Validus 10-Q 2 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 30, 2014
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'VALIDUS HOLDINGS LTD	'
Entity Central Index Key	'0001348259	'
Document Type	'10-Q	'
Document Period End Date	31-Mar-14	'
Amendment Flag	'false	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Current Fiscal Year End Date	'--12-31	'
Entity Well-known Seasoned Issuer	'Yes	'
Entity Voluntary Filers	'No	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	90,786,820

Consolidated_Balance_Sheets_Un

Consolidated Balance Sheets (Unaudited) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets	'	'
Fixed maturities, at fair value (amortized cost: 2014—$5,263,024; 2013—$5,522,853)	$5,287,600	$5,542,258
Short-term investments, at fair value (amortized cost: 2014—$831,679; 2013—$751,734)	831,800	751,778
Other investments, at fair value (cost: 2014—$632,924; 2013—$637,728)	662,974	618,316
Cash and cash equivalents	1,017,350	1,056,346
Total investments and cash	7,799,724	7,968,698
Investments in affiliates	221,607	141,243
Premiums receivable	1,091,391	697,233
Deferred acquisition costs	202,367	134,269
Prepaid reinsurance premiums	218,363	103,251
Securities lending collateral	4,877	3,392
Loss reserves recoverable	348,407	370,154
Paid losses recoverable	37,032	80,080
Intangible assets	105,367	106,407
Goodwill	20,393	20,393
Accrued investment income	16,518	18,876
Other assets	190,043	202,436
Total assets	10,256,089	9,846,432
Liabilities	'	'
Reserve for losses and loss expenses	2,925,059	3,030,399
Unearned premiums	1,273,734	824,496
Reinsurance balances payable	212,807	154,874
Securities lending payable	5,343	3,858
Deferred income taxes	22,609	19,086
Net payable for investments purchased	84,303	19,383
Accounts payable and accrued expenses	183,794	278,187
Notes payable to operating affiliates	561,373	439,272
Senior notes payable	247,225	247,198
Debentures payable	541,454	541,416
Total liabilities	6,057,701	5,558,169
Commitments and contingent liabilities	'	'
Redeemable noncontrolling interest	8,390	86,512
Shareholders' equity	'	'
Common shares, 571,428,571 authorized, par value $0.175 (Issued: 2014—154,597,094; 2013—154,488,497; Outstanding: 2014—90,786,237; 2013—96,044,312)	27,055	27,036
Treasury shares (2014—63,810,857; 2013—58,444,185)	-11,167	-10,228
Additional paid-in-capital	1,490,652	1,677,894
Accumulated other comprehensive (loss)	-155	-617
Retained earnings	2,142,679	2,010,009
Total shareholders' equity available to Validus	3,649,064	3,704,094
Noncontrolling interest	540,934	497,657
Total shareholders' equity	4,189,998	4,201,751
Total liabilities, noncontrolling interests and shareholders’ equity	$10,256,089	$9,846,432

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Assets	'	'
Fixed maturities, at amortized cost or cost	$5,263,024	$5,522,853
Short-term investments, at amortized cost or cost	831,679	751,734
Other investments, at amortized cost or cost	$632,924	$637,728
Shareholders' equity	'	'
Common shares, shares authorized	571,428,571	571,428,571
Common shares, par value	$0.18	$0.18
Common shares, shares issued	154,597,094	154,488,497
Common shares, shares outstanding	90,786,237	96,044,312
Treasury stock, common shares	63,810,857	58,444,185,000

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Noncontrolling Interest and Redeemable Noncontrolling Interest	$549,324	$487,421
Issuance of shares	'	55,690
Revenues	'	'
Gross premiums written	1,011,991	1,104,760
Reinsurance premiums ceded	-194,908	-187,216
Net premiums written	817,083	917,544
Change in unearned premiums	-334,126	-386,483
Net premiums earned	482,957	531,061
Net investment income	23,362	25,649
Net realized gains on investments	3,740	1,721
Change in net unrealized gains (losses) on investments	55,693	-7,237
Income from investment affiliate	5,348	1,477
Other income	13,830	2,685
Foreign exchange (losses) gains	-6,478	6,922
Total revenues	578,452	562,278
Expenses	'	'
Losses and loss expenses	162,671	144,771
Policy acquisition costs	85,649	93,611
General and administrative expenses	74,445	80,279
Share compensation expenses	7,147	2,318
Finance expenses	15,900	14,369
Total expenses	345,812	335,348
Income before taxes, income from operating affiliates and (income) attributable to operating affiliate investors	232,640	226,930
Tax benefit	40	318
Income from operating affiliates	4,927	3,523
(Income) attributable to operating affiliate investors	-31,710	-10,077
Net income	205,897	220,694
Net (income) loss attributable to noncontrolling interest	-43,509	2,549
Net income available to Validus	162,388	223,243
Other comprehensive income (loss)	'	'
Foreign currency translation adjustments	462	-9,785
Other comprehensive income (loss)	462	-9,785
Comprehensive income available to Validus	$162,850	$213,458
Weighted average number of common shares and common share equivalents outstanding	'	'
Basic	93,451,999	107,386,438
Diluted	97,799,519	110,052,999
Basic earnings per share available to common shareholders	$1.72	$1.94
Earnings per diluted share available to common shareholders	$1.66	$1.90
Cash dividends declared per share	$0.30	$2.30

Consolidated_Statements_of_Sha

Consolidated Statements of Shareholders' Equity (Unaudited) (USD $)	Total	Common shares	Treasury shares	Additional paid-in capital	Accumulated other comprehensive (loss)	Retained earnings
In Thousands
Balance - Beginning of period at Dec. 31, 2012	'	$26,722	($7,836)	$2,160,478	($2,953)	$1,844,416
Common shares issued, net	'	47	'	3,074	'	'
Repurchase of common shares	'	'	-333	-69,358	'	'
Share compensation expenses	'	'	'	2,318	'	'
Other comprehensive income (loss)	-9,785	'	'	'	-9,785	'
Dividends	'	'	'	'	'	-266,143
Net income	220,694	'	'	'	'	220,694
Net (income) loss attributable to noncontrolling interest	2,549	'	'	'	'	2,549
Noncontrolling interest	431,144	'	'	'	'	'
Total shareholders' equity at Mar. 31, 2013	4,335,034	'	'	'	'	'
Balance - End of period at Mar. 31, 2013	3,903,890	26,769	-8,169	2,096,512	-12,738	1,801,516
Balance - Beginning of period at Dec. 31, 2013	3,704,094	27,036	-10,228	1,677,894	-617	2,010,009
Common shares issued, net	'	19	'	2,011	'	'
Repurchase of common shares	'	'	-939	-196,400	'	'
Share compensation expenses	'	'	'	7,147	'	'
Other comprehensive income (loss)	462	'	'	'	462	'
Dividends	'	'	'	'	'	-29,718
Net income	205,897	'	'	'	'	205,897
Net (income) loss attributable to noncontrolling interest	-43,509	'	'	'	'	-43,509
Noncontrolling interest	540,934	'	'	'	'	'
Total shareholders' equity at Mar. 31, 2014	4,189,998	'	'	'	'	'
Balance - End of period at Mar. 31, 2014	$3,649,064	$27,055	($11,167)	$1,490,652	($155)	$2,142,679

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Cash flows provided by (used in) operating activities	'	'
Net income	$205,897	$220,694
Adjustments to reconcile net income to cash provided by (used in) operating activities:	'	'
Share compensation expenses	7,147	2,318
Gain on deconsolidation of subsidiary	-1,372	0
Amortization of discount on senior notes	27	27
Income from investment affiliate	-5,348	-1,477
Net realized gains on investments	-3,740	-1,721
Change in net unrealized (gains) losses on investments	-55,693	7,237
Amortization of intangible assets	1,040	1,040
Income from operating affiliates	-4,927	-3,523
Foreign exchange (gains) losses included in net income	-4,347	18,906
Amortization of premium on fixed maturities	4,117	5,059
Change in:	'	'
Premiums receivable	-393,543	-400,153
Deferred acquisition costs	-68,098	-72,916
Prepaid reinsurance premiums	-115,112	-100,984
Loss reserves recoverable	21,832	6,447
Paid losses recoverable	43,054	30,438
Income taxes recoverable	0	-2,132
Accrued investment income	2,366	1,532
Other assets	13,558	8,020
Reserve for losses and loss expenses	-105,842	-138,633
Unearned premiums	449,238	487,467
Reinsurance balances payable	57,765	51,300
Deferred income taxes	3,551	1,250
Accounts payable and accrued expenses	-95,997	-40,113
Net cash (used in) provided by operating activities	-44,427	80,083
Cash flows provided by (used in) investing activities	'	'
Proceeds on sales of investments	1,086,527	1,410,509
Proceeds on maturities of investments	124,716	125,841
Purchases of fixed maturities	-884,461	-2,140,447
(Purchases) sales of short-term investments, net	-107,411	744,518
Sales of other investments	3,539	31,121
Increase in securities lending collateral	-1,485	-1,689
Redemption of investment in operating affiliates	43,366	50,222
Purchase of investment in investment affiliate	0	-1,341
Net cash provided by investing activities	264,791	218,734
Cash flows provided by (used in) financing activities	'	'
Net (repayment of) proceeds on issuance of notes payable to operating affiliates	-30,600	175,637
Issuance of common shares, net	2,030	3,121
Purchases of common shares under share repurchase program	-197,339	-69,691
Dividends paid	-29,330	-262,232
Increase in securities lending payable	1,485	1,689
(Redemption of) investment in third party redeemable noncontrolling interest	-10,496	36,290
Net cash (used in) financing activities	-264,250	-115,186
Effect of foreign currency rate changes on cash and cash equivalents	4,890	-33,786
Net (decrease) increase in cash	-38,996	149,845
Cash and cash equivalents - beginning of period	1,056,346	1,219,379
Cash and cash equivalents - end of period	1,017,350	1,369,224
Taxes paid during the period	175	693
Interest paid during the period	$19,174	$17,819

Basis_of_preparation_and_conso

Basis of preparation and consolidation	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of presentation and consolidation	'
	Basis of preparation and consolidation
	These unaudited Consolidated Financial Statements include Validus Holdings, Ltd. and its wholly and majority owned subsidiaries (together the "Company") and have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 in Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In addition, the year-end balance sheet data was derived from audited financial statements but does not include all disclosures required by U.S. GAAP. This Quarterly Report on Form 10-Q should be read in conjunction with the financial statements and related notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2013, as filed with the U.S. Securities and Exchange Commission (the "SEC").
	In the opinion of management, these unaudited consolidated financial statements reflect all adjustments (including normal recurring adjustments) considered necessary for a fair presentation of the Company's financial position and results of operations as at the end of and for the periods presented. To facilitate comparison of information, certain amounts in prior periods have been reclassified to conform to current period presentation. The consolidated statement of cash flows for the three months ended March 31, 2013 includes a reclassification of $19,400 from cash flows used in financing activities to cash flows provided by operating activities to revise the presentation of subscriptions received in advance from third party investors. For the three months ended March 31, 2013, $10,077 within finance expenses has been reclassified into income attributable to operating affiliate investors to conform to current period presentation. All significant intercompany accounts and transactions have been eliminated. The results of operations for any interim period are not necessarily indicative of the results for a full year.
	The preparation of these financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. While management believes that the amounts included in the Consolidated Financial Statements reflect its best estimates and assumptions, actual results could differ materially from those estimates. The Company’s principal estimates include:
	•reserve for losses and loss expenses;
	•premium estimates for business written on a line slip or proportional basis;
	•the valuation of goodwill and intangible assets;
	•reinsurance recoverable balances including the provision for uncollectible amounts; and
	•investment valuation of financial assets.
	The term “ASC” used in these notes refers to Accounting Standard Codification issued by the U.S. Financial Accounting Standards Board (“FASB”).

Recent_accounting_pronouncemen

Recent accounting pronouncements	3 Months Ended
	Mar. 31, 2014
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]	'
Recent accounting pronouncements	'
	Recent accounting pronouncements
	Adoption of New Accounting Standards
	Parent’s Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity
	In March 2013, the FASB issued Accounting Standard Update No. 2013-05, “Parent’s Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity” (ASU 2013-05). The objective of this Update is to resolve the diversity in practice about whether Subtopic 810-10, Consolidation-Overall, or Subtopic 830-30, Foreign Currency Matters-Translation of Financial Statements, applies to the release of the cumulative translation adjustment into net income when a parent either sells a part or all of its investment in a foreign entity or no longer holds a controlling financial interest in a subsidiary within a foreign entity. The amendments became effective for the Company on January 1, 2014. Adoption of this guidance did not have a material impact on the Company’s Consolidated Financial Statements.
	Financial Services - Investment Companies - Amendments to the Scope, Measurement, and Disclosure Requirements
	In June 2013, the FASB issued Accounting Standard Update No. 2013-08, “Financial Services - Investment Companies - Amendments to the Scope, Measurement, and Disclosure Requirements” (ASU 2013-08). The amendments in this Update change the assessment of whether an entity is an investment company by developing a new two-tiered approach for that assessment, which requires an entity to possess certain fundamental characteristics while allowing judgment in assessing other typical characteristics. The new approach requires an entity to assess all of the characteristics of an investment company and consider its purpose and determine whether it is an investment company. The amendments became effective for the Company on January 1, 2014. The Company performed an assessment and has concluded that the AlphaCat ILS funds meet the characteristics outlined in this Update and therefore will continue to be treated as investment companies.
	Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists
	In July 2013, the FASB issued Accounting Standard Update No. 2013-11 “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists” (ASU 2013-11). This Update applies to all entities that have unrecognized tax benefits when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists at the reporting date. An unrecognized tax benefit should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward. To the extent a net operating loss carryforward is not available to settle any additional income taxes that would result from the disallowance of a tax position at the reporting date, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. The amendments became effective for the Company on January 1, 2014. Adoption of this guidance did not have a material impact on the Company’s Consolidated Financial Statements.

Investments

Investments	3 Months Ended
	Mar. 31, 2014
Investments [Abstract]	'
Investments	'
	Investments
	(a)	Fixed maturity, short-term and other investments
	The Company's investments in fixed maturities, short-term investments and other investments are classified as trading and carried at fair value, with related changes in net unrealized gains or losses included in earnings.
	The amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments at March 31, 2014 were as follows:
		Amortized Cost or Cost			Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
	U.S. government and government agency	$	1,122,846		$	2,241			$	(4,232	)		$	1,120,855
	Non-U.S. government and government agency	438,415			5,138				(1,224		)		442,329
	U.S. states, municipalities and political subdivisions	43,960			626				(122		)		44,464
	Agency residential mortgage-backed securities	293,013			8,201				(1,653		)		299,561
	Non-agency residential mortgage-backed securities	16,721			254				(645		)		16,330
	U.S. corporate	1,331,550			9,315				(3,455		)		1,337,410
	Non-U.S. corporate	699,404			6,460				(1,973		)		703,891
	Bank loans	640,672			4,678				(1,649		)		643,701
	Catastrophe bonds	30,500			1,747				—				32,247
	Asset-backed securities	623,631			1,408				(540		)		624,499
	Commercial mortgage-backed securities	22,312			7				(6		)		22,313
	Total fixed maturities	5,263,024			40,075				(15,499		)		5,287,600
	Total short-term investments	831,679			121				—				831,800
	Other investments
	Fund of hedge funds	2,977			138				(921		)		2,194
	Hedge funds (a)	581,369			110,058				(84,965		)		606,462
	Private equity investments	12,068			2,562				(668		)		13,962
	Investment funds	30,311			188				—				30,499
	Mutual funds	6,199			3,658				—				9,857
	Total other investments	632,924			116,604				(86,554		)		662,974
	Total investments including noncontrolling interests	$	6,727,627		$	156,800			$	(102,053	)		$	6,782,374
	Noncontrolling interest (a)	$	(512,121	)	$	(95,750	)		$	76,468			$	(531,403	)
	Redeemable noncontrolling interest (b)	$	(1,976	)	$	—			$	—			$	(1,976	)
	Total investments excluding noncontrolling interests	$	6,213,530		$	61,050			$	(25,585	)		$	6,248,995
	(a)	Included in the hedge funds balance are investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.
	(b)	Included in the total investments balance are investments held by one AlphaCat ILS fund which is consolidated by the Company but in which the Company has an equity interest of less than 100%. The remaining interests are held by third party investors and included in the Consolidated Balance Sheets as redeemable noncontrolling interest.
	The amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments at December 31, 2013 were as follows:
		Amortized Cost or Cost			Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
	U.S. government and government agency	$	1,368,826		$	2,589			$	(6,736	)		$	1,364,679
	Non-U.S. government and government agency	454,578			6,511				(2,021		)		459,068
	U.S. states, municipalities and political subdivisions	42,978			459				(317		)		43,120
	Agency residential mortgage-backed securities	305,450			8,310				(2,261		)		311,499
	Non-agency residential mortgage-backed securities	16,530			143				(914		)		15,759
	U.S. corporate	1,328,960			9,208				(5,684		)		1,332,484
	Non-U.S. corporate	711,581			5,917				(3,173		)		714,325
	Bank loans	712,859			5,659				(1,402		)		717,116
	Catastrophe bonds	72,000			2,551				—				74,551
	Asset-backed securities	509,091			1,409				(843		)		509,657
	Total fixed maturities	5,522,853			42,756				(23,351		)		5,542,258
	Total short-term investments	751,734			45				(1		)		751,778
	Other investments
	Fund of hedge funds	3,141			83				(921		)		2,303
	Hedge funds (a)	584,518			71,641				(95,076		)		561,083
	Private equity investments	12,333			1,410				(258		)		13,485
	Investment funds	31,537			92				—				31,629
	Mutual funds	6,199			3,617				—				9,816
	Total other investments	637,728			76,843				(96,255		)		618,316
	Total investments including noncontrolling interests	$	6,912,315		$	119,644			$	(119,607	)		$	6,912,352
	Noncontrolling interest (a)	(512,121		)	(62,850		)		85,569				(489,402		)
	Redeemable noncontrolling interest (b)	$	(18,365	)	$	—			$	—			$	(18,365	)
	Total investments excluding noncontrolling interests	$	6,381,829		$	56,794			$	(34,038	)		$	6,404,585
	(a)	Included in the hedge funds balance are investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.
	(b)	Included in the total investments balance are investments held by two AlphaCat ILS funds which are consolidated by the Company but in which the Company has an equity interest of less than 100%. The remaining interests are held by third party investors and included in the Consolidated Balance Sheets as redeemable noncontrolling interest.
	The following table sets forth certain information regarding the investment ratings of the Company’s fixed maturities portfolio as at March 31, 2014 and December 31, 2013. Investment ratings are the lower of Moody’s or Standard & Poor’s rating for each investment security, presented in Standard & Poor’s equivalent rating. For investments where Moody’s and Standard & Poor’s ratings are not available, Fitch ratings are used and presented in Standard & Poor’s equivalent rating.
		March 31, 2014						December 31, 2013
		Estimated Fair Value			% of Total			Estimated Fair Value				% of Total
	AAA	$	906,648		17.1	%		$	788,490			14.2	%
	AA	2,124,629			40.2	%		2,378,491				42.9	%
A	1,178,357			22.3	%		1,174,562				21.2	%
BBB	397,563			7.5	%		420,559				7.6	%
Total investment-grade fixed maturities	4,607,197			87.1	%		4,762,102				85.9	%
BB	336,265			6.4	%		350,678				6.3	%
B	321,128			6.1	%		390,430				7	%
CCC	4,247			0.1	%		4,659				0.1	%
CC	2,602			—	%		2,731				0.1	%
D/NR	16,161			0.3	%		31,658				0.6	%
Total non-investment grade fixed maturities	680,403			12.9	%		780,156				14.1	%
Total fixed maturities	$	5,287,600		100	%		$	5,542,258			100	%
The amortized cost and estimated fair value amounts for fixed maturities held at March 31, 2014 and December 31, 2013 are shown below by contractual maturity. Actual maturity may differ from contractual maturity because certain borrowers may have the right to call or prepay certain obligations with or without call or prepayment penalties.
	March 31, 2014							December 31, 2013
	Amortized Cost			Estimated Fair Value				Amortized Cost				Estimated Fair Value
Due in one year or less	$	625,774		$	629,800			$	688,855			$	692,768
Due after one year through five years	3,311,970			3,325,578				3,603,459				3,613,847
Due after five years through ten years	366,524			366,409				396,389				395,633
Due after ten years	3,079			3,110				3,079				3,095
	4,307,347			4,324,897				4,691,782				4,705,343
Asset-backed and mortgage-backed securities	955,677			962,703				831,071				836,915
Total fixed maturities	$	5,263,024		$	5,287,600			$	5,522,853			$	5,542,258
(b)	Net investment income
Net investment income was derived from the following sources:
	Three Months Ended
	March 31, 2014			March 31, 2013
Fixed maturities and short-term investments	$	23,297		$	27,531
Cash and cash equivalents	1,957			533
Securities lending income	2			—
Total gross investment income	25,256			28,064
Investment expenses	(1,894		)	(2,415		)
Total net investment income	$	23,362		$	25,649
(c)	Net realized gains and change in net unrealized gains (losses) on investments
The following represents an analysis of net realized gains and the change in net unrealized gains (losses) on investments:
	Three Months Ended
	March 31, 2014			March 31, 2013
Fixed maturities, short-term and other investments and cash equivalents
Gross realized gains	$	5,296		$	10,720
Gross realized (losses)	(1,556		)	(8,999		)
Net realized gains on investments	3,740			1,721
Change in net unrealized gains (losses) on investments (a)	55,693			(7,237		)
Total net realized gains and change in net unrealized gains (losses) on investments including noncontrolling interest	59,433			(5,516		)
Noncontrolling interest (a)	(42,002		)	4,651
Total net realized gains and change in net unrealized gains (losses) on investments excluding noncontrolling interest	$	17,431		$	(865	)
(a)	Includes change in net unrealized (gains) losses on investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and is included in the Consolidated Statements of Comprehensive Income as net (income) loss attributable to noncontrolling interest.
(d)	Pledged investments
The following tables outline investments pledged as collateral under the Company's credit facilities. For further details on the credit facilities, please refer to Note 12: “Debt and financing arrangements.”
		March 31, 2014
Description		Commitment			Issued and Outstanding				Investments and cash pledged as collateral
$400,000 syndicated unsecured letter of credit facility		$	400,000		$	—			$	—
$525,000 syndicated secured letter of credit facility		525,000			309,422				499,905
$200,000 secured bi-lateral letter of credit facility		200,000			18,676				35,225
Talbot FAL facility		25,000			25,000				30,897
PaCRe senior secured letter of credit facility		10,000			294				—
AlphaCat Re secured letter of credit facility		30,000			24,800				30,022
IPC bi-lateral facility		40,000			19,817				96,960
$375,000 Flagstone bi-lateral facility		375,000			292,532				453,943
		$	1,605,000		$	690,541			$	1,146,952
		December 31, 2013
Description		Commitment			Issued and Outstanding				Investments and cash pledged as collateral
$400,000 syndicated unsecured letter of credit facility		$	400,000		$	—			$	—
$525,000 syndicated secured letter of credit facility		525,000			358,567				507,620
$200,000 secured bi-lateral letter of credit facility		200,000			16,726				130,256
Talbot FAL facility		25,000			25,000				30,801
PaCRe senior secured letter of credit facility		10,000			294				—
AlphaCat Re secured letter of credit facility		24,800			24,800				24,806
IPC bi-lateral facility		40,000			20,177				98,465
$375,000 Flagstone bi-lateral facility		375,000			305,686				454,458
		$	1,599,800		$	751,250			$	1,246,406
In addition, $2,889,470 of cash and cash equivalents and investments were pledged during the normal course of business as at March 31, 2014 (December 31, 2013: $2,947,475). Of those, $2,884,472 were held in trust (December 31, 2013: $2,942,508). Pledged assets are generally for the benefit of the Company's cedants and policyholders, to support AlphaCat's fully collateralized reinsurance transactions and to facilitate the accreditation of Talbot as an alien insurer/reinsurer by certain regulators. See Note 14 (b) for detail on Talbot's FAL facility.

