RenaissanceRe (RNR) 10-K 20 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 18, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Entity Registrant Name	RENAISSANCERE HOLDINGS LTD.
Trading Symbol	RNR
Entity Central Index Key	913144
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		38,330,334
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$4,203.60

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets
Fixed maturity investments trading, at fair value (Amortized cost $4,749,613 and $4,781,712 at December 31, 2014 and December 31, 2013, respectively) (Notes 5 and 6)	$4,756,685	$4,809,036
Fixed maturity investments available for sale, at fair value (Amortized cost $23,772 and $30,273 at December 31, 2014 and December 31, 2013, respectively) (Notes 5 and 6)	26,885	34,241
Short term investments, at fair value (Notes 5 and 6)	1,013,222	1,044,779
Equity investments trading, at fair value (Notes 5 and 6)	322,098	254,776
Other investments, at fair value (Notes 5 and 6)	504,147	573,264
Investments in other ventures, under equity method (Note 5)	120,713	105,616
Total investments	6,743,750	6,821,712
Cash and cash equivalents	525,584	408,032
Premiums receivable	440,007	474,087
Prepaid reinsurance premiums (Note 7)	94,810	66,132
Reinsurance recoverable (Notes 7 and 8)	66,694	101,025
Accrued investment income	26,509	34,065
Deferred acquisition costs	110,059	81,684
Receivable for investments sold	52,390	75,845
Other assets	135,845	108,438
Goodwill and other intangible assets (Note 4)	7,902	8,111
Total assets	8,203,550	8,179,131
Liabilities
Reserve for claims and claim expenses (Note 8)	1,412,510	1,563,730
Unearned premiums	512,386	477,888
Debt (Note 9)	249,522	249,430
Reinsurance balances payable	454,580	293,022
Payable for investments purchased	203,021	193,221
Other liabilities	374,108	397,596
Total liabilities	3,206,127	3,174,887
Commitments and Contingencies (Note 20)
Redeemable noncontrolling interests (Note 10)	1,131,708	1,099,860
Shareholders’ Equity (Note 12)
Preference shares: $1.00 par value – 16,000,000 shares issued and outstanding at December 31, 2014 (December 31, 2013 – 16,000,000)	400,000	400,000
Common shares: $1.00 par value – 38,441,972 shares issued and outstanding at December 31, 2014 (December 31, 2013 – 43,646,436)	38,442	43,646
Accumulated other comprehensive income	3,416	4,131
Retained earnings	3,423,857	3,456,607
Total shareholders’ equity	3,865,715	3,904,384
Total liabilities, noncontrolling interests and shareholders’ equity	$8,203,550	$8,179,131

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Fixed maturity investments trading, Amortized cost	$4,749,613	$4,781,712
Fixed maturity investments available-for-sale, Amortized cost	$23,772	$30,273
Preference Shares, Par Value (In dollars per share)	$1	$1
Preference Shares, Shares issued (In shares)	16,000,000	16,000,000
Preference shares, Shares outstanding (In shares)	16,000,000	16,000,000
Common Shares, Par Value (In dollars per share)	$1	$1
Common Shares, Shares issued (In shares)	38,441,972	43,646,436
Common Shares, Shares outstanding (In shares)	38,441,972	43,646,436

Consolidated_Statements_Of_Ope

Consolidated Statements Of Operations (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues
Gross premiums written	$132,780	$200,992	$511,540	$705,260	$84,122	$182,649	$703,223	$635,418	$1,550,572	$1,605,412	$1,551,591
Net premiums written (Note 7)	111,769	159,713	346,407	450,347	80,784	127,241	559,109	436,813	1,068,236	1,203,947	1,102,657
Increase in unearned premiums	144,718	99,266	-85,991	-163,813	175,981	167,476	-267,220	-165,558	-5,820	-89,321	-33,302
Net premiums earned (Note 7)	256,487	258,979	260,416	286,534	256,765	294,717	291,889	271,255	1,062,416	1,114,626	1,069,355
Net investment income (Note 5)	25,886	24,941	34,541	38,948	78,732	59,931	26,163	43,202	124,316	208,028	165,725
Net foreign exchange gains	-107	5,036	2,392	-1,061	1,747	488	-932	614	6,260	1,917	5,319
Equity in earnings of other ventures (Note 5)	4,838	9,806	7,232	4,199	6,274	7,313	3,772	5,835	26,075	23,194	23,238
Other loss	1,219	-1,169	-535	62	-173	651	-1,128	-1,709	-423	-2,359	-2,120
Net realized and unrealized gains on investments (Note 5)	30,475	-31,097	27,128	14,927	61,864	28,472	-69,529	14,269	41,433	35,076	163,121
Total other-than-temporary impairments									0	0	-395
Portion recognized in other comprehensive income (loss), before taxes									0	0	52
Net other-than-temporary impairments (Note 5)									0	0	-343
Total revenues	318,798	266,496	331,174	343,609	405,209	391,572	250,235	333,466	1,260,077	1,380,482	1,424,295
Expenses
Net claims and claim expenses incurred (Notes 7 and 8)	-12,003	69,647	81,388	58,915	-20,854	60,928	103,962	27,251	197,947	171,287	325,211
Acquisition expenses	39,749	37,550	33,477	33,700	31,026	37,699	31,767	25,009	144,476	125,501	113,542
Operational expenses	55,202	46,972	45,841	42,624	57,658	44,672	42,789	45,986	190,639	191,105	179,151
Corporate expenses	10,583	3,905	3,954	4,545	3,304	4,307	21,529	4,482	22,987	33,622	16,456
Interest expense (Note 9)	4,289	4,290	4,292	4,293	4,297	4,298	4,300	5,034	17,164	17,929	23,097
Total expenses	97,820	162,364	168,952	144,077	75,431	151,904	204,347	107,762	573,213	539,444	657,457
Income from continuing operations before taxes	220,978	104,132	162,222	199,532	329,778	239,668	45,888	225,704	686,864	841,038	766,838
Income tax expense (Note 15)	-401	-245	204	-166	-1,336	-223	-11	-122	-608	-1,692	-1,413
Income from continuing operations	220,577	103,887	162,426	199,366	328,442	239,445	45,877	225,582	686,256	839,346	765,425
Income (loss) from discontinued operations (Note 3)	0	0	0	0	0	-9,779	2,427	9,774	0	2,422	-16,476
Net income	220,577	103,887	162,426	199,366	328,442	229,666	48,304	235,356	686,256	841,768	748,949
Net income attributable to noncontrolling interests (Note 10)	-44,215	-30,477	-36,078	-42,768	-54,191	-44,331	-14,015	-38,607	-153,538	-151,144	-148,040
Net income attributable to RenaissanceRe	176,362	73,410	126,348	156,598	274,251	185,335	34,289	196,749	532,718	690,624	600,909
Dividends on preference shares (Note 12)	-5,595	-5,595	-5,596	-5,595	-5,595	-5,595	-7,483	-6,275	-22,381	-24,948	-34,895
Net income available to RenaissanceRe common shareholders	$170,767	$67,815	$120,752	$151,003	$268,656	$179,740	$26,806	$190,474	$510,337	$665,676	$566,014
Income (loss) from continuing operations available (attributable) to RenaissanceRe common shareholders per common share – basic, in dollars per share	$4.46	$1.72	$3	$3.61	$6.14	$4.32	$0.55	$4.10	$12.77	$15.08	$11.74
Income (loss) from discontinued operations available (attributable) to RenaissanceRe common shareholders per common share – basic, in dollars per share	$0	$0	$0	$0	$0	($0.23)	$0.06	$0.22	$0	$0.06	($0.34)
Net income available to RenaissanceRe common shareholders per common share – basic (Note 13), in dollars per share	$4.46	$1.72	$3	$3.61	$6.14	$4.09	$0.61	$4.32	$12.77	$15.14	$11.40
Income from continuing operations available to RenaissanceRe common shareholders per common share – diluted, in dollars per share	$4.42	$1.70	$2.95	$3.56	$6.05	$4.23	$0.55	$4.01	$12.60	$14.82	$11.56
Income (loss) from discontinued operations available (attributable) to RenaissanceRe common shareholders per common share – diluted, in dollars per share	$0	$0	$0	$0	$0	($0.22)	$0.05	$0.22	$0	$0.05	($0.33)
Net income available to RenaissanceRe common shareholders per common share – diluted (Note 13), in dollars per share	$4.42	$1.70	$2.95	$3.56	$6.05	$4.01	$0.60	$4.23	$12.60	$14.87	$11.23
Dividends per common share (Note 12), in dollars per share									$1.16	$1.12	$1.08

Consolidated_Statements_Of_Com

Consolidated Statements Of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Comprehensive income
Net income	$686,256	$841,768	$748,949
Change in net unrealized gains on investments	-715	-9,491	1,914
Portion of other-than-temporary impairments recognized in other comprehensive income, before taxes	0	0	-52
Comprehensive income	685,541	832,277	750,811
Net income attributable to noncontrolling interests	-153,538	-151,144	-148,040
Comprehensive income attributable to noncontrolling interests	-153,538	-151,144	-148,040
Comprehensive income attributable to RenaissanceRe	532,003	681,133	602,771
Disclosure regarding net unrealized gains
Total net realized and unrealized holding (losses) gains on investments and net other-than-temporary impairments	-715	-1,943	5,100
Net realized gains on fixed maturity investments available for sale	0	-7,548	-3,529
Net other-than-temporary impairments recognized in earnings	0	0	343
Change in net unrealized gains on investments	($715)	($9,491)	$1,914

Consolidated_Statements_Of_Cha

Consolidated Statements Of Changes In Shareholders' Equity (USD $)	Total	Preference shares	Common stock	Additional paid-in capital	Accumulated other comprehensive income	Retained earnings	Noncontrolling interest
In Thousands, unless otherwise specified
Beginning of period at Dec. 31, 2011		$550,000	$51,543	$0	$11,760	$2,991,890
Statement of Changes in Stockholders' Equity
Issuance of shares		0
Repurchase of shares		-150,000	-6,399	-27,376		-460,647
Offering expenses				0
Change in redeemable noncontrolling interest				9,091
Exercise of options and issuance of restricted stock awards (Notes 12 and 17)			398	18,285
Change in net unrealized gains on investments	-1,914				1,914
Portion of other-than-temporary impairments recognized in other comprehensive income (loss)					-52
Net income	748,949					748,949
Net income attributable to noncontrolling interests (Note 10)	-148,040					-148,040
Dividends on common shares						-53,356
Dividends on preference shares	-34,895					-34,895
Noncontrolling interest (Note 10)							3,991
Total shareholders’ equity	3,507,056
End of period at Dec. 31, 2012		400,000	45,542	0	13,622	3,043,901
Statement of Changes in Stockholders' Equity
Issuance of shares		275,000
Repurchase of shares		-275,000	-2,451	-1,702		-203,703
Offering expenses				-9,144
Change in redeemable noncontrolling interest				318
Exercise of options and issuance of restricted stock awards (Notes 12 and 17)			555	10,528
Change in net unrealized gains on investments	9,491				-9,491
Portion of other-than-temporary impairments recognized in other comprehensive income (loss)					0
Net income	841,768					841,768
Net income attributable to noncontrolling interests (Note 10)	-151,144					-151,144
Dividends on common shares						-49,267
Dividends on preference shares	-24,948					-24,948
Noncontrolling interest (Note 10)							0
Total shareholders’ equity	3,904,384
End of period at Dec. 31, 2013		400,000	43,646	0	4,131	3,456,607
Statement of Changes in Stockholders' Equity
Issuance of shares		0
Repurchase of shares		0	-5,355	-11,702		-497,175
Offering expenses				0
Change in redeemable noncontrolling interest				1,274
Exercise of options and issuance of restricted stock awards (Notes 12 and 17)			151	10,428
Change in net unrealized gains on investments	715				-715
Portion of other-than-temporary impairments recognized in other comprehensive income (loss)					0
Net income	686,256					686,256
Net income attributable to noncontrolling interests (Note 10)	-153,538					-153,538
Dividends on common shares						-45,912
Dividends on preference shares	-22,381					-22,381
Noncontrolling interest (Note 10)							0
Total shareholders’ equity	3,865,715
End of period at Dec. 31, 2014		$400,000	$38,442	$0	$3,416	$3,423,857

Consolidated_Statements_Of_Cas

Consolidated Statements Of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows provided by operating activities
Net income	$686,256,000	$841,768,000	$748,949,000
Adjustments to reconcile net income to net cash provided by operating activities
Amortization, accretion and depreciation	47,771,000	51,596,000	59,695,000
Equity in undistributed earnings of other ventures	-19,990,000	-15,450,000	-19,316,000
Net realized and unrealized gains on investments	-41,433,000	-35,058,000	-163,121,000
Net other-than-temporary impairments	0	0	343,000
Net unrealized losses (gains) included in net investment income	1,393,000	-75,789,000	-38,207,000
Net unrealized losses (gains) included in other loss	1,612,000	12,782,000	-330,000
Change in:
Premiums receivable	34,080,000	17,278,000	-19,487,000
Prepaid reinsurance premiums	-28,678,000	10,950,000	-18,560,000
Reinsurance recoverable	34,331,000	91,487,000	211,517,000
Deferred acquisition costs	-28,375,000	-29,062,000	-8,901,000
Reserve for claims and claim expenses	-151,220,000	-315,647,000	-112,977,000
Unearned premiums	34,498,000	78,371,000	51,862,000
Reinsurance balances payable	161,558,000	2,603,000	33,536,000
Other	-71,146,000	159,892,000	-8,074,000
Net cash provided by operating activities	660,657,000	795,721,000	716,929,000
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	7,682,573,000	8,251,405,000	8,192,867,000
Purchases of fixed maturity investments trading	-7,639,178,000	-8,466,467,000	-8,536,238,000
Proceeds from sales and maturities of fixed maturity investments available for sale	7,088,000	45,178,000	65,168,000
Net purchases of equity investments trading	-20,003,000	-33,055,000	0
Net sales (purchases) of short term investments	45,023,000	-246,971,000	68,777,000
Net sales of other investments	59,120,000	76,214,000	150,828,000
Net sales (purchases) of investments in other ventures	1,030,000	-4,000,000	0
Net sales (purchases) of other assets	6,000,000	2,181,000	-4,079,000
Net proceeds (payments) related to sale of discontinued operations	0	60,000,000	-9,000,000
Net cash provided by (used in) investing activities	141,653,000	-315,515,000	-71,677,000
Cash flows used in financing activities
Dividends paid – RenaissanceRe common shares	-45,912,000	-49,267,000	-53,356,000
Dividends paid – preference shares	-22,381,000	-24,948,000	-34,895,000
RenaissanceRe common share repurchases	-514,678,000	-207,410,000	-463,309,000
Net repayment of debt	0	-102,436,000	-1,937,000
Redemption of preference shares		-125,000,000	-150,000,000
Net third party redeemable noncontrolling interest share transactions	-111,707,000	-5,750,000	164,927,000
Net cash used in financing activities	-694,678,000	-398,955,000	-538,570,000
Effect of exchange rate changes on foreign currency cash	9,920,000	1,423,000	1,692,000
Net increase in cash and cash equivalents	117,552,000	82,674,000	108,374,000
Net decrease in cash and cash equivalents of discontinued operations	0	21,213,000	13,946,000
Cash and cash equivalents, beginning of period	408,032,000	304,145,000	181,825,000
Cash and cash equivalents, end of period	525,584,000	408,032,000	304,145,000
Series C Preferred Stock
Cash flows used in financing activities
Redemption of preference shares	0	-125,000,000	0
Series D Preferred Stock
Cash flows used in financing activities
Redemption of preference shares	0	-150,000,000	-150,000,000
Series E Preferred Stock
Cash flows used in financing activities
Issuance of 5.375% Series E preference shares, net of expenses	$0	$265,856,000	$0

Organization

Organization	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	ORGANIZATION
	RenaissanceRe Holdings Ltd. (“RenaissanceRe”) was formed under the laws of Bermuda on June 7, 1993. Together with its wholly owned and majority-owned subsidiaries and DaVinciRe (as defined below), which are collectively referred to herein as the “Company”, RenaissanceRe provides reinsurance and insurance coverages and related services to a broad range of customers.
	•	Renaissance Reinsurance Ltd. (“Renaissance Reinsurance”), the Company’s principal reinsurance subsidiary, provides property catastrophe and specialty reinsurance coverages to insurers and reinsurers on a worldwide basis.
	•	The Company also manages property catastrophe and specialty reinsurance business written on behalf of joint ventures, which principally include Top Layer Reinsurance Ltd. (“Top Layer Re”), recorded under the equity method of accounting, and DaVinci Reinsurance Ltd. (“DaVinci”). Because the Company owns a noncontrolling equity interest in, but controls a majority of the outstanding voting power of DaVinci’s parent, DaVinciRe Holdings Ltd. (“DaVinciRe”), the results of DaVinci and DaVinciRe are consolidated in the Company’s financial statements. Redeemable noncontrolling interest – DaVinciRe represents the interests of external parties with respect to the net income and shareholders’ equity of DaVinciRe. Renaissance Underwriting Managers, Ltd. (“RUM”), a wholly owned subsidiary, acts as exclusive underwriting manager for these joint ventures in return for fee-based income and profit participation.
	•	RenaissanceRe Syndicate 1458 (“Syndicate 1458”) is the Company’s Lloyd’s syndicate. RenaissanceRe Corporate Capital (UK) Limited (“RenaissanceRe CCL”), a wholly owned subsidiary of RenaissanceRe, is Syndicate 1458’s sole corporate member and RenaissanceRe Syndicate Management Ltd. (“RSML”), a wholly owned subsidiary of RenaissanceRe, is the managing agent for Syndicate 1458.
	•	RenaissanceRe Specialty Risks Ltd. (“RenaissanceRe Specialty Risks”), is a Bermuda-domiciled excess and surplus lines insurance company that is listed on the National Association of Insurance Commissioners’ International Insurance Department’s Quarterly List of Alien Insurers as an eligible surplus lines insurer. RenaissanceRe Underwriting Managers U.S. LLC, a specialty reinsurance agency domiciled in Connecticut, provides specialty treaty reinsurance solutions on both a quota share and excess of loss basis; and writes business on behalf of RenaissanceRe Specialty U.S. Ltd. (“RenaissanceRe Specialty U.S.”), a Bermuda-domiciled reinsurer launched in June 2013 which operates subject to U.S. federal income tax, and Syndicate 1458.
	•	Effective January 1, 2013, the Company formed and launched a managed joint venture, Upsilon Reinsurance II Ltd. (“Upsilon Re II”), a Bermuda domiciled special purpose insurer (“SPI”), to provide additional capacity to the worldwide aggregate and per-occurrence primary and retrocessional property catastrophe excess of loss market. Effective December 11, 2013, Upsilon Re II was renamed Upsilon Reinsurance Fund Opportunities Ltd. (“Upsilon RFO”). Upsilon RFO is considered a variable interest entity (“VIE”) and the Company is considered the primary beneficiary. As a result, Upsilon RFO is consolidated by the Company and all significant inter-company transactions have been eliminated.
	•	Effective November 13, 2014, the Company incorporated RenaissanceRe Upsilon Fund Ltd. (“Upsilon Fund”), an exempted Bermuda limited segregated accounts company. Upsilon Fund was formed to provide a fund structure through which third party investors can invest in reinsurance risk managed by the Company. As a segregated accounts company, Upsilon Fund is permitted to establish segregated accounts to invest in and hold identified pools of assets and liabilities. Each pool of assets and liabilities in each segregated account is ring-fenced from any claims from the creditors of Upsilon Fund’s general account and from the creditors of other segregated accounts within Upsilon Fund. Third party investors purchase redeemable, non voting preference shares linked to specific segregated accounts of Upsilon Fund and own 100% of these shares. Upsilon Fund is an investment company and is considered a VIE. The Company is not considered the primary beneficiary of Upsilon Fund and as a result it is not consolidated by the Company.
	•	RenaissanceRe Medici Fund Ltd. (“Medici”) is an exempted fund, incorporated under the laws of Bermuda. Medici’s objective is to seek to invest substantially all of its assets in various insurance-based investment instruments that have returns primarily tied to property catastrophe risk. Third-party investors have subscribed for a portion of the participating, non-voting common shares of Medici. Because the Company owns a noncontrolling equity interest in, but controls a majority of the outstanding voting power of Medici’s parent, RenaissanceRe Fund Holdings Ltd. (“Fund Holdings”), the results of Medici and Fund Holdings are consolidated in the Company’s financial statements. Redeemable noncontrolling interest - Medici represents the interests of external parties with respect to the net income and shareholders’ equity of Medici.
	•	On August 30, 2013, the Company entered into a purchase agreement with a subsidiary of Munich-American Holding Corporation (together with applicable affiliates, “Munich”) to sell its U.S.-based weather and weather-related energy risk management unit, which included RenRe Commodity Advisors LLC (“RRCA”), Renaissance Trading Ltd. (“Renaissance Trading”) and RenRe Energy Advisors Ltd. (collectively referred to as “REAL”). REAL offered certain derivative-based risk management products primarily to address weather and energy risk and engaged in hedging and trading activities related to those transactions. On October 1, 2013, the Company closed the sale of REAL to Munich. In the third quarter of 2013, the Company classified the assets and liabilities associated with this transaction as held for sale. The financial results for these operations have been presented in the Company’s consolidated financial statements as “discontinued operations” for all periods presented. Refer to “Note 3. Discontinued Operations”, for more information.
	•	On November 24, 2014, the Company announced that RenaissanceRe and Platinum Underwriters Holdings, Ltd. (“Platinum”) entered into a definitive merger agreement (the “Merger Agreement”) under which RenaissanceRe will acquire Platinum (the “Merger”). The agreement has been unanimously approved by both companies’ Board of Directors and, if approved by Platinum shareholders, the transaction is expected to close on March 2, 2015. The aggregate consideration for the transaction is expected to be approximately $1.9 billion.  The Company will account for the acquisition of Platinum under the acquisition method of accounting in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 805 Business Combinations, under which the total consideration paid will be allocated among acquired assets and assumed liabilities based on the fair values of the assets acquired and liabilities assumed.  The Company anticipates that the purchase price paid will exceed the fair value of the net assets acquired, perhaps significantly so, and the excess will be accounted for as goodwill.  Intangible assets with definite lives will be amortized over their estimated useful lives.  Goodwill resulting from the acquisition of Platinum will not be amortized but instead will be tested for impairment at least annually (more frequently if certain indicators are present). There can be no assurance that the Merger will occur. Refer to “Note 20. Commitments, Contingencies and Other Items”, for more information with respect to the Merger.

