Validus 10-Q 8 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	6-May-15
Document and Entity Information [Abstract]
Entity Registrant Name	VALIDUS HOLDINGS LTD
Entity Central Index Key	1348259
Document Type	10-Q
Document Period End Date	31-Mar-15
Amendment Flag	FALSE
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	-19
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		84,581,781

Consolidated_Balance_Sheets_Un

Consolidated Balance Sheets (Unaudited) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Assets
Fixed maturities, at fair value (amortized cost: 2015—$5,458,443; 2014—$5,534,494)	$5,484,479		$5,532,731
Short-term investments, at fair value (amortized cost: 2015—$1,183,410; 2014—$1,051,222)	1,183,342	[1]	1,051,074	[1]
Other investments, at fair value (cost: 2015—$908,405; 2014—$879,176)	881,995		813,011
Cash and cash equivalents	471,129		577,240
Restricted cash	186,423		173,003
Total investments and cash	8,207,368		8,147,059
Investments in affiliates	263,332		261,483
Premiums receivable	1,114,102		707,647
Deferred acquisition costs	240,835		161,295
Prepaid reinsurance premiums	192,694		81,983
Securities lending collateral	5,337		470
Loss reserves recoverable	375,882		377,466
Paid losses recoverable	27,034		38,078
Income taxes recoverable	10,597		0
Deferred tax asset	30,847		23,821
Receivable for investments sold	24,803		18,318
Intangible assets	125,508		126,924
Goodwill	195,897		195,897
Accrued investment income	23,230		24,865
Other assets	216,984		164,633
Total assets	11,054,450		10,329,939
Liabilities
Reserve for losses and loss expenses	3,199,362		3,234,394
Unearned premiums	1,452,179		990,564
Reinsurance balances payable	101,426		127,128
Securities lending payable	5,803		936
Deferred tax liability	13,265		5,541
Payable for investments purchased	123,556		68,574
Accounts payable and accrued expenses	177,944		318,245
Notes payable to operating affiliates	919,684		671,465
Senior notes payable	247,333		247,306
Debentures payable	537,561		539,277
Total liabilities	6,778,113		6,203,430
Commitments and contingent liabilities
Redeemable noncontrolling interest	98,777		79,956
Shareholders' equity
Common shares, 571,428,571 authorized, par value $0.175 (Issued: 2015—156,749,783; 2014—155,554,224; Outstanding: 2015—83,634,915; 2014—83,869,845)	27,431		27,222
Treasury shares (2015—73,114,868; 2014—71,684,379)	-12,795		-12,545
Additional paid-in-capital	1,162,485		1,207,493
Accumulated other comprehensive loss	-12,641		-8,556
Retained earnings	2,518,629		2,374,344
Total shareholders' equity available to Validus	3,683,109		3,587,958
Noncontrolling interest	494,451		458,595
Total shareholders' equity	4,177,560		4,046,553
Total liabilities, noncontrolling interests and shareholders’ equity	$11,054,450		$10,329,939
[1]	Included in the short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Assets
Fixed maturities, at amortized cost or cost	$5,458,443		$5,534,494
Short-term investments, at amortized cost or cost	1,183,410	[1]	1,051,222	[1]
Other investments, at amortized cost or cost	$908,405		$879,176
Shareholders' equity
Common shares, shares authorized	571,428,571		571,428,571
Common shares, par value	$0.18		$0.18
Common shares, shares issued	156,749,783		155,554,224
Common shares, shares outstanding	83,634,915		83,869,845
Treasury stock, common shares	73,114,868		71,684,379
[1]	Included in the short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Revenues
Gross premiums written	$1,119,498		$1,011,991
Reinsurance premiums ceded	-190,840		-194,908
Net premiums written	928,658		817,083
Change in unearned premiums	-350,904		-334,126
Net premiums earned	577,754		482,957
Net investment income	31,021		23,362
Net realized gains on investments	4,169		3,740
Change in net unrealized gains on investments	72,204	[1]	55,693	[1]
Income from investment affiliate	2,776		5,348
Other insurance related income and other income	4,832		13,830
Foreign exchange losses	-3,551		-6,478
Total revenues	689,205		578,452
Expenses
Losses and loss expenses	240,929		162,671
Policy acquisition costs	98,636		85,649
General and administrative expenses	85,028		74,445
Share compensation expenses	9,054		7,147
Finance expenses	19,852		15,900
Total expenses	453,499		345,812
Income before taxes, income from operating affiliates and (income) attributable to operating affiliate investors	235,706		232,640
Tax (expense) benefit	-2,565		40
Income from operating affiliates	2,453		4,927
(Income) attributable to operating affiliate investors	-23,206		-31,710
Net income	212,388		205,897
Net (income) attributable to noncontrolling interest	-38,977		-43,509
Net income available to Validus	173,411		162,388
Other comprehensive (loss) income
Change in foreign currency translation adjustments	-3,019		462
Change in minimum pension liability, net of tax	-265		0
Change in fair value of cash flow hedge	-801		0
Other comprehensive (loss) income	-4,085		462
Comprehensive income available to Validus	$169,326		$162,850
Weighted average number of common shares and common share equivalents outstanding
Basic	83,251,243		93,451,999
Diluted	87,583,129		97,799,519
Basic earnings per share available to common shareholders	$2.07		$1.72
Earnings per diluted share available to common shareholders	$1.98		$1.66
Cash dividends declared per share	$0.32		$0.30
[1]	Includes the change in net unrealized gains 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 loss (income) attributable to noncontrolling interest.

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, 2013		$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 (loss) income	462
Dividends						-29,718
Net income	205,897					205,897
Net (income) attributable to noncontrolling interest	-43,509					-43,509
Total shareholders' equity at Mar. 31, 2014	4,189,998
Noncontrolling interest at Mar. 31, 2014	540,934
Balance - End of period at Mar. 31, 2014	3,649,064	27,055	-11,167	1,490,652	-155	2,142,679
Balance - Beginning of period at Dec. 31, 2014	3,587,958	27,222	-12,545	1,207,493	-8,556	2,374,344
Common shares issued, net		209		3,796
Repurchase of common shares			-250	-57,858
Share compensation expenses				9,054
Other comprehensive (loss) income	-4,085
Dividends						-29,126
Net income	212,388					212,388
Net (income) attributable to noncontrolling interest	-38,977					-38,977
Total shareholders' equity at Mar. 31, 2015	4,177,560
Noncontrolling interest at Mar. 31, 2015	494,451
Balance - End of period at Mar. 31, 2015	$3,683,109	$27,431	($12,795)	$1,162,485	($12,641)	$2,518,629

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Cash flows provided by (used in) operating activities
Net income	$212,388		$205,897
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Share compensation expenses	9,054		7,147
Gain on deconsolidation of subsidiary	0		-1,372
Amortization of discount on senior notes	27		27
Income from investment affiliate	-2,776		-5,348
Net realized gains on investments	-4,169		-3,740
Change in net unrealized gains on investments	-72,204	[1]	-55,693	[1]
Amortization of intangible assets	1,416		1,040
Income from operating affiliates	-2,453		-4,927
Foreign exchange losses (gains) included in net income	8,788		-4,347
Amortization of premium on fixed maturities	6,747		4,117
Change in:
Premiums receivable	-409,847		-393,543
Deferred acquisition costs	-79,540		-68,098
Prepaid reinsurance premiums	-110,711		-115,112
Loss reserves recoverable	-205		21,832
Paid losses recoverable	10,976		43,054
Income taxes recoverable	-10,759		0
Deferred tax asset	-7,132		0
Accrued investment income	1,558		2,366
Other assets	-53,575		13,558
Reserve for losses and loss expenses	-22,700		-105,842
Unearned premiums	461,615		449,238
Reinsurance balances payable	-24,646		57,765
Deferred tax liability	7,585		3,551
Accounts payable and accrued expenses	-147,978		-95,997
Net cash used in operating activities	-228,541		-44,427
Cash flows provided by (used in) investing activities
Proceeds on sales of investments	1,190,559		984,356
Proceeds on maturities of investments	93,732		124,716
Purchases of fixed maturities	-1,163,707		-782,290
Purchases of short-term investments, net	-133,104		-107,437
(Purchases) sales of other investments, net	-29,291		7,059
Increase in securities lending collateral	-4,867		-1,485
Redemption in operating affiliates	24,150		43,366
(Increase) decrease in restricted cash	-13,420		91,274
Net cash (used in) provided by investing activities	-56,718		359,559
Cash flows provided by (used in) financing activities
Proceeds on issuance of notes payable to operating affiliates	621,864		154,028
Repayments on notes payable to operating affiliates	-365,883		-184,628
Issuance of common shares, net	4,005		2,030
Purchases of common shares under share repurchase program	-58,108		-197,339
Dividends paid	-28,217		-29,330
Increase in securities lending payable	4,867		1,485
Third party investment in redeemable noncontrolling interest	15,700		0
Third party redemption of redeemable noncontrolling interest	0		-10,496
Net cash provided by (used in) financing activities	194,228		-264,250
Effect of foreign currency rate changes on cash and cash equivalents	-15,080		4,890
Net (decrease) increase in cash	-106,111		55,772
Cash and cash equivalents - beginning of period	577,240		734,148
Cash and cash equivalents - end of period	471,129		789,920
Taxes paid during the period	7,187		152
Interest paid during the period	19,188		19,174
Operating affiliates
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Income from operating affiliates	-2,453		-4,927
Cash flows provided by (used in) investing activities
Investments in affiliates	-1,070		0
Investment affiliate
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Income from investment affiliate	-2,776		-5,348
Cash flows provided by (used in) investing activities
Investments in affiliates	($19,700)		$0
[1]	Includes the change in net unrealized gains 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 loss (income) attributable to noncontrolling interest.

Basis_of_preparation_and_conso

Basis of preparation and consolidation	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation and consolidation	Basis of preparation and consolidation
	These unaudited Consolidated Financial Statements (the "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, 2014, as filed with the U.S. Securities and Exchange Commission (the "SEC").
	In the opinion of management, these 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. The Consolidated Statement of Cash Flows for the three months ended March 31, 2014 includes a revision to increase net cash provided by investing activities by $94,768. There are no changes to the sub-totals of net cash used in operating activities, financing activities or the effect of foreign currency rate changes on cash and cash equivalents. This revision resulted in an increase in net cash of $94,768 for the three months ended March 31, 2014.
	The effect of this revision does not impact any per-share amounts or other components of equity or net assets in the statement of financial position in the prior period presented. The Company does not believe this revision is material to the prior period. The Company has revised these prior period amounts to provide comparability with current period cash flows. 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, 2015
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent accounting pronouncements	Recent accounting pronouncements
	Recently Issued Accounting Standards Not Yet Adopted
	In May 2014, the FASB issued Accounting Standard Update No. 2014-09, “Revenue from Contracts with Customers” (ASU 2014-09). The guidance in this Update affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets, unless those contracts are within the scope of other standards (for example, insurance contracts or lease contracts). The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The amendments in this Update are effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. Earlier adoption is not permitted. The Company is currently evaluating the impact of this guidance on the Company’s Consolidated Financial Statements.
	In February 2015, the FASB issued Accounting Standard Update 2015-02, “Consolidation (Topic 810) Amendments to the Consolidation Analysis” (ASU 2015-02). The amendments in this update modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities (VIEs) or voting interest entities. The amendment also eliminates the presumption that a general partner should consolidate a limited partnership and affects the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships. The amendment also provides a scope exception from consolidation guidance for reporting entities with interests in legal entities that are required to comply with or operate in accordance with requirements that are similar to those in Rule 2a-7 of the Investment Company Act of 1940 for registered money market funds. The amendments in this Update are effective for interim and annual periods beginning after December 15, 2015. Early adoption is permitted. The Company is currently evaluating the impact of this guidance; however, it could have a material impact on the Company’s Consolidated Financial Statements.
	In April 2015, the FASB issued Accounting Standard Update 2015-03, “Interest - Imputation of Interest (Subtopic 835-30) - Simplifying the Presentation of Debt Issuance Costs” (ASU 2015-03). The amendments in this Update simplify the presentation of debt issuance costs and require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this Update. The amendments in this Update are effective for financial statements issued for fiscal years beginning after December 15, 2015 and interim periods within those fiscal years. Early adoption of the amendments in this Update is permitted for financial statements that have not been previously issued. The Company is currently evaluating the impact of this guidance; however, it will not have a material impact on the Company's Consolidated Financial Statements.

Investments

Investments	3 Months Ended
	Mar. 31, 2015
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, 2015 were as follows:
		Amortized Cost or Cost			Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
	U.S. government and government agency	$	768,112		$	3,867			$	(278	)		$	771,701
	Non-U.S. government and government agency	244,372			1,771				(2,610		)		243,533
	U.S. states, municipalities and political subdivisions	347,348			3,749				(254		)		350,843
	Agency residential mortgage-backed securities	522,951			11,725				(442		)		534,234
	Non-agency residential mortgage-backed securities	32,393			360				(645		)		32,108
	U.S. corporate	1,436,724			10,929				(1,507		)		1,446,146
	Non-U.S. corporate	509,705			4,827				(3,951		)		510,581
	Bank loans	464,761			1,417				(4,838		)		461,340
	Catastrophe bonds	129,711			556				(3,050		)		127,217
	Asset-backed securities	702,298			2,755				(788		)		704,265
	Commercial mortgage-backed securities	300,068			2,828				(385		)		302,511
	Total fixed maturities	5,458,443			44,784				(18,748		)		5,484,479
	Total short-term investments (a)	1,183,410			11				(79		)		1,183,342
	Other investments
	Fund of hedge funds	1,915			76				(921		)		1,070
	Preferred stock	2,945			60				—				3,005
	Hedge funds (b)	595,753			95,124				(129,559		)		561,318
	Private equity investments	48,140			5,831				(1,119		)		52,852
	Investment funds	253,453			561				—				254,014
	Mutual funds	6,199			3,537				—				9,736
	Total other investments	908,405			105,189				(131,599		)		881,995
	Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	7,550,258		$	149,984			$	(150,426	)		$	7,549,816
	Assets managed on behalf of operating affiliates (a)	(751,473		)	—				—				(751,473		)
	Catastrophe bonds	(129,711		)	(556		)		3,050				(127,217		)
	Noncontrolling interest (b)	(525,330		)	(79,346		)		116,603				(488,073		)
	Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	6,143,744		$	70,082			$	(30,773	)		$	6,183,053
	(a)	Included in the short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.
	(b)	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.
	The amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments at December 31, 2014 were as follows:
		Amortized Cost or Cost			Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
	U.S. government and government agency	$	759,232		$	1,755			$	(901	)		$	760,086
	Non-U.S. government and government agency	279,493			1,215				(1,980		)		278,728
	U.S. states, municipalities and political subdivisions	448,668			1,780				(825		)		449,623
	Agency residential mortgage-backed securities	520,685			9,697				(1,151		)		529,231
	Non-agency residential mortgage-backed securities	37,954			369				(516		)		37,807
	U.S. corporate	1,500,963			3,960				(5,217		)		1,499,706
	Non-U.S. corporate	564,386			2,765				(3,989		)		563,162
	Bank loans	457,537			200				(8,733		)		449,004
	Catastrophe bonds	75,822			768				(926		)		75,664
	Asset-backed securities	647,422			1,250				(1,190		)		647,482
	Commercial mortgage-backed securities	242,332			598				(692		)		242,238
	Total fixed maturities	5,534,494			24,357				(26,120		)		5,532,731
	Total short-term investments (a)	1,051,222			13				(161		)		1,051,074
	Other investments
	Fund of hedge funds	2,570			125				(920		)		1,775
	Preferred stock	6,535			—				(201		)		6,334
	Hedge funds (b)	570,371			60,792				(134,203		)		496,960
	Private equity investments	48,995			4,987				(611		)		53,371
	Investment funds	244,506			437				(111		)		244,832
	Mutual funds	6,199			3,540				—				9,739
	Total other investments	879,176			69,881				(136,046		)		813,011
	Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	7,464,892		$	94,251			$	(162,327	)		$	7,396,816
	Assets managed on behalf of operating affiliates (a)	(696,924		)	—				—				(696,924		)
	Catastrophe bonds	(75,822		)	(768		)		926				(75,664		)
	Noncontrolling interest (b)	(502,830		)	(48,446		)		120,782				(430,494		)
	Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	6,189,316		$	45,037			$	(40,619	)		$	6,193,734
	(a)	Included in the short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.
	(b)	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.
	The following table sets forth certain information regarding the investment ratings of the Company’s fixed maturities portfolio as at March 31, 2015 and December 31, 2014.
	March 31, 2015						December 31, 2014
	Estimated Fair Value			% of Total			Estimated Fair Value				% of Total
AAA	$	2,473,674		45.1	%		$	2,494,239			45.1	%
AA	660,150			12	%		848,226				15.4	%
A	1,087,156			19.8	%		1,086,091				19.6	%
BBB	570,464			10.4	%		505,208				9.1	%
Total investment-grade fixed maturities	4,791,444			87.3	%		4,933,764				89.2	%
BB	307,561			5.6	%		362,972				6.6	%
B	247,983			4.5	%		145,240				2.6	%
CCC	4,365			0.1	%		12,733				0.2	%
CC	3,286			0.1	%		3,926				0.1	%
C	—			—	%		1,344				—	%
D/NR	129,840			2.4	%		72,752				1.3	%
Total non-investment grade fixed maturities	693,035			12.7	%		598,967				10.8	%
Total fixed maturities	$	5,484,479		100	%		$	5,532,731			100	%
The amortized cost and estimated fair value amounts for fixed maturities held at March 31, 2015 and December 31, 2014 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, 2015							December 31, 2014
	Amortized Cost			Estimated Fair Value				Amortized Cost				Estimated Fair Value
Due in one year or less	$	291,651		$	292,276			$	312,843			$	313,248
Due after one year through five years	2,921,246			2,928,600				3,163,225				3,159,200
Due after five years through ten years	571,599			572,771				497,175				491,870
Due after ten years	116,237			117,716				112,858				111,655
	3,900,733			3,911,363				4,086,101				4,075,973
Asset-backed and mortgage-backed securities	1,557,710			1,573,116				1,448,393				1,456,758
Total fixed maturities	$	5,458,443		$	5,484,479			$	5,534,494			$	5,532,731
(b)	Net investment income
Net investment income was derived from the following sources:
	Three Months Ended
	March 31, 2015			March 31, 2014
Fixed maturities and short-term investments	$	29,239		$	23,297
Other investments	3,188			—
Restricted cash and cash and cash equivalents	435			1,957
Securities lending income	3			2
Total gross investment income	32,865			25,256
Investment expenses	(1,844		)	(1,894		)
Total net investment income	$	31,021		$	23,362
Net investment income from other investments includes distributed and undistributed net income from certain investment funds.
(c)	Net realized gains and change in net unrealized gains on investments
The following represents an analysis of net realized gains and the change in net unrealized gains on investments:
	Three Months Ended
	March 31, 2015			March 31, 2014
Fixed maturities, short-term and other investments
Gross realized gains	$	6,309		$	5,296
Gross realized (losses)	(2,140		)	(1,556		)
Net realized gains on investments	4,169			3,740
Change in net unrealized gains on investments (a)	72,204			55,693
Total net realized and change in net unrealized gains on investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	76,373			59,433
Assets managed on behalf of operating affiliates	—			—
Catastrophe bonds	2,336			797
Noncontrolling interest (a)	(35,079		)	(42,002		)
Total net realized and change in net unrealized gains on investments excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	43,630		$	18,228
(a)	Includes the change in net unrealized gains 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 loss (income) attributable to noncontrolling interest.
(d)	Pledged investments
The following tables outline investments and cash 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, 2015
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			268,907				400,774
$30,000 secured bi-lateral letter of credit facility		30,000			14,747				27,019
Talbot FAL facility		25,000			25,000				31,221
PaCRe senior secured letter of credit facility		10,000			39				—
AlphaCat Re secured letter of credit facility		30,000			30,000				30,097
IPC bi-lateral facility		25,000			12,543				100,549
$230,000 Flagstone bi-lateral facility		230,000			209,070				373,664
Total		$	1,275,000		$	560,306			$	963,324
		December 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			276,455				395,750
$200,000 secured bi-lateral letter of credit facility		200,000			15,649				35,645
Talbot FAL facility		25,000			25,000				31,048
PaCRe senior secured letter of credit facility		10,000			294				—
AlphaCat Re secured letter of credit facility		30,000			30,000				30,078
IPC bi-lateral facility		40,000			15,897				99,437
$375,000 Flagstone bi-lateral facility		375,000			198,389				430,782
Total		$	1,605,000		$	561,684			$	1,022,740
In addition, $3,267,654 of cash and cash equivalents, restricted cash, short-term investments and fixed maturities were pledged during the normal course of business as at March 31, 2015 (December 31, 2014: $3,150,295). Of those, $3,208,722 were held in trust (December 31, 2014: $3,122,074). 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.

Fair_value_measurements

Fair value measurements	3 Months Ended
	Mar. 31, 2015
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 the Company's 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 the Company to change the selection of our valuation technique (for example, from market to cash flow approach) or 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, 2015, 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	$	—		$	771,701		$	—		$	771,701
	Non-U.S. government and government agency	—			243,533			—			243,533
	U.S. states, municipalities and political subdivisions	—			350,843			—			350,843
	Agency residential mortgage-backed securities	—			534,234			—			534,234
	Non-agency residential mortgage-backed securities	—			32,108			—			32,108
	U.S. corporate	—			1,446,146			—			1,446,146
	Non-U.S. corporate	—			510,581			—			510,581
	Bank loans	—			381,621			79,719			461,340
	Catastrophe bonds	—			124,217			3,000			127,217
	Asset-backed securities	—			704,265			—			704,265
	Commercial mortgage-backed securities	—			302,511			—			302,511
	Total fixed maturities	—			5,401,760			82,719			5,484,479
	Total short-term investments (a)	1,084,139			92,389			6,814			1,183,342
	Other investments
	Fund of hedge funds	—			—			1,070			1,070
	Preferred stock	—			3,005			—			3,005
	Hedge funds (b)	—			—			561,318			561,318
	Private equity investments	—			—			52,852			52,852
	Investment funds	—			91,131			162,883			254,014
	Mutual funds	—			9,736			—			9,736
	Total other investments	—			103,872			778,123			881,995
	Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	1,084,139		$	5,598,021		$	867,656		$	7,549,816
	Assets managed on behalf of operating affiliates (a)	(751,473		)	—			—			(751,473		)
	Catastrophe bonds	—			(124,217		)	(3,000		)	(127,217		)
	Noncontrolling interest (b)	—			—			(488,073		)	(488,073		)
	Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	332,666		$	5,473,804		$	376,583		$	6,183,053
	(a)	Included in the short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.
	(b)	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.
	At December 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	$	—		$	760,086		$	—		$	760,086
	Non-U.S. government and government agency	—			278,728			—			278,728
	U.S. states, municipalities and political subdivisions	—			449,623			—			449,623
	Agency residential mortgage-backed securities	—			529,231			—			529,231
	Non-agency residential mortgage-backed securities	—			37,807			—			37,807
	U.S. corporate	—			1,499,706			—			1,499,706
	Non-U.S. corporate	—			563,162			—			563,162
	Bank loans	—			416,256			32,748			449,004
	Catastrophe bonds	—			70,664			5,000			75,664
	Asset-backed securities	—			647,482			—			647,482
	Commercial mortgage-backed securities	—			242,238			—			242,238
	Total fixed maturities	—			5,494,983			37,748			5,532,731
	Total short-term investments (a)	942,716			108,358			—			1,051,074
	Other investments
	Fund of hedge funds	—			—			1,775			1,775
	Preferred stock	—			6,334			—			6,334
	Hedge funds (b)	—			—			496,960			496,960
	Private equity investments	—			—			53,371			53,371
	Investment fund	—			140,045			104,787			244,832
	Mutual funds	—			9,739			—			9,739
	Total other investments	—			156,118			656,893			813,011
	Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	942,716		$	5,759,459		$	694,641		$	7,396,816
Assets managed on behalf of operating affiliates (a)	(696,924		)	—			—			(696,924		)
Catastrophe bonds	—			(70,664		)	(5,000		)	(75,664		)
Noncontrolling interest (b)	—			—			(430,494		)	(430,494		)
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	245,792		$	5,688,795		$	259,147		$	6,193,734
(a)	Included in the short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.
(b)	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.
At March 31, 2015, Level 3 investments excluding the noncontrolling interests totaled $376,583 (December 31, 2014: $259,147), representing 6.1% (December 31, 2014: 4.2%) of total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interests, 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. To the extent that these indications are based on significant unobservable inputs, the relevant bonds will be classified as a Level 3 asset.
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 of 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 majority of 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. To the extent that these valuations are based on significant unobservable inputs, the relevant short term investments will be classified as a Level 3 asset.
Preferred stock
The Company's preferred stock portfolio contains preferred term securities typically sold by non-public financial services companies, through a collateralized debt obligation product and are classified as Level 2 assets. The fair value of these investments is determined based on quoted market prices in active markets.
Investment funds
Investment funds classified as Level 2 assets includes one pooled investment which is invested in fixed income securities with high credit ratings. The investment fund is only open to Lloyd’s 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.
Also included within investment funds is the Company's share of a portfolio of Lloyd's overseas deposits, which is also classified as a Level 2 asset. The underlying deposits are managed centrally by Lloyd's and invested according to local regulatory requirements. The composition of the portfolio varies and the deposits are made across the market. The fair value of the deposits is based on the portfolio level reporting that is provided by Lloyd's.
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, certain bank loans, an investment fund and certain catastrophe bonds are the only financial instruments in this category as at March 31, 2015. 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.
Bank loans
Included in the bank loans portfolio is a collection of loan participations held through an intermediary. These investments are classified as Level 3 assets. A third party pricing service provides monthly valuation reports for each loan and participation using a combination of quotations from loan pricing services, leveraged loan indices or market price quotes obtained directly from the intermediary.
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 which was used as a basis for fair value measurement in the Company's March 31, 2015 Consolidated Balance Sheet. The fund manager has provided an estimate of the fund NAV at March 31, 2015 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 $561,318 at March 31, 2015 (December 31, 2014: $496,960). The hedge funds consist of investments in five Paulson & Co. managed funds (the "Paulson hedge funds") and one hedge fund assumed in the acquisition of Flagstone Reinsurance Holdings, S.A. (the "Flagstone Acquisition") (the "Flagstone hedge fund").
The Paulson hedge funds' administrator provides monthly reported NAVs with a one month delay in its valuation which was used as a partial basis for fair value measurement in the Company's March 31, 2015 Consolidated Balance Sheet. The fund manager provides an estimate of the NAV as at March 31, 2015 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, the Company's valuation estimates have not materially differed from the subsequent NAVs.
The Flagstone hedge fund's administrator provides quarterly NAVs with a three-month delay in valuation which was used as a basis for fair value measurement in the Company's March 31, 2015 Consolidated Balance Sheet.
As these valuation techniques incorporate both observable and significant unobservable inputs, both the Paulson hedge funds and the Flagstone hedge fund are classified as Level 3 assets. The Paulson hedge funds are subject to quarterly liquidity.
Private equity investments
The private equity funds provide quarterly or semi-annual partnership capital statements with a three or six month delay which are used as a basis for valuation in the Company's March 31, 2015 Consolidated Balance Sheet. These private equity investments vary in investment strategies and are not actively traded in any open markets. As this valuation technique can incorporate significant unobservable inputs, the private equity investments are classified as Level 3 assets.
Investment funds
Investment funds classified as Level 3 assets consists of one structured securities fund that invests across asset backed securities, residential mortgage backed securities and commercial mortgage backed securities. The fair value of units in the investment fund is based on the NAV of the fund as reported by the independent fund administrator. The fund's administrator provides a monthly reported NAV with a one-month delay in its valuation which was used as a basis for fair value measurement in the Company's March 31, 2015 Consolidated Balance Sheet. As this valuation technique incorporates both observable and significant unobservable inputs, the investment fund investment is classified as a Level 3 asset.
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, 2015 and 2014:
	Three Months Ended
	31-Mar-15			31-Mar-14
Level 3 investments - Beginning of period	$	694,641		$	576,871
Purchases	145,789			—
Sales	(7,602		)	(3,589		)
Settlements	(3,995		)	—
Net realized (losses) gains	(11		)	10
Change in net unrealized gains	38,834			49,326
Transfers into Level 3	—			6,703
Level 3 investments - End of period	$	867,656		$	629,321
Catastrophe Bonds	(3,000		)	—
Noncontrolling interest (a)	(488,073		)	(531,403		)
Level 3 investments - End of period excluding catastrophe bonds and noncontrolling interest	$	376,583		$	97,918
(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 into or out of Levels 1, 2 and 3 during the three months ended March 31, 2015. 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.