Fair_value_measurements

Fair value measurements	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair value measurements	'
	Fair value measurements
	(a)	Classification within the fair value hierarchy
	Fair value is defined as the price to sell an asset or transfer a liability in an orderly transaction between market participants. Under U.S. GAAP, a company must determine the appropriate level in the fair value hierarchy for each fair value measurement. The fair value hierarchy prioritizes the inputs, which refer broadly to assumptions market participants would use in pricing an asset or liability, into three levels. It gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The level in the fair value hierarchy within which a fair value measurement in its entirety falls is determined based on the lowest level input that is significant to the fair value measurement in its entirety.
	The three levels of the fair value hierarchy are described below:
	Level 1 - Fair values are measured based on unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access.
	Level 2 - Fair values are measured 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 - Fair values are measured based on inputs that are unobservable and significant to the overall fair value measurement. The unobservable inputs reflect our own judgments about assumptions where there is little, if any, market activity for that asset or liability 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 instrument. 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 (for example, from market to cash flow approach) or may cause us to use multiple valuation techniques to estimate the fair value of a financial instrument. These circumstances could cause an instrument to be reclassified between levels within the fair value hierarchy.
	There have been no material changes in the Company's valuation techniques during the period, or periods, represented by these Consolidated Financial Statements. The following methods and assumptions were used in estimating the fair value of each class of financial instrument recorded in the Consolidated Balance Sheets.
	At March 31, 2014, the Company’s investments were allocated between Levels 1, 2 and 3 as follows:
		Level 1				Level 2				Level 3			Total
	U.S. government and government agency	$	—			$	1,120,855			$	—		$	1,120,855
	Non-U.S. government and government agency	—				442,329				—			442,329
	U.S. states, municipalities and political subdivisions	—				44,464				—			44,464
	Agency residential mortgage-backed securities	—				299,561				—			299,561
	Non-agency residential mortgage-backed securities	—				16,330				—			16,330
	U.S. corporate	—				1,337,410				—			1,337,410
	Non-U.S. corporate	—				703,891				—			703,891
	Bank loans	—				643,701				—			643,701
	Catastrophe bonds	—				25,544				6,703			32,247
	Asset-backed securities	—				624,499				—			624,499
	Commercial mortgage-backed securities	—				22,313				—			22,313
	Total fixed maturities	—				5,280,897				6,703			5,287,600
	Total short-term investments	817,937				13,863				—			831,800
	Other investments
	Fund of hedge funds	—				—				2,194			2,194
	Hedge funds (a)	—				—				606,462			606,462
	Private equity investments	—				—				13,962			13,962
	Investment fund	—				30,499				—			30,499
	Mutual funds	—				9,857				—			9,857
	Total other investments	—				40,356				622,618			662,974
	Total investments including noncontrolling interests	$	817,937			$	5,335,116			$	629,321		$	6,782,374
	Noncontrolling interest (a)	$	—			$	—			$	(531,403	)	$	(531,403	)
	Redeemable noncontrolling interest (b)	$	(1,976	)		$	—			$	—		$	(1,976	)
	Total investments excluding noncontrolling interests	$	815,961			$	5,335,116			$	97,918		$	6,248,995
	(a)	Included in the hedge funds balance are investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.
	(b)	Included in the total investments balance are investments held by one AlphaCat ILS fund which is consolidated by the Company but in which the Company has an equity interest of less than 100%. The remaining interests are held by third party investors and included in the Consolidated Balance Sheets as redeemable noncontrolling interest.
	At December 31, 2013, the Company’s investments were allocated between Levels 1, 2 and 3 as follows:
		Level 1				Level 2				Level 3			Total
	U.S. government and government agency	$	—			$	1,364,679			$	—		$	1,364,679
	Non-U.S. government and government agency	—				459,068				—			459,068
	U.S. states, municipalities and political subdivisions	—				43,120				—			43,120
	Agency residential mortgage-backed securities	—				311,499				—			311,499
	Non-agency residential mortgage-backed securities	—				15,759				—			15,759
	U.S. corporate	—				1,332,484				—			1,332,484
	Non-U.S. corporate	—				714,325				—			714,325
	Bank loans	—				717,116				—			717,116
	Catastrophe bonds	—				74,551				—			74,551
	Asset-backed securities	—				509,657				—			509,657
	Total fixed maturities	—				5,542,258				—			5,542,258
	Total short-term investments	747,215				4,563				—			751,778
	Other investments
	Fund of hedge funds	—				—				2,303			2,303
	Hedge funds (a)	—				—				561,083			561,083
	Private equity investments	—				—				13,485			13,485
	Investment fund	—				31,629				—			31,629
	Mutual funds	—				9,816				—			9,816
	Total other investments	—				41,445				576,871			618,316
	Total investments including noncontrolling interests	$	747,215			$	5,588,266			$	576,871		$	6,912,352
	Noncontrolling interest (a)	$	—			$	—			$	(489,402	)	$	(489,402	)
	Redeemable noncontrolling interest (b)	$	(18,365	)		$	—			$	—		$	(18,365	)
	Total investments excluding noncontrolling interests	$	728,850			$	5,588,266			$	87,469		$	6,404,585
(a)	Included in the hedge funds balance are investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.
(b)	Included in the total investments balance are investments held by two AlphaCat ILS funds which are consolidated by the Company but in which the Company has an equity interest of less than 100%. The remaining interests are held by third party investors and included in the Consolidated Balance Sheets as redeemable noncontrolling interest.
At March 31, 2014, Level 3 investments excluding the noncontrolling interest totaled $97,918 (December 31, 2013: $87,469), representing 1.6% (December 31, 2013: 1.4%) of total investments, excluding noncontrolling interest, measured at fair value on a recurring basis.
(b)	Level 1 assets measured at fair value
Short term investments
Short term investments categorized as Level 1 consist primarily of highly liquid securities, all with maturities less than one year from the date of purchase. The fair value of the Company's portfolio of short term investments are generally determined using amortized cost which approximates fair value. The Company has determined that certain of its short-term investments, held in highly liquid money market-type funds, should be included in Level 1 as their fair values are based on quoted market prices in active markets.
(c)	Level 2 assets measured at fair value
Fixed maturity investments
Fixed maturity investments included in Level 2 include U.S. government and government agency, non-U.S. government and government agency, U.S. states, municipalities and political subdivisions, agency residential mortgage-backed securities, non-agency residential mortgage-backed securities, U.S. corporate, non-U.S. corporate, bank loans, catastrophe bonds, asset-backed securities and commercial mortgage-backed securities.
In general, valuation of the Company's fixed maturity investment portfolios is provided by pricing services, such as index providers and pricing vendors, as well as broker quotations. The pricing vendors provide valuations for a high volume of liquid securities that are actively traded. For securities that do not trade on an exchange, the pricing services generally utilize market data and other observable inputs in matrix pricing models to determine month end prices. Prices are generally verified using third party data. Securities which are priced by an index provider are generally included in the index.
In general, broker-dealers value securities through their trading desks based on observable inputs. The methodologies include mapping securities based on trade data, bids or offers, observed spreads, and performance on newly issued securities. Broker-dealers also determine valuations by observing secondary trading of similar securities. Prices obtained from broker quotations are considered non-binding, however they are based on observable inputs and by observing secondary trading of similar securities obtained from active, non-distressed markets.
The Company considers these Level 2 inputs as they are corroborated with other market observable inputs. The techniques generally used to determine the fair value of the Company's fixed maturity investments are detailed below by asset class.
U.S. government and government agency
U.S. government and government agency securities consist primarily of debt securities issued by the U.S. Treasury and mortgage pass-through agencies such as the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation and the Government National Mortgage Association. Fixed maturity investments included in U.S. government and government agency securities are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources and integrate other observations from markets and sector news. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The fair value of each security is individually computed using analytical models which incorporate option adjusted spreads and other daily interest rate data.
Non-U.S. government and government agency
Non-U.S. government and government agency securities consist of debt securities issued by non-U.S. governments and their agencies along with supranational organizations (also known as sovereign debt securities). Securities held in these sectors are primarily priced by pricing services who employ proprietary discounted cash flow models to value the securities. Key quantitative inputs for these models are daily observed benchmark curves for treasury, swap and high issuance credits. The pricing services then apply a credit spread for each security which is developed by in-depth and real time market analysis. For securities in which trade volume is low, the pricing services utilize data from more frequently traded securities with similar attributes. These models may also be supplemented by daily market and credit research for international markets.
U.S. states, municipalities and political subdivisions
The Company's U.S. states, municipalities and political subdivisions portfolio contains debt securities issued by U.S. domiciled state and municipal entities. These securities are generally priced by independent pricing services using the techniques described for U.S. government and government agency securities described above.
Agency residential mortgage-backed securities
The Company's agency residential mortgage-backed investments are primarily priced by pricing services using a mortgage pool specific model which utilizes daily inputs from the active to be announced ("TBA") market which is very liquid, as well as the U.S. treasury market. The model also utilizes additional information, such as the weighted average maturity, weighted average coupon and other available pool level data which is provided by the sponsoring agency. Valuations are also corroborated with daily active market quotes.
Non-agency residential mortgage-backed securities
The Company's non-agency mortgage-backed investments include non-agency prime residential mortgage-backed fixed maturity investments. The Company has no fixed maturity investments classified as sub-prime held in its fixed maturity investments portfolio. Securities held in these sectors are primarily priced by pricing services using an option adjusted spread model or other relevant models, which principally utilize inputs including benchmark yields, available trade information or broker quotes, and issuer spreads. The pricing services also review collateral prepayment speeds, loss severity and delinquencies among other collateral performance indicators for the securities valuation, when applicable.
U.S. corporate
Corporate debt securities consist primarily of investment-grade debt of a wide variety of U.S. corporate issuers and industries. The Company's corporate fixed maturity investments are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources regarding the issuer of the security and obtain credit data, as well as other observations, from markets and sector news. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The pricing services also consider the specific terms and conditions of the securities, including any specific features which may influence risk. In certain instances, securities are individually evaluated using a spread which is added to the U.S. treasury curve or a security specific swap curve as appropriate.
Non-U.S. corporate
Non-U.S. corporate debt securities consist primarily of investment-grade debt of a wide variety of non-U.S. corporate issuers and industries. The Company's non-U.S. corporate fixed maturity investments are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources regarding the issuer of the security and obtain credit data, as well as other observations, from markets and sector news. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The pricing services also consider the specific terms and conditions of the securities, including any specific features which may influence risk.
Bank loans
The Company's bank loan investments consist primarily of below-investment-grade debt of a wide variety of corporate issuers and industries. The Company's bank loans are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources regarding the issuer of the security and obtain credit data, as well as other observations, from markets and sector news. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The pricing services also consider the specific terms and conditions of the securities, including any specific features which may influence risk.
Catastrophe bonds
Catastrophe bonds are based on broker or underwriter bid indications.
Asset-backed securities
Asset backed securities include mostly investment-grade debt securities backed by pools of loans with a variety of underlying collateral, including automobile loan receivables, student loans, credit card receivables, and collateralized loan obligations originated by a variety of financial institutions. Securities held in these sectors are primarily priced by pricing services. The pricing services apply dealer quotes and other available trade information such as bids and offers, prepayment speeds which may be adjusted for the underlying collateral or current price data, the U.S. treasury curve and swap curve as well as cash settlement. The pricing services determine the expected cash flows for each security held in this sector using historical prepayment and default projections for the underlying collateral and current market data. In addition, a spread is applied to the relevant benchmark and used to discount the cash flows noted above to determine the fair value of the securities held in this sector.
Commercial mortgage-backed securities
Commercial mortgage backed securities are investment-grade debt primarily priced by pricing services. The pricing services apply dealer quotes and other available trade information such as bids and offers, prepayment speeds which may be adjusted for the underlying collateral or current price data, the U.S. treasury curve and swap curve as well as cash settlement. The pricing services determine the expected cash flows for each security held in this sector using historical prepayment and default projections for the underlying collateral and current market data. In addition, a spread is applied to the relevant benchmark and used to discount the cash flows noted above to determine the fair value of the securities held in this sector.
Short term investments
Short term investments consist primarily of highly liquid securities, all with maturities less than one year from the date of purchase. The fair value of the Company's portfolio of short term investments is generally determined using amortized cost which approximates fair value. The Company has determined that, other than highly liquid money market-type funds, the remaining 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.
Investment fund
Investment fund consists of one pooled investment which is invested in fixed income securities with high credit ratings. The investment fund is only open to Lloyd’ trust fund participants. The fair value of units in the investment fund is based on the net asset value of the fund as reported by Lloyd’s Treasury & Investment Management.
Mutual funds
Mutual funds consist of two investment funds which are invested in various quoted investments. The fair value of units in the mutual funds is based on the net asset value of the fund as reported by the fund manager.
(d)	Level 3 assets measured at fair value
Level 3 includes financial instruments that are valued using market approach and income approach valuation techniques. These models incorporate both observable and unobservable inputs. The Company's hedge funds, a fund of hedge funds, private equity investments and certain catastrophe bonds are the only financial instruments in this category as at March 31, 2014. For each respective hedge fund investment, the Company obtains and reviews the valuation methodology used by the fund administrators and investment managers to ensure that the hedge fund investments are following fair value principles consistent with U.S. GAAP in determining the net asset value (“NAV”).
Within the hedge fund industry, 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 and regular evaluation of fund performance against applicable benchmarks.
Fund of hedge funds
The fund of hedge funds includes a side pocket. While a redemption request has been submitted, the timing of receipt of proceeds on the side pocket is unknown. The fund's administrator provides a monthly reported NAV with a one-month delay in its valuation. As a result, the fund administrator's February 28, 2014 NAV was used as a basis for fair value measurement in the Company's March 31, 2014 balance sheet. The fund manager has provided an estimate of the fund NAV at March 31, 2014 based on the estimated performance provided from the underlying funds. To determine the reasonableness of the estimated NAV, the Company compares the one-month delayed fund administrator's NAV to the fund manager's estimated NAV that incorporates relevant valuation sources on a timely basis. Material variances are recorded in the current reporting period while immaterial variances are recorded in the following reporting period. As this valuation technique incorporates both observable and significant unobservable inputs, the fund of hedge funds is classified as a Level 3 asset.
Hedge funds
The hedge funds were valued at $606,462 at March 31, 2014 (December 31, 2013: $561,083). The hedge funds consist of an investment in four Paulson & Co. managed funds (the "Paulson hedge funds") and one investment fund assumed from the Flagstone Acquisition (the "Flagstone investment fund").
The Paulson hedge funds' administrator provides monthly reported NAVs with a one-month delay in its valuation. As a result, the funds' administrator's February 28, 2014 NAV was used as a partial basis for fair value measurement in the Company's March 31, 2014 balance sheet. The fund manager provides an estimate of the NAV at March 31, 2014 based on estimated performance. The Company adjusts fair value to the fund manager's estimated NAV that incorporates relevant valuation sources on a timely basis. To determine the reasonableness of the estimated NAV, the Company assesses the variance between the fund manager's estimated NAV and the fund administrator's NAV. Material variances are recorded in the current reporting period while immaterial variances are recorded in the following reporting period. Historically, our valuation estimates have not materially differed from the subsequent NAVs.
The Flagstone investment fund's administrator provides quarterly NAVs with a three-month delay in valuation. As a result, the December 31, 2013 NAV was used as a basis for fair value measurement in the Company's March 31, 2014 balance sheet.
As these valuation techniques incorporate both observable and significant unobservable inputs, both the Paulson hedge funds and the Flagstone investment fund are classified as Level 3 assets. The Paulson hedge funds are subject to quarterly liquidity.
Private equity investments
Private equity investments consist of investments in three private equity funds assumed from the Flagstone Acquisition. The private equity funds' respective fund administrators provide quarterly or semi-annual NAVs with a three-month or six-month delay in valuation as well as audited NAVs as at December 31. As a result, the December 31, 2013 NAV was used as a basis for the fair value measurement in the Company's March 31, 2014 balance sheet. As this valuation technique incorporates both observable and significant unobservable inputs, the private equity investments are classified as Level 3 assets.
The following table presents a reconciliation of the beginning and ending balances for all investments measured at fair value on a recurring basis using Level 3 inputs during the three months ended March 31, 2014 and 2013:
		Three Months Ended
		31-Mar-14				31-Mar-13
Level 3 investments - Beginning of period		$	576,871			$	556,234
Purchases		—				459
Sales		(3,589		)		(31,334		)
Net realized gains		10				40
Net unrealized gains (losses)		49,326				(1,706		)
Transfers into Level 3		6,703				—
Level 3 investments - End of period		$	629,321			$	523,693
Noncontrolling interest (a)		(531,403		)		(428,087		)
Level 3 investments excluding noncontrolling interest		$	97,918			$	95,606
(a)	Includes Level 3 investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.
There have not been any transfers between Levels 1 and 2 during the three months ended March 31, 2014 or 2013. During the three months ended March 31, 2014 there was a transfer of investments from Level 2 into Level 3 of the fair value hierarchy. This transfer was due to a reassessment of the extent of unobservable inputs used in establishing the fair value of certain catastrophe bonds. There were no transfers into or out of Level 3 during the three months ended March 31, 2013.

Investments_in_affilates

Investments in affilates	3 Months Ended
	Mar. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]	'
Investments in affiliates	'
	Investments in affiliates
	The following table presents the Company's investments in affiliates as at March 31, 2014 and December 31, 2013:
		As at March 31, 2014			As at December 31, 2013
	Investment affiliate	$	39,848		$	34,500
	Operating affiliates	181,759			106,743
	Investments in affiliates	$	221,607		$	141,243
	(a)	Investment affiliate
	Aquiline Financial Services Fund II L.P.
	On December 20, 2011, the Company entered into an Assignment and Assumption Agreement (the "Agreement") with Aquiline Capital Partners LLC, a Delaware limited liability company (the "Assignor") and Aquiline Capital Partners II GP (Offshore) Ltd., a Cayman Islands company limited by shares (the "General Partner") pursuant to which the Company has assumed 100% of the Assignor's interest in Aquiline Financial Services Fund II L.P. (the "Partnership") representing a total capital commitment of $50,000 (the "Commitment"), as a limited partner in the Partnership (the "Transferred Interest"). The Transferred Interest is governed by the terms of an Amended and Restated Exempted Limited Partnership Agreement dated as of July 2, 2010 (the "Limited Partnership Agreement"). Pursuant to the terms of the Limited Partnership Agreement, the Commitment will expire on July 2, 2015.
	The Partnership provides quarterly capital account statements with a three-month delay in its valuation. As a result, the Partnership's December 31, 2013 capital account statement was used as the basis for calculating the Company's share of Partnership income for the period.
	The following table presents a reconciliation of the beginning and ending investment in the Company's investment affiliate balance for the three months ended March 31, 2014 and 2013:
			Three Months Ended
			March 31,			March 31,
			2014			2013
	Investment affiliate, beginning of period		$	34,500		$	15,218
	Capital contributions		—			1,341
	Income from investment affiliate		5,348			1,477
	Investment affiliate, end of period		$	39,848		$	18,036
	The following table presents the Company's investment in the Partnership as at March 31, 2014:
		Investment in investment affiliate
		Investment at cost			Voting ownership %			Equity Ownership			Carrying Value
	Aquiline Financial Services Fund II L.P.	$	32,110		—	%		6.7	%		$	39,848
	The following table presents the Company's investment in the Partnership as at December 31, 2013:
		Investment in investment affiliate
		Investment at cost			Voting ownership %			Equity Ownership			Carrying Value
	Aquiline Financial Services Fund II L.P.	$	32,110		—	%		6.7	%		$	34,500
	(b)	Operating affiliates
	AlphaCat Re 2011 Ltd.
	On May 25, 2011, the Company joined with other investors in capitalizing AlphaCat Re 2011 Ltd. ("AlphaCat Re 2011"), a special purpose reinsurer formed for the purpose of writing collateralized reinsurance and retrocessional reinsurance. AlphaCat Re 2011 was a market facing entity and the Company's investment in AlphaCat Re 2011 has been treated as an equity method investment.
	AlphaCat Re 2011 is now considered "off-risk" as the risk periods for all reinsurance contracts written have expired. As a result, partial returns of investment have been made to the investors of AlphaCat Re 2011.The Company's portion of the returns made during the three months ended March 31, 2014 and 2013 are included in the tables below.
	AlphaCat Re 2012 Ltd.
	On May 29, 2012, the Company joined with other investors in capitalizing AlphaCat Re 2012 Ltd. ("AlphaCat Re 2012"), a special purpose reinsurer formed for the purpose of writing collateralized reinsurance with a particular focus on windstorm risks for Florida domiciled insurance companies. AlphaCat Re 2012 was a market facing entity and the Company's investment in AlphaCat Re 2012 has been treated as an equity method investment.
	AlphaCat Re 2012 is now considered "off-risk" as the risk periods for all reinsurance contracts written have expired. As a result, partial returns of investment have been made to the investors of AlphaCat Re 2012.The Company's portion of the returns made during the three months ended March 31, 2014 and 2013 are included in the tables below.
	AlphaCat 2013, Ltd.
	On December 17, 2012, the Company joined with other investors in capitalizing AlphaCat 2013, Ltd. ("AlphaCat 2013"), an entity formed for the purpose of investing in collateralized reinsurance and retrocession on a worldwide basis. AlphaCat 2013 deployed its capital through transactions entered into by AlphaCat Reinsurance Ltd. (“AlphaCat Re”) and the Company's investment in AlphaCat 2013 has been treated as an equity method investment.
	Partial returns of investment have been made to the investors of AlphaCat 2013.The Company's portion of the returns made during the three months ended March 31, 2014 are included in the tables below.
	AlphaCat 2014, Ltd.
	On December 20, 2013, the Company joined with other investors in capitalizing AlphaCat 2014, Ltd. (“AlphaCat 2014”), an entity formed for the purpose of investing in collateralized reinsurance and retrocessional contracts for the January 1, 2014 renewal season. AlphaCat 2014 deploys its capital through transactions entered into by AlphaCat Re and the Company's investment in AlphaCat 2014 has been treated as an equity method investment.
	AlphaCat ILS funds
	The AlphaCat ILS funds invest in instruments with returns linked to property catastrophe reinsurance, retrocession and insurance linked securities ("ILS") contracts. AlphaCat ILS funds all deploy their capital through the AlphaCat Master Fund Ltd. (the “Master Fund”) and AlphaCat Re. All three funds are variable interest entities, with one being consolidated by the Company as the primary beneficiary and one being accounted for as an equity method investment since the Company holds an equity interest of 9.1%. The third fund had been consolidated by the Company as the primary beneficiary from its formation through to December 31, 2013. However, on January 1, 2014 the fund received $35,000 in additional third party subscriptions, resulting in a reduction of the Company’s equity interest below 50%. Since the Company retains significant influence, this fund has been deconsolidated and accounted for as an equity method investment from January 1, 2014. The fair value of the retained interest, based on the fair value of the underlying instruments in Master Fund and AlphaCat Re, amounted to $113,455 at January 1, 2014. The deconsolidation resulted in a gain of $1,372 and is included in the Consolidated Statements of Comprehensive Income as other income. The Company's maximum exposure to any of the funds is the amount of capital invested at any given time.
	AlphaCat Master Fund Ltd. and AlphaCat Reinsurance Ltd.
	The Company utilizes Master Fund and AlphaCat Re for the purpose of investing in capital market products and writing collateralized reinsurance, respectively, on behalf of certain entities within the AlphaCat operating segment. Master Fund and AlphaCat Re are market facing entities which enter into transactions on behalf of AlphaCat 2013, AlphaCat 2014 and the AlphaCat ILS funds. The Company owns all of the voting equity interest in Master Fund and AlphaCat Re and, as a result, their financial statements are included in the Consolidated Financial Statements of the Company.
	The following tables present a reconciliation of the beginning and ending investment in operating affiliates for the three months ended March 31, 2014 and 2013:
		AlphaCat Re 2011			AlphaCat Re 2012				AlphaCat 2013				AlphaCat 2014			AlphaCat ILS funds			Total
	As at December 31, 2013	$	9,809		$	1,313			$	51,744			$	21,982		$	21,895		$	106,743
	Return of investment	(5,825		)	—				(37,541		)		—			—			(43,366		)
	Fair value of retained interest on deconsolidation of AlphaCat ILS fund	—			—				—				—			113,455			113,455
	Income (loss) from operating affiliates	193			(36		)		1,475				1,611			1,684			4,927
	As at March 31, 2014	$	4,177		$	1,277			$	15,678			$	23,593		$	137,034		$	181,759
		Three Months Ended March 31, 2013
		AlphaCat Re 2011			AlphaCat Re 2012				AlphaCat 2013				AlphaCat ILS fund			Total
	As at December 31, 2012	$	62,792		$	29,319			$	45,000			$	20,000		$	157,111
	Return of investment	(46,436		)	(3,786		)		—				—			(50,222		)
	Income from operating affiliates	449			1,825				1,100				149			3,523
	As at March 31, 2013	$	16,805		$	27,358			$	46,100			$	20,149		$	110,412
	The following table presents the Company's investments in AlphaCat Re 2011, AlphaCat Re 2012, AlphaCat 2013, AlphaCat 2014 and the AlphaCat ILS funds in the Consolidated Financial Statements as at March 31, 2014:
		Investment in operating affiliates
		Cost			Voting ownership %			Equity ownership %			Carrying value
	AlphaCat Re 2011	$	4,178		43.7	%		22.3	%		$	4,177
	AlphaCat Re 2012	654			49	%		37.9	%		1,277
	AlphaCat 2013	16,454			40.9	%		19.7	%		15,678
	AlphaCat 2014	22,000			42.3	%		19.6	%		23,593
	AlphaCat ILS funds (a)	133,455			n/a			n/a			137,034
Total	$	176,741								$	181,759
(a)	Equity ownerships in the two funds were 9.1% and 49.7% respectively as at March 31, 2014.
The following table presents the Company's investments in AlphaCat Re 2011, AlphaCat Re 2012, AlphaCat 2013, AlphaCat 2014 and the AlphaCat ILS fund in the Consolidated Financial Statements as at December 31, 2013:
	Investment in operating affiliates
	Cost			Voting ownership %			Equity ownership %			Carrying value
AlphaCat Re 2011	$	9,882		43.7	%		22.3	%		$	9,809
AlphaCat Re 2012	654			49	%		37.9	%		1,313
AlphaCat 2013	45,000			40.9	%		19.7	%		51,744
AlphaCat 2014	22,000			42.3	%		19.6	%		21,982
AlphaCat ILS fund	20,000			—	%		9.1	%		21,895
Total	$	97,536								$	106,743
(c)	Notes payable and (income) attributable to operating affiliates
Notes are issued during the course of a year by Master Fund and AlphaCat Re to AlphaCat 2013, AlphaCat 2014 and the AlphaCat ILS funds (collectively the “feeder funds”) in order to fund the purchase of capital market products and to write collateralized reinsurance on their behalf. These notes are subsequently redeemed as the underlying transactions are settled. The Company’s investments in the feeder funds, together with investments made by third parties, are provided as consideration for these notes to Master Fund and AlphaCat Re, which are consolidated in the Company’s Consolidated Financial Statements. The effective economic interest in Master Fund and AlphaCat Re that results from these transactions is represented on the Consolidated Balance Sheet as notes payable to operating affiliates. The subsequent income or loss generated by the relevant capital market products or collateralized reinsurance is transferred to the operating affiliates as (income) loss attributable to operating affiliate investors in the Company’s Consolidated Statements of Comprehensive Income. To the extent that the (income) loss attributable to operating affiliate investors has not been returned to investors, it is included in accounts payable and accrued expenses in the Consolidated Balance Sheets.
Notes issued during the three months ended March 31, 2014 amounted to $334,444 (2013: $294,349). The underlying capital market products and collateralized reinsurance typically have at least a twelve month duration. The notes do not have any principal amount, since the final amount payable is dependent on the income or loss as discussed above. They also do not have any stated maturity date, since repayment is dependent on the settlement of the underlying transactions. During the three months ended March 31, 2014 there have been repayments of these notes amounting to $391,115 (2013: $nil).
The following tables present a reconciliation of the beginning and ending notes payable to operating affiliates for the three months ended March 31, 2014 and 2013:
	AlphaCat 2013			AlphaCat 2014				AlphaCat ILS funds				Total
As at December 31, 2013	$	223,809		$	—			$	215,463			$	439,272
Notes payable to operating affiliates recognized on deconsolidation of AlphaCat ILS fund	—			—				178,837				178,837
Issuance of notes payable to operating affiliates	—			149,707				184,737				334,444
Redemption of notes payable to operating affiliates	(175,349		)	—				(215,766		)		(391,115		)
Foreign exchange (gain) loss	(297		)	109				123				(65		)
As at March 31, 2014	$	48,163		$	149,816			$	363,394			$	561,373
	AlphaCat 2013			AlphaCat ILS funds				Total
As at December 31, 2012	$	—		$	—			$	—
Issuance of notes payable to operating affiliates	162,506			131,843				294,349
Foreign exchange gain	(1,067		)	(2,694		)		(3,761		)
As at March 31, 2013	$	161,439		$	129,149			$	290,588
The portion of notes payable to operating affiliates that were due to the Company, as an investor in the affiliates, and third party investors as at March 31, 2014 amounted to $141,343 and $420,030, respectively (December 31, 2013: $63,654 and $375,618).
The following table presents the (income) attributable to operating affiliate investors for the three months ended March 31, 2014 and 2013:
	March 31,			March 31,
	2014			2013
AlphaCat 2013	$	(10,476	)	$	(8,141	)
AlphaCat 2014	(10,789		)	—
AlphaCat ILS funds	(10,445		)	(1,936		)
(Income) attributable to operating affiliate investors	$	(31,710	)	$	(10,077	)
The portion of income attributable to operating affiliate investors that was due to the Company, as an investor in the affiliates, and third party investors for the three months ended March 31, 2014 amounted to $6,472 and $25,238, respectively (2013: $1,847 and $8,230).

Noncontrolling_interest

Noncontrolling interest	3 Months Ended
	Mar. 31, 2014
Noncontrolling Interest [Abstract]	'
Noncontrolling interest	'
	Noncontrolling interest
	On April 2, 2012, the Company joined with other investors in capitalizing PaCRe Ltd. ("PaCRe"), a Class 4 Bermuda reinsurer formed for the purpose of writing high excess property catastrophe reinsurance. The Company has an equity interest of 10% and the remaining 90% interest is held by third party investors. The Company has a majority voting equity interest in PaCRe and as a result, the financial statements of PaCRe are included in the Consolidated Financial Statements of the Company.
	The portion of PaCRe’s earnings attributable to third party investors is recorded in the Consolidated Statements of Comprehensive Income as net (income) loss attributable to noncontrolling interest. PaCRe's shareholder rights do not include redemption features within the control of the third party shareholders. The third party equity is recorded in the Company’s Consolidated Balance Sheets as noncontrolling interest.
	The portion of the earnings from the one consolidated AlphaCat ILS fund attributable to third party investors is recorded in the Consolidated Statements of Comprehensive Income as net (income) loss attributable to noncontrolling interest. The AlphaCat ILS funds have rights that enable shareholders, subject to certain limitations, to redeem their shares. The third party equity is therefore recorded in the Company’s Consolidated Balance Sheets as redeemable noncontrolling interest. When and if a redemption notice is received, the fair value of the redemption is reclassified to a liability.
	The following table presents a reconciliation of the beginning and ending balances of redeemable noncontrolling interest and noncontrolling interest for the three months ended March 31, 2014:
		Three Months Ended March 31, 2014
		Redeemable noncontrolling interest			Noncontrolling interest			Total
	As at December 31, 2013	$	86,512		$	497,657		$	584,169
	Income attributable to third parties	232			43,277			43,509
	Adjustment to noncontrolling interest as a result of deconsolidation	(78,354		)	—			(78,354		)
	As at March 31, 2014	$	8,390		$	540,934		$	549,324
	The following table presents a reconciliation of the beginning and ending balances of redeemable noncontrolling interest and noncontrolling interest for the three months ended March 31, 2013:
		Three Months Ended March 31, 2013
		Redeemable noncontrolling interest			Noncontrolling interest			Total
	As at December 31, 2012	$	—		$	434,280		$	434,280
	Issuance of shares	55,690			—			55,690
	Income (loss) attributable to third parties	587			(3,136		)	(2,549		)
	As at March 31, 2013	$	56,277		$	431,144		$	487,421

Derivative_instruments

Derivative instruments	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative instruments	'
	Derivative instruments
	The Company enters into derivative instruments for risk management purposes, specifically to hedge unmatched foreign currency exposures and interest rate exposures. As at March 31, 2014, the Company held foreign currency forward contracts to mitigate the risk of fluctuations in the U.S. dollar against a number of foreign currencies. As at March 31, 2014, the Company held two interest rate swaps to fix the payment of interest on the Company's 2006 and 2007 Junior Subordinated Deferrable Debentures, as well as three interest rate swaps and one cross-currency interest rate swap to fix the payment of interest and mitigate the foreign exchange rate impact on Flagstone's 2006 and 2007 Junior Subordinated Deferrable Debentures.
	The following table summarizes information on the classification and amount of the fair value of derivatives designated as hedging instruments on the consolidated balance sheets at March 31, 2014 and December 31, 2013:
			As at March 31, 2014								As at December 31, 2013
	Derivatives designated as hedging instruments:		Net notional exposure			Asset Derivative at Fair Value (a)			Liability Derivative at Fair Value (a)		Net notional exposure		Asset Derivative at Fair Value (a)		Liability Derivative at Fair Value (a)
	Foreign currency forward contracts		$	151,853		$	3,839		$	477	$	163,576	$	1,167	$	2,313
	Interest rate swap contracts		$	552,263		$	—		$	867	$	552,263	$	—	$	911
	(a)	Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses respectively on the Consolidated Balance Sheets.
	(a)	Classification within the fair value hierarchy
	As described in Note 4: "Fair value measurements" under U.S. GAAP, a company must determine the appropriate level in the fair value hierarchy for each fair value measurement. The assumptions used within the valuation of the Company's derivative instruments are observable in the marketplace, can be derived from observable data or are supported by observable levels at which other similar transactions are executed in the marketplace. Accordingly, these derivatives were classified within Level 2 of the fair value hierarchy.
	(b)	Derivative instruments designated as a fair value hedge
	The Company designates its foreign currency derivative instruments as fair value hedges and formally and contemporaneously documents all relationships between the derivative instruments and hedged items and links the derivative instruments to specific assets and liabilities. The Company assesses the effectiveness of the hedges, both at inception and on an on-going basis and determines whether the hedges are highly effective in offsetting changes in fair value of the linked hedged items.
	The following table provides the total impact on earnings, recognized in income within foreign exchange gains (losses), relating to the derivative instruments formally designated as fair value hedges along with the impact of the related hedged items for the three months ended March 31, 2014 and 2013:
	Foreign currency forward contracts		Three Months Ended March 31, 2014			Three Months Ended March 31, 2013
	Amount of gain (loss) recognized in income on derivative		$	3,303		$	1,261
	Amount of gain (loss) on hedged item recognized in income attributable to risk being hedged		$	(3,303	)	$	(1,261	)
	Amount of gain (loss) recognized in income on derivative (ineffective portion)		$	—		$	—
	(c)	Derivative instruments designated as a cash flow hedge
	The Company designates its interest rate derivative instruments as cash flow hedges and formally and contemporaneously documents all relationships between the hedging instruments and hedged items and links the derivative instruments to specific assets and liabilities. The Company assesses the effectiveness of the hedges, both at inception and on an on-going basis and determines whether the hedges are highly effective in offsetting changes in fair value of the linked hedged items. The Company currently applies the long haul method when assessing the hedge's effectiveness.
	The following table provides the total impact on other comprehensive income (loss) and earnings relating to the derivative instruments formally designated as cash flow hedges along with the impact of the related hedged items for the three months ended March 31, 2014 and 2013:
	Interest rate swap contracts		Three Months Ended March 31, 2014			Three Months Ended March 31, 2013
	Amount of effective portion recognized in other comprehensive income		$	3,208		$	1,608
	Amount of effective portion subsequently reclassified to earnings		$	(3,208	)	$	(1,608	)
	Amount of ineffective portion excluded from effectiveness testing		$	—		$	—
	The above balances relate to interest payments and have therefore been classified as finance expenses in the Consolidated Statements of Comprehensive Income.
	(d)	Balance sheet offsetting
	There was no balance sheet offsetting activity as at March 31, 2014 or December 31, 2013.
	The Company currently provides cash collateral as security for interest rate swap contracts. The Company does not provide cash collateral or financial instruments as security for foreign currency forward contracts. Our derivative instruments are generally traded under International Swaps and Derivatives Association master netting agreements, which establish terms that apply to all transactions. On a periodic basis, the amounts receivable from or payable to the counterparties are settled in cash.
	The Company has not elected to settle multiple transactions with an individual counterparty on a net basis.