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Significant Accounting Policies	SIGNIFICANT ACCOUNTING POLICIES
	BASIS OF PRESENTATION
	These consolidated financial statements have been prepared on the basis of accounting principles generally accepted in the United States (“GAAP”). All significant intercompany accounts and transactions have been eliminated from these statements. Except as discussed in “Note 3. Discontinued Operations,” and unless otherwise noted, the notes to the consolidated financial statements reflect the Company’s continuing operations.
	Certain comparative information has been reclassified to conform to the current presentation.
	USE OF ESTIMATES IN FINANCIAL STATEMENTS
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported and disclosed 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. Actual results could differ materially from those estimates. The major estimates reflected in the Company’s consolidated financial statements include, but are not limited to, the reserve for claims and claim expenses; reinsurance recoverables, including allowances for reinsurance recoverables deemed uncollectible; estimates of written and earned premiums; fair value, including the fair value of investments, financial instruments and derivatives; impairment charges; and the Company’s deferred tax valuation allowance.
	DISCONTINUED OPERATIONS
	The results of operations of substantially all of the Company’s U.S.-based insurance operations and REAL, its U.S.-based weather and weather-related energy risk management unit, each of which has been sold to a separate unaffiliated third party, are classified as held for sale and are reported as discontinued operations in accordance with FASB ASC Topic Discontinued Operations. The consolidated financial statements and notes thereto are presented excluding the operations and cash flows of the discontinued operations from the continuing operations of the Company since the Company will not have any significant continuing involvement in the operations after the sale. The financial position and results of operations of discontinued operations are presented as single line items on the consolidated balance sheets and statements of operations, respectively.
	PREMIUMS AND RELATED EXPENSES
	Premiums are recognized as income, net of any applicable reinsurance or retrocessional coverage purchased, over the terms of the related contracts and policies. Premiums written are based on contract and policy terms and include estimates based on information received from both insureds and ceding companies. Subsequent differences arising on such estimates are recorded in the period in which they are determined. Unearned premiums represents the portion of premiums written that relate to the unexpired terms of contracts and policies in force. Amounts are computed by pro rata methods based on statistical data or reports received from ceding companies. Reinstatement premiums are estimated after the occurrence of a significant loss and are recorded in accordance with the contract terms based upon paid losses and case reserves. Reinstatement premiums are earned when written.
	Acquisition costs are incurred when a contract or policy is issued and only the costs directly related to the successful acquisition of new and renewal contract or policies are deferred and amortized over the same period in which the related premiums are earned. Acquisition costs are shown net of commissions and profit commissions earned on ceded reinsurance, and consist principally of commissions, brokerage and premium tax expenses incurred at the time a contract or policy is issued. Deferred policy acquisition costs are limited to their estimated realizable value based on the related unearned premiums. Anticipated claims and claim expenses, based on historical and current experience, and anticipated investment income related to those premiums are considered in determining the recoverability of deferred acquisition costs.
	CLAIMS AND CLAIM EXPENSES
	The reserve for claims and claim expenses includes estimates for unpaid claims and claim expenses on reported losses as well as an estimate of losses incurred but not reported. The reserve is based on individual claims, case reserves and other reserve estimates reported by insureds and ceding companies as well as management estimates of ultimate losses. Inherent in the estimates of ultimate losses are expected trends in claim severity and frequency and other factors which could vary significantly as claims are settled. Also, during the past few years, the Company has increased its specialty reinsurance business, but does not have the benefit of a significant amount of its own historical experience in certain of these lines of business. Accordingly, the setting and reserving for incurred losses in these lines of business could be subject to greater variability.
	Ultimate losses may vary materially from the amounts provided in the consolidated financial statements. These estimates are reviewed regularly and, as experience develops and new information becomes known, the reserves are adjusted as necessary. Such adjustments, if any, are reflected in the consolidated statements of operations in the period in which they become known and are accounted for as changes in estimates.
	REINSURANCE
	Amounts recoverable from reinsurers are estimated in a manner consistent with the claim liability associated with the reinsured policies. For multi-year retrospectively rated contracts, the Company accrues amounts (either assets or liabilities) that are due to or from assuming companies based on estimated contract experience. If the Company determines that adjustments to earlier estimates are appropriate, such adjustments are recorded in the period in which they are determined. Reinsurance recoverables on dual trigger reinsurance contracts require the Company to estimate its ultimate losses applicable to these contracts as well as estimate the ultimate amount of insured industry losses that will be reported by the applicable statistical reporting agency, as per the contract terms. Amounts recoverable from reinsurers are recorded net of a valuation allowance for estimated uncollectible recoveries.
	Assumed and ceded reinsurance contracts that lack a significant transfer of risk are treated as deposits.
	Certain assumed and ceded reinsurance contracts that do not meet all of the criteria to be accounted for as reinsurance in accordance with FASB ASC Topic Financial Services - Insurance have been accounted for at fair value under the fair value option in accordance with FASB ASC Topic Financial Instruments.
	INVESTMENTS, CASH AND CASH EQUIVALENTS
	Fixed Maturity Investments
	Investments in fixed maturities are classified as available for sale or trading and are reported at fair value. Investment transactions are recorded on the trade date with balances pending settlement reflected in the balance sheet as a receivable for investments sold or a payable for investments purchased. Net investment income includes interest and dividend income together with amortization of market premiums and discounts and is net of investment management and custody fees. The amortization of premium and accretion of discount for fixed maturity securities is computed using the effective yield method. For mortgage-backed securities and other holdings for which there is prepayment risk, prepayment assumptions are evaluated quarterly and revised as necessary. Any adjustments required due to the change in effective yields and maturities are recognized on a prospective basis through yield adjustments. Fair values of investments are based on quoted market prices, or when such prices are not available, by reference to broker or underwriter bid indications and/or internal pricing valuation techniques. The net unrealized appreciation or depreciation on fixed maturity investments available for sale is included in accumulated other comprehensive income. The net unrealized appreciation or depreciation on fixed maturity investments trading is included in net realized and unrealized gains on investments in the consolidated statements of operations. Realized gains or losses on the sale of investments are determined on the basis of the first in first out cost method and, for fixed maturity investments available for sale, include adjustments to the cost basis of investments for declines in value that are considered to be other-than-temporary.
	Other-Than-Temporary Impairments
	The Company recognizes other-than-temporary impairments in earnings for its impaired fixed maturity securities available for sale (i) for which the Company has the intent to sell the security or (ii) it is more likely than not that the Company will be required to sell the debt security before its anticipated recovery and (iii) for those securities which have a credit loss. In assessing whether a credit loss exists, the Company compares the present value of the cash flows expected to be collected from the security with the amortized cost basis of the security. In instances in which a determination is made that an impairment exists but the Company does not intend to sell the security and it is not more likely than not that the Company will be required to sell the security before the anticipated recovery of its remaining amortized cost basis, the impairment is separated into (i) the amount of the total impairment related to the credit loss and (ii) the amount of the total impairment related to all other factors. The amount of the total other-than-temporary impairment related to the credit loss is recognized in earnings. The amount of the total other-than-temporary impairment related to all other factors is recognized in other comprehensive income. In periods after the recognition of other-than-temporary impairments on the Company’s fixed maturity securities available for sale, the Company accounts for such securities as if they had been purchased on the measurement date of the other-than-temporary impairment at an amortized cost basis equal to the previous amortized cost basis less the other-than-temporary impairment recognized in earnings. For debt securities in which other-than-temporary impairments were recognized in earnings, the difference between the new amortized cost basis and the cash flows expected to be collected will be amortized into net investment income.
	Short Term Investments
	Short term investments, which are managed as part of the Company’s investment portfolio and have a maturity of one year or less when purchased, are carried at amortized cost, which approximates fair value. The net unrealized appreciation or depreciation on short term investments is included in net realized and unrealized gains on investments in the consolidated statements of operations.
	Equity Investments, Classified as Trading
	Equity investments are accounted for at fair value in accordance with FASB ASC Topic Financial Instruments. Fair values are primarily priced by pricing services, reflecting the closing price quoted for the final trading day of the period. Net investment income includes dividend income and the net realized and unrealized appreciation or depreciation on equity investments is included in net realized and unrealized gains on investments in the consolidated statements of operations.
	Other Investments
	The Company accounts for its other investments at fair value in accordance with FASB ASC Topic Financial Instruments. The fair value of certain of the Company’s fund investments, which principally include private equity funds, a senior secured bank loan fund and hedge funds, is recorded on its balance sheet in other investments, and is generally established on the basis of the net valuation criteria established by the managers of such investments, if applicable. The net valuation criteria established by the managers of such investments is established in accordance with the governing documents of such investments. Certain of the Company’s fund managers, fund administrators, or both, are unable to provide final fund valuations as of the Company’s current reporting date. The typical reporting lag experienced by the Company to receive a final net asset value report is one month for hedge funds and senior secured bank loan funds and three months for private equity funds, although, in the past, in respect of certain of the Company’s private equity funds, the Company has on occasion experienced delays of up to six months at year end, as the private equity funds typically complete their respective year-end audits before releasing their final net asset value statements.
	In circumstances where there is a reporting lag between the current period end reporting date and the reporting date of the latest fund valuation, the Company estimates the fair value of these funds by starting with the prior month or quarter-end fund valuations, adjusting these valuations for actual capital calls, redemptions or distributions, as well as the impact of changes in foreign currency exchange rates, and then estimating the return for the current period. In circumstances in which the Company estimates the return for the current period, all information available to the Company is utilized. This principally includes preliminary estimates reported to the Company by its fund managers, obtaining the valuation of underlying portfolio investments where such underlying investments are publicly traded and therefore have a readily observable price, using information that is available to the Company with respect to the underlying investments, reviewing various indices for similar investments or asset classes, as well as estimating returns based on the results of similar types of investments for which the Company has obtained reported results, or other valuation methods, where possible. Actual final fund valuations may differ, perhaps materially so, from the Company’s estimates and these differences are recorded in the Company’s statement of operations in the period in which they are reported to the Company as a change in estimate.
	The Company’s other investments also include investments in catastrophe bonds which are recorded at fair value and based on broker or underwriter bid indications.
	Investments in Other Ventures
	Investments in which the Company has significant influence over the operating and financial policies of the investee are classified as investments in other ventures, under equity method, and are accounted for under the equity method of accounting. Under this method, the Company records its proportionate share of income or loss from such investments in its results for the period. Any decline in value of investments in other ventures, under equity method considered by management to be other-than-temporary is charged to income in the period in which it is determined.
	Cash and Cash Equivalents
	Cash equivalents include money market instruments with a maturity of ninety days or less when purchased.
	STOCK INCENTIVE COMPENSATION
	The Company is authorized to issue restricted stock awards and units, performance shares, stock options and other equity-based awards to its employees and directors. The fair value of the compensation cost is measured at the grant date and expensed over the period for which the employee is required to provide services in exchange for the award.
	In addition, the Company is authorized to issue cash settled restricted stock units (“CSRSU”) to its employees. The fair value of CSRSUs is determined at each reporting date using observable exchange traded prices for the Company’s common shares and is expensed over the period for which the employee is required to provide service in exchange for the award. In addition, the fair value of the award is recorded on the Company’s consolidated balance sheet as a liability as it is expensed and until the point payment is made to the employee.
	Forfeiture benefits are estimated on a quarterly basis and incorporated in the determination of stock-based compensation.
	DERIVATIVES
	The Company enters into derivative instruments such as futures, options, swaps, forward contracts and other derivative contracts in order to manage its foreign currency exposure, obtain exposure to a particular financial market, for yield enhancement, or for trading and speculation. The Company accounts for its derivatives in accordance with FASB ASC Topic Derivatives and Hedging, which requires all derivatives to be recorded at fair value on the Company’s balance sheet as either assets or liabilities, depending on their rights or obligations, with changes in fair value reflected in current earnings. The Company does not currently apply hedge accounting. The fair value of the Company’s derivatives is estimated by reference to quoted prices or broker quotes, where available, or in the absence of quoted prices or broker quotes, the use of industry or internal valuation models.
	FAIR VALUE
	The Company accounts for certain of its assets and liabilities at fair value in accordance with FASB ASC Topic Fair Value Measurements and Disclosures.  The Company recognizes the change in unrealized gains and losses arising from changes in fair value in its statements of operations, with the exception of changes in unrealized gains and losses on its fixed maturity investments available for sale, which are recognized as a component of accumulated other comprehensive income (loss) in shareholders’ equity.
	BUSINESS COMBINATIONS, GOODWILL AND OTHER INTANGIBLE ASSETS
	The Company accounts for business combinations in accordance with FASB ASC Topic Business Combinations, and goodwill and other intangible assets that arise from business combinations in accordance with FASB ASC Topic Intangibles – Goodwill and Other. A purchase price that is in excess of the fair value of the net assets acquired arising from a business combination is recorded as goodwill, and is not amortized. Other intangible assets with a finite life are amortized over the estimated useful life of the asset. Other intangible assets with an indefinite useful life are not amortized.
	Goodwill and other indefinite life intangible assets are tested for impairment on an annual basis or more frequently if events or changes in circumstances indicate that the carrying amount may not be recoverable. Definite life intangible assets are reviewed for indicators of impairment on an annual basis or more frequently if events or changes in circumstances indicate that the carrying amount may not be recoverable, and tested for impairment if appropriate. For purposes of the annual impairment evaluation, goodwill is assigned to the applicable reporting unit of the acquired entities giving rise to the goodwill. Goodwill and other intangible assets recorded in connection with investments accounted for under the equity method, are recorded as “Investments in other ventures, under equity method” on the Company’s consolidated balance sheets.
	The Company has established the beginning of the fourth quarter as the date for performing its annual impairment tests. The Company has the option to first assess qualitative factors to determine whether it is necessary to perform the quantitative goodwill impairment test. Under this option, the Company would not be required to calculate the fair value of a reporting unit unless the Company determines, based on its qualitative assessment, that it is more likely than not that a reporting unit’s fair value is less than its carrying amount. If goodwill or other intangible assets are impaired, they are written down to their estimated fair value with a corresponding expense reflected in the Company’s consolidated statements of operations.
	NONCONTROLLING INTERESTS
	The Company accounts for noncontrolling interests in the shareholders’ equity section of the Company’s consolidated balance sheet in accordance with FASB ASC Topic Consolidations, and presents such noncontrolling shareholders’ interest in the net assets of the subsidiary. Net (income) loss attributable to noncontrolling interests is presented separately in the Company’s consolidated statements of operations.
	In addition, the Company accounts for redeemable noncontrolling interest in DaVinciRe in the mezzanine section of the Company’s consolidated balance sheet in accordance with United States Securities and Exchange Commission (“SEC”) guidance which is applicable to SEC registrants. The SEC guidance requires shares, not required to be accounted for in accordance with FASB ASC Topic Distinguishing Liabilities from Equity, and having redemption features that are not solely within the control of the issuer, to be classified outside of permanent equity in the mezzanine section of the balance sheet. Because the share classes related to the redeemable noncontrolling interest portion of DaVinciRe are not considered liabilities in accordance with FASB ASC Topic Distinguishing Liabilities from Equity and have redemption features that are not solely within the control of DaVinciRe, the redeemable noncontrolling interest in DaVinciRe is presented in the mezzanine section on the Company’s consolidated balance sheet in accordance with the SEC guidance noted above. The SEC guidance does not impact the accounting for redeemable noncontrolling interest on the consolidated statements of operations; therefore, the provisions of FASB ASC Topic Consolidation with respect to the consolidated statements of operations still apply.
	VARIABLE INTEREST ENTITIES
	The Company accounts for VIEs in accordance with FASB ASC Topic Consolidation, which requires the consolidation of all VIEs by the primary beneficiary, that being the investor that has the power to direct the activities of the VIE and that will absorb a majority of the VIE’s expected losses or residual returns. The Company determines whether it is the primary beneficiary of a VIE by performing an analysis that principally considers: (i) the VIE’s purpose and design, including the risks the VIE was designed to create and pass through to its variable interest holders; (ii) the VIE’s capital structure; (iii) the terms between the VIE and its variable interest holders and other parties involved with the VIE; (iv) which variable interest holders have the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance; (v) which variable interest holders have the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE; and (vi) related party relationships. The Company reassesses its initial determination of whether the Company is the primary beneficiary of a VIE upon changes in facts and circumstances that could potentially alter the Company’s assessment.
	EARNINGS PER SHARE
	The Company calculates earnings per share in accordance with FASB ASC Topic Earnings per Share. Basic earnings per share are based on weighted average common shares and exclude any dilutive effects of options and restricted stock. Diluted earnings per share assumes the exercise of all dilutive stock options and restricted stock grants.
	The two-class method is used to determine earnings per share based on dividends declared on common shares and participating securities (i.e., distributed earnings) and participation rights of participating securities in any undistributed earnings. Each unvested restricted share granted by the Company to its employees is considered a participating security and the Company uses the two-class method to calculate its net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – basic and diluted.
	FOREIGN EXCHANGE
	The Company’s functional currency is the U.S. dollar. Revenues and expenses denominated in foreign currencies are translated at the prevailing exchange rate at the transaction date. Monetary assets and liabilities denominated in foreign currencies are remeasured at exchange rates in effect at the balance sheet date, which may result in the recognition of exchange gains or losses which are included in the determination of net income (loss).
	TAXATION
	Income taxes have been provided in accordance with the provisions of FASB ASC Topic Income Taxes. Deferred tax assets and liabilities result from temporary differences between the amounts recorded in the consolidated financial statements and the tax basis of the Company’s assets and liabilities. Such temporary differences are primarily due to net operating loss carryforwards and GAAP versus tax basis accounting differences relating to interest expense, underwriting results, accrued expenses and investments. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance against deferred tax assets is recorded if it is more likely than not that all, or some portion, of the benefits related to deferred tax assets will not be realized.
	Uncertain tax positions are also accounted for in accordance with FASB ASC Topic Income Taxes.  Uncertain tax positions must meet a more likely than not recognition threshold to be recognized.
	RECENTLY ADOPTED ACCOUNTING PRONOUNCEMENTS
	Pushdown Accounting, a consensus of the FASB Emerging Issues Task Force
	In November 2014, the FASB issued ASU No. 2014-17, Pushdown Accounting, a consensus of the FASB Emerging Issues Task Force (“ASU 2014-17”). The objective of ASU 2014-17 is to provide guidance on whether and at what threshold an acquired entity that is a business or nonprofit activity can apply pushdown accounting in its separate financial statements. The amendments in ASU 2014-17 apply to the separate financial statements of an acquired entity and its subsidiaries that are a business or nonprofit activity (either public or nonpublic) upon the occurrence of an event in which an acquirer (an individual or an entity) obtains control of the acquired entity. The amendments in ASU 2014-17 provide an acquired entity with an option to apply pushdown accounting in its separate financial statements upon occurrence of an event in which an acquirer obtains control of the acquired entity. The amendments in ASU 2014-17 became effective on November 18, 2014. After the effective date, an acquired entity can make an election to apply the guidance to future change-in-control events or to its most recent change-in-control event. However, if the financial statements for the period in which the most recent change-in-control event occurred already have been issued or made available to be issued, the application of this guidance would be a change in accounting principle. The Company is currently evaluating the impact of this guidance on its consolidated statements of operations and financial position, specifically as it relates to the contemplated Merger with Platinum. Refer to “Note 20. Commitments, Contingencies and Other Items”, for more information with respect to the Merger.
	Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists
In July 2013, the FASB issued ASU No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (“ASU 2013-11”). The objective of ASU 2013-11 is to improve the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. ASU 2013-11 seeks to reduce the diversity in practice by providing guidance on the presentation of unrecognized tax benefits to better reflect the manner in which an entity would settle at the reporting date any additional income taxes that would result from the disallowance of a tax position when net operating loss carryforwards, similar tax losses, or tax credit carryforwards exist. ASU 2013-11 became effective for annual and interim reporting periods beginning after December 15, 2013. The Company prospectively adopted ASU 2013-11 effective January 1, 2014 and the adoption of this guidance did not have a material impact on the Company’s consolidated statements of operations and financial position.
Financial Services - Investment Companies (Topic 946) Amendments to the Scope, Measurement, and Disclosure Requirements
In June 2013, the FASB issued ASU No. 2013-08, Amendments to the Scope, Measurement, and Disclosure Requirements (“ASU 2013-08”). The objective of ASU 2013-08 is to change the approach to the investment company assessment, clarify the characteristics of an investment company and provide comprehensive guidance for assessing whether an entity is an investment company. In addition, ASU 2013-08 will require an investment company to measure noncontrolling ownership interests in other investment companies at fair value rather than using the equity method of accounting and require the following additional disclosures: (a) the fact that the entity is an investment company and is applying the guidance, (b) information about changes, if any, in an entity’s status as an investment company, and (c) information about financial support provided or contractually required to be provided by an investment company to any of its investees. ASU 2013-08 became effective for annual and interim reporting periods beginning after December 15, 2013. The Company prospectively adopted ASU 2013-08 effective January 1, 2014 and the adoption of this guidance did not have a material impact on the Company’s consolidated statements of operations and financial position.
RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS NOT YET ADOPTED
Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity
In April 2014, the FASB issued ASU No. 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity (“ASU 2014-08”). The objective of ASU 2014-08 is to improve the definition of discontinued operations by limiting discontinued operations reporting to disposals of components of an entity that represent strategic shifts that have (or will have) a major effect on an entity’s operations and financial results. ASU 2014-08 will also require expanded disclosures for discontinued operations and require an entity to disclose the pretax profit or loss of an individually significant component of an entity that does not qualify for discontinued operations reporting. ASU 2014-08 is prospectively effective for public business entities in annual periods beginning on or after December 15, 2014, and interim periods beginning on or after December 15, 2015. Entities may early adopt ASU 2014-08 for new disposals that have not been reported in the consolidated financial statements previously issued or available for issuance. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position.
Revenue from Contracts with Customers
In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). ASU 2014-09 provides comprehensive guidance on the recognition of revenue from customers arising from the transfer of goods and services. 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. ASU 2014-09 also provides guidance on accounting for certain contract costs and will also require new disclosures. ASU 2014-09 is effective for public business entities in annual and interim periods beginning after December 15, 2016. Early adoption is permitted. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position.
Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period
In June 2014, the FASB Issued ASU No. 2014-12, Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period (“ASU 2014-12”). The objective of ASU 2014-12 is to resolve the diverse accounting treatment of share-based payment awards in situations where an employee would be eligible to vest in the award regardless of whether the employee is rendering service on the date the performance target is achieved. For example, if an employee is eligible to retire or otherwise terminate employment before the end of the period in which a performance target could be achieved and still be eligible to vest in the award. ASU 2014-12 will resolve if and when the performance target is achieved. ASU 2014-12 is effective for all entities in annual and interim periods beginning after December 15, 2014, with early adoption permitted. Entities may apply the amendments in ASU 2014-12 either (a) prospectively to all awards granted or modified after the effective date or (b) retrospectively to all awards with performance targets that are outstanding as of the beginning of the earliest annual period presented in the financial statements and to all new or modified awards thereafter. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position.