Investments_in_affiliates

Investments in affiliates	3 Months Ended
	Mar. 31, 2015
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, 2015 and December 31, 2014:
		31-Mar-15			31-Dec-14
	Investment affiliates	$	85,982		$	63,506
	Operating affiliates	177,350			197,977
	Investments in affiliates	$	263,332		$	261,483
	(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 "Aquiline II General Partner") pursuant to which the Company has assumed 100% of the Assignor's interest in Aquiline Financial Services Fund II L.P. (the "Aquiline II Partnership") representing a total capital commitment of $50,000 (the "Aquiline II 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 of the Fund dated January 9, 2013 (the "Aquiline II Limited Partnership Agreement").
	On October 2, 2014, the Company assumed an additional investment in the Aquiline II Partnership as part of the Western World acquisition representing a total capital commitment of $10,000. This interest is also governed by the terms of the Aquiline II Limited Partnership Agreement.
	The Partnership provides a quarterly capital account statement, with a three month delay in its valuation, which was used as the basis for calculating the Company's share of partnership income for the period.
	Aquiline Financial Services Fund III L.P.
	On November 7, 2014, the Company, entered into a Subscription Agreement (the "Subscription Agreement") with Aquiline Capital Partners III GP (Offshore) Ltd., a Cayman Islands company limited by shares (the "Aquiline III General Partner") pursuant to which the Company is committing and agreeing to purchase limited partnership or other comparable limited liability equity interests (the "Limited Partnership Interests") in Aquiline Financial Services Fund III L.P., a Cayman Islands exempted limited partnership (the "Aquiline III Partnership"), and/or one or more Alternative Investment Vehicles and Intermediate Entities (together with the Aquiline III Partnership, the "Fund" or the "Entities") with a capital commitment (the "Aquiline III Commitment") in an amount equal to $100,000, as a limited partner in the Aquiline III Partnership. The Limited Partnership Interests are governed by the terms of an Amended and Restated Exempted Limited Partnership Agreement dated as of November 7, 2014 (the “Aquiline III Limited Partnership Agreement”).
	The Partnership provides a quarterly capital account statement, with a three month delay in its valuation, which 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 affiliates balance for the three months ended March 31, 2015 and 2014:
		Three Months Ended
		March 31,			March 31,
		2015			2014
	Investment affiliates, beginning of period	$	63,506		$	34,500
	Capital contributions	19,700			—
	Income from investment affiliate	2,776			5,348
	Investment affiliates, end of period	$	85,982		$	39,848
	The following table presents the Company's investment in the Partnerships as at March 31, 2015:
		Investment in investment affiliate
		Investment at cost			Voting ownership %			Equity Ownership			Carrying Value
	Aquiline Financial Services Fund II L.P.	$	56,563		—	%		8.1	%		$	71,844
	Aquiline Financial Services Fund III L.P.	$	14,138		—	%		13.7	%		$	14,138
	Total	$	70,701								$	85,982
	The following table presents the Company's investment in the Partnership as at December 31, 2014:
		Investment in investment affiliate
		Investment at cost			Voting ownership %			Equity Ownership			Carrying Value
	Aquiline Financial Services Fund II L.P.	$	51,001		—	%		8.1	%		$	63,506
	(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, 2015 and 2014 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, 2015 and 2014 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.
	AlphaCat 2013 is now considered "off-risk" as the risk periods for all risk-linked instruments have expired. As a result, 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, 2015 and 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.
	The risk periods for a majority of the AlphaCat 2014 risk-linked instruments have expired. As a result, partial returns of investment have been made to the investors of AlphaCat 2014. The Company's portion of the returns made during the three months ended March 31, 2015 are included in the table below.
	AlphaCat 2015, Ltd.
	On December 29, 2014, the Company joined with other investors in capitalizing AlphaCat 2015, Ltd. ("AlphaCat 2015"), an entity formed for the purpose of investing in collateralized reinsurance and retrocessional contracts for the January 1, 2015 renewal season. AlphaCat 2015 deploys its capital through transactions entered into by AlphaCat Re and the Company's investment in AlphaCat 2015 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 primarily deploy their capital through the AlphaCat Master Fund Ltd. (the "AlphaCat Master Fund") and AlphaCat Re. All of the funds are variable interest entities, with one being consolidated by the Company as the primary beneficiary and the remaining funds being accounted for as equity method investments because the Company holds an equity interest of less than 50% and has significant influence. One of these funds 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 retained significant influence, this fund was 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 AlphaCat Master Fund and AlphaCat Re, amounted to $113,455 as at January 1, 2014. The deconsolidation resulted in a gain of $1,372 which is included in the Consolidated Statements of Comprehensive Income as other insurance related income for the year ended December 31, 2014. 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 AlphaCat 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. AlphaCat Master Fund and AlphaCat Re are market facing entities which enter into transactions on behalf of AlphaCat 2013, AlphaCat 2014, AlphaCat 2015 and the AlphaCat ILS funds. The Company owns all of the voting equity interest in AlphaCat Master Fund and AlphaCat Re and, as a result, their financial statements are included in the Consolidated Financial Statements of the Company.
	BetaCat ILS funds
	The BetaCat ILS funds invest exclusively in catastrophe bonds (principal-at-risk variable rate notes and other event-linked securities, being referred to collectively as “Cat Bonds”) focused on property and casualty risk issued under Rule 144A of the Securities Act of 1933, following a passive buy-and-hold investment strategy. One of the funds is a variable interest entity and is consolidated by the Company as the primary beneficiary. The remaining fund is consolidated by the Company as it owns all of the voting equity interest. The Company's maximum exposure to either of the funds is the amount of capital invested at any given time. As at March 31, 2015, no third party subscriptions had been received.
	The following tables present a reconciliation of the beginning and ending investment in operating affiliates for the three months ended March 31, 2015 and 2014:
		Three Months Ended March 31, 2015
		AlphaCat Re 2011			AlphaCat Re 2012				AlphaCat 2013				AlphaCat 2014			AlphaCat 2015			AlphaCat ILS funds			Total
	As at December 31, 2014	$	4,606		$	735			$	1,068			$	28,085		$	25,600		$	137,883		$	197,977
	Purchase of shares	—			—				—				—			—			1,070			1,070
	Return of investment	—			—				—				(24,150		)	—			—			(24,150		)
	Income from operating affiliates	(10		)	(25		)		(14		)		(100		)	1,316			1,286			2,453
	As at March 31, 2015	$	4,596		$	710			$	1,054			$	3,835		$	26,916		$	140,239		$	177,350
		Three Months Ended March 31, 2014
		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 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
The following table presents the Company's investments in AlphaCat Re 2011, AlphaCat Re 2012, AlphaCat 2013, AlphaCat 2014, AlphaCat 2015 and the AlphaCat ILS funds in the Consolidated Financial Statements as at March 31, 2015:
	Investment in operating affiliates
	Cost			Voting ownership %			Equity ownership %			Carrying value
AlphaCat Re 2011	$	4,596		43.7	%		22.3	%		$	4,596
AlphaCat Re 2012	710			49	%		37.9	%		710
AlphaCat 2013	1,054			40.9	%		19.7	%		1,054
AlphaCat 2014	3,835			42.3	%		19.6	%		3,835
AlphaCat 2015	25,600			40	%		20	%		26,916
AlphaCat ILS funds	134,161			n/a			(a)			140,239
Total	$	169,956								$	177,350
(a)	Equity ownership in the funds was 7.6%, 25.2% and 9.1%, respectively as at March 31, 2015.
The following table presents the Company's investments in AlphaCat Re 2011, AlphaCat Re 2012, AlphaCat 2013, AlphaCat 2014, AlphaCat 2015 and the AlphaCat ILS funds in the Consolidated Financial Statements as at December 31, 2014:
	Investment in operating affiliates
	Cost			Voting ownership %			Equity ownership %			Carrying value
AlphaCat Re 2011	$	4,606		43.7	%		22.3	%		$	4,606
AlphaCat Re 2012	735			49	%		37.9	%		735
AlphaCat 2013	1,068			40.9	%		19.7	%		1,068
AlphaCat 2014	22,000			42.3	%		19.6	%		28,085
AlphaCat 2015	25,600			40	%		20	%		25,600
AlphaCat ILS funds	133,091			n/a			(a)			137,883
Total	$	187,100								$	197,977
(a)	Equity ownership in the funds was 7.9%, 39.7% and 9.1%, respectively as at December 31, 2014.
(c)	Notes payable and (income) attributable to operating affiliates
Notes are issued during the course of a year by AlphaCat Master Fund and AlphaCat Re to AlphaCat 2014, AlphaCat 2015 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. The underlying capital market products and collateralized reinsurance typically have at least a twelve month duration; however, they do not have a stated maturity date. Since repayment is dependent on the settlement of the underlying transactions, the 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 AlphaCat Master Fund and AlphaCat Re, which are consolidated in the Company’s Consolidated Financial Statements. The effective economic interest in AlphaCat 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. The notes do not have any principal amount, since the final amount payable is dependent on the income or loss. 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.
The following tables present a reconciliation of the beginning and ending notes payable to operating affiliates for the three months ended March 31, 2015 and 2014:
	Three Months Ended March 31, 2015
	AlphaCat 2013			AlphaCat 2014				AlphaCat 2015				AlphaCat ILS funds			Total
As at December 31, 2014	$	—		$	157,384			$	—			$	514,081		$	671,465
Issuance of notes payable to operating affiliates	—			—				137,540				484,324			621,864
Redemption of notes payable to operating affiliates	—			(148,893		)		—				(216,990		)	(365,883		)
Foreign exchange gain	—			(310		)		(246		)		(7,206		)	(7,762		)
As at March 31, 2015	$	—		$	8,181			$	137,294			$	774,209		$	919,684
	Three Months Ended March 31, 2014
	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
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, 2015 amounted to $152,891 and $766,793, respectively (December 31, 2014: $148,264 and $523,201).
The following table presents the (income) attributable to operating affiliate investors for the three months ended March 31, 2015 and 2014:
	Three Months Ended
	March 31,			March 31,
	2015			2014
AlphaCat 2013	$	1		$	(10,476	)
AlphaCat 2014	(156		)	(10,789		)
AlphaCat 2015	(8,773		)	—
AlphaCat ILS funds	(14,278		)	(10,445		)
(Income) attributable to operating affiliate investors	$	(23,206	)	$	(31,710	)
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, 2015 amounted to $3,444 and $19,762, respectively (2014: $6,472 and $25,238).

Noncontrolling_interest

Noncontrolling interest	3 Months Ended
	Mar. 31, 2015
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 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 tables present a reconciliation of the beginning and ending balances of redeemable noncontrolling interest and noncontrolling interest for the three months ended March 31, 2015 and 2014:
		Three Months Ended March 31, 2015
		Redeemable noncontrolling interest			Noncontrolling interest		Total
	As at December 31, 2014	$	79,956		$	458,595	$	538,551
	Issuance of shares	15,700			—		15,700
	Income attributable to noncontrolling interest	3,121			35,856		38,977
	As at March 31, 2015	$	98,777		$	494,451	$	593,228
		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 noncontrolling interest	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

Derivative_instruments

Derivative instruments	3 Months Ended
	Mar. 31, 2015
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, 2015, 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, 2015, 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.
	As at March 31, 2015, the Company held one foreign currency forward contract to mitigate the risk of fluctuations in the U.S. dollar against the Euro that was not designated as a hedging instrument.
	The following table summarizes information on the classification and amount of the fair value of derivatives not designated as hedging instruments on the Consolidated Balance Sheets at March 31, 2015 and December 31, 2014:
			As at March 31, 2015								As at December 31, 2014
	Derivatives not 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		$	22,039		$	—		$	225	$	26,755	$	1,685	$	—
	(a)	Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses respectively on the Consolidated Balance Sheets. The net impact on earnings during the three months ended March 31, 2015, recognized in income within other income, relating to the foreign currency forward contract that was not designated as a hedging instrument was $1 (2014: $nil).
	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, 2015 and December 31, 2014:
			As at March 31, 2015								As at December 31, 2014
	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		$	202,779		$	584		$	9,384	$	189,026	$	401	$	3,136
	Interest rate swap contracts		$	552,263		$	21		$	1,915	$	552,263	$	25	$	1,169
	(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, 2015 and 2014:
			Three Months Ended
	Foreign currency forward contracts		March 31, 2015			March 31, 2014
	Amount of (loss) gain recognized in income on derivative		$	(10,113	)	$	3,303
	Amount of gain (loss) on hedged item recognized in income attributable to risk being hedged		$	10,113		$	(3,303	)
	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, 2015 and 2014:
			Three Months Ended
	Interest rate swap contracts		March 31, 2015			March 31, 2014
	Amount of effective portion recognized in other comprehensive income		$	4,040		$	3,208
	Amount of effective portion subsequently reclassified to earnings		$	(3,239	)	$	(3,208	)
	Amount of ineffective portion excluded from effectiveness testing		$	(801	)	$	—
	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, 2015 or December 31, 2014.
	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, 2015
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, 2015 and 2014:
		Three Months Ended
		March 31,			March 31,
		2015			2014
	Reserve for losses and loss expenses, beginning of period	$	3,234,394		$	3,030,399
	Losses and loss expenses recoverable	(377,466		)	(370,154		)
	Net reserves for losses and loss expenses, beginning of period	2,856,928			2,660,245
	Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
	Current year	324,488			202,086
	Prior years	(83,559		)	(39,415		)
	Total incurred losses and loss expenses	240,929			162,671
	Less net losses and loss expenses paid in respect of losses occurring in:
	Current year	(13,100		)	(7,967		)
	Prior years	(236,003		)	(250,115		)
	Total net paid losses	(249,103		)	(258,082		)
	Foreign exchange (gain) loss	(25,274		)	11,818
	Net reserve for losses and loss expenses, end of period	2,823,480			2,576,652
	Losses and loss expenses recoverable	375,882			348,407
	Reserve for losses and loss expenses, end of period	$	3,199,362		$	2,925,059
	Incurred losses and loss expenses comprise:
		Three Months Ended
		March 31,			March 31,
		2015			2014
	Gross losses and loss expenses	$	264,796		$	181,975
	Reinsurance recoverable	(23,867		)	(19,304		)
	Net incurred losses and loss expenses	$	240,929		$	162,671

Reinsurance

Reinsurance	3 Months Ended
	Mar. 31, 2015
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, 2015, 98.4% (December 31, 2014: 98.0%) of reinsurance recoverables (which includes loss reserves recoverable and recoverables on paid losses and $241,983 of total IBNR recoverable (December 31, 2014: $231,129)) were fully collateralized or from reinsurers rated A- or better.
	Reinsurance recoverables by reinsurer as at March 31, 2015 and December 31, 2014 are as follows:
		March 31, 2015					December 31, 2014
		Reinsurance Recoverable			% of Total		Reinsurance Recoverable		% of Total
	Top 10 reinsurers	$	317,056		78.7	%	$	312,205	75.1	%
	Other reinsurers’ balances > $1 million	79,034			19.6	%	94,247		22.7	%
	Other reinsurers’ balances < $1 million	6,826			1.7	%	9,092		2.2	%
	Total	$	402,916		100	%	$	415,544	100	%
			March 31, 2015
	Top 10 Reinsurers		Rating	Reinsurance Recoverable			% of Total
	Swiss Re		AA-	$	79,535		19.7	%
	Lloyd's Syndicates		A+	61,406			15.2	%
	Everest Re		A+	46,105			11.4	%
	Hannover Re		AA-	41,330			10.3	%
	Fully Collateralized		NR	29,979			7.4	%
	Munich Re		AA-	21,632			5.4	%
	Transatlantic Re		A+	11,605			2.9	%
	XL Re		A+	9,897			2.5	%
	Merrimack Mutual Fire Insurance		A+	8,076			2	%
	Hamilton Re		A-	7,491			1.9	%
	Total			$	317,056		78.7	%
	NR: Not rated
			December 31, 2014
	Top 10 Reinsurers		Rating	Reinsurance Recoverable			% of Total
	Swiss Re		AA-	$	70,848		17	%
	Lloyd's Syndicates		A+	62,318			15	%
	Everest Re		A+	51,425			12.4	%
	Hannover Re		AA-	40,927			9.8	%
	Fully Collateralized		NR	23,315			5.6	%
	Munich Re		AA-	19,384			4.7	%
	Transatlantic Re		A+	12,418			3	%
	XL Re		A+	11,114			2.7	%
	Berkshire Hathaway Homestate		AA+	10,372			2.5	%
	Merrimack Mutual Fire Insurance		A+	10,084			2.4	%
	Total			$	312,205		75.1	%
	NR: Not rated
	At March 31, 2015 and December 31, 2014, the provision for uncollectible reinsurance relating to reinsurance recoverables was $4,834 and $4,755, 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, 2015
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 3, 2015, the Board of Directors of the Company approved an increase in the Company's common share purchase authorization to $750,000. This amount is in addition to the $2,274,401 of common shares repurchased by the Company through February 3, 2015 under its previously authorized share repurchase programs.
	The Company has repurchased 71,475,993 common shares for an aggregate purchase price of $2,289,409 from the inception of its share repurchase program to March 31, 2015. The Company had $734,992 remaining under its authorized share repurchase program as of March 31, 2015.
	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, 2014	155,554,224
	Restricted share awards vested, net of shares withheld	14,447
	Restricted share units vested, net of shares withheld	1,997
	Options exercised	704,974
	Warrants exercised	473,817
	Direct issuance of common stock	324
	Common shares issued, March 31, 2015	156,749,783
	Treasury shares, March 31, 2015	(73,114,868	)
	Common shares outstanding, March 31, 2015	83,634,915
		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
	(b)	Warrants
	During the three months ended March 31, 2015, 798,575 warrants were exercised, which resulted in the issuance of 473,817 common shares. During the three months ended March 31, 2014, 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, 2015 were 4,375,538 (December 31, 2014: 5,174,114). No further warrants are anticipated to be issued.
	(c)	Dividends
	On February 3, 2015, the Company announced a quarterly cash dividend of $0.32 (2014: $0.30) per common share and $0.32 per common share equivalent for which each outstanding warrant is exercisable. This dividend was paid on March 31, 2015 to holders of record on March 13, 2015.

Stock_plans

Stock plans	3 Months Ended
	Mar. 31, 2015
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 905,848 shares remain available for issuance at March 31, 2015. 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 recognized for the three months ended March 31, 2015 and 2014.
	Activity with respect to options for the three months ended March 31, 2015 was as follows:
		Options		Weighted Average Grant Date Fair Value				Weighted Average Grant Date Exercise Price
	Options outstanding, December 31, 2014	1,160,057		$	7.12			$	17.74
	Options exercised	(1,017,165	)	7.36				16.55
	Options outstanding, March 31, 2015	142,892		$	5.45			$	26.24
	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
	At March 31, 2015 and December 31, 2014, 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 $8,479 were recorded for the three months ended March 31, 2015 (2014: $7,001). 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, 2015 was as follows:
		Restricted Share Awards		Weighted Average Grant Date Fair Value
	Restricted share awards outstanding, December 31, 2014	2,858,711		$	35.81
	Restricted share awards vested	(19,682	)	32.25
	Restricted share awards forfeited	(2,410	)	41.5
	Restricted share awards outstanding, March 31, 2015	2,836,619		$	35.83
	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
	At March 31, 2015, there were $66,382 (December 31, 2014: $74,670) of total unrecognized share compensation expenses in respect of restricted share awards that are expected to be recognized over a weighted-average period of 2.6 years (December 31, 2014: 2.7 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 $262 were recorded for the three months ended March 31, 2015 (2014: $166). 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, 2015 was as follows:
		Restricted Share Units		Weighted Average Grant Date Fair Value
	Restricted share units outstanding, December 31, 2014	103,484		$	36.54
	Restricted share units vested	(1,997	)	38.24
	Restricted share units issued in lieu of cash dividends	747		36.54
	Restricted share units forfeited	(893	)	35.42
	Restricted share units outstanding, March 31, 2015	101,341		$	36.51
	Activity with respect to unvested restricted share units for the three months ended March 31, 2014 was as follows:
		Restricted		Weighted Average Grant Date Fair Value
		Share Units
	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
	At March 31, 2015, there were $2,493 (December 31, 2014: $2,774) of total unrecognized share compensation expenses in respect of restricted share units that are expected to be recognized over a weighted-average period of 2.9 years (December 31, 2014: 3.1 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 $313 were recorded for the three months ended March 31, 2015 (2014: $(20)). 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, 2015 was as follows:
		Performance Share Awards		Weighted Average Grant Date Fair Value
	Performance share awards outstanding, December 31, 2014	106,369		$	36.03
	Performance share awards outstanding, March 31, 2015	106,369		$	36.03
	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
	At March 31, 2015, there were $1,937 (December 31, 2014: $2,232) 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, 2014: 2.1 years).
(b)	Total share compensation expenses
The breakdown of share compensation expenses by award type for the periods indicated was as follows:
	Three Months Ended
	March 31,			March 31,
	2015			2014
Restricted share awards	$	8,479		$	7,001
Restricted share units	262			166
Performance share awards	313			(20		)
Total	$	9,054		$	7,147

Debt_and_financing_arrangement

Debt and financing arrangements	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Debt and financing arrangements	Debt and financing arrangements
	(a)	Financing structure
	The financing structure at March 31, 2015 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	134,011			134,011				134,011
	Flagstone 2007 Junior Subordinated Deferrable Debentures	113,750			113,750				113,750
	Total debentures payable	597,761			537,561				537,561
	2010 Senior Notes due 2040	250,000			250,000				247,333
	Total debentures and senior notes payable	847,761			787,561				784,894
	$400,000 syndicated unsecured letter of credit facility	400,000			—				—
	$525,000 syndicated secured letter of credit facility	525,000			268,907				—
	$30,000 secured bi-lateral letter of credit facility	30,000			14,747				—
	Talbot FAL facility	25,000			25,000				—
	PaCRe senior secured letter of credit facility	10,000			39				—
	AlphaCat Re secured letter of credit facility	30,000			30,000				—
	IPC bi-lateral facility	25,000			12,543				—
	$230,000 Flagstone bi-lateral facility	230,000			209,070				—
	Total credit and other facilities	1,275,000			560,306				—
	Total debt and financing arrangements	$	2,122,761		$	1,347,867			$	784,894
	The financing structure at December 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	135,727			135,727				135,727
	Flagstone 2007 Junior Subordinated Deferrable Debentures	113,750			113,750				113,750
	Total debentures payable	599,477			539,277				539,277
	2010 Senior Notes due 2040	250,000			250,000				247,306
	Total debentures and senior notes payable	849,477			789,277				786,583
	$400,000 syndicated unsecured letter of credit facility	400,000			—				—
	$525,000 syndicated secured letter of credit facility	525,000			276,455				—
	$200,000 secured bi-lateral letter of credit facility	200,000			15,649				—
	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			30,000				—
	IPC bi-lateral facility	40,000			15,897				—
	$375,000 Flagstone bi-lateral facility	375,000			198,389				—
	Total credit and other facilities	1,605,000			561,684				—
	Total debt and financing arrangements	$	2,454,477		$	1,350,961			$	786,583
	(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	%	(a)	Quarterly
	Flagstone 2006 Junior Subordinated Deferrable Debentures	August 23, 2006	$	134,011	September 15, 2036	3.54	%	(b)	Quarterly
	2007 Junior Subordinated Deferrable Debentures	June 21, 2007	$	200,000	June 15, 2037	8.48	%	(a)	Quarterly
	Flagstone 2007 Junior Subordinated Deferrable Debentures	June 8, 2007	$	88,750	July 30, 2037	3	%	(b)	Quarterly
	Flagstone 2007 Junior Subordinated Deferrable Debentures	September 20, 2007	$	25,000	September 15, 2037	3.1	%	(b)	Quarterly
	2010 Senior Notes due 2040	January 26, 2010	$	250,000	January 26, 2040	8.875	%	(a)	Semi-annually in arrears
	(a)	Fixed interest rate.
	(b)	Variable interest rate is the three-month LIBOR, reset quarterly, plus spread as noted in the table.
	The following table summarizes the key terms of the Company's senior notes and junior subordinated deferrable debentures as at March 31, 2015:
	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	$	134,011	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 the Company's 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, 2015 and 2014.
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 2020.
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, 2015 and 2014.
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, 2015 and 2014.
Future payments of principal of $537,561 on the debentures discussed above are all expected to be after 2020.
(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 various counter parties 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, 2015, there were $268,907 in outstanding letters of credit under the Four Year Secured Facility (December 31, 2014: $276,455) and $nil (December 31, 2014: $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, 2015, and throughout the reporting periods presented, the Company was in compliance with all covenants and restrictions under the Credit Facilities.
ii.	$25,000 Talbot FAL facility
On November 19, 2013, Validus Holdings, Ltd. (“Validus Holdings”), as Guarantor, and its wholly-owned subsidiary, Talbot Holdings Ltd. (“Talbot Holdings”), as Borrower, entered into an Amendment and Restatement Agreement relating to its $25,000 Funds-at-Lloyd’s Standby Letter of Credit Facility (the “Facility”) which amends the Facility to support underwriting capacity provided to Talbot 2002 Underwriting Ltd through Syndicate 1183 at Lloyd’s of London for the 2015 and prior underwriting years of account (the “Restated Facility”). The Restated Facility was provided and arranged by Lloyds Bank plc and ING Bank N.V., London Branch. The Restated Facility provides for the issuance of up to $25,000 (denominated in US Dollars or Pound Sterling) of secured letters of credit to be issued for the benefit of Lloyd’s of London. The existing $25,000 secured letter of credit will be extended to provide for an extended termination date covering the 2015, 2016 and prior underwriting years of account under the Restated Facility.
The Restated Facility contains affirmative covenants that include, among other things, (i) the requirement that Validus Holdings and its subsidiaries initially maintain a minimum level of consolidated net worth of at least $3,225,727, and commencing with the fiscal quarter ending September 30, 2013, to be increased quarterly by an amount equal to 50% of our consolidated net income (if positive) for such quarter plus 50% of the aggregate increases in our consolidated shareholder’s equity interests by reason of issuance and sale of Validus Holdings’ common equity interests including upon any conversion of Validus Holdings’ debt securities into equity interests during such quarter and (ii) the requirement that Validus Holdings and its subsidiaries maintain at all times a consolidated total debt to consolidated total capitalization ratio not greater than 0.35:1.00. The Restated Facility defines net worth to include preferred and preference securities and “hybrid” securities (which includes Validus Holdings’ and its Flagstone subsidiaries’ Junior Subordinated Deferrable Debentures). The Restated Facility also requires that Talbot Holdings maintain at least $300,000 of its own Funds at Lloyd’s, and to obtain a letter of comfort from Lloyd’s of London confirming that Lloyd’s of London will take into account a requested order of drawdown to drawdown Talbot Holdings’ own Funds at Lloyd’s ahead of letters of credit issued under the Facility.
The Restated Facility also contains restrictions on Validus Holdings’ ability to pay dividends and other payments in respect of equity interests at any time that it is otherwise in default under the Facility (with certain exceptions for dividends in respect of preferred securities and hybrid securities, which are only limited during the continuance of certain specified defaults), incur debt at its subsidiaries level, transact with affiliates, incur liens, sell assets and merge or consolidate with others and other restrictions customary for transactions of this type, in each case subject to agreed exceptions.
Secured letter of credit availability under the Restated Facility is subject to a borrowing base limitation comprised of (a) the aggregate amount of cash and eligible securities owned by Validus Reinsurance, Ltd. and placed in a collateral account subject to a customary account control agreement in favor of the lenders and agents under the Restated Facility multiplied by (b) an agreed upon advance rate applicable for each category of cash and eligible securities. Obligations in respect of secured letters of credit under the Restated Facility are secured by a first-priority security interest on the cash and eligible securities comprising the borrowing base in favor of the trustee under the Restated Facility.
The Restated Facility contains representations and warranties customary for facilities of this type. The Restated Facility also contains customary events of default including without limitation, with agreed grace periods and thresholds, failure to make payments due under the Restated Facility, material inaccuracy of representations and warranties, breach of covenants, cross defaults to material indebtedness, bankruptcy defaults, judgments defaults, and failure to maintain certain material insurance licenses.
As of March 31, 2015, the Company had $25,000 (December 31, 2014: $25,000) in outstanding letters of credit under the Talbot FAL facility.
As of March 31, 2015, and throughout the reporting periods presented, the Company was in compliance with all covenants and restrictions under the Talbot FAL facility.
iii.	$25,000 IPC bi-lateral facility
The Company assumed an existing evergreen letter of credit facility through the acquisition of IPC Holdings, Ltd. (the "IPC bi-lateral facility"). As of March 31, 2015, there were $12,543 outstanding letters of credit issued under the IPC bi-lateral facility (December 31, 2014: $15,897). As of March 31, 2015, and throughout the reporting periods presented, the Company was in compliance with all covenants and restrictions under the IPC bi-lateral facility.
iv.	$30,000 secured bi-lateral letter of credit facility
The Company is party to an evergreen secured bi-lateral letter of credit facility with Citibank Europe plc (the “Secured bi-lateral letter of credit facility”). As of March 31, 2015, $14,747 (December 31, 2014: $15,649) 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, 2015, and throughout the reporting periods presented, the Company is in compliance with all terms and covenants thereof. During the period ended March 31, 2015 the size of the facility was decreased to $30,000 from $200,000.
v.	$10,000 PaCRe senior secured letter of credit facility
On May 11, 2012, PaCRe and its subsidiary, PaCRe Investments, Ltd. entered into a secured evergreen credit and letter of credit facility with JPMorgan Chase Bank, N.A. This facility provides for revolving borrowings by PaCRe and for letters of credit issued by PaCRe to be used to support its reinsurance obligations in aggregate amount of $10,000. As of March 31, 2015, $39 (December 31, 2014: $294) of letters of credit were outstanding under this facility. As of March 31, 2015, 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
In 2013, AlphaCat Re entered into a secured evergreen letter of credit facility with Comerica Bank. This facility provided for letters of credit issued by AlphaCat Re 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, 2015, $30,000 (December 31, 2014: $30,000) of letters of credit were outstanding under this facility. As of March 31, 2015, and throughout the reporting periods presented, AlphaCat Re was in compliance with all covenants and restrictions thereof.
vii.	$230,000 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, 2015, the Flagstone Bi-Lateral Facility had $209,070 (December 31, 2014: $198,389) letters of credit issued and outstanding. As of March 31, 2015, and throughout the reporting periods presented, the Company was in compliance with all covenants and restrictions under the Flagstone Bi-Lateral Facility. During the period ended March 31, 2015 the size of the facility was decreased to $230,000 from $375,000.
(d)	Finance expenses
Finance expenses consist of interest on the junior subordinated deferrable debentures and senior notes, the amortization of debt offering costs, credit facilities fees, bank charges, AlphaCat financing fees and Talbot FAL costs as follows:
	Three Months Ended
	March 31,			March 31,
	2015			2014
2006 Junior Subordinated Deferrable Debentures	$	2,187		$	2,187
2007 Junior Subordinated Deferrable Debentures	1,809			1,809
Flagstone 2006 Junior Subordinated Deferrable Debentures	2,218			2,223
Flagstone 2007 Junior Subordinated Deferrable Debentures	1,758			1,750
2010 Senior Notes due 2040	5,597			5,597
Credit facilities	1,707			1,559
Bank charges	98			113
AlphaCat ILS funds fees (a)	4,428			677
Talbot FAL Facility	50			(15		)
Total finance expenses	$	19,852		$	15,900
(a)	Includes finance expenses incurred by AlphaCat Managers, Ltd. in relation to fund raising for the AlphaCat ILS funds, AlphaCat 2015, AlphaCat 2014 and AlphaCat 2013.

Accumulated_other_comprehensiv

Accumulated other comprehensive loss	3 Months Ended
	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive loss	Accumulated other comprehensive loss
	The changes in accumulated other comprehensive loss, by component for the three months ended March 31, 2015 and 2014 is as follows:
	Three Months Ended March 31, 2015	Foreign currency items			Decrease in minimum pension liability			Losses on cash flow hedge			Total
	Balance beginning of period, net of tax	$	(8,118	)	$	(210	)	$	(228	)	$	(8,556	)
	Net current period other comprehensive income, net of tax	(3,019		)	(265		)	(801		)	(4,085		)
	Balance end of period, net of tax	$	(11,137	)	$	(475	)	$	(1,029	)	$	(12,641	)
	Three Months Ended March 31, 2014	Foreign currency items			Total
	Balance beginning of period, net of tax	$	(617	)	$	(617	)
	Net current period other comprehensive income, net of tax	462			462
	Balance end of period, net of tax	$	(155	)	$	(155	)

Commitments_and_contingencies

Commitments and contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Commitments and contingencies
	(a)	Concentrations of credit risk
	The Company attempts to limit its credit exposure by purchasing high quality fixed income investments to maintain a minimum weighted-average portfolio credit rating of A+. In addition, the portfolio limits the amount of “risk assets,” such as non-investment grade debt and equity securities, to a maximum of 35% of shareholders’ equity. The Company also limits its exposure to any single issuer to 3.5% of its investment portfolio or less, excluding government and agency securities, depending on the credit rating of the issuer. With the exception of the Company's bank loan portfolio, which represents 6.1% of the Company's total investments as at March 31, 2015, and certain capital securities issued by investment grade corporations, the minimum credit rating of any security purchased is Baa3/BBB-. In total, investments in below investment grade securities are limited to no more than 10% of the Company's investment portfolio. As at March 31, 2015, 9.2% of the Company's total investment portfolio was below investment grade. 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, 2015.
	(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:
		2015 Underwriting Year		2014 Underwriting Year
	Talbot FAL facility	$	25,000	$	25,000
	Group funds	570,100		450,000
	Total	$	595,100	$	475,000
	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 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 2015 estimated premium income at Lloyd's of £625,000, at the March 31, 2015 exchange rate of £1 equals $1.4861 and assuming the maximum 3% assessment, the Company would be assessed approximately $27,864.
	(d)	Investment in affiliate commitments
	As discussed in Note 5 "Investments in affiliates," on December 20, 2011 the Company entered into an Assignment and Assumption Agreement with Aquiline Capital Partners LLC, pursuant to which it assumed total capital commitments of $50,000. This interest is governed by the terms of an Amended and Restated Exempted Limited Partnership Agreement dated as of January 9, 2013. The Company’s remaining commitment at March 31, 2015 was $2,865 (December 31, 2014: $7,500).
	On October 2, 2014, the Company assumed an additional investment in Aquiline Capital Partners II GP (Offshore) Ltd. as part of the Western World acquisition representing a total capital commitment of $10,000. This interest is governed by the terms of an Amended and Restated Exempted Limited Partnership Agreement dated as of January 9, 2013. The Company's remaining capital commitment at March 31, 2015 was $572 (December 31, 2014: $1,499).
	On November 7, 2014 the Company entered into a Subscription Agreement with Aquiline Capital Partners III GP (Offshore) Ltd., pursuant to which it assumed total capital commitments of $100,000 in respect of Limited Partnership Interests in Aquiline Financial Services Fund III L.P. (the "Fund"). The Limited Partnership Interests are governed by the terms of the Aquiline III Limited Partnership Agreement dated November 7, 2014. The Company’s remaining commitment at March 31, 2015 was $85,862 (December 31, 2014: $100,000).
	On December 29, 2014, the Company entered into an agreement with AlphaCat 2015 pursuant to which it assumed total capital commitments of $28,000. The Company’s remaining commitment at March 31, 2015 was $2,400 (December 31, 2014: $2,400).
	On December 29, 2014, the Company entered into an agreement with an AlphaCat ILS fund pursuant to which it assumed total capital commitments of $20,000. The Company’s remaining commitment at March 31, 2015 was $6,930 (December 31, 2014: $8,000).
	(e)	Fixed maturity commitment
	As at March 31, 2015, the Company had an outstanding commitment to participate in certain revolver loan facilities through participation agreements with an established loan originator. The undrawn amount under the revolver facility participations as at March 31, 2015 was $16,343 (December 31, 2014: $7,539).
	(f)	Other investment commitments
	At March 31, 2015, the Company had capital commitments in other investments of $153,000 (December 31, 2014: $153,000). The Company's remaining commitment to these investments at March 31, 2015 was $81,157 (December 31, 2014: $83,712).
	(g)	Multi-Beneficiary Reinsurance Trust ("MBRT")
	In December 2014, the Company established an MBRT to collateralize its (re)insurance liabilities associated with and for the benefit of U.S. domiciled cedants, and was approved as a trusteed reinsurer in the State of New Jersey. As a result, cedants domiciled in that state will receive automatic credit in their regulatory filings for reinsurance provided prospectively by the Company.

