Member] | Performance [Member]	'	'	'	'
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]	'	'	'	'
Nonvested restricted stock (number) - beginning of period	'	'	283,000	'
Granted (number)	'	'	68,000	'
Vested (number)	'	'	0	'
Forfeited (number)	'	'	0	'
Nonvested restricted stock (number) - end of period	351,000	'	351,000	'
Weighted average grant date fair value - beginning of period	'	'	$35.74	'
Weighted average grant date fair value - granted	'	'	$44.33	'
Weighted average grant date fair value - vested	'	'	$0	'
Weighted average grant date fair value - forfeited	'	'	$0	'
Weighted average grant date fair value - end of period	$37.41	'	$37.41	'
Number of restricted stock and restricted stock units granted which will settle in cash	'	'	22,837	'
Restricted Stock And Restricted Stock Units RSU [Member] | Service [Member]	'	'	'	'
Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items]	'	'	'	'
Nonvested restricted stock (number) - beginning of period	'	'	3,430,000	'
Granted (number)	'	'	1,038,000	'
Vested (number)	'	'	-1,440,000	'
Forfeited (number)	'	'	-193,000	'
Nonvested restricted stock (number) - end of period	2,835,000	'	2,835,000	'
Weighted average grant date fair value - beginning of period	'	'	$34.72	'
Weighted average grant date fair value - granted	'	'	$44.42	'
Weighted average grant date fair value - vested	'	'	$33.82	'
Weighted average grant date fair value - forfeited	'	'	$36.77	'
Weighted average grant date fair value - end of period	$38.54	'	$38.54	'
Number of restricted stock and restricted stock units granted which will settle in cash	'	'	980,389	'

EARNINGS_PER_COMMON_SHARE_DETA

EARNINGS PER COMMON SHARE (DETAILS) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Basic earnings per common share	'	'	'	'
Net income	$282,966	$150,635	$633,693	$545,916
Less: noncontrolling interests	-6,160	0	-3,365	0
Less: preferred share dividends	10,022	13,514	30,066	30,452
Less: loss on repurchase of preferred shares	0	0	0	3,081
Net income available to common shareholders	279,104	137,121	606,992	512,383
Weighted average common shares outstanding - basic	102,945	111,676	105,683	114,606
Basic earnings per common share	$2.71	$1.23	$5.74	$4.47
Diluted earnings per common share	'	'	'	'
Net income available to common shareholders	$279,104	$137,121	$606,992	$512,383
Weighted average common shares outstanding - basic	102,945	111,676	105,683	114,606
Stock compensation plans	1,302	1,679	1,270	1,608
Weighted average common shares outstanding - diluted	104,247	113,355	106,953	116,214
Diluted earnings per common share	$2.68	$1.21	$5.68	$4.41
Anti-dilutive shares excluded from the dilutive computation	3	54	376	334

SHAREHOLDERS_EQUITY_DETAILS

SHAREHOLDERS' EQUITY (DETAILS)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
			Common Stock [Member]	Common Stock [Member]	Common Stock [Member]	Common Stock [Member]
Class of Stock [Line Items]	'	'	'	'	'	'
Shares issued, balance at beginning of period	175,399,000	174,134,000	175,315,000	173,906,000	174,134,000	171,867,000
Shares issued	'	'	84,000	71,000	1,265,000	2,110,000
Total shares issued at end of period	175,399,000	174,134,000	175,399,000	173,977,000	175,399,000	173,977,000
Treasury shares, balance at beginning of period	-74,572,000	-64,649,000	-71,409,000	-62,318,000	-64,649,000	-53,947,000
Shares repurchased	'	'	-3,169,000	-11,000	-10,263,000	-8,502,000
Shares reissued from treasury	'	'	6,000	3,000	340,000	123,000
Total treasury shares at end of period	-74,572,000	-64,649,000	-74,572,000	-62,326,000	-74,572,000	-62,326,000
Total shares outstanding	100,827,000	109,485,000	100,827,000	111,651,000	100,827,000	111,651,000