Discontinued_Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	DISCONTINUED OPERATIONS
	REAL
	On August 30, 2013, the Company entered into a purchase agreement with Munich to sell REAL and, on October 1, 2013, the Company closed the sale of REAL to Munich. In the third quarter of 2013, the Company classified the assets and liabilities associated with this transaction as held for sale and the financial results are reflected in the Company’s consolidated financial statements as “discontinued operations.”
	Consideration for the transaction was $60.0 million, paid in cash at closing, subject to post-closing adjustments for certain tax and other items. The Company recorded a loss on sale of $8.8 million in conjunction with the sale, including related direct expenses.
	U.S.-Based Insurance Operations
	On November 18, 2010, RenaissanceRe entered into a Stock Purchase Agreement with QBE Holdings, Inc. (“QBE”) to sell substantially all of its U.S.-based insurance operations, including its U.S. property and casualty business underwritten through managing general agents, its crop insurance business underwritten through Agro National, its commercial property insurance operations and its claims operations.  At December 31, 2010, the Company classified the assets and liabilities associated with this transaction as held for sale and the assets and liabilities were recorded at the lower of the carrying value or fair value less costs to sell. The financial results for these operations have been presented as discontinued operations in the Company’s consolidated statements of operations for all periods presented.
	Consideration for the transaction was book value at December 31, 2010, for the aforementioned businesses, payable in cash at closing and subject to adjustment for certain tax and other items.
	The transaction closed on March 4, 2011 and net consideration of $269.5 million was received by RenaissanceRe.
	Pursuant to the stock purchase agreement, RenaissanceRe’s U.S.-based insurance operations were subject to a post-closing review following December 31, 2011 of the net reserve for claims and claim expenses for loss events occurring on or prior to December 31, 2010 (the “Reserve Collar”). Effective May 23, 2012, RenaissanceRe and QBE reached an agreement in respect of the Reserve Collar, and RenaissanceRe paid QBE the sum of $9.0 million on June 1, 2012, representing full and final settlement of the Reserve Collar.
	Except as explicitly described as held for sale or as discontinued operations, and unless otherwise noted, all discussions and amounts presented herein relate to the Company’s continuing operations. All prior periods presented have been reclassified to conform to this form of presentation.
	The Company did not have any assets, liabilities or shareholders’ equity of discontinued operations held for sale related to REAL or the Company’s former U.S.-based insurance operations at December 31, 2014 or 2013.
	The Company did not have any income (loss) from discontinued operations held for sale for the year ended December 31, 2014. Details of the income (loss) from discontinued operations for the years ended December 31, 2013 and 2012 are as follows:
		Year ended December 31, 2013	REAL
		Revenues
		Net investment income	$	1,150
		Net foreign exchange gains	849
		Other income	701
		Net realized and unrealized losses on investments	(18		)
		Total revenues	2,682
		Expenses
		Operational expenses	89
		Corporate expenses	104
		Total expenses	193
		Income before taxes	2,489
		Income tax expense	(67		)
		Income from discontinued operations	$	2,422
		Year ended December 31, 2012	REAL			U.S.-based insurance operations			Total
		Revenues
		Net investment income	$	2,517		$	—		$	2,517
		Net foreign exchange losses	(96		)	—			(96		)
		Other (loss) income	(20,785		)	2,730			(18,055		)
		Net realized and unrealized gains on investments	3			—			3
		Total revenues	(18,361		)	2,730			(15,631		)
		Expenses
		Operational expenses	150			436			586
		Corporate expenses	236			—			236
		Total expenses	386			436			822
		(Loss) income before taxes	(18,747		)	2,294			(16,453		)
		Income tax expense	(16		)	(7		)	(23		)
		(Loss) income from discontinued operations	$	(18,763	)	$	2,287		$	(16,476	)

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	GOODWILL AND OTHER INTANGIBLE ASSETS
	The following table shows an analysis of goodwill and other intangible assets:
			Goodwill and other intangible assets
			Goodwill			Other intangible assets			Total
		Balance as of December 31, 2012
		Gross amount	$	8,160		$	12,999		$	21,159
		Accumulated impairment losses and amortization	(2,299		)	(10,374		)	(12,673		)
			5,861			2,625			8,486
		Amortization	—			(375		)	(375		)
		Balance as of December 31, 2013
		Gross amount	8,160			12,999			21,159
		Accumulated impairment losses and amortization	(2,299		)	(10,749		)	(13,048		)
			5,861			2,250			8,111
		Amortization	—			(209		)	(209		)
		Balance as of December 31, 2014
		Gross amount	8,160			12,999			21,159
		Accumulated impairment losses and amortization	(2,299		)	(10,958		)	(13,257		)
			$	5,861		$	2,041		$	7,902
	The following table shows an analysis of goodwill and other intangible assets included in investments in other ventures, under equity method:
			Goodwill and other intangible assets included
			in investments in other  ventures, under equity method
			Goodwill			Other intangible  assets			Total
		Balance as of December 31, 2012
		Gross amount	$	10,840		$	44,323		$	55,163
		Accumulated impairment losses and amortization	—			(24,769		)	(24,769		)
			10,840			19,554			30,394
		Acquired during the year	1,705			1,155			2,860
		Amortization	—			(4,042		)	(4,042		)
		Balance as of December 31, 2013
		Gross amount	12,545			45,478			58,023
		Accumulated impairment losses and amortization	—			(28,811		)	(28,811		)
			12,545			16,667			29,212
		Adjustments to gross amount	(227		)	(78		)	(305		)
		Amortization	—			(3,655		)	(3,655		)
		Balance as of December 31, 2014
		Gross amount	12,318			45,400			57,718
		Accumulated impairment losses and amortization	—			(32,466		)	(32,466		)
			$	12,318		$	12,934		$	25,252
	The gross carrying value and accumulated amortization by major category of other intangible assets is shown below:
			Other intangible assets
		At December 31, 2014	Gross			Accumulated			Total
			carrying			amortization and impairment losses
			value
		Customer relationships and customer lists	$	40,562		$	(28,057	)	$	12,505
		Lloyd’s managing agency license	1,867			—			1,867
		Trademarks and trade names	610			(159		)	451
		Covenants not-to-compete	2,130			(1,978		)	152
		Software	8,730			(8,730		)	—
		Patents and intellectual property	4,500			(4,500		)	—
			$	58,399		$	(43,424	)	$	14,975
			Other intangible assets
		At December 31, 2013	Gross			Accumulated			Total
			carrying			amortization and impairment losses
			value
		Customer relationships and customer lists	$	40,640		$	(24,522	)	$	16,118
		Lloyd’s managing agency license	1,867			—			1,867
		Covenants not-to-compete	2,130			(1,674		)	456
		Trademarks and trade names	610			(134		)	476
		Software	8,730			(8,730		)	—
		Patents and intellectual property	4,500			(4,500		)	—
			$	58,477		$	(39,560	)	$	18,917
	The useful life of intangible assets with finite lives ranges from one to 25 years, with a weighted-average amortization period of 11 years. Expected amortization of the other intangible assets, including other intangible assets recorded in investments in other ventures, under equity method, is shown below:
			Other			Other			Total
			intangibles			intangible
			assets
			included
			in investments
			in other
			ventures, under
			equity method
	2015	$	174		$	2,991		$	3,165
	2016	—			2,292			2,292
	2017	—			1,914			1,914
	2018	—			1,484			1,484
	2019	—			1,041			1,041
	2020 and thereafter	—			3,212			3,212
	Total remaining amortization expense	$	174		$	12,934		$	13,108
	Indefinite lived	1,867			—			1,867
	Total	$	2,041		$	12,934		$	14,975