Related_party_transactions

Related party transactions	3 Months Ended
	Mar. 31, 2015
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 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, 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, 2015 of $1,870 (2014: $1,373) with $1,433 included in premiums receivable at March 31, 2015 (December 31, 2014: $335). The Company also recognized reinsurance premiums ceded during the three months ended March 31, 2015 of $29 (2014: $5) and had reinsurance balances payable of $4 at March 31, 2015 (December 31, 2014: $4). The Company recorded $1,067 of loss reserves recoverable at March 31, 2015 (December 31, 2014: $1,063). Earned premium adjustments of $783 were recorded during the three months ended March 31, 2015 (2014: $1,441).
	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, 2015 were $285 (2014: $56), with $313 included in accounts payable and accrued expenses at March 31, 2015 (December 31, 2014: $515).
	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 "Aquiline II Partnership") representing a total capital commitment of $50,000 (the "Aquiline II Commitment"), as a limited partner in the Partnership (the "Transferred Interest"). On October 2, 2014, the Company assumed an additional investment in the Aquiline II Partnership as part of the Western World acquisition representing a total capital commitment of $10,000. 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, 2015, the Company incurred $448 (2014: $nil) in partnership fees and made capital contributions of $5,562 (2014: $nil), with $nil included in accounts payable and accrued expenses at March 31, 2015 (December 31, 2014: $nil).
	On November 7, 2014, the Company, entered into a Subscription Agreement (the "Subscription Agreement") with Aquiline Capital Partners III GP (Offshore) Ltd., a Cayman Islands company limited by shares (the "Aquiline III General Partner") pursuant to which the Company is committing and agreeing to purchase limited partnership or other comparable limited liability equity interests (the "Limited Partnership Interests") in Aquiline Financial Services Fund III L.P., a Cayman Islands exempted limited partnership (the "Aquiline III Partnership"), and/or one or more Alternative Investment Vehicles and Intermediate Entities (together with the Aquiline III Partnership, the "Fund" or the "Entities") with a capital commitment (the "Aquiline III Commitment") in an amount equal to $100,000, as a limited partner in the Aquiline Financial Services III Partnership. For the three months ended March 31, 2015, the Company incurred $nil (2014: $nil) partnership fees and made capital contributions of $14,138 (2014: $nil), with $nil included in accounts payable and accrued expenses at March 31, 2015 (December 31, 2014: $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 arm's length consideration.

Earnings_per_share

Earnings per share	3 Months Ended
	Mar. 31, 2015
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, 2015 and 2014:
		Three Months Ended
		March 31,			March 31,
		2015			2014
	Basic earnings per share
	Net income	$	212,388		$	205,897
	Income attributable to noncontrolling interest	(38,977		)	(43,509		)
	Net income available to Validus	173,411			162,388
	Less: Dividends and distributions declared on outstanding warrants	(1,405		)	(1,552		)
	Income available to common shareholders	$	172,006		$	160,836
	Weighted average number of common shares outstanding	83,251,243			93,451,999
	Basic earnings per share available to common shareholders	$	2.07		$	1.72
	Earnings per diluted share
	Net income	$	212,388		$	205,897
	Income attributable to noncontrolling interest	(38,977		)	(43,509		)
	Net income available to Validus	173,411			162,388
	Less: Dividends and distributions declared on outstanding warrants	—			—
	Income available to common shareholders	$	173,411		$	162,388
	Weighted average number of common shares outstanding	83,251,243			93,451,999
	Share equivalents:
	Warrants	2,745,066			2,716,010
	Stock options	473,424			750,369
	Unvested restricted shares	1,113,396			881,141
	Weighted average number of diluted common shares outstanding	87,583,129			97,799,519
	Earnings per diluted share available to common shareholders	$	1.98		$	1.66
	Share equivalents that would result in the issuance of 645 common shares (2014: 12,498) were outstanding for the three months ended March 31, 2015, 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, 2015
Segment Reporting [Abstract]
Segment information	Segment information
	The Company conducts its operations worldwide through four operating segments, which have been determined under U.S. GAAP segment reporting to be Validus Re, AlphaCat, Talbot and Western World. 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, AlphaCat 2014 and AlphaCat 2015, as well as PaCRe, the AlphaCat ILS funds and the BetaCat ILS funds.
	Talbot Segment
	The Talbot segment focuses on a wide range of marine and energy, war, political violence, commercial property, financial lines, contingency, 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.
	Western World Segment
	The Western World segment is focused on providing commercial insurance products on a surplus lines and specialty admitted basis. Western World specializes in underwriting classes of business that are not easily placed in the standard insurance market due to their complexity, high hazard, or unusual nature; including general liability, property and professional liability classes of business.
	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, 2015		Validus Re Segment				AlphaCat Segment				Talbot Segment				Western World Segment				Corporate & Eliminations				Total
	Underwriting income
	Gross premiums written		$	711,212			$	102,564			$	270,077			$	56,947			$	(21,302	)		$	1,119,498
	Reinsurance premiums ceded		(113,296		)		(4,538		)		(91,075		)		(3,233		)		21,302				(190,840		)
	Net premiums written		597,916				98,026				179,002				53,714				—				928,658
	Change in unearned premiums		(344,828		)		(63,831		)		43,587				14,168				—				(350,904		)
	Net premiums earned		253,088				34,195				222,589				67,882				—				577,754
	Underwriting deductions
	Losses and loss expenses		113,128				(844		)		78,128				50,517				—				240,929
	Policy acquisition costs		42,094				3,660				49,104				4,279				(501		)		98,636
	General and administrative expenses		19,509				4,002				36,494				10,627				14,396				85,028
	Share compensation expenses		2,578				149				2,957				477				2,893				9,054
	Total underwriting deductions		177,309				6,967				166,683				65,900				16,788				433,647
	Underwriting income (loss)		$	75,779			$	27,228			$	55,906			$	1,982			$	(16,788	)		$	144,107
	Net investment income		18,776				1,585				6,305				5,303				(948		)		31,021
	Other insurance related income (loss)		315				5,771				54				263				(1,571		)		4,832
	Finance expenses		(3,871		)		(4,516		)		(87		)		—				(11,378		)		(19,852		)
	Operating income (loss) before taxes, income from operating affiliates and (income) attributable to operating affiliate investors		90,999				30,068				62,178				7,548				(30,685		)		160,108
	Tax benefit (expense)		1,880				—				(883		)		(3,723		)		161				(2,565		)
	Income from operating affiliates		—				2,453				—				—				—				2,453
	(Income) attributable to operating affiliate investors		—				(23,206		)		—				—				—				(23,206		)
	Net operating income (loss)		$	92,879			$	9,315			$	61,295			$	3,825			$	(30,524	)		$	136,790
	Net realized gains (losses) on investments		1,809				(11		)		871				1,500				—				4,169
	Change in net unrealized gains (losses) on investments		20,578				37,535				7,911				7,138				(958		)		72,204
	Income from investment affiliate		1,933				—				—				843				—				2,776
	Foreign exchange (losses) gains		(5,024		)		(95		)		(485		)		—				2,053				(3,551		)
	Net income (loss)		$	112,175			$	46,744			$	69,592			$	13,306			$	(29,429	)		$	212,388
	Net (income) attributable to noncontrolling interest		—				(38,977		)		—				—				—				(38,977		)
	Net income (loss) available (attributable) to Validus		$	112,175			$	7,767			$	69,592			$	13,306			$	(29,429	)		$	173,411
	Selected ratios (a):
	Net premiums written / Gross premiums written		84.1		%		95.6		%		66.3		%		94.3		%						83		%
	Losses and loss expenses		44.7		%		(2.5		)%		35.1		%		74.4		%						41.7		%
	Policy acquisition costs		16.7		%		10.7		%		22.1		%		6.3		%						17.1		%
	General and administrative expenses (b)		8.7		%		12.1		%		17.7		%		16.4		%						16.3		%
	Expense ratio		25.4		%		22.8		%		39.8		%		22.7		%						33.4		%
	Combined ratio		70.1		%		20.3		%		74.9		%		97.1		%						75.1		%
	Total assets		$	4,567,449			$	1,954,260			$	2,933,104			$	1,512,848			$	86,789			$	11,054,450
	(a)	Ratios are based on net premiums earned.
	(b)	The general and administrative expenses ratio includes share compensation expenses.
	Three Months Ended March 31, 2014		Validus Re Segment (c)				AlphaCat Segment				Talbot Segment				Corporate & Eliminations (c)				Total
	Underwriting income
	Gross premiums written		$	666,163			$	84,347			$	290,695			$	(29,214	)		$	1,011,991
	Reinsurance premiums ceded		(129,817		)		(3,700		)		(90,605		)		29,214				(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 insurance related income (loss)		977				9,497				17				(2,454		)		8,037
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		126,486				41,139				33,530				(32,611		)		168,544
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)		$	127,064			$	14,356			$	33,660			$	(33,279	)		$	141,801
Net realized (losses) gains on investments		2,446				1,225				69				—				3,740
Change in net unrealized losses on investments		11,898				45,872				2,577				(4,654		)		55,693
Income from investment affiliate		5,348				—				—				—				5,348
Foreign exchange gains (losses)		(6,176		)		38				(150		)		(190		)		(6,478		)
Other income		5,793				—				—				—				5,793
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		80.5		%		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		$	5,730,615			$	1,582,014			$	2,975,533			$	94,788			$	10,382,950
(a)	Ratios are based on net premiums earned.
(b)	The general and administrative expense ratio includes share compensation expenses.
(c)	During the first quarter of 2015, certain intercompany reinsurance transactions were presented on a net basis for segmental reporting purposes. As a result, gross premiums written and reinsurance premiums ceded for the Validus Re segment and Corporate & Eliminations were reduced by $12,823 for the three months ended March 31, 2014 for comparative purposes. There was no impact to total gross premiums written and reinsurance premiums ceded on a consolidated basis.
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, 2015
	Gross Premiums Written
	Validus Re				AlphaCat				Talbot				Western World				Eliminations				Total				%
United States	$	338,819			$	13,575			$	28,058			$	56,947			$	(1,494	)		$	435,905			38.9	%
Worldwide excluding	34,994				5,833				34,942				—				(1,029		)		74,740				6.7	%
United States (a)
Australia and New Zealand	9,868				—				1,876				—				(155		)		11,589				1	%
Europe	24,506				1,768				13,214				—				(844		)		38,644				3.5	%
Latin America and Caribbean	8,878				—				22,692				—				(3,524		)		28,046				2.5	%
Japan	1,384				—				754				—				(13		)		2,125				0.2	%
Canada	2,187				194				1,698				—				(78		)		4,001				0.4	%
Rest of the world (b)	18,726				—				23,006				—				(2,319		)		39,413				3.5	%
Sub-total, non United States	100,543				7,795				98,182				—				(7,962		)		198,558				17.8	%
Worldwide including	85,056				77,894				21,794				—				(11,854		)		172,890				15.4	%
United States (a)
Other location non-specific (c)	186,794				3,300				122,043				—				8				312,145				27.9	%
Total	$	711,212			$	102,564			$	270,077			$	56,947			$	(21,302	)		$	1,119,498			100	%
	Three Months Ended March 31, 2014
	Gross Premiums Written
	Validus Re (d)				AlphaCat				Talbot				Eliminations (d)				Total				%
United States	$	243,032			$	8,698			$	26,311			$	(2,320	)		$	275,721			27.3	%
Worldwide excluding	58,523				7,678				37,182				(1,027		)		102,356				10	%
United States (a)
Australia and New Zealand	12,860				1,019				2,880				(326		)		16,433				1.6	%
Europe	35,878				1,301				18,791				(1,767		)		54,203				5.4	%
Latin America and Caribbean	14,337				—				31,239				(10,669		)		34,907				3.4	%
Japan	167				—				538				(61		)		644				0.1	%
Canada	2,547				216				3,145				(172		)		5,736				0.6	%
Rest of the world (b)	18,795				—				18,404				(2,387		)		34,812				3.4	%
Sub-total, non United States	143,107				10,214				112,179				(16,409		)		249,091				24.5	%
Worldwide including	102,284				65,435				23,653				(11,418		)		179,954				17.8	%
United States (a)
Other location non-specific (c)	177,740				—				128,552				933				307,225				30.4	%
Total	$	666,163			$	84,347			$	290,695			$	(29,214	)		$	1,011,991			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.
(d)	During the first quarter of 2015, certain intercompany reinsurance transactions were presented on a net basis for segmental reporting purposes. As a result, gross premiums written for the Validus Re segment and Corporate & Eliminations were reduced by $12,823 for the three months ended March 31, 2014 for comparative purposes. There was no impact to total gross premiums written on a consolidated basis.

Condensed_consolidating_financ

Condensed consolidating financial information	3 Months Ended
	Mar. 31, 2015
Condensed Consolidating Financial Information [Abstract]
Condensed consolidating financial information	Condensed consolidating financial information
	The following tables present condensed consolidating balance sheets as at March 31, 2015 and December 31, 2014, condensed consolidating statements of comprehensive income and condensed consolidating statements of cash flows for the three months ended March 31, 2015 and 2014, respectively, for Validus Holdings, Ltd. (the “Parent Guarantor”), Validus Holdings (UK) plc (the “Subsidiary Issuer”) and the non-guarantor subsidiaries of Validus Holdings, Ltd. The Subsidiary Issuer is a wholly-owned subsidiary of the Parent Guarantor. Investments in subsidiaries are accounted for under the equity method for purposes of the supplemental consolidating presentation and earnings of subsidiaries are reflected in the investment accounts and earnings. The Subsidiary Issuer is only allowed to issue senior notes that are fully and unconditionally guaranteed by the Parent Guarantor.
	Condensed Consolidating Balance Sheet	Validus Holdings, Ltd.			Validus Holdings			Other			Consolidating Adjustments (b)			Validus Holdings, Ltd.
	As at March 31, 2015	(Parent Guarantor)			(UK) plc			Validus Holdings, Ltd.						Consolidated
					(Subsidiary Issuer)			Subsidiaries
								(Non-guarantor Subsidiaries) (a)
	Assets
	Fixed maturities, at fair value	$	28,817		$	—		$	5,515,862		$	(60,200	)	$	5,484,479
	Short-term investments, at fair value	—			—			1,183,342			—			1,183,342
	Other investments, at fair value	—			—			950,992			(68,997		)	881,995
	Cash and cash equivalents	24,148			20			446,961			—			471,129
	Restricted cash	—			—			186,423			—			186,423
	Total investments and cash	52,965			20			8,283,580			(129,197		)	8,207,368
	Investment in affiliates	—			—			263,332			—			263,332
	Investment in subsidiaries on an equity basis	4,249,633			678,842			—			(4,928,475		)	—
	Premiums receivable	—			—			1,114,102			—			1,114,102
	Deferred acquisition costs	—			—			240,835			—			240,835
	Prepaid reinsurance premiums	—			—			192,694			—			192,694
	Securities lending collateral	—			—			5,337			—			5,337
	Loss reserves recoverable	—			—			375,882			—			375,882
	Paid losses recoverable	—			—			27,034			—			27,034
	Income taxes recoverable	—			—			10,597			—			10,597
	Deferred tax asset	—			—			30,847			—			30,847
	Receivable for investments sold	—			—			24,803			—			24,803
	Intangible assets	—			—			125,508			—			125,508
	Goodwill	—			—			195,897			—			195,897
	Accrued investment income	115			—			23,115			—			23,230
	Intercompany receivable	—			—			7,592			(7,592		)	—
	Other assets	2,758			—			214,226			—			216,984
	Total assets	$	4,305,471		$	678,862		$	11,135,381		$	(5,065,264	)	$	11,054,450
	Liabilities
	Reserve for losses and loss expenses	$	—		$	—		$	3,199,362		$	—		$	3,199,362
	Unearned premiums	—			—			1,452,179			—			1,452,179
	Reinsurance balances payable	—			—			101,426			—			101,426
	Securities lending payable	—			—			5,803			—			5,803
	Deferred tax liability	—			—			13,265			—			13,265
	Payable for investments purchased	—			—			123,556			—			123,556
	Accounts payable and accrued expenses	17,495			—			160,449			—			177,944
	Intercompany payable	7,534			58			—			(7,592		)	—
	Notes payable to operating affiliates	—			—			919,684			—			919,684
	Senior notes payable	247,333			—			—			—			247,333
	Debentures payable	350,000			—			247,761			(60,200		)	537,561
	Total liabilities	$	622,362		$	58		$	6,223,485		$	(67,792	)	$	6,778,113
	Redeemable noncontrolling interest	—			—			98,777			—			98,777
	Total shareholders' equity available to Validus	3,683,109			678,804			4,318,668			(4,997,472		)	3,683,109
	Noncontrolling interest	—			—			494,451			—			494,451
	Total liabilities, noncontrolling interests and shareholders' equity	$	4,305,471		$	678,862		$	11,135,381		$	(5,065,264	)	$	11,054,450
	(a)	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.
	(b)	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
	Condensed Consolidating Balance Sheet	Validus Holdings, Ltd.			Validus Holdings			Other			Consolidating Adjustments (b)			Validus Holdings, Ltd.
	As at December 31, 2014	(Parent Guarantor)			(UK) plc			Validus Holdings, Ltd.						Consolidated
					(Subsidiary Issuer)			Subsidiaries
								(Non-guarantor Subsidiaries) (a)
	Assets
	Fixed maturities, at fair value	$	—		$	—		$	5,592,931		$	(60,200	)	$	5,532,731
	Short-term investments, at fair value	—			—			1,051,074			—			$	1,051,074
	Other investments, at fair value	—			—			881,123			(68,112		)	$	813,011
	Cash and cash equivalents	29,798			81			547,361			—			$	577,240
	Restricted cash	—			—			173,003			—			173,003
	Total investments and cash	29,798			81			8,245,492			(128,312		)	8,147,059
	Investment in affiliates	—			—			261,483			—			261,483
	Investment in subsidiaries on an equity basis	4,140,770			656,738			—			(4,797,508		)	—
	Premiums receivable	—			—			707,647			—			707,647
	Deferred acquisition costs	—			—			161,295			—			161,295
Prepaid reinsurance premiums	—			—			81,983			—			81,983
Securities lending collateral	—			—			470			—			470
Loss reserves recoverable	—			—			377,466			—			377,466
Paid losses recoverable	—			—			38,078			—			38,078
Deferred tax asset	—			—			23,821			—			23,821
Receivable for investments sold	—			—			18,318			—			18,318
Intangible assets	—			—			126,924			—			126,924
Goodwill	—			—			195,897			—			195,897
Accrued investment income	—			—			24,865			—			24,865
Intercompany receivable	41,078			—			20			(41,098		)	—
Other assets	3,239			—			161,394			—			164,633
Total assets	$	4,214,885		$	656,819		$	10,425,153		$	(4,966,918	)	$	10,329,939
Liabilities
Reserve for losses and loss expenses	$	—		$	—		$	3,234,394		$	—		$	3,234,394
Unearned premiums	—			—			990,564			—			990,564
Reinsurance balances payable	—			—			127,128			—			127,128
Securities lending payable	—			—			936			—			936
Deferred tax liability	—			—			5,541			—			5,541
Payable for investments purchased	—			—			68,574			—			68,574
Accounts payable and accrued expenses	29,621			96			288,528			—			318,245
Intercompany payable	—			20			41,078			(41,098		)	—
Notes payable to operating affiliates	—			—			671,465			—			671,465
Senior notes payable	247,306			—			—			—			247,306
Debentures payable	350,000			—			249,477			(60,200		)	539,277
Total liabilities	$	626,927		$	116		$	5,677,685		$	(101,298	)	$	6,203,430
Redeemable noncontrolling interest	—			—			79,956			—			79,956
Total shareholders' equity available to Validus	3,587,958			656,703			4,208,917			(4,865,620		)	3,587,958
Noncontrolling interest	—			—			458,595			—			458,595
Total liabilities, noncontrolling interests and shareholders' equity	$	4,214,885		$	656,819		$	10,425,153		$	(4,966,918	)	$	10,329,939
(a)	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.
(b)	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
Condensed Consolidating	Validus Holdings, Ltd.			Validus Holdings			Other			Consolidating Adjustments (b)			Validus Holdings, Ltd.
Statement of Comprehensive Income	(Parent Guarantor)			(UK) plc			Validus Holdings, Ltd.						Consolidated
For the Three Months Ended March 31, 2015				(Subsidiary Issuer)			Subsidiaries
							(Non-guarantor Subsidiaries) (a)
Revenues
Net premiums earned	$	—		$	—		$	577,754		$	—		$	577,754
Net investment income	57			—			31,969			(1,005		)	31,021
Net realized gains on investments	—			—			4,169			—			4,169
Change in net unrealized (losses) gains on investments	(73		)	—			73,162			(885		)	72,204
Income from investment affiliate	—			—			2,776			—			2,776
Other insurance related income and other income	—			—			19,623			(14,791		)	4,832
Foreign exchange gains (losses)	510			—			(4,061		)	—			(3,551		)
Total revenues	$	494		$	—		$	705,392		$	(16,681	)	$	689,205
Expenses
Losses and loss expenses	—			—			240,929			—			240,929
Policy acquisition costs	—			—			98,636			—			98,636
General and administrative expenses	17,543			2			82,276			(14,793		)	85,028
Share compensation expenses	1,654			—			7,400			—			9,054
Finance expenses	11,858			—			8,475			(481		)	19,852
Total expenses	$	31,055		$	2		$	437,716		$	(15,274	)	$	453,499
(Loss) income before taxes, income from operating affiliates, (income) attributable to operating affiliate investors and equity in net earnings of subsidiaries	(30,561		)	(2		)	267,676			(1,407		)	235,706
Tax expense	—			—			(2,565		)	—			(2,565		)
Income from operating affiliates	—			—			2,453			—			2,453
(Income) attributable to operating affiliate investors	—			—			(23,206		)	—			(23,206		)
Equity in net earnings of subsidiaries	203,972			20,195			—			(224,167		)	—
Net income (loss)	$	173,411		$	20,193		$	244,358		$	(225,574	)	$	212,388
Net (income) attributable to noncontrolling interest	—			—			(38,977		)	—			(38,977		)
Net income available to Validus	$	173,411		$	20,193		$	205,381		$	(225,574	)	$	173,411
Other comprehensive (loss)	(4,085		)	—			(3,284		)	3,284			(4,085		)
Comprehensive income available to Validus	$	169,326		$	20,193		$	202,097		$	(222,290	)	$	169,326
(a)	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.
(b)	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
Condensed Consolidating	Validus Holdings, Ltd.			Validus Holdings			Other			Consolidating Adjustments (b)			Validus Holdings, Ltd.
Statement of Comprehensive Income	(Parent Guarantor)			(UK) plc			Validus Holdings, Ltd.						Consolidated
For the Three Months Ended March 31, 2014				(Subsidiary Issuer)			Subsidiaries
							(Non-guarantor Subsidiaries) (a)
Revenues
Net premiums earned	$	—		$	—		$	482,957		$	—		$	482,957
Net investment income	3			—			24,331			(972		)	23,362
Net realized gains on investments	—			—			3,740			—			3,740
Change in net unrealized gains on investments	—			—			51,465			4,228			55,693
Income from investment affiliate	—			—			5,348			—			5,348
Other insurance related income and other income	—			—			31,792			(17,962		)	13,830
Foreign exchange losses	(168		)	—			(6,310		)	—			(6,478		)
Total revenues	$	(165	)	$	—		$	593,323		$	(14,706	)	$	578,452
Expenses
Losses and loss expenses	—			—			162,671			—			162,671
Policy acquisition costs	—			—			85,649			—			85,649
General and administrative expenses	20,563			21			71,823			(17,962		)	74,445
Share compensation expenses	1,308			—			5,839			—			7,147
Finance expenses	11,823			—			4,557			(480		)	15,900
Total expenses	$	33,694		$	21		$	330,539		$	(18,442	)	$	345,812
(Loss) income before taxes, income from operating affiliates, (income) attributable to operating affiliate investors and equity in net earnings of subsidiaries	(33,859		)	(21		)	262,784			3,736			232,640
Tax benefit	—			—			40			—			40
Income from operating affiliates	—			—			4,927			—			4,927
(Income) attributable to operating affiliate investors	—			—			(31,710		)	—			(31,710		)
Equity in net earnings (losses) of subsidiaries	196,247			(748		)	—			(195,499		)	—
Net income (loss)	$	162,388		$	(769	)	$	236,041		$	(191,763	)	$	205,897
Net (income) attributable to noncontrolling interest	—			—			(43,509		)	—			(43,509		)
Net income (loss) available (attributable) to Validus	$	162,388		$	(769	)	$	192,532		$	(191,763	)	$	162,388
Other comprehensive income	462			—			462			(462		)	462
Comprehensive income (loss) available (attributable) to Validus	$	162,850		$	(769	)	$	192,994		$	(192,225	)	$	162,850
(a)	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.
(b)	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
Condensed Consolidating Statement of Cash Flows	Validus Holdings, Ltd.			Validus Holdings			Other			Consolidating Adjustments (b)			Validus Holdings, Ltd.
For the Three Months Ended March 31, 2015	(Parent Guarantor)			(UK) plc			Validus Holdings, Ltd.						Consolidated
				(Subsidiary Issuer)			Subsidiaries
							(Non-guarantor Subsidiaries) (a)
Net cash provided by (used in) operating activities	$	5,572		$	(61	)	$	(234,052	)	$	—		$	(228,541	)
Cash flows provided by (used in) investing activities
Proceeds on sales of investments	—			—			1,190,559			—			1,190,559
Proceeds on maturities of investments	—			—			93,732			—			93,732
Purchases of fixed maturities	(28,902		)	—			(1,134,805		)	—			(1,163,707		)
Purchases of short-term investments, net	—			—			(133,104		)	—			(133,104		)
Purchases of other investments	—			—			(29,291		)	—			(29,291		)
Increase in securities lending collateral	—			—			(4,867		)	—			(4,867		)
Investment in operating affiliates	—			—			(1,070		)	—			(1,070		)
Redemption from operating affiliates	—			—			24,150			—			24,150
Investment in investment affiliates	—			—			(19,700		)	—			(19,700		)
Increase in restricted cash	—			—			(13,420		)	—			(13,420		)
Return of capital from subsidiaries	100,000			—			—			(100,000		)	—
Net cash provided by (used in) investing activities	71,098			—			(27,816		)	(100,000		)	(56,718		)
Cash flows provided by (used in) financing activities
Proceeds on issuance of notes payable to operating affiliates	—			—			621,864			—			621,864
Repayments on notes payable to operating affiliates	—			—			(365,883		)	—			(365,883		)
Issuance of common shares, net	4,005			—			—			—			4,005
Purchases of common shares under share repurchase program	(58,108		)	—			—			—			(58,108		)
Dividends paid	(28,217		)	—			—			—			(28,217		)
Increase in securities lending payable	—			—			4,867			—			4,867
Third party investment in redeemable noncontrolling interest	—			—			15,700			—			15,700
Return of capital to parent	—			—			(100,000		)	100,000			—
Net cash (used in) provided by financing activities	(82,320		)	—			176,548			100,000			194,228
Effect of foreign currency rate changes on cash and cash equivalents	—			—			(15,080		)	—			(15,080		)
Net decrease in cash	(5,650		)	(61		)	(100,400		)	—			(106,111		)
Cash and cash equivalents, beginning of year	29,798			81			547,361			—			577,240
Cash and cash equivalents, end of year	$	24,148		$	20		$	446,961		$	—		$	471,129
(a)	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.
(b)	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
Condensed Consolidating Statement of Cash Flows	Validus Holdings, Ltd.			Validus Holdings			Other			Consolidating Adjustments (b)			Validus Holdings, Ltd.
For the Three Months Ended March 31, 2014	(Parent Guarantor)			(UK) plc			Validus Holdings, Ltd.						Consolidated
				(Subsidiary Issuer)			Subsidiaries
							(Non-guarantor Subsidiaries) (a)
Net cash provided by (used in) operating activities	$	267,177		$	—		$	(311,604	)	$	—		$	(44,427	)
Cash flows provided by (used in) investing activities
Proceeds on sales of investments	—			—			984,356			—			984,356
Proceeds on maturities of investments	—			—			124,716			—			124,716
Purchases of fixed maturities	—			—			(782,290		)	—			(782,290		)
Purchases of short-term investments, net	—			—			(107,437		)	—			(107,437		)
Sales of other investments	—			—			7,059			—			7,059
Increase in securities lending collateral	—			—			(1,485		)	—			(1,485		)
Redemption from operating affiliates	—			—			43,366			—			43,366
Decrease in restricted cash	—			—			91,274			—			91,274
Net cash provided by investing activities	—			—			359,559			—			359,559
Cash flows provided by (used in) financing activities
Proceeds on issuance of notes payable to operating affiliates	—			—			154,028			—			154,028
Repayments on notes payable to operating affiliates	—			—			(184,628		)	—			(184,628		)
Issuance of common shares, net	2,030			—			—			—			2,030
Purchases of common shares under share repurchase program	(197,339		)	—			—			—			(197,339		)
Dividends paid	(29,330		)	—			—			—			(29,330		)
Increase in securities lending payable	—			—			1,485			—			1,485
Third party redemption of redeemable noncontrolling interest	—			—			(10,496		)	—			(10,496		)
Net cash used in financing activities	(224,639		)	—			(39,611		)	—			(264,250		)
Effect of foreign currency rate changes on cash and cash equivalents	—			—			4,890			—			4,890
Net increase in cash	42,538			—			13,234			—			55,772
Cash and cash equivalents, beginning of year	20,385			—			713,763			—			734,148
Cash and cash equivalents, end of year	$	62,923		$	—		$	726,997		$	—		$	789,920
(a)	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.
(b)	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.

Subsequent_events

Subsequent events	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent events	Subsequent events
	Quarterly Dividend
	On May 7, 2015, the Company announced a quarterly cash dividend of $0.32 per each common share and $0.32 per common share equivalent for which each outstanding warrant is exercisable, payable on June 30, 2015 to holders of record on June 15, 2015.