SHAREHOLDERS_EQUITY_DETAILS_2

SHAREHOLDERS' EQUITY (DETAILS 2) (Common Stock [Member], USD $)	3 Months Ended		9 Months Ended		3 Months Ended			9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
					Trident [Member]	In the Open Market [Member]	In the Open Market [Member]	In the Open Market [Member]	In the Open Market [Member]	From Employees [Member]	From Employees [Member]	From Employees [Member]	From Employees [Member]	From Founding Shareholder [Member]	From Founding Shareholder [Member]	From Founding Shareholder [Member]	From Founding Shareholder [Member]
Treasury Shares [Line Items]	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'
Total shares	3,169,000	11,000	10,263,000	8,502,000	3,000,000	3,159,000	0	9,838,000	5,048,000	10,000	11,000	425,000	454,000	0	0	0	3,000,000
Total cost	$150,449	$489	$468,532	$359,513	'	$150,000	$0	$450,000	$225,000	$449	$489	$18,532	$18,413	$0	$0	$0	$116,100
Average price per share	$47.48	$44.12	$45.65	$42.29	'	$47.49	$0	$45.74	$44.57	$45.39	$44.12	$43.65	$40.56	$0	$0	$0	$38.70

NONCONTROLLING_INTEREST_DETAIL

NONCONTROLLING INTEREST (DETAILS) (USD $)	3 Months Ended		9 Months Ended			1 Months Ended	3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Nov. 30, 2013	Sep. 30, 2014	Dec. 31, 2013
						Ventures Re [Member]	Ventures Re [Member]	Ventures Re [Member]
Noncontrolling Interest [Line Items]	'	'	'	'	'	'	'	'
Third party non-voting redeemable preferred share capital	'	'	'	'	'	$50,000,000	'	'
Decrease from return of capital to noncontrolling interests	'	'	-10,000,000	'	'	'	-10,000,000	'
Increase from issuance of preferred equity to noncontrolling interests	'	'	25,000,000	'	'	'	25,000,000	'
Assets	20,965,047,000	'	20,965,047,000	'	19,634,784,000	'	103,000,000	50,000,000
Liabilities	15,084,923,000	'	15,084,923,000	'	13,766,822,000	'	41,000,000	0
Change in Noncontrolling Interest [Roll Forward]	'	'	'	'	'	'	'	'
Balance at January 1, 2014	'	'	50,000,000	'	'	'	'	'
Increase from issuance of preferred equity to noncontrolling interests	'	'	25,000,000	'	'	'	25,000,000	'
Decrease from return of capital to noncontrolling interests	'	'	-10,000,000	'	'	'	-10,000,000	'
Amounts attributable to (from) noncontrolling interests	-6,160,000	0	-3,365,000	0	'	'	'	'
Balance at September 30, 2014	$61,635,000	'	$61,635,000	'	'	'	'	'

DEBT_AND_FINANCING_ARRANGEMENT1

DEBT AND FINANCING ARRANGEMENTS (Details) (USD $)

9 Months Ended

3 Months Ended

9 Months Ended

0 Months Ended

0 Months Ended

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Mar. 13, 2014

Sep. 30, 2014

Mar. 13, 2014

Sep. 30, 2014

Sep. 30, 2014

AXIS Specialty Finance PLC [Member]

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

2014 AXIS Specialty Finance PLC Senior Notes Due 2019 [Member]

2014 AXIS Specialty Finance PLC Senior Notes Due 2019 [Member]

2014 AXIS Specialty Finance PLC Senior Notes Due 2045 [Member]

2014 AXIS Specialty Finance PLC Senior Notes Due 2045 [Member]

2004 AXIS Capital Holdings Limited Senior Notes [Member]

Senior notes [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Face amount

'

'

'

'

'

'

'

'

$250,000,000

'

$250,000,000

$500,000,000

Interest rate

'

'

'

'

'

'

'

'

2.65%

'

5.15%

5.75%

Issue price (percentage of face amount)

'

'

'

'

'

'

'

99.90%

'

99.47%

'

'

Net proceeds on issuance

494,344,000

0

'

'

'

'

'

248,000,000

'

246,000,000

'

'

Percentage ownership in subsidiary

'

'

100.00%

'

'

'

'

'

'