Investments

Investments	12 Months Ended
	Dec. 31, 2014
Investments [Abstract]
Investments	INVESTMENTS
	Fixed Maturity Investments Trading
	The following table summarizes the fair value of fixed maturity investments trading:
			December 31,			December 31,
			2014			2013
		U.S. treasuries	$	1,671,471		$	1,352,413
		Agencies	96,208			186,050
		Non-U.S. government (Sovereign debt)	280,651			334,580
		Non-U.S. government-backed corporate	146,467			237,479
		Corporate	1,610,442			1,803,415
		Agency mortgage-backed	312,333			336,661
		Non-agency mortgage-backed	241,590			243,795
		Commercial mortgage-backed	373,117			303,214
		Asset-backed	24,406			11,429
		Total fixed maturity investments trading	$	4,756,685		$	4,809,036
	Fixed Maturity Investments Available For Sale
	The following table summarizes the amortized cost, fair value and related unrealized gains and losses and non-credit other-than-temporary impairments of fixed maturity investments available for sale:
						Included in Accumulated
						Other Comprehensive Income
		At December 31, 2014	Amortized			Gross				Gross				Fair Value				Non-Credit
			Cost			Unrealized				Unrealized								Other-Than-
						Gains				Losses								Temporary
																		Impairments
																		(1)
		Agency mortgage-backed	$	3,928		$	359			$	—			$	4,287			$	—
		Non-agency mortgage-backed	9,478			1,985				(3		)		11,460				656
		Commercial mortgage-backed	7,291			643				—				7,934				—
		Asset-backed	3,075			129				—				3,204				—
		Total fixed maturity investments available for sale	$	23,772		$	3,116			$	(3	)		$	26,885			$	656
						Included in Accumulated
						Other Comprehensive Income
		At December 31, 2013	Amortized Cost			Gross				Gross				Fair Value				Non-Credit
						Unrealized				Unrealized								Other-Than-
						Gains				Losses								Temporary
																		Impairments
																		(1)
		Agency mortgage-backed	$	4,880		$	378			$	(11	)		$	5,247			$	—
		Non-agency mortgage-backed	11,735			2,414				(6		)		14,143				(742		)
		Commercial mortgage-backed	10,052			970				—				11,022				—
		Asset-backed	3,606			223				—				3,829				—
		Total fixed maturity investments available for sale	$	30,273		$	3,985			$	(17	)		$	34,241			$	(742	)
	-1	Represents the non-credit component of other-than-temporary impairments recognized in accumulated other comprehensive income adjusted for subsequent sales of securities. It does not include the change in fair value subsequent to the impairment measurement date.
	Contractual maturities of fixed maturity investments are described in the following table. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
			Trading							Available for Sale								Total Fixed Maturity Investments
		At December 31, 2014	Amortized			Fair Value				Amortized Cost				Fair Value				Amortized Cost				Fair Value
			Cost
		Due in less than one year	$	153,250		$	151,803			$	—			$	—			$	153,250			$	151,803
		Due after one through five years	2,976,602			2,969,828				—				—				2,976,602				2,969,828
		Due after five through ten years	544,285			537,636				—				—				544,285				537,636
		Due after ten years	140,294			145,972				—				—				140,294				145,972
		Mortgage-backed	910,897			927,040				20,697				23,681				931,594				950,721
		Asset-backed	24,285			24,406				3,075				3,204				27,360				27,610
		Total	$	4,749,613		$	4,756,685			$	23,772			$	26,885			$	4,773,385			$	4,783,570
	Equity Investments Trading
	The following table summarizes the fair value of equity investments trading:
			December 31,			December 31,
			2014			2013
		Financials	$	222,190		$	152,905
		Communications and technology	31,376			4,300
		Industrial, utilities and energy	28,859			25,350
		Consumer	19,522			44,115
		Healthcare	16,582			15,340
		Basic materials	3,569			12,766
		Total	$	322,098		$	254,776
Pledged Investments
At December 31, 2014, $2,379.4 million of cash and investments at fair value were on deposit with, or in trust accounts for the benefit of, various counterparties, including with respect to the Company’s standby letter of credit facility and bilateral letter of credit facility (2013 - $2,081.1 million). Of this amount, $691.9 million is on deposit with, or in trust accounts for the benefit of, U.S. state regulatory authorities (2013 - $652.8 million).
Reverse Repurchase Agreements
At December 31, 2014, the Company held $49.3 million (2013 - $37.3 million) of reverse repurchase agreements. These loans are fully collateralized, are generally outstanding for a short period of time and are presented on a gross basis as part of short term investments on the Company’s consolidated balance sheets. The required collateral for these loans typically include high-quality, readily marketable instruments at a minimum amount of 102% of the loan principal. Upon maturity, the Company receives principal and interest income.
Net Investment Income, Net Realized and Unrealized Gains on Investments and Net Other-Than-Temporary Impairments
The components of net investment income are as follows:
	Year ended December 31,	2014			2013				2012
	Fixed maturity investments	$	100,855		$	95,907			$	103,330
	Short term investments	944			1,698				1,007
	Equity investments	3,450			2,295				1,086
	Other investments
	Hedge funds and private equity investments	18,867			45,810				36,635
	Other	11,144			73,692				35,196
	Cash and cash equivalents	395			191				277
		135,655			219,593				177,531
	Investment expenses	(11,339		)	(11,565		)		(11,806		)
	Net investment income	$	124,316		$	208,028			$	165,725
Net realized and unrealized gains on investments and net other-than-temporary impairments are as follows:
	Year ended December 31,	2014			2013				2012
	Gross realized gains	$	45,568		$	72,492			$	97,787
	Gross realized losses	(14,868		)	(50,206		)		(16,705		)
	Net realized gains on fixed maturity investments	30,700			22,286				81,082
	Net unrealized gains (losses) on fixed maturity investments trading	19,680			(87,827		)		75,279
	Net realized and unrealized (losses) gains on investments-related derivatives	(30,931		)	31,058				(866		)
	Net realized gains on equity investments trading	10,908			26,650				—
	Net unrealized gains on equity investments trading	11,076			42,909				7,626
	Net realized and unrealized gains on investments	$	41,433		$	35,076			$	163,121
	Total other-than-temporary impairments	$	—		$	—			$	(395	)
	Portion recognized in other comprehensive income, before taxes	—			—				52
	Net other-than-temporary impairments	$	—		$	—			$	(343	)
The following table provides an analysis of the components of other comprehensive income and reclassifications out of accumulated other comprehensive income.
		Year ended December 31, 2014
		Investments in other ventures			Fixed maturity investments available for sale				Total
	Beginning balance	$	163		$	3,968			$	4,131
	Other comprehensive income (loss) before reclassifications	140			(855		)		(715		)
	Amounts reclassified from accumulated other comprehensive income by statement of operations line item:
	Realized gains reclassified from accumulated other comprehensive income to net realized and unrealized gains (losses) on investments	—			—				—
	Net current-period other comprehensive income (loss)	140			(855		)		(715		)
	Ending balance	$	303		$	3,113			$	3,416
		Year ended December 31, 2013
		Investments in other ventures			Fixed maturity investments available for sale				Total
	Beginning balance	$	1,625		$	11,997			$	13,622
	Other comprehensive loss before reclassifications	(1,462		)	(481		)		(1,943		)
	Amounts reclassified from accumulated other comprehensive income by statement of operations line item:
	Realized gains reclassified from accumulated other comprehensive income to net realized and unrealized gains (losses) on investments	—			(7,548		)		(7,548		)
	Net current-period other comprehensive loss	(1,462		)	(8,029		)		(9,491		)
	Ending balance	$	163		$	3,968			$	4,131
The following tables provide an analysis of the length of time the Company’s fixed maturity investments available for sale in an unrealized loss have been in a continual unrealized loss position.
		Less than 12 Months							12 Months or Greater								Total
	At December 31, 2014	Fair Value			Unrealized				Fair Value				Unrealized				Fair Value				Unrealized
					Losses								Losses								Losses
	Non-agency mortgage-backed	$	—		$	—			$	69			$	(3	)		$	69			$	(3	)
	Total	$	—		$	—			$	69			$	(3	)		$	69			$	(3	)
		Less than 12 Months							12 Months or Greater								Total
	At December 31, 2013	Fair Value			Unrealized				Fair Value				Unrealized				Fair Value				Unrealized
					Losses								Losses								Losses
	Agency mortgage-backed	$	726		$	(11	)		$	—			$	—			$	726			$	(11	)
	Non-agency mortgage-backed	—			—				89				(6		)		89				(6		)
	Commercial mortgage-backed	39			—				—				—				39				—
	Total	$	765		$	(11	)		$	89			$	(6	)		$	854			$	(17	)
At December 31, 2014, the Company held two fixed maturity investments available for sale securities that were in an unrealized loss position (2013 - four), including two fixed maturity investments available for sale securities that were in an unrealized loss position for twelve months or greater (2013 - two). The Company does not intend to sell these securities and it is not more likely than not that the Company will be required to sell these securities before the anticipated recovery of the remaining amortized cost basis. The Company performed reviews of its fixed maturity investments available for sale for the years ended December 31, 2014 and 2013, respectively, in order to determine whether declines in the fair value below the amortized cost basis were considered other-than-temporary in accordance with the applicable guidance, as discussed below.
Other-Than-Temporary Impairment Process
The Company’s process for assessing whether declines in the fair value of its fixed maturity investments
available for sale represent impairments that are other-than-temporary includes reviewing each fixed
maturity investment available for sale that is impaired and determining: (i) if the Company has the intent to
sell the debt security or (ii) if it is more likely than not that the Company will be required to sell the debt
security before its anticipated recovery; and (iii) whether a credit loss exists, that is, where the Company
expects that the present value of the cash flows expected to be collected from the security is less than the
amortized cost basis of the security.
For the year ended December 31, 2014, the Company recognized $Nil of other-than-temporary impairments which were recognized in earnings and $Nil related to other factors which were recognized in other comprehensive income (2013 – $Nil and $Nil, respectively, 2012 - $0.3 million and $52 thousand, respectively).
The following table provides a rollforward of the amount of other-than-temporary impairments related to credit losses recognized in earnings for which a portion of an other-than-temporary impairment was recognized in accumulated other comprehensive income:
		2014			2013
	Balance – January 1	$	561		$	838
	Additions:
	Amount related to credit loss for which an other-than-temporary impairment was not previously recognized	—			—
	Amount related to credit loss for which an other-than-temporary impairment was previously recognized	—			—
	Reductions:
	Securities sold during the period	(63		)	(277		)
	Securities for which the amount previously recognized in other comprehensive income was recognized in earnings, because the Company intends to sell the security or is more likely than not the Company will be required to sell the security	—			—
	Increases in cash flows expected to be collected that are recognized over the remaining life of the security	—			—
	Balance – December 31	$	498		$	561
Other Investments
The table below shows the fair value of the Company’s portfolio of other investments:
	At December 31,	2014			2013
	Private equity partnerships	$	281,932		$	322,391
	Catastrophe bonds	200,329			229,016
	Senior secured bank loan funds	19,316			18,048
	Hedge funds	2,570			3,809
	Total other investments	$	504,147		$	573,264
Interest income, income distributions and net realized and unrealized gains on other investments are included in net investment income and totaled $30.0 million (2013 – $119.5 million, 2012 – $71.8 million) of which $1.4 million was related to net unrealized losses (2013 – gains of $75.8 million, 2012 – gains of $38.2 million). Included in net investment income for the year ended December 31, 2014 is a loss of $0.6 million (2013 - $3.7 million, 2012 - $4.7 million) representing the change in estimate during the period related to the difference between the Company’s estimated fair value due to the lag in reporting, as discussed in “Note 2. Significant Accounting Policies”, and the actual amount as reported in the final net asset values provided by the Company’s fund managers.
The Company has committed capital to private equity partnerships and other entities of $623.8 million, of which $544.1 million has been contributed at December 31, 2014. The Company’s remaining commitments to these funds at December 31, 2014 totaled $84.0 million. In the future, the Company may enter into additional commitments in respect of private equity partnerships or individual portfolio company investment opportunities.
Investments in Other Ventures, under Equity Method
The table below shows the Company’s portfolio of investments in other ventures, under equity method:
		2014										2013
	At December 31,	Investment			Ownership %			Carrying  Value				Investment				Ownership %			Carrying  Value
	THIG	$	50,000		25	%		$	20,811			$	50,000			25	%		$	25,107
	Tower Hill	10,000			30.3	%		18,991				10,000				29.4	%		14,506
	Tower Hill Re	4,250			25	%		5,162				—				—	%		—
	Tower Hill Signature	500			25	%		5,692				500				25	%		2,515
	Total Tower Hill Companies	64,750						50,656				60,500							42,128
	Top Layer Re	65,375			50	%		60,911				65,375				50	%		50,500
	Angus	10,507			40.4	%		8,072				10,507				42.5	%		9,180
	Other	3,000			22	%		1,074				3,000				22	%		3,808
	Total investments in other ventures, under equity method	$	143,632					$	120,713			$	139,382						$	105,616
Included in the table above is the Company’s investment in Angus Partners LLC (“Angus”). On December 1, 2013, the Company increased its investment in Angus through the transactions described in “Note 10. Noncontrolling Interests”. As a result of these transactions, the Company has cumulatively invested $10.5 million in Angus, representing a 40.4% ownership interest at December 31, 2014.
On July 1, 2008, the Company invested $50.0 million in Tower Hill Insurance Group, LLC (“THIG”) representing a 25.0% equity ownership. Included in the purchase price was $40.0 million of other intangibles and $7.8 million of goodwill, which, in accordance with generally accepted accounting principles, are recorded as “Investments in other ventures, under equity method” rather than “Goodwill and other intangibles” on the Company’s consolidated balance sheet.
The Company originally invested $13.1 million in Top Layer Re, representing a 50.0% ownership. In December 2010, March 2011 and December 2011, primarily as a result of net claims and claim expenses incurred by Top Layer Re with respect to the September 2010, February 2011 New Zealand and Tohoku Earthquakes, respectively, the Company invested an additional $13.8 million, $20.5 million and $18.0 million, respectively, in Top Layer Re, maintaining the Company’s 50% ownership interest.
The table below shows the Company’s equity in earnings of other ventures, under equity method:
	Year ended December 31,	2014			2013				2012
	Tower Hill Companies	$	18,376		$	10,270			$	4,965
	Top Layer Re	10,411			13,836				20,792
	Angus	(1,402		)	(858		)		(2,519		)
	Other	(1,310		)	(54		)		—
	Total equity in earnings of other ventures	$	26,075		$	23,194			$	23,238
Undistributed earnings in the Company’s investments in other ventures, under equity method were $20.0 million at December 31, 2014 (2013 - $15.5 million). During 2014, the Company received $10.3 million of dividends from its investments in other ventures, under equity method (2013 – $9.9 million, 2012 – $9.9 million). Except for Top Layer Re, the equity in earnings of Tower Hill Insurance Group, LLC., Tower Hill Holdings, Inc. and Tower Hill Signature Insurance Holdings, Inc. (collectively, the “Tower Hill Companies”), Angus and the Company’s other category of investments in other ventures are reported one quarter in arrears.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS
	The use of fair value to measure certain assets and liabilities with resulting unrealized gains or losses is pervasive within the Company’s consolidated financial statements. Fair value is defined under accounting guidance currently applicable to the Company to be the price that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between open market participants at the measurement date. The Company recognizes the change in unrealized gains and losses arising from changes in fair value in its consolidated statements of operations, with the exception of changes in unrealized gains and losses on its fixed maturity investments available for sale, which are recognized as a component of accumulated other comprehensive income in shareholders’ equity.
	FASB ASC Topic Fair Value Measurements and Disclosures prescribes a fair value hierarchy that prioritizes the inputs to the respective valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to valuation techniques that use at least one significant input that is unobservable (Level 3). The three levels of the fair value hierarchy are described below:
	•	Fair values determined by Level 1 inputs utilize unadjusted quoted prices obtained from active markets for identical assets or liabilities for which the Company has access. The fair value is determined by multiplying the quoted price by the quantity held by the Company;
	•	Fair values determined by Level 2 inputs utilize inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar assets and liabilities in active markets, and inputs other than quoted prices that are observable for the asset or liability, such as interest rates and yield curves that are observable at commonly quoted intervals, broker quotes and certain pricing indices; and
	•	Level 3 inputs are based all or in part on significant unobservable inputs for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability. In these cases, significant management assumptions can be used to establish management’s best estimate of the assumptions used by other market participants in determining the fair value of the asset or liability.
	In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy within which the fair value measurement in its entirety falls has been determined based on the lowest level input that is significant to the fair value measurement of the asset or liability. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and the Company considers factors specific to the asset or liability.
	In order to determine if a market is active or inactive for a security, the Company considers a number of factors, including, but not limited to, the spread between what a seller is asking for a security and what a buyer is bidding for the same security, the volume of trading activity for the security in question, the price of the security compared to its par value (for fixed maturity investments), and other factors that may be indicative of market activity.
	Other than the transaction noted below, there have been no material changes in the Company’s valuation techniques, nor have there been any transfers between Level 1 and Level 2, or Level 2 and Level 3 during the period represented by these consolidated financial statements. As discussed in greater detail below, the Company transferred its investment in the common shares of Trupanion, Inc. (“Trupanion”), a company that provides insurance for a variety of veterinarian costs, from Level 3 to Level 1, effective July 18, 2014, the date on which Trupanion became a publicly traded company on the New York Stock Exchange (the “NYSE”). The fair value transferred from Level 3 to Level 1 was $24.6 million.
	Below is a summary of the assets and liabilities that are measured at fair value on a recurring basis and also represents the carrying amount on the Company’s consolidated balance sheets:
		At December 31, 2014	Total			Quoted			Significant			Significant
						Prices in Active			Other			Unobservable
						Markets for			Observable			Inputs
						Identical			Inputs			(Level 3)
						Assets			(Level 2)
						(Level 1)
		Fixed maturity investments
		U.S. treasuries	$	1,671,471		$	1,671,471		$	—		$	—
		Agencies	96,208			—			96,208			—
		Non-U.S. government (Sovereign debt)	280,651			—			280,651			—
		Non-U.S. government-backed corporate	146,467			—			146,467			—
		Corporate	1,610,442			—			1,594,782			15,660
		Agency mortgage-backed	316,620			—			316,620			—
		Non-agency mortgage-backed	253,050			—			253,050			—
		Commercial mortgage-backed	381,051			—			381,051			—
		Asset-backed	27,610			—			27,610			—
		Total fixed maturity investments	4,783,570			1,671,471			3,096,439			15,660
		Short term investments	1,013,222			—			1,013,222			—
		Equity investments trading	322,098			322,098			—			—
		Other investments
		Private equity partnerships	281,932			—			—			281,932
		Catastrophe bonds	200,329			—			200,329			—
		Senior secured bank loan fund	19,316			—			—			19,316
		Hedge funds	2,570			—			—			2,570
		Total other investments	504,147			—			200,329			303,818
		Other assets and (liabilities)
		Assumed and ceded (re)insurance contracts	(8,744		)	—			—			(8,744		)
		Derivatives (1)	6,345			(569		)	7,104			(190		)
		Other	(11,509		)	—			(11,509		)	—
		Total other assets and (liabilities)	(13,908		)	(569		)	(4,405		)	(8,934		)
			$	6,609,129		$	1,993,000		$	4,305,585		$	310,544
	-1	See “Note 19. Derivative Instruments” for additional information related to the fair value by type of contract, of derivatives entered into by the Company.
		At December 31, 2013	Total			Quoted			Significant			Significant
						Prices in Active			Other			Unobservable
						Markets for			Observable			Inputs
						Identical			Inputs			(Level 3)
						Assets			(Level 2)
						(Level 1)
		Fixed maturity investments
		U.S. treasuries	$	1,352,413		$	1,352,413		$	—		$	—
		Agencies	186,050			—			186,050			—
		Non-U.S. government (Sovereign debt)	334,580			—			334,580			—
		Non-U.S. government-backed corporate	237,479			—			237,479			—
		Corporate	1,803,415			—			1,775,835			27,580
		Agency mortgage-backed	341,908			—			341,908			—
		Non-agency mortgage-backed	257,938			—			257,938			—
		Commercial mortgage-backed	314,236			—			314,236			—
		Asset-backed	15,258			—			15,258			—
		Total fixed maturity investments	4,843,277			1,352,413			3,463,284			27,580
		Short term investments	1,044,779			—			1,044,779			—
		Equity investments trading	254,776			254,776			—			—
		Other investments
		Private equity partnerships	322,391			—			—			322,391
		Catastrophe bonds	229,016			—			229,016			—
	Senior secured bank loan funds	18,048			—			—			18,048
	Hedge funds	3,809			—			—			3,809
	Total other investments	573,264			—			229,016			344,248
	Other assets and (liabilities)
	Derivatives (1)	4,758			823			6,425			(2,490		)
	Other	(12,991		)	—			(12,991		)	—
	Total other assets and (liabilities)	(8,233		)	823			(6,566		)	(2,490		)
		$	6,707,863		$	1,608,012		$	4,730,513		$	369,338
(1) See “Note 19. Derivative Instruments” for additional information related to the fair value by type of contract, of derivatives entered into by the Company.
Level 1 and Level 2 Assets and Liabilities Measured at Fair Value
Fixed Maturity Investments
Fixed maturity investments included in Level 1 consist of the Company’s investments in U.S. treasuries. Fixed maturity investments included in Level 2 are agencies, non-U.S. government, non-U.S. government-backed corporate, corporate, agency mortgage-backed, non-agency mortgage-backed, commercial mortgage-backed and asset-backed.
The Company’s fixed maturity investments are primarily priced using pricing services, such as index providers and pricing vendors, as well as broker quotations. In general, the pricing vendors provide pricing 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. Observable inputs include benchmark yields, reported trades, broker-dealer quotes, issuer spreads, bids, offers, reference data and industry and economic events. Index pricing generally relies on market traders as the primary source for pricing, however models are also utilized to provide prices for all index eligible securities. The models use a variety of observable inputs such as benchmark yields, transactional data, dealer runs, broker-dealer quotes and corporate actions. 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. treasuries
Level 1 - At December 31, 2014, the Company’s U.S. treasuries fixed maturity investments are primarily priced by pricing services and had a weighted average effective yield of 1.0% and a weighted average credit quality of AA (2013 - 0.8% and AA, respectively). When pricing these securities, the pricing services utilize daily data from many real time market sources, including active broker dealers. Certain data sources are regularly reviewed for accuracy to attempt to ensure the most reliable price source is used for each issue and maturity date.
Agencies
Level 2 - At December 31, 2014, the Company’s agency fixed maturity investments had a weighted average effective yield of 1.2% and a weighted average credit quality of AA (2013 - 1.3% and AA, respectively). The issuers of the Company’s agency fixed maturity investments primarily consist of the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation and other agencies. Fixed maturity investments included in agencies 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 (Sovereign debt)
Level 2 - Non-U.S. government fixed maturity investments held by the Company at December 31, 2014, had a weighted average effective yield of 1.1% and a weighted average credit quality of AA (2013 - 1.3% and AA, respectively). The issuers of securities in this sector are non-U.S. governments and their respective agencies as well as supranational organizations. Securities held in these sectors are primarily priced by pricing services that 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.
Non-U.S. government-backed corporate
Level 2 - Non-U.S. government-backed corporate fixed maturity investments had a weighted average effective yield of 1.1% and a weighted average credit quality of AAA at December 31, 2014 (2013 - 1.1% and AAA, respectively). Non-U.S. government-backed fixed maturity investments are primarily priced by pricing services that 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 to the respective curve 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.
Corporate
Level 2 - At December 31, 2014, the Company’s corporate fixed maturity investments principally consist of U.S. and international corporations and had a weighted average effective yield of 3.2% and a weighted average credit quality of BBB (2013 - 2.7% and BBB, respectively). 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.
Agency mortgage-backed
Level 2 - At December 31, 2014, the Company’s agency mortgage-backed fixed maturity investments included agency residential mortgage-backed securities with a weighted average effective yield of 2.3%, a weighted average credit quality of AA and a weighted average life of 5.6 years (2013 - 2.9%, AA and 6.2 years, respectively). The Company’s agency mortgage-backed fixed maturity investments are primarily priced by pricing services using a mortgage pool specific model which utilizes daily inputs from the active to be announced 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 mortgage-backed
Level 2 - The Company’s non-agency mortgage-backed fixed maturity investments include non-agency prime residential mortgage-backed and non-agency Alt-A fixed maturity investments. The Company has no fixed maturity investments classified as sub-prime held in its fixed maturity investments portfolio. At December 31, 2014, the Company’s non-agency prime residential mortgage-backed fixed maturity investments have a weighted average effective yield of 3.4%, a weighted average credit quality of non-investment grade, and a weighted average life of 4.1 years (2013 - 3.7%, BBB and 4.4 years, respectively). The Company’s non-agency Alt-A fixed maturity investments held at December 31, 2014 have a weighted average effective yield of 4.3%, a weighted average credit quality of BBB and a weighted average life of 5.0 years (2013 - 4.7%, non-investment grade and 4.0 years, respectively). Securities held in these sectors are primarily priced by pricing services using an option adjusted spread (“OAS”) 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.
Commercial mortgage-backed
Level 2 - The Company’s commercial mortgage-backed fixed maturity investments held at December 31, 2014 have a weighted average effective yield of 2.1%, a weighted average credit quality of AAA, and a weighted average life of 3.5 years (2013 - 2.1%, AA and 3.3 years, respectively). 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 discount the expected cash flows for each security held in this sector using a spread adjusted benchmark yield based on the characteristics of the security.
Asset-backed
Level 2 - At December 31, 2014, the Company’s asset-backed fixed maturity investments had a weighted average effective yield of 1.5%, a weighted average credit quality of AAA and a weighted average life of 2.5 years (2013 - 2.0%, AAA and 3.5 years, respectively). The underlying collateral for the Company’s asset-backed fixed maturity investments primarily consists of student loans, credit card receivables, auto loans and other receivables. 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.
Short Term Investments
Level 2 - The fair value of the Company’s portfolio of short term investments is generally determined using amortized cost which approximates fair value and, in certain cases, in a manner similar to the Company’s fixed maturity investments noted above.
Equity Investments, Classified as Trading
Level 1 - The fair value of the Company’s portfolio of equity investments, classified as trading is primarily priced by pricing services, reflecting the closing price quoted for the final trading day of the period. When pricing these securities, the pricing services utilize daily data from many real time market sources, including applicable securities exchanges. All data sources are regularly reviewed for accuracy to attempt to ensure the most reliable price source was used for each security.
At June 30, 2014, the Company had a corporate fixed maturity investment of $30.2 million in the convertible preferred equity of Trupanion, for which the Company measured the fair value using Level 3 inputs. On July 18, 2014, Trupanion common stock began publicly trading on the NYSE. Effective immediately prior to the closing of the IPO, the Company’s investment in the convertible preferred equity of Trupanion was converted into 2.5 million common shares of Trupanion. Trupanion common shares began publicly trading on the NYSE on July 18, 2014 at a share price of $10.00, resulting in a fair value of $24.6 million. Following the IPO, the Company transferred its investment in Trupanion from corporate fixed maturity investments to its portfolio of equity investments trading on its consolidated balance sheet and any realized and unrealized gains or losses related to Trupanion from the IPO price are included in net realized and unrealized gains (losses) on investments on the Company’s consolidated statements of operations. The Company has agreed, subject to certain exceptions, not to dispose of or hedge any of the common shares of Trupanion it held prior to January 14, 2015. Included in equity investments trading at December 31, 2014 is $17.1 million related to the Company’s investment in Trupanion.
At September 30, 2013, the Company had an investment of $48.0 million in the common shares of Essent Group Ltd., a then private U.S. mortgage guaranty insurance company which provides capital to lenders and investors that support financing for homeowner mortgages (“Essent”).  On October 31, 2013, Essent common shares began publicly trading on the NYSE at a share price of $17.00, resulting in a fair value of $85.6 million.  Following the initial public offering, the Company transferred its investment in Essent from other investments to its portfolio of equity investments trading on its consolidated balance sheet and any realized and unrealized gains or losses related to Essent from the initial public offering price are included in net realized and unrealized gains (losses) on investments on the Company’s consolidated statements of operations.  Included in equity investments trading at December 31, 2014 is $120.0 million related to the Company’s investment in Essent.
Other investments
Catastrophe bonds
Level 2 - The Company’s other investments include investments in catastrophe bonds which are recorded at fair value based on broker or underwriter bid indications.
Other assets and liabilities
Derivatives
Level 1 and Level 2 - Other assets and liabilities include certain derivatives entered into by the Company. The fair value of these transactions includes certain exchange traded foreign currency forward contracts which are considered Level 1, and certain credit derivatives, determined using standard industry valuation models and considered Level 2, as the inputs to the valuation model are based on observable market inputs, including credit spreads, credit ratings of the underlying referenced security, the risk free rate and the contract term.
Other
Level 2 - The liabilities measured at fair value and included in Level 2 at December 31, 2014 of $11.5 million are principally comprised of cash settled restricted stock units (“CSRSU”) that form part of the Company’s compensation program. The fair value of the Company’s CSRSUs is determined using observable exchange traded prices for the Company’s common shares.
Level 3 Assets and Liabilities Measured at Fair Value
Below is a summary of quantitative information regarding the significant observable and unobservable inputs (Level 3) used in determining the fair value of assets and liabilities measured at fair value on a recurring basis:
	December 31, 2014	Fair Value			Valuation Technique		Unobservable (U)	Low			High			Weighted Average or Actual
		(Level 3)					and Observable (O)
							Inputs
	Fixed maturity investments
	Corporate	$	15,660		Discounted cash flow (“DCF”)		Credit spread (U)	n/a			n/a			0.8		%
							Liquidity discount (U)	n/a			n/a			1		%
							Risk-free rate (O)	n/a			n/a			0.5		%
							Dividend rate (O)	n/a			n/a			6.5		%
	Total fixed maturity investments	15,660
	Other investments
	Private equity partnerships	281,932			Net asset valuation		Estimated performance (U)	(42.1		)%	17		%	0.1		%
	Senior secured bank loan fund	19,316			Net asset valuation		Estimated performance (U)	n/a			n/a			0.8		%
	Hedge funds	2,570			Net asset valuation		Estimated performance (U)	0		%	0		%	0		%
	Total other investments	303,818
	Other assets and (liabilities)
	Assumed and ceded (re)insurance contracts	(8,744		)	Internal valuation model		Net undiscounted cash flows (U)	$	160		$	8,006		$	2,528
							Contract period (O)	549			1,100			832
							Discount rate (U)	n/a			n/a			1.1		%
	Weather contract	(190		)	Internal valuation model		See below	n/a			n/a			See below
	Total other assets and (liabilities)	(8,934		)
		$	310,544
Fixed Maturity Investments
Corporate
Level 3 - Included in the Company’s corporate fixed maturity investments is an investment in the preferred equity of an insurance holding company with a fair value of $15.7 million at December 31, 2014. The Company measures the fair value of this investment using a DCF model and seeks to incorporate all relevant information reasonably available. The Company considers the contractual agreement which stipulates the methodology for calculating a dividend rate to be paid upon liquidation, conversion or redemption. At December 31, 2014, the dividend rate was 6.5%. In addition, the Company has estimated a liquidity discount of 1.0%, a risk-free rate of 0.5% and a credit spread of 0.8%. To ensure the estimate for fair value determined using the DCF model is reasonable, the Company reviews private market comparables of similar investments, if available, and in particular, credit ratings of other private market comparables for similar investments to determine the appropriateness of its estimate of fair value using a DCF model. The fair value of the Company’s investment in this corporate fixed maturity investment determined by a DCF model is positively correlated to the dividend rate, and inversely correlated to the credit spread, liquidity discount and the risk-free rate.
Other investments
Private equity partnerships
Level 3 - Included in the Company’s $281.9 million of investments in private equity partnerships at December 31, 2014 are alternative asset limited partnerships (or similar corporate structures) that invest in certain private equity asset classes including U.S. and global leveraged buyouts; mezzanine investments; distressed securities; real estate; and oil, gas and power. The fair value of private equity partnership investments is based on current estimated net asset values established in accordance with the governing documents of such investments and is obtained from the investment manager or general partner of the respective entity. The type of underlying investments held by the investee which form the basis of the net asset valuation include assets such as private business ventures, for which the Company does not have access to financial information. As a result, the Company is unable to corroborate the fair value measurement of the underlying investments of the private equity partnership and therefore requires significant management judgment to determine the fair value of the private equity partnership. In circumstances where there is a reporting lag between the current period end reporting date and the reporting date of the latest fund valuation, the Company estimates the fair value of these funds by starting with the prior quarter-end fund valuations, adjusting these valuations for actual capital calls, redemptions or distributions, as well as the impact of changes in foreign currency exchange rates, and then estimating the return for the current period. In circumstances in which the Company estimates the return for the current period, all relevant information reasonably available to the Company is utilized. This principally includes preliminary estimates reported to the Company by its fund managers, obtaining the valuation of underlying portfolio investments where such underlying investments are publicly traded and therefore have a readily observable price, using information that is available to the Company with respect to the underlying investments, reviewing various indices for similar investments or asset classes, as well as estimating returns based on the results of similar types of investments for which the Company has obtained reported results, or other valuation methods, where possible. The range of such current estimated periodic returns for the three months ended December 31, 2014 was negative 42.1% to positive 17.0% with a weighted average of positive 0.1%. The fair value of the Company’s investment in private equity partnerships is positively correlated to the estimated periodic rate of return. The Company also considers factors such as recent financial information, the value of capital transactions with the partnership and management’s judgment regarding whether any adjustments should be made to the net asset value. For each respective private equity partnership, the Company obtains and reviews the valuation methodology used by the investment manager or general partner and the latest audited annual financial statements to attempt to ensure that the investment partnership is following fair value principles consistent with GAAP in determining the net asset value of each limited partner’s interest.
Senior secured bank loan fund
Level 3 - The Company has $19.3 million invested in a closed end fund which invests primarily in loans. The Company has no right to redeem its investment in this funds. The Company’s investment in this fund is valued using the estimated monthly net asset valuation received from the investment manager. The lock up provisions in this fund result in a lack of current observable market transactions between the fund participants and the fund, and therefore, the Company considers the fair value of its investment in this fund to be determined using Level 3 inputs. The Company obtains and reviews the latest audited annual financial statements to attempt to ensure that these funds are following fair value principles consistent with GAAP in determining the net asset value. The fair value of the Company’s investment in the senior secured bank loan fund is positively correlated to the estimated monthly net asset valuations received from the investment manager.
Hedge funds
Level 3 - The Company has $2.6 million of hedge fund investments that are invested in so called “side pockets” or illiquid investments. In these instances, the Company generally does not have the right to redeem its interest, and as such, the Company classifies this portion of its investment as Level 3. The fair value of these illiquid investments is determined by adjusting the previous periods’ reported net asset value (generally one month in arrears) for an estimated periodic rate of return obtained from the respective investment manager.
For each respective hedge fund investment, the Company obtains and reviews the valuation methodology used by the investment manager and the latest audited annual financial statements to attempt to ensure that the hedge fund investment is following fair value principles consistent with GAAP in determining the net asset value.
Other assets and liabilities
Assumed and ceded (re)insurance contracts
Level 3 - The Company has a $8.7 million liability related to assumed and ceded (re)insurance contracts accounted for at fair value, with the fair value obtained through the use of an internal valuation model.  The inputs to the internal valuation model are principally based on proprietary data as observable market inputs are generally not available.  The most significant unobservable inputs include the assumed and ceded expected net cash flows related to the contracts, including the expected premium, acquisition expenses and losses; and the relevant discount rate used to present value the net cash flows.  The contract period is considered an observable input as it is defined in the contract. Generally, an increase in the net expected cash flows and expected term of the contract and a decrease in the discount rate, would result in an increase in the expected profit and ultimate fair value of the Company's assumed and ceded (re)insurance contracts.
Weather Contract
Level 3 - The Company has a $0.2 million liability related to a weather contract entered into with an insurance company, with the fair value determined through the use of an internal valuation model. Inputs to the internal valuation model are based on proprietary data as observable market inputs are not available.  The most significant unobservable input is the potential payment that would become due to a counterparty following the occurrence of a triggering event as reported by an external agency.  Generally, an increase (decrease) in the potential payment would result in an increase (decrease) to the fair value of the Company’s weather contract liability.
Below is a reconciliation of the beginning and ending balances, for the periods shown, of assets and liabilities measured at fair value on a recurring basis using Level 3 inputs. Interest and dividend income are included in net investment income and are excluded from the reconciliation.
		Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
		Fixed maturity			Other			Other assets  and (liabilities)			Total
		investments			investments
		trading
	Balance - January 1, 2013	$	27,792		$	381,067		$	21,513		$	430,372
	Total unrealized gains (losses)
	Included in net investment income	2,288			80,113			(1,331		)	81,070
	Included in other loss	—			—			(625		)	(625		)
	Total realized (losses) gains
	Included in net investment income	—			(4,114		)	—			(4,114		)
	Included in other loss	—			—			(2,083		)	(2,083		)
	Total foreign exchange losses	—			1,352			—			1,352
	Purchases	—			48,287			(1,722		)	46,565
	Settlements	(2,500		)	(95,144		)	—			(97,644		)
	Reclassified from other assets to other investments	—			18,242			(18,242		)	—
	Net transfers out of Level 3	—			(85,555		)	—			(85,555		)
	Balance - December 31, 2013	$	27,580		$	344,248		$	(2,490	)	$	369,338
	Change in unrealized gains for the period included in earnings for assets held at the end of the period included in net investment income	$	2,288		$	78,903		$	(1,331	)	$	79,860
		Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
		Fixed maturity			Other			Other assets			Total
		investments trading			investments			and
								(liabilities)
	Balance - January 1, 2014	$	27,580		$	344,248		$	(2,490	)	$	369,338
	Total unrealized gains (losses)
	Included in net investment income	12,724			1,045			1,455			15,224
	Total realized losses
	Included in other loss	—			—			1,262			1,262
	Total foreign exchange gains	—			(3,279		)	(21		)	(3,300		)
	Purchases	—			43,130			(9,140		)	33,990
	Settlements	—			(81,326		)	—			(81,326		)
	Net transfers out of Level 3	(24,644		)	—			—			(24,644		)
	Balance - December 31, 2014	$	15,660		$	303,818		$	(8,934	)	$	310,544
	Change in unrealized gains for the period included in earnings for assets held at the end of the period included in net investment income	$	(66	)	$	1,045		$	1,455		$	2,434
Financial Instruments Disclosed, But Not Carried, at Fair Value
The Company uses various financial instruments in the normal course of its business. The Company’s insurance contracts are excluded from the fair value of financial instruments accounting guidance, unless the Company elects the fair value option, and therefore, are not included in the amounts discussed herein. The carrying values of cash, accrued interest, receivables for investments sold, certain other assets, payables for investments purchased, certain other liabilities, and other financial instruments not included herein approximated their fair values.
Senior Notes
In March 2010, RenRe North America Holdings Inc. (“RRNAH”) issued $250.0 million of 5.75% Senior Notes due March 15, 2020, with interest on the notes payable on March 15 and September 15 of each year. At December 31, 2014, the fair value of the 5.75% Senior Notes was $279.0 million (2013 - $273.9 million).
The fair value of RRNAH’s 5.75% Senior Notes is determined using indicative market pricing obtained from third-party service providers, which the Company considers Level 2 in the fair value hierarchy. There have been no changes during the period in the Company’s valuation technique used to determine the fair value of the Senior Notes.
The Fair Value Option for Financial Assets and Financial Liabilities
The Company has elected to account for certain financial assets and financial liabilities at fair value using the guidance under FASB ASC Topic Financial Instruments as the Company believes it represents the most meaningful measurement basis for these assets and liabilities. Below is a summary of the balances the Company has elected to account for at fair value:
		2014			2013
	Other investments	$	504,147		$	573,264
	Other assets (liabilities)	$	(8,744	)	$	—
Included in net investment income for the year ended December 31, 2014 was net unrealized losses of $1.4 million related to the changes in fair value of other investments (2013 – gains of $75.8 million, 2012 – gains of $38.2 million). Net unrealized losses related to the changes in the fair value of other assets and liabilities recorded in other loss was $Nil for the year ended December 31, 2014 (2013 – $Nil, 2012 – $3.2 million).
Measuring the Fair Value of Other Investments Using Net Asset Valuations
The table below shows the Company’s portfolio of other investments measured using net asset valuations:
	At December 31, 2014	Fair Value			Unfunded			Redemption Frequency		Redemption	Redemption
					Commitments					Notice Period (Minimum Days)	Notice Period (Maximum Days)
	Private equity partnerships	$	281,932		$	77,712		See below		See below	See below
	Senior secured bank loan fund	19,316			6,301			See below		See below	See below
	Hedge funds	2,570			—			See below		See below	See below
	Total other investments measured using net asset valuations	$	303,818		$	84,013
Private equity partnerships – Included in the Company’s investments in private equity partnerships are alternative asset limited partnerships (or similar corporate structures) that invest in certain private equity asset classes including U.S. and global leveraged buyouts; mezzanine investments; distressed securities; real estate; and oil, gas and power. The fair values of the investments in this category have been estimated in respect of the net asset value of the investments, as discussed in detail above. The Company generally has no right to redeem its interest in any of these private equity partnerships in advance of dissolution of the applicable private equity partnership. Instead, the nature of these investments is that distributions are received by the Company in connection with the liquidation of the underlying assets of the respective private equity partnership. It is estimated that the majority of the underlying assets of the limited partnerships would liquidate over 7 to 10 years from inception of the respective limited partnership.
Senior secured bank loan fund – The Company has $19.3 million invested in a closed end fund which invests primarily in loans. The Company has no right to redeem its investment in this fund. The Company’s investment in this fund is valued using the estimated monthly net asset valuation received from the investment manager, as discussed in detail above. It is estimated that the majority of the underlying assets in this closed end fund would liquidate over 4 to 5 years from inception of the fund.
Hedge funds – The Company invests in hedge funds that pursue multiple strategies. The fair values of the investments in this category are estimated using the net asset value per share of the funds, as discussed in detail above. The Company’s investments in hedge funds at December 31, 2014 are $2.6 million of so called “side pocket” investments which are not redeemable at the option of the shareholder. The Company will retain its interest in the side pocket investments, referred to above, until the underlying investments attributable to such side pockets are liquidated, realized or deemed realized at the discretion of the fund manager.