Significant_accounting_policie

Significant accounting policies (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of preparation	These unaudited Consolidated Financial Statements (the "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, 2014, as filed with the U.S. Securities and Exchange Commission (the "SEC").
	In the opinion of management, these 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. The Consolidated Statement of Cash Flows for the three months ended March 31, 2014 includes a revision to increase net cash provided by investing activities by $94,768. There are no changes to the sub-totals of net cash used in operating activities, financing activities or the effect of foreign currency rate changes on cash and cash equivalents. This revision resulted in an increase in net cash of $94,768 for the three months ended March 31, 2014.
	The effect of this revision does not impact any per-share amounts or other components of equity or net assets in the statement of financial position in the prior period presented. The Company does not believe this revision is material to the prior period. The Company has revised these prior period amounts to provide comparability with current period cash flows. 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, 2015
Investments [Abstract]
Amortized cost (or 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, 2015 were as follows:
		Amortized Cost or Cost			Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
	U.S. government and government agency	$	768,112		$	3,867			$	(278	)		$	771,701
	Non-U.S. government and government agency	244,372			1,771				(2,610		)		243,533
	U.S. states, municipalities and political subdivisions	347,348			3,749				(254		)		350,843
	Agency residential mortgage-backed securities	522,951			11,725				(442		)		534,234
	Non-agency residential mortgage-backed securities	32,393			360				(645		)		32,108
	U.S. corporate	1,436,724			10,929				(1,507		)		1,446,146
	Non-U.S. corporate	509,705			4,827				(3,951		)		510,581
	Bank loans	464,761			1,417				(4,838		)		461,340
	Catastrophe bonds	129,711			556				(3,050		)		127,217
	Asset-backed securities	702,298			2,755				(788		)		704,265
	Commercial mortgage-backed securities	300,068			2,828				(385		)		302,511
	Total fixed maturities	5,458,443			44,784				(18,748		)		5,484,479
	Total short-term investments (a)	1,183,410			11				(79		)		1,183,342
	Other investments
	Fund of hedge funds	1,915			76				(921		)		1,070
	Preferred stock	2,945			60				—				3,005
	Hedge funds (b)	595,753			95,124				(129,559		)		561,318
	Private equity investments	48,140			5,831				(1,119		)		52,852
	Investment funds	253,453			561				—				254,014
	Mutual funds	6,199			3,537				—				9,736
	Total other investments	908,405			105,189				(131,599		)		881,995
	Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	7,550,258		$	149,984			$	(150,426	)		$	7,549,816
	Assets managed on behalf of operating affiliates (a)	(751,473		)	—				—				(751,473		)
	Catastrophe bonds	(129,711		)	(556		)		3,050				(127,217		)
	Noncontrolling interest (b)	(525,330		)	(79,346		)		116,603				(488,073		)
	Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	6,143,744		$	70,082			$	(30,773	)		$	6,183,053
	(a)	Included in the short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.
	(b)	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.
	The amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments at December 31, 2014 were as follows:
		Amortized Cost or Cost			Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
	U.S. government and government agency	$	759,232		$	1,755			$	(901	)		$	760,086
	Non-U.S. government and government agency	279,493			1,215				(1,980		)		278,728
	U.S. states, municipalities and political subdivisions	448,668			1,780				(825		)		449,623
	Agency residential mortgage-backed securities	520,685			9,697				(1,151		)		529,231
	Non-agency residential mortgage-backed securities	37,954			369				(516		)		37,807
	U.S. corporate	1,500,963			3,960				(5,217		)		1,499,706
	Non-U.S. corporate	564,386			2,765				(3,989		)		563,162
	Bank loans	457,537			200				(8,733		)		449,004
	Catastrophe bonds	75,822			768				(926		)		75,664
	Asset-backed securities	647,422			1,250				(1,190		)		647,482
	Commercial mortgage-backed securities	242,332			598				(692		)		242,238
	Total fixed maturities	5,534,494			24,357				(26,120		)		5,532,731
	Total short-term investments (a)	1,051,222			13				(161		)		1,051,074
	Other investments
	Fund of hedge funds	2,570			125				(920		)		1,775
	Preferred stock	6,535			—				(201		)		6,334
	Hedge funds (b)	570,371			60,792				(134,203		)		496,960
	Private equity investments	48,995			4,987				(611		)		53,371
	Investment funds	244,506			437				(111		)		244,832
	Mutual funds	6,199			3,540				—				9,739
	Total other investments	879,176			69,881				(136,046		)		813,011
	Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	7,464,892		$	94,251			$	(162,327	)		$	7,396,816
	Assets managed on behalf of operating affiliates (a)	(696,924		)	—				—				(696,924		)
	Catastrophe bonds	(75,822		)	(768		)		926				(75,664		)
	Noncontrolling interest (b)	(502,830		)	(48,446		)		120,782				(430,494		)
	Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	6,189,316		$	45,037			$	(40,619	)		$	6,193,734
	(a)	Included in the short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.
	(b)	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.
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, 2015 and December 31, 2014.
		March 31, 2015						December 31, 2014
		Estimated Fair Value			% of Total			Estimated Fair Value				% of Total
	AAA	$	2,473,674		45.1	%		$	2,494,239			45.1	%
	AA	660,150			12	%		848,226				15.4	%
	A	1,087,156			19.8	%		1,086,091				19.6	%
	BBB	570,464			10.4	%		505,208				9.1	%
	Total investment-grade fixed maturities	4,791,444			87.3	%		4,933,764				89.2	%
	BB	307,561			5.6	%		362,972				6.6	%
	B	247,983			4.5	%		145,240				2.6	%
	CCC	4,365			0.1	%		12,733				0.2	%
	CC	3,286			0.1	%		3,926				0.1	%
	C	—			—	%		1,344				—	%
	D/NR	129,840			2.4	%		72,752				1.3	%
	Total non-investment grade fixed maturities	693,035			12.7	%		598,967				10.8	%
	Total fixed maturities	$	5,484,479		100	%		$	5,532,731			100	%
Fixed maturities investments by contractual maturity	The amortized cost and estimated fair value amounts for fixed maturities held at March 31, 2015 and December 31, 2014 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, 2015							December 31, 2014
		Amortized Cost			Estimated Fair Value				Amortized Cost				Estimated Fair Value
	Due in one year or less	$	291,651		$	292,276			$	312,843			$	313,248
	Due after one year through five years	2,921,246			2,928,600				3,163,225				3,159,200
	Due after five years through ten years	571,599			572,771				497,175				491,870
	Due after ten years	116,237			117,716				112,858				111,655
		3,900,733			3,911,363				4,086,101				4,075,973
	Asset-backed and mortgage-backed securities	1,557,710			1,573,116				1,448,393				1,456,758
	Total fixed maturities	$	5,458,443		$	5,484,479			$	5,534,494			$	5,532,731
Net investment income	Net investment income was derived from the following sources:
		Three Months Ended
		March 31, 2015			March 31, 2014
	Fixed maturities and short-term investments	$	29,239		$	23,297
	Other investments	3,188			—
	Restricted cash and cash and cash equivalents	435			1,957
	Securities lending income	3			2
	Total gross investment income	32,865			25,256
	Investment expenses	(1,844		)	(1,894		)
	Total net investment income	$	31,021		$	23,362
Analysis of net realized gains and the change in net unrealized gains on investments	The following represents an analysis of net realized gains and the change in net unrealized gains on investments:
		Three Months Ended
		March 31, 2015			March 31, 2014
	Fixed maturities, short-term and other investments
	Gross realized gains	$	6,309		$	5,296
	Gross realized (losses)	(2,140		)	(1,556		)
	Net realized gains on investments	4,169			3,740
	Change in net unrealized gains on investments (a)	72,204			55,693
	Total net realized and change in net unrealized gains on investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	76,373			59,433
	Assets managed on behalf of operating affiliates	—			—
	Catastrophe bonds	2,336			797
	Noncontrolling interest (a)	(35,079		)	(42,002		)
	Total net realized and change in net unrealized gains on investments excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	43,630		$	18,228
	(a)	Includes the change in net unrealized gains 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 loss (income) attributable to noncontrolling interest.
Investments pledged as collateral under credit facilities	The following tables outline investments and cash 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, 2015
	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			268,907				400,774
	$30,000 secured bi-lateral letter of credit facility		30,000			14,747				27,019
	Talbot FAL facility		25,000			25,000				31,221
	PaCRe senior secured letter of credit facility		10,000			39				—
	AlphaCat Re secured letter of credit facility		30,000			30,000				30,097
	IPC bi-lateral facility		25,000			12,543				100,549
	$230,000 Flagstone bi-lateral facility		230,000			209,070				373,664
	Total		$	1,275,000		$	560,306			$	963,324
			December 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			276,455				395,750
	$200,000 secured bi-lateral letter of credit facility		200,000			15,649				35,645
	Talbot FAL facility		25,000			25,000				31,048
	PaCRe senior secured letter of credit facility		10,000			294				—
	AlphaCat Re secured letter of credit facility		30,000			30,000				30,078
	IPC bi-lateral facility		40,000			15,897				99,437
	$375,000 Flagstone bi-lateral facility		375,000			198,389				430,782
	Total		$	1,605,000		$	561,684			$	1,022,740

Fair_value_measurements_Tables

Fair value measurements (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair value hierarchy - allocation of investments	At March 31, 2015, 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	$	—		$	771,701		$	—		$	771,701
	Non-U.S. government and government agency	—			243,533			—			243,533
	U.S. states, municipalities and political subdivisions	—			350,843			—			350,843
	Agency residential mortgage-backed securities	—			534,234			—			534,234
	Non-agency residential mortgage-backed securities	—			32,108			—			32,108
	U.S. corporate	—			1,446,146			—			1,446,146
	Non-U.S. corporate	—			510,581			—			510,581
	Bank loans	—			381,621			79,719			461,340
	Catastrophe bonds	—			124,217			3,000			127,217
	Asset-backed securities	—			704,265			—			704,265
	Commercial mortgage-backed securities	—			302,511			—			302,511
	Total fixed maturities	—			5,401,760			82,719			5,484,479
	Total short-term investments (a)	1,084,139			92,389			6,814			1,183,342
	Other investments
	Fund of hedge funds	—			—			1,070			1,070
	Preferred stock	—			3,005			—			3,005
	Hedge funds (b)	—			—			561,318			561,318
	Private equity investments	—			—			52,852			52,852
	Investment funds	—			91,131			162,883			254,014
	Mutual funds	—			9,736			—			9,736
	Total other investments	—			103,872			778,123			881,995
	Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	1,084,139		$	5,598,021		$	867,656		$	7,549,816
	Assets managed on behalf of operating affiliates (a)	(751,473		)	—			—			(751,473		)
	Catastrophe bonds	—			(124,217		)	(3,000		)	(127,217		)
	Noncontrolling interest (b)	—			—			(488,073		)	(488,073		)
	Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	332,666		$	5,473,804		$	376,583		$	6,183,053
	(a)	Included in the short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.
	(b)	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.
	At December 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	$	—		$	760,086		$	—		$	760,086
	Non-U.S. government and government agency	—			278,728			—			278,728
	U.S. states, municipalities and political subdivisions	—			449,623			—			449,623
	Agency residential mortgage-backed securities	—			529,231			—			529,231
	Non-agency residential mortgage-backed securities	—			37,807			—			37,807
	U.S. corporate	—			1,499,706			—			1,499,706
	Non-U.S. corporate	—			563,162			—			563,162
	Bank loans	—			416,256			32,748			449,004
	Catastrophe bonds	—			70,664			5,000			75,664
	Asset-backed securities	—			647,482			—			647,482
	Commercial mortgage-backed securities	—			242,238			—			242,238
	Total fixed maturities	—			5,494,983			37,748			5,532,731
	Total short-term investments (a)	942,716			108,358			—			1,051,074
	Other investments
	Fund of hedge funds	—			—			1,775			1,775
	Preferred stock	—			6,334			—			6,334
	Hedge funds (b)	—			—			496,960			496,960
	Private equity investments	—			—			53,371			53,371
	Investment fund	—			140,045			104,787			244,832
	Mutual funds	—			9,739			—			9,739
	Total other investments	—			156,118			656,893			813,011
	Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	942,716		$	5,759,459		$	694,641		$	7,396,816
	Assets managed on behalf of operating affiliates (a)	(696,924		)	—			—			(696,924		)
	Catastrophe bonds	—			(70,664		)	(5,000		)	(75,664		)
	Noncontrolling interest (b)	—			—			(430,494		)	(430,494		)
	Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$	245,792		$	5,688,795		$	259,147		$	6,193,734
	(a)	Included in the short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.
	(b)	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.
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, 2015 and 2014:
		Three Months Ended
		31-Mar-15			31-Mar-14
	Level 3 investments - Beginning of period	$	694,641		$	576,871
	Purchases	145,789			—
	Sales	(7,602		)	(3,589		)
	Settlements	(3,995		)	—
	Net realized (losses) gains	(11		)	10
	Change in net unrealized gains	38,834			49,326
	Transfers into Level 3	—			6,703
	Level 3 investments - End of period	$	867,656		$	629,321
	Catastrophe Bonds	(3,000		)	—
	Noncontrolling interest (a)	(488,073		)	(531,403		)
	Level 3 investments - End of period excluding catastrophe bonds and noncontrolling interest	$	376,583		$	97,918
	(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, 2015
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, 2015 and December 31, 2014:
		31-Mar-15			31-Dec-14
	Investment affiliates	$	85,982		$	63,506
	Operating affiliates	177,350			197,977
	Investments in affiliates	$	263,332		$	261,483
Summary of notes payable to operating affiliates	The following tables present a reconciliation of the beginning and ending notes payable to operating affiliates for the three months ended March 31, 2015 and 2014:
		Three Months Ended March 31, 2015
		AlphaCat 2013			AlphaCat 2014				AlphaCat 2015				AlphaCat ILS funds			Total
	As at December 31, 2014	$	—		$	157,384			$	—			$	514,081		$	671,465
	Issuance of notes payable to operating affiliates	—			—				137,540				484,324			621,864
	Redemption of notes payable to operating affiliates	—			(148,893		)		—				(216,990		)	(365,883		)
	Foreign exchange gain	—			(310		)		(246		)		(7,206		)	(7,762		)
	As at March 31, 2015	$	—		$	8,181			$	137,294			$	774,209		$	919,684
		Three Months Ended March 31, 2014
		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
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, 2015 and 2014:
		Three Months Ended
		March 31,			March 31,
		2015			2014
	AlphaCat 2013	$	1		$	(10,476	)
	AlphaCat 2014	(156		)	(10,789		)
	AlphaCat 2015	(8,773		)	—
	AlphaCat ILS funds	(14,278		)	(10,445		)
	(Income) attributable to operating affiliate investors	$	(23,206	)	$	(31,710	)
Investment affiliate
Schedule of Equity Method Investments [Line Items]
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 affiliates balance for the three months ended March 31, 2015 and 2014:
		Three Months Ended
		March 31,			March 31,
		2015			2014
	Investment affiliates, beginning of period	$	63,506		$	34,500
	Capital contributions	19,700			—
	Income from investment affiliate	2,776			5,348
	Investment affiliates, end of period	$	85,982		$	39,848
Schedule of equity method investments	The following table presents the Company's investment in the Partnerships as at March 31, 2015:
		Investment in investment affiliate
		Investment at cost			Voting ownership %			Equity Ownership			Carrying Value
	Aquiline Financial Services Fund II L.P.	$	56,563		—	%		8.1	%		$	71,844
	Aquiline Financial Services Fund III L.P.	$	14,138		—	%		13.7	%		$	14,138
	Total	$	70,701								$	85,982
	The following table presents the Company's investment in the Partnership as at December 31, 2014:
		Investment in investment affiliate
		Investment at cost			Voting ownership %			Equity Ownership			Carrying Value
	Aquiline Financial Services Fund II L.P.	$	51,001		—	%		8.1	%		$	63,506
Operating affiliates
Schedule of Equity Method Investments [Line Items]
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, 2015 and 2014:
		Three Months Ended March 31, 2015
		AlphaCat Re 2011			AlphaCat Re 2012				AlphaCat 2013				AlphaCat 2014			AlphaCat 2015			AlphaCat ILS funds			Total
	As at December 31, 2014	$	4,606		$	735			$	1,068			$	28,085		$	25,600		$	137,883		$	197,977
	Purchase of shares	—			—				—				—			—			1,070			1,070
	Return of investment	—			—				—				(24,150		)	—			—			(24,150		)
	Income from operating affiliates	(10		)	(25		)		(14		)		(100		)	1,316			1,286			2,453
	As at March 31, 2015	$	4,596		$	710			$	1,054			$	3,835		$	26,916		$	140,239		$	177,350
		Three Months Ended March 31, 2014
		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 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
Schedule of equity method investments	The following table presents the Company's investments in AlphaCat Re 2011, AlphaCat Re 2012, AlphaCat 2013, AlphaCat 2014, AlphaCat 2015 and the AlphaCat ILS funds in the Consolidated Financial Statements as at March 31, 2015:
		Investment in operating affiliates
		Cost			Voting ownership %			Equity ownership %			Carrying value
	AlphaCat Re 2011	$	4,596		43.7	%		22.3	%		$	4,596
	AlphaCat Re 2012	710			49	%		37.9	%		710
	AlphaCat 2013	1,054			40.9	%		19.7	%		1,054
	AlphaCat 2014	3,835			42.3	%		19.6	%		3,835
	AlphaCat 2015	25,600			40	%		20	%		26,916
	AlphaCat ILS funds	134,161			n/a			(a)			140,239
	Total	$	169,956								$	177,350
	(a)	Equity ownership in the funds was 7.6%, 25.2% and 9.1%, respectively as at March 31, 2015.
	The following table presents the Company's investments in AlphaCat Re 2011, AlphaCat Re 2012, AlphaCat 2013, AlphaCat 2014, AlphaCat 2015 and the AlphaCat ILS funds in the Consolidated Financial Statements as at December 31, 2014:
		Investment in operating affiliates
		Cost			Voting ownership %			Equity ownership %			Carrying value
	AlphaCat Re 2011	$	4,606		43.7	%		22.3	%		$	4,606
	AlphaCat Re 2012	735			49	%		37.9	%		735
	AlphaCat 2013	1,068			40.9	%		19.7	%		1,068
	AlphaCat 2014	22,000			42.3	%		19.6	%		28,085
	AlphaCat 2015	25,600			40	%		20	%		25,600
	AlphaCat ILS funds	133,091			n/a			(a)			137,883
	Total	$	187,100								$	197,977
	(a)	Equity ownership in the funds was 7.9%, 39.7% and 9.1%, respectively as at December 31, 2014.

Noncontrolling_interest_Tables

Noncontrolling interest (Tables)	3 Months Ended
	Mar. 31, 2015
Noncontrolling Interest [Abstract]
Noncontrolling interest	The following tables present a reconciliation of the beginning and ending balances of redeemable noncontrolling interest and noncontrolling interest for the three months ended March 31, 2015 and 2014:
		Three Months Ended March 31, 2015
		Redeemable noncontrolling interest			Noncontrolling interest		Total
	As at December 31, 2014	$	79,956		$	458,595	$	538,551
	Issuance of shares	15,700			—		15,700
	Income attributable to noncontrolling interest	3,121			35,856		38,977
	As at March 31, 2015	$	98,777		$	494,451	$	593,228
		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 noncontrolling interest	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

Derivative_instruments_Tables

Derivative instruments (Tables)	3 Months Ended
	Mar. 31, 2015
Derivative instruments designated as a fair value hedge
Derivative [Line Items]
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, 2015 and 2014:
			Three Months Ended
	Foreign currency forward contracts		March 31, 2015			March 31, 2014
	Amount of (loss) gain recognized in income on derivative		$	(10,113	)	$	3,303
	Amount of gain (loss) on hedged item recognized in income attributable to risk being hedged		$	10,113		$	(3,303	)
	Amount of gain (loss) recognized in income on derivative (ineffective portion)		$	—		$	—
Derivative instruments designated as a cash flow hedge
Derivative [Line Items]
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 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, 2015 and 2014:
			Three Months Ended
	Interest rate swap contracts		March 31, 2015			March 31, 2014
	Amount of effective portion recognized in other comprehensive income		$	4,040		$	3,208
	Amount of effective portion subsequently reclassified to earnings		$	(3,239	)	$	(3,208	)
	Amount of ineffective portion excluded from effectiveness testing		$	(801	)	$	—
Not designated as hedging instruments
Derivative [Line Items]
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 not designated as hedging instruments on the Consolidated Balance Sheets at March 31, 2015 and December 31, 2014:
			As at March 31, 2015								As at December 31, 2014
	Derivatives not 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		$	22,039		$	—		$	225	$	26,755	$	1,685	$	—
	(a)	Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses respectively on the Consolidated Balance Sheets. The net impact on earnings during the three months ended March 31, 2015, recognized in income within other income, relating to the foreign currency forward contract that was not designated as a hedging instrument was $1 (2014: $nil).
Designated as hedging instruments
Derivative [Line Items]
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, 2015 and December 31, 2014:
			As at March 31, 2015								As at December 31, 2014
	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		$	202,779		$	584		$	9,384	$	189,026	$	401	$	3,136
	Interest rate swap contracts		$	552,263		$	21		$	1,915	$	552,263	$	25	$	1,169
	(a)	Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses respectively on the Consolidated Balance Sheets.

Reserve_for_losses_and_loss_ex1

Reserve for losses and loss expenses (Tables)	3 Months Ended
	Mar. 31, 2015
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, 2015 and 2014:
		Three Months Ended
		March 31,			March 31,
		2015			2014
	Reserve for losses and loss expenses, beginning of period	$	3,234,394		$	3,030,399
	Losses and loss expenses recoverable	(377,466		)	(370,154		)
	Net reserves for losses and loss expenses, beginning of period	2,856,928			2,660,245
	Increase (decrease) in net reserves for losses and loss expenses in respect of losses occurring in:
	Current year	324,488			202,086
	Prior years	(83,559		)	(39,415		)
	Total incurred losses and loss expenses	240,929			162,671
	Less net losses and loss expenses paid in respect of losses occurring in:
	Current year	(13,100		)	(7,967		)
	Prior years	(236,003		)	(250,115		)
	Total net paid losses	(249,103		)	(258,082		)
	Foreign exchange (gain) loss	(25,274		)	11,818
	Net reserve for losses and loss expenses, end of period	2,823,480			2,576,652
	Losses and loss expenses recoverable	375,882			348,407
	Reserve for losses and loss expenses, end of period	$	3,199,362		$	2,925,059
	Incurred losses and loss expenses comprise:
		Three Months Ended
		March 31,			March 31,
		2015			2014
	Gross losses and loss expenses	$	264,796		$	181,975
	Reinsurance recoverable	(23,867		)	(19,304		)
	Net incurred losses and loss expenses	$	240,929		$	162,671

Reinsurance_Tables

Reinsurance (Tables)	3 Months Ended
	Mar. 31, 2015
Reinsurance Disclosures [Abstract]
Reinsurance recoverables by reinsurer	Reinsurance recoverables by reinsurer as at March 31, 2015 and December 31, 2014 are as follows:
		March 31, 2015					December 31, 2014
		Reinsurance Recoverable			% of Total		Reinsurance Recoverable		% of Total
	Top 10 reinsurers	$	317,056		78.7	%	$	312,205	75.1	%
	Other reinsurers’ balances > $1 million	79,034			19.6	%	94,247		22.7	%
	Other reinsurers’ balances < $1 million	6,826			1.7	%	9,092		2.2	%
	Total	$	402,916		100	%	$	415,544	100	%
			March 31, 2015
	Top 10 Reinsurers		Rating	Reinsurance Recoverable			% of Total
	Swiss Re		AA-	$	79,535		19.7	%
	Lloyd's Syndicates		A+	61,406			15.2	%
	Everest Re		A+	46,105			11.4	%
	Hannover Re		AA-	41,330			10.3	%
	Fully Collateralized		NR	29,979			7.4	%
	Munich Re		AA-	21,632			5.4	%
	Transatlantic Re		A+	11,605			2.9	%
	XL Re		A+	9,897			2.5	%
	Merrimack Mutual Fire Insurance		A+	8,076			2	%
	Hamilton Re		A-	7,491			1.9	%
	Total			$	317,056		78.7	%
	NR: Not rated
			December 31, 2014
	Top 10 Reinsurers		Rating	Reinsurance Recoverable			% of Total
	Swiss Re		AA-	$	70,848		17	%
	Lloyd's Syndicates		A+	62,318			15	%
	Everest Re		A+	51,425			12.4	%
	Hannover Re		AA-	40,927			9.8	%
	Fully Collateralized		NR	23,315			5.6	%
	Munich Re		AA-	19,384			4.7	%
	Transatlantic Re		A+	12,418			3	%
	XL Re		A+	11,114			2.7	%
	Berkshire Hathaway Homestate		AA+	10,372			2.5	%
	Merrimack Mutual Fire Insurance		A+	10,084			2.4	%
	Total			$	312,205		75.1	%
	NR: Not rated

Share_capital_Tables

Share capital (Tables)	3 Months Ended
	Mar. 31, 2015
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, 2014	155,554,224
	Restricted share awards vested, net of shares withheld	14,447
	Restricted share units vested, net of shares withheld	1,997
	Options exercised	704,974
	Warrants exercised	473,817
	Direct issuance of common stock	324
	Common shares issued, March 31, 2015	156,749,783
	Treasury shares, March 31, 2015	(73,114,868	)
	Common shares outstanding, March 31, 2015	83,634,915
		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

Stock_plans_Tables

Stock plans (Tables)	3 Months Ended
	Mar. 31, 2015
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, 2015 was as follows:
		Options		Weighted Average Grant Date Fair Value				Weighted Average Grant Date Exercise Price
	Options outstanding, December 31, 2014	1,160,057		$	7.12			$	17.74
	Options exercised	(1,017,165	)	7.36				16.55
	Options outstanding, March 31, 2015	142,892		$	5.45			$	26.24
	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
Restricted shares awards, activity during the period	Activity with respect to unvested restricted share awards for the three months ended March 31, 2015 was as follows:
		Restricted Share Awards		Weighted Average Grant Date Fair Value
	Restricted share awards outstanding, December 31, 2014	2,858,711		$	35.81
	Restricted share awards vested	(19,682	)	32.25
	Restricted share awards forfeited	(2,410	)	41.5
	Restricted share awards outstanding, March 31, 2015	2,836,619		$	35.83
	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
Restricted share units, activity during the period	Activity with respect to unvested restricted share units for the three months ended March 31, 2015 was as follows:
		Restricted Share Units		Weighted Average Grant Date Fair Value
	Restricted share units outstanding, December 31, 2014	103,484		$	36.54
	Restricted share units vested	(1,997	)	38.24
	Restricted share units issued in lieu of cash dividends	747		36.54
	Restricted share units forfeited	(893	)	35.42
	Restricted share units outstanding, March 31, 2015	101,341		$	36.51
	Activity with respect to unvested restricted share units for the three months ended March 31, 2014 was as follows:
		Restricted		Weighted Average Grant Date Fair Value
		Share Units
	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
Performance share awards, activity during the period	Activity with respect to unvested performance share awards for the three months ended March 31, 2015 was as follows:
		Performance Share Awards		Weighted Average Grant Date Fair Value
	Performance share awards outstanding, December 31, 2014	106,369		$	36.03
	Performance share awards outstanding, March 31, 2015	106,369		$	36.03
	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
Total share compensation expenses	The breakdown of share compensation expenses by award type for the periods indicated was as follows:
		Three Months Ended
		March 31,			March 31,
		2015			2014
	Restricted share awards	$	8,479		$	7,001
	Restricted share units	262			166
	Performance share awards	313			(20		)
	Total	$	9,054		$	7,147

Debt_and_financing_arrangement1

Debt and financing arrangements (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Schedule of financing structure	The financing structure at March 31, 2015 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	134,011			134,011				134,011
	Flagstone 2007 Junior Subordinated Deferrable Debentures	113,750			113,750				113,750
	Total debentures payable	597,761			537,561				537,561
	2010 Senior Notes due 2040	250,000			250,000				247,333
	Total debentures and senior notes payable	847,761			787,561				784,894
	$400,000 syndicated unsecured letter of credit facility	400,000			—				—
	$525,000 syndicated secured letter of credit facility	525,000			268,907				—
	$30,000 secured bi-lateral letter of credit facility	30,000			14,747				—
	Talbot FAL facility	25,000			25,000				—
	PaCRe senior secured letter of credit facility	10,000			39				—
	AlphaCat Re secured letter of credit facility	30,000			30,000				—
	IPC bi-lateral facility	25,000			12,543				—
	$230,000 Flagstone bi-lateral facility	230,000			209,070				—
	Total credit and other facilities	1,275,000			560,306				—
	Total debt and financing arrangements	$	2,122,761		$	1,347,867			$	784,894
	The financing structure at December 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	135,727			135,727				135,727
	Flagstone 2007 Junior Subordinated Deferrable Debentures	113,750			113,750				113,750
	Total debentures payable	599,477			539,277				539,277
	2010 Senior Notes due 2040	250,000			250,000				247,306
	Total debentures and senior notes payable	849,477			789,277				786,583
	$400,000 syndicated unsecured letter of credit facility	400,000			—				—
	$525,000 syndicated secured letter of credit facility	525,000			276,455				—
	$200,000 secured bi-lateral letter of credit facility	200,000			15,649				—
	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			30,000				—
	IPC bi-lateral facility	40,000			15,897				—
	$375,000 Flagstone bi-lateral facility	375,000			198,389				—
	Total credit and other facilities	1,605,000			561,684				—
	Total debt and financing arrangements	$	2,454,477		$	1,350,961			$	786,583
	(a)	Indicates utilization of commitment amount, not necessarily drawn borrowings.
Debt Instruments [Line Items]
Components of finance expenses	Finance expenses consist of interest on the junior subordinated deferrable debentures and senior notes, the amortization of debt offering costs, credit facilities fees, bank charges, AlphaCat financing fees and Talbot FAL costs as follows:
		Three Months Ended
		March 31,			March 31,
		2015			2014
	2006 Junior Subordinated Deferrable Debentures	$	2,187		$	2,187
	2007 Junior Subordinated Deferrable Debentures	1,809			1,809
	Flagstone 2006 Junior Subordinated Deferrable Debentures	2,218			2,223
	Flagstone 2007 Junior Subordinated Deferrable Debentures	1,758			1,750
	2010 Senior Notes due 2040	5,597			5,597
	Credit facilities	1,707			1,559
	Bank charges	98			113
	AlphaCat ILS funds fees (a)	4,428			677
	Talbot FAL Facility	50			(15		)
	Total finance expenses	$	19,852		$	15,900
	(a)	Includes finance expenses incurred by AlphaCat Managers, Ltd. in relation to fund raising for the AlphaCat ILS funds, AlphaCat 2015, AlphaCat 2014 and AlphaCat 2013.
At Issuance
Debt Instruments [Line Items]
Summary of key terms of 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	%	(a)	Quarterly
	Flagstone 2006 Junior Subordinated Deferrable Debentures	August 23, 2006	$	134,011	September 15, 2036	3.54	%	(b)	Quarterly
	2007 Junior Subordinated Deferrable Debentures	June 21, 2007	$	200,000	June 15, 2037	8.48	%	(a)	Quarterly
	Flagstone 2007 Junior Subordinated Deferrable Debentures	June 8, 2007	$	88,750	July 30, 2037	3	%	(b)	Quarterly
	Flagstone 2007 Junior Subordinated Deferrable Debentures	September 20, 2007	$	25,000	September 15, 2037	3.1	%	(b)	Quarterly
	2010 Senior Notes due 2040	January 26, 2010	$	250,000	January 26, 2040	8.875	%	(a)	Semi-annually in arrears
	(a)	Fixed interest rate.
	(b)	Variable interest rate is the three-month LIBOR, reset quarterly, plus spread as noted in the table.
Outstanding
Debt Instruments [Line Items]
Summary of key terms of 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 March 31, 2015:
	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	$	134,011	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, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of changes in accumulated other comprehensive loss	The changes in accumulated other comprehensive loss, by component for the three months ended March 31, 2015 and 2014 is as follows:
	Three Months Ended March 31, 2015	Foreign currency items			Decrease in minimum pension liability			Losses on cash flow hedge			Total
	Balance beginning of period, net of tax	$	(8,118	)	$	(210	)	$	(228	)	$	(8,556	)
	Net current period other comprehensive income, net of tax	(3,019		)	(265		)	(801		)	(4,085		)
	Balance end of period, net of tax	$	(11,137	)	$	(475	)	$	(1,029	)	$	(12,641	)
	Three Months Ended March 31, 2014	Foreign currency items			Total
	Balance beginning of period, net of tax	$	(617	)	$	(617	)
	Net current period other comprehensive income, net of tax	462			462
	Balance end of period, net of tax	$	(155	)	$	(155	)

Commitments_and_contingencies_

Commitments and contingencies (Tables)	3 Months Ended
	Mar. 31, 2015
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:
		2015 Underwriting Year		2014 Underwriting Year
	Talbot FAL facility	$	25,000	$	25,000
	Group funds	570,100		450,000
	Total	$	595,100	$	475,000

Earnings_per_share_Tables

Earnings per share (Tables)	3 Months Ended
	Mar. 31, 2015
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, 2015 and 2014:
		Three Months Ended
		March 31,			March 31,
		2015			2014
	Basic earnings per share
	Net income	$	212,388		$	205,897
	Income attributable to noncontrolling interest	(38,977		)	(43,509		)
	Net income available to Validus	173,411			162,388
	Less: Dividends and distributions declared on outstanding warrants	(1,405		)	(1,552		)
	Income available to common shareholders	$	172,006		$	160,836
	Weighted average number of common shares outstanding	83,251,243			93,451,999
	Basic earnings per share available to common shareholders	$	2.07		$	1.72
	Earnings per diluted share
	Net income	$	212,388		$	205,897
	Income attributable to noncontrolling interest	(38,977		)	(43,509		)
	Net income available to Validus	173,411			162,388
	Less: Dividends and distributions declared on outstanding warrants	—			—
	Income available to common shareholders	$	173,411		$	162,388
	Weighted average number of common shares outstanding	83,251,243			93,451,999
	Share equivalents:
	Warrants	2,745,066			2,716,010
	Stock options	473,424			750,369
	Unvested restricted shares	1,113,396			881,141
	Weighted average number of diluted common shares outstanding	87,583,129			97,799,519
	Earnings per diluted share available to common shareholders	$	1.98		$	1.66