Reserve_for_losses_and_loss_ex

Reserve for losses and loss expenses	3 Months Ended
	Mar. 31, 2014
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]	'
Reserve for losses and loss expenses	'
	Reserve for losses and loss expenses
	Reserves for losses and loss expenses are based in part upon the estimation of case reserves from broker, insured and ceding company reported data. The Company also uses statistical and actuarial methods to estimate ultimate expected losses and loss expenses, from which incurred but not reported losses can be calculated. The period of time from the occurrence of a loss to the reporting of a loss to the Company and to the settlement of the Company's liability may be several months or years. During this period, additional facts and trends may be revealed. As these factors become apparent, reserves will be adjusted, sometimes requiring an increase or decrease in the overall reserves of the Company, and at other times requiring a reallocation of incurred but not reported reserves to specific case reserves. These estimates are reviewed and adjusted regularly, and such adjustments, if any, are reflected in earnings in the period in which they become known. While management believes that it has made a reasonable estimate of ultimate losses, there can be no assurances that ultimate losses and loss expenses will not exceed this estimate.
	The following table represents an analysis of paid and unpaid losses and loss expenses incurred and a reconciliation of the beginning and ending unpaid losses and loss expenses for the three months ended March 31, 2014 and 2013:
			Three Months Ended
			March 31,				March 31,
			2014				2013
	Reserve for losses and loss expenses, beginning of period		$	3,030,399			$	3,517,573
	Losses and loss expenses recoverable		(370,154		)		(439,967		)
	Net reserves for losses and loss expenses, beginning of period		2,660,245				3,077,606
	Increase (decrease) in net losses and loss expenses incurred in respect of losses occurring in:
	Current year		202,086				210,569
	Prior years		(39,415		)		(65,798		)
	Total incurred losses and loss expenses		162,671				144,771
	Less net losses and loss expenses paid in respect of losses occurring in:
	Current year		(7,967		)		(4,838		)
	Prior years		(250,115		)		(255,274		)
	Total net paid losses		(258,082		)		(260,112		)
	Foreign exchange loss (gain)		11,818				(33,826		)
	Net reserve for losses and loss expenses, end of period		2,576,652				2,928,439
	Losses and loss expenses recoverable		348,407				429,252
	Reserve for losses and loss expenses, end of period		$	2,925,059			$	3,357,691
	Incurred losses and loss expenses comprise:
		Three Months Ended
		March 31,				March 31,
		2014				2013
	Gross losses and loss expenses	$	181,975			$	162,411
	Reinsurance recoverable	(19,304		)		(17,640		)
	Net incurred losses and loss expenses	$	162,671			$	144,771

Reinsurance

Reinsurance	3 Months Ended
	Mar. 31, 2014
Reinsurance Disclosures [Abstract]	'
Reinsurance	'
	Reinsurance
	The Company enters into reinsurance and retrocession agreements in order to mitigate its accumulation of loss, reduce its liability on individual risks, enable it to underwrite policies with higher limits and increase its aggregate capacity. The cession of insurance and reinsurance does not legally discharge the Company from its primary liability for the full amount of the policies, and the Company is required to pay the loss and bear collection risk if the reinsurer fails to meet its obligations under the reinsurance or retrocession agreement. Amounts recoverable from reinsurers are estimated in a manner consistent with the underlying liabilities.
	Credit risk
	The Company evaluates the financial condition of its reinsurers and monitors concentration of credit risk arising from its exposure to individual reinsurers. The reinsurance program is generally placed with reinsurers whose rating, at the time of placement, was A- or better as rated by Standard & Poor's or the equivalent with other rating agencies. Exposure to a single reinsurer is also controlled with restrictions dependent on rating. At March 31, 2014, 98.5% (December 31, 2013: 96.7%) of reinsurance recoverables (which includes loss reserves recoverable and recoverables on paid losses and $183,858 of total IBNR recoverable (December 31, 2013: $196,840)) were fully collateralized or from reinsurers rated A- or better.
	Reinsurance recoverables by reinsurer as at March 31, 2014 and December 31, 2013 are as follows:
		March 31, 2014					December 31, 2013
		Reinsurance Recoverable			% of Total		Reinsurance Recoverable		% of Total
	Top 10 reinsurers	$	291,958		75.7	%	$	340,253	75.6	%
	Other reinsurers’ balances > $1 million	85,348			22.2	%	100,784		22.4	%
	Other reinsurers’ balances < $1 million	8,133			2.1	%	9,197		2	%
	Total	$	385,439		100	%	$	450,234	100	%
			March 31, 2014
	Top 10 Reinsurers		Rating	Reinsurance Recoverable			% of Total
	Lloyd's Syndicates		A+	$	66,563		17.3	%
	Everest Re		A+	49,838			12.9	%
	Fully Collateralized		NR	39,120			10.1	%
	Hannover Re		AA-	36,377			9.4	%
	Third Point Reinsurance Ltd		A-	34,081			8.8	%
	Swiss Re		AA-	17,108			4.5	%
	Transatlantic Re		A+	13,449			3.5	%
	XL Re		A+	12,608			3.3	%
	Munich Re		AA-	12,333			3.2	%
	Merrimack Mutual Fire Insurance		A+	10,481			2.7	%
	Total			$	291,958		75.7	%
			December 31, 2013
	Top 10 Reinsurers		Rating	Reinsurance Recoverable			% of Total
	Lloyd's Syndicates		A+	$	73,398		16.3	%
	National Indemnity		AA+	51,037			11.3	%
	Everest Re		A+	48,055			10.7	%
	Hannover Re		AA-	41,483			9.2	%
	Fully Collateralized		NR	36,683			8.1	%
	Third Point Reinsurance Ltd		A-	30,428			6.8	%
	Swiss Re		AA-	20,022			4.5	%
	Transatlantic Re		A+	14,114			3.1	%
	XL Re		A+	12,673			2.8	%
	Munich Re		AA-	12,360			2.8	%
	Total			$	340,253		75.6	%
	NR: Not rated
	At March 31, 2014 and December 31, 2013, the provision for uncollectible reinsurance relating to reinsurance recoverables was $5,427 and $5,794, respectively. To estimate the provision for uncollectible reinsurance, the reinsurance recoverable is first allocated to applicable reinsurers. This determination is based on a process rather than an estimate, although an element of judgment is applied, especially in relation to ceded IBNR. The Company then uses default factors to determine the portion of a reinsurer’s balance deemed to be uncollectible. Default factors require considerable judgment and are determined in part using the current rating, or rating equivalent, of each reinsurer as well as other key considerations and assumptions.

Share_capital

Share capital	3 Months Ended
	Mar. 31, 2014
Stockholders' Equity Note [Abstract]	'
Share capital	'
	Share capital
	(a)	Authorized and issued
	The Company’s authorized share capital is 571,428,571 common shares with a par value of $0.175 per share. The holders of common shares are entitled to receive dividends. Holders of common shares are allocated one vote per share, provided that, if the controlled shares of any shareholder or group of related shareholders constitute more than 9.09 percent of the outstanding common shares of the Company, their voting power will be reduced to 9.09 percent.
	The Company may from time to time repurchase its securities, including common shares, Junior Subordinated Deferrable Debentures and Senior Notes. On February 5, 2014, the Board of Directors of the Company approved an increase in the Company's common share purchase authorization to $500,000. This amount is in addition to the $1,774,436 of common shares repurchased by the Company through February 5, 2014 under its previously authorized share repurchase programs.
	The Company has repurchased 62,171,982 common shares for an aggregate purchase price of $1,917,688 from the inception of its share repurchase program to March 31, 2014. The Company had $356,748 remaining under its authorized share repurchase program as of March 31, 2014.
	The Company expects the purchases under its share repurchase program to be made from time to time in the open market or in privately negotiated transactions. The timing, form and amount of the share repurchases under the program will depend on a variety of factors, including market conditions, the Company’s capital position relative to internal and rating agency targets, legal requirements and other factors. The repurchase program may be modified, extended or terminated by the Board of Directors at any time.
	The following table is a summary of the common shares issued and outstanding:
		Common Shares
	Common shares issued, December 31, 2013	154,488,497
	Restricted share awards vested, net of shares withheld	18,219
	Options exercised	90,019
	Direct issuance of common stock	359
	Common shares issued, March 31, 2014	154,597,094
	Treasury shares, March 31, 2014	(63,810,857	)
	Common shares outstanding, March 31, 2014	90,786,237
		Common Shares
	Common shares issued, December 31, 2012	152,698,191
	Restricted share awards vested, net of shares withheld	130,637
	Restricted share units vested, net of shares withheld	3,796
	Options exercised	128,020
	Direct issuance of common stock	183
	Deferred share units vested, net of shares withheld	2,935
	Common shares issued, March 31, 2013	152,963,762
	Treasury shares, March 31, 2013	(46,681,321	)
	Common shares outstanding, March 31, 2013	106,282,441
	(b)	Warrants
	During the three months ended March 31, 2014 and 2013, no warrants were exercised. Holders of the outstanding warrants are entitled to exercise the warrants in whole or in part at any time until the expiration date. The total outstanding warrants at March 31, 2014 were 5,174,114 (December 31, 2013: 5,296,056). No further warrants are anticipated to be issued.
	(c)	Deferred share units
	Under the terms of the Company’s Director Stock Compensation Plan, non-management directors may elect to receive their director fees in deferred share units rather than cash. The number of share units distributed in case of election under the plan is equal to the amount of the annual retainer fee otherwise payable to the director on such payment date divided by 100% of the fair market value of a share on such payment date. Additional deferred share units are issued in lieu of dividends that accrue on these deferred share units.  There were no outstanding deferred share units at March 31, 2014 (December 31, 2013: $nil).
	As of February 16, 2013, John Hendrickson became an employee director. As a result, his 5,039 deferred share units vested and 2,935 common shares were issued to him, net of shares withheld for taxes.
	(d)	Dividends
	On February 5, 2014, the Company announced a quarterly cash dividend of $0.30 (2013: $0.30) per common share and $0.30 per common share equivalent for which each outstanding warrant is exercisable. This dividend was paid on March 31, 2014 to holders of record on March 14, 2014.
	On February 6, 2013 the Company announced a special dividend in the amount of $2.00 per common share and $2.00 per common share equivalent for which each outstanding warrant is exercisable (the "2013 Special Dividend"). The 2013 Special Dividend was paid on February 26, 2013 to shareholders and warrant holders of record as of February 19, 2013.

Stock_plans

Stock plans	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock plans	'
	Stock plans
	(a)	Long Term Incentive Plan and Short Term Incentive Plan
	The Company’s Amended and Restated 2005 Long Term Incentive Plan (“LTIP”) provides for grants to employees of options, stock appreciation rights (“SARs”), restricted shares, restricted share units, performance shares, dividend equivalents or other share-based awards. In addition, the Company may issue restricted share awards or restricted share units in connection with awards issued under its annual Short Term Incentive Plan (“STIP”). The total number of shares reserved for issuance under the LTIP and STIP are 13,126,896 shares of which 1,987,700 shares are remaining. The LTIP and STIP are administered by the Compensation Committee of the Board of Directors. No SARs have been granted to date. Grant prices are established at the fair market value of the Company’s common shares at the date of grant.
	i.	Options
	Options may be exercised for voting common shares upon vesting. Options have a life of 10 years and vest either pro rata or at the end of the required service period from the date of grant. Fair value of the option awards at the date of grant is determined using the Black-Scholes option-pricing model.
	Expected volatility is based on stock price volatility of comparable publicly-traded companies. The Company used the simplified method consistent with U.S. GAAP authoritative guidance on stock compensation expenses to estimate expected lives for options granted during the period as historical exercise data was not available and the options met the requirement as set out in the guidance.
	The Company has not granted any stock options since September 4, 2009.
	There were no share compensation expenses in respect of options recorded for the three months ended March 31, 2014 and 2013.
	A modification event was triggered as a result of the 2013 Special Dividend. In accordance with the terms of the LTIP under which the options were issued, an adjustment was required to protect the holders of such stock options from changes in the value of the stock options following the declaration of the 2013 Special Dividend. The modification of the options included a decrease in the exercise price of each stock option and an increase in the number of shares underlying each stock option. The fair value of the options before and after the modification was unchanged.
	Activity with respect to options for the three months ended March 31, 2014 was as follows:
		Options			Weighted Average Grant Date Fair Value				Weighted Average Grant Date Exercise Price
	Options outstanding, December 31, 2013	1,572,713			$	6.66			$	18.88
	Options exercised	(90,019	)		4.25				25.46
	Options outstanding, March 31, 2014	1,482,694			$	6.81			$	18.48
	Activity with respect to options for the three months ended March 31, 2013 was as follows:
		Options			Weighted Average Grant Date Fair Value				Weighted Average Grant Date Exercise Price
	Options outstanding, December 31, 2012	1,823,947			$	6.52			$	20.69
	Options regranted (modified)	1,833,414			6.76				19.02
	Options exercised	(128,020	)		3.4				28.98
	Options cancelled (modified)	(1,733,139	)		6.76				20.12
	Options outstanding, March 31, 2013	1,796,202			$	6.75			$	18.95
	At March 31, 2014 and 2013, there were no unrecognized share compensation expenses in respect of options.
	ii.	Restricted share awards
	Restricted shares granted under the LTIP and STIP vest either pro rata or at the end of the required service period and contain certain restrictions during the vesting period, relating to, among other things, forfeiture in the event of termination of employment and transferability. Share compensation expenses of $7,001 were recorded for the three months ended March 31, 2014 (2013: $4,061). The expenses represent the proportionate accrual of the fair value of each grant based on the remaining vesting period.
	Activity with respect to unvested restricted share awards for the three months ended March 31, 2014 was as follows:
		Restricted Share Awards			Weighted Average Grant Date Fair Value
	Restricted share awards outstanding, December 31, 2013	2,684,745			$	33.74
	Restricted share awards granted	17,533			36.81
	Restricted share awards vested	(27,353	)		29.31
	Restricted share awards forfeited	(23,094	)		34.57
	Restricted share awards outstanding, March 31, 2014	2,651,831			$	33.8
	Activity with respect to unvested restricted share awards for the three months ended March 31, 2013 was as follows:
		Restricted Share Awards			Weighted Average Grant Date Fair Value
	Restricted share awards outstanding, December 31, 2012	2,170,547			$	29.24
	Restricted share awards granted	22,005			35.63
	Restricted share awards vested	(148,304	)		25.97
	Restricted share awards forfeited	(93,993	)		28.42
	Restricted share awards outstanding, March 31, 2013	1,950,255			$	29.6
	At March 31, 2014, there were $62,370 (December 31, 2013: $69,219) of total unrecognized share compensation expenses in respect of restricted share awards that are expected to be recognized over a weighted-average period of 3.0 years (December 31, 2013: 3.2 years).
	iii.	Restricted share units
	Restricted share units under the LTIP and STIP vest either ratably or at the end of the required service period and contain certain restrictions during the vesting period, relating to, among other things, forfeiture in the event of termination of employment and transferability. Share compensation expenses of $166 were recorded for the three months ended March 31, 2014 (2013: $121). The expenses represent the proportionate accrual of the fair value of each grant based on the remaining vesting period.
	Activity with respect to unvested restricted share units for the three months ended March 31, 2014 was as follows:
		Restricted Share Units			Weighted Average Grant Date Fair Value
	Restricted share units outstanding, December 31, 2013	66,518			$	33.74
	Restricted share units issued in lieu of cash dividends	495			33.74
	Restricted share units outstanding, March 31, 2014	67,013			$	33.74
	Activity with respect to unvested restricted share units for the three months ended March 31, 2013 was as follows:
		Restricted Share Units			Weighted Average Grant Date Fair Value
	Restricted share units outstanding, December 31, 2012	47,238			$	29.61
	Restricted share units vested	(5,468	)		25.27
	Restricted share units issued in lieu of cash dividends	3,020			29.69
	Restricted share units outstanding, March 31, 2013	44,790			$	30.15
	At March 31, 2014, there were $1,519 (December 31, 2013: $1,678) of total unrecognized share compensation expenses in respect of restricted share units that are expected to be recognized over a weighted-average period of 3.2 years (December 31, 2013: 3.4 years).
	iv.	Performance share awards
	The performance share awards contain a performance based component. The performance component relates to the compounded growth in the Dividend Adjusted Diluted Book Value per Share (“DBVPS”) over a three year period relative to the Company's peer group. For performance share awards granted during the period, the grant date Diluted Book Value per Share is based on the DBVPS at the end of the most recent financial reporting year. The Dividend Adjusted Performance Period End DBVPS will be the DBVPS three years after the grant date DBVPS. The fair value estimate earns over the requisite attribution period and the estimate will be reassessed at the end of each performance period which will reflect any adjustments in the consolidated statements of comprehensive income in the period in which they are determined.
	Share compensation expenses of $(20) were recorded for the three months ended March 31, 2014 (2013: $(1,864)). The negative expense is due to a reversal of expenses on unvested performance share awards based on a review of current and projected performance criteria.
	Activity with respect to unvested performance share awards for the three months ended March 31, 2014 was as follows:
		Performance Share Awards			Weighted Average Grant Date Fair Value
	Performance share awards outstanding, December 31, 2013	101,820			$	33.56
	Performance share awards conversion adjustment	(15,344	)		31.38
	Performance share awards outstanding, March 31, 2014	86,476			$	33.95
	Activity with respect to unvested performance share awards for the three months ended March 31, 2013 was as follows:
		Performance Share Awards			Weighted Average Grant Date Fair Value
Performance share awards outstanding, December 31, 2012	220,845			$	31.81
Performance share awards forfeited	(128,667	)		32.41
Performance share awards outstanding, March 31, 2013	92,178			$	30.99
At March 31, 2014, there were $1,207 (December 31, 2013: $1,642) of total unrecognized share compensation expenses in respect of performance share awards that are expected to be recognized over a weighted-average period of 1.9 years (December 31, 2013: 2.0 years).
(b)	Total share compensation expenses
The breakdown of share compensation expenses by award type was as follows:
	Three Months Ended
	March 31,				March 31,
	2014				2013
Restricted share awards	$	7,001			$	4,061
Restricted share units	166				121
Performance share awards	(20		)		(1,864		)
Total	$	7,147			$	2,318

Debt_and_financing_arrangement

Debt and financing arrangements	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Debt and financing arrangements	'
	Debt and financing arrangements
	(a)	Financing structure
	The financing structure at March 31, 2014 was:
		Commitment				Issued and outstanding (a)				Drawn
	2006 Junior Subordinated Deferrable Debentures	$	150,000			$	150,000			$	150,000
	2007 Junior Subordinated Deferrable Debentures	200,000				139,800				139,800
	Flagstone 2006 Junior Subordinated Deferrable Debentures	137,904				137,904				137,904
	Flagstone 2007 Junior Subordinated Deferrable Debentures	113,750				113,750				113,750
	Total debentures payable	601,654				541,454				541,454
	2010 Senior Notes due 2040	250,000				250,000				247,225
	Total debentures and senior notes payable	851,654				791,454				788,679
	$400,000 syndicated unsecured letter of credit facility	400,000				—				—
	$525,000 syndicated secured letter of credit facility	525,000				309,422				—
	$200,000 secured bi-lateral letter of credit facility	200,000				18,676				—
	Talbot FAL facility	25,000				25,000				—
	PaCRe senior secured letter of credit facility	10,000				294				—
	AlphaCat Re secured letter of credit facility	30,000				24,800				—
	IPC bi-lateral facility	40,000				19,817				—
	$375,000 Flagstone bi-lateral facility	375,000				292,532				—
	Total credit and other facilities	1,605,000				690,541				—
	Total debt and financing arrangements	$	2,456,654			$	1,481,995			$	788,679
	The financing structure at December 31, 2013 was:
		Commitment				Issued and outstanding (a)				Drawn
	2006 Junior Subordinated Deferrable Debentures	$	150,000			$	150,000			$	150,000
	2007 Junior Subordinated Deferrable Debentures	200,000				139,800				139,800
	Flagstone 2006 Junior Subordinated Deferrable Debentures	137,866				137,866				137,866
	Flagstone 2007 Junior Subordinated Deferrable Debentures	113,750				113,750				113,750
	Total debentures payable	601,616				541,416				541,416
	2010 Senior Notes due 2040	250,000				250,000				247,198
	Total debentures and senior notes payable	851,616				791,416				788,614
	$400,000 syndicated unsecured letter of credit facility	400,000				—				—
	$525,000 syndicated secured letter of credit facility	525,000				358,567				—
	$200,000 secured bi-lateral letter of credit facility	200,000				16,726				—
	Talbot FAL facility	25,000				25,000				—
	PaCRe senior secured letter of credit facility	10,000				294				—
	AlphaCat Re secured letter of credit facility	24,800				24,800				—
	IPC bi-lateral facility	40,000				20,177				—
	$375,000 Flagstone bi-lateral facility	375,000				305,686				—
	Total credit and other facilities	1,599,800				751,250				—
	Total debt and financing arrangements	$	2,451,416			$	1,542,666			$	788,614
	(a)	Indicates utilization of commitment amount, not necessarily drawn borrowings.
	(b)	Senior notes and junior subordinated deferrable debentures
	The following table summarizes the key terms of the Company's senior notes and junior subordinated deferrable debentures as at the issuance date for each placement.
	Description	Issuance date	Commitment			Maturity date	Fixed/Spread			Interest payments due
	2006 Junior Subordinated Deferrable Debentures	June 15, 2006	$	150,000		June 15, 2036	9.069	%	(b)	Quarterly
	Flagstone 2006 Junior Subordinated Deferrable Debentures	August 23, 2006	$	137,904		September 15, 2036	3.54	%	(a)	Quarterly
	2007 Junior Subordinated Deferrable Debentures	June 21, 2007	$	200,000		June 15, 2037	8.48	%	(b)	Quarterly
	Flagstone 2007 Junior Subordinated Deferrable Debentures	June 8, 2007	$	88,750		July 30, 2037	3	%	(a)	Quarterly
	Flagstone 2007 Junior Subordinated Deferrable Debentures	September 20, 2007	$	25,000		September 15, 2037	3.1	%	(a)	Quarterly
	2010 Senior Notes due 2040	January 26, 2010	$	250,000		January 26, 2040	8.875	%	(b)	Semi-annually in arrears
	(a)	Variable interest rate is the three-month LIBOR, reset quarterly, plus spread as noted in the table.
	(b)	Fixed interest rate.
	The following table summarizes the key terms of the Company's senior notes and junior subordinated deferrable debentures as at March 31, 2014:
	Description	Issuance date	Commitment			Maturity date	Fixed/Spread			Interest payments due
	2006 Junior Subordinated Deferrable Debentures	June 15, 2006	$	150,000		June 15, 2036	5.831	%	(b)	Quarterly
	Flagstone 2006 Junior Subordinated Deferrable Debentures	August 23, 2006	$	137,904		September 15, 2036	6.463	%	(b)	Quarterly
	2007 Junior Subordinated Deferrable Debentures	June 21, 2007	$	200,000		June 15, 2037	5.18	%	(b)	Quarterly
	Flagstone 2007 Junior Subordinated Deferrable Debentures	8-Jun-07	$	88,750		July 30, 2037	5.9	%	(b)	Quarterly
	Flagstone 2007 Junior Subordinated Deferrable Debentures	20-Sep-07	$	25,000		September 15, 2037	5.983	%	(b)	Quarterly
	2010 Senior Notes due 2040	26-Jan-10	$	250,000		January 26, 2040	8.875	%	(a)	Semi-annually in arrears
	(a)	Fixed interest rate.
	(b)	Interest rate has been fixed as a result of interest rate swap contracts entered into by the Company.
	Senior Notes
The Senior Notes due 2040 (the “2010 Senior Notes”) were part of a registered public offering. The 2010 Senior Notes mature on January 26, 2040.  The Company may redeem the notes, in whole at any time, or in part from time to time, at our option on not less than 30 nor more than 60 days’ notice, at a make-whole redemption price as described in “Description of the Notes - Optional Redemption” in the 2010 Senior Notes prospectus supplement.  In addition, the Company may redeem the notes, in whole, but not in part, at any time upon the occurrence of certain tax events as described in “Description of the Notes - Redemption for Tax Purposes’ in the prospectus supplement.
Debt issuance costs were deferred as an asset and are amortized over the life of the 2010 Senior Notes. There were no redemptions made during the three months ended March 31, 2014 and 2013.
The 2010 Senior Notes are unsecured and unsubordinated obligations of the Company and rank equally in right of payment with all of the Company’s existing and future unsecured and unsubordinated indebtedness. The 2010 Senior Notes will be effectively junior to all of the Company’s future secured debt, to the extent of the value of the collateral securing such debt, and will rank senior to all our existing and future subordinated debt. The 2010 Senior Notes are structurally subordinated to all obligations of the Company’s subsidiaries.
Future payments of principal of $250,000 on the 2010 Senior Notes are all expected to be after 2018.
Junior subordinated deferrable debentures
The Company participated in private placements of junior subordinated deferrable interest debentures due 2036 and 2037 (respectively, the “2006 Junior Subordinated Deferrable Debentures” and “2007 Junior Subordinated Deferrable Debentures”).
Debt issuance costs for the 2006 and 2007 Junior Subordinated Deferrable Debentures were deferred as an asset and were amortized to income over the five year optional redemption periods. They are redeemable at the Company's option at par. There were no redemptions made during the three months ended March 31, 2014 and 2013.
As part of the acquisition of Flagstone, the Company assumed junior subordinated deferrable debentures due 2036 and 2037 (respectively, the “Flagstone 2006 Junior Subordinated Deferrable Debentures” and “Flagstone 2007 Junior Subordinated Deferrable Debentures”). These debentures are redeemable quarterly at par. There were no redemptions made during the three months ended March 31, 2014 and 2013.
Future payments of principal of $541,454 on the debentures discussed above are all expected to be after 2018.
(c)	Credit facilities
i.	$400,000 syndicated unsecured letter of credit facility and $525,000 syndicated secured letter of credit facility
On March 9, 2012, the Company entered into a $400,000 four-year unsecured credit facility with Deutsche Bank Securities Inc., as syndication agent, JPMorgan Chase Bank, N.A. as administrative agent, Lloyds Securities Inc. and Suntrust Bank, as co-documentation agents and the lenders party thereto, which provides for letter of credit and revolving credit availability for the Company (the “Four Year Unsecured Facility”) (the full $400,000 of which is available for letters of credit and/or revolving loans). The Four Year Unsecured Facility was provided by a syndicate of commercial banks. Letters of credit under the Four Year Unsecured Facility are available to support obligations in connection with the insurance business of the Company and its subsidiaries. Loans under the Four Year Unsecured Facility are available for the general corporate and working capital purposes of the Company. The Company may request that existing lenders under the Four Year Unsecured Facility or prospective additional lenders agree to make available additional commitments from time to time so long as the aggregate commitments under the Four Year Unsecured Facility do not exceed $500,000.
Also on March 9, 2012, the Company entered into a $525,000 four-year secured credit facility, with the same parties, which provides for letter of credit availability for the Company (the “Four Year Secured Facility” and together with the Four Year Unsecured Facility, the “Credit Facilities”). The Four Year Secured Facility was also provided by a syndicate of commercial banks. Letters of credit under the Four Year Secured Facility will be available to support obligations in connection with the insurance business of the Company. The Company may request that existing lenders under the Four Year Secured Facility or prospective additional lenders agree to make available additional commitments from time to time so long as the aggregate commitments under the Four Year Secured Facility do not exceed $700,000. The obligations of the Company under the Four Year Secured Facility are secured by cash and securities deposited into cash collateral accounts from time to time with The Bank of New York Mellon.
As of March 31, 2014, there were $309,422 in outstanding letters of credit under the Four Year Secured Facility (December 31, 2013: $358,567) and $nil outstanding under the Four Year Unsecured Facility.
The Credit Facilities contain covenants that include, among other things (i) the requirement that the Company initially maintain a minimum level of consolidated net worth of at least $2,600,000 and, commencing with the end of the fiscal quarter ending March 31, 2012, to be increased quarterly by an amount equal to 50.0% of the Company’s consolidated net income (if positive) for such quarter plus 50.0% of the aggregate increases in the consolidated shareholders’ equity of the Company during such fiscal quarter by reason of the issuance and sale of common equity interests of the Company, including upon any conversion of debt securities of the Company into such equity interests, (ii) the requirement that the Company maintain at all times a consolidated total debt to consolidated total capital ratio not greater than 0.35:1.00, and (iii) the requirement that Validus Reinsurance, Ltd. and any other material insurance subsidiaries maintain a financial strength rating by A.M. Best of not less than “B++” (Fair).  In addition, the Credit Facilities contain customary negative covenants applicable to the Company, including limitations on the ability to pay dividends and other payments in respect of equity interests at any time that the Company is otherwise in default with respect to certain provisions under the respective Credit Facilities, limitations on the ability to incur liens, sell assets, merge or consolidate with others, enter into transactions with affiliates, and limitations on the ability of its subsidiaries to incur indebtedness. The Credit Facilities also contain customary affirmative covenants, representations and warranties and events of default for credit facilities of its type. As of March 31, 2014, and throughout the reporting periods presented, the Company was in compliance with all covenants and restrictions under the Credit Facilities.
On March 9, 2012, upon entering into the Credit Facilities, the Company terminated its (a) three-year bi-lateral $60,000 unsecured revolving credit facility, dated March 12, 2010, (b) $340,000 three-year unsecured credit facility, dated March 12, 2010 and (c) $500,000 five-year secured credit facility, dated March 12, 2007. No early termination penalties were incurred.
ii.	$25,000 Talbot FAL facility
Talbot holds a standby Letter of Credit facility (the “Talbot FAL facility”) to provide Funds at Lloyd’s to support the 2010, 2011, 2012, 2013, 2014 and 2015 underwriting years of account. As of March 31, 2014 the Company had $25,000 (December 31, 2013: $25,000) in outstanding letters of credit under the Talbot FAL facility.
The Talbot FAL facility contains affirmative covenants that include requirements for consolidated net worth and debt to capital ratios in line with those in place for the Credit Facilities and discussed above. The Talbot FAL facility also contains restrictions on our ability to incur debt at our subsidiaries, incur liens, sell assets and merge or consolidate with others. Other than in respect of existing and future preferred and hybrid securities, the payment of dividends and other payments in respect of equity interests are not permitted at any time that we are in default with respect to certain provisions under the Talbot FAL facility. As of March 31, 2014 and throughout the reporting periods presented, the Company was in compliance with all covenants and restrictions under the Talbot FAL facility.
iii.	$40,000 IPC bi-lateral facility
The Company assumed an existing evergreen letter of credit facility through the acquisition of IPC (the "IPC bi-lateral facility"). As of March 31, 2014, there were $19,817 outstanding letters of credit issued under the IPC bi-lateral facility (December 31, 2013: $20,177). As of March 31, 2014 and throughout the reporting periods presented, the Company was in compliance with all covenants and restrictions under the IPC bi-lateral facility.
iv.	$200,000 secured bi-lateral letter of credit facility
The Company holds an uncommitted secured bi-lateral letter of credit facility with Citibank Europe plc (the “Secured bi-lateral letter of credit facility”). As of March 31, 2014, $18,676 (December 31, 2013: $16,726) of letters of credit were outstanding under the Secured bi-lateral letter of credit facility. The Secured bi-lateral letter of credit facility has no fixed termination date and as of March 31, 2014, the Company is in compliance with all terms and covenants thereof.
v.	$10,000 PaCRe senior secured letter of credit facility
On May 11, 2012, PaCRe (as "Borrower") and its subsidiary, PaCRe Investments, Ltd. (as "Guarantor") entered into a secured evergreen credit and letter of credit facility with JPMorgan Chase Bank, N.A. This facility provides for revolving borrowings by the Borrower and for letters of credit issued by the Borrower to be used to support its reinsurance obligations in aggregate amount of $10,000. As of March 31, 2014, $294 (December 31, 2013: $294) of letters of credit were outstanding under this facility. As of March 31, 2014, and throughout the reporting periods presented, PaCRe was in compliance with all covenants and restrictions thereof.
vi.	$30,000 AlphaCat Re secured letter of credit facility
On January 2, 2013 AlphaCat Reinsurance Ltd. (as "Borrower") entered into a secured evergreen letter of credit facility with Comerica Bank. This facility provides for letters of credit issued by the Borrower to be used to support its reinsurance obligations in the aggregate amount of $24,800. During the period ended March 31, 2014 the size of the facility was increased to $30,000 from $24,800. As of March 31, 2014, $24,800 (December 31, 2013: $24,800) of letters of credit were outstanding under this facility. As of March 31, 2014, and throughout the reporting periods presented, AlphaCat Reinsurance Ltd., was in compliance with all covenants and restrictions thereof.
vii.	$375,000 Flagstone bi-lateral facility
As part of the Flagstone Acquisition, the Company assumed an evergreen Letters of Credit Master Agreement between Citibank Europe Plc and Flagstone Reassurance Suisse, S.A. (the “Flagstone Bi-Lateral Facility”). At March 31, 2014, the Flagstone Bi-Lateral Facility had $292,532 (December 31, 2013: $305,686) letters of credit issued and outstanding. As of March 31, 2014, and throughout the reporting periods presented, the Company was in compliance with all covenants and restrictions under the Flagstone Bi-Lateral Facility.
(d)	Finance expenses
Finance expenses consist of interest on our junior subordinated deferrable debentures, senior notes, the amortization of debt offering costs, fees relating to our credit facilities, bank charges and the costs of FAL as follows:
		Three Months Ended
		March 31,				March 31,
		2014				2013
2006 Junior Subordinated Deferrable Debentures		$	2,187			$	2,187
2007 Junior Subordinated Deferrable Debentures		1,809				1,809
Flagstone 2006 Junior Subordinated Deferrable Debentures		2,223				1,472
Flagstone 2007 Junior Subordinated Deferrable Debentures		1,750				1,072
2010 Senior Notes due 2040		5,597				5,597
Credit facilities		1,559				954
Bank charges		113				133
AlphaCat ILS funds fees (a)		677				1,114
Talbot FAL Facility		(15		)		31
Total finance expenses		$	15,900			$	14,369
(a)	Includes finance expenses incurred by AlphaCat Managers, Ltd. in relation to the AlphaCat ILS funds and fund-raising for AlphaCat 2014 and AlphaCat 2013 respectively.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive (Loss)	3 Months Ended
	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'
Accumulated other comprehensive (loss)	'
	The changes in accumulated other comprehensive income ("AOCI"), by component for the three months ended March 31, 2014 and 2013 is as follows:
		Three Months Ended March 31, 2014			Three Months Ended March 31, 2013
	Beginning balance, December 31	$	(617	)	$	(2,953	)
	Current period foreign currency translation adjustments	462			(9,785		)
	Ending balance, March 31	$	(155	)	$	(12,738	)

Commitments_and_contingencies

Commitments and contingencies	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and contingencies	'
	Commitments and contingencies
	(a)	Concentrations of credit risk
	The Company’s investments are managed following prudent standards of diversification. The Company attempts to limit its credit exposure by purchasing high quality fixed income investments to maintain an average portfolio, excluding bank loans, credit quality of AA- or higher, with mortgage and commercial mortgage-backed issues having an aggregate weighted average credit quality of AAA. In addition, the Company limits its exposure to any single issuer to 3% of its investment portfolio or less, excluding government and agency securities. With the exception of the Company's bank loan portfolio, which represents 9.5% of the Company's total investments as at March 31, 2014, the minimum credit rating of any security purchased is Baa3/BBB-. In the case where currently held investments are downgraded below Baa3/BBB-, the Company tolerates a holding of up to 2% of its investment portfolio in aggregate market value, or 10% with written authorization. Excluding bank loans, 1.0% of the portfolio had a split rating below Baa3/BBB- as at March 31, 2014. The Company did not have an aggregate exposure to any single issuer of more than 0.9% of its investment portfolio, other than with respect to government and agency securities as at March 31, 2014.
	(b)	Funds at Lloyd's
	The amounts provided under the Talbot FAL Facility would become a liability of the Company in the event of Syndicate 1183 declaring a loss at a level which would call on this arrangement.
	Talbot operates in Lloyd’s through a corporate member, Talbot 2002 Underwriting Capital Ltd (“T02”), which is the sole participant in Syndicate 1183. Lloyd’s sets T02’s required capital annually based on Syndicate 1183’s business plan, rating environment and reserving environment together with input arising from Lloyd’s discussions with, inter alia, regulatory and rating agencies. Such capital, called Funds at Lloyd’s (“FAL”), comprises: cash, investments and undrawn letters of credit provided by various banks.
	The amounts of cash, investments and letters of credit provided for each year of account as follows:
		2014 Underwriting Year		2013 Underwriting Year
	Talbot FAL facility	$	25,000	$	25,000
	Group funds	450,000		403,700
	Total	$	475,000	$	428,700
	The amounts which are provided as FAL are not available for distribution to the Company for the payment of dividends. Talbot’s corporate member may also be required to maintain funds under the control of Lloyd’s in excess of its capital requirement and such funds also may not be available for distribution to the Company for the payment of dividends. See Note 3 (d) for Talbot's investments pledged as collateral.
	(c)	Lloyd's Central Fund
	Whenever a member of Lloyd's is unable to pay its debts to policyholders, such debts may be payable by the Lloyd's Central Fund. If Lloyd's determines that the Central Fund needs to be increased, it has the power to assess premium levies on current Lloyd's members up to 3% of a member's underwriting capacity in any one year. The Company does not believe that any assessment is likely in the foreseeable future and has not provided any allowance for such an assessment. However, based on the Company's 2014 estimated premium income at Lloyd's of £625,000, at the March 31, 2014 exchange rate of £1 equals $1.6658 and assuming the maximum 3% assessment, the Company would be assessed approximately $31,234.
	(d)	Aquiline Commitment
	As discussed in Note 5 "Investments in affiliates," the Company entered into an Assignment and Assumption Agreement with Aquiline Capital Partners LLC, pursuant to which it assumed a total capital commitment of $50,000 which will expire on July 2, 2015. The Company's remaining commitment at March 31, 2014 was $17,890 (December 31, 2013: $17,890).