'

'

'

Interest Expense

'

'

'

$20,000,000

$15,000,000

$55,000,000

$44,000,000

'

'

'

'

'

DEBT_AND_FINANCING_ARRANGEMENT2

DEBT AND FINANCING ARRANGEMENTS (Details 2) (USD $)	Sep. 30, 2014
In Millions, unless otherwise specified
Letter of Credit Facility [Member]	'
Line of Credit Facility [Line Items]	'
Maximum capacity	$750
Letters of credit outstanding	429
Letter of Credit Facility [Member] | ING [Member]	'
Line of Credit Facility [Line Items]	'
Maximum capacity	0
Credit Facility [Member]	'
Line of Credit Facility [Line Items]	'
Maximum capacity	250
Letters of credit outstanding	0
Credit facility borrowings	$0

COMMITMENTS_AND_CONTINGENCIES_

COMMITMENTS AND CONTINGENCIES (DETAILS) (USD $)	Sep. 30, 2014
In Millions, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'
Outstanding reinsurance purchase commitment	$93

OTHER_COMPREHENSIVE_INCOME_LOS2

OTHER COMPREHENSIVE INCOME (LOSS) (DETAILS) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Before Tax Amount	'	'	'	'
Unrealized gains (losses) arising during the period	($176,278)	$118,821	$37,858	($188,808)
Adjustment for reclassification of net realized investment gains and OTTI losses recognized in net income	-74,306	-8,215	-130,634	-51,166
Unrealized gains (losses) arising during the period, net of reclassification adjustment	-250,584	110,606	-92,776	-239,974
Non-credit portion of OTTI losses	0	0	0	0
Foreign currency translation adjustment	-10,000	3,635	-3,551	-14,892
Total other comprehensive income (loss)	-260,584	114,241	-96,327	-254,866
Tax (Expense) Benefit	'	'	'	'
Unrealized gains (losses) arising during the period	9,218	-8,181	-12,984	18,022
Adjustment for reclassification of net realized investment gains and OTTI losses recognized in net income	1,636	-442	14,421	4,595
Unrealized gains (losses) arising during the period, net of reclassification adjustment	10,854	-8,623	1,437	22,617
Non-credit portion of OTTI losses	0	0	0	0
Foreign currency translation adjustment	0	0	0	0
Total other comprehensive income (loss)	10,854	-8,623	1,437	22,617
Net of Tax Amount	'	'	'	'
Unrealized gains (losses) arising during the period	-167,060	110,640	24,874	-170,786
Adjustment for reclassification of net realized investment gains and OTTI losses recognized in net income	-72,670	-8,657	-116,213	-46,571
Unrealized gains (losses) arising during the period, net of reclassification adjustment	-239,730	101,983	-91,339	-217,357
Non-credit portion of OTTI losses	0	0	0	0
Foreign currency translation adjustment	-10,000	3,635	-3,551	-14,892
Total other comprehensive income (loss), net of tax	($249,730)	$105,618	($94,890)	($232,249)

OTHER_COMPREHENSIVE_INCOME_LOS3

OTHER COMPREHENSIVE INCOME (LOSS) (DETAILS 2) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reclassification out of accumulated comprehensive income into net income available to common shareholders [Line Items]	'	'	'	'
Other realized investment gains (losses)	$86,879	($1,897)	$133,450	$64,840
OTTI losses	-9,431	-2,811	-12,121	-8,836
Income before income taxes	278,868	156,665	643,220	557,416
Income tax expense (benefit)	4,098	-6,030	-9,527	-11,500
Net income attributable to AXIS Capital	289,126	150,635	637,058	545,916
Unrealized appreciation on available for sale investments [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Reclassification out of accumulated comprehensive income into net income available to common shareholders [Line Items]	'	'	'	'
Other realized investment gains (losses)	83,737	11,026	142,755	60,002
OTTI losses	-9,431	-2,811	-12,121	-8,836
Income before income taxes	74,306	8,215	130,634	51,166
Income tax expense (benefit)	-1,636	442	-14,421	-4,595
Net income attributable to AXIS Capital	$72,670	$8,657	$116,213	$46,571