Segment_information_Tables

Segment information (Tables)	3 Months Ended
	Mar. 31, 2015
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, 2015		Validus Re Segment				AlphaCat Segment				Talbot Segment				Western World Segment				Corporate & Eliminations				Total
	Underwriting income
	Gross premiums written		$	711,212			$	102,564			$	270,077			$	56,947			$	(21,302	)		$	1,119,498
	Reinsurance premiums ceded		(113,296		)		(4,538		)		(91,075		)		(3,233		)		21,302				(190,840		)
	Net premiums written		597,916				98,026				179,002				53,714				—				928,658
	Change in unearned premiums		(344,828		)		(63,831		)		43,587				14,168				—				(350,904		)
	Net premiums earned		253,088				34,195				222,589				67,882				—				577,754
	Underwriting deductions
	Losses and loss expenses		113,128				(844		)		78,128				50,517				—				240,929
	Policy acquisition costs		42,094				3,660				49,104				4,279				(501		)		98,636
	General and administrative expenses		19,509				4,002				36,494				10,627				14,396				85,028
	Share compensation expenses		2,578				149				2,957				477				2,893				9,054
	Total underwriting deductions		177,309				6,967				166,683				65,900				16,788				433,647
	Underwriting income (loss)		$	75,779			$	27,228			$	55,906			$	1,982			$	(16,788	)		$	144,107
	Net investment income		18,776				1,585				6,305				5,303				(948		)		31,021
	Other insurance related income (loss)		315				5,771				54				263				(1,571		)		4,832
	Finance expenses		(3,871		)		(4,516		)		(87		)		—				(11,378		)		(19,852		)
	Operating income (loss) before taxes, income from operating affiliates and (income) attributable to operating affiliate investors		90,999				30,068				62,178				7,548				(30,685		)		160,108
	Tax benefit (expense)		1,880				—				(883		)		(3,723		)		161				(2,565		)
	Income from operating affiliates		—				2,453				—				—				—				2,453
	(Income) attributable to operating affiliate investors		—				(23,206		)		—				—				—				(23,206		)
	Net operating income (loss)		$	92,879			$	9,315			$	61,295			$	3,825			$	(30,524	)		$	136,790
	Net realized gains (losses) on investments		1,809				(11		)		871				1,500				—				4,169
	Change in net unrealized gains (losses) on investments		20,578				37,535				7,911				7,138				(958		)		72,204
	Income from investment affiliate		1,933				—				—				843				—				2,776
	Foreign exchange (losses) gains		(5,024		)		(95		)		(485		)		—				2,053				(3,551		)
	Net income (loss)		$	112,175			$	46,744			$	69,592			$	13,306			$	(29,429	)		$	212,388
	Net (income) attributable to noncontrolling interest		—				(38,977		)		—				—				—				(38,977		)
	Net income (loss) available (attributable) to Validus		$	112,175			$	7,767			$	69,592			$	13,306			$	(29,429	)		$	173,411
	Selected ratios (a):
	Net premiums written / Gross premiums written		84.1		%		95.6		%		66.3		%		94.3		%						83		%
	Losses and loss expenses		44.7		%		(2.5		)%		35.1		%		74.4		%						41.7		%
	Policy acquisition costs		16.7		%		10.7		%		22.1		%		6.3		%						17.1		%
	General and administrative expenses (b)		8.7		%		12.1		%		17.7		%		16.4		%						16.3		%
	Expense ratio		25.4		%		22.8		%		39.8		%		22.7		%						33.4		%
	Combined ratio		70.1		%		20.3		%		74.9		%		97.1		%						75.1		%
	Total assets		$	4,567,449			$	1,954,260			$	2,933,104			$	1,512,848			$	86,789			$	11,054,450
	(a)	Ratios are based on net premiums earned.
	(b)	The general and administrative expenses ratio includes share compensation expenses.
	Three Months Ended March 31, 2014		Validus Re Segment (c)				AlphaCat Segment				Talbot Segment				Corporate & Eliminations (c)				Total
	Underwriting income
	Gross premiums written		$	666,163			$	84,347			$	290,695			$	(29,214	)		$	1,011,991
	Reinsurance premiums ceded		(129,817		)		(3,700		)		(90,605		)		29,214				(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 insurance related income (loss)		977				9,497				17				(2,454		)		8,037
	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		126,486				41,139				33,530				(32,611		)		168,544
	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)		$	127,064			$	14,356			$	33,660			$	(33,279	)		$	141,801
	Net realized (losses) gains on investments		2,446				1,225				69				—				3,740
	Change in net unrealized losses on investments		11,898				45,872				2,577				(4,654		)		55,693
Income from investment affiliate		5,348				—				—				—				5,348
Foreign exchange gains (losses)		(6,176		)		38				(150		)		(190		)		(6,478		)
Other income		5,793				—				—				—				5,793
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		80.5		%		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		$	5,730,615			$	1,582,014			$	2,975,533			$	94,788			$	10,382,950
(a)	Ratios are based on net premiums earned.
(b)	The general and administrative expense ratio includes share compensation expenses.
(c)	During the first quarter of 2015, certain intercompany reinsurance transactions were presented on a net basis for segmental reporting purposes. As a result, gross premiums written and reinsurance premiums ceded for the Validus Re segment and Corporate & Eliminations were reduced by $12,823 for the three months ended March 31, 2014 for comparative purposes. There was no impact to total gross premiums written and reinsurance premiums ceded on a consolidated basis.
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, 2015
		Gross Premiums Written
		Validus Re				AlphaCat				Talbot				Western World				Eliminations				Total				%
	United States	$	338,819			$	13,575			$	28,058			$	56,947			$	(1,494	)		$	435,905			38.9	%
	Worldwide excluding	34,994				5,833				34,942				—				(1,029		)		74,740				6.7	%
	United States (a)
	Australia and New Zealand	9,868				—				1,876				—				(155		)		11,589				1	%
	Europe	24,506				1,768				13,214				—				(844		)		38,644				3.5	%
	Latin America and Caribbean	8,878				—				22,692				—				(3,524		)		28,046				2.5	%
	Japan	1,384				—				754				—				(13		)		2,125				0.2	%
	Canada	2,187				194				1,698				—				(78		)		4,001				0.4	%
	Rest of the world (b)	18,726				—				23,006				—				(2,319		)		39,413				3.5	%
	Sub-total, non United States	100,543				7,795				98,182				—				(7,962		)		198,558				17.8	%
	Worldwide including	85,056				77,894				21,794				—				(11,854		)		172,890				15.4	%
	United States (a)
	Other location non-specific (c)	186,794				3,300				122,043				—				8				312,145				27.9	%
	Total	$	711,212			$	102,564			$	270,077			$	56,947			$	(21,302	)		$	1,119,498			100	%
		Three Months Ended March 31, 2014
		Gross Premiums Written
		Validus Re (d)				AlphaCat				Talbot				Eliminations (d)				Total				%
	United States	$	243,032			$	8,698			$	26,311			$	(2,320	)		$	275,721			27.3	%
	Worldwide excluding	58,523				7,678				37,182				(1,027		)		102,356				10	%
	United States (a)
	Australia and New Zealand	12,860				1,019				2,880				(326		)		16,433				1.6	%
	Europe	35,878				1,301				18,791				(1,767		)		54,203				5.4	%
	Latin America and Caribbean	14,337				—				31,239				(10,669		)		34,907				3.4	%
	Japan	167				—				538				(61		)		644				0.1	%
	Canada	2,547				216				3,145				(172		)		5,736				0.6	%
	Rest of the world (b)	18,795				—				18,404				(2,387		)		34,812				3.4	%
	Sub-total, non United States	143,107				10,214				112,179				(16,409		)		249,091				24.5	%
	Worldwide including	102,284				65,435				23,653				(11,418		)		179,954				17.8	%
	United States (a)
	Other location non-specific (c)	177,740				—				128,552				933				307,225				30.4	%
	Total	$	666,163			$	84,347			$	290,695			$	(29,214	)		$	1,011,991			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.
	(d)	During the first quarter of 2015, certain intercompany reinsurance transactions were presented on a net basis for segmental reporting purposes. As a result, gross premiums written for the Validus Re segment and Corporate & Eliminations were reduced by $12,823 for the three months ended March 31, 2014 for comparative purposes. There was no impact to total gross premiums written on a consolidated basis.

Condensed_consolidating_financ1

Condensed consolidating financial information (Tables)	3 Months Ended
	Mar. 31, 2015
Condensed Consolidating Financial Information [Abstract]
Condensed consolidating balance sheet
	Condensed Consolidating Balance Sheet	Validus Holdings, Ltd.			Validus Holdings			Other			Consolidating Adjustments (b)			Validus Holdings, Ltd.
	As at March 31, 2015	(Parent Guarantor)			(UK) plc			Validus Holdings, Ltd.						Consolidated
					(Subsidiary Issuer)			Subsidiaries
								(Non-guarantor Subsidiaries) (a)
	Assets
	Fixed maturities, at fair value	$	28,817		$	—		$	5,515,862		$	(60,200	)	$	5,484,479
	Short-term investments, at fair value	—			—			1,183,342			—			1,183,342
	Other investments, at fair value	—			—			950,992			(68,997		)	881,995
	Cash and cash equivalents	24,148			20			446,961			—			471,129
	Restricted cash	—			—			186,423			—			186,423
	Total investments and cash	52,965			20			8,283,580			(129,197		)	8,207,368
	Investment in affiliates	—			—			263,332			—			263,332
	Investment in subsidiaries on an equity basis	4,249,633			678,842			—			(4,928,475		)	—
	Premiums receivable	—			—			1,114,102			—			1,114,102
	Deferred acquisition costs	—			—			240,835			—			240,835
	Prepaid reinsurance premiums	—			—			192,694			—			192,694
	Securities lending collateral	—			—			5,337			—			5,337
	Loss reserves recoverable	—			—			375,882			—			375,882
	Paid losses recoverable	—			—			27,034			—			27,034
	Income taxes recoverable	—			—			10,597			—			10,597
	Deferred tax asset	—			—			30,847			—			30,847
	Receivable for investments sold	—			—			24,803			—			24,803
	Intangible assets	—			—			125,508			—			125,508
	Goodwill	—			—			195,897			—			195,897
	Accrued investment income	115			—			23,115			—			23,230
	Intercompany receivable	—			—			7,592			(7,592		)	—
	Other assets	2,758			—			214,226			—			216,984
	Total assets	$	4,305,471		$	678,862		$	11,135,381		$	(5,065,264	)	$	11,054,450
	Liabilities
	Reserve for losses and loss expenses	$	—		$	—		$	3,199,362		$	—		$	3,199,362
	Unearned premiums	—			—			1,452,179			—			1,452,179
	Reinsurance balances payable	—			—			101,426			—			101,426
	Securities lending payable	—			—			5,803			—			5,803
	Deferred tax liability	—			—			13,265			—			13,265
	Payable for investments purchased	—			—			123,556			—			123,556
	Accounts payable and accrued expenses	17,495			—			160,449			—			177,944
	Intercompany payable	7,534			58			—			(7,592		)	—
	Notes payable to operating affiliates	—			—			919,684			—			919,684
	Senior notes payable	247,333			—			—			—			247,333
	Debentures payable	350,000			—			247,761			(60,200		)	537,561
	Total liabilities	$	622,362		$	58		$	6,223,485		$	(67,792	)	$	6,778,113
	Redeemable noncontrolling interest	—			—			98,777			—			98,777
	Total shareholders' equity available to Validus	3,683,109			678,804			4,318,668			(4,997,472		)	3,683,109
	Noncontrolling interest	—			—			494,451			—			494,451
	Total liabilities, noncontrolling interests and shareholders' equity	$	4,305,471		$	678,862		$	11,135,381		$	(5,065,264	)	$	11,054,450
	(a)	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.
	(b)	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
	Condensed Consolidating Balance Sheet	Validus Holdings, Ltd.			Validus Holdings			Other			Consolidating Adjustments (b)			Validus Holdings, Ltd.
	As at December 31, 2014	(Parent Guarantor)			(UK) plc			Validus Holdings, Ltd.						Consolidated
					(Subsidiary Issuer)			Subsidiaries
								(Non-guarantor Subsidiaries) (a)
	Assets
	Fixed maturities, at fair value	$	—		$	—		$	5,592,931		$	(60,200	)	$	5,532,731
	Short-term investments, at fair value	—			—			1,051,074			—			$	1,051,074
	Other investments, at fair value	—			—			881,123			(68,112		)	$	813,011
	Cash and cash equivalents	29,798			81			547,361			—			$	577,240
	Restricted cash	—			—			173,003			—			173,003
	Total investments and cash	29,798			81			8,245,492			(128,312		)	8,147,059
	Investment in affiliates	—			—			261,483			—			261,483
	Investment in subsidiaries on an equity basis	4,140,770			656,738			—			(4,797,508		)	—
	Premiums receivable	—			—			707,647			—			707,647
	Deferred acquisition costs	—			—			161,295			—			161,295
	Prepaid reinsurance premiums	—			—			81,983			—			81,983
Securities lending collateral	—			—			470			—			470
Loss reserves recoverable	—			—			377,466			—			377,466
Paid losses recoverable	—			—			38,078			—			38,078
Deferred tax asset	—			—			23,821			—			23,821
Receivable for investments sold	—			—			18,318			—			18,318
Intangible assets	—			—			126,924			—			126,924
Goodwill	—			—			195,897			—			195,897
Accrued investment income	—			—			24,865			—			24,865
Intercompany receivable	41,078			—			20			(41,098		)	—
Other assets	3,239			—			161,394			—			164,633
Total assets	$	4,214,885		$	656,819		$	10,425,153		$	(4,966,918	)	$	10,329,939
Liabilities
Reserve for losses and loss expenses	$	—		$	—		$	3,234,394		$	—		$	3,234,394
Unearned premiums	—			—			990,564			—			990,564
Reinsurance balances payable	—			—			127,128			—			127,128
Securities lending payable	—			—			936			—			936
Deferred tax liability	—			—			5,541			—			5,541
Payable for investments purchased	—			—			68,574			—			68,574
Accounts payable and accrued expenses	29,621			96			288,528			—			318,245
Intercompany payable	—			20			41,078			(41,098		)	—
Notes payable to operating affiliates	—			—			671,465			—			671,465
Senior notes payable	247,306			—			—			—			247,306
Debentures payable	350,000			—			249,477			(60,200		)	539,277
Total liabilities	$	626,927		$	116		$	5,677,685		$	(101,298	)	$	6,203,430
Redeemable noncontrolling interest	—			—			79,956			—			79,956
Total shareholders' equity available to Validus	3,587,958			656,703			4,208,917			(4,865,620		)	3,587,958
Noncontrolling interest	—			—			458,595			—			458,595
Total liabilities, noncontrolling interests and shareholders' equity	$	4,214,885		$	656,819		$	10,425,153		$	(4,966,918	)	$	10,329,939
(a)	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.
(b)	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
Condensed consolidating statement of comprehensive income
	Condensed Consolidating	Validus Holdings, Ltd.			Validus Holdings			Other			Consolidating Adjustments (b)			Validus Holdings, Ltd.
	Statement of Comprehensive Income	(Parent Guarantor)			(UK) plc			Validus Holdings, Ltd.						Consolidated
	For the Three Months Ended March 31, 2015				(Subsidiary Issuer)			Subsidiaries
								(Non-guarantor Subsidiaries) (a)
	Revenues
	Net premiums earned	$	—		$	—		$	577,754		$	—		$	577,754
	Net investment income	57			—			31,969			(1,005		)	31,021
	Net realized gains on investments	—			—			4,169			—			4,169
	Change in net unrealized (losses) gains on investments	(73		)	—			73,162			(885		)	72,204
	Income from investment affiliate	—			—			2,776			—			2,776
	Other insurance related income and other income	—			—			19,623			(14,791		)	4,832
	Foreign exchange gains (losses)	510			—			(4,061		)	—			(3,551		)
	Total revenues	$	494		$	—		$	705,392		$	(16,681	)	$	689,205
	Expenses
	Losses and loss expenses	—			—			240,929			—			240,929
	Policy acquisition costs	—			—			98,636			—			98,636
	General and administrative expenses	17,543			2			82,276			(14,793		)	85,028
	Share compensation expenses	1,654			—			7,400			—			9,054
	Finance expenses	11,858			—			8,475			(481		)	19,852
	Total expenses	$	31,055		$	2		$	437,716		$	(15,274	)	$	453,499
	(Loss) income before taxes, income from operating affiliates, (income) attributable to operating affiliate investors and equity in net earnings of subsidiaries	(30,561		)	(2		)	267,676			(1,407		)	235,706
	Tax expense	—			—			(2,565		)	—			(2,565		)
	Income from operating affiliates	—			—			2,453			—			2,453
	(Income) attributable to operating affiliate investors	—			—			(23,206		)	—			(23,206		)
	Equity in net earnings of subsidiaries	203,972			20,195			—			(224,167		)	—
	Net income (loss)	$	173,411		$	20,193		$	244,358		$	(225,574	)	$	212,388
	Net (income) attributable to noncontrolling interest	—			—			(38,977		)	—			(38,977		)
	Net income available to Validus	$	173,411		$	20,193		$	205,381		$	(225,574	)	$	173,411
	Other comprehensive (loss)	(4,085		)	—			(3,284		)	3,284			(4,085		)
	Comprehensive income available to Validus	$	169,326		$	20,193		$	202,097		$	(222,290	)	$	169,326
	(a)	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.
	(b)	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
	Condensed Consolidating	Validus Holdings, Ltd.			Validus Holdings			Other			Consolidating Adjustments (b)			Validus Holdings, Ltd.
	Statement of Comprehensive Income	(Parent Guarantor)			(UK) plc			Validus Holdings, Ltd.						Consolidated
	For the Three Months Ended March 31, 2014				(Subsidiary Issuer)			Subsidiaries
								(Non-guarantor Subsidiaries) (a)
	Revenues
	Net premiums earned	$	—		$	—		$	482,957		$	—		$	482,957
	Net investment income	3			—			24,331			(972		)	23,362
	Net realized gains on investments	—			—			3,740			—			3,740
	Change in net unrealized gains on investments	—			—			51,465			4,228			55,693
	Income from investment affiliate	—			—			5,348			—			5,348
	Other insurance related income and other income	—			—			31,792			(17,962		)	13,830
	Foreign exchange losses	(168		)	—			(6,310		)	—			(6,478		)
	Total revenues	$	(165	)	$	—		$	593,323		$	(14,706	)	$	578,452
	Expenses
	Losses and loss expenses	—			—			162,671			—			162,671
	Policy acquisition costs	—			—			85,649			—			85,649
	General and administrative expenses	20,563			21			71,823			(17,962		)	74,445
	Share compensation expenses	1,308			—			5,839			—			7,147
	Finance expenses	11,823			—			4,557			(480		)	15,900
	Total expenses	$	33,694		$	21		$	330,539		$	(18,442	)	$	345,812
	(Loss) income before taxes, income from operating affiliates, (income) attributable to operating affiliate investors and equity in net earnings of subsidiaries	(33,859		)	(21		)	262,784			3,736			232,640
	Tax benefit	—			—			40			—			40
	Income from operating affiliates	—			—			4,927			—			4,927
	(Income) attributable to operating affiliate investors	—			—			(31,710		)	—			(31,710		)
	Equity in net earnings (losses) of subsidiaries	196,247			(748		)	—			(195,499		)	—
	Net income (loss)	$	162,388		$	(769	)	$	236,041		$	(191,763	)	$	205,897
	Net (income) attributable to noncontrolling interest	—			—			(43,509		)	—			(43,509		)
	Net income (loss) available (attributable) to Validus	$	162,388		$	(769	)	$	192,532		$	(191,763	)	$	162,388
	Other comprehensive income	462			—			462			(462		)	462
	Comprehensive income (loss) available (attributable) to Validus	$	162,850		$	(769	)	$	192,994		$	(192,225	)	$	162,850
	(a)	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.
(b)	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
Condensed consolidating statement of cash flows
	Condensed Consolidating Statement of Cash Flows	Validus Holdings, Ltd.			Validus Holdings			Other			Consolidating Adjustments (b)			Validus Holdings, Ltd.
	For the Three Months Ended March 31, 2015	(Parent Guarantor)			(UK) plc			Validus Holdings, Ltd.						Consolidated
					(Subsidiary Issuer)			Subsidiaries
								(Non-guarantor Subsidiaries) (a)
	Net cash provided by (used in) operating activities	$	5,572		$	(61	)	$	(234,052	)	$	—		$	(228,541	)
	Cash flows provided by (used in) investing activities
	Proceeds on sales of investments	—			—			1,190,559			—			1,190,559
	Proceeds on maturities of investments	—			—			93,732			—			93,732
	Purchases of fixed maturities	(28,902		)	—			(1,134,805		)	—			(1,163,707		)
	Purchases of short-term investments, net	—			—			(133,104		)	—			(133,104		)
	Purchases of other investments	—			—			(29,291		)	—			(29,291		)
	Increase in securities lending collateral	—			—			(4,867		)	—			(4,867		)
	Investment in operating affiliates	—			—			(1,070		)	—			(1,070		)
	Redemption from operating affiliates	—			—			24,150			—			24,150
	Investment in investment affiliates	—			—			(19,700		)	—			(19,700		)
	Increase in restricted cash	—			—			(13,420		)	—			(13,420		)
	Return of capital from subsidiaries	100,000			—			—			(100,000		)	—
	Net cash provided by (used in) investing activities	71,098			—			(27,816		)	(100,000		)	(56,718		)
	Cash flows provided by (used in) financing activities
	Proceeds on issuance of notes payable to operating affiliates	—			—			621,864			—			621,864
	Repayments on notes payable to operating affiliates	—			—			(365,883		)	—			(365,883		)
	Issuance of common shares, net	4,005			—			—			—			4,005
	Purchases of common shares under share repurchase program	(58,108		)	—			—			—			(58,108		)
	Dividends paid	(28,217		)	—			—			—			(28,217		)
	Increase in securities lending payable	—			—			4,867			—			4,867
	Third party investment in redeemable noncontrolling interest	—			—			15,700			—			15,700
	Return of capital to parent	—			—			(100,000		)	100,000			—
	Net cash (used in) provided by financing activities	(82,320		)	—			176,548			100,000			194,228
	Effect of foreign currency rate changes on cash and cash equivalents	—			—			(15,080		)	—			(15,080		)
	Net decrease in cash	(5,650		)	(61		)	(100,400		)	—			(106,111		)
	Cash and cash equivalents, beginning of year	29,798			81			547,361			—			577,240
	Cash and cash equivalents, end of year	$	24,148		$	20		$	446,961		$	—		$	471,129
	(a)	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.
	(b)	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
	Condensed Consolidating Statement of Cash Flows	Validus Holdings, Ltd.			Validus Holdings			Other			Consolidating Adjustments (b)			Validus Holdings, Ltd.
	For the Three Months Ended March 31, 2014	(Parent Guarantor)			(UK) plc			Validus Holdings, Ltd.						Consolidated
					(Subsidiary Issuer)			Subsidiaries
								(Non-guarantor Subsidiaries) (a)
	Net cash provided by (used in) operating activities	$	267,177		$	—		$	(311,604	)	$	—		$	(44,427	)
	Cash flows provided by (used in) investing activities
	Proceeds on sales of investments	—			—			984,356			—			984,356
	Proceeds on maturities of investments	—			—			124,716			—			124,716
	Purchases of fixed maturities	—			—			(782,290		)	—			(782,290		)
	Purchases of short-term investments, net	—			—			(107,437		)	—			(107,437		)
	Sales of other investments	—			—			7,059			—			7,059
	Increase in securities lending collateral	—			—			(1,485		)	—			(1,485		)
	Redemption from operating affiliates	—			—			43,366			—			43,366
	Decrease in restricted cash	—			—			91,274			—			91,274
	Net cash provided by investing activities	—			—			359,559			—			359,559
	Cash flows provided by (used in) financing activities
	Proceeds on issuance of notes payable to operating affiliates	—			—			154,028			—			154,028
	Repayments on notes payable to operating affiliates	—			—			(184,628		)	—			(184,628		)
	Issuance of common shares, net	2,030			—			—			—			2,030
	Purchases of common shares under share repurchase program	(197,339		)	—			—			—			(197,339		)
	Dividends paid	(29,330		)	—			—			—			(29,330		)
	Increase in securities lending payable	—			—			1,485			—			1,485
	Third party redemption of redeemable noncontrolling interest	—			—			(10,496		)	—			(10,496		)
	Net cash used in financing activities	(224,639		)	—			(39,611		)	—			(264,250		)
	Effect of foreign currency rate changes on cash and cash equivalents	—			—			4,890			—			4,890
	Net increase in cash	42,538			—			13,234			—			55,772
	Cash and cash equivalents, beginning of year	20,385			—			713,763			—			734,148
	Cash and cash equivalents, end of year	$	62,923		$	—		$	726,997		$	—		$	789,920
	(a)	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.
(b)	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.

Basis_of_preparation_and_conso1

Basis of preparation and consolidation (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Increase in net cash provided by investing activities
Reclassification adjustment	$94,768
Net increase in cash
Reclassification adjustment	$94,768

Investments_Gross_unrealized_g

Investments (Gross unrealized gains and losses on fixed maturities) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
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	$5,458,443		$5,534,494
Short-term investments, at amortized cost or cost	1,183,410	[1]	1,051,222	[1]
Other investments, at amortized cost or cost	908,405		879,176
Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest, amortized cost or cost	7,550,258		7,464,892
Catastrophe bonds, amortized cost or cost	-129,711		-75,822
Noncontrolling interest, amortized cost or cost	-525,330	[2]	-502,830	[2]
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest, amortized cost or cost	6,143,744		6,189,316
Fixed maturities, gross unrealized gains	44,784		24,357
Short term investments, gross unrealized gains	11	[1]	13	[1]
Other investments, gross unrealized gains	105,189		69,881
Gross unrealized gains	149,984		94,251
Catastrophe bonds, gross unrealized gains	-556		-768
Noncontrolling interest share of unrealized gains other investments	-79,346	[2]	-48,446	[2]
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest, unrealized gains	70,082		45,037
Fixed maturities, gross unrealized losses	-18,748		-26,120
Short term investments, gross unrealized losses	-79	[1]	-161	[1]
Other investments, gross unrealized losses	-131,599		-136,046
Gross unrealized losses	-150,426		-162,327
Catastrophe bonds, gross unrealized losses	3,050		926
Noncontrolling interest share of unrealized losses	116,603	[2]	120,782	[2]
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest, unrealized losses	-30,773		-40,619
Total fixed maturities	5,484,479		5,532,731
Short-term investments	1,183,342	[1]	1,051,074	[1]
Total other investments	881,995		813,011
Total investments, including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	7,549,816		7,396,816
Assets managed on behalf of operating affiliates (a)	-751,473	[1]	-696,924	[1]
Total catastrophe bonds	-127,217		-75,664
Noncontrolling interest	-488,073	[2]	-430,494	[2]
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	6,183,053		6,193,734
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	768,112		759,232
Fixed maturities, gross unrealized gains	3,867		1,755
Fixed maturities, gross unrealized losses	-278		-901
Total fixed maturities	771,701		760,086
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	244,372		279,493
Fixed maturities, gross unrealized gains	1,771		1,215
Fixed maturities, gross unrealized losses	-2,610		-1,980
Total fixed maturities	243,533		278,728
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	347,348		448,668
Fixed maturities, gross unrealized gains	3,749		1,780
Fixed maturities, gross unrealized losses	-254		-825
Total fixed maturities	350,843		449,623
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	522,951		520,685
Fixed maturities, gross unrealized gains	11,725		9,697
Fixed maturities, gross unrealized losses	-442		-1,151
Total fixed maturities	534,234		529,231
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	32,393		37,954
Fixed maturities, gross unrealized gains	360		369
Fixed maturities, gross unrealized losses	-645		-516
Total fixed maturities	32,108		37,807
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	1,436,724		1,500,963
Fixed maturities, gross unrealized gains	10,929		3,960
Fixed maturities, gross unrealized losses	-1,507		-5,217
Total fixed maturities	1,446,146		1,499,706
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	509,705		564,386
Fixed maturities, gross unrealized gains	4,827		2,765
Fixed maturities, gross unrealized losses	-3,951		-3,989
Total fixed maturities	510,581		563,162
Bank loans
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments
Fixed maturities, at amortized cost or cost	464,761		457,537
Fixed maturities, gross unrealized gains	1,417		200
Fixed maturities, gross unrealized losses	-4,838		-8,733
Total fixed maturities	461,340		449,004
Catastrophe bonds
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments
Fixed maturities, at amortized cost or cost	129,711		75,822
Fixed maturities, gross unrealized gains	556		768
Fixed maturities, gross unrealized losses	-3,050		-926
Total fixed maturities	127,217		75,664
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	702,298		647,422
Fixed maturities, gross unrealized gains	2,755		1,250
Fixed maturities, gross unrealized losses	-788		-1,190
Total fixed maturities	704,265		647,482
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	300,068		242,332
Fixed maturities, gross unrealized gains	2,828		598
Fixed maturities, gross unrealized losses	-385		-692
Total fixed maturities	302,511		242,238
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	1,915		2,570
Other investments, gross unrealized gains	76		125
Other investments, gross unrealized losses	-921		-920
Total other investments	1,070		1,775
Preferred stock
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments
Other investments, at amortized cost or cost	2,945		6,535
Other investments, gross unrealized gains	60		0
Other investments, gross unrealized losses	0		-201
Total other investments	3,005		6,334
Hedge funds
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments
Other investments, at amortized cost or cost	595,753	[2]	570,371	[2]
Other investments, gross unrealized gains	95,124	[2]	60,792	[2]
Other investments, gross unrealized losses	-129,559	[2]	-134,203	[2]
Total other investments	561,318	[2]	496,960	[2]
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	48,140		48,995
Other investments, gross unrealized gains	5,831		4,987
Other investments, gross unrealized losses	-1,119		-611
Total other investments	52,852		53,371
Investment funds
Amortized cost (or cost), gross unrealized gains and (losses) and estimated fair value of investments
Other investments, at amortized cost or cost	253,453		244,506
Other investments, gross unrealized gains	561		437
Other investments, gross unrealized losses	0		-111
Total other investments	254,014		244,832
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	3,537		3,540
Other investments, gross unrealized losses	0		0
Total other investments	$9,736		$9,739
[1]	Included in the short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.
[2]	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_Fixed_maturities_b

Investments (Fixed maturities by investment rating) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fixed Maturities
Estimated fair value	$5,484,479	$5,532,731
Percentage of total	100.00%	100.00%
Total investment grade fixed maturities
Fixed Maturities
Estimated fair value	4,791,444	4,933,764
Percentage of total	87.30%	89.20%
Total investment grade fixed maturities | AAA
Fixed Maturities
Estimated fair value	2,473,674	2,494,239
Percentage of total	45.10%	45.10%
Total investment grade fixed maturities | AA
Fixed Maturities
Estimated fair value	660,150	848,226
Percentage of total	12.00%	15.40%
Total investment grade fixed maturities | A
Fixed Maturities
Estimated fair value	1,087,156	1,086,091
Percentage of total	19.80%	19.60%
Total investment grade fixed maturities | BBB
Fixed Maturities
Estimated fair value	570,464	505,208
Percentage of total	10.40%	9.10%
Total non-investment grade fixed maturities
Fixed Maturities
Estimated fair value	693,035	598,967
Percentage of total	12.70%	10.80%
Total non-investment grade fixed maturities | BB
Fixed Maturities
Estimated fair value	307,561	362,972
Percentage of total	5.60%	6.60%
Total non-investment grade fixed maturities | B
Fixed Maturities
Estimated fair value	247,983	145,240
Percentage of total	4.50%	2.60%
Total non-investment grade fixed maturities | CCC
Fixed Maturities
Estimated fair value	4,365	12,733
Percentage of total	0.10%	0.20%
Total non-investment grade fixed maturities | CC
Fixed Maturities
Estimated fair value	3,286	3,926
Percentage of total	0.10%	0.10%
Total non-investment grade fixed maturities | C
Fixed Maturities
Estimated fair value	0	1,344
Percentage of total	0.00%	0.00%
Total non-investment grade fixed maturities | D/NR Rating
Fixed Maturities
Estimated fair value	$129,840	$72,752
Percentage of total	2.40%	1.30%

Investments_Maturity_profile_o

Investments (Maturity profile of fixed maturity investments) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Maturity profile
Amortized cost or cost	$5,458,443	$5,534,494
Estimated fair value	5,484,479	5,532,731
Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost or cost	3,900,733	4,086,101
Estimated fair value	3,911,363	4,075,973
Due in one year or less | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost or cost	291,651	312,843
Estimated fair value	292,276	313,248
Due after one year through five years | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost or cost	2,921,246	3,163,225
Estimated fair value	2,928,600	3,159,200
Due after five years through ten years | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost or cost	571,599	497,175
Estimated fair value	572,771	491,870
Due after ten years | Fixed maturities trading securities allocated to contractual maturity
Maturity profile
Amortized cost or cost	116,237	112,858
Estimated fair value	117,716	111,655
Asset backed and mortgaged backed securities | No single maturity date
Maturity profile
Amortized cost or cost	1,557,710	1,448,393
Estimated fair value	$1,573,116	$1,456,758

Investments_Components_of_net_

Investments (Components of net investment income) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Net investment income
Total gross investment income	$32,865	$25,256
Investment expenses	-1,844	-1,894
Net investment income	31,021	23,362
Fixed maturities and short term investments
Net investment income
Total gross investment income	29,239	23,297
Other investments
Net investment income
Total gross investment income	3,188	0
Restricted cash and cash and cash equivalents
Net investment income
Total gross investment income	435	1,957
Securities lending income
Net investment income
Total gross investment income	$3	$2

Investments_Realized_and_unrea

Investments (Realized and unrealized gains) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Fixed maturities, short-term and other investments and cash equivalents
Gross realized gains	$6,309		$5,296
Gross realized (losses)	-2,140		-1,556
Net realized gains (losses) on investments	4,169		3,740
Change in net unrealized gains on investments	72,204	[1]	55,693	[1]
Total net realized gains (losses) and change in net unrealized (losses) gains on investments including noncontrolling interest	76,373		59,433
Assets managed on behalf of operating affiliates	0		0
Catastrophe bonds	2,336		797
Noncontrolling interest	-35,079	[1]	-42,002	[1]
Total net realized and change in net unrealized gains on investments excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	$43,630		$18,228
PaCRe funds
Fixed maturities, short-term and other investments and cash equivalents
Noncontrolling Interest, Ownership Percentage by Parent	10.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	90.00%
[1]	Includes the change in net unrealized gains 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 loss (income) attributable to noncontrolling interest.