Related_party_transactions

Related party transactions	3 Months Ended
	Mar. 31, 2014
Related Party Transactions [Abstract]	'
Related party transactions	'
	Related party transactions
	The transactions listed below are classified as related party transactions as each counter party has either a direct or indirect shareholding in the Company.
	Aquiline Capital Partners, LLC and its related companies ("Aquiline"), which own 3,446,643 shares in the Company, hold warrants to purchase 2,756,088 shares, and have two employees on the Company's Board of Directors who do not receive compensation from the Company and are shareholders of Group Ark Insurance Holdings Ltd. ("Group Ark"). Christopher E. Watson, a director of the Company, serves as a director of Group Ark. Pursuant to reinsurance agreements with a subsidiary of Group Ark, the Company recognized gross premiums written during the three months ended March 31, 2014 of $1,373 (2013: $1,795), with $181 included in premiums receivable at March 31, 2014 (December 31, 2013: $242). The Company also recognized reinsurance premiums ceded during the three months ended March 31, 2014 of $5 (2013: $4). The Company recorded $2,688 of loss reserves recoverable at March 31, 2014 (December 31, 2013: $3,698). Earned premium adjustments of $1,441 (2013: $719) were recorded during the three months ended March 31, 2014.
	On November 24, 2009, the Company entered into an Investment Management Agreement with Conning, Inc. ("Conning") to manage a portion of the Company's investment portfolio. Aquiline acquired Conning on June 16, 2009. Jeffrey W. Greenberg, a director of the Company, serves as a director of Conning Holdings Corp., the parent company of Conning. Investment management fees earned by Conning for the three months ended March 31, 2014 were $56 (2013: $191) with $170 included in accounts payable and accrued expenses at March 31, 2014 (December 31, 2013: $283).
	On December 20, 2011, the Company entered into an Assignment and Assumption Agreement (the "Agreement") with Aquiline Capital Partners LLC, a Delaware limited liability company (the "Assignor") and Aquiline Capital Partners II GP (Offshore) Ltd., a Cayman Islands company limited by shares (the "General Partner") pursuant to which the Company has assumed 100% of the Assignor's interest in Aquiline Financial Services Fund II L.P. (the "Partnership") representing a total capital commitment of $50,000 (the "Commitment"), as a limited partner in the Partnership (the "Transferred Interest"). Messrs. Greenberg and Watson, directors of the Company, serve as managing principal and senior principal, respectively, of Aquiline Capital Partners LLC. For the three months ended March 31, 2014, the Company incurred $nil (2013: $120) in partnership fees and made $nil (2013: $1,341) capital contributions. There were no amounts included in accounts payable and accrued expenses at March 31, 2014 (December 31, 2013: $nil).
	Certain shareholders of the Company and their affiliates, as well as employers of entities associated with directors or officers have purchased insurance and/or reinsurance from the Company in the ordinary course of business. The Company believes these transactions were settled for arms length consideration.

Earnings_per_share

Earnings per share	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Earnings per share	'
	Earnings per share
	The following table sets forth the computation of basic and earnings per diluted share for the three months ended March 31, 2014 and 2013:
		Three Months Ended
		March 31,			March 31,
		2014			2013
	Basic earnings per share
	Net income	$	205,897		$	220,694
	(Income) loss attributable to noncontrolling interest	(43,509		)	2,549
	Net income available to Validus	162,388			223,243
	Less: Dividends and distributions declared on outstanding warrants	(1,552		)	(14,464		)
	Income available to common shareholders	$	160,836		$	208,779
	Weighted average number of common shares outstanding	93,451,999			107,386,438
	Basic earnings per share available to common shareholders	$	1.72		$	1.94
	Earnings per diluted share
	Net income	$	205,897		$	220,694
	(Income) loss attributable to noncontrolling interest	(43,509		)	2,549
	Net income available to Validus	162,388			223,243
	Less: Dividends and distributions declared on outstanding warrants	—			(14,464		)
	Income available to common shareholders	$	162,388		$	208,779
	Weighted average number of common shares outstanding	93,451,999			107,386,438
	Share equivalents:
	Warrants	2,716,010			—
	Stock options	750,369			1,631,556
	Unvested restricted shares	881,141			1,035,005
	Weighted average number of diluted common shares outstanding	97,799,519			110,052,999
	Earnings per diluted share available to common shareholders	$	1.66		$	1.9
	Share equivalents that would result in the issuance of common shares of 12,498 (2013: 104,405) were outstanding for the three months ended March 31, 2014, but were not included in the computation of earnings per diluted share because the effect would be antidilutive.

Segment_information

Segment information	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment information	'
	Segment information
	The Company conducts its operations worldwide through three operating segments, which have been determined under U.S. GAAP segment reporting to be Validus Re, AlphaCat and Talbot. The Company’s operating segments are strategic business units that offer different products and services. They are managed and have capital allocated separately because each segment requires different strategies.
	Validus Re Segment
	The Validus Re segment is focused on short-tail lines of reinsurance. The primary lines in which the segment conducts business are property, marine and specialty which includes agriculture, aerospace and aviation, financial lines of business, nuclear, terrorism, life, accident & health, workers’ compensation, crisis management, contingency, motor, technical lines, composite and trade credit.
	AlphaCat Segment
	The AlphaCat segment manages strategic relationships that leverage the Company’s underwriting and investment expertise and earns management, performance and underwriting fees primarily from the Company’s operating affiliates, AlphaCat Re 2011, AlphaCat Re 2012, AlphaCat 2013 and AlphaCat 2014, as well as PaCRe and the AlphaCat ILS funds.
	Talbot Segment
	The Talbot segment focuses on a wide range of marine and energy, war, political violence, commercial property, financial institutions, contingency, bloodstock, accident & health and aviation classes of business on an insurance or facultative reinsurance basis and principally property, aerospace and marine classes of business on a treaty reinsurance basis.
	Corporate and eliminations
	The Company has a corporate function ("corporate"), which includes the activities of the parent company, and which carries out certain functions for the group. Corporate includes ‘non-core’ underwriting expenses, predominantly general and administrative and stock compensation expenses. Corporate also denotes the activities of certain key executives such as the Chief Executive Officer and Chief Financial Officer. For internal reporting purposes, corporate is reflected separately, however corporate is not considered an operating segment under these circumstances. Other reconciling items include, but are not limited to, the elimination of inter segment revenues and expenses and unusual items that are not allocated to segments.
	The following tables summarize the results of our operating segments and "Corporate":
	Three Months Ended March 31, 2014		Validus Re Segment				AlphaCat Segment				Talbot Segment				Corporate & Eliminations				Total
	Underwriting income
	Gross premiums written		$	678,986			$	84,347			$	290,695			$	(42,037	)		$	1,011,991
	Reinsurance premiums ceded		(142,640		)		(3,700		)		(90,605		)		42,037				(194,908		)
	Net premiums written		536,346				80,647				200,090				—				817,083
	Change in unearned premiums		(297,960		)		(49,964		)		13,798				—				(334,126		)
	Net premiums earned		238,386				30,683				213,888				—				482,957
	Underwriting deductions
	Losses and loss expenses		68,155				(7,860		)		102,376				—				162,671
	Policy acquisition costs		39,245				2,980				44,928				(1,504		)		85,649
	General and administrative expenses		18,195				4,128				35,149				16,973				74,445
	Share compensation expenses		2,208				(10		)		2,582				2,367				7,147
	Total underwriting deductions		127,803				(762		)		185,035				17,836				329,912
	Underwriting income (loss)		$	110,583			$	31,445			$	28,853			$	(17,836	)		$	153,045
	Net investment income		18,765				880				4,686				(969		)		23,362
	Other income		6,770				9,497				17				(2,454		)		13,830
	Finance expenses		(3,839		)		(683		)		(26		)		(11,352		)		(15,900		)
	Operating income (loss) before taxes, income from operating affiliates and (income) attributable to operating affiliate investors		132,279				41,139				33,530				(32,611		)		174,337
	Tax benefit (expense)		578				—				130				(668		)		40
	Income from operating affiliates		—				4,927				—				—				4,927
	(Income) attributable to operating affiliate investors		—				(31,710		)		—				—				(31,710		)
	Net operating income (loss)		$	132,857			$	14,356			$	33,660			$	(33,279	)		$	147,594
	Net realized gains on investments		2,446				1,225				69				—				3,740
	Change in net unrealized gains (losses) on investments		11,898				45,872				2,577				(4,654		)		55,693
	Income from investment affiliate		5,348				—				—				—				5,348
	Foreign exchange (losses) gains		(6,176		)		38				(150		)		(190		)		(6,478		)
	Net income (loss)		$	146,373			$	61,491			$	36,156			$	(38,123	)		$	205,897
	Net (income) attributable to noncontrolling interest		—				(43,509		)		—				—				(43,509		)
	Net income (loss) available (attributable) to Validus		$	146,373			$	17,982			$	36,156			$	(38,123	)		$	162,388
	Selected ratios (a):
	Net premiums written / Gross premiums written		79		%		95.6		%		68.8		%						80.7		%
	Losses and loss expenses		28.6		%		(25.6		)%		47.9		%						33.7		%
	Policy acquisition costs		16.5		%		9.7		%		21		%						17.7		%
	General and administrative expenses (b)		8.5		%		13.4		%		17.6		%						16.9		%
	Expense ratio		25		%		23.1		%		38.6		%						34.6		%
	Combined ratio		53.6		%		(2.5		)%		86.5		%						68.3		%
	Total assets		$	5,603,777			$	1,582,014			$	2,975,510			$	94,788			$	10,256,089
	(a)	Ratios are based on net premiums earned.
	(b)	The general and administrative expense ratio includes share compensation expenses.
	Three Months Ended March 31, 2013		Validus Re Segment				AlphaCat Segment				Talbot Segment				Corporate & Eliminations				Total
	Underwriting income
	Gross premiums written		$	747,963			$	96,516			$	293,530			$	(33,249	)		$	1,104,760
	Reinsurance premiums ceded		(125,728		)		—				(94,737		)		33,249				(187,216		)
	Net premiums written		622,235				96,516				198,793				—				917,544
	Change in unearned premiums		(319,101		)		(68,899		)		1,517				—				(386,483		)
	Net premiums earned		303,134				27,617				200,310				—				531,061
	Underwriting deductions
	Losses and loss expenses		73,402				—				71,369				—				144,771
	Policy acquisition costs		51,744				2,638				40,526				(1,297		)		93,611
	General and administrative expenses		29,441				4,037				30,912				15,889				80,279
	Share compensation expenses		1,413				77				1,405				(577		)		2,318
	Total underwriting deductions		156,000				6,752				144,212				14,015				320,979
Underwriting income (loss)		$	147,134			$	20,865			$	56,098			$	(14,015	)		$	210,082
Net investment income		23,193				881				4,718				(3,143		)		25,649
Other income		13,490				6,633				—				(17,438		)		2,685
Finance expenses		(3,252		)		(1,248		)		(74		)		(9,795		)		(14,369		)
Operating income (loss) before taxes, income from operating affiliates and (income) attributable to operating affiliate investors		180,565				27,131				60,742				(44,391		)		224,047
Tax expense (benefit)		1,757				—				(1,054		)		(385		)		318
Income from operating affiliates		—				3,523				—				—				3,523
(Income) attributable to operating affiliate investors		—				(10,077		)		—				—				(10,077		)
Net operating income (loss)		$	182,322			$	20,577			$	59,688			$	(44,776	)		$	217,811
Net realized gains on investments		1,593				—				128				—				1,721
Change in net unrealized (losses) on investments		(2,193		)		(4,788		)		(256		)		—				(7,237		)
Income from investment affiliate		1,477				—				—				—				1,477
Foreign exchange gains (losses)		11,162				(1,187		)		(3,918		)		865				6,922
Net income (loss)		$	194,361			$	14,602			$	55,642			$	(43,911	)		$	220,694
Net loss attributable to noncontrolling interest		—				2,549				—				—				2,549
Net income (loss) available (attributable) to Validus		$	194,361			$	17,151			$	55,642			$	(43,911	)		$	223,243
Selected ratios (a):
Net premiums written / Gross premiums written		83.2		%		100		%		67.7		%						83.1		%
Losses and loss expenses		24.2		%		0		%		35.6		%						27.3		%
Policy acquisition costs		17.1		%		9.6		%		20.2		%						17.6		%
General and administrative expenses (b)		10.2		%		14.9		%		16.1		%						15.6		%
Expense ratio		27.3		%		24.5		%		36.3		%						33.2		%
Combined ratio		51.5		%		24.5		%		71.9		%						60.5		%
Total assets		$	6,299,481			$	1,189,190			$	3,043,312			$	32,417			$	10,564,400
(a)	Ratios are based on net premiums earned.
(b)	The general and administrative expense ratio includes share compensation expenses.
The Company’s exposures are generally diversified across geographic zones. The following tables set forth the gross premiums written allocated to the territory of coverage exposure for the periods indicated:
	Three Months Ended March 31, 2014
	Gross Premiums Written
	Validus Re				AlphaCat				Talbot				Eliminations				Total				%
United States	$	191,868			$	8,698			$	26,311			$	(5,665	)		$	221,212			21.9	%
Worldwide excluding United States (a)	61,534				7,678				37,182				(4,740		)		101,654				9.9	%
Australia and New Zealand	12,816				1,019				2,880				(281		)		16,434				1.6	%
Europe	37,896				1,301				18,791				(2,817		)		55,171				5.5	%
Latin America and Caribbean	6,934				—				31,239				(3,052		)		35,121				3.5	%
Japan	159				—				538				(53		)		644				0.1	%
Canada	2,899				216				3,145				(523		)		5,737				0.6	%
Rest of the world (b)	53,850				—				18,404				(1,798		)		70,456				7	%
Sub-total, non United States	176,088				10,214				112,179				(13,264		)		285,217				28.2	%
Worldwide including United States (a)	105,191				65,435				23,653				(6,646		)		187,633				18.5	%
Other location non-specific (c)	205,839				—				128,552				(16,462		)		317,929				31.4	%
Total	$	678,986			$	84,347			$	290,695			$	(42,037	)		$	1,011,991			100	%
	Three Months Ended March 31, 2013
	Gross Premiums Written
	Validus Re				AlphaCat				Talbot				Eliminations				Total				%
United States	$	236,496			$	17,489			$	20,541			$	(6,864	)		$	267,662			24.2	%
Worldwide excluding United States (a)	50,308				14,689				39,458				(4,508		)		99,947				9	%
Australia and New Zealand	25,026				2,183				3,005				(230		)		29,984				2.7	%
Europe	40,870				1,964				18,311				(2,848		)		58,297				5.3	%
Latin America and Caribbean	8,418				—				42,000				(3,218		)		47,200				4.3	%
Japan	737				—				654				(50		)		1,341				0.1	%
Canada	2,642				318				2,706				(525		)		5,141				0.5	%
Rest of the world (b)	19,079				—				18,314				(1,403		)		35,990				3.3	%
Sub-total, non United States	147,080				19,154				124,448				(12,782		)		277,900				25.2	%
Worldwide including United States (a)	100,540				59,873				19,156				(3,689		)		175,880				15.9	%
Other location non-specific (c)	263,847				—				129,385				(9,914		)		383,318				34.7	%
Total	$	747,963			$	96,516			$	293,530			$	(33,249	)		$	1,104,760			100	%
(a)	Represents risks in two or more geographic zones.
(b)	Represents risks in one geographic zone.
(c)	The other locations non-specific category refers to business for which an analysis of exposure by geographic zone is not applicable, such as marine and aerospace risks, since these exposures can span multiple geographic areas and, in some instances, are not fixed locations.

Subsequent_events

Subsequent events	3 Months Ended
	Mar. 31, 2014
Subsequent Events [Abstract]	'
Subsequent events	'
	Subsequent events
	(a)	Quarterly Dividend
	On April 30, 2014, the Company announced a quarterly cash dividend of $0.30 per each common share and $0.30 per common share equivalent for which each outstanding warrant is exercisable, payable on June 30, 2014 to holders of record on June 13, 2014.

Significant_accounting_policie

Significant accounting policies (Policies)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Basis of preparation	'
	These unaudited Consolidated Financial Statements include Validus Holdings, Ltd. and its wholly and majority owned subsidiaries (together the "Company") and have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 in Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In addition, the year-end balance sheet data was derived from audited financial statements but does not include all disclosures required by U.S. GAAP. This Quarterly Report on Form 10-Q should be read in conjunction with the financial statements and related notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2013, as filed with the U.S. Securities and Exchange Commission (the "SEC").
	In the opinion of management, these unaudited consolidated financial statements reflect all adjustments (including normal recurring adjustments) considered necessary for a fair presentation of the Company's financial position and results of operations as at the end of and for the periods presented. To facilitate comparison of information, certain amounts in prior periods have been reclassified to conform to current period presentation. The consolidated statement of cash flows for the three months ended March 31, 2013 includes a reclassification of $19,400 from cash flows used in financing activities to cash flows provided by operating activities to revise the presentation of subscriptions received in advance from third party investors. For the three months ended March 31, 2013, $10,077 within finance expenses has been reclassified into income attributable to operating affiliate investors to conform to current period presentation. All significant intercompany accounts and transactions have been eliminated.
Use of estimates	'
	The preparation of these financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. While management believes that the amounts included in the Consolidated Financial Statements reflect its best estimates and assumptions, actual results could differ materially from those estimates. The Company’s principal estimates include:
	•reserve for losses and loss expenses;
	•premium estimates for business written on a line slip or proportional basis;
	•the valuation of goodwill and intangible assets;
	•reinsurance recoverable balances including the provision for uncollectible amounts; and
	•investment valuation of financial assets.
Reserves for losses and loss expenses	'
	Reserves for losses and loss expenses are based in part upon the estimation of case reserves from broker, insured and ceding company reported data. The Company also uses statistical and actuarial methods to estimate ultimate expected losses and loss expenses, from which incurred but not reported losses can be calculated. The period of time from the occurrence of a loss to the reporting of a loss to the Company and to the settlement of the Company's liability may be several months or years. During this period, additional facts and trends may be revealed. As these factors become apparent, reserves will be adjusted, sometimes requiring an increase or decrease in the overall reserves of the Company, and at other times requiring a reallocation of incurred but not reported reserves to specific case reserves. These estimates are reviewed and adjusted regularly, and such adjustments, if any, are reflected in earnings in the period in which they become known. While management believes that it has made a reasonable estimate of ultimate losses, there can be no assurances that ultimate losses and loss expenses will not exceed this estimate.
Reinsurance	'
	To estimate the provision for uncollectible reinsurance, the reinsurance recoverable is first allocated to applicable reinsurers. This determination is based on a process rather than an estimate, although an element of judgment is applied, especially in relation to ceded IBNR. The Company then uses default factors to determine the portion of a reinsurer’s balance deemed to be uncollectible. Default factors require considerable judgment and are determined in part using the current rating, or rating equivalent, of each reinsurer as well as other key considerations and assumptions.

Investments_Tables

Investments (Tables)	3 Months Ended
	Mar. 31, 2014
Investments [Abstract]	'
Amortized cost, gross unrealized gains and (losses) and estimated fair value of investments	'
	The amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments at March 31, 2014 were as follows:
		Amortized Cost or Cost			Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
	U.S. government and government agency	$	1,122,846		$	2,241			$	(4,232	)		$	1,120,855
	Non-U.S. government and government agency	438,415			5,138				(1,224		)		442,329
	U.S. states, municipalities and political subdivisions	43,960			626				(122		)		44,464
	Agency residential mortgage-backed securities	293,013			8,201				(1,653		)		299,561
	Non-agency residential mortgage-backed securities	16,721			254				(645		)		16,330
	U.S. corporate	1,331,550			9,315				(3,455		)		1,337,410
	Non-U.S. corporate	699,404			6,460				(1,973		)		703,891
	Bank loans	640,672			4,678				(1,649		)		643,701
	Catastrophe bonds	30,500			1,747				—				32,247
	Asset-backed securities	623,631			1,408				(540		)		624,499
	Commercial mortgage-backed securities	22,312			7				(6		)		22,313
	Total fixed maturities	5,263,024			40,075				(15,499		)		5,287,600
	Total short-term investments	831,679			121				—				831,800
	Other investments
	Fund of hedge funds	2,977			138				(921		)		2,194
	Hedge funds (a)	581,369			110,058				(84,965		)		606,462
	Private equity investments	12,068			2,562				(668		)		13,962
	Investment funds	30,311			188				—				30,499
	Mutual funds	6,199			3,658				—				9,857
	Total other investments	632,924			116,604				(86,554		)		662,974
	Total investments including noncontrolling interests	$	6,727,627		$	156,800			$	(102,053	)		$	6,782,374
	Noncontrolling interest (a)	$	(512,121	)	$	(95,750	)		$	76,468			$	(531,403	)
	Redeemable noncontrolling interest (b)	$	(1,976	)	$	—			$	—			$	(1,976	)
	Total investments excluding noncontrolling interests	$	6,213,530		$	61,050			$	(25,585	)		$	6,248,995
	(a)	Included in the hedge funds balance are investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.
	(b)	Included in the total investments balance are investments held by one AlphaCat ILS fund which is consolidated by the Company but in which the Company has an equity interest of less than 100%. The remaining interests are held by third party investors and included in the Consolidated Balance Sheets as redeemable noncontrolling interest.
	The amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments at December 31, 2013 were as follows:
		Amortized Cost or Cost			Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
	U.S. government and government agency	$	1,368,826		$	2,589			$	(6,736	)		$	1,364,679
	Non-U.S. government and government agency	454,578			6,511				(2,021		)		459,068
	U.S. states, municipalities and political subdivisions	42,978			459				(317		)		43,120
	Agency residential mortgage-backed securities	305,450			8,310				(2,261		)		311,499
	Non-agency residential mortgage-backed securities	16,530			143				(914		)		15,759
	U.S. corporate	1,328,960			9,208				(5,684		)		1,332,484
	Non-U.S. corporate	711,581			5,917				(3,173		)		714,325
	Bank loans	712,859			5,659				(1,402		)		717,116
	Catastrophe bonds	72,000			2,551				—				74,551
	Asset-backed securities	509,091			1,409				(843		)		509,657
	Total fixed maturities	5,522,853			42,756				(23,351		)		5,542,258
	Total short-term investments	751,734			45				(1		)		751,778
	Other investments
	Fund of hedge funds	3,141			83				(921		)		2,303
	Hedge funds (a)	584,518			71,641				(95,076		)		561,083
	Private equity investments	12,333			1,410				(258		)		13,485
	Investment funds	31,537			92				—				31,629
	Mutual funds	6,199			3,617				—				9,816
	Total other investments	637,728			76,843				(96,255		)		618,316
	Total investments including noncontrolling interests	$	6,912,315		$	119,644			$	(119,607	)		$	6,912,352
	Noncontrolling interest (a)	(512,121		)	(62,850		)		85,569				(489,402		)
	Redeemable noncontrolling interest (b)	$	(18,365	)	$	—			$	—			$	(18,365	)
	Total investments excluding noncontrolling interests	$	6,381,829		$	56,794			$	(34,038	)		$	6,404,585
	(a)	Included in the hedge funds balance are investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.
	(b)	Included in the total investments balance are investments held by two AlphaCat ILS funds which are consolidated by the Company but in which the Company has an equity interest of less than 100%. The remaining interests are held by third party investors and included in the Consolidated Balance Sheets as redeemable noncontrolling interest.
Investment ratings on fixed maturities	'
	The following table sets forth certain information regarding the investment ratings of the Company’s fixed maturities portfolio as at March 31, 2014 and December 31, 2013. Investment ratings are the lower of Moody’s or Standard & Poor’s rating for each investment security, presented in Standard & Poor’s equivalent rating. For investments where Moody’s and Standard & Poor’s ratings are not available, Fitch ratings are used and presented in Standard & Poor’s equivalent rating.
		March 31, 2014						December 31, 2013
		Estimated Fair Value			% of Total			Estimated Fair Value				% of Total
	AAA	$	906,648		17.1	%		$	788,490			14.2	%
	AA	2,124,629			40.2	%		2,378,491				42.9	%
	A	1,178,357			22.3	%		1,174,562				21.2	%
	BBB	397,563			7.5	%		420,559				7.6	%
	Total investment-grade fixed maturities	4,607,197			87.1	%		4,762,102				85.9	%
	BB	336,265			6.4	%		350,678				6.3	%
	B	321,128			6.1	%		390,430				7	%
	CCC	4,247			0.1	%		4,659				0.1	%
	CC	2,602			—	%		2,731				0.1	%
	D/NR	16,161			0.3	%		31,658				0.6	%
	Total non-investment grade fixed maturities	680,403			12.9	%		780,156				14.1	%
	Total fixed maturities	$	5,287,600		100	%		$	5,542,258			100	%
Fixed maturities investments by contractual maturity	'
	The amortized cost and estimated fair value amounts for fixed maturities held at March 31, 2014 and December 31, 2013 are shown below by contractual maturity. Actual maturity may differ from contractual maturity because certain borrowers may have the right to call or prepay certain obligations with or without call or prepayment penalties.
		March 31, 2014							December 31, 2013
		Amortized Cost			Estimated Fair Value				Amortized Cost				Estimated Fair Value
	Due in one year or less	$	625,774		$	629,800			$	688,855			$	692,768
	Due after one year through five years	3,311,970			3,325,578				3,603,459				3,613,847
	Due after five years through ten years	366,524			366,409				396,389				395,633
	Due after ten years	3,079			3,110				3,079				3,095
		4,307,347			4,324,897				4,691,782				4,705,343
	Asset-backed and mortgage-backed securities	955,677			962,703				831,071				836,915
	Total fixed maturities	$	5,263,024		$	5,287,600			$	5,522,853			$	5,542,258
Net investment income	'
	Net investment income was derived from the following sources:
		Three Months Ended
		March 31, 2014			March 31, 2013
	Fixed maturities and short-term investments	$	23,297		$	27,531
	Cash and cash equivalents	1,957			533
	Securities lending income	2			—
	Total gross investment income	25,256			28,064
	Investment expenses	(1,894		)	(2,415		)
	Total net investment income	$	23,362		$	25,649
Analysis of net realized gains and change in unrealized (losses) gains on investments	'
	The following represents an analysis of net realized gains and the change in net unrealized gains (losses) on investments:
		Three Months Ended
		March 31, 2014			March 31, 2013
	Fixed maturities, short-term and other investments and cash equivalents
	Gross realized gains	$	5,296		$	10,720
	Gross realized (losses)	(1,556		)	(8,999		)
	Net realized gains on investments	3,740			1,721
	Change in net unrealized gains (losses) on investments (a)	55,693			(7,237		)
	Total net realized gains and change in net unrealized gains (losses) on investments including noncontrolling interest	59,433			(5,516		)
	Noncontrolling interest (a)	(42,002		)	4,651
	Total net realized gains and change in net unrealized gains (losses) on investments excluding noncontrolling interest	$	17,431		$	(865	)
	(a)	Includes change in net unrealized (gains) losses on investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and is included in the Consolidated Statements of Comprehensive Income as net (income) loss attributable to noncontrolling interest.
Investments pledged as collateral under credit facilities	'
	The following tables outline investments pledged as collateral under the Company's credit facilities. For further details on the credit facilities, please refer to Note 12: “Debt and financing arrangements.”
			March 31, 2014
	Description		Commitment			Issued and Outstanding				Investments and cash pledged as collateral
	$400,000 syndicated unsecured letter of credit facility		$	400,000		$	—			$	—
	$525,000 syndicated secured letter of credit facility		525,000			309,422				499,905
	$200,000 secured bi-lateral letter of credit facility		200,000			18,676				35,225
	Talbot FAL facility		25,000			25,000				30,897
	PaCRe senior secured letter of credit facility		10,000			294				—
	AlphaCat Re secured letter of credit facility		30,000			24,800				30,022
	IPC bi-lateral facility		40,000			19,817				96,960
	$375,000 Flagstone bi-lateral facility		375,000			292,532				453,943
			$	1,605,000		$	690,541			$	1,146,952
			December 31, 2013
	Description		Commitment			Issued and Outstanding				Investments and cash pledged as collateral
	$400,000 syndicated unsecured letter of credit facility		$	400,000		$	—			$	—
	$525,000 syndicated secured letter of credit facility		525,000			358,567				507,620
	$200,000 secured bi-lateral letter of credit facility		200,000			16,726				130,256
	Talbot FAL facility		25,000			25,000				30,801
	PaCRe senior secured letter of credit facility		10,000			294				—
	AlphaCat Re secured letter of credit facility		24,800			24,800				24,806
	IPC bi-lateral facility		40,000			20,177				98,465
	$375,000 Flagstone bi-lateral facility		375,000			305,686				454,458
			$	1,599,800		$	751,250			$	1,246,406

Fair_value_measurements_Tables

Fair value measurements (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair value hierarchy - allocation of investments	'
	At March 31, 2014, the Company’s investments were allocated between Levels 1, 2 and 3 as follows:
		Level 1				Level 2				Level 3			Total
	U.S. government and government agency	$	—			$	1,120,855			$	—		$	1,120,855
	Non-U.S. government and government agency	—				442,329				—			442,329
	U.S. states, municipalities and political subdivisions	—				44,464				—			44,464
	Agency residential mortgage-backed securities	—				299,561				—			299,561
	Non-agency residential mortgage-backed securities	—				16,330				—			16,330
	U.S. corporate	—				1,337,410				—			1,337,410
	Non-U.S. corporate	—				703,891				—			703,891
	Bank loans	—				643,701				—			643,701
	Catastrophe bonds	—				25,544				6,703			32,247
	Asset-backed securities	—				624,499				—			624,499
	Commercial mortgage-backed securities	—				22,313				—			22,313
	Total fixed maturities	—				5,280,897				6,703			5,287,600
	Total short-term investments	817,937				13,863				—			831,800
	Other investments
	Fund of hedge funds	—				—				2,194			2,194
	Hedge funds (a)	—				—				606,462			606,462
	Private equity investments	—				—				13,962			13,962
	Investment fund	—				30,499				—			30,499
	Mutual funds	—				9,857				—			9,857
	Total other investments	—				40,356				622,618			662,974
	Total investments including noncontrolling interests	$	817,937			$	5,335,116			$	629,321		$	6,782,374
	Noncontrolling interest (a)	$	—			$	—			$	(531,403	)	$	(531,403	)
	Redeemable noncontrolling interest (b)	$	(1,976	)		$	—			$	—		$	(1,976	)
	Total investments excluding noncontrolling interests	$	815,961			$	5,335,116			$	97,918		$	6,248,995
	(a)	Included in the hedge funds balance are investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.
	(b)	Included in the total investments balance are investments held by one AlphaCat ILS fund which is consolidated by the Company but in which the Company has an equity interest of less than 100%. The remaining interests are held by third party investors and included in the Consolidated Balance Sheets as redeemable noncontrolling interest.
	At December 31, 2013, the Company’s investments were allocated between Levels 1, 2 and 3 as follows:
		Level 1				Level 2				Level 3			Total
	U.S. government and government agency	$	—			$	1,364,679			$	—		$	1,364,679
	Non-U.S. government and government agency	—				459,068				—			459,068
	U.S. states, municipalities and political subdivisions	—				43,120				—			43,120
	Agency residential mortgage-backed securities	—				311,499				—			311,499
	Non-agency residential mortgage-backed securities	—				15,759				—			15,759
	U.S. corporate	—				1,332,484				—			1,332,484
	Non-U.S. corporate	—				714,325				—			714,325
	Bank loans	—				717,116				—			717,116
	Catastrophe bonds	—				74,551				—			74,551
	Asset-backed securities	—				509,657				—			509,657
	Total fixed maturities	—				5,542,258				—			5,542,258
	Total short-term investments	747,215				4,563				—			751,778
	Other investments
	Fund of hedge funds	—				—				2,303			2,303
	Hedge funds (a)	—				—				561,083			561,083
	Private equity investments	—				—				13,485			13,485
	Investment fund	—				31,629				—			31,629
	Mutual funds	—				9,816				—			9,816
	Total other investments	—				41,445				576,871			618,316
	Total investments including noncontrolling interests	$	747,215			$	5,588,266			$	576,871		$	6,912,352
	Noncontrolling interest (a)	$	—			$	—			$	(489,402	)	$	(489,402	)
	Redeemable noncontrolling interest (b)	$	(18,365	)		$	—			$	—		$	(18,365	)
	Total investments excluding noncontrolling interests	$	728,850			$	5,588,266			$	87,469		$	6,404,585
	(a)	Included in the hedge funds balance are investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.
	(b)	Included in the total investments balance are investments held by two AlphaCat ILS funds which are consolidated by the Company but in which the Company has an equity interest of less than 100%. The remaining interests are held by third party investors and included in the Consolidated Balance Sheets as redeemable noncontrolling interest.
Reconciliation of beginning and ending balances for all Level 3 investments measured at fair value on recurring basis	'
	The following table presents a reconciliation of the beginning and ending balances for all investments measured at fair value on a recurring basis using Level 3 inputs during the three months ended March 31, 2014 and 2013:
			Three Months Ended
			31-Mar-14				31-Mar-13
	Level 3 investments - Beginning of period		$	576,871			$	556,234
	Purchases		—				459
	Sales		(3,589		)		(31,334		)
	Net realized gains		10				40
	Net unrealized gains (losses)		49,326				(1,706		)
	Transfers into Level 3		6,703				—
	Level 3 investments - End of period		$	629,321			$	523,693
	Noncontrolling interest (a)		(531,403		)		(428,087		)
	Level 3 investments excluding noncontrolling interest		$	97,918			$	95,606
	(a)	Includes Level 3 investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.