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2014
Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Abstract]
Reinsurance	REINSURANCE
	The Company purchases reinsurance and other protection to manage its risk portfolio and to reduce its exposure to large losses. The Company currently has in place contracts that provide for recovery of a portion of certain claims and claim expenses, generally in excess of various retentions or on a proportional basis. In addition to loss recoveries, certain of the Company’s ceded reinsurance contracts provide for recoveries of additional premiums, for reinstatement premiums and for lost no-claims bonuses, which are incurred when losses are ceded to other reinsurance contracts. The Company remains liable to the extent that any reinsurance company fails to meet its obligations.
	The following table sets forth the effect of reinsurance and retrocessional activity on premiums written and earned and on net claims and claim expenses incurred:
		Year ended December 31,	2014			2013			2012
		Premiums written
		Direct	$	76,511		$	54,334		$	36,367
		Assumed	1,474,061			1,551,078			1,515,224
		Ceded	(482,336		)	(401,465		)	(448,934		)
		Net premiums written	$	1,068,236		$	1,203,947		$	1,102,657
		Premiums earned
		Direct	$	66,027		$	44,530		$	34,028
		Assumed	1,450,047			1,482,511			1,465,701
		Ceded	(453,658		)	(412,415		)	(430,374		)
		Net premiums earned	$	1,062,416		$	1,114,626		$	1,069,355
		Claims and claim expenses
		Gross claims and claim expenses incurred	$	228,581		$	185,139		$	403,491
		Claims and claim expenses recovered	(30,634		)	(13,852		)	(78,280		)
		Net claims and claim expenses incurred	$	197,947		$	171,287		$	325,211
	The reinsurers with the three largest balances accounted for 35.4%, 14.9% and 7.0%, respectively, of the Company’s reinsurance recoverable balance at December 31, 2014 (2013 - 28.2%, 19.9% and 11.0%, respectively). The valuation allowance recorded against reinsurance recoverable was $1.0 million at December 31, 2014 (2013 - $1.7 million). The three largest company-specific components of the valuation allowance represented 17.9%, 4.0% and 2.9%, respectively, of the Company’s total valuation allowance at December 31, 2014 (2013 - 14.2%, 12.5% and 3.1%, respectively).

Reserve_for_Claims_and_Claim_E

Reserve for Claims and Claim Expenses	12 Months Ended
	Dec. 31, 2014
Insurance Loss Reserves [Abstract]
Reserve for Claims and Claim Expenses	RESERVE FOR CLAIMS AND CLAIM EXPENSES
	The Company uses statistical and actuarial methods to estimate ultimate expected claims and claim expenses. The period of time from the reporting of a claim to the Company and the settlement of the Company’s liability may be many years. During this period, additional facts and trends will be revealed. As these factors become apparent, case reserves will be adjusted, sometimes requiring an increase or decrease in the overall reserve for claims and claim expenses of the Company, and at other times requiring a reallocation of incurred but not reported (“IBNR”) reserves to specific case reserves or additional case reserves. These estimates are reviewed regularly, and such adjustments, if any, are reflected in the results of operations in the period in which they become known and are accounted for as changes in estimates. Adjustments to the Company’s reserve for claims and claim expenses can impact current year net income (loss) by decreasing net income or increasing net loss if the estimates of prior years claims and claim expense reserves prove to be insufficient or by increasing net income or decreasing net loss if the estimates of prior years claims and claim expense reserves prove to be overstated.
	The Company’s estimates of claims and claim expenses are also based in part upon the estimation of claims resulting from natural and man-made disasters such as hurricanes, earthquakes, tsunamis, tornadoes, floods, winter storms, terrorist attacks and other catastrophic events. Estimation by the Company of claims resulting from catastrophic events is inherently difficult because of the potential severity of property catastrophe claims. Additionally, the Company has recently increased its specialty reinsurance business but does not have the benefit of a significant amount of its own historical experience in certain of these lines of business. Therefore, the Company uses both proprietary and commercially available models, as well as historical (re)insurance industry claims experience, for purposes of evaluating future trends and providing an estimate of ultimate claims costs.
	Activity in the liability for unpaid claims and claim expenses is summarized as follows:
		Year ended December 31,	2014			2013			2012
		Net reserves as of January 1	$	1,462,705		$	1,686,865		$	1,588,325
		Net incurred related to:
		Current year	341,745			315,241			483,180
		Prior years	(143,798		)	(143,954		)	(157,969		)
		Total net incurred	197,947			171,287			325,211
		Net paid related to:
		Current year	39,830			32,212			84,056
		Prior years	275,006			363,235			142,615
		Total net paid	314,836			395,447			226,671
		Net reserves as of December 31	1,345,816			1,462,705			1,686,865
		Reinsurance recoverable as of December 31	66,694			101,025			192,512
		Gross reserves as of December 31	$	1,412,510		$	1,563,730		$	1,879,377
	The following table details the Company’s prior year development by segment of its liability for unpaid claims and claim expenses:
		Year ended December 31,	2014			2013			2012
		Catastrophe Reinsurance	$	(65,511	)	$	(102,037	)	$	(110,568	)
		Specialty Reinsurance	(55,909		)	(34,111		)	(34,146		)
		Lloyd’s	(16,241		)	(8,256		)	(16,202		)
		Other	(6,137		)	450			2,947
		Total favorable development of prior accident years net claims and claim expenses	$	(143,798	)	$	(143,954	)	$	(157,969	)
	Catastrophe Reinsurance Segment
	The Company reviews substantially all of its catastrophe reinsurance claims and claim expense reserves quarterly. The Company’s quarterly review procedures include identifying events that have occurred up to the latest balance sheet date, determining the Company’s best estimate of the ultimate expected cost to settle all claims and administrative costs associated with those new events which have arisen during the reporting period, reviewing the ultimate expected cost to settle claims and administrative costs associated with those events which occurred during previous periods, and considering new estimation techniques, such as additional actuarial methods or other statistical techniques, that can assist the Company in developing its best estimate. This process is judgmental in that it involves reviewing changes in paid and reported claims each period and adjusting the Company’s estimates of the ultimate expected claims for each event where there are developments that are different from the Company’s previous expectations. If the Company determines that adjustments to an earlier estimate are appropriate, such adjustments are recorded in the period in which they are identified. The level of the Company’s claims associated with certain catastrophes can be very large. For example, within the Company’s Catastrophe Reinsurance segment, initial estimated ultimate claims associated with the 2005 Hurricanes, Katrina, Rita and Wilma, were over $1.3 billion, the 2008 Hurricanes (Gustav and Ike), were over $530 million and the large losses of 2011 (including the 2011 New Zealand Earthquake, the Tohoku Earthquake, the large U.S. tornadoes, flooding in Australia, certain aggregate losses, Hurricane Irene and the Thailand Floods) were over $1.1 billion. As a result, small percentage changes in the estimated ultimate claims of large catastrophic events can significantly impact the Company’s reserves for claims and claim expenses in subsequent periods.
	Specialty Reinsurance Segment
	When initially developing reserving techniques for the Company’s specialty reinsurance coverages, the Company considered estimating reserves utilizing several actuarial techniques such as paid and reported claims development methods. The Company elected to use the Bornhuetter-Ferguson actuarial method because this method is appropriate for lines of business, such as its specialty reinsurance business, where there is a lack of historical claims experience. This method allows for greater weight to be applied to expected results in periods where little or no actual experience is available, and, hence, is less susceptible to the potential pitfall of being excessively impacted by one particular year or quarter of actual paid and/or reported claims data. This method uses initial expected claims ratio expectations to the extent that claims are not paid or reported, and it assumes that past experience is not fully representative of the future. As the Company’s reserves for claims and claim expenses age, and actual claims experience becomes available, this method places less weight on expected experience and places more weight on actual experience. This experience, which represents the difference between expected reported claims and actual reported claims is reflected in the respective reporting period as a change in estimate. The Company reevaluates its actuarial reserving techniques on a periodic basis.
	The Company reviews substantially all of its specialty reinsurance claims and claim expense reserves quarterly. Typically, the quarterly review procedures include reviewing paid and reported claims in the most recent reporting period, reviewing the development of paid and reported claims from prior periods, and reviewing the Company’s overall experience by underwriting year and in the aggregate. The Company monitors its expected ultimate claims and claim expense ratios and expected claims reporting assumptions on a quarterly basis and compares them to its actual experience. These actuarial assumptions are generally reviewed annually, based on input from the Company’s actuaries, underwriters, claims personnel and finance professionals, although adjustments may be made more frequently if needed. Assumption changes are made to adjust for changes in the pricing and terms of coverage the Company provides, changes in industry results for similar business, as well as its actual experience, to the extent the Company has enough data to rely on its own experience. If the Company determines that adjustments to an earlier estimate are appropriate, such adjustments are recorded in the period in which they are identified.
	Lloyd’s Segment
	The Company uses the Bornhuetter-Ferguson actuarial method to estimate claims and claim expenses within its Lloyd’s segment for its property and casualty (re)insurance contracts and quota share reinsurance business. The comments discussed above relating to the Company’s reserving techniques and processes for the Company’s Specialty Reinsurance segment also apply to the Company’s Lloyd’s segment. In addition, certain of the Company’s coverages may be impacted by natural and man-made catastrophes. The Company estimates claim reserves for these claims after the event giving rise to these claims occurs, following a process that is similar to the Company’s Catastrophe Reinsurance segment discussed above.
	Other Category
	The Company uses the Bornhuetter-Ferguson actuarial method to estimate claims and claim expenses within its Other category for its property and casualty insurance contracts and quota share reinsurance business. The comments discussed above relating to the Company’s reserving techniques and processes for its Specialty Reinsurance and Lloyd’s segments also apply to the Company’s Other category. In addition, certain of the Company’s coverages may be impacted by natural and man-made catastrophes. The Company estimates claim reserves for these claims after the event giving rise to these claims occurs, following a process that is similar to the Company’s Catastrophe Reinsurance segment discussed above.
	Development of Liability for Unpaid Claims and Claim Expenses
	The following table details the development of the Company’s liability for unpaid claims and claim expenses for each of its Catastrophe Reinsurance, Specialty Reinsurance and Lloyd’s segments and Other category, for the year ended December 31, 2014 split between catastrophe net claims and claim expenses and attritional net claims and claim expenses:
		Year ended December 31, 2014	Catastrophe Reinsurance Segment			Specialty Reinsurance Segment			Lloyd's Segment			Other			Total
		Catastrophe net claims and claim expenses
		Large catastrophe events
		Storm Sandy (2012)	$	(20,104	)	$	—		$	(4,128	)	$	—		$	(24,232	)
		April and May U.S. Tornadoes (2011)	(13,939		)	—			—			—			(13,939		)
		Thailand Floods (2011)	(9,254		)	(2,500		)	—			—			(11,754		)
		LIBOR (2011 and 2012)	—			(10,500		)	(1,250		)	—			(11,750		)
		Hurricanes Gustav and Ike (2008)	(6,647		)	—			—			—			(6,647		)
		Tohoku Earthquake and Tsunami (2011)	(3,489		)	(1,642		)	—			—			(5,131		)
		Hurricane Irene (2011)	(4,506		)	—			—			—			(4,506		)
		Windstorm Kyrill (2007)	(3,615		)	—			—			—			(3,615		)
		Subprime (2007)	—			5,049			—			—			5,049
		New Zealand Earthquake (2010)	24,692			—			—			—			24,692
		Other	(10,644		)	(1,826		)	(1,234		)	—			(13,704		)
		Total large catastrophe events	(47,506		)	(11,419		)	(6,612		)	—			(65,537		)
		Small catastrophe events
		European Floods (2013)	(7,552		)	—			—			—			(7,552		)
		U.S. PCS 24 Wind and Thunderstorm (2013)	(6,712		)	—			—			—			(6,712		)
		U.S. PCS 70 and 73 Wind and Thunderstorm (2012)	13,362			—			—			—			13,362
		Other	(17,103		)	—			(2,687		)	(6,137		)	(25,927		)
		Total small catastrophe events	(18,005		)	—			(2,687		)	(6,137		)	(26,829		)
		Total catastrophe net claims and claim expenses	$	(65,511	)	$	(11,419	)	$	(9,299	)	$	(6,137	)	$	(92,366	)
		Attritional net claims and claim expenses
		Bornhuetter-Ferguson actuarial method - actual reported claims less than expected claims	$	—		$	(44,490	)	$	(6,942	)	$	—		$	(51,432	)
		Total attritional net claims and claim expenses	$	—		$	(44,490	)	$	(6,942	)	$	—		$	(51,432	)
		Total favorable development of prior accident years net claims and claim expenses	$	(65,511	)	$	(55,909	)	$	(16,241	)	$	(6,137	)	$	(143,798	)
	Catastrophe Reinsurance Segment
	The favorable development of prior accident years net claims and claim expenses within the Company’s Catastrophe Reinsurance segment in 2014 of $65.5 million was comprised of $47.5 million and $18.0 million related to large and small catastrophe events, respectively. Included in the favorable development of prior accident years net claims and claim expenses related to large catastrophe events was $20.1 million, $13.9 million, $9.3 million and $6.6 million related to Storm Sandy, the 2011 April and May U.S. Tornadoes, the 2011 Thailand Floods and the 2008 Hurricanes (Gustav and Ike), partially offset by adverse development of $24.7 million related to the 2010 New Zealand Earthquake, each principally the result of changes in estimated ultimate losses for each respective event. Included in the favorable development of prior accident years net claims and claim expenses related to small catastrophe events was $7.6 million and $6.7 million related to the 2013 European Floods and a 2013 U.S. wind and thunderstorm event, partially offset by adverse development of $13.4 million related certain 2012 U.S. wind and thunderstorm events, each principally the result of changes in estimated ultimate losses for each respective event.
	Specialty Reinsurance Segment
The favorable development of prior accident years net claims and claim expenses within the Company’s Specialty Reinsurance segment in 2014 of $55.9 million was comprised of $11.4 million and $44.5 million related to large catastrophe events and attritional net claims and claim expenses, respectively. Included in the favorable development of prior accident years net claims and claim expenses related to large catastrophe events was a $10.5 million reduction in estimated ultimate losses with respect to potential exposure to LIBOR related claims from prior accident years, partially offset by adverse development of $5.0 million from subprime related events from 2007 driven by reported claims from a number of cedants. Favorable development of prior accident years net claims and claim expenses of $44.5 million related to attritional net claims and claim expenses was driven by the application of the Company's formulaic actuarial reserving methodology. There were no actuarial reserving assumption changes during 2014.
Lloyd’s Segment
The favorable development of prior accident years net claims and claim expenses within the Company’s Lloyd’s segment of $16.2 million was comprised of $6.6 million, $2.7 million and $6.9 million related to large catastrophe events, small catastrophe events and attritional net claims and claim expenses, respectively. Included in the favorable development of prior accident years net claims and claim expenses is a $4.1 million reduction in the estimated ultimate loss related to Storm Sandy included in large catastrophe events, with the $6.9 million favorable development of prior accident years net claims and claim expenses related to attritional net claims and claim expenses principally due to reported claims activity coming in lower than expected on prior accident years events. There were no actuarial reserving assumption changes during 2014.
Other Category
The favorable development on prior accident years of $6.1 million for 2014 within the Company’s Other category was principally the result of a reduction in the estimated ultimate losses on a proportional property contract.
The following table details the development of the Company’s liability for unpaid claims and claim expenses for each of its Catastrophe Reinsurance, Specialty Reinsurance and Lloyd’s segments and Other category, for the year ended December 31, 2013 split between catastrophe net claims and claim expenses and attritional net claims and claim expenses:
	Year ended December 31, 2013	Catastrophe Reinsurance Segment			Specialty Reinsurance Segment			Lloyd's Segment			Other			Total
	Catastrophe net claims and claim expenses
	Large catastrophe events
	Storm Sandy (2012)	$	(44,460	)	$	—		$	(3,825	)	$	—		$	(48,285	)
	Tohoku Earthquake and Tsunami (2011)	(18,033		)	(1,000		)	—			—			(19,033		)
	Hurricanes Gustav and Ike (2008)	(16,261		)	—			—			(404		)	(16,665		)
	New Zealand Earthquake (2011)	(10,944		)	—			—			—			(10,944		)
	Windstorm Kyrill (2007)	(8,244		)	—			—			—			(8,244		)
	Hurricane Isaac (2012)	2,610			—			—			—			2,610
	New Zealand Earthquake (2010)	11,040			300			—			—			11,340
	Other	(776		)	(1,763		)	(1,442		)	(1,325		)	(5,306		)
	Total large catastrophe events	(85,068		)	(2,463		)	(5,267		)	(1,729		)	(94,527		)
	Small catastrophe events
	U.S. PCS 83 Wind and Thunderstorm (2012)	(3,500		)	—			—			—			(3,500		)
	U.S. PCS 76 Wind and Thunderstorm (2012)	(300		)	—			—			—			(300		)
	U.S. PCS 70 Wind and Thunderstorm (2012)	8,225			—			—			—			8,225
	Other	(21,394		)	—			—			—			(21,394		)
	Total small catastrophe events	(16,969		)	—			—			—			(16,969		)
	Total catastrophe net claims and claim expenses	$	(102,037	)	$	(2,463	)	$	(5,267	)	$	(1,729	)	$	(111,496	)
	Attritional net claims and claim expenses
	Bornhuetter-Ferguson actuarial method - actual reported claims less than expected claims	$	—		$	(21,216	)	$	(3,263	)	$	2,179		$	(22,300	)
	Actuarial assumption changes	—			(10,432		)	274			—			(10,158		)
	Total attritional net claims and claim expenses	$	—		$	(31,648	)	$	(2,989	)	$	2,179		$	(32,458	)
	Total favorable development of prior accident years net claims and claim expenses	$	(102,037	)	$	(34,111	)	$	(8,256	)	$	450		$	(143,954	)
Catastrophe Reinsurance Segment
The favorable development of prior accident years net claims and claim expenses within the Company’s Catastrophe Reinsurance segment in 2013 of $102.0 million was primarily due to $44.5 million, $18.0 million, $16.3 million and $10.9 million of favorable development related to reductions in the expected ultimate net loss for Storm Sandy, the Tohoku Earthquake, the 2008 Hurricanes (Gustav and Ike) and the 2011 New Zealand Earthquake, respectively, as reported claims came in better than expected, and $34.2 million of net favorable development related to a number of other catastrophes principally the result of reported claims coming in less than expected, resulting in decreases to the ultimate claims for these events through the application of the Company’s formulaic actuarial reserving methodology. Partially offsetting the reductions noted above was adverse development on the 2010 New Zealand Earthquake, U.S. PSC 70 and Hurricane Isaac of $11.0 million, $8.2 million and $2.6 million, respectively, associated with an increase in reported gross ultimate losses.
Specialty Reinsurance Segment
The favorable development of prior accident years net claims and claim expenses within the Company’s Specialty Reinsurance segment in 2013 of $34.1 million was primarily driven by $10.4 million associated with actuarial assumption changes, principally in the Company’s casualty clash and casualty risk lines of business, and primarily as a result of revised claim development factors based on actual loss experience, and $23.7 million due to reported claims coming in lower than expected on prior accident years events, as a result of the application of the Company’s formulaic actuarial reserving methodology.
Lloyd’s Segment
The favorable development of prior accident years net claims and claim expenses within the Company’s Lloyd’s segment of $8.3 million during 2013 was principally driven by a $5.3 million decrease in the estimated ultimate net claims and claim expenses related to large catastrophes, including $3.8 million related to Storm Sandy, and $3.3 million related to reported claims coming in lower than expected on prior accident years events as a result of the application of the Company’s formulaic actuarial reserving methodology and partially offset by adverse development of $0.3 million related to assumption changes.
Other Category
The net adverse development on prior accident years of $0.5 million for 2013 within the Company’s Other category was principally the result of $2.2 million related to the application of the Company’s formulaic actuarial reserving methodology with the increases being due to actual paid and reported claim activity coming in higher than what was originally anticipated when setting the initial reserves; partially offset by favorable development of $1.7 million related to large catastrophe events.
The following table details the development of the Company’s liability for unpaid claims and claim expenses for each of its Catastrophe Reinsurance, Specialty Reinsurance and Lloyd’s segments and Other category, for the year ended December 31, 2012 split between catastrophe net claims and claim expenses and attritional net claims and claim expenses:
	Year ended December 31, 2012	Catastrophe Reinsurance Segment			Specialty Reinsurance Segment			Lloyd’s Segment			Other			Total
	Catastrophe net claims and claim expenses
	Large catastrophe events
	Chile Earthquake (2010)	$	(24,575	)	$	—		$	—		$	—		$	(24,575	)
	Hurricanes Gustav and Ike (2008)	(17,541		)	—			—			(2,926		)	(20,467		)
	U.K. Floods (2007)	(17,271		)	—			—			—			(17,271		)
	Hurricanes Katrina, Rita and Wilma (2005)	(6,420		)	(3,000		)	—			1,690			(7,730		)
	Hurricane Irene (2011)	(4,630		)	—			(2,500		)	—			(7,130		)
	Thailand Floods (2011)	(3,933		)	—			(5,500		)	—			(9,433		)
	Tohoku Earthquake and Tsunami (2011)	(3,896		)	—			—			—			(3,896		)
	Windstorm Kyrill (2007)	(3,417		)	—			—			—			(3,417		)
	New Zealand Earthquake (2010)	3,570			—			—			—			3,570
	New Zealand Earthquake (2011)	17,912			—			—			—			17,912
	Other	(2,542		)	—			(1,476		)	65			(3,953		)
	Total large catastrophe events	(62,743		)	(3,000		)	(9,476		)	(1,171		)	(76,390		)
	Small catastrophe events
	Danish Floods (2011)	(5,000		)	—			—			—			(5,000		)
	U.S. PCS 63 Winter Storm (2011)	(5,000		)	—			—			—			(5,000		)
	U.S. PCS 42 Winter Storm (2011)	(2,560		)	—			—			—			(2,560		)
	U.S. PCS 53 Winter Storm (2011)	(2,558		)	—			—			—			(2,558		)
	Other	(32,707		)	—			—			—			(32,707		)
	Total small catastrophe events	(47,825		)	—			—			—			(47,825		)
	Total catastrophe net claims and claim expenses	$	(110,568	)	$	(3,000	)	$	(9,476	)	$	(1,171	)	$	(124,215	)
	Attritional net claims and claim expenses
	Bornhuetter-Ferguson actuarial method - actual reported claims less than expected claims	$	—		$	(16,747	)	$	(8,011	)	$	4,118		$	(20,640	)
	Actuarial assumption changes	—			(14,399		)	1,285			—			(13,114		)
	Total attritional net claims and claim expenses	$	—		$	(31,146	)	$	(6,726	)	$	4,118		$	(33,754	)
	Total favorable development of prior accident years net claims and claim expenses	$	(110,568	)	$	(34,146	)	$	(16,202	)	$	2,947		$	(157,969	)
Catastrophe Reinsurance Segment
The favorable development of prior accident years net claims and claim expenses within the Company’s Catastrophe Reinsurance segment in 2012 of $110.6 million was primarily due to net reductions of $84.2 million arising from the estimated ultimate claims of large catastrophe events, including the 2010 Chilean Earthquake, the 2008 Hurricanes (Gustav and Ike), the 2007 U.K. Flooding, the 2005 Hurricanes, Hurricane Irene of 2011, the 2011 Thailand Floods and the Tohoku Earthquake, as reported claims came in better than expected. The remainder of the favorable development of prior accident years net claims and claim expenses of $47.8 million was due to a reduction in ultimate claims on a number of relatively small catastrophes, all principally the result of reported claims coming in less than expected, principally resulting in formulaic decreases to the ultimate claims for these events. Partially offsetting the reductions noted above was a $17.9 million and $3.6 million increase in net claims and claim expenses from the 2011 and 2010 New Zealand Earthquake, respectively, primarily as a result of increased cedant gross ultimate loss estimates.
Specialty Reinsurance Segment
The favorable development of prior accident years net claims and claim expenses within the Company’s Specialty Reinsurance segment in 2012 of $34.1 million includes $14.4 million associated with actuarial assumption changes, principally in the Company’s casualty and medical malpractice lines of business, and primarily as a result of revised initial expected claims ratios and claim development factors due to actual experience coming in better than expected, and $16.7 million due to reported claims coming in lower than expected on prior accident years events, as a result of the application of the Company’s formulaic actuarial reserving methodology, and $3.0 million related to reductions in the estimated ultimate losses from the 2005 Hurricanes.
Lloyd’s Segment
The favorable development of prior accident years net claims and claim expenses within the Company’s Lloyd’s segment of $16.2 million during 2012 was principally due to favorable development of $8.0 million due to reported claims coming in lower than expected on a number of prior accident years events, as a result of the application of the Company’s formulaic actuarial reserving methodology, $5.5 million related to the 2011 Thailand Floods, $2.5 million related to Hurricane Irene, and $1.5 million due to lower than expected reported claims for catastrophe losses within the Lloyd’s segment’s property catastrophe reinsurance book of business, partially offset by $1.3 million of adverse development related to actuarial assumption changes.
Other Category
The net adverse development on prior accident years of $2.9 million for 2012 within the Company’s Other category was principally the result of a loss portfolio transfer entered into by the Company on October 1, 2012, in respect of its contractor’s liability book of business within RenaissanceRe Specialty Risks, whereby the Company paid consideration of $36.5 million to transfer net liabilities of $29.1 million, resulting in a loss of $7.4 million which is recorded above as prior accident years attritional net claims and claims expenses in the Company’s Other category, partially offset by reductions in reported losses on certain attritional loss contracts and favorable development related to catastrophe events, primarily the 2008 Hurricanes (Gustav and Ike).
Assumed Reinsurance Contracts Classified As Deposit Contracts
Net claims and claim expenses incurred were reduced by $0.3 million during 2014 (2013 – $0.4 million, 2012 – $0.1 million) related to income earned on assumed reinsurance contracts that were classified as deposit contracts with underwriting risk only.  Other loss was decreased by $0.1 million during 2014 (2013 – other loss decreased by $0.1 million, 2012 – other loss decreased by $7.5 million) related to premiums and losses incurred on assumed reinsurance contracts that were classified as deposit contracts with timing risk only.  Aggregate deposit liabilities of $39.0 million are included in reinsurance balances payable at December 31, 2014 (2013 – $39.7 million) and aggregate deposit assets of $Nil are included in other assets at December 31, 2014 (2013 – $Nil) associated with these contracts.