Investments_Investments_pledge

Investments (Investments pledged as collateral) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Financial Instruments Owned and Pledged as Collateral [Line Items]
Credit facility, commitment	$1,275,000		$1,605,000
Letters of credit issued and outstanding	560,306	[1]	561,684	[1]
Investments pledged as collateral	963,324		1,022,740
$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	268,907	[1]	276,455	[1]
Investments pledged as collateral	400,774		395,750
Secured bi-lateral letter of credit facility
Financial Instruments Owned and Pledged as Collateral [Line Items]
Credit facility, commitment	30,000		200,000
Letters of credit issued and outstanding	14,747	[1]	15,649	[1]
Investments pledged as collateral	27,019		35,645
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	[1]	25,000	[1]
Investments pledged as collateral	31,221		31,048
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	39	[1]	294	[1]
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		30,000		24,800
Letters of credit issued and outstanding	30,000	[1]	30,000	[1]
Investments pledged as collateral	30,097		30,078
IPC bi-lateral facility
Financial Instruments Owned and Pledged as Collateral [Line Items]
Credit facility, commitment	25,000		40,000
Letters of credit issued and outstanding	12,543	[1]	15,897	[1]
Investments pledged as collateral	100,549		99,437
Flagstone bi-lateral facility
Financial Instruments Owned and Pledged as Collateral [Line Items]
Credit facility, commitment	230,000		375,000
Letters of credit issued and outstanding	209,070	[1]	198,389	[1]
Investments pledged as collateral	$373,664		$430,782
[1]	Indicates utilization of commitment amount, not necessarily drawn borrowings.

Investments_Narrative_Details

Investments (Narrative) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cash, cash equivalents and investments pledged as collateral	$3,267,654	$3,150,295
Investments held in trust	$3,208,722	$3,122,074
AlphaCat ILS Funds
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments Number Of Funds	1
PaCRe funds
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Investments Number Of Funds	5
Noncontrolling Interest, Ownership Percentage by Parent	10.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	90.00%

Fair_value_measurements_Fair_v

Fair value measurements (Fair value hierarchy) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	$5,484,479		$5,532,731
Short-term investments, at fair value	1,183,342	[1]	1,051,074	[1]
Other investments, at fair value	881,995		813,011
Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	7,549,816		7,396,816
Assets managed on behalf of operating affiliates (a)	-751,473	[1]	-696,924	[1]
Catastrophe bonds	-127,217		-75,664
Noncontrolling interest	-488,073	[2]	-430,494	[2]
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	6,183,053		6,193,734
U.S. government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	771,701		760,086
Non-US government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	243,533		278,728
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	350,843		449,623
Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	534,234		529,231
Non-Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	32,108		37,807
U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	1,446,146		1,499,706
Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	510,581		563,162
Bank loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	461,340		449,004
Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	127,217		75,664
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	704,265		647,482
Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	302,511		242,238
Fund of hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	1,070		1,775
Preferred stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	3,005		6,334
Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	561,318	[2]	496,960	[2]
Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	52,852		53,371
Investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	254,014		244,832
Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	9,736		9,739
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	5,484,479		5,532,731
Short-term investments, at fair value	1,183,342	[1]	1,051,074	[1]
Other investments, at fair value	881,995		813,011
Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	7,549,816		7,396,816
Assets managed on behalf of operating affiliates (a)	-751,473	[1]	-696,924	[1]
Catastrophe bonds	-127,217		-75,664
Noncontrolling interest	-488,073	[2]	-430,494	[2]
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	6,183,053		6,193,734
Recurring | U.S. government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	771,701		760,086
Recurring | Non-US government and government agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	243,533		278,728
Recurring | 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	350,843		449,623
Recurring | Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	534,234		529,231
Recurring | Non-Agency residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	32,108		37,807
Recurring | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	1,446,146		1,499,706
Recurring | Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	510,581		563,162
Recurring | Bank loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	461,340		449,004
Recurring | Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	127,217		75,664
Recurring | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	704,265		647,482
Recurring | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	302,511		242,238
Recurring | Fund of hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	1,070		1,775
Recurring | Preferred stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	3,005		6,334
Recurring | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	561,318	[2]	496,960	[2]
Recurring | Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	52,852		53,371
Recurring | Investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	254,014		244,832
Recurring | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	9,736		9,739
Recurring | 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	1,084,139	[1]	942,716	[1]
Other investments, at fair value	0		0
Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	1,084,139		942,716
Assets managed on behalf of operating affiliates (a)	-751,473	[1]	-696,924	[1]
Catastrophe bonds	0		0
Noncontrolling interest	0	[2]	0	[2]
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	332,666		245,792
Recurring | 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
Recurring | 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
Recurring | 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
Recurring | 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
Recurring | 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
Recurring | 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
Recurring | 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
Recurring | Level 1 | Bank loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0		0
Recurring | Level 1 | Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0		0
Recurring | 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
Recurring | 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		0
Recurring | 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
Recurring | Level 1 | Preferred stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	0		0
Recurring | Level 1 | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	0	[2]	0	[2]
Recurring | 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
Recurring | Level 1 | Investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	0		0
Recurring | Level 1 | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	0		0
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	5,401,760		5,494,983
Short-term investments, at fair value	92,389	[1]	108,358	[1]
Other investments, at fair value	103,872		156,118
Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	5,598,021		5,759,459
Assets managed on behalf of operating affiliates (a)	0	[1]	0	[1]
Catastrophe bonds	-124,217		-70,664
Noncontrolling interest	0	[2]	0	[2]
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	5,473,804		5,688,795
Recurring | 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	771,701		760,086
Recurring | 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	243,533		278,728
Recurring | 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	350,843		449,623
Recurring | 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	534,234		529,231
Recurring | 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	32,108		37,807
Recurring | Level 2 | U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	1,446,146		1,499,706
Recurring | Level 2 | Non-U.S. corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	510,581		563,162
Recurring | Level 2 | Bank loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	381,621		416,256
Recurring | Level 2 | Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	124,217		70,664
Recurring | Level 2 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	704,265		647,482
Recurring | Level 2 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	302,511		242,238
Recurring | 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
Recurring | Level 2 | Preferred stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	3,005		6,334
Recurring | Level 2 | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	0	[2]	0	[2]
Recurring | 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
Recurring | Level 2 | Investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	91,131		140,045
Recurring | Level 2 | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	9,736		9,739
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	82,719		37,748
Short-term investments, at fair value	6,814	[1]	0	[1]
Other investments, at fair value	778,123		656,893
Total investments including assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	867,656		694,641
Assets managed on behalf of operating affiliates (a)	0	[1]	0	[1]
Catastrophe bonds	-3,000		-5,000		0
Noncontrolling interest	-488,073	[2],[3]	-430,494	[2]	-531,403	[3]
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	376,583		259,147
Recurring | 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
Recurring | 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
Recurring | 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
Recurring | 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
Recurring | 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
Recurring | 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
Recurring | 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
Recurring | Level 3 | Bank loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	79,719		32,748
Recurring | Level 3 | Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	3,000		5,000
Recurring | 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
Recurring | 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		0
Recurring | Level 3 | Fund of hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	1,070		1,775
Recurring | Level 3 | Preferred stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	0		0
Recurring | Level 3 | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	561,318	[2]	496,960	[2]
Recurring | Level 3 | Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	52,852		53,371
Recurring | Level 3 | Investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments, at fair value	162,883		104,787
Recurring | 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 short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.
[2]	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.
[3]	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.

Fair_value_measurements_Level_

Fair value measurements (Level 3 rollforward) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Reconciliation of beginning and ending balances for all investments measured at fair value on recurring basis
Catastrophe bonds	($127,217)				($75,664)
Noncontrolling interest	-488,073	[1]			-430,494	[1]
Recurring
Reconciliation of beginning and ending balances for all investments measured at fair value on recurring basis
Catastrophe bonds	-127,217				-75,664
Noncontrolling interest	-488,073	[1]			-430,494	[1]
Level 3 | Recurring
Reconciliation of beginning and ending balances for all investments measured at fair value on recurring basis
Level 3 investments - beginning of period	694,641		576,871
Purchases	145,789		0
Sales	-7,602		-3,589
Settlements	-3,995		0
Realized gains	-11		10
Unrealized losses	38,834		49,326
Transfers	0		6,703
Level 3 investments - end of period	867,656		629,321
Catastrophe bonds	-3,000		0		-5,000
Noncontrolling interest	-488,073	[1],[2]	-531,403	[2]	-430,494	[1]
Level 3 investments - end of period excluding catastrophe bonds and noncontrolling interest	$376,583		$97,918
PaCRe funds
Reconciliation of beginning and ending balances for all investments measured at fair value on recurring basis
Noncontrolling Interest, Ownership Percentage by Parent	10.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	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]	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.

Fair_value_measurements_Narrat

Fair value measurements (Narrative) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	6,183,053		$6,193,734
Other investments, at fair value	881,995		813,011
AlphaCat ILS Funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other Investments Number Of Funds	1
Mutual funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	9,736		9,739
Hedge fund side pocket
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment Time Lag Reporting	1 month
Hedge funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	561,318	[1]	496,960	[1]
Fund of hedge funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	1,070		1,775
Investments assumed in Flagstone acquisition
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
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%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	90.00%
Other Investments Number Of Funds	5
Investment funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	254,014		244,832
Private equity investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	52,852		53,371
Minimum | Hedge funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment Time Lag Reporting	1 month
Minimum | Private equity investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment Time Lag Reporting	3 months
Maximum | Hedge funds
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
Level 2 | Mutual funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other Investments Number Of Funds	2
Level 2 | Investment funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other Investments Number Of Funds	1
Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment Time Lag Reporting	1 month
Other Investments Number Of Funds	1
Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	6,183,053		6,193,734
Other investments, at fair value	881,995		813,011
Recurring | Mutual funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	9,736		9,739
Recurring | Hedge funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	561,318	[1]	496,960	[1]
Recurring | Fund of hedge funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	1,070		1,775
Recurring | Investment funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	254,014		244,832
Recurring | Private equity investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	52,852		53,371
Recurring | Level 2
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	5,473,804		5,688,795
Other investments, at fair value	103,872		156,118
Recurring | Level 2 | Mutual funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	9,736		9,739
Recurring | Level 2 | Hedge funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	0	[1]	0	[1]
Recurring | Level 2 | Fund of hedge funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	0		0
Recurring | Level 2 | Investment funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	91,131		140,045
Recurring | Level 2 | Private equity investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	0		0
Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Percentage Of Fair Value Assets Measured On Recurring Basis	6.10%		4.20%
Total investments, excluding assets managed on behalf of operating affiliates, catastrophe bonds and noncontrolling interest	376,583		259,147
Other investments, at fair value	778,123		656,893
Recurring | Level 3 | Mutual funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	0		0
Recurring | Level 3 | Hedge funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	561,318	[1]	496,960	[1]
Recurring | Level 3 | Fund of hedge funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	1,070		1,775
Recurring | Level 3 | Investment funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	162,883		104,787
Recurring | Level 3 | Private equity investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other investments, at fair value	52,852		$53,371
[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, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	$263,332	$261,483
Investment affiliate
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	85,982	63,506
Operating affiliates
Schedule of Equity Method Investments [Line Items]
Investments in affiliates	$177,350	$197,977

Investments_in_affiliates_Inve

Investments in affiliates (Investment affiliate rollforward) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Schedule of Equity Method Investments [Line Items]
Income from investment affiliate	$2,776	$5,348
Investment affiliate
Schedule of Equity Method Investments [Line Items]
Balance, beginning of period	63,506	34,500
Capital contributions	19,700	0
Income from investment affiliate	2,776	5,348
Balance, end of period	$85,982	$39,848

Investments_in_affiliates_Inve1

Investments in affiliates (Investment affiliate details) (Details) (Investment affiliate, USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Equity Method Investments [Line Items]
Investment at cost	$70,701
Carrying value	85,982	63,506	39,848	34,500
Aquiline Financial Services Fund II LP
Schedule of Equity Method Investments [Line Items]
Investment at cost	56,563	51,001
Voting ownership %	0.00%	0.00%
Equity ownership %	8.10%	8.10%
Carrying value	71,844	63,506
Aquiline Financial Services Fund III LP
Schedule of Equity Method Investments [Line Items]
Investment at cost	14,138
Voting ownership %	0.00%
Equity ownership %	13.70%
Carrying value	$14,138

Investments_in_affiliates_Oper

Investments in affiliates (Operating affiliates rollforward) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Activity in non-consolidated affiliate balances for the period:
Income from operating affiliates	$2,453		$4,927
Operating affiliates
Activity in non-consolidated affiliate balances for the period:
Balance, beginning of period	197,977		106,743
Purchase of shares	1,070
Return of investment	-24,150		-43,366
Fair value of retained interest on deconsolidation of AlphaCat ILS fund			113,455
Income from operating affiliates	2,453		4,927
Balance, end of period	177,350		181,759
Operating affiliates | AlphaCat Re 2011
Activity in non-consolidated affiliate balances for the period:
Balance, beginning of period	4,606		9,809
Purchase of shares	0
Return of investment	0		-5,825
Income from operating affiliates	-10		193
Balance, end of period	4,596		4,177
Operating affiliates | AlphaCat Re 2012
Activity in non-consolidated affiliate balances for the period:
Balance, beginning of period	735		1,313
Purchase of shares	0
Return of investment	0		0
Income from operating affiliates	-25		-36
Balance, end of period	710		1,277
Operating affiliates | AlphaCat 2013
Activity in non-consolidated affiliate balances for the period:
Balance, beginning of period	1,068		51,744
Purchase of shares	0
Return of investment	0		-37,541
Income from operating affiliates	-14		1,475
Balance, end of period	1,054		15,678
Operating affiliates | AlphaCat 2014
Activity in non-consolidated affiliate balances for the period:
Balance, beginning of period	28,085		21,982
Purchase of shares	0
Return of investment	-24,150		0
Income from operating affiliates	-100		1,611
Balance, end of period	3,835		23,593
Operating affiliates | AlphaCat 2015
Activity in non-consolidated affiliate balances for the period:
Balance, beginning of period	25,600
Purchase of shares	0
Return of investment	0
Income from operating affiliates	1,316
Balance, end of period	26,916
Operating affiliates | AlphaCat ILS Funds
Activity in non-consolidated affiliate balances for the period:
Balance, beginning of period	137,883	[1]	21,895
Purchase of shares	1,070
Return of investment	0		0
Fair value of retained interest on deconsolidation of AlphaCat ILS fund			113,455
Income from operating affiliates	1,286		1,684
Balance, end of period	$140,239	[2]	$137,034
[1]	Equity ownership in the funds was 7.9%, 39.7% and 9.1%, respectively as at December 31, 2014
[2]	Includes the change in net unrealized gains 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 loss (income) attributable to noncontrolling interest.

Investments_in_affiliates_Oper1

Investments in affiliates (Operating affiliates details) (Details) (Operating affiliates, USD $)	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investment:
Investment at cost	$169,956		$187,100
Carrying value	177,350		197,977		181,759	106,743
AlphaCat Re 2011
Investment:
Investment at cost	4,596		4,606
Voting ownership %	43.70%		43.70%
Equity ownership %	22.30%		22.30%
Carrying value	4,596		4,606		4,177	9,809
AlphaCat Re 2012
Investment:
Investment at cost	710		735
Voting ownership %	49.00%		49.00%
Equity ownership %	37.90%		37.90%
Carrying value	710		735		1,277	1,313
AlphaCat 2013
Investment:
Investment at cost	1,054		1,068
Voting ownership %	40.90%		40.90%
Equity ownership %	19.70%		19.70%
Carrying value	1,054		1,068		15,678	51,744
AlphaCat 2014
Investment:
Investment at cost	3,835		22,000
Voting ownership %	42.30%		42.30%
Equity ownership %	19.60%		19.60%
Carrying value	3,835		28,085		23,593	21,982
AlphaCat 2015
Investment:
Investment at cost	25,600		25,600
Voting ownership %	40.00%		40.00%
Equity ownership %	20.00%		20.00%
Carrying value	26,916		25,600
AlphaCat ILS Funds
Investment:
Investment at cost	134,161	[1]	133,091	[2]
Carrying value	$140,239	[1]	$137,883	[2]	$137,034	$21,895
[1]	Includes the change in net unrealized gains 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 loss (income) attributable to noncontrolling interest.
[2]	Equity ownership in the funds was 7.9%, 39.7% and 9.1%, respectively as at December 31, 2014

Investments_in_affiliates_Note

Investments in affiliates (Notes payable to operating affiliates) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Notes payable to operating affiliates, beginning of period			$671,465
Notes payable to operating affiliates, end of period	919,684		671,465
Variable interest entity, not primary beneficiary
Schedule of Equity Method Investments [Line Items]
Notes payable to operating affiliates, beginning of period	671,465	439,272
Issuance of notes payable to operating affiliates	621,864	334,444
Notes payable to operating affiliates recognized on deconsolidation of AlphaCat ILS fund		178,837
Redemption of notes payable to operating affiliates	-365,883	-391,115
Foreign exchange (gain) loss	-7,762	-65
Notes payable to operating affiliates, end of period	919,684	561,373
Variable interest entity, not primary beneficiary | AlphaCat 2013
Schedule of Equity Method Investments [Line Items]
Notes payable to operating affiliates, beginning of period	0	223,809
Issuance of notes payable to operating affiliates	0	0
Notes payable to operating affiliates recognized on deconsolidation of AlphaCat ILS fund		0
Redemption of notes payable to operating affiliates	0	-175,349
Foreign exchange (gain) loss	0	-297
Notes payable to operating affiliates, end of period	0	48,163
Variable interest entity, not primary beneficiary | AlphaCat 2014
Schedule of Equity Method Investments [Line Items]
Notes payable to operating affiliates, beginning of period	157,384	0
Issuance of notes payable to operating affiliates	0	149,707
Notes payable to operating affiliates recognized on deconsolidation of AlphaCat ILS fund		0
Redemption of notes payable to operating affiliates	-148,893	0
Foreign exchange (gain) loss	-310	109
Notes payable to operating affiliates, end of period	8,181	149,816
Variable interest entity, not primary beneficiary | AlphaCat 2015
Schedule of Equity Method Investments [Line Items]
Notes payable to operating affiliates, beginning of period	0
Issuance of notes payable to operating affiliates	137,540
Redemption of notes payable to operating affiliates	0
Foreign exchange (gain) loss	-246
Notes payable to operating affiliates, end of period	137,294
Variable interest entity, not primary beneficiary | AlphaCat ILS Funds
Schedule of Equity Method Investments [Line Items]
Notes payable to operating affiliates, beginning of period	514,081	215,463
Issuance of notes payable to operating affiliates	484,324	184,737
Notes payable to operating affiliates recognized on deconsolidation of AlphaCat ILS fund		178,837
Redemption of notes payable to operating affiliates	-216,990	-215,766
Foreign exchange (gain) loss	-7,206	123
Notes payable to operating affiliates, end of period	$774,209	$363,394

Investments_in_affiliates_Inco

Investments in affiliates (Income attributable to operating affiliates) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Schedule of Equity Method Investments [Line Items]
(Income) attributable to operating affiliate investors	($23,206)	($31,710)
Variable interest entity, not primary beneficiary | AlphaCat 2013
Schedule of Equity Method Investments [Line Items]
(Income) attributable to operating affiliate investors	1	-10,476
Variable interest entity, not primary beneficiary | AlphaCat 2014
Schedule of Equity Method Investments [Line Items]
(Income) attributable to operating affiliate investors	-156	-10,789
Variable interest entity, not primary beneficiary | AlphaCat 2015
Schedule of Equity Method Investments [Line Items]
(Income) attributable to operating affiliate investors	-8,773	0
Variable interest entity, not primary beneficiary | AlphaCat ILS Funds
Schedule of Equity Method Investments [Line Items]
(Income) attributable to operating affiliate investors	($14,278)	($10,445)

Investments_in_affiliates_Narr

Investments in affiliates (Narrative) (Details) (USD $)	3 Months Ended	0 Months Ended				3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Oct. 02, 2014	Dec. 20, 2011	Nov. 07, 2014	Dec. 29, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Variable Funding Notes, Typical Minimum Duration	12 months
Aquiline Financial Services Fund II LP
Schedule of Equity Method Investments [Line Items]
Percentage of Assignor's interest assumed			100.00%
Total capital commitment		$10,000	$50,000
Investment Time Lag Reporting	3 months
Aquiline Financial Services Fund III LP
Schedule of Equity Method Investments [Line Items]
Total capital commitment				100,000
Investment Time Lag Reporting	3 months
AlphaCat ILS Funds
Schedule of Equity Method Investments [Line Items]
Total capital commitment					20,000
Fund D [Member]
Schedule of Equity Method Investments [Line Items]
Third party subscriptions							35,000
Operating affiliates
Schedule of Equity Method Investments [Line Items]
Fair value of retained interest on deconsolidation of AlphaCat ILS fund						113,455
Notes Payable Of Operating Affiliates Portion Due to Company	152,891							148,264
Income Attributable To Operating Affiliates Portion Due to Company	3,444					6,472
Operating affiliates | AlphaCat ILS Funds
Schedule of Equity Method Investments [Line Items]
Fair value of retained interest on deconsolidation of AlphaCat ILS fund						113,455
Deconsolidation, Gain (Loss), Amount						1,372
As investor in third party economic interests
Schedule of Equity Method Investments [Line Items]
Notes Payable Of Operating Affiliates Portion Due to Company	766,793							523,201
Income Attributable To Operating Affiliates Portion Due to Company	19,762					$25,238
Variable Interest Entity, Primary Beneficiary [Member] | BetaCat ILS Funds [Member]
Schedule of Equity Method Investments [Line Items]
Number of Consolidated Funds	1
Variable Interest Entity, Primary Beneficiary [Member] | Fund D [Member]
Schedule of Equity Method Investments [Line Items]
Number of Consolidated Funds							1
Variable Interest Entity, Primary Beneficiary [Member] | Operating affiliates | FundA [Member]
Schedule of Equity Method Investments [Line Items]
Equity ownership %	7.60%							7.90%
Variable Interest Entity, Primary Beneficiary [Member] | Operating affiliates | Fund B [Member]
Schedule of Equity Method Investments [Line Items]
Equity ownership %	25.20%							39.70%
Variable Interest Entity, Primary Beneficiary [Member] | Operating affiliates | Fund C [Member]
Schedule of Equity Method Investments [Line Items]
Equity ownership %	9.10%							9.10%

Noncontrolling_interest_Detail

Noncontrolling interest (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Redeemable noncontrolling interest and noncontrolling interest, rollforward:
Redeemable noncontrolling interest and noncontrolling interest, beginning of period	$538,551	$584,169
Issuance of shares	15,700
Income (loss) attributable to noncontrolling interest	38,977	43,509
Adjustment to noncontrolling interest as a result of deconsolidation		-78,354
Redeemable noncontrolling interest and noncontrolling interest, end of period	593,228	549,324
PaCRe funds
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	10.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	90.00%
Other Investments Number Of Funds	5
AlphaCat ILS Funds
Noncontrolling Interest [Line Items]
Other Investments Number Of Funds	1
Redeemable noncontrolling interest
Redeemable noncontrolling interest and noncontrolling interest, rollforward:
Redeemable noncontrolling interest and noncontrolling interest, beginning of period	79,956	86,512
Issuance of shares	15,700
Income (loss) attributable to noncontrolling interest	3,121	232
Adjustment to noncontrolling interest as a result of deconsolidation		-78,354
Redeemable noncontrolling interest and noncontrolling interest, end of period	98,777	8,390
Noncontrolling interest
Redeemable noncontrolling interest and noncontrolling interest, rollforward:
Redeemable noncontrolling interest and noncontrolling interest, beginning of period	458,595	497,657
Issuance of shares	0
Income (loss) attributable to noncontrolling interest	35,856	43,277
Redeemable noncontrolling interest and noncontrolling interest, end of period	$494,451	$540,934

Derivative_instruments_Amount_

Derivative instruments (Amount and balance sheet location) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Derivative, Number of Instruments Held	1
Not designated as hedging instruments | Foreign exchange contracts
Summary of amount of derivatives designated as hedging instruments
Net Notional Exposure	$22,039		$26,755
Not designated as hedging instruments | Foreign exchange contracts | Other assets
Summary of amount of derivatives designated as hedging instruments
Asset Derivative at Fair Value	0	[1]	1,685	[1]
Not 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	225	[1]	0	[1]
Designated as hedging instruments | Foreign exchange contracts
Summary of amount of derivatives designated as hedging instruments
Net Notional Exposure	202,779		189,026
Designated as hedging instruments | Foreign exchange contracts | Other assets
Summary of amount of derivatives designated as hedging instruments
Asset Derivative at Fair Value	584	[2]	401	[2]
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	9,384	[2]	3,136	[2]
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	21	[2]	25	[2]
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	$1,915	[2]	$1,169	[2]
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. The net impact on earnings during the three months ended March 31, 2015, recognized in income within other income, relating to the foreign currency forward contract that was not designated as a hedging instrument was $1 (2014: $nil).
[2]	Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses respectively on the Consolidated Balance Sheets.

Derivative_instruments_Amount_1

Derivative instruments (Amount included in statement of operations) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Not designated as hedging instruments | Foreign exchange contracts | Other Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Asset Derivative at Fair Value	$0		$0
Designated as hedging instruments | 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	-10,113	3,303
Amount of (loss) gain on hedged item recognized in income attributable to risk being hedged	10,113	-3,303
Amount of gain (loss) recognized in income on derivative (ineffective portion)	0	0
Designated as hedging instruments | Cash flow hedge | Interest rate swap contracts
Derivative instruments designated as a cash flow hedge
Amount of ineffective portion excluded from effectiveness testing	-801	0
Designated as hedging instruments | 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	4,040	3,208
Designated as hedging instruments | 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	($3,239)	($3,208)

Reserve_for_losses_and_loss_ex2

Reserve for losses and loss expenses (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Reserve for paid losses and unpaid loss expenses
Reserve for losses and loss expenses, beginning of period	$3,234,394	$3,030,399
Losses and loss expenses recoverable, beginning of period	-377,466	-370,154
Net reserves for losses and loss expenses, beginning of period	2,856,928	2,660,245
Increase (decrease) in net losses and loss expenses incurred in respect of losses occurring in:
Current year	324,488	202,086
Prior years	-83,559	-39,415
Total incurred losses and loss expenses	240,929	162,671
Less net losses and loss expenses paid in respect of losses occurring in:
Current year	-13,100	-7,967
Prior years	-236,003	-250,115
Total net paid losses	-249,103	-258,082
Foreign exchange (gain) loss	-25,274	11,818
Net reserve for losses and loss expenses, end of period	2,823,480	2,576,652
Losses and loss expenses recoverable, end of period	375,882	348,407
Reserve for losses and loss expenses, end of period	3,199,362	2,925,059
Components of incurred losses and loss expenses
Gross losses and loss expenses	264,796	181,975
Reinsurance recoverable	-23,867	-19,304
Net incurred losses and loss expenses	$240,929	$162,671

Reinsurance_Details

Reinsurance (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$402,916	$415,544
Percentage of reinsurance recoverables	100.00%	100.00%
Reinsurance (Textuals) [Abstract]
Incurred but not reported recoverable	241,983	231,129
Provision for uncollectible reinsurance relating to losses recoverable	4,834	4,755
A- or better
Ceded Credit Risk [Line Items]
Percentage of reinsurance recoverables	98.40%	98.00%
Top 10 reinsurers
Ceded Credit Risk [Line Items]
Reinsurance recoverable	317,056	312,205
Percentage of reinsurance recoverables	78.70%	75.10%
Top 10 reinsurers | Swiss Re | AA-
Ceded Credit Risk [Line Items]
Reinsurance recoverable	79,535	70,848
Percentage of reinsurance recoverables	19.70%	17.00%
Top 10 reinsurers | Lloyds Syndicates | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable	61,406	62,318
Percentage of reinsurance recoverables	15.20%	15.00%
Top 10 reinsurers | Everest Re | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable	46,105	51,425
Percentage of reinsurance recoverables	11.40%	12.40%
Top 10 reinsurers | Hannover Re | AA-
Ceded Credit Risk [Line Items]
Reinsurance recoverable	41,330	40,927
Percentage of reinsurance recoverables	10.30%	9.80%
Top 10 reinsurers | Fully Collateralized | NR
Ceded Credit Risk [Line Items]
Reinsurance recoverable	29,979	23,315
Percentage of reinsurance recoverables	7.40%	5.60%
Top 10 reinsurers | Munich Re | AA-
Ceded Credit Risk [Line Items]
Reinsurance recoverable	21,632	19,384
Percentage of reinsurance recoverables	5.40%	4.70%
Top 10 reinsurers | Transatlantic Re | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable	11,605	12,418
Percentage of reinsurance recoverables	2.90%	3.00%
Top 10 reinsurers | XL Re | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable	9,897	11,114
Percentage of reinsurance recoverables	2.50%	2.70%
Top 10 reinsurers | Berkshire Hathaway Homestate | AA plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable		10,372
Percentage of reinsurance recoverables		2.50%
Top 10 reinsurers | Merrimack Mutual Fire Insurance | A plus
Ceded Credit Risk [Line Items]
Reinsurance recoverable	8,076	10,084
Percentage of reinsurance recoverables	2.00%	2.40%
Top 10 reinsurers | Hamilton Re | A-
Ceded Credit Risk [Line Items]
Reinsurance recoverable	7,491
Percentage of reinsurance recoverables	1.90%
Other reinsurers' balances greater than $1 million
Ceded Credit Risk [Line Items]
Reinsurance recoverable	79,034	94,247
Percentage of reinsurance recoverables	19.60%	22.70%
Other reinsurers' balances less than $1 million
Ceded Credit Risk [Line Items]
Reinsurance recoverable	$6,826	$9,092
Percentage of reinsurance recoverables	1.70%	2.20%

Share_capital_Details

Share capital (Details) (USD $)	0 Months Ended	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Feb. 03, 2015	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
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
Common share repurchase authorization	$750,000
Share repurchase program, cumulative shares repurchased		71,475,993
Shares repurchased, cumulative	2,274,401	2,289,409
Remaining share repurchase authorization amount		$734,992
Number of warrants exercised during period		798,575	0
Cash dividends declared per share		$0.32	$0.30
Summary of common shares issued and outstanding
Common shares issued, beginning balance		155,554,224	154,488,497
Options exercised (in shares)		704,974	90,019
Direct issuance of common stock (in shares)		324	359
Common shares issued, ending balance		156,749,783	154,597,094
Treasury shares, ending balance		-73,114,868	-63,810,857
Common shares outstanding, ending balance		83,634,915	90,786,237	83,869,845
Common shares
Share repurchases
Cash dividends declared per share		$0.32	$0.30
Summary of common shares issued and outstanding
Warrants exercised (in shares)		473,817
Common share equivalents
Share repurchases
Cash dividends declared per share		$0.32
Warrants
Share repurchases
Number of outstanding warrants		4,375,538		5,174,114
Restricted share awards
Summary of common shares issued and outstanding
Vested, net of shares withheld		14,447	18,219
Restricted share units
Summary of common shares issued and outstanding
Vested, net of shares withheld		1,997