Investments_in_affiliates_Tabl

Investments in affiliates (Tables)	3 Months Ended
	Mar. 31, 2014
Schedule of Equity Method Investments [Line Items]	'
Schedule of equity method investments	'
	The following table presents the Company's investments in affiliates as at March 31, 2014 and December 31, 2013:
		As at March 31, 2014			As at December 31, 2013
	Investment affiliate	$	39,848		$	34,500
	Operating affiliates	181,759			106,743
	Investments in affiliates	$	221,607		$	141,243
Summary of notes payable to affiliates	'
	The following tables present a reconciliation of the beginning and ending notes payable to operating affiliates for the three months ended March 31, 2014 and 2013:
		AlphaCat 2013			AlphaCat 2014				AlphaCat ILS funds				Total
	As at December 31, 2013	$	223,809		$	—			$	215,463			$	439,272
	Notes payable to operating affiliates recognized on deconsolidation of AlphaCat ILS fund	—			—				178,837				178,837
	Issuance of notes payable to operating affiliates	—			149,707				184,737				334,444
	Redemption of notes payable to operating affiliates	(175,349		)	—				(215,766		)		(391,115		)
	Foreign exchange (gain) loss	(297		)	109				123				(65		)
	As at March 31, 2014	$	48,163		$	149,816			$	363,394			$	561,373
		AlphaCat 2013			AlphaCat ILS funds				Total
	As at December 31, 2012	$	—		$	—			$	—
	Issuance of notes payable to operating affiliates	162,506			131,843				294,349
	Foreign exchange gain	(1,067		)	(2,694		)		(3,761		)
	As at March 31, 2013	$	161,439		$	129,149			$	290,588
Schedule of income attributable to operating affiliate investors	'
	The following table presents the (income) attributable to operating affiliate investors for the three months ended March 31, 2014 and 2013:
		March 31,			March 31,
		2014			2013
	AlphaCat 2013	$	(10,476	)	$	(8,141	)
	AlphaCat 2014	(10,789		)	—
	AlphaCat ILS funds	(10,445		)	(1,936		)
	(Income) attributable to operating affiliate investors	$	(31,710	)	$	(10,077	)
Investment affiliate	'
Schedule of Equity Method Investments [Line Items]	'
Schedule of equity method investments	'
	The following table presents the Company's investment in the Partnership as at March 31, 2014:
		Investment in investment affiliate
		Investment at cost			Voting ownership %			Equity Ownership			Carrying Value
	Aquiline Financial Services Fund II L.P.	$	32,110		—	%		6.7	%		$	39,848
	The following table presents the Company's investment in the Partnership as at December 31, 2013:
		Investment in investment affiliate
		Investment at cost			Voting ownership %			Equity Ownership			Carrying Value
	Aquiline Financial Services Fund II L.P.	$	32,110		—	%		6.7	%		$	34,500
Reconciliation of the beginning and ending non-consolidated affiliate balance	'
	The following table presents a reconciliation of the beginning and ending investment in the Company's investment affiliate balance for the three months ended March 31, 2014 and 2013:
			Three Months Ended
			March 31,			March 31,
			2014			2013
	Investment affiliate, beginning of period		$	34,500		$	15,218
	Capital contributions		—			1,341
	Income from investment affiliate		5,348			1,477
	Investment affiliate, end of period		$	39,848		$	18,036
Operating affiliates	'
Schedule of Equity Method Investments [Line Items]	'
Schedule of equity method investments	'
	The following table presents the Company's investments in AlphaCat Re 2011, AlphaCat Re 2012, AlphaCat 2013, AlphaCat 2014 and the AlphaCat ILS funds in the Consolidated Financial Statements as at March 31, 2014:
		Investment in operating affiliates
		Cost			Voting ownership %			Equity ownership %			Carrying value
	AlphaCat Re 2011	$	4,178		43.7	%		22.3	%		$	4,177
	AlphaCat Re 2012	654			49	%		37.9	%		1,277
	AlphaCat 2013	16,454			40.9	%		19.7	%		15,678
	AlphaCat 2014	22,000			42.3	%		19.6	%		23,593
	AlphaCat ILS funds (a)	133,455			n/a			n/a			137,034
	Total	$	176,741								$	181,759
	(a)	Equity ownerships in the two funds were 9.1% and 49.7% respectively as at March 31, 2014.
	The following table presents the Company's investments in AlphaCat Re 2011, AlphaCat Re 2012, AlphaCat 2013, AlphaCat 2014 and the AlphaCat ILS fund in the Consolidated Financial Statements as at December 31, 2013:
		Investment in operating affiliates
		Cost			Voting ownership %			Equity ownership %			Carrying value
	AlphaCat Re 2011	$	9,882		43.7	%		22.3	%		$	9,809
	AlphaCat Re 2012	654			49	%		37.9	%		1,313
	AlphaCat 2013	45,000			40.9	%		19.7	%		51,744
	AlphaCat 2014	22,000			42.3	%		19.6	%		21,982
	AlphaCat ILS fund	20,000			—	%		9.1	%		21,895
	Total	$	97,536								$	106,743
Reconciliation of the beginning and ending non-consolidated affiliate balance	'
	The following tables present a reconciliation of the beginning and ending investment in operating affiliates for the three months ended March 31, 2014 and 2013:
		AlphaCat Re 2011			AlphaCat Re 2012				AlphaCat 2013				AlphaCat 2014			AlphaCat ILS funds			Total
	As at December 31, 2013	$	9,809		$	1,313			$	51,744			$	21,982		$	21,895		$	106,743
	Return of investment	(5,825		)	—				(37,541		)		—			—			(43,366		)
	Fair value of retained interest on deconsolidation of AlphaCat ILS fund	—			—				—				—			113,455			113,455
	Income (loss) from operating affiliates	193			(36		)		1,475				1,611			1,684			4,927
	As at March 31, 2014	$	4,177		$	1,277			$	15,678			$	23,593		$	137,034		$	181,759
		Three Months Ended March 31, 2013
		AlphaCat Re 2011			AlphaCat Re 2012				AlphaCat 2013				AlphaCat ILS fund			Total
	As at December 31, 2012	$	62,792		$	29,319			$	45,000			$	20,000		$	157,111
	Return of investment	(46,436		)	(3,786		)		—				—			(50,222		)
	Income from operating affiliates	449			1,825				1,100				149			3,523
	As at March 31, 2013	$	16,805		$	27,358			$	46,100			$	20,149		$	110,412

Noncontrolling_interest_Tables

Noncontrolling interest (Tables)	3 Months Ended
	Mar. 31, 2014
Noncontrolling Interest [Abstract]	'
Noncontrolling interest	'
	The following table presents a reconciliation of the beginning and ending balances of redeemable noncontrolling interest and noncontrolling interest for the three months ended March 31, 2014:
		Three Months Ended March 31, 2014
		Redeemable noncontrolling interest			Noncontrolling interest			Total
	As at December 31, 2013	$	86,512		$	497,657		$	584,169
	Income attributable to third parties	232			43,277			43,509
	Adjustment to noncontrolling interest as a result of deconsolidation	(78,354		)	—			(78,354		)
	As at March 31, 2014	$	8,390		$	540,934		$	549,324
	The following table presents a reconciliation of the beginning and ending balances of redeemable noncontrolling interest and noncontrolling interest for the three months ended March 31, 2013:
		Three Months Ended March 31, 2013
		Redeemable noncontrolling interest			Noncontrolling interest			Total
	As at December 31, 2012	$	—		$	434,280		$	434,280
	Issuance of shares	55,690			—			55,690
	Income (loss) attributable to third parties	587			(3,136		)	(2,549		)
	As at March 31, 2013	$	56,277		$	431,144		$	487,421

Derivative_instruments_Tables

Derivative instruments (Tables)	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Location and fair value amount of derivative instruments reported on the balance sheet	'
	The following table summarizes information on the classification and amount of the fair value of derivatives designated as hedging instruments on the consolidated balance sheets at March 31, 2014 and December 31, 2013:
			As at March 31, 2014								As at December 31, 2013
	Derivatives designated as hedging instruments:		Net notional exposure			Asset Derivative at Fair Value (a)			Liability Derivative at Fair Value (a)		Net notional exposure		Asset Derivative at Fair Value (a)		Liability Derivative at Fair Value (a)
	Foreign currency forward contracts		$	151,853		$	3,839		$	477	$	163,576	$	1,167	$	2,313
	Interest rate swap contracts		$	552,263		$	—		$	867	$	552,263	$	—	$	911
	(a)	Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses respectively on the Consolidated Balance Sheets.
Location and amount of gains and losses related to derivative instruments reported on in the income statement	'
	The following table provides the total impact on earnings, recognized in income within foreign exchange gains (losses), relating to the derivative instruments formally designated as fair value hedges along with the impact of the related hedged items for the three months ended March 31, 2014 and 2013:
	Foreign currency forward contracts		Three Months Ended March 31, 2014			Three Months Ended March 31, 2013
	Amount of gain (loss) recognized in income on derivative		$	3,303		$	1,261
	Amount of gain (loss) on hedged item recognized in income attributable to risk being hedged		$	(3,303	)	$	(1,261	)
	Amount of gain (loss) recognized in income on derivative (ineffective portion)		$	—		$	—
	The following table provides the total impact on other comprehensive income (loss) and earnings relating to the derivative instruments formally designated as cash flow hedges along with the impact of the related hedged items for the three months ended March 31, 2014 and 2013:
	Interest rate swap contracts		Three Months Ended March 31, 2014			Three Months Ended March 31, 2013
	Amount of effective portion recognized in other comprehensive income		$	3,208		$	1,608
	Amount of effective portion subsequently reclassified to earnings		$	(3,208	)	$	(1,608	)
	Amount of ineffective portion excluded from effectiveness testing		$	—		$	—

Reserve_for_losses_and_loss_ex1

Reserve for losses and loss expenses (Tables)	3 Months Ended
	Mar. 31, 2014
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]	'
Reserve for losses and loss expenses	'
	The following table represents an analysis of paid and unpaid losses and loss expenses incurred and a reconciliation of the beginning and ending unpaid losses and loss expenses for the three months ended March 31, 2014 and 2013:
			Three Months Ended
			March 31,				March 31,
			2014				2013
	Reserve for losses and loss expenses, beginning of period		$	3,030,399			$	3,517,573
	Losses and loss expenses recoverable		(370,154		)		(439,967		)
	Net reserves for losses and loss expenses, beginning of period		2,660,245				3,077,606
	Increase (decrease) in net losses and loss expenses incurred in respect of losses occurring in:
	Current year		202,086				210,569
	Prior years		(39,415		)		(65,798		)
	Total incurred losses and loss expenses		162,671				144,771
	Less net losses and loss expenses paid in respect of losses occurring in:
	Current year		(7,967		)		(4,838		)
	Prior years		(250,115		)		(255,274		)
	Total net paid losses		(258,082		)		(260,112		)
	Foreign exchange loss (gain)		11,818				(33,826		)
	Net reserve for losses and loss expenses, end of period		2,576,652				2,928,439
	Losses and loss expenses recoverable		348,407				429,252
	Reserve for losses and loss expenses, end of period		$	2,925,059			$	3,357,691
	Incurred losses and loss expenses comprise:
		Three Months Ended
		March 31,				March 31,
		2014				2013
	Gross losses and loss expenses	$	181,975			$	162,411
	Reinsurance recoverable	(19,304		)		(17,640		)
	Net incurred losses and loss expenses	$	162,671			$	144,771

Reinsurance_Tables

Reinsurance (Tables)	3 Months Ended
	Mar. 31, 2014
Reinsurance Disclosures [Abstract]	'
Reinsurance recoverables by reinsurer	'
	Reinsurance recoverables by reinsurer as at March 31, 2014 and December 31, 2013 are as follows:
		March 31, 2014					December 31, 2013
		Reinsurance Recoverable			% of Total		Reinsurance Recoverable		% of Total
	Top 10 reinsurers	$	291,958		75.7	%	$	340,253	75.6	%
	Other reinsurers’ balances > $1 million	85,348			22.2	%	100,784		22.4	%
	Other reinsurers’ balances < $1 million	8,133			2.1	%	9,197		2	%
	Total	$	385,439		100	%	$	450,234	100	%
			March 31, 2014
	Top 10 Reinsurers		Rating	Reinsurance Recoverable			% of Total
	Lloyd's Syndicates		A+	$	66,563		17.3	%
	Everest Re		A+	49,838			12.9	%
	Fully Collateralized		NR	39,120			10.1	%
	Hannover Re		AA-	36,377			9.4	%
	Third Point Reinsurance Ltd		A-	34,081			8.8	%
	Swiss Re		AA-	17,108			4.5	%
	Transatlantic Re		A+	13,449			3.5	%
	XL Re		A+	12,608			3.3	%
	Munich Re		AA-	12,333			3.2	%
	Merrimack Mutual Fire Insurance		A+	10,481			2.7	%
	Total			$	291,958		75.7	%
			December 31, 2013
	Top 10 Reinsurers		Rating	Reinsurance Recoverable			% of Total
	Lloyd's Syndicates		A+	$	73,398		16.3	%
	National Indemnity		AA+	51,037			11.3	%
	Everest Re		A+	48,055			10.7	%
	Hannover Re		AA-	41,483			9.2	%
	Fully Collateralized		NR	36,683			8.1	%
	Third Point Reinsurance Ltd		A-	30,428			6.8	%
	Swiss Re		AA-	20,022			4.5	%
	Transatlantic Re		A+	14,114			3.1	%
	XL Re		A+	12,673			2.8	%
	Munich Re		AA-	12,360			2.8	%
	Total			$	340,253		75.6	%
	NR: Not rated

Share_capital_Tables

Share capital (Tables)	3 Months Ended
	Mar. 31, 2014
Stockholders' Equity Note [Abstract]	'
Summary of common shares issued and outstanding	'
	The following table is a summary of the common shares issued and outstanding:
		Common Shares
	Common shares issued, December 31, 2013	154,488,497
	Restricted share awards vested, net of shares withheld	18,219
	Options exercised	90,019
	Direct issuance of common stock	359
	Common shares issued, March 31, 2014	154,597,094
	Treasury shares, March 31, 2014	(63,810,857	)
	Common shares outstanding, March 31, 2014	90,786,237
		Common Shares
	Common shares issued, December 31, 2012	152,698,191
	Restricted share awards vested, net of shares withheld	130,637
	Restricted share units vested, net of shares withheld	3,796
	Options exercised	128,020
	Direct issuance of common stock	183
	Deferred share units vested, net of shares withheld	2,935
	Common shares issued, March 31, 2013	152,963,762
	Treasury shares, March 31, 2013	(46,681,321	)
	Common shares outstanding, March 31, 2013	106,282,441

Stock_plans_Tables

Stock plans (Tables)	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Options, activity during the period	'
	Activity with respect to options for the three months ended March 31, 2014 was as follows:
		Options			Weighted Average Grant Date Fair Value				Weighted Average Grant Date Exercise Price
	Options outstanding, December 31, 2013	1,572,713			$	6.66			$	18.88
	Options exercised	(90,019	)		4.25				25.46
	Options outstanding, March 31, 2014	1,482,694			$	6.81			$	18.48
	Activity with respect to options for the three months ended March 31, 2013 was as follows:
		Options			Weighted Average Grant Date Fair Value				Weighted Average Grant Date Exercise Price
	Options outstanding, December 31, 2012	1,823,947			$	6.52			$	20.69
	Options regranted (modified)	1,833,414			6.76				19.02
	Options exercised	(128,020	)		3.4				28.98
	Options cancelled (modified)	(1,733,139	)		6.76				20.12
	Options outstanding, March 31, 2013	1,796,202			$	6.75			$	18.95
Restricted shares awards, activity during the period	'
	Activity with respect to unvested restricted share awards for the three months ended March 31, 2014 was as follows:
		Restricted Share Awards			Weighted Average Grant Date Fair Value
	Restricted share awards outstanding, December 31, 2013	2,684,745			$	33.74
	Restricted share awards granted	17,533			36.81
	Restricted share awards vested	(27,353	)		29.31
	Restricted share awards forfeited	(23,094	)		34.57
	Restricted share awards outstanding, March 31, 2014	2,651,831			$	33.8
	Activity with respect to unvested restricted share awards for the three months ended March 31, 2013 was as follows:
		Restricted Share Awards			Weighted Average Grant Date Fair Value
	Restricted share awards outstanding, December 31, 2012	2,170,547			$	29.24
	Restricted share awards granted	22,005			35.63
	Restricted share awards vested	(148,304	)		25.97
	Restricted share awards forfeited	(93,993	)		28.42
	Restricted share awards outstanding, March 31, 2013	1,950,255			$	29.6
Restricted share units, activity during the period	'
	Activity with respect to unvested restricted share units for the three months ended March 31, 2014 was as follows:
		Restricted Share Units			Weighted Average Grant Date Fair Value
	Restricted share units outstanding, December 31, 2013	66,518			$	33.74
	Restricted share units issued in lieu of cash dividends	495			33.74
	Restricted share units outstanding, March 31, 2014	67,013			$	33.74
	Activity with respect to unvested restricted share units for the three months ended March 31, 2013 was as follows:
		Restricted Share Units			Weighted Average Grant Date Fair Value
	Restricted share units outstanding, December 31, 2012	47,238			$	29.61
	Restricted share units vested	(5,468	)		25.27
	Restricted share units issued in lieu of cash dividends	3,020			29.69
	Restricted share units outstanding, March 31, 2013	44,790			$	30.15
Performance share awards, activity during the period	'
	Activity with respect to unvested performance share awards for the three months ended March 31, 2014 was as follows:
		Performance Share Awards			Weighted Average Grant Date Fair Value
	Performance share awards outstanding, December 31, 2013	101,820			$	33.56
	Performance share awards conversion adjustment	(15,344	)		31.38
	Performance share awards outstanding, March 31, 2014	86,476			$	33.95
	Activity with respect to unvested performance share awards for the three months ended March 31, 2013 was as follows:
		Performance Share Awards			Weighted Average Grant Date Fair Value
	Performance share awards outstanding, December 31, 2012	220,845			$	31.81
	Performance share awards forfeited	(128,667	)		32.41
	Performance share awards outstanding, March 31, 2013	92,178			$	30.99
Total share compensation expenses	'
	The breakdown of share compensation expenses by award type was as follows:
		Three Months Ended
		March 31,				March 31,
		2014				2013
	Restricted share awards	$	7,001			$	4,061
	Restricted share units	166				121
	Performance share awards	(20		)		(1,864		)
	Total	$	7,147			$	2,318

Debt_and_financing_arrangement1

Debt and financing arrangements (Tables)	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Schedule of financing structure	'
	The financing structure at March 31, 2014 was:
		Commitment				Issued and outstanding (a)				Drawn
	2006 Junior Subordinated Deferrable Debentures	$	150,000			$	150,000			$	150,000
	2007 Junior Subordinated Deferrable Debentures	200,000				139,800				139,800
	Flagstone 2006 Junior Subordinated Deferrable Debentures	137,904				137,904				137,904
	Flagstone 2007 Junior Subordinated Deferrable Debentures	113,750				113,750				113,750
	Total debentures payable	601,654				541,454				541,454
	2010 Senior Notes due 2040	250,000				250,000				247,225
	Total debentures and senior notes payable	851,654				791,454				788,679
	$400,000 syndicated unsecured letter of credit facility	400,000				—				—
	$525,000 syndicated secured letter of credit facility	525,000				309,422				—
	$200,000 secured bi-lateral letter of credit facility	200,000				18,676				—
	Talbot FAL facility	25,000				25,000				—
	PaCRe senior secured letter of credit facility	10,000				294				—
	AlphaCat Re secured letter of credit facility	30,000				24,800				—
	IPC bi-lateral facility	40,000				19,817				—
	$375,000 Flagstone bi-lateral facility	375,000				292,532				—
	Total credit and other facilities	1,605,000				690,541				—
	Total debt and financing arrangements	$	2,456,654			$	1,481,995			$	788,679
	The financing structure at December 31, 2013 was:
		Commitment				Issued and outstanding (a)				Drawn
	2006 Junior Subordinated Deferrable Debentures	$	150,000			$	150,000			$	150,000
	2007 Junior Subordinated Deferrable Debentures	200,000				139,800				139,800
	Flagstone 2006 Junior Subordinated Deferrable Debentures	137,866				137,866				137,866
	Flagstone 2007 Junior Subordinated Deferrable Debentures	113,750				113,750				113,750
	Total debentures payable	601,616				541,416				541,416
	2010 Senior Notes due 2040	250,000				250,000				247,198
	Total debentures and senior notes payable	851,616				791,416				788,614
	$400,000 syndicated unsecured letter of credit facility	400,000				—				—
	$525,000 syndicated secured letter of credit facility	525,000				358,567				—
	$200,000 secured bi-lateral letter of credit facility	200,000				16,726				—
	Talbot FAL facility	25,000				25,000				—
	PaCRe senior secured letter of credit facility	10,000				294				—
	AlphaCat Re secured letter of credit facility	24,800				24,800				—
	IPC bi-lateral facility	40,000				20,177				—
	$375,000 Flagstone bi-lateral facility	375,000				305,686				—
	Total credit and other facilities	1,599,800				751,250				—
	Total debt and financing arrangements	$	2,451,416			$	1,542,666			$	788,614
	(a)	Indicates utilization of commitment amount, not necessarily drawn borrowings.
Debt Instrument [Line Items]	'
Components of finance expenses	'
	Finance expenses consist of interest on our junior subordinated deferrable debentures, senior notes, the amortization of debt offering costs, fees relating to our credit facilities, bank charges and the costs of FAL as follows:
			Three Months Ended
			March 31,				March 31,
			2014				2013
	2006 Junior Subordinated Deferrable Debentures		$	2,187			$	2,187
	2007 Junior Subordinated Deferrable Debentures		1,809				1,809
	Flagstone 2006 Junior Subordinated Deferrable Debentures		2,223				1,472
	Flagstone 2007 Junior Subordinated Deferrable Debentures		1,750				1,072
	2010 Senior Notes due 2040		5,597				5,597
	Credit facilities		1,559				954
	Bank charges		113				133
	AlphaCat ILS funds fees (a)		677				1,114
	Talbot FAL Facility		(15		)		31
	Total finance expenses		$	15,900			$	14,369
	(a)	Includes finance expenses incurred by AlphaCat Managers, Ltd. in relation to the AlphaCat ILS funds and fund-raising for AlphaCat 2014 and AlphaCat 2013 respectively.
Debt Information At Issuance [Member]	'
Debt Instrument [Line Items]	'
Schedule of Long-term Debt Instruments [Table Text Block]	'
	The following table summarizes the key terms of the Company's senior notes and junior subordinated deferrable debentures as at the issuance date for each placement.
	Description	Issuance date	Commitment			Maturity date	Fixed/Spread			Interest payments due
	2006 Junior Subordinated Deferrable Debentures	June 15, 2006	$	150,000		June 15, 2036	9.069	%	(b)	Quarterly
	Flagstone 2006 Junior Subordinated Deferrable Debentures	August 23, 2006	$	137,904		September 15, 2036	3.54	%	(a)	Quarterly
	2007 Junior Subordinated Deferrable Debentures	June 21, 2007	$	200,000		June 15, 2037	8.48	%	(b)	Quarterly
	Flagstone 2007 Junior Subordinated Deferrable Debentures	June 8, 2007	$	88,750		July 30, 2037	3	%	(a)	Quarterly
	Flagstone 2007 Junior Subordinated Deferrable Debentures	September 20, 2007	$	25,000		September 15, 2037	3.1	%	(a)	Quarterly
	2010 Senior Notes due 2040	January 26, 2010	$	250,000		January 26, 2040	8.875	%	(b)	Semi-annually in arrears
	(a)	Variable interest rate is the three-month LIBOR, reset quarterly, plus spread as noted in the table.
	(b)	Fixed interest rate.
Debt Outstanding [Member]	'
Debt Instrument [Line Items]	'
Schedule of Long-term Debt Instruments [Table Text Block]	'
	The following table summarizes the key terms of the Company's senior notes and junior subordinated deferrable debentures as at March 31, 2014:
	Description	Issuance date	Commitment			Maturity date	Fixed/Spread			Interest payments due
	2006 Junior Subordinated Deferrable Debentures	June 15, 2006	$	150,000		June 15, 2036	5.831	%	(b)	Quarterly
	Flagstone 2006 Junior Subordinated Deferrable Debentures	August 23, 2006	$	137,904		September 15, 2036	6.463	%	(b)	Quarterly
	2007 Junior Subordinated Deferrable Debentures	June 21, 2007	$	200,000		June 15, 2037	5.18	%	(b)	Quarterly
	Flagstone 2007 Junior Subordinated Deferrable Debentures	8-Jun-07	$	88,750		July 30, 2037	5.9	%	(b)	Quarterly
	Flagstone 2007 Junior Subordinated Deferrable Debentures	20-Sep-07	$	25,000		September 15, 2037	5.983	%	(b)	Quarterly
	2010 Senior Notes due 2040	26-Jan-10	$	250,000		January 26, 2040	8.875	%	(a)	Semi-annually in arrears
	(a)	Fixed interest rate.
	(b)	Interest rate has been fixed as a result of interest rate swap contracts entered into by the Company.