Debt_and_Credit_Facilities

Debt and Credit Facilities	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt and Credit Facilities	DEBT AND CREDIT FACILITIES
	5.75% Senior Notes
	On March 17, 2010, RRNAH issued $250.0 million of its 5.75% Senior Notes due March 15, 2020, with interest on the notes payable on March 15 and September 15 of each year. The notes, which are senior obligations, are guaranteed by RenaissanceRe and can be redeemed by RRNAH prior to maturity, subject to the payment of a “make-whole” premium. The notes were issued pursuant to an Indenture, dated as of March 17, 2010, by and among RenaissanceRe, RRNAH, and Deutsche Bank Trust Company Americas, as trustee (the “Trustee”), as supplemented by the First Supplemental Indenture, dated as of March 17, 2010. The notes, which are senior obligations, contain various covenants, including limitations on mergers and consolidations, restrictions as to the disposition of the stock of designated subsidiaries and limitations on liens of the stock of designated subsidiaries.
	5.875% Senior Notes
	In January 2003, RenaissanceRe issued $100.0 million, which represented the carrying amount on the Company’s consolidated balance sheet, of 5.875% Senior Notes due February 15, 2013, with interest on the notes payable on February 15 and August 15 of each year. RenaissanceRe repaid the full $100.0 million of its outstanding 5.875% Senior Notes upon their scheduled maturity of February 15, 2013 using available cash and investments.
	RenaissanceRe Revolving Credit Facility
	RenaissanceRe is a party to a credit agreement, dated as of May 17, 2012 (the “Credit Agreement”), with various banks and financial institutions parties thereto (collectively, the “Lenders”), Wells Fargo Bank, National Association (“Wells Fargo”), as fronting bank, letter of credit administrator and administrative agent (the “Administrative Agent”) for the Lenders, and certain other agents. The Credit Agreement previously provided for commitments from the Lenders in an aggregate amount of $150.0 million, including the issuance of letters of credit for the respective accounts of RenaissanceRe and certain of RenaissanceRe’s subsidiaries. Effective as of May 23, 2013, RenaissanceRe entered into a First Amendment and Joinder to Credit Agreement (the “Amendment”) with the Administrative Agent and the Lenders. Among other items, the Amendment (i) increased the aggregate commitment of the Lenders to $250.0 million, (ii) added an additional bank as a Lender, and (iii) eliminated the commitment of the Lenders to issue letters of credit. After giving effect to the Amendment, RenaissanceRe has the right, subject to certain conditions, to increase the size of the facility up to $350.0 million.
	Amounts borrowed under the Credit Agreement bear interest at a rate selected by RenaissanceRe equal to the Base Rate or LIBOR (each as defined in the Credit Agreement) plus a margin, all as more fully set forth in the Credit Agreement. At December 31, 2014, the Company has not borrowed any amounts under the Credit Agreement.
	The Credit Agreement contains representations, warranties and covenants customary for bank loan facilities of this type. In addition to customary covenants which limit RenaissanceRe and its subsidiaries’ ability to merge, consolidate, enter into negative pledge agreements, sell a substantial amount of assets, incur liens and declare or pay dividends under certain circumstances, the Credit Agreement also contains certain financial covenants. These financial covenants generally provide that consolidated debt to capital shall not exceed the ratio of 0.35:1 and that for the year ending December 31, 2014, the consolidated net worth of RenaissanceRe and Renaissance Reinsurance shall equal or exceed approximately $2.3 billion and $1.1 billion, respectively (the “Net Worth Requirements”). The Net Worth Requirements are recalculated effective as of the end of each fiscal year, all as more fully set forth in the Credit Agreement.
	In the event of the occurrence and continuation of certain events of default, the Administrative Agent shall, at the request of the Required Lenders (as defined in the Credit Agreement), or may, with the consent of the Required Lenders, among other things, take any or all of the following actions: terminate the Lenders’ obligations to make loans and accelerate the outstanding obligations of RenaissanceRe under the Credit Agreement.
	The commitments under the Credit Agreement expire on May 17, 2015. Our ability to renew the Credit Agreement, and the terms of such renewal, if any, will depend upon the facts and circumstances at the time, including our financial position, operating results and credit and capital market conditions. In the event that RenaissanceRe is unable to renew the Credit Agreement at a reasonable price and otherwise on terms satisfactory to it or at all, or if RenaissanceRe decides not to renew the Credit Agreement in whole or in part, it may pursue alternative financing arrangements in order to meet its ongoing liquidity needs.
	Standby Letter of Credit Facility
	Effective as of December 23, 2014, RenaissanceRe and certain of its affiliates, Renaissance Reinsurance, RenaissanceRe Specialty Risks and DaVinci (such affiliates, collectively, the “Applicants”), entered into a Standby Letter of Credit Agreement (the “Standby Letter of Credit Agreement”) with Wells Fargo. The Standby Letter of Credit Agreement provides for a secured, uncommitted facility under which letters of credit may be issued from time to time for the respective accounts of the Applicants. RenaissanceRe has unconditionally guaranteed the payment obligations of Renaissance Reinsurance and Renaissance Specialty Risks under the Standby Letter of Credit Agreement and all other related credit documents.
	The Standby Letter of Credit Agreement replaced the Fourth Amended and Restated Reimbursement Agreement, dated as of May 17, 2012 (the “Terminated Facility”), which was terminated concurrently with the effectiveness of the Standby Letter of Credit Agreement. As of the effective date of the Standby Letter of Credit Agreement, all letters of credit that had been issued under the Terminated Facility and remained outstanding as of such date were transferred to, and became governed by the terms and conditions of, the Standby Letter of Credit Agreement.
	In the Standby Letter of Credit Agreement, each of RenaissanceRe and the Applicants makes, as to itself, certain representations and warranties and severally agrees to comply with certain covenants, in each case, that are customary for facilities of this type. Under the Standby Letter of Credit Agreement, each Applicant is severally required to pledge to Wells Fargo eligible collateral having a value, as determined as therein provided, that equals or exceeds at all times the aggregate stated amount of the outstanding letters of credit issued for its account plus all such Applicant’s payment and reimbursement obligations in respect of such letters of credit and under the Standby Letter of Credit Agreement. In the case of an event of default under the Standby Letter of Credit Agreement, Wells Fargo may exercise certain remedies, including conversion of collateral of a defaulting Applicant into cash.
	At December 31, 2014, the Applicants had $83.6 million of letters of credit with effective dates on or before December 31, 2014 outstanding under the Standby Letters of Credit Agreement.
	Bilateral Letter of Credit Facility (“Bilateral Facility”)
	Effective October 1, 2013, each of ROE and RenaissanceRe Specialty U.S. became parties to the existing Bilateral Facility provided pursuant to the facility letter, dated September 17, 2010 and amended July 14, 2011 (as so amended, the “Facility Letter”), among Citibank Europe plc (“CEP”) and the then existing participants: Renaissance Reinsurance, DaVinci and RenaissanceRe Specialty Risks (collectively, with ROE and RenaissanceRe Specialty U.S., the “Bilateral Facility Participants”).
	The Bilateral Facility provides a commitment from CEP to issue letters of credit for the account of one or more of the Bilateral Facility Participants (inclusive of ROE and RenaissanceRe Specialty U.S.) and their respective subsidiaries in multiple currencies and in an aggregate amount of up to $300.0 million, subject to a sublimit of $50.0 million for letters of credit issued for the account of RenaissanceRe Specialty U.S. The Bilateral Facility was to expire on December 31, 2014; however effective December 23, 2014, the Bilateral Facility was extended to December 31, 2015. The Bilateral Facility is evidenced by the Facility Letter and five separate master agreements between CEP and each of the Bilateral Facility Participants, as well as certain ancillary agreements. At December 31, 2014, $123.2 million was outstanding and $176.8 million remained unused and available to the Bilateral Facility Participants under the Bilateral Facility.
	Under the Bilateral Facility, each of the Bilateral Facility Participants is severally obligated to pledge to CEP at all times during the term of the Bilateral Facility certain securities with a value (as determined as therein provided) that equals or exceeds the aggregate amount of its then-outstanding letters of credit. In the case of an event of default under the Bilateral Facility with respect to a Bilateral Facility Participant, CEP may exercise certain remedies with respect to such Bilateral Facility Participant, including terminating its commitment to such Bilateral Facility Participant under the Bilateral Facility and taking certain actions with respect to the collateral pledged by such Bilateral Facility Participant (including the sale thereof). In the Facility Letter, each Bilateral Facility Participant makes, as to itself, representations and warranties that are customary for facilities of this type and severally agrees that it will comply with certain informational and other undertakings, including those regarding the delivery of quarterly and annual financial statements.
	Funds at Lloyd’s Letter of Credit Facilities
	Effective November 24, 2014, Renaissance Reinsurance and CEP entered into a Second Amended and Restated Pledge Agreement (the “Renaissance Reinsurance Pledge Agreement”) in respect of its letter of credit facility with CEP which is evidenced by the Master Agreement, dated as of April 29, 2009 (the “Renaissance Reinsurance Master Agreement”), which provides for the issuance and renewal of letters of credit which are used to support business written by Syndicate 1458. At December 31, 2014, letters of credit issued by CEP under the Renaissance Reinsurance Master Reimbursement Agreement were outstanding in the amount of $300.0 million and £70.0 million, respectively. Pursuant to the Renaissance Reinsurance Pledge Agreement, Renaissance Reinsurance has agreed to pledge to CEP at all times during the term of the Renaissance Reinsurance Master Agreement certain qualifying securities with a value (as determined as therein provided) that equals or exceeds the aggregate amount of the then-outstanding letters of credit issued under the Renaissance Reinsurance Master Agreement.
	Effective November 24, 2014, RenaissanceRe Specialty Risks and CEP entered into the Master Agreement (the “Specialty Risks Master Agreement” and, together with the Renaissance Reinsurance Master Agreement, the “Master Agreements”) which provides for the issuance and renewal by CEP for the account of RenaissanceRe Specialty Risks of letters of credit which are used to support business written by Syndicate 1458 and a related Pledge Agreement (the “Specialty Risks Pledge Agreement” and, together with the Renaissance Reinsurance Pledge Agreement, the “Pledge Agreements”). At December 31, 2014, letters of credit issued by CEP under the Specialty Risks Master Agreement were outstanding in the amount of $9.1 million. Pursuant to the Specialty Risks Pledge Agreement, RenaissanceRe Specialty Risks has agreed to pledge to CEP at all times during the term of the Specialty Risks Master Agreement certain qualifying securities with a value (as determined as therein provided) equal to the aggregate amount of the then-outstanding letters of credit issued under the Specialty Risks Master Agreement.
	Each of the Master Agreements and the Pledge Agreements contains representations, warranties and covenants that are customary for facilities of this type.
	Letters of Credit
	At December 31, 2014, the Company had total letters of credit outstanding under all facilities of $624.9 million.
	Renaissance Reinsurance is also party to a collateralized letter of credit and reimbursement agreement in the amount of $37.5 million that supports the Company’s Top Layer Re joint venture. Renaissance Reinsurance is obligated to make a mandatory capital contribution of up to $50.0 million in the event that a loss reduces Top Layer Re’s capital below a specified level.
	DaVinciRe Loan Agreement
	On March 30, 2011, DaVinciRe entered into a loan agreement with RenaissanceRe (the “Loan Agreement”) under which RenaissanceRe made a loan to DaVinciRe in the principal amount of $200.0 million on April 1, 2011. The loan matures on March 31, 2021 and interest on the loan is payable at a rate of three-month LIBOR plus 3.5% and is due at the end of each March, June, September and December, commencing on June 30, 2011. Under the terms of the Loan Agreement, DaVinciRe is required to maintain a debt to capital ratio of no greater than 0.40:1 and a net worth of no less than $500.0 million. At December 31, 2014, $100.0 million remained outstanding under the Loan Agreement. No additional amounts may be borrowed by DaVinciRe under the Loan Agreement.
	Interest Paid and Scheduled Debt Maturity
	Interest paid on the Company’s debt totaled $17.2 million for the year ended December 31, 2014 (2013 – $20.1 million, 2012 – $23.1 million).
	The following table sets forth the scheduled maturity of the Company’s aggregate amount of its debt obligation reflected on its consolidated balance sheet at December 31, 2014:
		2015	$	—
		2016	—
		2017	—
		2018	—
		2019	—
		After 2019	250,000
		Unamortized debt issuance expenses	(478		)
			$	249,522