Stock_plans_Options_activity_D

Stock plans (Options activity) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Options activities:
Options outstanding, beginning balance (in shares)	1,160,057	1,572,713
Options exercised during period (in shares)	-1,017,165	-90,019
Options outstanding, ending balance (in shares)	142,892	1,482,694
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, beginning balance (in dollars per share)	$7.12	$6.66
Weighted average grant date fair value, options exercised (in dollars per share)	$7.36	$4.25
Weighted average grant date fair value, ending balance (in dollars per share)	$5.45	$6.81
Weighted Average Grant Date Exercise Price
Weighted average grant date exercise price, beginning balance (in dollars per share)	$17.74	$18.88
Weighted average grant date exercise price, options exercised (in dollars per share)	$16.55	$25.46
Weighted average grant date exercise price, ending balance (in dollars per share)	$26.24	$18.48

Stock_plans_Other_awards_activ

Stock plans (Other awards activity) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Restricted share awards
Activities
Beginning balance (in shares)	2,858,711	2,684,745
Granted (in shares)		17,533
Vested (in shares)	-19,682	-27,353
Forfeited (in shares)	-2,410	-23,094
Ending balance (in shares)	2,836,619	2,651,831
Weighted average grant date fair value
Weighted average grant date fair value, beginning balance (in dollars per share)	$35.81	$33.74
Weighted average grant date fair value, granted (in dollars per share)		$36.81
Weighted average grant date fair value, vested (in dollars per share)	$32.25	$29.31
Weighted average grant date fair value, forfeited (in dollars per share)	$41.50	$34.57
Weighted average grant date fair value, ending balance (in dollars per share)	$35.83	$33.80
Restricted share units
Activities
Beginning balance (in shares)	103,484	66,518
Vested (in shares)	-1,997
Issued in lieu of cash dividends (in shares)	747	495
Forfeited (in shares)	-893
Ending balance (in shares)	101,341	67,013
Weighted average grant date fair value
Weighted average grant date fair value, beginning balance (in dollars per share)	$36.54	$33.74
Weighted average grant date fair value, vested (in dollars per share)	$38.24
Weighted average grant date fair value, issued in lieu of cash dividends (in dollars per share)	$36.54	$33.74
Weighted average grant date fair value, forfeited (in dollars per share)	$35.42
Weighted average grant date fair value, ending balance (in dollars per share)	$36.51	$33.74
Performance shares
Activities
Beginning balance (in shares)		101,820	106,369
Conversion adjustment (in shares)		-15,344
Ending balance (in shares)	106,369	86,476	106,369
Weighted average grant date fair value
Weighted average grant date fair value, beginning balance (in dollars per share)		$33.56	$36.03
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)	$36.03	$33.95	$36.03

Stock_plans_Components_of_shar

Stock plans (Components of share compensation expenses) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Total share compensation expenses
Share compensation expenses	$9,054	$7,147
Restricted share awards
Total share compensation expenses
Share compensation expenses	8,479	7,001
Restricted share units
Total share compensation expenses
Share compensation expenses	262	166
Performance shares
Total share compensation expenses
Share compensation expenses	$313	($20)

Stock_plans_Narrative_Details

Stock plans (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
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	905,848
Share compensation expenses	$9,054	$7,147
Options
Stock plans (other details)
Life of options	10 years
Share compensation expenses	0	0
Unrecognized share compensation expenses	0		0
Restricted share awards
Stock plans (other details)
Share compensation expenses	8,479	7,001
Unrecognized share compensation expenses	66,382		74,670
Weighted average period of recognizing share based compensation expenses	2 years 7 months 6 days		2 years 8 months 12 days
Restricted share units
Stock plans (other details)
Share compensation expenses	262	166
Unrecognized share compensation expenses	2,493		2,774
Weighted average period of recognizing share based compensation expenses	2 years 10 months 24 days		3 years 1 month 6 days
Performance shares
Stock plans (other details)
Share compensation expenses	313	-20
Unrecognized share compensation expenses	$1,937		$2,232
Weighted average period of recognizing share based compensation expenses	1 year 10 months 24 days		2 years 1 month 6 days
Performance share awards performance period	3 years

Debt_and_financing_arrangement2

Debt and financing arrangements (Schedule of finance structure) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instruments [Line Items]
Debt instrument, commitment	$847,761		$849,477
Debt instrument, issued and outstanding	787,561	[1]	789,277	[1]
Debt instrument, drawn	784,894		786,583
Credit facility, commitment	1,275,000		1,605,000
Credit facility, issued and outstanding	560,306	[1]	561,684	[1]
Total debt and financing arrangements, commitment	2,122,761		2,454,477
Total debt and financing arrangements, issued and outstanding	1,347,867	[1]	1,350,961	[1]
$400,000 syndicated unsecured letter of credit facility
Debt Instruments [Line Items]
Credit facility, commitment	400,000		400,000
Credit facility, issued and outstanding	0	[1]	0	[1]
$525,000 syndicated secured letter of credit facility
Debt Instruments [Line Items]
Credit facility, commitment	525,000		525,000
Credit facility, issued and outstanding	268,907	[1]	276,455	[1]
Secured bi-lateral letter of credit facility
Debt Instruments [Line Items]
Credit facility, commitment	30,000		200,000
Credit facility, issued and outstanding	14,747	[1]	15,649	[1]
Talbot FAL facility
Debt Instruments [Line Items]
Credit facility, commitment	25,000		25,000
Credit facility, issued and outstanding	25,000	[1]	25,000	[1]
PaCRe senior secured letter of credit facility
Debt Instruments [Line Items]
Credit facility, commitment	10,000		10,000
Credit facility, issued and outstanding	39	[1]	294	[1]
AlphaCat Re secured letter of credit facility
Debt Instruments [Line Items]
Credit facility, commitment	30,000		30,000		24,800
Credit facility, issued and outstanding	30,000	[1]	30,000	[1]
IPC bi-lateral facility
Debt Instruments [Line Items]
Credit facility, commitment	25,000		40,000
Credit facility, issued and outstanding	12,543	[1]	15,897	[1]
Flagstone bi-lateral facility
Debt Instruments [Line Items]
Credit facility, commitment	230,000		375,000
Credit facility, issued and outstanding	209,070	[1]	198,389	[1]
Total debentures payable
Debt Instruments [Line Items]
Debt instrument, commitment	597,761		599,477
Debt instrument, issued and outstanding	537,561	[1]	539,277	[1]
Debt instrument, drawn	537,561		539,277
2006 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Debt instrument, commitment	150,000		150,000
Debt instrument, issued and outstanding	150,000	[1]	150,000	[1]
Debt instrument, drawn	150,000		150,000
2007 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Debt instrument, commitment	200,000		200,000
Debt instrument, issued and outstanding	139,800	[1]	139,800	[1]
Debt instrument, drawn	139,800		139,800
Flagstone 2006 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Debt instrument, commitment	134,011		135,727
Debt instrument, issued and outstanding	134,011	[1]	135,727	[1]
Debt instrument, drawn	134,011		135,727
Flagstone 2007 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Debt instrument, commitment	113,750		113,750
Debt instrument, issued and outstanding	113,750	[1]	113,750	[1]
Debt instrument, drawn	113,750		113,750
2010 Senior Notes Due 2040
Debt Instruments [Line Items]
Debt instrument, commitment	250,000		250,000
Debt instrument, issued and outstanding	250,000	[1]	250,000	[1]
Debt instrument, drawn	$247,333		$247,306
[1]	Indicates utilization of commitment amount, not necessarily drawn borrowings.

Debt_and_financing_arrangement3

Debt and financing arrangements (Summary of notes and debentures) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Debt Instruments [Line Items]
Commitment	$847,761		$849,477
2006 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Commitment	150,000		150,000
Flagstone 2006 Junior Subordinated Deferrable Interest Notes
Debt Instruments [Line Items]
Commitment	134,011		135,727
2007 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Commitment	200,000		200,000
2010 Senior Notes Due 2040
Debt Instruments [Line Items]
Commitment	250,000		250,000
At Issuance | 2006 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Issuance date	15-Jun-06
Commitment	150,000
Maturity date	15-Jun-36
Fixed interest rate (in percent)	9.07%	[1]
Interest payments due	Quarterly
At Issuance | Flagstone 2006 Junior Subordinated Deferrable Interest Notes
Debt Instruments [Line Items]
Issuance date	23-Aug-06
Commitment	134,011
Maturity date	15-Sep-36
Interest payments due	Quarterly
At Issuance | Flagstone 2006 Junior Subordinated Deferrable Interest Notes | London Interbank Offered Rate (LIBOR) [Member]
Debt Instruments [Line Items]
Spread on variable rate (in percent)	3.54%	[2]
At Issuance | 2007 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Issuance date	21-Jun-07
Commitment	200,000
Maturity date	15-Jun-37
Fixed interest rate (in percent)	8.48%	[1]
Interest payments due	Quarterly
At Issuance | Flagstone 2007 Due July 30 2037
Debt Instruments [Line Items]
Issuance date	8-Jun-07
Commitment	88,750
Maturity date	30-Jul-37
Interest payments due	Quarterly
At Issuance | Flagstone 2007 Due July 30 2037 | London Interbank Offered Rate (LIBOR) [Member]
Debt Instruments [Line Items]
Spread on variable rate (in percent)	3.00%	[2]
At Issuance | Flagstone 2007 Debt Due September 15 2037
Debt Instruments [Line Items]
Issuance date	20-Sep-07
Commitment	25,000
Maturity date	15-Sep-37
Interest payments due	Quarterly
At Issuance | Flagstone 2007 Debt Due September 15 2037 | London Interbank Offered Rate (LIBOR) [Member]
Debt Instruments [Line Items]
Spread on variable rate (in percent)	3.10%	[2]
At Issuance | 2010 Senior Notes Due 2040
Debt Instruments [Line Items]
Issuance date	26-Jan-10
Commitment	250,000
Maturity date	26-Jan-40
Fixed interest rate (in percent)	8.88%	[1]
Interest payments due	Semi-annually in arrears
Outstanding | 2006 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Issuance date	15-Jun-06
Commitment	150,000
Maturity date	15-Jun-36
Effective percentage	5.83%	[3]
Interest payments due	Quarterly
Outstanding | Flagstone 2006 Junior Subordinated Deferrable Interest Notes
Debt Instruments [Line Items]
Issuance date	23-Aug-06
Maturity date	15-Sep-36
Effective percentage	6.46%	[3]
Interest payments due	Quarterly
Outstanding | 2007 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Issuance date	21-Jun-07
Commitment	200,000
Maturity date	15-Jun-37
Effective percentage	5.18%	[3]
Interest payments due	Quarterly
Outstanding | Flagstone 2007 Due July 30 2037
Debt Instruments [Line Items]
Issuance date	8-Jun-07
Commitment	88,750
Maturity date	30-Jul-37
Effective percentage	5.90%	[3]
Interest payments due	Quarterly
Outstanding | Flagstone 2007 Debt Due September 15 2037
Debt Instruments [Line Items]
Issuance date	20-Sep-07
Commitment	25,000
Maturity date	15-Sep-37
Effective percentage	5.98%	[3]
Interest payments due	Quarterly
Outstanding | 2010 Senior Notes Due 2040
Debt Instruments [Line Items]
Issuance date	26-Jan-10
Commitment	$250,000
Maturity date	26-Jan-40
Fixed interest rate (in percent)	8.88%	[1]
Interest payments due	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, 2015		Mar. 31, 2014
Debt Instruments [Line Items]
Finance expenses	$19,852		$15,900
Credit facilities
Debt Instruments [Line Items]
Finance expenses	1,707		1,559
Bank charges
Debt Instruments [Line Items]
Finance expenses	98		113
AlphaCat ILS fund fees
Debt Instruments [Line Items]
Finance expenses	4,428	[1]	677	[1]
Talbot FAL facility
Debt Instruments [Line Items]
Finance expenses	50		-15
2006 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Finance expenses	2,187		2,187
2007 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Finance expenses	1,809		1,809
Flagstone 2006 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Finance expenses	2,218		2,223
Flagstone 2007 Junior Subordinated Deferrable Debentures
Debt Instruments [Line Items]
Finance expenses	1,758		1,750
2010 Senior Notes Due 2040
Debt Instruments [Line Items]
Finance expenses	$5,597		$5,597
[1]	Includes finance expenses incurred by AlphaCat Managers, Ltd. in relation to fund raising for the AlphaCat ILS funds, AlphaCat 2015, AlphaCat 2014 and AlphaCat 2013.

Debt_and_financing_arrangement5

Debt and financing arrangements (Narrative) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Senior Notes and Junior Debentures
Long-term Debt	$537,561		$539,277
Credit Facilities
Credit facility, commitment	1,275,000		1,605,000
Credit facility, issued and outstanding	560,306	[1]	561,684	[1]
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
Line of credit facility initiation date	9-Mar-12
Letter of credit facility period	4 years
Aggregate commitments, maximum	500,000
Credit facility, issued and outstanding	0	[1]	0	[1]
Four-year syndicated secured credit facility
Credit Facilities
Credit facility, commitment	525,000		525,000
Line of credit facility initiation date	9-Mar-12
Letter of credit facility period	4 years
Aggregate commitments, maximum	700,000
Credit facility, issued and outstanding	268,907	[1]	276,455	[1]
Talbot FAL Facility
Credit Facilities
Credit facility, commitment	25,000		25,000
Credit facility, issued and outstanding	25,000	[1]	25,000	[1]
Minimum level of consolidated net worth	3,225,727
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
Minimum Level of Funds at Lloyds	300,000
IPC bi-lateral facility
Credit Facilities
Credit facility, commitment	25,000		40,000
Credit facility, issued and outstanding	12,543	[1]	15,897	[1]
Secured bi-lateral letter of credit facility
Credit Facilities
Credit facility, commitment	30,000		200,000
Credit facility, issued and outstanding	14,747	[1]	15,649	[1]
PaCRe senior secured letter of credit facility
Credit Facilities
Credit facility, commitment	10,000		10,000
Credit facility, issued and outstanding	39	[1]	294	[1]
AlphaCat Re secured letter of credit facility
Credit Facilities
Credit facility, commitment	30,000		30,000		24,800
Credit facility, issued and outstanding	30,000	[1]	30,000	[1]
Flagstone bi-lateral facility
Credit Facilities
Credit facility, commitment	230,000		375,000
Credit facility, issued and outstanding	209,070	[1]	198,389	[1]
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	$537,561
Debt Instrument Redemption Period Duration	5 years
[1]	Indicates utilization of commitment amount, not necessarily drawn borrowings.

Accumulated_other_comprehensiv2

Accumulated other comprehensive loss (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	($8,556)	($617)
Net current period other comprehensive income, net of tax	-4,085	462
Balance, end of period	-12,641	-155
Foreign currency items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	-8,118	-617
Net current period other comprehensive income, net of tax	-3,019	462
Balance, end of period	-11,137	-155
Decrease in minimum pension liability
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	-210
Net current period other comprehensive income, net of tax	-265
Balance, end of period	-475
Losses on cash flow hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	-228
Net current period other comprehensive income, net of tax	-801
Balance, end of period	($1,029)

Commitments_and_contingencies_1

Commitments and contingencies (Investment portfolio) (Details) (Concentrations of credit risk)	3 Months Ended
	Mar. 31, 2015
Concentrations Of Credit Risk [Abstract]
Percent of investment portfolio with a credit rating below the minimum required credit rating of Baa3/BBB-	9.20%
Investment portfolio excluding government and agency securities
Concentrations Of Credit Risk [Abstract]
Maximum aggregate exposure to single issuer, allowed	3.50%
Aggregate exposure to single issuer, actual	0.90%
Bank loan portfolio
Concentrations Of Credit Risk [Abstract]
Total investment portfolio, fair value	6.10%
Investment portfolio excluding bank loans
Concentrations Of Credit Risk [Abstract]
Maximum exposure to risk assets, allowed	35.00%
Holding in aggregate market value permitted with written pre-authorization	10.00%

Commitments_and_contingencies_2

Commitments and contingencies (Lloyd's syndicate) (Details)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2015	Mar. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified	USD ($)	USD ($)	Lloyd's Syndicate 1183	Lloyd's Syndicate 1183	2015 Underwriting year	2014 Underwriting year
			USD ($)	GBP (£)	Lloyd's Syndicate 1183	Lloyd's Syndicate 1183
					USD ($)	USD ($)
Components Of Required Capital [Abstract]
Talbot FAL facility	$1,275,000	$1,605,000			$25,000	$25,000
Group funds					570,100	450,000
Total					595,100	475,000
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 $1.4861	£1 equals $1.4861
Maximum premium levies assessable, amount			$27,864

Commitments_and_contingencies_3

Commitments and contingencies (Aquiline commitment) (Details) (USD $)	3 Months Ended	0 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Oct. 02, 2014	Nov. 07, 2014	Dec. 29, 2014	Dec. 31, 2014
Aquiline Capital Partners II GP Offshore Ltd
Related Party Transaction [Line Items]
Total capital commitment	$50,000
Remaining capital commitment	2,865				7,500
Western World | Aquiline Capital Partners II GP Offshore Ltd
Related Party Transaction [Line Items]
Total capital commitment		10,000
Remaining capital commitment	572				1,499
Aquiline Financial Services Fund III LP
Related Party Transaction [Line Items]
Total capital commitment			100,000
Remaining capital commitment	85,862				100,000
AlphaCat 2015
Related Party Transaction [Line Items]
Total capital commitment				28,000
Remaining capital commitment	2,400				2,400
AlphaCat ILS Funds
Related Party Transaction [Line Items]
Total capital commitment				20,000
Remaining capital commitment	$6,930				$8,000

Commitments_and_contingencies_4

Commitments and contingencies (Other investment commitments) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fixed maturity commitment
Other Commitments [Line Items]
Remaining commitment	$16,343	$7,539
Investment commitment
Other Commitments [Line Items]
Capital commitment	153,000	153,000
Remaining commitment	$81,157	$83,712

Related_party_transactions_Det

Related party transactions (Details) (USD $)	3 Months Ended		0 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Oct. 02, 2014	Dec. 20, 2011	Nov. 07, 2014	Dec. 31, 2014
	Employee
Aquiline Capital Partners LLC
Related Party Transaction [Line Items]
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	1,870	$1,373
Premiums receivable	1,433					335
Reinsurance premiums ceded	29	5
Reinsurance balances payable	4					4
Loss reserves recoverable	1,067					1,063
Earned premium adjustments	783	1,441
Conning Inc
Related Party Transaction [Line Items]
Investment management fees	285	56
Accounts payable and accrued expenses	313					515
Aquiline Capital Partners II GP Offshore Ltd
Related Party Transaction [Line Items]
Accounts payable and accrued expenses	0					0
Percentage of Assignor's interest assumed	100.00%
Total capital commitment	50,000
Partnership fees incurred	448	0
Capital contributions	5,562	0
Aquiline Financial Services Fund II LP
Related Party Transaction [Line Items]
Percentage of Assignor's interest assumed				100.00%
Total capital commitment			10,000	50,000
Aquiline Financial Services Fund III LP
Related Party Transaction [Line Items]
Accounts payable and accrued expenses	0					0
Total capital commitment					100,000
Partnership fees incurred	0	0
Capital contributions	14,138	$0

Earnings_per_share_Details

Earnings per share (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Basic earnings per share
Net income	$212,388	$205,897
Income attributable to noncontrolling interest	-38,977	-43,509
Net income available to Validus	173,411	162,388
Less: Dividends and distributions declared on outstanding warrants	-1,405	-1,552
Income available to common shareholders	172,006	160,836
Weighted average number of common shares outstanding	83,251,243	93,451,999
Basic earnings per share available to common shareholders	$2.07	$1.72
Earnings per diluted share
Net income	212,388	205,897
Income attributable to noncontrolling interest	-38,977	-43,509
Net income available to Validus	173,411	162,388
less: Dividends and distributions declared on outstanding warrants	0	0
Income available to common shareholders	$173,411	$162,388
Weighted average number of common shares outstanding	83,251,243	93,451,999
Weighted average number of diluted common shares outstanding	87,583,129	97,799,519
Earnings per diluted share available to common shareholders	$1.98	$1.66
Other details:
Anti-dilutive securities excluded from the calculation of diluted earnings per share	645	12,498
Warrants
Earnings per diluted share
Weighted average number of diluted common shares outstanding, aggregate	2,745,066	2,716,010
Stock options
Earnings per diluted share
Weighted average number of diluted common shares outstanding, aggregate	473,424	750,369
Unvested restricted shares
Earnings per diluted share
Weighted average number of diluted common shares outstanding, aggregate	1,113,396	881,141

Segment_information_Details

Segment information (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Underwriting income
Gross premiums written	$1,119,498		$1,011,991
Reinsurance premiums ceded	-190,840		-194,908
Net premiums written	928,658		817,083
Change in unearned premiums	-350,904		-334,126
Net premiums earned	577,754		482,957
Underwriting deductions
Losses and loss expenses	240,929		162,671
Policy acquisition costs	98,636		85,649
General and administrative expenses	85,028		74,445
Share compensation expenses	9,054		7,147
Total underwriting deductions	433,647		329,912
Underwriting income (loss)	144,107		153,045
Net investment income	31,021		23,362
Other insurance related income (loss)	4,832		8,037
Finance expenses	-19,852		-15,900
Operating income (loss) before taxes, income from operating affiliates and (income) attributable to operating affiliate investors	160,108		168,544
Tax (expense) benefit	-2,565		40
Income from operating affilates	2,453		4,927
(Income) attributable to operating affiliate investors	-23,206		-31,710
Net operating income (loss)	136,790		141,801
Net realized gains on investments	4,169		3,740
Change in net unrealized gains on investments	72,204	[1]	55,693	[1]
Income from investment affiliate	2,776		5,348
Foreign exchange gains (losses)	-3,551		-6,478
Other income			5,793
Net income	212,388		205,897
Net (income) attributable to noncontrolling interest	-38,977		-43,509
Net income (loss) available (attributable) to Validus	173,411		162,388
Selected ratios:
Net premiums written / Gross premiums written	83.00%	[2]	80.70%	[2]
Losses and loss expenses	41.70%	[2]	33.70%	[2]
Policy acquisition costs	17.10%	[2]	17.70%	[2]
General and administrative expenses	16.30%	[2],[3]	16.90%	[2],[3]
Expense ratio	33.40%	[2]	34.60%	[2]
Combined ratio	75.10%	[2]	68.30%	[2]
Total assets	11,054,450		10,382,950		10,329,939
Operating Segments | Validus Re Segment
Underwriting income
Gross premiums written	711,212		666,163	[4],[5]
Reinsurance premiums ceded	-113,296		-129,817	[5]
Net premiums written	597,916		536,346	[5]
Change in unearned premiums	-344,828		-297,960	[5]
Net premiums earned	253,088		238,386	[5]
Underwriting deductions
Losses and loss expenses	113,128		68,155	[5]
Policy acquisition costs	42,094		39,245	[5]
General and administrative expenses	19,509		18,195	[5]
Share compensation expenses	2,578		2,208	[5]
Total underwriting deductions	177,309		127,803	[5]
Underwriting income (loss)	75,779		110,583	[5]
Net investment income	18,776		18,765	[5]
Other insurance related income (loss)	315		977	[5]
Finance expenses	-3,871		-3,839	[5]
Operating income (loss) before taxes, income from operating affiliates and (income) attributable to operating affiliate investors	90,999		126,486	[5]
Tax (expense) benefit	1,880		578	[5]
Income from operating affilates	0		0	[5]
(Income) attributable to operating affiliate investors	0		0	[5]
Net operating income (loss)	92,879		127,064	[5]
Net realized gains on investments	1,809		2,446	[5]
Change in net unrealized gains on investments	20,578		11,898	[5]
Income from investment affiliate	1,933		5,348	[5]
Foreign exchange gains (losses)	-5,024		-6,176	[5]
Other income			5,793	[5]
Net income	112,175		146,373	[5]
Net (income) attributable to noncontrolling interest	0		0	[5]
Net income (loss) available (attributable) to Validus	112,175		146,373	[5]
Selected ratios:
Net premiums written / Gross premiums written	84.10%	[2]	80.50%	[2],[5]
Losses and loss expenses	44.70%	[2]	28.60%	[2],[5]
Policy acquisition costs	16.70%	[2]	16.50%	[2],[5]
General and administrative expenses	8.70%	[2],[3]	8.50%	[2],[3],[5]
Expense ratio	25.40%	[2]	25.00%	[2],[5]
Combined ratio	70.10%	[2]	53.60%	[2],[5]
Total assets	4,567,449		5,730,615	[5]
Operating Segments | AlphaCat Segment
Underwriting income
Gross premiums written	102,564		84,347
Reinsurance premiums ceded	-4,538		-3,700
Net premiums written	98,026		80,647
Change in unearned premiums	-63,831		-49,964
Net premiums earned	34,195		30,683
Underwriting deductions
Losses and loss expenses	-844		-7,860
Policy acquisition costs	3,660		2,980
General and administrative expenses	4,002		4,128
Share compensation expenses	149		-10
Total underwriting deductions	6,967		-762
Underwriting income (loss)	27,228		31,445
Net investment income	1,585		880
Other insurance related income (loss)	5,771		9,497
Finance expenses	-4,516		-683
Operating income (loss) before taxes, income from operating affiliates and (income) attributable to operating affiliate investors	30,068		41,139
Tax (expense) benefit	0		0
Income from operating affilates	2,453		4,927
(Income) attributable to operating affiliate investors	-23,206		-31,710
Net operating income (loss)	9,315		14,356
Net realized gains on investments	-11		1,225
Change in net unrealized gains on investments	37,535		45,872
Income from investment affiliate	0		0
Foreign exchange gains (losses)	-95		38
Other income			0
Net income	46,744		61,491
Net (income) attributable to noncontrolling interest	-38,977		-43,509
Net income (loss) available (attributable) to Validus	7,767		17,982
Selected ratios:
Net premiums written / Gross premiums written	95.60%	[2]	95.60%	[2]
Losses and loss expenses	-2.50%	[2]	-25.60%	[2]
Policy acquisition costs	10.70%	[2]	9.70%	[2]
General and administrative expenses	12.10%	[2],[3]	13.40%	[2],[3]
Expense ratio	22.80%	[2]	23.10%	[2]
Combined ratio	20.30%	[2]	-2.50%	[2]
Total assets	1,954,260		1,582,014
Operating Segments | Talbot Segment
Underwriting income
Gross premiums written	270,077		290,695
Reinsurance premiums ceded	-91,075		-90,605
Net premiums written	179,002		200,090
Change in unearned premiums	43,587		13,798
Net premiums earned	222,589		213,888
Underwriting deductions
Losses and loss expenses	78,128		102,376
Policy acquisition costs	49,104		44,928
General and administrative expenses	36,494		35,149
Share compensation expenses	2,957		2,582
Total underwriting deductions	166,683		185,035
Underwriting income (loss)	55,906		28,853
Net investment income	6,305		4,686
Other insurance related income (loss)	54		17
Finance expenses	-87		-26
Operating income (loss) before taxes, income from operating affiliates and (income) attributable to operating affiliate investors	62,178		33,530
Tax (expense) benefit	-883		130
Income from operating affilates	0		0
(Income) attributable to operating affiliate investors	0		0
Net operating income (loss)	61,295		33,660
Net realized gains on investments	871		69
Change in net unrealized gains on investments	7,911		2,577
Income from investment affiliate	0		0
Foreign exchange gains (losses)	-485		-150
Other income			0
Net income	69,592		36,156
Net (income) attributable to noncontrolling interest	0		0
Net income (loss) available (attributable) to Validus	69,592		36,156
Selected ratios:
Net premiums written / Gross premiums written	66.30%	[2]	68.80%	[2]
Losses and loss expenses	35.10%	[2]	47.90%	[2]
Policy acquisition costs	22.10%	[2]	21.00%	[2]
General and administrative expenses	17.70%	[2],[3]	17.60%	[2],[3]
Expense ratio	39.80%	[2]	38.60%	[2]
Combined ratio	74.90%	[2]	86.50%	[2]
Total assets	2,933,104		2,975,533
Operating Segments | Western World
Underwriting income
Gross premiums written	56,947
Reinsurance premiums ceded	-3,233
Net premiums written	53,714
Change in unearned premiums	14,168
Net premiums earned	67,882
Underwriting deductions
Losses and loss expenses	50,517
Policy acquisition costs	4,279
General and administrative expenses	10,627
Share compensation expenses	477
Total underwriting deductions	65,900
Underwriting income (loss)	1,982
Net investment income	5,303
Other insurance related income (loss)	263
Finance expenses	0
Operating income (loss) before taxes, income from operating affiliates and (income) attributable to operating affiliate investors	7,548
Tax (expense) benefit	-3,723
Income from operating affilates	0
(Income) attributable to operating affiliate investors	0
Net operating income (loss)	3,825
Net realized gains on investments	1,500
Change in net unrealized gains on investments	7,138
Income from investment affiliate	843
Foreign exchange gains (losses)	0
Net income	13,306
Net (income) attributable to noncontrolling interest	0
Net income (loss) available (attributable) to Validus	13,306
Selected ratios:
Net premiums written / Gross premiums written	94.30%	[2]
Losses and loss expenses	74.40%	[2]
Policy acquisition costs	6.30%	[2]
General and administrative expenses	16.40%	[2],[3]
Expense ratio	22.70%	[2]
Combined ratio	97.10%	[2]
Total assets	1,512,848
Corporate And Eliminations
Underwriting income
Gross premiums written	-21,302		-29,214	[4],[5]
Reinsurance premiums ceded	21,302		29,214	[5]
Net premiums written	0		0	[5]
Change in unearned premiums	0		0	[5]
Net premiums earned	0		0	[5]
Underwriting deductions
Losses and loss expenses	0		0	[5]
Policy acquisition costs	-501		-1,504	[5]
General and administrative expenses	14,396		16,973	[5]
Share compensation expenses	2,893		2,367	[5]
Total underwriting deductions	16,788		17,836	[5]
Underwriting income (loss)	-16,788		-17,836	[5]
Net investment income	-948		-969	[5]
Other insurance related income (loss)	-1,571		-2,454	[5]
Finance expenses	-11,378		-11,352	[5]
Operating income (loss) before taxes, income from operating affiliates and (income) attributable to operating affiliate investors	-30,685		-32,611	[5]
Tax (expense) benefit	161		-668	[5]
Income from operating affilates	0		0	[5]
(Income) attributable to operating affiliate investors	0		0	[5]
Net operating income (loss)	-30,524		-33,279	[5]
Net realized gains on investments	0		0	[5]
Change in net unrealized gains on investments	-958		-4,654	[5]
Income from investment affiliate	0		0	[5]
Foreign exchange gains (losses)	2,053		-190	[5]
Other income			0	[5]
Net income	-29,429		-38,123	[5]
Net (income) attributable to noncontrolling interest	0		0	[5]
Net income (loss) available (attributable) to Validus	-29,429		-38,123	[5]
Selected ratios:
Total assets	$86,789		$94,788	[5]
[1]	Includes the change in net unrealized gains 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 loss (income) attributable to noncontrolling interest.
[2]	Ratios are based on net premiums earned.
[3]	The general and administrative expenses ratio includes share compensation expenses.
[4]	During the first quarter of 2015, certain intercompany reinsurance transactions were presented on a net basis for segmental reporting purposes. As a result, gross premiums written for the Validus Re segment and Corporate & Eliminations were reduced by $12,823 for the three months ended March 31, 2014 for comparative purposes. There was no impact to total gross premiums written on a consolidated basis.
[5]	During the first quarter of 2015, certain intercompany reinsurance transactions were presented on a net basis for segmental reporting purposes. As a result, gross premiums written and reinsurance premiums ceded for the Validus Re segment and Corporate & Eliminations were reduced by $12,823 for the three months ended March 31, 2014 for comparative purposes. There was no impact to total gross premiums written and reinsurance premiums ceded on a consolidated basis.