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive (Loss) (Tables)	3 Months Ended
	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'
Schedule of changes in accumulated other comprehensive income	'
	Accumulated other comprehensive (loss)
	The changes in accumulated other comprehensive income ("AOCI"), by component for the three months ended March 31, 2014 and 2013 is as follows:
		Three Months Ended March 31, 2014			Three Months Ended March 31, 2013
	Beginning balance, December 31	$	(617	)	$	(2,953	)
	Current period foreign currency translation adjustments	462			(9,785		)
	Ending balance, March 31	$	(155	)	$	(12,738	)

Commitments_and_contingencies_

Commitments and contingencies Commitments and contingencies (Tables)	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Components of required capital	'
	The amounts of cash, investments and letters of credit provided for each year of account as follows:
		2014 Underwriting Year		2013 Underwriting Year
	Talbot FAL facility	$	25,000	$	25,000
	Group funds	450,000		403,700
	Total	$	475,000	$	428,700

Earnings_per_share_Tables

Earnings per share (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Computation of basic and diluted earnings per share	'
	The following table sets forth the computation of basic and earnings per diluted share for the three months ended March 31, 2014 and 2013:
		Three Months Ended
		March 31,			March 31,
		2014			2013
	Basic earnings per share
	Net income	$	205,897		$	220,694
	(Income) loss attributable to noncontrolling interest	(43,509		)	2,549
	Net income available to Validus	162,388			223,243
	Less: Dividends and distributions declared on outstanding warrants	(1,552		)	(14,464		)
	Income available to common shareholders	$	160,836		$	208,779
	Weighted average number of common shares outstanding	93,451,999			107,386,438
	Basic earnings per share available to common shareholders	$	1.72		$	1.94
	Earnings per diluted share
	Net income	$	205,897		$	220,694
	(Income) loss attributable to noncontrolling interest	(43,509		)	2,549
	Net income available to Validus	162,388			223,243
	Less: Dividends and distributions declared on outstanding warrants	—			(14,464		)
	Income available to common shareholders	$	162,388		$	208,779
	Weighted average number of common shares outstanding	93,451,999			107,386,438
	Share equivalents:
	Warrants	2,716,010			—
	Stock options	750,369			1,631,556
	Unvested restricted shares	881,141			1,035,005
	Weighted average number of diluted common shares outstanding	97,799,519			110,052,999
	Earnings per diluted share available to common shareholders	$	1.66		$	1.9

Segment_information_Tables

Segment information (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Summary of results of operating segments and corporate	'
	The following tables summarize the results of our operating segments and "Corporate":
	Three Months Ended March 31, 2014		Validus Re Segment				AlphaCat Segment				Talbot Segment				Corporate & Eliminations				Total
	Underwriting income
	Gross premiums written		$	678,986			$	84,347			$	290,695			$	(42,037	)		$	1,011,991
	Reinsurance premiums ceded		(142,640		)		(3,700		)		(90,605		)		42,037				(194,908		)
	Net premiums written		536,346				80,647				200,090				—				817,083
	Change in unearned premiums		(297,960		)		(49,964		)		13,798				—				(334,126		)
	Net premiums earned		238,386				30,683				213,888				—				482,957
	Underwriting deductions
	Losses and loss expenses		68,155				(7,860		)		102,376				—				162,671
	Policy acquisition costs		39,245				2,980				44,928				(1,504		)		85,649
	General and administrative expenses		18,195				4,128				35,149				16,973				74,445
	Share compensation expenses		2,208				(10		)		2,582				2,367				7,147
	Total underwriting deductions		127,803				(762		)		185,035				17,836				329,912
	Underwriting income (loss)		$	110,583			$	31,445			$	28,853			$	(17,836	)		$	153,045
	Net investment income		18,765				880				4,686				(969		)		23,362
	Other income		6,770				9,497				17				(2,454		)		13,830
	Finance expenses		(3,839		)		(683		)		(26		)		(11,352		)		(15,900		)
	Operating income (loss) before taxes, income from operating affiliates and (income) attributable to operating affiliate investors		132,279				41,139				33,530				(32,611		)		174,337
	Tax benefit (expense)		578				—				130				(668		)		40
	Income from operating affiliates		—				4,927				—				—				4,927
	(Income) attributable to operating affiliate investors		—				(31,710		)		—				—				(31,710		)
	Net operating income (loss)		$	132,857			$	14,356			$	33,660			$	(33,279	)		$	147,594
	Net realized gains on investments		2,446				1,225				69				—				3,740
	Change in net unrealized gains (losses) on investments		11,898				45,872				2,577				(4,654		)		55,693
	Income from investment affiliate		5,348				—				—				—				5,348
	Foreign exchange (losses) gains		(6,176		)		38				(150		)		(190		)		(6,478		)
	Net income (loss)		$	146,373			$	61,491			$	36,156			$	(38,123	)		$	205,897
	Net (income) attributable to noncontrolling interest		—				(43,509		)		—				—				(43,509		)
	Net income (loss) available (attributable) to Validus		$	146,373			$	17,982			$	36,156			$	(38,123	)		$	162,388
	Selected ratios (a):
	Net premiums written / Gross premiums written		79		%		95.6		%		68.8		%						80.7		%
	Losses and loss expenses		28.6		%		(25.6		)%		47.9		%						33.7		%
	Policy acquisition costs		16.5		%		9.7		%		21		%						17.7		%
	General and administrative expenses (b)		8.5		%		13.4		%		17.6		%						16.9		%
	Expense ratio		25		%		23.1		%		38.6		%						34.6		%
	Combined ratio		53.6		%		(2.5		)%		86.5		%						68.3		%
	Total assets		$	5,603,777			$	1,582,014			$	2,975,510			$	94,788			$	10,256,089
	(a)	Ratios are based on net premiums earned.
	(b)	The general and administrative expense ratio includes share compensation expenses.
	Three Months Ended March 31, 2013		Validus Re Segment				AlphaCat Segment				Talbot Segment				Corporate & Eliminations				Total
	Underwriting income
	Gross premiums written		$	747,963			$	96,516			$	293,530			$	(33,249	)		$	1,104,760
	Reinsurance premiums ceded		(125,728		)		—				(94,737		)		33,249				(187,216		)
	Net premiums written		622,235				96,516				198,793				—				917,544
	Change in unearned premiums		(319,101		)		(68,899		)		1,517				—				(386,483		)
	Net premiums earned		303,134				27,617				200,310				—				531,061
	Underwriting deductions
	Losses and loss expenses		73,402				—				71,369				—				144,771
	Policy acquisition costs		51,744				2,638				40,526				(1,297		)		93,611
	General and administrative expenses		29,441				4,037				30,912				15,889				80,279
	Share compensation expenses		1,413				77				1,405				(577		)		2,318
	Total underwriting deductions		156,000				6,752				144,212				14,015				320,979
	Underwriting income (loss)		$	147,134			$	20,865			$	56,098			$	(14,015	)		$	210,082
	Net investment income		23,193				881				4,718				(3,143		)		25,649
	Other income		13,490				6,633				—				(17,438		)		2,685
	Finance expenses		(3,252		)		(1,248		)		(74		)		(9,795		)		(14,369		)
	Operating income (loss) before taxes, income from operating affiliates and (income) attributable to operating affiliate investors		180,565				27,131				60,742				(44,391		)		224,047
	Tax expense (benefit)		1,757				—				(1,054		)		(385		)		318
	Income from operating affiliates		—				3,523				—				—				3,523
	(Income) attributable to operating affiliate investors		—				(10,077		)		—				—				(10,077		)
	Net operating income (loss)		$	182,322			$	20,577			$	59,688			$	(44,776	)		$	217,811
	Net realized gains on investments		1,593				—				128				—				1,721
Change in net unrealized (losses) on investments		(2,193		)		(4,788		)		(256		)		—				(7,237		)
Income from investment affiliate		1,477				—				—				—				1,477
Foreign exchange gains (losses)		11,162				(1,187		)		(3,918		)		865				6,922
Net income (loss)		$	194,361			$	14,602			$	55,642			$	(43,911	)		$	220,694
Net loss attributable to noncontrolling interest		—				2,549				—				—				2,549
Net income (loss) available (attributable) to Validus		$	194,361			$	17,151			$	55,642			$	(43,911	)		$	223,243
Selected ratios (a):
Net premiums written / Gross premiums written		83.2		%		100		%		67.7		%						83.1		%
Losses and loss expenses		24.2		%		0		%		35.6		%						27.3		%
Policy acquisition costs		17.1		%		9.6		%		20.2		%						17.6		%
General and administrative expenses (b)		10.2		%		14.9		%		16.1		%						15.6		%
Expense ratio		27.3		%		24.5		%		36.3		%						33.2		%
Combined ratio		51.5		%		24.5		%		71.9		%						60.5		%
Total assets		$	6,299,481			$	1,189,190			$	3,043,312			$	32,417			$	10,564,400
(a)	Ratios are based on net premiums earned.
(b)	The general and administrative expense ratio includes share compensation expenses.
Gross premiums written allocated to the territory of coverage exposure	'
	The following tables set forth the gross premiums written allocated to the territory of coverage exposure for the periods indicated:
		Three Months Ended March 31, 2014
		Gross Premiums Written
		Validus Re				AlphaCat				Talbot				Eliminations				Total				%
	United States	$	191,868			$	8,698			$	26,311			$	(5,665	)		$	221,212			21.9	%
	Worldwide excluding United States (a)	61,534				7,678				37,182				(4,740		)		101,654				9.9	%
	Australia and New Zealand	12,816				1,019				2,880				(281		)		16,434				1.6	%
	Europe	37,896				1,301				18,791				(2,817		)		55,171				5.5	%
	Latin America and Caribbean	6,934				—				31,239				(3,052		)		35,121				3.5	%
	Japan	159				—				538				(53		)		644				0.1	%
	Canada	2,899				216				3,145				(523		)		5,737				0.6	%
	Rest of the world (b)	53,850				—				18,404				(1,798		)		70,456				7	%
	Sub-total, non United States	176,088				10,214				112,179				(13,264		)		285,217				28.2	%
	Worldwide including United States (a)	105,191				65,435				23,653				(6,646		)		187,633				18.5	%
	Other location non-specific (c)	205,839				—				128,552				(16,462		)		317,929				31.4	%
	Total	$	678,986			$	84,347			$	290,695			$	(42,037	)		$	1,011,991			100	%
		Three Months Ended March 31, 2013
		Gross Premiums Written
		Validus Re				AlphaCat				Talbot				Eliminations				Total				%
	United States	$	236,496			$	17,489			$	20,541			$	(6,864	)		$	267,662			24.2	%
	Worldwide excluding United States (a)	50,308				14,689				39,458				(4,508		)		99,947				9	%
	Australia and New Zealand	25,026				2,183				3,005				(230		)		29,984				2.7	%
	Europe	40,870				1,964				18,311				(2,848		)		58,297				5.3	%
	Latin America and Caribbean	8,418				—				42,000				(3,218		)		47,200				4.3	%
	Japan	737				—				654				(50		)		1,341				0.1	%
	Canada	2,642				318				2,706				(525		)		5,141				0.5	%
	Rest of the world (b)	19,079				—				18,314				(1,403		)		35,990				3.3	%
	Sub-total, non United States	147,080				19,154				124,448				(12,782		)		277,900				25.2	%
	Worldwide including United States (a)	100,540				59,873				19,156				(3,689		)		175,880				15.9	%
	Other location non-specific (c)	263,847				—				129,385				(9,914		)		383,318				34.7	%
	Total	$	747,963			$	96,516			$	293,530			$	(33,249	)		$	1,104,760			100	%
	(a)	Represents risks in two or more geographic zones.
	(b)	Represents risks in one geographic zone.
	(c)	The other locations non-specific category refers to business for which an analysis of exposure by geographic zone is not applicable, such as marine and aerospace risks, since these exposures can span multiple geographic areas and, in some instances, are not fixed locations.

Basis_of_preparation_and_conso1

Basis of preparation and consolidation Basis of preparation and consolidation (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2013
Reclassification From Financing To Operating Cash Flows [Member]	'
Reclassification Adjustment	$19,400
Reclassification From Finance Expenses Into Income Attributable To Operating Affiliate Investors [Member]	'
Reclassification Adjustment	($10,077)

Investments_Gross_unrealized_g

Investments (Gross unrealized gains and losses on fixed maturities) (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Fixed maturities, at amortized cost or cost	$5,263,024		$5,522,853
Short-term investments, at amortized cost or cost	831,679		751,734
Other investments, at amortized cost or cost	632,924		637,728
Total investments including noncontrolling interests	6,727,627		6,912,315
Noncontrolling interest, amortized cost or cost	-512,121	[1]	-512,121	[1]
Redeemable noncontrolling interest, amortized cost or cost	-1,976	[2]	-18,365	[3]
Total investments excluding non-controlling interest, amortized cost or cost	6,213,530		6,381,829
Fixed maturities, gross unrealized gains	40,075		42,756
Short term investments, gross unrealized gains	121		45
Other investments, gross unrealized gains	116,604		76,843
Gross unrealized gains	156,800		119,644
Noncontrolling interest share of unrealized gains other investments	-95,750	[1]	-62,850	[1]
Total investments excluding non-controlling interest, unrealized gains	61,050		56,794
Fixed maturities, gross unrealized losses	-15,499		-23,351
Short term investments, gross unrealized losses	0		-1
Other investments, gross unrealized losses	-86,554		-96,255
Gross unrealized losses	-102,053		-119,607
Noncontrolling interest share of unrealized losses	76,468	[1]	85,569	[1]
Total investments excluding non-controlling interest, unrealized losses	-25,585		-34,038
Total fixed maturities	5,287,600		5,542,258
Total short-term investments	831,800		751,778
Total other investments	662,974		618,316
Total	6,782,374		6,912,352
Noncontrolling interest	-531,403	[1]	-489,402	[1]
Redeemable noncontrolling interest	-1,976	[2]	-18,365	[3]
Total investments excluding noncontrolling interest	6,248,995		6,404,585
U.S. government and government agency	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Fixed maturities, at amortized cost or cost	1,122,846		1,368,826
Fixed maturities, gross unrealized gains	2,241		2,589
Fixed maturities, gross unrealized losses	-4,232		-6,736
Total fixed maturities	1,120,855		1,364,679
Non-U.S. government and government agency	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Fixed maturities, at amortized cost or cost	438,415		454,578
Fixed maturities, gross unrealized gains	5,138		6,511
Fixed maturities, gross unrealized losses	-1,224		-2,021
Total fixed maturities	442,329		459,068
U.S. states, municipalities and political subdivisions	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Fixed maturities, at amortized cost or cost	43,960		42,978
Fixed maturities, gross unrealized gains	626		459
Fixed maturities, gross unrealized losses	-122		-317
Total fixed maturities	44,464		43,120
Agency residential mortgage-backed securities	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Fixed maturities, at amortized cost or cost	293,013		305,450
Fixed maturities, gross unrealized gains	8,201		8,310
Fixed maturities, gross unrealized losses	-1,653		-2,261
Total fixed maturities	299,561		311,499
Non-agency residential mortgage-backed securities	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Fixed maturities, at amortized cost or cost	16,721		16,530
Fixed maturities, gross unrealized gains	254		143
Fixed maturities, gross unrealized losses	-645		-914
Total fixed maturities	16,330		15,759
U.S. corporate	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Fixed maturities, at amortized cost or cost	1,331,550		1,328,960
Fixed maturities, gross unrealized gains	9,315		9,208
Fixed maturities, gross unrealized losses	-3,455		-5,684
Total fixed maturities	1,337,410		1,332,484
Non-U.S. corporate	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Fixed maturities, at amortized cost or cost	699,404		711,581
Fixed maturities, gross unrealized gains	6,460		5,917
Fixed maturities, gross unrealized losses	-1,973		-3,173
Total fixed maturities	703,891		714,325
Bank loans	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Fixed maturities, at amortized cost or cost	640,672		712,859
Fixed maturities, gross unrealized gains	4,678		5,659
Fixed maturities, gross unrealized losses	-1,649		-1,402
Total fixed maturities	643,701		717,116
Catastrophe bonds	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Fixed maturities, at amortized cost or cost	30,500		72,000
Fixed maturities, gross unrealized gains	1,747		2,551
Fixed maturities, gross unrealized losses	0		0
Total fixed maturities	32,247		74,551
Asset-backed securities	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Fixed maturities, at amortized cost or cost	623,631		509,091
Fixed maturities, gross unrealized gains	1,408		1,409
Fixed maturities, gross unrealized losses	-540		-843
Total fixed maturities	624,499		509,657
Commercial mortgage-backed securities	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Fixed maturities, at amortized cost or cost	22,312		'
Fixed maturities, gross unrealized gains	7		'
Fixed maturities, gross unrealized losses	-6		'
Total fixed maturities	22,313		'
Fund of hedge funds	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Other investments, at amortized cost or cost	2,977		3,141
Other investments, gross unrealized gains	138		83
Other investments, gross unrealized losses	-921		-921
Total other investments	2,194		2,303
Hedge funds	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Other investments, at amortized cost or cost	581,369	[1]	584,518	[1]
Other investments, gross unrealized gains	110,058	[1]	71,641	[1]
Other investments, gross unrealized losses	-84,965	[1]	-95,076	[1]
Total other investments	606,462	[1]	561,083	[1]
Private equity investments	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Other investments, at amortized cost or cost	12,068		12,333
Other investments, gross unrealized gains	2,562		1,410
Other investments, gross unrealized losses	-668		-258
Total other investments	13,962		13,485
Investment funds	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Other investments, at amortized cost or cost	30,311		31,537
Other investments, gross unrealized gains	188		92
Other investments, gross unrealized losses	0		0
Total other investments	30,499		31,629
Mutual funds	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Other investments, at amortized cost or cost	6,199		6,199
Other investments, gross unrealized gains	3,658		3,617
Other investments, gross unrealized losses	0		0
Total other investments	$9,857		$9,816
PaCRe funds	'		'
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments	'		'
Noncontrolling Interest, Ownership Percentage by Parent	10.00%		10.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	90.00%		90.00%
[1]	Included in the hedge funds balance are investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.
[2]	Included in the total investments balance are investments held by one AlphaCat ILS fund which is consolidated by the Company but in which the Company has an equity interest of less than 100%. The remaining interests are held by third party investors and included in the Consolidated Balance Sheets as redeemable noncontrolling interest.
[3]	Included in the total investments balance are investments held by two AlphaCat ILS funds which are consolidated by the Company but in which the Company has an equity interest of less than 100%. The remaining interests are held by third party investors and included in the Consolidated Balance Sheets as redeemable noncontrolling interest.

Investments_Fixed_maturities_b

Investments (Fixed maturities by investment rating) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fixed Maturities	'	'
Estimated fair value	$5,287,600	$5,542,258
Percentage of total	100.00%	100.00%
Investment Grade	'	'
Fixed Maturities	'	'
Estimated fair value	4,607,197	4,762,102
Percentage of total	87.10%	85.90%
AAA	'	'
Fixed Maturities	'	'
Estimated fair value	906,648	788,490
Percentage of total	17.10%	14.20%
AA	'	'
Fixed Maturities	'	'
Estimated fair value	2,124,629	2,378,491
Percentage of total	40.20%	42.90%
A	'	'
Fixed Maturities	'	'
Estimated fair value	1,178,357	1,174,562
Percentage of total	22.30%	21.20%
BBB	'	'
Fixed Maturities	'	'
Estimated fair value	397,563	420,559
Percentage of total	7.50%	7.60%
Non Investment Grade	'	'
Fixed Maturities	'	'
Estimated fair value	680,403	780,156
Percentage of total	12.90%	14.10%
BB	'	'
Fixed Maturities	'	'
Estimated fair value	336,265	350,678
Percentage of total	6.40%	6.30%
B	'	'
Fixed Maturities	'	'
Estimated fair value	321,128	390,430
Percentage of total	6.10%	7.00%
CCC	'	'
Fixed Maturities	'	'
Estimated fair value	4,247	4,659
Percentage of total	0.10%	0.10%
CC	'	'
Fixed Maturities	'	'
Estimated fair value	2,602	2,731
Percentage of total	0.00%	0.10%
D/NR	'	'
Fixed Maturities	'	'
Estimated fair value	$16,161	$31,658
Percentage of total	0.30%	0.60%

Investments_Maturity_profile_o

Investments (Maturity profile of fixed maturity investments) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Maturity profile	'	'
Amortized cost or cost	$5,263,024	$5,522,853
Estimated fair value	5,287,600	5,542,258
Fixed maturities trading securities allocated to contractual maturity	'	'
Maturity profile	'	'
Amortized cost or cost	4,307,347	4,691,782
Estimated fair value	4,324,897	4,705,343
Due in one year or less | Fixed maturities trading securities allocated to contractual maturity	'	'
Maturity profile	'	'
Amortized cost or cost	625,774	688,855
Estimated fair value	629,800	692,768
Due after one year through five years | Fixed maturities trading securities allocated to contractual maturity	'	'
Maturity profile	'	'
Amortized cost or cost	3,311,970	3,603,459
Estimated fair value	3,325,578	3,613,847
Due after five years through ten years | Fixed maturities trading securities allocated to contractual maturity	'	'
Maturity profile	'	'
Amortized cost or cost	366,524	396,389
Estimated fair value	366,409	395,633
Due after ten years | Fixed maturities trading securities allocated to contractual maturity	'	'
Maturity profile	'	'
Amortized cost or cost	3,079	3,079
Estimated fair value	3,110	3,095
Asset backed and mortgaged backed securities | No single maturity date	'	'
Maturity profile	'	'
Amortized cost or cost	955,677	831,071
Estimated fair value	$962,703	$836,915

Investments_Components_of_net_

Investments (Components of net investment income) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Net investment income	'	'
Total gross investment income	$25,256	$28,064
Investment expenses	-1,894	-2,415
Net investment income	23,362	25,649
Fixed maturities and short term investments	'	'
Net investment income	'	'
Total gross investment income	23,297	27,531
Cash and cash equivalents	'	'
Net investment income	'	'
Total gross investment income	1,957	533
Securities lending income	'	'
Net investment income	'	'
Total gross investment income	$2	$0

Investments_Realized_and_unrea

Investments (Realized and unrealized gains) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013		Mar. 31, 2014	Dec. 31, 2013
					PaCRe funds	PaCRe funds
Fixed maturities, short-term and other investments and cash equivalents	'		'		'	'
Gross realized gains	$5,296		$10,720		'	'
Gross realized (losses)	-1,556		-8,999		'	'
Net realized gains on investments	3,740		1,721		'	'
Change in net unrealized gains (losses) on investments	55,693		-7,237		'	'
Total net realized gains and change in net unrealized gains (losses) on investments including noncontrolling interest	59,433		-5,516		'	'
Noncontrolling interest	-42,002	[1]	4,651	[1]	'	'
Total net realized gains and change in net unrealized gains (losses) on investments excluding noncontrolling interest	$17,431		($865)		'	'
Noncontrolling Interest, Ownership Percentage by Parent	'		'		10.00%	10.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	'		'		90.00%	90.00%
[1]	Includes change in net unrealized (gains) losses on investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and is included in the Consolidated Statements of Comprehensive Income as net (income) loss attributable to noncontrolling interest.

Investments_Investments_pledge

Investments (Investments pledged as collateral) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Credit facility, commitment	$1,605,000	$1,599,800
Letters of credit issued and outstanding	690,541	751,250
Investments pledged as collateral	1,146,952	1,246,406
$400,000 syndicated unsecured letter of credit facility	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Credit facility, commitment	400,000	400,000
Letters of credit issued and outstanding	0	0
Investments pledged as collateral	0	0
$525,000 syndicated secured letter of credit facility	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Credit facility, commitment	525,000	525,000
Letters of credit issued and outstanding	309,422	358,567
Investments pledged as collateral	499,905	507,620
$200,000 secured bi-lateral letter of credit facility	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Credit facility, commitment	200,000	200,000
Letters of credit issued and outstanding	18,676	16,726
Investments pledged as collateral	35,225	130,256
Talbot FAL Facility	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Credit facility, commitment	25,000	25,000
Letters of credit issued and outstanding	25,000	25,000
Investments pledged as collateral	30,897	30,801
PaCRe Senior secured letter of credit facility	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Credit facility, commitment	10,000	10,000
Letters of credit issued and outstanding	294	294
Investments pledged as collateral	0	0
AlphaCat Re secured letter of credit facility	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Credit facility, commitment	30,000	24,800
Letters of credit issued and outstanding	24,800	24,800
Investments pledged as collateral	30,022	24,806
IPC bi-lateral facility	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Credit facility, commitment	40,000	40,000
Letters of credit issued and outstanding	19,817	20,177
Investments pledged as collateral	96,960	98,465
$375,000 Flagstone bi-lateral facility	'	'
Financial Instruments Owned and Pledged as Collateral [Line Items]	'	'
Credit facility, commitment	375,000	375,000
Letters of credit issued and outstanding	292,532	305,686
Investments pledged as collateral	$453,943	$454,458

Investments_Narrative_Details

Investments (Narrative) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Cash, cash equivalents and investments pledged as collateral	$2,889,470	$2,947,475
Investments held in trust	$2,884,472	$2,942,508
AlphaCat ILS Funds	'	'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Other Investments Number Of Funds	1	2

Fair_value_measurements_Fair_v

Fair value measurements (Fair value hierarchy) (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	$5,287,600		$5,542,258
Short-term investments, at fair value	831,800		751,778
Other investments, at fair value	662,974		618,316
Total	6,782,374		6,912,352
Noncontrolling interest	-531,403	[1]	-489,402	[1]
Redeemable noncontrolling interest share of VIE investments	-1,976	[2]	-18,365	[3]
Total investments excluding noncontrolling interest	6,248,995		6,404,585
U.S. government and government agency	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	1,120,855		1,364,679
Non-US government and government agency	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	442,329		459,068
U.S. states, municipalities and political subdivisions	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	44,464		43,120
Agency residential mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	299,561		311,499
Non-Agency residential mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	16,330		15,759
U.S. corporate	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	1,337,410		1,332,484
Non-U.S. corporate	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	703,891		714,325
Bank loans	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	643,701		717,116
Catastrophe bonds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	32,247		74,551
Asset-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	624,499		509,657
Commercial mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	22,313		'
Fund of hedge funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	2,194		2,303
Hedge funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	606,462	[1]	561,083	[1]
Private equity investments	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	13,962		13,485
Investment funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	30,499		31,629
Mutual funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	9,857		9,816
PaCRe funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Noncontrolling Interest, Ownership Percentage by Parent	10.00%		10.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	90.00%		90.00%
Fair Value, Measurements, Recurring [Member]	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	5,287,600		5,542,258
Short-term investments, at fair value	831,800		751,778
Other investments, at fair value	662,974		618,316
Total	6,782,374		6,912,352
Noncontrolling interest	-531,403	[1]	-489,402	[1]
Redeemable noncontrolling interest share of VIE investments	-1,976	[2]	-18,365	[3]
Total investments excluding noncontrolling interest	6,248,995		6,404,585
Fair Value, Measurements, Recurring [Member] | U.S. government and government agency	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	1,120,855		1,364,679
Fair Value, Measurements, Recurring [Member] | Non-US government and government agency	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	442,329		459,068
Fair Value, Measurements, Recurring [Member] | U.S. states, municipalities and political subdivisions	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	44,464		43,120
Fair Value, Measurements, Recurring [Member] | Agency residential mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	299,561		311,499
Fair Value, Measurements, Recurring [Member] | Non-Agency residential mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	16,330		15,759
Fair Value, Measurements, Recurring [Member] | U.S. corporate	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	1,337,410		1,332,484
Fair Value, Measurements, Recurring [Member] | Non-U.S. corporate	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	703,891		714,325
Fair Value, Measurements, Recurring [Member] | Bank loans	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	643,701		717,116
Fair Value, Measurements, Recurring [Member] | Catastrophe bonds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	32,247		74,551
Fair Value, Measurements, Recurring [Member] | Asset-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	624,499		509,657
Fair Value, Measurements, Recurring [Member] | Commercial mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	22,313		'
Fair Value, Measurements, Recurring [Member] | Fund of hedge funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	2,194		2,303
Fair Value, Measurements, Recurring [Member] | Hedge funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	606,462	[1]	561,083	[1]
Fair Value, Measurements, Recurring [Member] | Private equity investments	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	13,962		13,485
Fair Value, Measurements, Recurring [Member] | Investment funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	30,499		31,629
Fair Value, Measurements, Recurring [Member] | Mutual funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	9,857		9,816
Fair Value, Measurements, Recurring [Member] | Level 1	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Short-term investments, at fair value	817,937		747,215
Other investments, at fair value	0		0
Total	817,937		747,215
Noncontrolling interest	0	[1]	0	[1]
Redeemable noncontrolling interest share of VIE investments	-1,976	[2]	-18,365	[3]
Total investments excluding noncontrolling interest	815,961		728,850
Fair Value, Measurements, Recurring [Member] | Level 1 | U.S. government and government agency	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | Non-US government and government agency	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | U.S. states, municipalities and political subdivisions	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | Agency residential mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | Non-Agency residential mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | U.S. corporate	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | Non-U.S. corporate	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | Bank loans	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | Catastrophe bonds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | Asset-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | Commercial mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		'
Fair Value, Measurements, Recurring [Member] | Level 1 | Fund of hedge funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | Hedge funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	0	[1]	0	[1]
Fair Value, Measurements, Recurring [Member] | Level 1 | Private equity investments	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | Investment funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 1 | Mutual funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 2	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	5,280,897		5,542,258
Short-term investments, at fair value	13,863		4,563
Other investments, at fair value	40,356		41,445
Total	5,335,116		5,588,266
Noncontrolling interest	0	[1]	0	[1]
Redeemable noncontrolling interest share of VIE investments	0	[2]	0	[3]
Total investments excluding noncontrolling interest	5,335,116		5,588,266
Fair Value, Measurements, Recurring [Member] | Level 2 | U.S. government and government agency	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	1,120,855		1,364,679
Fair Value, Measurements, Recurring [Member] | Level 2 | Non-US government and government agency	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	442,329		459,068
Fair Value, Measurements, Recurring [Member] | Level 2 | U.S. states, municipalities and political subdivisions	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	44,464		43,120
Fair Value, Measurements, Recurring [Member] | Level 2 | Agency residential mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	299,561		311,499
Fair Value, Measurements, Recurring [Member] | Level 2 | Non-Agency residential mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	16,330		15,759
Fair Value, Measurements, Recurring [Member] | Level 2 | U.S. corporate	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	1,337,410		1,332,484
Fair Value, Measurements, Recurring [Member] | Level 2 | Non-U.S. corporate	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	703,891		714,325
Fair Value, Measurements, Recurring [Member] | Level 2 | Bank loans	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	643,701		717,116
Fair Value, Measurements, Recurring [Member] | Level 2 | Catastrophe bonds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	25,544		74,551
Fair Value, Measurements, Recurring [Member] | Level 2 | Asset-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	624,499		509,657
Fair Value, Measurements, Recurring [Member] | Level 2 | Commercial mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	22,313		'
Fair Value, Measurements, Recurring [Member] | Level 2 | Fund of hedge funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 2 | Hedge funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	0	[1]	0	[1]
Fair Value, Measurements, Recurring [Member] | Level 2 | Private equity investments	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 2 | Investment funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	30,499		31,629
Fair Value, Measurements, Recurring [Member] | Level 2 | Mutual funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	9,857		9,816
Fair Value, Measurements, Recurring [Member] | Level 3	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	6,703		0
Short-term investments, at fair value	0		0
Other investments, at fair value	622,618		576,871
Total	629,321		576,871
Noncontrolling interest	-531,403	[1]	-489,402	[1]
Redeemable noncontrolling interest share of VIE investments	0	[2]	0	[3]
Total investments excluding noncontrolling interest	97,918		87,469
Percentage Of Fair Value Assets Measured On Recurring Basis	1.60%		1.40%
Fair Value, Measurements, Recurring [Member] | Level 3 | U.S. government and government agency	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 3 | Non-US government and government agency	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 3 | U.S. states, municipalities and political subdivisions	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 3 | Agency residential mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 3 | Non-Agency residential mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 3 | U.S. corporate	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 3 | Non-U.S. corporate	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 3 | Bank loans	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 3 | Catastrophe bonds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	6,703		0
Fair Value, Measurements, Recurring [Member] | Level 3 | Asset-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 3 | Commercial mortgage-backed securities	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Fixed maturities, at fair value	0		'
Fair Value, Measurements, Recurring [Member] | Level 3 | Fund of hedge funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	2,194		2,303
Fair Value, Measurements, Recurring [Member] | Level 3 | Hedge funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	606,462	[1]	561,083	[1]
Fair Value, Measurements, Recurring [Member] | Level 3 | Private equity investments	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	13,962		13,485
Fair Value, Measurements, Recurring [Member] | Level 3 | Investment funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	0		0
Fair Value, Measurements, Recurring [Member] | Level 3 | Mutual funds	'		'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'		'
Other investments, at fair value	$0		$0
[1]	Included in the hedge funds balance are investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.
[2]	Included in the total investments balance are investments held by one AlphaCat ILS fund which is consolidated by the Company but in which the Company has an equity interest of less than 100%. The remaining interests are held by third party investors and included in the Consolidated Balance Sheets as redeemable noncontrolling interest.
[3]	Included in the total investments balance are investments held by two AlphaCat ILS funds which are consolidated by the Company but in which the Company has an equity interest of less than 100%. The remaining interests are held by third party investors and included in the Consolidated Balance Sheets as redeemable noncontrolling interest.