Noncontrolling_Interests

Noncontrolling Interests	12 Months Ended
	Dec. 31, 2014
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest [Abstract]
Noncontrolling Interests	NONCONTROLLING INTERESTS
	A summary of the Company’s noncontrolling interests on its consolidated balance sheets is set forth below:
			2014			2013
		Redeemable noncontrolling interest - DaVinciRe	$	1,037,306		$	1,063,368
		Redeemable noncontrolling interest - Medici	94,402			36,492
		Redeemable noncontrolling interest	$	1,131,708		$	1,099,860
		Noncontrolling interest - Angus Fund	$	—		$	—
	A summary of the Company’s noncontrolling interests on its consolidated statements of operations is set forth below:
			2014			2013			2012
		Redeemable noncontrolling interest - DaVinciRe	$	149,817		$	150,581		$	147,499
		Redeemable noncontrolling interest - Medici	3,721			617			—
		Noncontrolling interest - Angus Fund	—			(54		)	541
		Net income (loss) attributable to noncontrolling interests	$	153,538		$	151,144		$	148,040
	Redeemable Noncontrolling Interest – DaVinciRe
	In October 2001, the Company formed DaVinciRe and DaVinci with other equity investors. RenaissanceRe owns a noncontrolling economic interest in DaVinciRe; however, because RenaissanceRe controls a majority of DaVinciRe’s outstanding voting rights, the consolidated financial statements of DaVinciRe are included in the consolidated financial statements of the Company. The portion of DaVinciRe’s earnings owned by third parties is recorded in the consolidated statements of operations as net income attributable to noncontrolling interests. The Company’s noncontrolling economic ownership in DaVinciRe was 23.4% at December 31, 2014 (2013 - 27.3%).
	DaVinciRe shareholders are party to a shareholders agreement (the “Shareholders Agreement”) which provides DaVinciRe shareholders, excluding RenaissanceRe, with certain redemption rights that enable each shareholder to notify DaVinciRe of such shareholder’s desire for DaVinciRe to repurchase up to half of such shareholder’s initial aggregate number of shares held, subject to certain limitations, such as limiting the aggregate of all share repurchase requests to 25% of DaVinciRe’s capital in any given year and satisfying all applicable regulatory requirements. If total shareholder requests exceed 25% of DaVinciRe’s capital, the number of shares repurchased will be reduced among the requesting shareholders pro rata, based on the amounts desired to be repurchased. Shareholders desiring to have DaVinci repurchase their shares must notify DaVinciRe before March 1 of each year. The repurchase price will be based on GAAP book value as of the end of the year in which the shareholder notice is given, and the repurchase will be effective as of such date. Payment will be made by April 1 of the following year, following delivery of the audited financial statements for the year in which the repurchase was effective. The repurchase price is subject to a true-up for development on outstanding loss reserves after settlement of all claims relating to the applicable years.
	2013
	During January 2013, DaVinciRe redeemed shares from certain DaVinciRe shareholders (including those who submitted redemption notices in advance of the March 1, 2012 annual redemption notice date, as discussed above) while certain other DaVinciRe shareholders purchased additional shares in DaVinciRe. The net redemption as a result of these transactions was $150.0 million. In connection with the redemptions, DaVinciRe retained a $20.5 million holdback. The Company’s noncontrolling economic ownership in DaVinciRe was 30.8% at December 31, 2012 and subsequent to the above transactions, the Company’s noncontrolling economic ownership in DaVinciRe increased to 32.9% effective January 1, 2013.
	Effective October 1, 2013, an existing third party shareholder sold a portion of its shares in DaVinciRe to a new third party shareholder.  In addition, effective October 1, 2013, the Company sold a portion of its shares of DaVinciRe to the same new third party shareholder.  The Company sold these shares for $77.4 million and subsequent to the above transactions, the Company’s noncontrolling economic ownership interest in DaVinciRe decreased, and was 27.3% at December 31, 2013.
	2014
	During January 2014, DaVinciRe redeemed a portion of its outstanding shares from all existing DaVinciRe shareholders, including RenaissanceRe, while a new DaVinciRe shareholder purchased shares in DaVinciRe. The net redemption as a result of these transactions was $300.0 million. In connection with the redemption, DaVinciRe retained a $60.0 million holdback. The Company’s noncontrolling economic ownership in DaVinciRe subsequent to these transactions was 26.5%, effective January 1, 2014. During February 2014, DaVinciRe paid $30.0 million of the $60.0 million holdback. There were no additional payments of the holdback during the remainder of 2014.
	Effective July 1, 2014, RenaissanceRe sold a portion of its shares of DaVinciRe to an existing third party shareholder. RenaissanceRe sold these shares for $38.9 million. The Company's ownership in DaVinciRe was 26.5% at June 30, 2014 and subsequent to the above transaction, its ownership interest in DaVinciRe decreased to 23.4% effective July 1, 2014.
	See “Note 23. Subsequent Events” for additional information related to DaVinciRe shareholder transactions which occurred subsequent to December 31, 2014.
	The Company expects its noncontrolling economic ownership in DaVinciRe to fluctuate over time.
	The activity in redeemable noncontrolling interest – DaVinciRe is detailed in the table below:
			2014			2013
		Balance – January 1	$	1,063,368		$	968,259
		Redemption of shares from redeemable noncontrolling interest	(224,455		)	(209,356		)
		Sale of shares to redeemable noncontrolling interest	48,576			153,884
		Comprehensive income:
		Net income attributable to redeemable noncontrolling interest	149,817			150,581
		Balance – December 31	$	1,037,306		$	1,063,368
	Redeemable Noncontrolling Interest - Medici
	Medici is an exempted company incorporated under the laws of Bermuda and its objective is to seek to invest substantially all of its assets in various insurance-based investment instruments that have returns primarily tied to property catastrophe risk. RenaissanceRe owns a noncontrolling economic interest in Medici; however, because RenaissanceRe controls all of Medici’s outstanding voting rights, the financial statements of Medici are included in the consolidated financial statements of the Company. The portion of Medici’s earnings owned by third parties is recorded in the consolidated statements of operations as net income attributable to noncontrolling interests. Any shareholder may redeem all or any portion of its shares as of the last day of any calendar month, upon at least 30 calendar days’ prior irrevocable written notice to Medici. As the participating, non-voting common shares of Medici have redemption features which are outside the control of the issuer, the portion related to the redeemable noncontrolling interest in Medici is recorded in the mezzanine section of the consolidated balance sheets of the Company.
	2013
	Prior to June 1, 2013, Medici was a wholly owned subsidiary of Fund Holdings, which in turn is a wholly owned subsidiary of RenaissanceRe. Subsequent to June 1, 2013, third-party investors subscribed for, and redeemed, an aggregate of $37.2 million and $1.3 million, respectively, of the participating, non-voting common shares of Medici. As a result of the third-party investments during the period from June 1, 2013 through December 31, 2013, the Company’s ownership in Medici was 73.9% at December 31, 2013.
	2014
	During 2014, third-party investors subscribed for and redeemed an aggregate of $57.3 million and $3.1 million, respectively, of the participating, non-voting common shares of Medici. As a result of these net subscriptions, the Company’s economic ownership in Medici decreased to 53.2%, effective December 31, 2014.
	The Company expects its ownership in Medici to fluctuate over time.
	The activity in redeemable noncontrolling interest – Medici is detailed in the table below:
			2014			2013
		Balance – January 1	$	36,492		$	—
		Redemption of shares from redeemable noncontrolling interest	(3,075		)	(1,325		)
		Sale of shares to redeemable noncontrolling interest	57,264			37,200
		Net income attributable to redeemable noncontrolling interest	3,721			617
		Balance – December 31	$	94,402		$	36,492
	Noncontrolling Interest - Angus Fund L.P. (the “Angus Fund”)
	In December 2010, REAL and RRCA, both formerly wholly owned subsidiaries of RenaissanceRe, formed the Angus Fund with other equity investors. The Angus Fund was formed to provide capital to and make investments in companies primarily in the heating oil and propane distribution industries and Angus was formed to provide commodity related risk management products to third party customers.
	As part of the agreement to sell REAL to Munich (see “Note 3. Discontinued Operations” for additional information), the former general partner of the Angus Fund, REAL, transferred its general partner ownership interest to RRV U.S. Holdings LLC (“RRV U.S.”), a wholly owned subsidiary of RenaissanceRe, representing a $55 thousand investment in the Angus Fund, or a 1.1% ownership interest, and RRCA, a former limited partner, transferred its limited partner ownership interest to RenTech U.S. Holdings LLC (“RenTech”), a wholly owned subsidiary of RenaissanceRe, representing a $2.0 million investment in the Angus Fund, or a 35.0% ownership interest. There was no gain or loss recognized on the above transactions.
	Effective December 1, 2013, both RRV U.S. and RenTech contributed their ownership interests in the Angus Fund to Angus for $2.3 million, in return for equity interests in Angus. The Company previously had an equity interest of 38.8% in Angus, and as a result of these transactions, its equity interest in Angus has increased to 42.5%. In addition, these transactions resulted in $1.7 million of additional goodwill related to the Company’s additional investment in Angus. During the first quarter of 2014, Angus raised additional capital from its existing third party investors. The Company did not participate in this capital raise and, as a result, the Company’s ownership interest in Angus is 40.4% at December 31, 2014. The Company records its equity investment in Angus one quarter in arrears.
	Prior to December 1, 2013, the Angus Fund met the definition of a VIE; therefore the Company evaluated its ownership in the Angus Fund to determine if it was the primary beneficiary. The Company had concluded it was the primary beneficiary of the Angus Fund as it had the power to direct, and had a more than insignificant economic interest in, the activities of the Angus Fund and as such, the financial position and results of operations of the Angus Fund were consolidated. The portion of the Angus Fund’s earnings owned by third parties was recorded in the consolidated statements of operations as net income attributable to noncontrolling interest. Effective December 1, 2013, the Company concluded that it no longer had the power to direct the activities, nor was it the primary beneficiary, of the Angus Fund and as a result, it was deconsolidated. The Company’s equity investment in Angus is recorded under investments in other ventures, under equity method on its consolidated balance sheets. See “Note. 5 Investments” for additional information related to the Company’s investments in other ventures, under equity method.
	The activity in noncontrolling interest is detailed in the table below:
			2014			2013
		Balance – January 1	$	—		$	3,991
		Adjustment of ownership interest	—			(3,709		)
		Net loss attributable to noncontrolling interest	—			(54		)
		Dividends on common shares	—			(228		)
		Balance – December 31	$	—		$	—

Variable_Interest_Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	VARIABLE INTEREST ENTITIES
	Upsilon Fund
	Effective November 13, 2014, the Company incorporated Upsilon Fund, an exempted Bermuda limited segregated accounts company. Upsilon Fund was formed to provide a fund structure through which third party investors can invest in reinsurance risk managed by the Company. As a segregated accounts company, Upsilon Fund is permitted to establish segregated accounts to invest in and hold identified pools of assets and liabilities. Each pool of assets and liabilities in each segregated account is ring-fenced from any claims from the creditors of Upsilon Fund’s general account and from the creditors of other segregated accounts within Upsilon Fund. Third party investors purchase redeemable, non voting preference shares linked to specific segregated accounts of Upsilon Fund and own 100% of these shares.
	Upsilon Fund is considered a VIE as the voting rights of the equity investors are not proportionate with the respective obligation to absorb expected losses or right to receive expected residual returns. The Company does not have the obligation to absorb the losses, nor the right to receive the benefits, in accordance with the accounting guidance, that could be significant to Upsilon Fund. However the Company does have the power over the activities that most significantly impact the economic performance of Upsilon Fund. Since the Company does not meet both criteria noted above, the Company is not the primary beneficiary of Upsilon Fund, and accordingly, does not consolidate Upsilon Fund. The Company has not provided any financial or other support to Upsilon Fund that was not contractually required to be provided.
	Upsilon RFO
	Effective January 1, 2013, the Company formed and launched Upsilon RFO, a managed joint venture, and a Bermuda domiciled SPI, to provide additional capacity to the worldwide aggregate and per-occurrence retrocessional property catastrophe excess of loss market.
	The shareholders (other than the Class A shareholder) participate in substantially all of the profits or losses of Upsilon RFO while their shares remain outstanding. The shareholders (other than the Class A shareholder) indemnify Upsilon RFO against losses relating to insurance risk and therefore these shares have been accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance. Both Upsilon RFO and the insurance participation are managed by RUM in return for an expense override and profit commission.
	Upsilon RFO is considered a VIE as it has insufficient equity capital to finance its activities without additional financial support. The Company is the primary beneficiary of Upsilon RFO as it: (i) has the power over the activities that most significantly impact the economic performance of Upsilon RFO and (ii) has the obligation to absorb losses, and right to receive benefits, in accordance with the accounting guidance, that could be significant to Upsilon RFO. As a result, the Company consolidates Upsilon RFO and all significant inter-company transactions have been eliminated. The Company has not provided financial or other support to Upsilon RFO that was not contractually required to be provided.
	2013
	Original business was written directly by Upsilon RFO and included $53.5 million of gross premiums written incepting January 1, 2013 under fully-collateralized reinsurance contracts. In conjunction with the formation and launch of Upsilon RFO, $61.0 million of Upsilon RFO non-voting Class B shares were sold to unaffiliated third party investors. Additionally, $76.4 million of the non-voting Class B shares were acquired by the Company, representing a 55.6% participation in the original risks assumed by Upsilon RFO effective January 1, 2013. In addition, another third party investor supplied $17.5 million of capital through an insurance contract with the Company related to Upsilon RFO’s reinsurance portfolio. Inclusive of the insurance contract, the Company had a 42.9% participation in the original risks assumed by Upsilon RFO effective January 1, 2013.
	On July 1, 2013, the Company sold a portion of its shares of Upsilon RFO to a new third party shareholder for $25.0 million. The Company’s participation in the original risks assumed by Upsilon RFO prior to January 1, 2014 was 25.8%, inclusive of the related insurance contract, effective December 31, 2013.
	Original business written directly by Upsilon RFO and incepting during 2013 has expired, and the associated non-voting Class B share capital contributed by unaffiliated third party investors and the Company has been settled in full. No additional business or non-voting Class B share capital remains outstanding related to original business incepted during 2013.
	2014
	In conjunction with risks incepting during the first quarter of 2014, $172.4 million of Upsilon RFO non-voting preference shares were sold to unaffiliated third-party investors.  Additionally, $109.7 million of the non-voting preference shares were acquired by the Company, representing a 38.9% participation in the risks assumed by Upsilon RFO incepting during the first quarter of 2014.  In addition, another third party investor supplied $15.0 million of capital through an insurance contract with the Company related to Upsilon RFO’s reinsurance portfolio.  Inclusive of the insurance contract, the Company has a 33.6% participation in the original risks assumed by Upsilon RFO in conjunction with risks incepting during the first quarter of 2014.
	In conjunction with risks incepting during the second quarter of 2014, $43.1 million of Upsilon RFO non-voting preference shares were sold to unaffiliated third-party investors.  Additionally, $13.5 million of the non-voting preference shares were acquired by the Company, representing a 23.9% participation in the risks assumed by Upsilon RFO incepting during the second quarter of 2014.  In addition, another third party investor supplied $5.0 million of capital through an insurance contract with the Company related to Upsilon RFO’s reinsurance portfolio.  Inclusive of the insurance contract, the Company has a 15.0% participation in the original risks assumed by Upsilon RFO in conjunction with risks incepting during the second quarter of 2014.
	At December 31, 2014, the Company’s consolidated balance sheet included total assets and total liabilities of Upsilon RFO of $621.3 million and $621.3 million, respectively (2013 - $474.2 million and $474.2 million, respectively), including $135.7 million of capital raised from third party investors and received by Upsilon RFO prior to December 31, 2014 for risks incepting during the first quarter of 2015 (2013 - $156.3 million of capital raised from third party investors and received by Upsilon RFO prior to December 31, 2013 for risks incepted during the first quarter of 2014).
	Inclusive of all capital raised for risks incepting during 2014, the Company has a 30.5% participation in the original risks assumed by Upsilon RFO for the period from January 1, 2014 through December 31, 2014.
	See “Note 23. Subsequent Events” for additional information related to Upsilon RFO transactions which occurred subsequent to December 31, 2014.
	Mona Lisa Re Ltd. (“Mona Lisa Re”)
	On March 14, 2013, Mona Lisa Re was licensed as a Bermuda domiciled SPI to provide reinsurance capacity to subsidiaries of RenaissanceRe, namely Renaissance Reinsurance and DaVinci, through reinsurance agreements which will be collateralized and funded by Mona Lisa Re through the issuance of one or more series of principal-at-risk variable rate notes (“Notes”) to third-party investors.
	Upon issuance of a series of Notes by Mona Lisa Re, all of the proceeds from the issuance are expected to be deposited into collateral accounts, separated by series, to fund any potential obligation under the reinsurance agreements entered into with Renaissance Reinsurance and/or DaVinci underlying such series of Notes. The outstanding principal amount of each series of Notes generally will be returned to holders of such Notes upon the expiration of the risk period underlying such Notes, unless an event occurs which causes a loss under the applicable series of Notes, in which case the amount returned will be reduced by such noteholder’s pro rata share of such loss, as specified in the applicable governing documents of such Notes. In addition, holders of Notes are generally entitled to interest payments, payable quarterly, as determined by the applicable governing documents of each series of Notes.
	The Company concluded that Mona Lisa Re meets the definition of a VIE as it does not have sufficient equity capital to finance its activities. Therefore, the Company evaluated its relationship with Mona Lisa Re and concluded it does not have a variable interest in Mona Lisa Re. As a result, the financial position and results of operations of Mona Lisa Re are not consolidated by the Company. At December 31, 2014, the total assets and total liabilities of Mona Lisa Re were $184.0 million and $184.0 million, respectively (2013 - $209.6 million and $209.6 million, respectively).
	The only transactions related to Mona Lisa Re that are recorded in the Company’s consolidated financial statements are the ceded reinsurance agreements entered into by Renaissance Reinsurance and DaVinci which are accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance. Renaissance Reinsurance and DaVinci have together entered into ceded reinsurance contracts with Mona Lisa Re with gross premiums ceded of $7.4 million and $5.1 million, respectively, during 2014 (2013 - $9.2 million and $6.5 million, respectively). In addition, Renaissance Reinsurance and DaVinci recognized ceded premiums earned related to the ceded reinsurance contracts with Mona Lisa Re of $8.2 million and $5.7 million, respectively, during 2014 (2013 - $4.8 million and $3.5 million, respectively).

Shareholders_Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Shareholders' Equity	SHAREHOLDERS’ EQUITY
	The aggregate authorized capital of RenaissanceRe is 325 million shares consisting of 225 million common shares and 100 million preference shares. The following table is a summary of changes in common shares issued and outstanding:
		Year ended December 31,	2014		2013		2012
		(thousands of shares)
		Issued and outstanding shares – January 1	43,646		45,542		51,543
		Repurchase of shares	(5,355	)	(2,451	)	(6,399	)
		Exercise of options and issuance of restricted stock awards	151		555		398
		Issued and outstanding shares – December 31	38,442		43,646		45,542
	The Board of Directors of RenaissanceRe declared, and RenaissanceRe paid, a dividend of $0.29 per common share to shareholders of record on March 14, June 13, September 15 and December 15, 2014, respectively. Dividends declared and paid on common shares amounted to $1.16 per common share for the year ended December 31, 2014 (2013 - $1.12, 2012 - $1.08), or $45.9 million on all common shares outstanding (2013 - $49.3 million, 2012 - $53.4 million).
	The Company’s share repurchase program may be effected from time to time, depending on market conditions and other factors, through open market purchases and privately negotiated transactions. Unless terminated earlier by resolution of RenaissanceRe’s Board of Directors, the program will expire when the Company has repurchased the full value of the shares authorized. The Company’s decision to repurchase common shares will depend on, among other matters, the market price of the common shares and the capital requirements of the Company. During the year ended December 31, 2014, the Company repurchased an aggregate of 5.4 million shares in open market transactions at an aggregate cost of $514.2 million, and at an average share price of $96.04. On November 13, 2014, RenaissanceRe’s Board of Directors approved a renewal of the authorized share repurchase program to an aggregate amount of $500.0 million. At December 31, 2014, $500.0 million remained available for repurchase under the Board authorized share repurchase program.
	In March 2004, RenaissanceRe raised $250.0 million through the issuance of 10 million Series C Preference Shares at $25 per share; in December 2006, RenaissanceRe raised $300.0 million through the issuance of 12 million Series D Preference Shares at $25 per share; and in May 2013, RenaissanceRe raised $275.0 million through the issuance of 11 million Series E Preference Shares at $25 per share. Offering expenses of $9.1 million related to the issuance of the Series E Preference Shares have been included in additional paid in capital on the Company’s consolidated statements of changes in shareholders’ equity. On December 27, 2012, the Company redeemed 6 million Series D Preference Shares for $150.0 million plus accrued and unpaid dividends thereon. Following the redemption, 6 million Series D Preference Shares remained outstanding. The proceeds of the issuance of the Series E Preference Shares were used to redeem the remaining 6 million outstanding Series D Preference Shares and 5 million of the outstanding Series C Preference Shares, as discussed below.
	The Series E Preference Shares and the remaining Series C Preference Shares may be redeemed at $25 per share plus certain dividends at RenaissanceRe’s option on or after June 1, 2018 and March 23, 2009, respectively. Dividends on the Series C Preference Shares are cumulative from the date of original issuance and are payable quarterly in arrears at 6.08% per annum, when, if, and as declared by the Board of Directors. Dividends on the Series E Preference Shares will be payable from the date of original issuance on a non-cumulative basis, only when, as and if declared by the Board of Directors, quarterly in arrears at 5.375% per annum. Unless certain dividend payments are made on the preference shares, RenaissanceRe will be restricted from paying any dividends on its common shares. The preference shares have no stated maturity and are not convertible into any other securities of RenaissanceRe. Generally, the preference shares have no voting rights. Whenever dividends payable on the preference shares are in arrears (whether or not such dividends have been earned or declared) in an amount equivalent to dividends for six full dividend periods (whether or not consecutive), the holders of the preference shares, voting as a single class regardless of class or series, will have the right to elect two directors to the Board of Directors of RenaissanceRe.
	In May 2013, RenaissanceRe announced a mandatory redemption of the remaining 6 million of its outstanding Series D Preference Shares and on June 27, 2013 RenaissanceRe redeemed the remaining 6 million Series D Preference Shares called for redemption for $150.0 million million plus accrued and unpaid dividends thereon. Following the redemption, no Series D Preference Shares remain outstanding. In addition, in May 2013, RenaissanceRe announced a mandatory partial redemption of 5 million of its outstanding Series C Preference Shares. The partial redemption was allocated by random lottery in accordance with the Depository Trust Company’s rules and procedures and on June 27, 2013 RenaissanceRe redeemed the 5 million Series C Preference Shares called for redemption for $125.0 million plus accrued and unpaid dividends thereon. Following the redemption, 5 million Series C Preference Shares remain outstanding.
	During the year ended December 31, 2014, RenaissanceRe declared and paid $22.4 million in preference share dividends (2013 - $24.9 million, 2012 - $34.9 million).