Segment_information_Segment_ge

Segment information (Segment geographic) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$1,119,498		$1,011,991
Percent of gross premiums written	100.00%		100.00%
United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	435,905		275,721
Percent of gross premiums written	38.90%		27.30%
Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	74,740	[1]	102,356	[1]
Percent of gross premiums written	6.70%	[1]	10.00%	[1]
Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	11,589		16,433
Percent of gross premiums written	1.00%		1.60%
Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	38,644		54,203
Percent of gross premiums written	3.50%		5.40%
Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	28,046		34,907
Percent of gross premiums written	2.50%		3.40%
Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	2,125		644
Percent of gross premiums written	0.20%		0.10%
Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	4,001		5,736
Percent of gross premiums written	0.40%		0.60%
Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	39,413	[2]	34,812	[2]
Percent of gross premiums written	3.50%	[2]	3.40%	[2]
Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	198,558		249,091
Percent of gross premiums written	17.80%		24.50%
Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	172,890	[1]	179,954	[1]
Percent of gross premiums written	15.40%	[1]	17.80%	[1]
Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	312,145	[3]	307,225	[3]
Percent of gross premiums written	27.90%	[3]	30.40%	[3]
Operating Segments | Validus Re Segment
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	711,212		666,163	[4],[5]
Operating Segments | Validus Re Segment | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	338,819		243,032	[4]
Operating Segments | Validus Re Segment | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	34,994	[1]	58,523	[1],[4]
Operating Segments | Validus Re Segment | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	9,868		12,860	[4]
Operating Segments | Validus Re Segment | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	24,506		35,878	[4]
Operating Segments | Validus Re Segment | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	8,878		14,337	[4]
Operating Segments | Validus Re Segment | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	1,384		167	[4]
Operating Segments | Validus Re Segment | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	2,187		2,547	[4]
Operating Segments | Validus Re Segment | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	18,726	[2]	18,795	[2],[4]
Operating Segments | Validus Re Segment | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	100,543		143,107	[4]
Operating Segments | Validus Re Segment | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	85,056	[1]	102,284	[1],[4]
Operating Segments | Validus Re Segment | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	186,794	[3]	177,740	[3],[4]
Operating Segments | AlphaCat Segment
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	102,564		84,347
Operating Segments | AlphaCat Segment | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	13,575		8,698
Operating Segments | AlphaCat Segment | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	5,833	[1]	7,678	[1]
Operating Segments | AlphaCat Segment | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		1,019
Operating Segments | AlphaCat Segment | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	1,768		1,301
Operating Segments | AlphaCat Segment | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		0
Operating Segments | AlphaCat Segment | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0		0
Operating Segments | AlphaCat Segment | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	194		216
Operating Segments | 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 | AlphaCat Segment | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	7,795		10,214
Operating Segments | AlphaCat Segment | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	77,894	[1]	65,435	[1]
Operating Segments | AlphaCat Segment | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	3,300	[3]	0	[3]
Operating Segments | Talbot Segment
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	270,077		290,695
Operating Segments | Talbot Segment | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	28,058		26,311
Operating Segments | Talbot Segment | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	34,942	[1]	37,182	[1]
Operating Segments | Talbot Segment | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	1,876		2,880
Operating Segments | Talbot Segment | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	13,214		18,791
Operating Segments | Talbot Segment | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	22,692		31,239
Operating Segments | Talbot Segment | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	754		538
Operating Segments | Talbot Segment | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	1,698		3,145
Operating Segments | Talbot Segment | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	23,006	[2]	18,404	[2]
Operating Segments | Talbot Segment | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	98,182		112,179
Operating Segments | Talbot Segment | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	21,794	[1]	23,653	[1]
Operating Segments | Talbot Segment | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	122,043	[3]	128,552	[3]
Operating Segments | Western World
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	56,947
Operating Segments | Western World | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	56,947
Operating Segments | Western World | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0	[1]
Operating Segments | Western World | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0
Operating Segments | Western World | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0
Operating Segments | Western World | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0
Operating Segments | Western World | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0
Operating Segments | Western World | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0
Operating Segments | Western World | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0	[2]
Operating Segments | Western World | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0
Operating Segments | Western World | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0	[1]
Operating Segments | Western World | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	0	[3]
Corporate And Eliminations
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	-21,302		-29,214	[4],[5]
Corporate And Eliminations | United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	-1,494		-2,320	[4]
Corporate And Eliminations | Worldwide excluding United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	-1,029	[1]	-1,027	[1],[4]
Corporate And Eliminations | Australia and New Zealand
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	-155		-326	[4]
Corporate And Eliminations | Europe
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	-844		-1,767	[4]
Corporate And Eliminations | Latin America and Caribbean
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	-3,524		-10,669	[4]
Corporate And Eliminations | Japan
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	-13		-61	[4]
Corporate And Eliminations | Canada
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	-78		-172	[4]
Corporate And Eliminations | Rest of the world
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	-2,319	[2]	-2,387	[2],[4]
Corporate And Eliminations | Sub-total, non United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	-7,962		-16,409	[4]
Corporate And Eliminations | Worldwide including United States
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	-11,854	[1]	-11,418	[1],[4]
Corporate And Eliminations | Other location non-specific
Gross premiums written allocated to the territory of coverage exposure
Gross premiums written	$8	[3]	$933	[3],[4]
[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.
[4]	During the first quarter of 2015, certain intercompany reinsurance transactions were presented on a net basis for segmental reporting purposes. As a result, gross premiums written for the Validus Re segment and Corporate & Eliminations were reduced by $12,823 for the three months ended March 31, 2014 for comparative purposes. There was no impact to total gross premiums written on a consolidated basis.
[5]	During the first quarter of 2015, certain intercompany reinsurance transactions were presented on a net basis for segmental reporting purposes. As a result, gross premiums written and reinsurance premiums ceded for the Validus Re segment and Corporate & Eliminations were reduced by $12,823 for the three months ended March 31, 2014 for comparative purposes. There was no impact to total gross premiums written and reinsurance premiums ceded on a consolidated basis.

Segment_information_Narrative_

Segment information (Narrative) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
	segments
Segment Reporting [Abstract]
Number of operating segments	4
Reduction to gross premiums written
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Reclassification adjustment		($12,823)
Reduction to reinsurance premiums ceded
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Reclassification adjustment		($12,823)

Condensed_consolidating_financ2

Condensed consolidating financial information - Condensed Consolidating Balance Sheet (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets
Fixed maturities, at fair value	$5,484,479		$5,532,731
Short-term investments, at fair value	1,183,342	[1]	1,051,074	[1]
Other investments, at fair value	881,995		813,011
Cash and cash equivalents	471,129		577,240		789,920	734,148
Restricted cash	186,423		173,003
Total investments and cash	8,207,368		8,147,059
Investments in affiliates	263,332		261,483
Investment in subsidiaries on an equity basis	0		0
Premiums receivable	1,114,102		707,647
Deferred acquisition costs	240,835		161,295
Prepaid reinsurance premiums	192,694		81,983
Securities lending collateral	5,337		470
Loss reserves recoverable	375,882		377,466		348,407	370,154
Paid losses recoverable	27,034		38,078
Income taxes recoverable	10,597		0
Deferred tax asset	30,847		23,821
Receivable for investments sold	24,803		18,318
Intangible assets	125,508		126,924
Goodwill	195,897		195,897
Accrued investment income	23,230		24,865
Intercompany receivable	0		0
Other assets	216,984		164,633
Total assets	11,054,450		10,329,939		10,382,950
Liabilities
Reserve for losses and loss expenses	3,199,362		3,234,394		2,925,059	3,030,399
Unearned premiums	1,452,179		990,564
Reinsurance balances payable	101,426		127,128
Securities lending payable	5,803		936
Deferred tax liability	13,265		5,541
Payable for investments purchased	123,556		68,574
Accounts payable and accrued expenses	177,944		318,245
Intercompany payable	0		0
Notes payable to operating affiliates	919,684		671,465
Senior notes payable	247,333		247,306
Debentures payable	537,561		539,277
Total liabilities	6,778,113		6,203,430
Redeemable noncontrolling interest	98,777		79,956
Total shareholders' equity available to Validus	3,683,109		3,587,958		3,649,064
Noncontrolling interest	494,451		458,595		540,934
Total liabilities, noncontrolling interests and shareholders’ equity	11,054,450		10,329,939
Consolidation Adjustments
Assets
Fixed maturities, at fair value	-60,200	[2]	-60,200	[2]
Short-term investments, at fair value	0	[2]	0	[2]
Other investments, at fair value	-68,997	[2]	-68,112	[2]
Cash and cash equivalents	0	[2]	0	[2]
Restricted cash	0	[2]	0	[2]
Total investments and cash	-129,197	[2]	-128,312	[2]
Investments in affiliates	0	[2]	0	[2]
Investment in subsidiaries on an equity basis	-4,928,475	[2]	-4,797,508	[2]
Premiums receivable	0	[2]	0	[2]
Deferred acquisition costs	0	[2]	0	[2]
Prepaid reinsurance premiums	0	[2]	0	[2]
Securities lending collateral	0	[2]	0	[2]
Loss reserves recoverable	0	[2]	0	[2]
Paid losses recoverable	0	[2]	0	[2]
Income taxes recoverable	0	[2]
Deferred tax asset	0	[2]	0	[2]
Receivable for investments sold	0	[2]	0	[2]
Intangible assets	0	[2]	0	[2]
Goodwill	0	[2]	0	[2]
Accrued investment income	0	[2]	0	[2]
Intercompany receivable	-7,592	[2]	-41,098	[2]
Other assets	0	[2]	0	[2]
Total assets	-5,065,264	[2]	-4,966,918	[2]
Liabilities
Reserve for losses and loss expenses	0	[2]	0	[2]
Unearned premiums	0	[2]	0	[2]
Reinsurance balances payable	0	[2]	0	[2]
Securities lending payable	0	[2]	0	[2]
Deferred tax liability	0	[2]	0	[2]
Payable for investments purchased	0	[2]	0	[2]
Accounts payable and accrued expenses	0	[2]	0	[2]
Intercompany payable	-7,592	[2]	-41,098	[2]
Notes payable to operating affiliates	0	[2]	0	[2]
Senior notes payable	0	[2]	0	[2]
Debentures payable	-60,200	[2]	-60,200	[2]
Total liabilities	-67,792	[2]	-101,298	[2]
Redeemable noncontrolling interest	0	[2]	0	[2]
Total shareholders' equity available to Validus	-4,997,472	[2]	-4,865,620	[2]
Noncontrolling interest	0	[2]	0	[2]
Total liabilities, noncontrolling interests and shareholders’ equity	-5,065,264	[2]	-4,966,918	[2]
Validus Holdings, Ltd. (Parent Guarantor)
Assets
Fixed maturities, at fair value	28,817		0
Short-term investments, at fair value	0		0
Other investments, at fair value	0		0
Cash and cash equivalents	24,148		29,798
Restricted cash	0		0
Total investments and cash	52,965		29,798
Investments in affiliates	0		0
Investment in subsidiaries on an equity basis	4,249,633		4,140,770
Premiums receivable	0		0
Deferred acquisition costs	0		0
Prepaid reinsurance premiums	0		0
Securities lending collateral	0		0
Loss reserves recoverable	0		0
Paid losses recoverable	0		0
Income taxes recoverable	0
Deferred tax asset	0		0
Receivable for investments sold	0		0
Intangible assets	0		0
Goodwill	0		0
Accrued investment income	115		0
Intercompany receivable	0		41,078
Other assets	2,758		3,239
Total assets	4,305,471		4,214,885
Liabilities
Reserve for losses and loss expenses	0		0
Unearned premiums	0		0
Reinsurance balances payable	0		0
Securities lending payable	0		0
Deferred tax liability	0		0
Payable for investments purchased	0		0
Accounts payable and accrued expenses	17,495		29,621
Intercompany payable	7,534		0
Notes payable to operating affiliates	0		0
Senior notes payable	247,333		247,306
Debentures payable	350,000		350,000
Total liabilities	622,362		626,927
Redeemable noncontrolling interest	0		0
Total shareholders' equity available to Validus	3,683,109		3,587,958
Noncontrolling interest	0		0
Total liabilities, noncontrolling interests and shareholders’ equity	4,305,471		4,214,885
Validus Holdings (UK) plc (Subsidiary Issuer)
Assets
Fixed maturities, at fair value	0		0
Short-term investments, at fair value	0		0
Other investments, at fair value	0		0
Cash and cash equivalents	20		81
Restricted cash	0		0
Total investments and cash	20		81
Investments in affiliates	0		0
Investment in subsidiaries on an equity basis	678,842		656,738
Premiums receivable	0		0
Deferred acquisition costs	0		0
Prepaid reinsurance premiums	0		0
Securities lending collateral	0		0
Loss reserves recoverable	0		0
Paid losses recoverable	0		0
Income taxes recoverable	0
Deferred tax asset	0		0
Receivable for investments sold	0		0
Intangible assets	0		0
Goodwill	0		0
Accrued investment income	0		0
Intercompany receivable	0		0
Other assets	0		0
Total assets	678,862		656,819
Liabilities
Reserve for losses and loss expenses	0		0
Unearned premiums	0		0
Reinsurance balances payable	0		0
Securities lending payable	0		0
Deferred tax liability	0		0
Payable for investments purchased	0		0
Accounts payable and accrued expenses	0		96
Intercompany payable	58		20
Notes payable to operating affiliates	0		0
Senior notes payable	0		0
Debentures payable	0		0
Total liabilities	58		116
Redeemable noncontrolling interest	0		0
Total shareholders' equity available to Validus	678,804		656,703
Noncontrolling interest	0		0
Total liabilities, noncontrolling interests and shareholders’ equity	678,862		656,819
Other Validus Holdings, Ltd. Subsidiaries (Non-guarantor Subsidiaries)
Assets
Fixed maturities, at fair value	5,515,862	[3]	5,592,931	[3]
Short-term investments, at fair value	1,183,342	[3]	1,051,074	[3]
Other investments, at fair value	950,992	[3]	881,123	[3]
Cash and cash equivalents	446,961	[3]	547,361	[3]
Restricted cash	186,423	[3]	173,003	[3]
Total investments and cash	8,283,580	[3]	8,245,492	[3]
Investments in affiliates	263,332	[3]	261,483	[3]
Investment in subsidiaries on an equity basis	0	[3]	0	[3]
Premiums receivable	1,114,102	[3]	707,647	[3]
Deferred acquisition costs	240,835	[3]	161,295	[3]
Prepaid reinsurance premiums	192,694	[3]	81,983	[3]
Securities lending collateral	5,337	[3]	470	[3]
Loss reserves recoverable	375,882	[3]	377,466	[3]
Paid losses recoverable	27,034	[3]	38,078	[3]
Income taxes recoverable	10,597	[3]
Deferred tax asset	30,847	[3]	23,821	[3]
Receivable for investments sold	24,803	[3]	18,318	[3]
Intangible assets	125,508	[3]	126,924	[3]
Goodwill	195,897	[3]	195,897	[3]
Accrued investment income	23,115	[3]	24,865	[3]
Intercompany receivable	7,592	[3]	20	[3]
Other assets	214,226	[3]	161,394	[3]
Total assets	11,135,381	[3]	10,425,153	[3]
Liabilities
Reserve for losses and loss expenses	3,199,362	[3]	3,234,394	[3]
Unearned premiums	1,452,179	[3]	990,564	[3]
Reinsurance balances payable	101,426	[3]	127,128	[3]
Securities lending payable	5,803	[3]	936	[3]
Deferred tax liability	13,265	[3]	5,541	[3]
Payable for investments purchased	123,556	[3]	68,574	[3]
Accounts payable and accrued expenses	160,449	[3]	288,528	[3]
Intercompany payable	0	[3]	41,078	[3]
Notes payable to operating affiliates	919,684	[3]	671,465	[3]
Senior notes payable	0	[3]	0	[3]
Debentures payable	247,761	[3]	249,477	[3]
Total liabilities	6,223,485	[3]	5,677,685	[3]
Redeemable noncontrolling interest	98,777	[3]	79,956	[3]
Total shareholders' equity available to Validus	4,318,668	[3]	4,208,917	[3]
Noncontrolling interest	494,451	[3]	458,595	[3]
Total liabilities, noncontrolling interests and shareholders’ equity	$11,135,381	[3]	$10,425,153	[3]
[1]	Included in the short-term investments balance are assets managed in support of AlphaCat's fully collateralized reinsurance transactions. Also, included in the short-term 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.
[2]	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
[3]	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.

Condensed_consolidating_financ3

Condensed consolidating financial information - Condensed Consolidating Statement of Comprehensive Income (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Revenues
Net premiums earned	$577,754		$482,957
Net investment income	31,021		23,362
Net realized gains on investments	4,169		3,740
Change in net unrealized gains on investments	72,204	[1]	55,693	[1]
Income from investment affiliate	2,776		5,348
Other insurance related income and other income	4,832		13,830
Foreign exchange gains (losses)	-3,551		-6,478
Total revenues	689,205		578,452
Expenses
Losses and loss expenses	240,929		162,671
Policy acquisition costs	98,636		85,649
General and administrative expenses	85,028		74,445
Share compensation expenses	9,054		7,147
Finance expenses	19,852		15,900
Total expenses	453,499		345,812
(Loss) income before taxes, income from operating affiliates, (income) attributable to operating affiliate investors and equity in net earnings of subsidiaries	235,706		232,640
Tax (expense) benefit	-2,565		40
Income from operating affiliates	2,453		4,927
(Income) attributable to operating affiliate investors	-23,206		-31,710
Equity in net earnings of subsidiaries	0		0
Net income	212,388		205,897
Net (income) attributable to noncontrolling interest	-38,977		-43,509
Net income available to Validus	173,411		162,388
Other comprehensive (loss)	-4,085		462
Comprehensive income available to Validus	169,326		162,850
Consolidation Adjustments
Revenues
Net premiums earned	0	[2]	0	[2]
Net investment income	-1,005	[2]	-972	[2]
Net realized gains on investments	0	[2]	0	[2]
Change in net unrealized gains on investments	-885	[2]	4,228	[2]
Income from investment affiliate	0	[2]	0	[2]
Other insurance related income and other income	-14,791	[2]	-17,962	[2]
Foreign exchange gains (losses)	0	[2]	0	[2]
Total revenues	-16,681	[2]	-14,706	[2]
Expenses
Losses and loss expenses	0	[2]	0	[2]
Policy acquisition costs	0	[2]	0	[2]
General and administrative expenses	-14,793	[2]	-17,962	[2]
Share compensation expenses	0	[2]	0	[2]
Finance expenses	-481	[2]	-480	[2]
Total expenses	-15,274	[2]	-18,442	[2]
(Loss) income before taxes, income from operating affiliates, (income) attributable to operating affiliate investors and equity in net earnings of subsidiaries	-1,407	[2]	3,736	[2]
Tax (expense) benefit	0	[2]	0	[2]
Income from operating affiliates	0	[2]	0	[2]
(Income) attributable to operating affiliate investors	0	[2]	0	[2]
Equity in net earnings of subsidiaries	-224,167	[2]	-195,499	[2]
Net income	-225,574	[2]	-191,763	[2]
Net (income) attributable to noncontrolling interest	0	[2]	0	[2]
Net income available to Validus	-225,574	[2]	-191,763	[2]
Other comprehensive (loss)	3,284	[2]	-462	[2]
Comprehensive income available to Validus	-222,290	[2]	-192,225	[2]
Validus Holdings, Ltd. (Parent Guarantor)
Revenues
Net premiums earned	0		0
Net investment income	57		3
Net realized gains on investments	0		0
Change in net unrealized gains on investments	-73		0
Income from investment affiliate	0		0
Other insurance related income and other income	0		0
Foreign exchange gains (losses)	510		-168
Total revenues	494		-165
Expenses
Losses and loss expenses	0		0
Policy acquisition costs	0		0
General and administrative expenses	17,543		20,563
Share compensation expenses	1,654		1,308
Finance expenses	11,858		11,823
Total expenses	31,055		33,694
(Loss) income before taxes, income from operating affiliates, (income) attributable to operating affiliate investors and equity in net earnings of subsidiaries	-30,561		-33,859
Tax (expense) benefit	0		0
Income from operating affiliates	0		0
(Income) attributable to operating affiliate investors	0		0
Equity in net earnings of subsidiaries	203,972		196,247
Net income	173,411		162,388
Net (income) attributable to noncontrolling interest	0		0
Net income available to Validus	173,411		162,388
Other comprehensive (loss)	-4,085		462
Comprehensive income available to Validus	169,326		162,850
Validus Holdings (UK) plc (Subsidiary Issuer)
Revenues
Net premiums earned	0		0
Net investment income	0		0
Net realized gains on investments	0		0
Change in net unrealized gains on investments	0		0
Income from investment affiliate	0		0
Other insurance related income and other income	0		0
Foreign exchange gains (losses)	0		0
Total revenues	0		0
Expenses
Losses and loss expenses	0		0
Policy acquisition costs	0		0
General and administrative expenses	2		21
Share compensation expenses	0		0
Finance expenses	0		0
Total expenses	2		21
(Loss) income before taxes, income from operating affiliates, (income) attributable to operating affiliate investors and equity in net earnings of subsidiaries	-2		-21
Tax (expense) benefit	0		0
Income from operating affiliates	0		0
(Income) attributable to operating affiliate investors	0		0
Equity in net earnings of subsidiaries	20,195		-748
Net income	20,193		-769
Net (income) attributable to noncontrolling interest	0		0
Net income available to Validus	20,193		-769
Other comprehensive (loss)	0		0
Comprehensive income available to Validus	20,193		-769
Other Validus Holdings, Ltd. Subsidiaries (Non-guarantor Subsidiaries)
Revenues
Net premiums earned	577,754	[3]	482,957	[3]
Net investment income	31,969	[3]	24,331	[3]
Net realized gains on investments	4,169	[3]	3,740	[3]
Change in net unrealized gains on investments	73,162	[3]	51,465	[3]
Income from investment affiliate	2,776	[3]	5,348	[3]
Other insurance related income and other income	19,623	[3]	31,792	[3]
Foreign exchange gains (losses)	-4,061	[3]	-6,310	[3]
Total revenues	705,392	[3]	593,323	[3]
Expenses
Losses and loss expenses	240,929	[3]	162,671	[3]
Policy acquisition costs	98,636	[3]	85,649	[3]
General and administrative expenses	82,276	[3]	71,823	[3]
Share compensation expenses	7,400	[3]	5,839	[3]
Finance expenses	8,475	[3]	4,557	[3]
Total expenses	437,716	[3]	330,539	[3]
(Loss) income before taxes, income from operating affiliates, (income) attributable to operating affiliate investors and equity in net earnings of subsidiaries	267,676	[3]	262,784	[3]
Tax (expense) benefit	-2,565	[3]	40	[3]
Income from operating affiliates	2,453	[3]	4,927	[3]
(Income) attributable to operating affiliate investors	-23,206	[3]	-31,710	[3]
Equity in net earnings of subsidiaries	0	[3]	0	[3]
Net income	244,358	[3]	236,041	[3]
Net (income) attributable to noncontrolling interest	-38,977	[3]	-43,509	[3]
Net income available to Validus	205,381	[3]	192,532	[3]
Other comprehensive (loss)	-3,284	[3]	462	[3]
Comprehensive income available to Validus	$202,097	[3]	$192,994	[3]
[1]	Includes the change in net unrealized gains 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 loss (income) attributable to noncontrolling interest.
[2]	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
[3]	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.

Condensed_consolidating_financ4

Condensed consolidating financial information - Condensed Consolidating Statement of Cash Flows (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	($228,541)		($44,427)
Cash flows provided by (used in) investing activities
Proceeds on sales of investments	1,190,559		984,356
Proceeds on maturities of investments	93,732		124,716
Purchases of fixed maturities	-1,163,707		-782,290
Purchases of short-term investments, net	-133,104		-107,437
(Purchases) sales of other investments, net	-29,291		7,059
Increase in securities lending collateral	-4,867		-1,485
Redemption in operating affiliates	24,150		43,366
(Increase) decrease in restricted cash	-13,420		91,274
Return of capital from subsidiaries	0
Net cash provided by (used in) investing activities	-56,718		359,559
Cash flows provided by (used in) financing activities
Proceeds on issuance of notes payable to operating affiliates	621,864		154,028
Repayments on notes payable to operating affiliates	-365,883		-184,628
Issuance of common shares, net	4,005		2,030
Purchases of common shares under share repurchase program	-58,108		-197,339
Dividends paid	-28,217		-29,330
Increase in securities lending payable	4,867		1,485
Third party investment in redeemable noncontrolling interest	15,700		0
Third party redemption of redeemable noncontrolling interest	0		-10,496
Return of capital to parent	0
Net cash provided by (used in) financing activities	194,228		-264,250
Effect of foreign currency rate changes on cash and cash equivalents	-15,080		4,890
Net (decrease) increase in cash	-106,111		55,772
Cash and cash equivalents, beginning of year	577,240		734,148
Cash and cash equivalents, end of year	471,129		789,920
Operating affiliates
Cash flows provided by (used in) investing activities
Investments in affiliates	-1,070		0
Investment affiliate
Cash flows provided by (used in) investing activities
Investments in affiliates	-19,700		0
Consolidation Adjustments
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	0	[1]	0	[1]
Cash flows provided by (used in) investing activities
Proceeds on sales of investments	0	[1]	0	[1]
Proceeds on maturities of investments	0	[1]	0	[1]
Purchases of fixed maturities	0	[1]	0	[1]
Purchases of short-term investments, net	0	[1]	0	[1]
(Purchases) sales of other investments, net	0	[1]	0	[1]
Increase in securities lending collateral	0	[1]	0	[1]
Redemption in operating affiliates	0	[1]	0	[1]
(Increase) decrease in restricted cash	0	[1]	0	[1]
Return of capital from subsidiaries	-100,000	[1]
Net cash provided by (used in) investing activities	-100,000	[1]	0	[1]
Cash flows provided by (used in) financing activities
Proceeds on issuance of notes payable to operating affiliates	0	[1]	0	[1]
Repayments on notes payable to operating affiliates	0	[1]	0	[1]
Issuance of common shares, net	0	[1]	0	[1]
Purchases of common shares under share repurchase program	0	[1]	0	[1]
Dividends paid	0	[1]	0	[1]
Increase in securities lending payable	0	[1]	0	[1]
Third party investment in redeemable noncontrolling interest	0	[1]
Third party redemption of redeemable noncontrolling interest			0
Return of capital to parent	100,000	[1]
Net cash provided by (used in) financing activities	100,000	[1]	0	[1]
Effect of foreign currency rate changes on cash and cash equivalents	0	[1]	0	[1]
Net (decrease) increase in cash	0	[1]	0	[1]
Cash and cash equivalents, beginning of year	0	[1]	0	[1]
Cash and cash equivalents, end of year	0	[1]	0	[1]
Consolidation Adjustments | Operating affiliates
Cash flows provided by (used in) investing activities
Investments in affiliates	0	[1]
Consolidation Adjustments | Investment affiliate
Cash flows provided by (used in) investing activities
Investments in affiliates	0	[1]
Validus Holdings, Ltd. (Parent Guarantor)
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	5,572		267,177
Cash flows provided by (used in) investing activities
Proceeds on sales of investments	0		0
Proceeds on maturities of investments	0		0
Purchases of fixed maturities	-28,902		0
Purchases of short-term investments, net	0		0
(Purchases) sales of other investments, net	0		0
Increase in securities lending collateral	0		0
Redemption in operating affiliates	0		0
(Increase) decrease in restricted cash	0		0
Return of capital from subsidiaries	100,000
Net cash provided by (used in) investing activities	71,098		0
Cash flows provided by (used in) financing activities
Proceeds on issuance of notes payable to operating affiliates	0		0
Repayments on notes payable to operating affiliates	0		0
Issuance of common shares, net	4,005		2,030
Purchases of common shares under share repurchase program	-58,108		-197,339
Dividends paid	-28,217		-29,330
Increase in securities lending payable	0		0
Third party investment in redeemable noncontrolling interest	0
Third party redemption of redeemable noncontrolling interest			0
Return of capital to parent	0
Net cash provided by (used in) financing activities	-82,320		-224,639
Effect of foreign currency rate changes on cash and cash equivalents	0		0
Net (decrease) increase in cash	-5,650		42,538
Cash and cash equivalents, beginning of year	29,798		20,385
Cash and cash equivalents, end of year	24,148		62,923
Validus Holdings, Ltd. (Parent Guarantor) | Operating affiliates
Cash flows provided by (used in) investing activities
Investments in affiliates	0
Validus Holdings, Ltd. (Parent Guarantor) | Investment affiliate
Cash flows provided by (used in) investing activities
Investments in affiliates	0
Validus Holdings (UK) plc (Subsidiary Issuer)
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	-61		0
Cash flows provided by (used in) investing activities
Proceeds on sales of investments	0		0
Proceeds on maturities of investments	0		0
Purchases of fixed maturities	0		0
Purchases of short-term investments, net	0		0
(Purchases) sales of other investments, net	0		0
Increase in securities lending collateral	0		0
Redemption in operating affiliates	0		0
(Increase) decrease in restricted cash	0		0
Return of capital from subsidiaries	0
Net cash provided by (used in) investing activities	0		0
Cash flows provided by (used in) financing activities
Proceeds on issuance of notes payable to operating affiliates	0		0
Repayments on notes payable to operating affiliates	0		0
Issuance of common shares, net	0		0
Purchases of common shares under share repurchase program	0		0
Dividends paid	0		0
Increase in securities lending payable	0		0
Third party investment in redeemable noncontrolling interest	0
Third party redemption of redeemable noncontrolling interest			0
Return of capital to parent	0
Net cash provided by (used in) financing activities	0		0
Effect of foreign currency rate changes on cash and cash equivalents	0		0
Net (decrease) increase in cash	-61		0
Cash and cash equivalents, beginning of year	81		0
Cash and cash equivalents, end of year	20		0
Validus Holdings (UK) plc (Subsidiary Issuer) | Operating affiliates
Cash flows provided by (used in) investing activities
Investments in affiliates	0
Validus Holdings (UK) plc (Subsidiary Issuer) | Investment affiliate
Cash flows provided by (used in) investing activities
Investments in affiliates	0
Other Validus Holdings, Ltd. Subsidiaries (Non-guarantor Subsidiaries)
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	-234,052	[2]	-311,604	[2]
Cash flows provided by (used in) investing activities
Proceeds on sales of investments	1,190,559	[2]	984,356	[2]
Proceeds on maturities of investments	93,732	[2]	124,716	[2]
Purchases of fixed maturities	-1,134,805	[2]	-782,290	[2]
Purchases of short-term investments, net	-133,104	[2]	-107,437	[2]
(Purchases) sales of other investments, net	-29,291	[2]	7,059	[2]
Increase in securities lending collateral	-4,867	[2]	-1,485	[2]
Redemption in operating affiliates	24,150	[2]	43,366	[2]
(Increase) decrease in restricted cash	-13,420	[2]	91,274	[2]
Return of capital from subsidiaries	0	[2]
Net cash provided by (used in) investing activities	-27,816	[2]	359,559	[2]
Cash flows provided by (used in) financing activities
Proceeds on issuance of notes payable to operating affiliates	621,864	[2]	154,028	[2]
Repayments on notes payable to operating affiliates	-365,883	[2]	-184,628	[2]
Issuance of common shares, net	0	[2]	0	[2]
Purchases of common shares under share repurchase program	0	[2]	0	[2]
Dividends paid	0	[2]	0	[2]
Increase in securities lending payable	4,867	[2]	1,485	[2]
Third party investment in redeemable noncontrolling interest	15,700	[2]
Third party redemption of redeemable noncontrolling interest			-10,496
Return of capital to parent	-100,000	[2]
Net cash provided by (used in) financing activities	176,548	[2]	-39,611	[2]
Effect of foreign currency rate changes on cash and cash equivalents	-15,080	[2]	4,890	[2]
Net (decrease) increase in cash	-100,400	[2]	13,234	[2]
Cash and cash equivalents, beginning of year	547,361	[2]	713,763	[2]
Cash and cash equivalents, end of year	446,961	[2]	726,997	[2]
Other Validus Holdings, Ltd. Subsidiaries (Non-guarantor Subsidiaries) | Operating affiliates
Cash flows provided by (used in) investing activities
Investments in affiliates	-1,070	[2]
Other Validus Holdings, Ltd. Subsidiaries (Non-guarantor Subsidiaries) | Investment affiliate
Cash flows provided by (used in) investing activities
Investments in affiliates	($19,700)	[2]
[1]	Amounts include consolidating adjustments between the Parent Guarantor, the Subsidiary Issuer and the non-guarantor subsidiaries.
[2]	Amounts include an aggregation of the non-guarantor subsidiaries and include consolidating adjustments between these subsidiaries.

Subsequent_events_Details

Subsequent events (Details) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	7-May-15
Subsequent Event [Line Items]
Cash dividends declared per share	$0.32	$0.30
Common shares
Subsequent Event [Line Items]
Cash dividends declared per share	$0.32	$0.30
Common share equivalents
Subsequent Event [Line Items]
Cash dividends declared per share	$0.32
Subsequent Event | Common shares
Subsequent Event [Line Items]
Cash dividends declared per share			$0.32
Subsequent Event | Common share equivalents
Subsequent Event [Line Items]
Cash dividends declared per share			$0.32