Fair_value_measurements_Level_

Fair value measurements (Level 3 rollforward) (Details) (USD $)

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

In Thousands, unless otherwise specified

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Level 3

Level 3

Level 3

Level 3

PaCRe funds

PaCRe funds

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Other Investments

Other Investments

Reconciliation of beginning and ending balances for all investments measured at fair value on recurring basis

'

'

'

'

'

'

'

'

'

'

Level 3 investments - beginning of period

'

'

'

'

'

'

$576,871

$556,234

'

'

Purchases

'

'

'

'

'

'

0

459

'

'

Sales

'

'

'

'

'

'

-3,589

-31,334

'

'

Realized gains

'

'

'

'

'

'

10

40

'

'

Unrealized losses

'

'

'

'

'

'

49,326

-1,706

'

'

Transfers

'

'

'

'

'

'

6,703

0

'

'

Level 3 investments - end of period

'

'

'

'

'

'

629,321

523,693

'

'

Noncontrolling interest

-531,403

[1]

-489,402

[1]

-531,403

[1]

-489,402

[1]

-531,403

[1]

-489,402

[1]

-531,403

[1]

-428,087

[1]

'

'

Investments excluding noncontrolling interest level three rollforward

'

'

'

'

'

'

$97,918

$95,606

'

'

Noncontrolling Interest, Ownership Percentage by Parent

'

'

'

'

'

'

'

'

10.00%

10.00%

Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners

'

'

'

'

'

'

'

'

90.00%

90.00%

[1]

Included in the hedge funds balance are investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.

Fair_value_measurements_Narrat

Fair value measurements (Narrative) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Other investments, at fair value	$662,974		$618,316
Mutual funds	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Other investments, at fair value	9,857		9,816
Other Investments Number Of Funds	2		'
Hedge funds	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Other investments, at fair value	606,462	[1]	561,083	[1]
Fund of hedge funds	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Other investments, at fair value	2,194		2,303
Investment Time Lag Reporting	'1 month		'
Investments assumed in Flagstone acquisition	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Investment Time Lag Reporting	'3 months		'
Other Investments Number Of Funds	1		'
PaCRe funds	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Noncontrolling Interest, Ownership Percentage by Parent	10.00%		10.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	90.00%		90.00%
Investment Time Lag Reporting	'1 month		'
Other Investments Number Of Funds	4		'
Investment funds	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Other investments, at fair value	30,499		31,629
Other Investments Number Of Funds	1		'
Private equity investments	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Other investments, at fair value	13,962		13,485
Other Investments Number Of Funds	3		'
Fair Value, Measurements, Recurring [Member]	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Other investments, at fair value	662,974		618,316
Fair Value, Measurements, Recurring [Member] | Mutual funds	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Other investments, at fair value	9,857		9,816
Fair Value, Measurements, Recurring [Member] | Hedge funds	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Other investments, at fair value	606,462	[1]	561,083	[1]
Fair Value, Measurements, Recurring [Member] | Fund of hedge funds	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Other investments, at fair value	2,194		2,303
Fair Value, Measurements, Recurring [Member] | Investment funds	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Other investments, at fair value	30,499		31,629
Fair Value, Measurements, Recurring [Member] | Private equity investments	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Other investments, at fair value	$13,962		$13,485
Minimum [Member] | Private equity investments	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Investment Time Lag Reporting	'3 months		'
Maximum | Private equity investments	'		'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'		'
Investment Time Lag Reporting	'6 months		'
[1]	Included in the hedge funds balance are investments held by PaCRe in which the Company has an equity interest of 10%. The remaining 90% interest is held by third party investors and included in the Consolidated Balance Sheets as noncontrolling interest.

Investments_in_affiliates_Summ

Investments in affiliates (Summary of investments in affiliates) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Equity Method Investments [Line Items]	'	'
Investments in affiliates	$221,607	$141,243
Investment affiliate	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Investments in affiliates	39,848	34,500
Operating affiliates	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Investments in affiliates	$181,759	$106,743

Investments_in_affiliates_Inve

Investments in affiliates (Investment affiliate rollforward) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Schedule of Equity Method Investments [Line Items]	'	'
Income from investment affiliate	$5,348	$1,477
Investment affiliate | Aquiline Financial Services Fund LP	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Balance, beginning of period	34,500	15,218
Capital contributions	0	1,341
Income from investment affiliate	5,348	1,477
Balance, end of period	$39,848	$18,036

Investments_in_affiliates_Inve1

Investments in affiliates (Investment affiliate details) (Details) (Investment affiliate, Aquiline Financial Services Fund LP, USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Investment affiliate | Aquiline Financial Services Fund LP	'	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'	'
Investment at cost	$32,110	$32,110	'	'
Voting ownership %	0.00%	0.00%	'	'
Equity ownership %	6.70%	6.70%	'	'
Carrying value	$39,848	$34,500	$18,036	$15,218

Investments_in_affiliates_Oper

Investments in affiliates (Operating affiliates rollforward) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Activity in non-consolidated affiliate balances for the period:	'		'
Fair value of retained interest on deconsolidation of AlphaCat ILS fund	$113,455		'
Income from operating affiliates	4,927		3,523
Operating affiliates	'		'
Activity in non-consolidated affiliate balances for the period:	'		'
Balance, beginning of period	106,743		157,111
Return of investment	-43,366		-50,222
Income from operating affiliates	4,927		3,523
Balance, end of period	181,759		110,412
Operating affiliates | AlphaCat Re 2011	'		'
Activity in non-consolidated affiliate balances for the period:	'		'
Balance, beginning of period	9,809		62,792
Return of investment	-5,825		-46,436
Income from operating affiliates	193		449
Balance, end of period	4,177		16,805
Operating affiliates | AlphaCat Re 2012	'		'
Activity in non-consolidated affiliate balances for the period:	'		'
Balance, beginning of period	1,313		29,319
Return of investment	'		-3,786
Income from operating affiliates	-36		1,825
Balance, end of period	1,277		27,358
Operating affiliates | AlphaCat 2013	'		'
Activity in non-consolidated affiliate balances for the period:	'		'
Balance, beginning of period	51,744		45,000
Return of investment	-37,541		0
Income from operating affiliates	1,475		1,100
Balance, end of period	15,678		46,100
Operating affiliates | AlphaCat 2014	'		'
Activity in non-consolidated affiliate balances for the period:	'		'
Balance, beginning of period	21,982		'
Income from operating affiliates	1,611		'
Balance, end of period	23,593		'
Operating affiliates | AlphaCat ILS Funds	'		'
Activity in non-consolidated affiliate balances for the period:	'		'
Balance, beginning of period	21,895		20,000
Return of investment	'		0
Fair value of retained interest on deconsolidation of AlphaCat ILS fund	113,455		'
Income from operating affiliates	1,684		149
Balance, end of period	$137,034	[1]	$20,149
[1]	Equity ownerships in the two funds were 9.1% and 49.7% respectively as at March 31, 2014.

Investments_in_affiliates_Oper1

Investments in affiliates (Operating affiliates details) (Details) (Operating affiliates, USD $)	Mar. 31, 2014		Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Investment:	'		'	'	'
Investment at cost	$176,741		$97,536	'	'
Carrying value	181,759		106,743	110,412	157,111
AlphaCat Re 2011	'		'	'	'
Investment:	'		'	'	'
Investment at cost	4,178		9,882	'	'
Voting ownership %	43.70%		43.70%	'	'
Equity ownership %	22.30%		22.30%	'	'
Carrying value	4,177		9,809	16,805	62,792
AlphaCat Re 2012	'		'	'	'
Investment:	'		'	'	'
Investment at cost	654		654	'	'
Voting ownership %	49.00%		49.00%	'	'
Equity ownership %	37.90%		37.90%	'	'
Carrying value	1,277		1,313	27,358	29,319
AlphaCat 2013	'		'	'	'
Investment:	'		'	'	'
Investment at cost	16,454		45,000	'	'
Voting ownership %	40.90%		40.90%	'	'
Equity ownership %	19.70%		19.70%	'	'
Carrying value	15,678		51,744	46,100	45,000
AlphaCat 2014	'		'	'	'
Investment:	'		'	'	'
Investment at cost	22,000		22,000	'	'
Voting ownership %	42.30%		42.30%	'	'
Equity ownership %	19.60%		19.60%	'	'
Carrying value	23,593		21,982	'	'
AlphaCat ILS Funds	'		'	'	'
Investment:	'		'	'	'
Investment at cost	133,455	[1]	20,000	'	'
Voting ownership %	'		0.00%	'	'
Equity ownership %	'		9.10%	'	'
Carrying value	$137,034	[1]	$21,895	$20,149	$20,000
[1]	Equity ownerships in the two funds were 9.1% and 49.7% respectively as at March 31, 2014.

Investments_in_affiliates_Note

Investments in affiliates (Notes payable and (income) attributable to operating affiliates) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Schedule of Equity Method Investments [Line Items]	'	'
Notes payable to operating affiliates, beginning of period	$439,272	$0
Notes payable recognized on deconsolidation of AlphaCat ILS fund	178,837	'
Issuance of notes payable to operating affiliates	334,444	294,349
Redemption of notes payable to operating affiliates	-391,115	0
Foreign exchange gain (loss)	-65	-3,761
Notes payable to operating affiliates, end of period	561,373	290,588
Variable interest entity, not primary beneficiary | AlphaCat 2013	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Notes payable to operating affiliates, beginning of period	223,809	0
Notes payable recognized on deconsolidation of AlphaCat ILS fund	0	'
Issuance of notes payable to operating affiliates	0	162,506
Redemption of notes payable to operating affiliates	-175,349	'
Foreign exchange gain (loss)	-297	-1,067
Notes payable to operating affiliates, end of period	48,163	161,439
Variable interest entity, not primary beneficiary | AlphaCat 2014	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Notes payable to operating affiliates, beginning of period	0	'
Issuance of notes payable to operating affiliates	149,707	'
Redemption of notes payable to operating affiliates	0	'
Foreign exchange gain (loss)	109	'
Notes payable to operating affiliates, end of period	149,816	'
Variable interest entity, not primary beneficiary | AlphaCat ILS Funds	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Notes payable to operating affiliates, beginning of period	215,463	0
Notes payable recognized on deconsolidation of AlphaCat ILS fund	178,837	'
Issuance of notes payable to operating affiliates	184,737	131,843
Redemption of notes payable to operating affiliates	-215,766	'
Foreign exchange gain (loss)	123	-2,694
Notes payable to operating affiliates, end of period	$363,394	$129,149

Investments_in_affiliates_Inco

Investments in affiliates (Income attributable to operating affiliates) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Schedule of Equity Method Investments [Line Items]	'	'
(Income) attributable to operating affiliate investors	($31,710)	($10,077)
Variable interest entity, not primary beneficiary | AlphaCat 2013	'	'
Schedule of Equity Method Investments [Line Items]	'	'
(Income) attributable to operating affiliate investors	-10,476	-8,141
Variable interest entity, not primary beneficiary | AlphaCat 2014	'	'
Schedule of Equity Method Investments [Line Items]	'	'
(Income) attributable to operating affiliate investors	-10,789	0
Variable interest entity, not primary beneficiary | AlphaCat ILS Funds	'	'
Schedule of Equity Method Investments [Line Items]	'	'
(Income) attributable to operating affiliate investors	($10,445)	($1,936)

Investments_in_affiliates_Narr

Investments in affiliates (Narrative) (Details) (USD $)

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

In Thousands, unless otherwise specified

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Jan. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

AlphaCat ILS Funds

AlphaCat ILS Funds

Aquiline Financial Services Fund LP

Operating affiliates

Operating affiliates

Operating affiliates

Operating affiliates

Operating affiliates

As investor in third party economic interests

As investor in third party economic interests

As investor in third party economic interests

Equity Method Investments [Member]

Equity Method Investments [Member]

Variable Interest Entity, Primary Beneficiary [Member]

Variable Interest Entity, Primary Beneficiary [Member]

funds

AlphaCat ILS Funds

AlphaCat ILS Funds

AlphaCat ILS Funds

Operating affiliates

AlphaCat ILS Funds

Operating affiliates

funds

AlphaCat ILS Funds

funds

AlphaCat ILS Funds

Schedule of Equity Method Investments [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of Assignor's interest assumed

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

Total capital commitment

'

'

'

'

$50,000

'

'

'

'

'

'

'

'

'

'

'

'

Investment Time Lag Reporting

'

'

'

'

'3 months

'

'

'

'

'

'

'

'

'

'

'

'

Other Investments Number Of Funds

'

'

3

'

'

'

'

'

'

'

'

'

'

1

'

1

'

Third party subscriptions

'

'

'

35,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of retained interest on deconsolidation of AlphaCat ILS fund

113,455

'

'

'

'

'

'

'

113,455

'

'

'

'

'

'

'

'

Deconsolidation, Gain (Loss), Amount

1,372

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity ownership %

'

'

'

'

'

'

'

'

'

9.10%

'

'

'

'

9.10%

'

49.70%

Issuance of notes payable to operating affiliates

334,444

294,349

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Variable Funding Notes, Typical Minimum Duration

'12 months

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Variable Interest Entity Redemption Of Notes Payable To Operating Affiliates

391,115

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Notes Payable Of Operating Affiliates Portion Due to Company

'

'

'

'

'

141,343

'

63,654

'

'

420,030

'

375,618

'

'

'

'

Income Attributable To Operating Affiliates Portion Due to Company

'

'

'

'

'

$6,472

$1,847

'

'

'

$25,238

$8,230

'

'

'

'

'

Noncontrolling_interest_Detail

Noncontrolling interest (Details) (USD $)	3 Months Ended						3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
			PaCRe funds	PaCRe funds	AlphaCat ILS Funds	AlphaCat ILS Funds	Redeemable noncontrolling interest	Redeemable noncontrolling interest	Noncontrolling interest	Noncontrolling interest
			funds		funds	funds
Noncontrolling Interest [Line Items]	'	'	'	'	'	'	'	'	'	'
Other Investments Number Of Funds	'	'	4	'	1	2	'	'	'	'
Noncontrolling Interest, Ownership Percentage by Parent	'	'	10.00%	10.00%	'	'	'	'	'	'
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	'	'	90.00%	90.00%	'	'	'	'	'	'
Redeemable noncontrolling interest and noncontrolling interest, rollforward:	'	'	'	'	'	'	'	'	'	'
Redeemable noncontrolling interest and noncontrolling interest, beginning of period	$584,169	$434,280	'	'	'	'	$86,512	$0	$497,657	$434,280
Income (loss) attributable to third parties	43,509	-2,549	'	'	'	'	232	587	43,277	-3,136
Adjustment to noncontrolling interest as a result of deconsolidation	-78,354	'	'	'	'	'	-78,354	'	0	'
Issuance of shares	'	55,690	'	'	'	'	'	55,690	'	0
Redeemable noncontrolling interest and noncontrolling interest, end of period	$549,324	$487,421	'	'	'	'	$8,390	$56,277	$540,934	$431,144

Amount_and_balance_sheet_locat

(Amount and balance sheet location) (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Designated as hedging instruments | Foreign exchange contracts	'		'
Summary of amount of derivatives designated as hedging instruments	'		'
Net notional exposure	$151,853		$163,576
Designated as hedging instruments | Foreign exchange contracts | Other assets	'		'
Summary of amount of derivatives designated as hedging instruments	'		'
Asset Derivative at Fair Value	3,839	[1]	1,167	[1]
Designated as hedging instruments | Foreign exchange contracts | Accounts payable and accrued expenses	'		'
Summary of amount of derivatives designated as hedging instruments	'		'
Liability Derivative at Fair Value	477	[1]	2,313	[1]
Designated as hedging instruments | Interest rate swap contracts	'		'
Summary of amount of derivatives designated as hedging instruments	'		'
Net notional exposure	552,263		552,263
Designated as hedging instruments | Interest rate swap contracts | Other assets	'		'
Summary of amount of derivatives designated as hedging instruments	'		'
Asset Derivative at Fair Value	0	[1]	0	[1]
Designated as hedging instruments | Interest rate swap contracts | Accounts payable and accrued expenses	'		'
Summary of amount of derivatives designated as hedging instruments	'		'
Liability Derivative at Fair Value	$867	[1]	$911	[1]
Junior Subordinated Deferrable Debentures | Interest rate swap contracts	'		'
Derivatives, Fair Value [Line Items]	'		'
Derivative, Number of Instruments Held	2		'
Flagstone Junior Subordinated Deferrable Debentures | Interest rate swap contracts	'		'
Derivatives, Fair Value [Line Items]	'		'
Derivative, Number of Instruments Held	3		'
Flagstone Junior Subordinated Deferrable Debentures | Cross-currency interest rate swap	'		'
Derivatives, Fair Value [Line Items]	'		'
Derivative, Number of Instruments Held	1		'
[1]	Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses respectively on the Consolidated Balance Sheets.

Derivative_instruments_Amount_

Derivative instruments (Amount included in statement of operations) (Details) (Designated as Hedging Instrument [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Fair value hedge | Foreign exchange contracts | Foreign exchange gains (losses)	'	'
Derivatives designated as fair value hedges and related hedged item	'	'
Amount of gain (loss) recognized in income on derivative	$3,303	$1,261
Amount of gain (loss) on hedged item recognized in income attributable to risk being hedged	-3,303	-1,261
Amount of gain (loss) recognized in income on derivative (ineffective portion)	0	0
Cash flow hedge | Interest rate swap contracts	'	'
Derivative instruments designated as a cash flow hedge	'	'
Amount of ineffective portion excluded from effectiveness testing	0	0
Cash flow hedge | Interest rate swap contracts | Other comprehensive income	'	'
Derivative instruments designated as a cash flow hedge	'	'
Amount of effective portion recognized in other comprehensive income	3,208	1,608
Cash flow hedge | Interest rate swap contracts | Finance expenses	'	'
Derivative instruments designated as a cash flow hedge	'	'
Amount of effective portion subsequently reclassified to earnings	($3,208)	($1,608)

Reserve_for_losses_and_loss_ex2

Reserve for losses and loss expenses (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Reserve for paid losses and unpaid loss expenses	'	'
Reserve for losses and loss expenses, beginning of period	$3,030,399	$3,517,573
Losses and loss expenses recoverable, beginning of period	-370,154	-439,967
Net reserves for losses and loss expenses, beginning of period	2,660,245	3,077,606
Increase (decrease) in net losses and loss expenses incurred in respect of losses occurring in:	'	'
Current year	202,086	210,569
Prior years	-39,415	-65,798
Total incurred losses and loss expenses	162,671	144,771
Less net losses and loss expenses paid in respect of losses occurring in:	'	'
Current year	-7,967	-4,838
Prior years	-250,115	-255,274
Total net paid losses	-258,082	-260,112
Foreign exchange loss (gain)	11,818	-33,826
Net reserve for losses and loss expenses, end of period	2,576,652	2,928,439
Losses and loss expenses recoverable, end of period	348,407	429,252
Reserve for losses and loss expenses, end of period	2,925,059	3,357,691
Components of incurred losses and loss expenses	'	'
Gross losses and loss expenses	181,975	162,411
Reinsurance recoverable	-19,304	-17,640
Net incurred losses and loss expenses	$162,671	$144,771

Reinsurance_Details

Reinsurance (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	$385,439	$450,234
Percentage of reinsurance recoverables	100.00%	100.00%
Reinsurance (Textuals) [Abstract]	'	'
Incurred but not reported recoverable	183,858	196,840
Provision for uncollectible reinsurance relating to losses recoverable	5,427	5,794
A- or better	'	'
Ceded Credit Risk [Line Items]	'	'
Percentage of reinsurance recoverables	98.50%	96.70%
Top 10 reinsurers	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	291,958	340,253
Percentage of reinsurance recoverables	75.70%	75.60%
Top 10 reinsurers | Lloyd's Syndicates | A plus	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	66,563	73,398
Percentage of reinsurance recoverables	17.30%	16.30%
Top 10 reinsurers | Everest Re | A plus	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	49,838	48,055
Percentage of reinsurance recoverables	12.90%	10.70%
Top 10 reinsurers | National Indemnity | AA plus	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	'	51,037
Percentage of reinsurance recoverables	'	11.30%
Top 10 reinsurers | Fully Collateralized | NR	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	39,120	36,683
Percentage of reinsurance recoverables	10.10%	8.10%
Top 10 reinsurers | Hannover Re | AA-	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	36,377	41,483
Percentage of reinsurance recoverables	9.40%	9.20%
Top 10 reinsurers | Third Point Reinsurance Ltd | Standard & Poor's, A- Rating [Member]	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	34,081	30,428
Percentage of reinsurance recoverables	8.80%	6.80%
Top 10 reinsurers | Swiss Re | AA-	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	17,108	20,022
Percentage of reinsurance recoverables	4.50%	4.50%
Top 10 reinsurers | Transatlantic Re | A plus	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	13,449	14,114
Percentage of reinsurance recoverables	3.50%	3.10%
Top 10 reinsurers | XL Re | A plus	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	12,608	12,673
Percentage of reinsurance recoverables	3.30%	2.80%
Top 10 reinsurers | Munich Re | AA-	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	12,333	12,360
Percentage of reinsurance recoverables	3.20%	2.80%
Top 10 reinsurers | Merrimack Mutual Fire Insurance | A plus	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	10,481	'
Percentage of reinsurance recoverables	2.70%	'
Other reinsurers' balances greater than $1 million	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	85,348	100,784
Percentage of reinsurance recoverables	22.20%	22.40%
Other reinsurers' balances less than $1 million	'	'
Ceded Credit Risk [Line Items]	'	'
Reinsurance recoverable	$8,133	$9,197
Percentage of reinsurance recoverables	2.10%	2.00%

Share_capital_Details

Share capital (Details) (USD $)	0 Months Ended		3 Months Ended
In Thousands, except Share data, unless otherwise specified	Feb. 05, 2014	Feb. 06, 2013	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Share Capital (Narrative)	'	'	'	'	'
Common shares, shares authorized	'	'	571,428,571	'	571,428,571
Common shares, par value	'	'	$0.18	'	$0.18
Common stock voting rights	'	'	'one vote per share	'	'
Restriction on percentage of voting power	'	'	9.09%	'	'
Share repurchases	'	'	'	'	'
Stock Repurchase Program, Authorized Amount	'	$500,000	'	'	'
Shares repurchased, cumulative	1,774,436	'	'	'	'
Remaining share repurchase authorization amount	'	'	356,748	'	'
Deferred share units, adjustment factor	'	'	100.00%	'	'
Total outstanding deferred share units	'	'	0	'	0
Cash dividends declared per share	'	'	$0.30	$2.30	'
Summary of common shares issued and outstanding	'	'	'	'	'
Common shares issued, beginning balance	'	'	154,488,497	152,698,191	'
Options exercised (in shares)	'	'	90,019	128,020	'
Direct issuance of common stock	'	'	359	183	'
Common shares issued, ending balance	'	'	154,597,094	152,963,762	'
Shares repurchased, ending balance	'	'	-63,810,857	-46,681,321	'
Common shares outstanding, ending balance	'	'	90,786,237	106,282,441	96,044,312
Common shares	'	'	'	'	'
Share repurchases	'	'	'	'	'
Share repurchase program, cumulative shares repurchased	'	'	62,171,982	'	'
Shares repurchased, cumulative	'	'	$1,917,688	'	'
Cash dividends declared per share	'	'	$0.30	$0.30	'
Common shares | Special dividend declared	'	'	'	'	'
Share repurchases	'	'	'	'	'
Cash dividends declared per share	'	'	'	$2	'
Common share equivalents	'	'	'	'	'
Share repurchases	'	'	'	'	'
Cash dividends declared per share	'	'	'	$0.30	'
Common share equivalents | Special dividend declared	'	'	'	'	'
Share repurchases	'	'	'	'	'
Cash dividends declared per share	'	'	'	$2	'
Warrants	'	'	'	'	'
Share repurchases	'	'	'	'	'
Number of warrants exercised during period	'	'	0	0	'
Class of Warrant or Right, Outstanding	'	'	5,174,114	'	5,296,056
Deferred share units	'	'	'	'	'
Summary of common shares issued and outstanding	'	'	'	'	'
Deferred share units vested, net of shares withheld	'	'	'	2,935	'
Restricted share awards	'	'	'	'	'
Share repurchases	'	'	'	'	'
Vested (in shares)	'	'	27,353	148,304	'
Summary of common shares issued and outstanding	'	'	'	'	'
Vested, net of shares withheld	'	'	18,219	130,637	'
Restricted share units	'	'	'	'	'
Share repurchases	'	'	'	'	'
Vested (in shares)	'	'	'	5,468	'
Summary of common shares issued and outstanding	'	'	'	'	'
Vested, net of shares withheld	'	'	'	3,796	'
Employee director | Deferred share units	'	'	'	'	'
Share repurchases	'	'	'	'	'
Vested (in shares)	'	'	5,039	'	'
Summary of common shares issued and outstanding	'	'	'	'	'
Deferred share units vested, net of shares withheld	'	'	2,935	'	'

Stock_plans_Options_activity_D

Stock plans (Options activity) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Options activities:	'	'
Options outstanding, beginning balance (in shares)	1,572,713	1,823,947
Options regranted (modified) (in shares)	'	1,833,414
Options exercised (in shares)	-90,019	-128,020
Options cancelled (modified) (in shares)	'	-1,733,139
Options outstanding, ending balance (in shares)	1,482,694	1,796,202
Weighted Average Grant Date Fair Value	'	'
Weighted average grant date fair value, beginning balance (in dollars per share)	$6.66	$6.52
Weighted average grant date fair value, options regranted (modified) (in dollars per share)	'	$6.76
Weighted average grant date fair value, options exercised (in dollars per share)	$4.25	$3.40
Weighted average grant date fair value, options cancelled (modified) (in dollars per share)	'	$6.76
Weighted average grant date fair value, ending balance (in dollars per share)	$6.81	$6.75
Weighted Average Grant Date Exercise Price	'	'
Weighted average grant date exercise price, beginning balance (in dollars per share)	$18.88	$20.69
Weighted average grant date exercise price, options regranted (modified) (in dollars per share)	'	$19.02
Weighted average grant date exercise price, options exercised (in dollars per share)	$25.46	$28.98
Weighted average grant date exercise price, options cancelled (modified) (in dollars per share)	'	$20.12
Weighted average grant date exercise price, ending balance (in dollars per share)	$18.48	$18.95

Stock_plans_Other_awards_activ

Stock plans (Other awards activity) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Restricted share awards	'	'
Activities	'	'
Beginning balance (in shares)	2,684,745	2,170,547
Granted (in shares)	17,533	22,005
Vested (in shares)	-27,353	-148,304
Forfeited (in shares)	-23,094	-93,993
Ending balance (in shares)	2,651,831	1,950,255
Weighted average grant date fair value	'	'
Weighted average grant date fair value, beginning balance (in dollars per share)	$33.74	$29.24
Weighted average grant date fair value, granted (in dollars per share)	$36.81	$35.63
Weighted average grant date fair value, vested (in dollars per share)	$29.31	$25.97
Weighted average grant date fair value, forfeited (in dollars per share)	$34.57	$28.42
Weighted average grant date fair value, ending balance (in dollars per share)	$33.80	$29.60
Restricted share units	'	'
Activities	'	'
Beginning balance (in shares)	66,518	47,238
Vested (in shares)	'	-5,468
Issued in lieu of cash dividends (in shares)	495	3,020
Ending balance (in shares)	67,013	44,790
Weighted average grant date fair value	'	'
Weighted average grant date fair value, beginning balance (in dollars per share)	$33.74	$29.61
Weighted average grant date fair value, vested (in dollars per share)	'	$25.27
Weighted average grant date fair value, issued in lieu of cash dividends (in dollars per share)	$33.74	$29.69
Weighted average grant date fair value, ending balance (in dollars per share)	$33.74	$30.15
Performance shares	'	'
Activities	'	'
Beginning balance (in shares)	101,820	220,845
Forfeited (in shares)	'	-128,667
Conversion adjustment (in shares)	-15,344	'
Ending balance (in shares)	86,476	92,178
Weighted average grant date fair value	'	'
Weighted average grant date fair value, beginning balance (in dollars per share)	$33.56	$31.81
Weighted average grant date fair value, forfeited (in dollars per share)	'	$32.41
Weighted average grant date fair value, conversion adjustment (in dollars per share)	$31.38	'
Weighted average grant date fair value, ending balance (in dollars per share)	$33.95	$30.99

Stock_plans_Components_of_shar

Stock plans (Components of share compensation expenses) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Total share compensation expenses	'	'
Share compensation expenses	$7,147	$2,318
Restricted share awards	'	'
Total share compensation expenses	'	'
Share compensation expenses	7,001	4,061
Restricted share units	'	'
Total share compensation expenses	'	'
Share compensation expenses	166	121
Performance shares	'	'
Total share compensation expenses	'	'
Share compensation expenses	($20)	($1,864)

Stock_plans_Text_Details

Stock plans (Text) (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Stock plans (other details)	'	'	'
Number of shares reserved for issuance under the LTIP and STIP	13,126,896	'	'
Remaining number of shares reserved for issuance	1,987,700	'	'
Share compensation expenses	$7,147	$2,318	'
Options	'	'	'
Stock plans (other details)	'	'	'
Life of options	'10 years	'	'
Unrecognized share compensation expenses	0	0	'
Restricted share awards	'	'	'
Stock plans (other details)	'	'	'
Share compensation expenses	7,001	4,061	'
Unrecognized share compensation expenses	62,370	'	69,219
Weighted average period of recognizing share based compensation expenses	'3 years 0 months 0 days	'3 years 2 months 12 days	'
Restricted share units	'	'	'
Stock plans (other details)	'	'	'
Share compensation expenses	166	121	'
Unrecognized share compensation expenses	1,519	'	1,678
Weighted average period of recognizing share based compensation expenses	'3 years 2 months 12 days	'3 years 4 months 24 days	'
Performance shares	'	'	'
Stock plans (other details)	'	'	'
Share compensation expenses	-20	-1,864	'
Unrecognized share compensation expenses	$1,207	'	$1,642
Weighted average period of recognizing share based compensation expenses	'1 year 10 months 24 days	'2 years 0 months 4 days	'
Performance share awards performance period	'3 years	'	'

Debt_and_financing_arrangement2

Debt and financing arrangements (Schedule of finance structure) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]	'	'
Debt instrument, commitment	$851,654	$851,616
Debt instrument, outstanding	791,454	791,416
Debt instrument, drawn	788,679	788,614
Credit facility, commitment	1,605,000	1,599,800
Credit facility, issued and outstanding	690,541	751,250
Total debt and financing arrangements, commitment	2,456,654	2,451,416
Total debt and financing arrangements, outstanding	1,481,995	1,542,666
$400,000 syndicated unsecured letter of credit facility	'	'
Debt Instrument [Line Items]	'	'
Credit facility, commitment	400,000	400,000
Credit facility, issued and outstanding	0	0
$525,000 syndicated secured letter of credit facility	'	'
Debt Instrument [Line Items]	'	'
Credit facility, commitment	525,000	525,000
Credit facility, issued and outstanding	309,422	358,567
$200,000 secured bi-lateral letter of credit facility	'	'
Debt Instrument [Line Items]	'	'
Credit facility, commitment	200,000	200,000
Credit facility, issued and outstanding	18,676	16,726
Talbot FAL facility	'	'
Debt Instrument [Line Items]	'	'
Credit facility, commitment	25,000	25,000
Credit facility, issued and outstanding	25,000	25,000
PaCRe Senior secured letter of credit facility	'	'
Debt Instrument [Line Items]	'	'
Credit facility, commitment	10,000	10,000
Credit facility, issued and outstanding	294	294
AlphaCat Re secured letter of credit facility	'	'
Debt Instrument [Line Items]	'	'
Credit facility, commitment	30,000	24,800
Credit facility, issued and outstanding	24,800	24,800
IPC bi-lateral facility	'	'
Debt Instrument [Line Items]	'	'
Credit facility, commitment	40,000	40,000
Credit facility, issued and outstanding	19,817	20,177
$375,000 Flagstone bi-lateral facility	'	'
Debt Instrument [Line Items]	'	'
Credit facility, commitment	375,000	375,000
Credit facility, issued and outstanding	292,532	305,686
Total debentures payable	'	'
Debt Instrument [Line Items]	'	'
Debt instrument, commitment	601,654	601,616
Debt instrument, outstanding	541,454	541,416
Debt instrument, drawn	541,454	541,416
2006 Junior Subordinated Deferrable Debentures	'	'
Debt Instrument [Line Items]	'	'
Debt instrument, commitment	150,000	150,000
Debt instrument, outstanding	150,000	150,000
Debt instrument, drawn	150,000	150,000
2007 Junior Subordinated Deferrable Debentures	'	'
Debt Instrument [Line Items]	'	'
Debt instrument, commitment	200,000	200,000
Debt instrument, outstanding	139,800	139,800
Debt instrument, drawn	139,800	139,800
Flagstone 2006 Junior Subordinated Deferrable Debentures	'	'
Debt Instrument [Line Items]	'	'
Debt instrument, commitment	137,904	137,866
Debt instrument, outstanding	137,904	137,866
Debt instrument, drawn	137,904	137,866
Flagstone 2007 Junior Subordinated Deferrable Debentures	'	'
Debt Instrument [Line Items]	'	'
Debt instrument, commitment	113,750	113,750
Debt instrument, outstanding	113,750	113,750
Debt instrument, drawn	113,750	113,750
2010 Senior Notes Due 2040	'	'
Debt Instrument [Line Items]	'	'
Debt instrument, commitment	250,000	250,000
Debt instrument, outstanding	250,000	250,000
Debt instrument, drawn	$247,225	$247,198

Debt_and_financing_arrangement3

Debt and financing arrangements (Summary of notes and debentures) (Details) (USD $)

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

In Thousands, unless otherwise specified

2006 Junior Subordinated Deferrable Debentures

2006 Junior Subordinated Deferrable Debentures

Flagstone 2006 Junior Subordinated Deferrable Interest Notes

Flagstone 2006 Junior Subordinated Deferrable Interest Notes

2007 Junior Subordinated Deferrable Debentures

2007 Junior Subordinated Deferrable Debentures

2010 Senior Notes Due 2040

2010 Senior Notes Due 2040

Debt Information At Issuance [Member]

Debt Information At Issuance [Member]

Debt Information At Issuance [Member]

Debt Information At Issuance [Member]

Debt Information At Issuance [Member]

Debt Information At Issuance [Member]

Debt Information At Issuance [Member]

Debt Information At Issuance [Member]

Debt Information At Issuance [Member]

Debt Outstanding [Member]

Debt Outstanding [Member]

Debt Outstanding [Member]

Debt Outstanding [Member]

Debt Outstanding [Member]

Debt Outstanding [Member]

2006 Junior Subordinated Deferrable Debentures

Flagstone 2006 Junior Subordinated Deferrable Interest Notes

Flagstone 2006 Junior Subordinated Deferrable Interest Notes

2007 Junior Subordinated Deferrable Debentures

Flagstone 2007 Due July 30 2037

Flagstone 2007 Due July 30 2037

Flagstone 2007 Debt Due September 15 2037

Flagstone 2007 Debt Due September 15 2037

2010 Senior Notes Due 2040

2006 Junior Subordinated Deferrable Debentures

Flagstone 2006 Junior Subordinated Deferrable Interest Notes

2007 Junior Subordinated Deferrable Debentures

Flagstone 2007 Due July 30 2037

Flagstone 2007 Debt Due September 15 2037

2010 Senior Notes Due 2040

London Interbank Offered Rate (LIBOR) [Member]

London Interbank Offered Rate (LIBOR) [Member]

London Interbank Offered Rate (LIBOR) [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Issuance Date

'

'

'

'

'

'

'

'

'

'

15-Jun-06

23-Aug-06

'

21-Jun-07

8-Jun-07

'

20-Sep-07

'

26-Jan-10

15-Jun-06

23-Aug-06

21-Jun-07

8-Jun-07

20-Sep-07

26-Jan-10

Debt instrument, commitment

$851,654

$851,616

$150,000

$150,000

$137,904

$137,866

$200,000

$200,000

$250,000

$250,000

$150,000

$137,904

'

$200,000

$88,750

'

$25,000

'

$250,000

$150,000

$137,904

$200,000

$88,750

$25,000

$250,000

Debt Instrument, Maturity Date

'

'

'

'

'

'

'

'

'

'

15-Jun-36

15-Sep-36

'

15-Jun-37

30-Jul-37

'

15-Sep-37

'

26-Jan-40

15-Jun-36

15-Sep-36

15-Jun-37

30-Jul-37

15-Sep-37

26-Jan-40

Debt Instrument, Interest Rate, Stated Percentage

'

'

'

'

'

'

'

'

'

'

9.07%

[1]

'

'

8.48%

[1]

'

'

'

'

8.88%

[1]

'

'

'

'

'

8.88%

[1]

Debt Instrument, Basis Spread on Variable Rate

'

'

'

'

'

'

'

'

'

'

'

'

3.54%

[2]

'

'

3.00%

[2]

'

3.10%

[2]

'

'

'

'

'

'

'

Debt Instrument, Interest Rate, Effective Percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.83%

[3]

6.46%

[3]

5.18%

[3]

5.90%

[3]

5.98%

[3]

'

Debt Instrument, Frequency of Periodic Payment

'

'

'

'

'

'

'

'

'

'

'Quarterly

'Quarterly

'

'Quarterly

'Quarterly

'

'Quarterly

'

'Semi-annually in arrears

'Quarterly

'Quarterly

'Quarterly

'Quarterly

'Quarterly

'Semi-annually in arrears

[1]

Fixed interest rate.

[2]

Variable interest rate is the three-month LIBOR, reset quarterly, plus spread as noted in the table.

[3]

Interest rate has been fixed as a result of interest rate swap contracts entered into by the Company.

Debt_and_financing_arrangement4

Debt and financing arrangements (Components of finance expenses) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Debt Instrument [Line Items]	'		'
Financing Interest Expense	$15,900		$14,369
Credit facilities	'		'
Debt Instrument [Line Items]	'		'
Financing Interest Expense	1,559		954
Bank charges	'		'
Debt Instrument [Line Items]	'		'
Financing Interest Expense	113		133
AlphaCat ILS fund fees	'		'
Debt Instrument [Line Items]	'		'
Financing Interest Expense	677	[1]	1,114	[1]
Talbot FAL facility	'		'
Debt Instrument [Line Items]	'		'
Financing Interest Expense	-15		31
2006 Junior Subordinated Deferrable Debentures	'		'
Debt Instrument [Line Items]	'		'
Financing Interest Expense	2,187		2,187
2007 Junior Subordinated Deferrable Debentures	'		'
Debt Instrument [Line Items]	'		'
Financing Interest Expense	1,809		1,809
Flagstone 2006 Junior Subordinated Deferrable Debentures	'		'
Debt Instrument [Line Items]	'		'
Financing Interest Expense	2,223		1,472
Flagstone 2007 Junior Subordinated Deferrable Debentures	'		'
Debt Instrument [Line Items]	'		'
Financing Interest Expense	1,750		1,072
2010 Senior Notes Due 2040	'		'
Debt Instrument [Line Items]	'		'
Financing Interest Expense	$5,597		$5,597
[1]	Includes finance expenses incurred by AlphaCat Managers, Ltd. in relation to the AlphaCat ILS funds and fund-raising for AlphaCat 2014 and AlphaCat 2013 respectively.

Debt_and_financing_arrangement5

Debt and financing arrangements (Text) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Senior Notes and Junior Debentures	'	'
Long-term Debt	$541,454	$541,416
Credit Facilities	'	'
Credit facility, commitment	1,605,000	1,599,800
Credit facility, issued and outstanding	690,541	751,250
Credit Facilities	'	'
Credit Facilities	'	'
Minimum level of consolidated net worth	2,600,000	'
Percent of consolidated net income quarterly increase under covenant	50.00%	'
Percent of any net proceeds from issuance of common shares	50.00%	'
Ratio consolidated total debt to net worth under covenant	'0.35:1.00	'
Four-year syndicated unsecured credit facility	'	'
Credit Facilities	'	'
Credit facility, commitment	400,000	400,000
Credit facility, issued and outstanding	0	0
Letter of credit facility period	'4 years	'
Aggregate commitments, maximum	500,000	'
Line of credit facility initiation date	9-Mar-12	'
Four-year syndicated secured credit facility	'	'
Credit Facilities	'	'
Credit facility, commitment	525,000	525,000
Credit facility, issued and outstanding	309,422	358,567
Letter of credit facility period	'4 years	'
Aggregate commitments, maximum	700,000	'
Line of credit facility initiation date	9-Mar-12	'
Bilateral unsecured letter of credit facility | Terminated Credit Facilities [Member]	'	'
Credit Facilities	'	'
Credit facility, commitment	60,000	'
Letter of credit facility period	'3 years	'
Three year unsecured letter of credit facility | Terminated Credit Facilities [Member]	'	'
Credit Facilities	'	'
Credit facility, commitment	340,000	'
Letter of credit facility period	'3 years	'
Five year secured letter of credit facility	'	'
Credit Facilities	'	'
Credit facility, commitment	525,000	525,000
Credit facility, issued and outstanding	309,422	358,567
Five year secured letter of credit facility | Terminated Credit Facilities [Member]	'	'
Credit Facilities	'	'
Credit facility, commitment	500,000	'
Letter of credit facility period	'5 years	'
Talbot FAL Facility	'	'
Credit Facilities	'	'
Credit facility, commitment	25,000	25,000
Credit facility, issued and outstanding	25,000	25,000
IPC bi-lateral facility	'	'
Credit Facilities	'	'
Credit facility, commitment	40,000	40,000
Credit facility, issued and outstanding	19,817	20,177
$200,000 secured bi-lateral letter of credit facility	'	'
Credit Facilities	'	'
Credit facility, commitment	200,000	200,000
Credit facility, issued and outstanding	18,676	16,726
PaCRe Senior secured letter of credit facility	'	'
Credit Facilities	'	'
Credit facility, commitment	10,000	10,000
Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases	10,000	'
Credit facility, issued and outstanding	294	294
AlphaCat Re secured letter of credit facility	'	'
Credit Facilities	'	'
Credit facility, commitment	30,000	24,800
Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases	24,800	'
Credit facility, issued and outstanding	24,800	24,800
$375,000 Flagstone bi-lateral facility	'	'
Credit Facilities	'	'
Credit facility, commitment	375,000	375,000
Credit facility, issued and outstanding	292,532	305,686
2010 Senior Notes Due 2040	'	'
Senior Notes and Junior Debentures	'	'
Long-term Debt	250,000	'
2010 Senior Notes Due 2040 | Maximum	'	'
Senior Notes and Junior Debentures	'	'
Debt Instrument Redemption Required Notice Period	'60 days	'
2010 Senior Notes Due 2040 | Minimum	'	'
Senior Notes and Junior Debentures	'	'
Debt Instrument Redemption Required Notice Period	'30 days	'
Junior subordinated deeferrable debentures	'	'
Senior Notes and Junior Debentures	'	'
Long-term Debt	$541,454	'
Debt Instrument Redemption Period Duration	'5 years	'

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive (Loss) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'
Balance, beginning of period	($617)	'
Foreign currency translation adjustments	462	-9,785
Balance, end of period	-155	'
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Translation Adjustment [Member]	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'
Balance, beginning of period	-617	-2,953
Foreign currency translation adjustments	462	-9,785
Balance, end of period	($155)	($12,738)

Commitments_and_contingencies_1

Commitments and contingencies (Investment portfolio) (Details) (Concentrations of credit risk)	3 Months Ended
	Mar. 31, 2014
Investment portfolio excluding government and agency securities	'
Concentrations Of Credit Risk [Abstract]	'
Maximum aggregate exposure to single issuer, allowed	3.00%
Aggregate exposure to single issuer, actual	0.90%
Bank loan portfolio	'
Concentrations Of Credit Risk [Abstract]	'
Total investment portfolio, fair value	9.50%
Investment portfolio excluding bank loans	'
Concentrations Of Credit Risk [Abstract]	'
Minimum credit rating of any security purchased	'Baa3/BBB-
Allowable percentage holding in downgraded investments	2.00%
Holding in aggregate market value permitted with written pre-authorization	10.00%
Percent of investment portfolio with a credit rating below the minimum required credit rating of Baa3/BBB-	1.00%

Commitments_and_contingencies_2

Commitments and contingencies (Lloyd's syndicate) (Details)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified	USD ($)	USD ($)	Lloyd's Syndicate 1183	Lloyd's Syndicate 1183	20114 Underwriting year	2013 Underwriting year
			USD ($)	GBP (£)	Lloyd's Syndicate 1183	Lloyd's Syndicate 1183
					USD ($)	USD ($)
Components Of Required Capital [Abstract]	'	'	'	'	'	'
Credit facility, commitment	$1,605,000	$1,599,800	'	'	$25,000	$25,000
Required Capital Group Funds	'	'	'	'	450,000	403,700
Cash, investments and letters of credit amount	'	'	'	'	475,000	428,700
Funds at Lloyd's and Lloyd's Central Fund	'	'	'	'	'	'
Maximum premium levies assessable, percent	'	'	3.00%	3.00%	'	'
Estimated underwriting capacity	'	'	'	625,000	'	'
Exchange rate	'	'	'£1 equals $1.6658	'£1 equals $1.6658	'	'
Maximum premium levies assessable, amount	'	'	$31,234	'	'	'

Commitments_and_contingencies_3

Commitments and contingencies (Aquiline commitment) (Details) (Aquiline Capital Partners II GP Offshore Ltd, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Aquiline Capital Partners II GP Offshore Ltd	'	'
Related Party Transaction [Line Items]	'	'
Total capital commitment	$50,000	'
Remaining capital commitment	$17,890	$17,890

Related_party_transactions_Det

Related party transactions (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Aquiline Capital Partners LLC	'	'	'
Related Party Transaction [Line Items]	'	'	'
Shares owned by related party	3,446,643	'	'
Warrants to purchase shares	2,756,088	'	'
Related Parties Number Of Employees	2	'	'
Group Ark Insurance Holdings Ltd	'	'	'
Related Party Transaction [Line Items]	'	'	'
Gross premiums written	$1,373	$1,795	'
Premiums receivable	181	'	242
Reinsurance premiums ceded	5	4	'
Loss reserves recoverable	2,688	'	3,698
Earned premium adjustments	1,441	719	'
Conning Inc	'	'	'
Related Party Transaction [Line Items]	'	'	'
Investment management fees	56	191	'
Accounts payable and accrued expenses	170	'	283
Aquiline Capital Partners II GP Offshore Ltd	'	'	'
Related Party Transaction [Line Items]	'	'	'
Accounts payable and accrued expenses	0	'	'
Percentage of Assignor's interest assumed	100.00%	'	'
Total capital commitment	50,000	'	'
Partnership fees incurred	0	120	'
Capital contributions	$0	$1,341	'

Earnings_per_share_Details

Earnings per share (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Basic earnings per share	'	'
Net income	$205,897	$220,694
(Income) loss attributable to noncontrolling interest	-43,509	2,549
Net income available to Validus	162,388	223,243
less: Dividends and distributions declared on outstanding warrants	-1,552	-14,464
Income available to common shareholders	160,836	208,779
Weighted average number of common shares outstanding	93,451,999	107,386,438
Basic earnings per share available to common shareholders	$1.72	$1.94
Diluted earnings per share	'	'
Net income	205,897	220,694
(Income) loss attributable to noncontrolling interest	-43,509	2,549
Net income available to Validus	162,388	223,243
less: Dividends and distributions declared on outstanding warrants	0	-14,464
Income available to common shareholders	$162,388	$208,779
Weighted average number of common shares outstanding	93,451,999	107,386,438
Weighted average number of common shares outstanding, diluted	97,799,519	110,052,999
Earnings per diluted share available to common shareholders	$1.66	$1.90
Other details:	'	'
Anti-dilutive securities excluded from the calculation of diluted earnings per share	12,498	104,405
Warrants	'	'
Diluted earnings per share	'	'
Weighted average number diluted shares outstanding adjustment	2,716,010	0
Stock options	'	'
Diluted earnings per share	'	'
Weighted average number diluted shares outstanding adjustment	750,369	1,631,556
Unvested restricted shares	'	'
Diluted earnings per share	'	'
Weighted average number diluted shares outstanding adjustment	881,141	1,035,005

Segment_information_Details

Segment information (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013
	subsidiaries
Segment Reporting Information [Line Items]	'		'		'
Number of wholly owned subsidiaries	3		'		'
Underwriting income	'		'		'
Gross premiums written	$1,011,991		$1,104,760		'
Reinsurance premiums ceded	-194,908		-187,216		'
Net premiums written	817,083		917,544		'
Change in unearned premiums	-334,126		-386,483		'
Net premiums earned	482,957		531,061		'
Underwriting deductions	'		'		'
Losses and loss expenses	162,671		144,771		'
Policy acquisition costs	85,649		93,611		'
General and administrative expenses	74,445		80,279		'
Share compensation expenses	7,147		2,318		'
Total underwriting deductions	329,912		320,979		'
Underwriting income (loss)	153,045		210,082		'
Net investment income	23,362		25,649		'
Other income	13,830		2,685		'
Finance expenses	-15,900		-14,369		'
Operating income (loss) before taxes and income from operating affiliates	174,337		224,047		'
Tax benefit	40		318		'
Income from operating affilates	4,927		3,523		'
(Income) attributable to operating affiliate investors	-31,710		-10,077		'
Net operating income (loss)	147,594		217,811		'
Net realized gains on investments	3,740		1,721		'
Change in net unrealized gains (losses) on investments	55,693		-7,237		'
Income from investment affiliate	5,348		1,477		'
Foreign exchange (losses) gains	-6,478		6,922		'
Net income	205,897		220,694		'
Net (income) loss attributable to noncontrolling interest	-43,509		2,549		'
Net income (loss) available (attributable) to Validus	162,388		223,243		'
Selected ratios:	'		'		'
Net premiums written / Gross premiums written	80.70%	[1]	83.10%	[1]	'
Losses and loss expenses	33.70%	[1]	27.30%	[1]	'
Policy acquisition costs	17.70%	[1]	17.60%	[1]	'
General and administrative expenses	16.90%	[1],[2]	15.60%	[1],[2]	'
Expense ratio	34.60%	[1]	33.20%	[1]	'
Combined ratio	68.30%	[1]	60.50%	[1]	'
Total assets	10,256,089		10,564,400		9,846,432
Operating Segments [Member] | Validus Re Segment	'		'		'
Underwriting income	'		'		'
Gross premiums written	678,986		747,963		'
Reinsurance premiums ceded	-142,640		-125,728		'
Net premiums written	536,346		622,235		'
Change in unearned premiums	-297,960		-319,101		'
Net premiums earned	238,386		303,134		'
Underwriting deductions	'		'		'
Losses and loss expenses	68,155		73,402		'
Policy acquisition costs	39,245		51,744		'
General and administrative expenses	18,195		29,441		'
Share compensation expenses	2,208		1,413		'
Total underwriting deductions	127,803		156,000		'
Underwriting income (loss)	110,583		147,134		'
Net investment income	18,765		23,193		'
Other income	6,770		13,490		'
Finance expenses	-3,839		-3,252		'
Operating income (loss) before taxes and income from operating affiliates	132,279		180,565		'
Tax benefit	578		1,757		'
Income from operating affilates	0		0		'
(Income) attributable to operating affiliate investors	0		0		'
Net operating income (loss)	132,857		182,322		'
Net realized gains on investments	2,446		1,593		'
Change in net unrealized gains (losses) on investments	11,898		-2,193		'
Income from investment affiliate	5,348		1,477		'
Foreign exchange (losses) gains	-6,176		11,162		'
Net income	146,373		194,361		'
Net (income) loss attributable to noncontrolling interest	0		0		'
Net income (loss) available (attributable) to Validus	146,373		194,361		'
Selected ratios:	'		'		'
Net premiums written / Gross premiums written	79.00%	[1]	83.20%	[1]	'
Losses and loss expenses	28.60%	[1]	24.20%	[1]	'
Policy acquisition costs	16.50%	[1]	17.10%	[1]	'
General and administrative expenses	8.50%	[1],[2]	10.20%	[1],[2]	'
Expense ratio	25.00%	[1]	27.30%	[1]	'
Combined ratio	53.60%	[1]	51.50%	[1]	'
Total assets	5,603,777		6,299,481		'
Operating Segments [Member] | AlphaCat Segment	'		'		'
Underwriting income	'		'		'
Gross premiums written	84,347		96,516		'
Reinsurance premiums ceded	-3,700		0		'
Net premiums written	80,647		96,516		'
Change in unearned premiums	-49,964		-68,899		'
Net premiums earned	30,683		27,617		'
Underwriting deductions	'		'		'
Losses and loss expenses	-7,860		0		'
Policy acquisition costs	2,980		2,638		'
General and administrative expenses	4,128		4,037		'
Share compensation expenses	-10		77		'
Total underwriting deductions	-762		6,752		'
Underwriting income (loss)	31,445		20,865		'
Net investment income	880		881		'
Other income	9,497		6,633		'
Finance expenses	-683		-1,248		'
Operating income (loss) before taxes and income from operating affiliates	41,139		27,131		'
Tax benefit	0		0		'
Income from operating affilates	4,927		3,523		'
(Income) attributable to operating affiliate investors	-31,710		-10,077		'
Net operating income (loss)	14,356		20,577		'
Net realized gains on investments	1,225		0		'
Change in net unrealized gains (losses) on investments	45,872		-4,788		'
Income from investment affiliate	0		0		'
Foreign exchange (losses) gains	38		-1,187		'
Net income	61,491		14,602		'
Net (income) loss attributable to noncontrolling interest	-43,509		2,549		'
Net income (loss) available (attributable) to Validus	17,982		17,151		'
Selected ratios:	'		'		'
Net premiums written / Gross premiums written	95.60%	[1]	100.00%	[1]	'
Losses and loss expenses	-25.60%	[1]	0.00%	[1]	'
Policy acquisition costs	9.70%	[1]	9.60%	[1]	'
General and administrative expenses	13.40%	[1],[2]	14.90%	[1],[2]	'
Expense ratio	23.10%	[1]	24.50%	[1]	'
Combined ratio	-2.50%	[1]	24.50%	[1]	'
Total assets	1,582,014		1,189,190		'
Operating Segments [Member] | Talbot Segment	'		'		'
Underwriting income	'		'		'
Gross premiums written	290,695		293,530		'
Reinsurance premiums ceded	-90,605		-94,737		'
Net premiums written	200,090		198,793		'
Change in unearned premiums	13,798		1,517		'
Net premiums earned	213,888		200,310		'
Underwriting deductions	'		'		'
Losses and loss expenses	102,376		71,369		'
Policy acquisition costs	44,928		40,526		'
General and administrative expenses	35,149		30,912		'
Share compensation expenses	2,582		1,405		'
Total underwriting deductions	185,035		144,212		'
Underwriting income (loss)	28,853		56,098		'
Net investment income	4,686		4,718		'
Other income	17		0		'
Finance expenses	-26		-74		'
Operating income (loss) before taxes and income from operating affiliates	33,530		60,742		'
Tax benefit	130		-1,054		'
Income from operating affilates	0		0		'
(Income) attributable to operating affiliate investors	0		0		'
Net operating income (loss)	33,660		59,688		'
Net realized gains on investments	69		128		'
Change in net unrealized gains (losses) on investments	2,577		-256		'
Income from investment affiliate	0		0		'
Foreign exchange (losses) gains	-150		-3,918		'
Net income	36,156		55,642		'
Net (income) loss attributable to noncontrolling interest	0		0		'
Net income (loss) available (attributable) to Validus	36,156		55,642		'
Selected ratios:	'		'		'
Net premiums written / Gross premiums written	68.80%	[1]	67.70%	[1]	'
Losses and loss expenses	47.90%	[1]	35.60%	[1]	'
Policy acquisition costs	21.00%	[1]	20.20%	[1]	'
General and administrative expenses	17.60%	[1],[2]	16.10%	[1],[2]	'
Expense ratio	38.60%	[1]	36.30%	[1]	'
Combined ratio	86.50%	[1]	71.90%	[1]	'
Total assets	2,975,510		3,043,312		'
Corporate And Eliminations [Member]	'		'		'
Underwriting income	'		'		'
Gross premiums written	-42,037		-33,249		'
Reinsurance premiums ceded	42,037		33,249		'
Net premiums written	0		0		'
Change in unearned premiums	0		0		'
Net premiums earned	0		0		'
Underwriting deductions	'		'		'
Losses and loss expenses	0		0		'
Policy acquisition costs	-1,504		-1,297		'
General and administrative expenses	16,973		15,889		'
Share compensation expenses	2,367		-577		'
Total underwriting deductions	17,836		14,015		'
Underwriting income (loss)	-17,836		-14,015		'
Net investment income	-969		-3,143		'
Other income	-2,454		-17,438		'
Finance expenses	-11,352		-9,795		'
Operating income (loss) before taxes and income from operating affiliates	-32,611		-44,391		'
Tax benefit	-668		-385		'
Income from operating affilates	0		0		'
(Income) attributable to operating affiliate investors	0		0		'
Net operating income (loss)	-33,279		-44,776		'
Net realized gains on investments	0		0		'
Change in net unrealized gains (losses) on investments	-4,654		0		'
Income from investment affiliate	0		0		'
Foreign exchange (losses) gains	-190		865		'
Net income	-38,123		-43,911		'
Net (income) loss attributable to noncontrolling interest	0		0		'
Net income (loss) available (attributable) to Validus	-38,123		-43,911		'
Selected ratios:	'		'		'
Total assets	$94,788		$32,417		'
[1]	Ratios are based on net premiums earned.
[2]	The general and administrative expense ratio includes share compensation expenses.

Segment_information_Segment_ge

Segment information (Segment geographic) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	$1,011,991		$1,104,760
Percent of gross premiums written	100.00%		100.00%
United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	221,212		267,662
Percent of gross premiums written	21.90%		24.20%
Worldwide excluding United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	101,654	[1]	99,947	[1]
Percent of gross premiums written	9.90%	[1]	9.00%	[1]
Australia and New Zealand	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	16,434		29,984
Percent of gross premiums written	1.60%		2.70%
Europe	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	55,171		58,297
Percent of gross premiums written	5.50%		5.30%
Latin America and Caribbean	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	35,121		47,200
Percent of gross premiums written	3.50%		4.30%
Japan	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	644		1,341
Percent of gross premiums written	0.10%		0.10%
Canada	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	5,737		5,141
Percent of gross premiums written	0.60%		0.50%
Rest of the world	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	70,456	[2]	35,990	[2]
Percent of gross premiums written	7.00%	[2]	3.30%	[2]
Sub-total, non United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	285,217		277,900
Percent of gross premiums written	28.20%		25.20%
Worldwide including United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	187,633	[1]	175,880	[1]
Percent of gross premiums written	18.50%	[1]	15.90%	[1]
Other location non-specific	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	317,929	[3]	383,318	[3]
Percent of gross premiums written	31.40%	[3]	34.70%	[3]
Operating Segments [Member] | Validus Re Segment	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	678,986		747,963
Operating Segments [Member] | Validus Re Segment | United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	191,868		236,496
Operating Segments [Member] | Validus Re Segment | Worldwide excluding United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	61,534	[1]	50,308	[1]
Operating Segments [Member] | Validus Re Segment | Australia and New Zealand	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	12,816		25,026
Operating Segments [Member] | Validus Re Segment | Europe	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	37,896		40,870
Operating Segments [Member] | Validus Re Segment | Latin America and Caribbean	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	6,934		8,418
Operating Segments [Member] | Validus Re Segment | Japan	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	159		737
Operating Segments [Member] | Validus Re Segment | Canada	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	2,899		2,642
Operating Segments [Member] | Validus Re Segment | Rest of the world	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	53,850	[2]	19,079	[2]
Operating Segments [Member] | Validus Re Segment | Sub-total, non United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	176,088		147,080
Operating Segments [Member] | Validus Re Segment | Worldwide including United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	105,191	[1]	100,540	[1]
Operating Segments [Member] | Validus Re Segment | Other location non-specific	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	205,839	[3]	263,847	[3]
Operating Segments [Member] | AlphaCat Segment	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	84,347		96,516
Operating Segments [Member] | AlphaCat Segment | United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	8,698		17,489
Operating Segments [Member] | AlphaCat Segment | Worldwide excluding United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	7,678	[1]	14,689	[1]
Operating Segments [Member] | AlphaCat Segment | Australia and New Zealand	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	1,019		2,183
Operating Segments [Member] | AlphaCat Segment | Europe	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	1,301		1,964
Operating Segments [Member] | AlphaCat Segment | Latin America and Caribbean	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	0		0
Operating Segments [Member] | AlphaCat Segment | Japan	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	0		0
Operating Segments [Member] | AlphaCat Segment | Canada	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	216		318
Operating Segments [Member] | AlphaCat Segment | Rest of the world	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	0	[2]	0	[2]
Operating Segments [Member] | AlphaCat Segment | Sub-total, non United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	10,214		19,154
Operating Segments [Member] | AlphaCat Segment | Worldwide including United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	65,435	[1]	59,873	[1]
Operating Segments [Member] | AlphaCat Segment | Other location non-specific	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	0	[3]	0	[3]
Operating Segments [Member] | Talbot Segment	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	290,695		293,530
Operating Segments [Member] | Talbot Segment | United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	26,311		20,541
Operating Segments [Member] | Talbot Segment | Worldwide excluding United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	37,182	[1]	39,458	[1]
Operating Segments [Member] | Talbot Segment | Australia and New Zealand	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	2,880		3,005
Operating Segments [Member] | Talbot Segment | Europe	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	18,791		18,311
Operating Segments [Member] | Talbot Segment | Latin America and Caribbean	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	31,239		42,000
Operating Segments [Member] | Talbot Segment | Japan	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	538		654
Operating Segments [Member] | Talbot Segment | Canada	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	3,145		2,706
Operating Segments [Member] | Talbot Segment | Rest of the world	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	18,404	[2]	18,314	[2]
Operating Segments [Member] | Talbot Segment | Sub-total, non United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	112,179		124,448
Operating Segments [Member] | Talbot Segment | Worldwide including United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	23,653	[1]	19,156	[1]
Operating Segments [Member] | Talbot Segment | Other location non-specific	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	128,552	[3]	129,385	[3]
Corporate And Eliminations [Member]	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	-42,037		-33,249
Corporate And Eliminations [Member] | United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	-5,665		-6,864
Corporate And Eliminations [Member] | Worldwide excluding United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	-4,740	[1]	-4,508	[1]
Corporate And Eliminations [Member] | Australia and New Zealand	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	-281		-230
Corporate And Eliminations [Member] | Europe	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	-2,817		-2,848
Corporate And Eliminations [Member] | Latin America and Caribbean	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	-3,052		-3,218
Corporate And Eliminations [Member] | Japan	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	-53		-50
Corporate And Eliminations [Member] | Canada	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	-523		-525
Corporate And Eliminations [Member] | Rest of the world	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	-1,798	[2]	-1,403	[2]
Corporate And Eliminations [Member] | Sub-total, non United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	-13,264		-12,782
Corporate And Eliminations [Member] | Worldwide including United States	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	-6,646	[1]	-3,689	[1]
Corporate And Eliminations [Member] | Other location non-specific	'		'
Gross premiums written allocated to the territory of coverage exposure	'		'
Gross premiums written	($16,462)	[3]	($9,914)	[3]
[1]	Represents risks in two or more geographic zones.
[2]	Represents risks in one geographic zone.
[3]	The other locations non-specific category refers to business for which an analysis of exposure by geographic zone is not applicable, such as marine and aerospace risks, since these exposures can span multiple geographic areas and, in some instances, are not fixed locations.

Subsequent_events_Details

Subsequent events (Details) (USD $)	3 Months Ended					0 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2013	Apr. 30, 2014	Apr. 30, 2014
			Common shares	Common shares	Common share equivalents	Subsequent Event	Subsequent Event
						Common shares	Common share equivalents
Subsequent Event [Line Items]	'	'	'	'	'	'	'
Cash dividends declared per share	$0.30	$2.30	$0.30	$0.30	$0.30	$0.30	$0.30