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE
	The following table sets forth the computation of basic and diluted earnings per common share:
		Year ended December 31,	2014			2013			2012
		(thousands of shares)
		Numerator:
		Net income available to RenaissanceRe common shareholders	$	510,337		$	665,676		$	566,014
		Amount allocated to participating common shareholders (1)	(6,760		)	(9,520		)	(8,973		)
		Net income allocated to RenaissanceRe common shareholders	$	503,577		$	656,156		$	557,041
		Denominator:
		Denominator for basic income per RenaissanceRe common share - weighted average common shares	39,425			43,349			48,873
		Per common share equivalents of employee stock options and restricted shares	543			779			730
		Denominator for diluted income per RenaissanceRe common share - adjusted weighted average common shares and assumed conversions	39,968			44,128			49,603
		Basic income per RenaissanceRe common share	$	12.77		$	15.14		$	11.4
		Diluted income per RenaissanceRe common share	$	12.6		$	14.87		$	11.23
	-1	Represents earnings attributable to holders of unvested restricted shares issued under the Company’s 2001 Stock Incentive Plan and the Non-Employee Director Stock Incentive Plan.

Related_Party_Transactions_and

Related Party Transactions and Major Customers	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions and Major Customers	RELATED PARTY TRANSACTIONS AND MAJOR CUSTOMERS
	The Company has equity interests in the Tower Hill Companies as described in “Note 5. Investments”. The Company has entered into reinsurance agreements with certain subsidiaries and affiliates of Tower Hill and has also entered into reinsurance agreements with respect to business produced by the Tower Hill Companies. For the year ended December 31, 2014, the Company recorded $40.0 million (2013 - $46.7 million, 2012 - $41.1 million) of gross premium written assumed from Tower Hill and its subsidiaries and affiliates. Gross premiums earned totaled $41.9 million (2013 - $44.9 million, 2012 - $36.1 million) and expenses incurred were $4.7 million (2013 - $5.3 million, 2012 - $3.9 million) for the year ended December 31, 2014. The Company had a net related outstanding receivable balance of $18.3 million as of December 31, 2014 (2013 - $20.2 million). During 2014, the Company assumed net claims and claims expenses of $3.6 million (2013 - $4.1 million, 2012 - $4.0 million) and, as of December 31, 2014, had a net reserve for claims and claim expenses of $40.3 million (2013 - $37.1 million). In addition, the Company received distributions of $10.0 million from THIG during 2014 (2013 - $9.8 million).
	As a result of the transactions described in “Note 10. Noncontrolling Interests”, the Company has cumulatively invested $10.5 million in Angus, representing a 40.4% equity interest, which is accounted for under the equity method of accounting. Angus primarily provides commodity related risk management products to third party customers. For the year ended December 31, 2014, the Company generated other income of $Nil (2013 - $5.0 million, 2012 - $7.9 million) associated with Angus related transactions which is reflected in the Company’s discontinued operations with respect to REAL.
	During 2014, the Company received distributions from Top Layer Re of $Nil (2013 - $Nil, 2012 - $Nil), and a management fee of $2.8 million (2013 - $3.8 million, 2012 - $4.1 million). The management fee reimburses the Company for services it provides to Top Layer Re.
	During 2014, the Company received 89.2% of its aggregate Catastrophe Reinsurance and Specialty Reinsurance segments’ gross premiums written (2013 - 88.2%, 2012 - 84.6%) from three brokers. Subsidiaries and affiliates of AON Benfield, Marsh Inc., and the Willis Group accounted for approximately 56.1%, 21.2% and 11.9%, respectively, of gross premiums written for the aggregate of the Catastrophe Reinsurance and Specialty Reinsurance segments in 2014 (2013 - 48.6%, 22.7% and 16.9%, respectively, 2012 - 51.5%, 21.4% and 11.7%, respectively).

Taxation

Taxation	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Taxation	TAXATION
	Under current Bermuda law, RenaissanceRe and its Bermuda subsidiaries are not subject to any income or capital gains taxes. In the event that such taxes are imposed, RenaissanceRe and its Bermuda subsidiaries would be exempted from any such tax until March 2035 pursuant to the Bermuda Exempted Undertakings Tax Protection Act 1966, and Amended Acts of 1987 and 2011, respectively.
	RenRe North America Holdings Inc. (“RenRe North America”) and its subsidiaries are subject to income taxes imposed by U.S. federal and state authorities and file a consolidated U.S. federal income tax return. Should the U.S. subsidiaries pay a dividend to RenaissanceRe, withholding taxes would apply to the extent of current year or accumulated earnings and profits. The Company also has operations in Ireland, the U.K., and Singapore which are subject to income taxes imposed by the respective jurisdictions in which they operate.
	The Company is not subject to income taxation other than as stated above.  There can be no assurance that there will not be changes in applicable laws, regulations or treaties, which might require the Company to change the way it operates or become subject to taxation.
	The following is a summary of the Company’s income from continuing operations before taxes allocated between domestic and foreign operations:
		Year ended December 31,	2014			2013			2012
		Domestic
		Bermuda	$	701,476		$	873,103		$	795,378
		Foreign
		United Kingdom	(3,166		)	(12,678		)	(15,404		)
		U.S.	(10,977		)	(20,019		)	(16,467		)
		Ireland	1,549			1,855			3,318
		Singapore	(2,018		)	(1,223		)	13
		Income from continuing operations before taxes	$	686,864		$	841,038		$	766,838
	Income tax (expense) benefit is comprised as follows:
		Year ended December 31, 2014	Current			Deferred			Total
		Total income tax (expense) benefit	$	(699	)	$	91		$	(608	)
		Year ended December 31, 2013
		Total income tax (expense) benefit	$	(2,005	)	$	313		$	(1,692	)
		Year ended December 31, 2012
		Total income tax (expense) benefit	$	(1,667	)	$	254		$	(1,413	)
	The Company’s expected income tax provision computed on pre-tax income at the weighted average tax rate has been calculated as the sum of the pre-tax income in each jurisdiction multiplied by that jurisdiction’s applicable statutory tax rate. Statutory tax rates of 0.0%, 35.0%, 12.5%, 21.5% and 17.0% have been used for Bermuda, the U.S., Ireland, the U.K. and Singapore, respectively.
	The Company’s effective income tax rate, which it calculates as income tax expense divided by net income before taxes, may fluctuate significantly from period to period depending on the geographic distribution of pre-tax net income in any given period between different jurisdictions with comparatively higher tax rates and those with comparatively lower tax rates. The geographic distribution of pre-tax income (loss) can vary significantly between periods due to, but not limited to, the following factors: the business mix of net premiums written and earned; the geographic location, the size and the nature of net claims and claim expenses incurred; the amount and geographic location of operating expenses, net investment income, net realized and unrealized gains (losses) on investments; outstanding debt and related interest expense; and the amount of specific adjustments to determine the income tax basis in each of the Company’s operating jurisdictions.  In addition, a significant portion of the Company’s gross and net premiums are currently written and earned in Bermuda, which does not have a corporate income tax, including the majority of the Company’s catastrophe business, which can result in significant volatility to its pre-tax income (loss) in any given period.
	A reconciliation of the difference between the provision for income taxes and the expected tax provision at the weighted average tax rate is as follows:
		Year ended December 31,	2014			2013			2012
		Expected income tax benefit	$	4,725		$	9,930		$	8,889
		Change in valuation allowance	(5,554		)	(8,574		)	(6,212		)
		Other	221			(3,048		)	(4,090		)
		Income tax expense	$	(608	)	$	(1,692	)	$	(1,413	)
	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities are presented below:
		At December 31,	2014			2013
		Deferred tax assets
		Tax loss and credit carryforwards	$	37,933		$	34,429
		Deferred interest expense	17,066			12,608
		Accrued expenses	3,413			1,096
		Amortization and depreciation	1,686			1,730
		Deferred underwriting results	1,586			1,873
		Investments	290			4,694
			61,974			56,430
		Deferred tax liabilities
		Amortization and depreciation	(54		)	(155		)
			(54		)	(155		)
		Net deferred tax asset before valuation allowance	61,920			56,275
		Valuation allowance	(61,660		)	(56,106		)
		Net deferred tax asset (liability)	$	260		$	169
	During 2014, the Company recorded a net increase to the valuation allowance of $5.6 million (2013 – increase of $21.0 million, 2012 – increase of $6.2 million). The Company’s net deferred tax asset primarily relates to net operating loss carryforwards and GAAP versus tax basis accounting differences relating to interest expense, underwriting results, accrued expenses and investments. The Company’s U.S. operations generated a cumulative GAAP taxable loss for the three year periods ended December 31, 2014 and 2013. Accordingly, the Company believes that it is more likely than not that the U.S. net deferred tax asset will not be realized and as a result has provided a full valuation allowance against its U.S. net deferred tax asset. In addition, a valuation allowance has been provided against deferred tax assets in Ireland, the U.K., and Singapore. These deferred tax assets relate primarily to net operating loss carryforwards and deferred underwriting results.
	In the U.S., the Company has net operating loss carryforwards of $65.0 million. Under applicable law, the U.S. net operating loss carryforwards will begin to expire in 2031. In Ireland, the Company has net operating loss carryforwards of $10.8 million. In the U.K., the Company has net operating loss carryforwards of $45.5 million. In Singapore, the Company has net operating loss carryforwards of $3.9 million. Under applicable law, the Irish, U.K. and Singapore net operating losses can be carried forward for an indefinite period.
	The Company had a net payment for U.S. federal, Irish, U.K. and Singapore income taxes of $1.1 million for the year ended 2014 (2013 – net payment of $1.2 million, 2012 – net refund of $13.2 million).
	The Company has unrecognized tax benefits of $Nil as of December 31, 2014 (2013 – $Nil). Interest and penalties related to unrecognized tax benefits would be recognized in income tax expense.  At December 31, 2014, interest and penalties accrued on unrecognized tax benefits were $Nil. Income tax returns filed for tax years 2009 through 2013, 2010 through 2013, 2013 and 2012 through 2013, are open for examination by the Internal Revenue Service, Irish tax authorities, U.K. tax authorities, and Singapore tax authorities, respectively. The Company does not expect the resolution of these open years to have a significant impact on its results from operations and financial condition.

Segment_Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2014
Segment Reporting, Measurement Disclosures [Abstract]
Segment Reporting	SEGMENT REPORTING
	The Company has the following reportable segments: (1) Catastrophe Reinsurance, which includes catastrophe reinsurance and certain property catastrophe joint ventures managed by the Company’s ventures unit; (2) Specialty Reinsurance, which includes specialty reinsurance and certain specialty joint ventures managed by the Company’s ventures unit; and (3) Lloyd’s, which includes reinsurance and insurance business written through Syndicate 1458. RenaissanceRe CCL, an indirect wholly owned subsidiary of RenaissanceRe, is the sole corporate member of Syndicate 1458.
	The financial results of the Company’s strategic investments, former Insurance segment, discontinued operations related to REAL and current noncontrolling interests are included in the Other category of the Company’s segment results. Also included in the Other category of the Company’s segment results are the Company’s investments in other ventures, investments unit, corporate expenses and capital servicing costs.
	The Company does not manage its assets by segment; accordingly, net investment income and total assets are not allocated to the segments.
	A summary of the significant components of the Company’s revenues and expenses is as follows:
		Twelve months ended December 31, 2014	Catastrophe Reinsurance			Specialty Reinsurance			Lloyd’s			Other			Total
		Gross premiums written (1)	$	933,969		$	346,638		$	269,656		$	309		$	1,550,572
		Net premiums written	$	541,608		$	295,855		$	230,429		$	344		$	1,068,236
		Net premiums earned	$	590,845		$	253,537		$	217,666		$	368		$	1,062,416
		Net claims and claim expenses incurred	1,757			88,502			113,825			(6,137		)	197,947
		Acquisition expenses	43,161			60,936			46,927			(6,548		)	144,476
		Operational expenses	95,851			43,370			51,115			303			190,639
		Underwriting income	$	450,076		$	60,729		$	5,799		$	12,750		529,354
		Net investment income										124,316			124,316
		Net foreign exchange gains										6,260			6,260
		Equity in earnings of other ventures										26,075			26,075
		Other loss										(423		)	(423		)
		Net realized and unrealized gains on investments										41,433			41,433
		Corporate expenses										(22,987		)	(22,987		)
		Interest expense										(17,164		)	(17,164		)
		Income before taxes and noncontrolling interests													686,864
		Income tax expense										(608		)	(608		)
		Net income attributable to noncontrolling interests										(153,538		)	(153,538		)
		Dividends on preference shares										(22,381		)	(22,381		)
		Net income available to RenaissanceRe common shareholders													$	510,337
		Net claims and claim expenses incurred – current accident year	$	67,268		$	144,411		$	130,066		$	—		$	341,745
		Net claims and claim expenses incurred – prior accident years	(65,511		)	(55,909		)	(16,241		)	(6,137		)	(143,798		)
		Net claims and claim expenses incurred – total	$	1,757		$	88,502		$	113,825		$	(6,137	)	$	197,947
		Net claims and claim expense ratio – current accident year	11.4		%	57		%	59.8		%	—		%	32.2		%
		Net claims and claim expense ratio – prior accident years	(11.1		)%	(22.1		)%	(7.5		)%	(1,667.7		)%	(13.6		)%
		Net claims and claim expense ratio – calendar year	0.3		%	34.9		%	52.3		%	(1,667.7		)%	18.6		%
		Underwriting expense ratio	23.5		%	41.1		%	45		%	(1,697.0		)%	31.6		%
		Combined ratio	23.8		%	76		%	97.3		%	(3,364.7		)%	50.2		%
	(1) Included in gross premiums written in the Other category is inter-segment gross premiums written of $0.3 million.
		Twelve months ended December 31, 2013	Catastrophe Reinsurance			Specialty Reinsurance			Lloyd’s			Other			Total
		Gross premiums written (1)	$	1,120,379		$	259,489		$	226,532		$	(988	)	$	1,605,412
		Net premiums written	$	753,078		$	248,562		$	201,697		$	610		$	1,203,947
		Net premiums earned	$	723,705		$	214,306		$	176,029		$	586		$	1,114,626
		Net claims and claim expenses incurred	7,908			67,236			95,693			450			171,287
		Acquisition expenses	49,161			41,538			34,823			(21		)	125,501
		Operational expenses	108,130			31,780			50,540			655			191,105
		Underwriting income (loss)	$	558,506		$	73,752		$	(5,027	)	$	(498	)	626,733
		Net investment income										208,028			208,028
		Net foreign exchange gains										1,917			1,917
		Equity in earnings of other ventures										23,194			23,194
		Other loss										(2,359		)	(2,359		)
		Net realized and unrealized gains on investments										35,076			35,076
		Corporate expenses										(33,622		)	(33,622		)
		Interest expense										(17,929		)	(17,929		)
		Income from continuing operations before taxes and noncontrolling interests													841,038
		Income tax expense										(1,692		)	(1,692		)
		Income from discontinued operations										2,422			2,422
		Net income attributable to noncontrolling interests										(151,144		)	(151,144		)
		Dividends on preference shares										(24,948		)	(24,948		)
		Net income available to RenaissanceRe common shareholders													$	665,676
		Net claims and claim expenses incurred – current accident year	$	109,945		$	101,347		$	103,949		$	—		$	315,241
		Net claims and claim expenses incurred – prior accident years	(102,037		)	(34,111		)	(8,256		)	450			(143,954		)
		Net claims and claim expenses incurred – total	$	7,908		$	67,236		$	95,693		$	450		$	171,287
		Net claims and claim expense ratio – current accident year	15.2		%	47.3		%	59.1		%	—		%	28.3		%
		Net claims and claim expense ratio – prior accident years	(14.1		)%	(15.9		)%	(4.7		)%	76.8		%	(12.9		)%
		Net claims and claim expense ratio – calendar year	1.1		%	31.4		%	54.4		%	76.8		%	15.4		%
		Underwriting expense ratio	21.7		%	34.2		%	48.5		%	108.2		%	28.4		%
		Combined ratio	22.8		%	65.6		%	102.9		%	185		%	43.8		%
	(1) Included in gross premiums written in the Other category is inter-segment gross premiums written of $(1.0) million.
	Year ended December 31, 2012	Catastrophe Reinsurance			Specialty Reinsurance			Lloyd’s			Other			Total
	Gross premiums written (1)	$	1,182,207		$	209,887		$	159,987		$	(490	)	$	1,551,591
	Net premiums written	$	766,035		$	201,552		$	135,131		$	(61	)	$	1,102,657
	Net premiums earned	$	781,738		$	164,685		$	122,968		$	(36	)	$	1,069,355
	Net claims and claim expenses incurred	165,209			76,813			80,242			2,947			325,211
	Acquisition expenses	66,665			23,826			22,864			187			113,542
	Operational expenses	103,811			29,124			45,680			536			179,151
	Underwriting income (loss)	$	446,053		$	34,922		$	(25,818	)	$	(3,706	)	451,451
	Net investment income										165,725			165,725
	Net foreign exchange gains										5,319			5,319
	Equity in earnings of other ventures										23,238			23,238
	Other loss										(2,120		)	(2,120		)
	Net realized and unrealized gains on investments										163,121			163,121
	Net other-than-temporary impairments										(343		)	(343		)
	Corporate expenses										(16,456		)	(16,456		)
	Interest expense										(23,097		)	(23,097		)
	Income from continuing operations before taxes													766,838
	Income tax expense										(1,413		)	(1,413		)
	Loss from discontinued operations										(16,476		)	(16,476		)
	Net income attributable to noncontrolling interests										(148,040		)	(148,040		)
	Dividends on preference shares										(34,895		)	(34,895		)
	Net income attributable to RenaissanceRe common shareholders													$	566,014
	Net claims and claim expenses incurred – current accident year	$	275,777		$	110,959		$	96,444		$	—		$	483,180
	Net claims and claim expenses incurred – prior accident years	(110,568		)	(34,146		)	(16,202		)	2,947			(157,969		)
	Net claims and claim expenses incurred – total	$	165,209		$	76,813		$	80,242		$	2,947		$	325,211
	Net claims and claim expense ratio – current accident year	35.3		%	67.4		%	78.4		%	—		%	45.2		%
	Net claims and claim expense ratio – prior accident years	(14.2		)%	(20.8		)%	(13.1		)%	(8,186.1		)%	(14.8		)%
	Net claims and claim expense ratio – calendar year	21.1		%	46.6		%	65.3		%	(8,186.1		)%	30.4		%
	Underwriting expense ratio	21.8		%	32.2		%	55.7		%	(2,008.3		)%	27.4		%
	Combined ratio	42.9		%	78.8		%	121		%	(10,194.4		)%	57.8		%
(1) Included in gross premiums written in the Other category is inter-segment gross premiums written of $0.5 million.
The following is a summary of the Company’s gross premiums written allocated to the territory of coverage exposure:
	Year ended December 31,	2014			2013			2012
	Catastrophe Reinsurance
	U.S. and Caribbean	$	573,696		$	782,211		$	857,740
	Worldwide	157,674			99,179			81,595
	Worldwide (excluding U.S.) (1)	123,476			146,048			139,265
	Japan	31,484			39,060			43,238
	Europe	25,353			25,659			37,113
	Australia and New Zealand	20,807			22,460			18,578
	Other	1,479			5,762			4,678
	Total Catastrophe Reinsurance	933,969			1,120,379			1,182,207
	Specialty Reinsurance
	U.S. and Caribbean	169,045			91,203			69,070
	Worldwide	161,329			151,879			96,081
	Australia and New Zealand	6,898			12,068			28,307
	Worldwide (excluding U.S.) (1)	7,506			1,661			—
	Europe	460			2,612			16,429
	Other	1,400			66			—
	Total Specialty Reinsurance	346,638			259,489			209,887
	Lloyd’s
	U.S. and Caribbean	120,066			88,535			57,332
	Worldwide	118,190			104,249			75,132
	Worldwide (excluding U.S.) (1)	13,655			8,071			6,064
	Europe	7,609			14,763			14,456
	Australia and New Zealand	2,907			2,948			2,152
	Other	7,229			7,966			4,851
	Total Lloyd’s	269,656			226,532			159,987
	Other category (2)	309			(988		)	(490		)
	Total gross premiums written	$	1,550,572		$	1,605,412		$	1,551,591
-1	The category “Worldwide (excluding U.S.)” consists of contracts that cover more than one geographic region (other than the U.S.). The exposure in this category for gross premiums written to date is predominantly from Europe and Japan.
-2	The Other category consists of contracts that are primarily exposed to U.S. risks and includes inter-segment gross premiums written of $0.3 million for the year ended December 31, 2014 (2013 - $(1.0) million, 2012 - $(0.5) million).

Stock_Incentive_Compensation_a

Stock Incentive Compensation and Employee Benefit Plans	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Incentive Compensation and Employee Benefit Plans	STOCK INCENTIVE COMPENSATION AND EMPLOYEE BENEFIT PLANS
	2001 Stock Incentive Plan and Non-Employee Director Stock Incentive Plan
	The Company has a stock incentive plan (the “2001 Stock Incentive Plan”) under which employees of RenaissanceRe and its subsidiaries may be granted stock options and restricted stock awards. A stock option award under the Company’s 2001 Stock Incentive Plan allows for the purchase of RenaissanceRe Common Shares at a price that is equal to the fair market value of RenaissanceRe Common Shares as of the grant effective date. Options to purchase RenaissanceRe Common Shares are granted periodically by the Board of Directors, generally vest over four years and generally expire 10 years from the date of grant. Restricted common shares are granted periodically by the Board of Directors and generally vest ratably over a four year period. The Company has also established a Non-Employee Director Stock Incentive Plan to issue stock options and shares of restricted stock to RenaissanceRe’s non-employee directors. The Company’s 2001 Stock Incentive Plan also allows for the issuance of share-based awards, the issuance of restricted common shares and the issuance of shares tendered in connection with option exercises. For purposes of determining the number of shares reserved for issuance under the 2001 Stock Plan, shares tendered to or withheld by the Company in connection with certain option exercises will again be available for issuance. The 2001 Stock Incentive Plan expires on February 6, 2016.
	Premium Option Plan
	In August 2004, RenaissanceRe’s shareholders approved the 2004 Stock Option Incentive Plan (the “Premium Option Plan”) under which 6.0 million common shares were reserved for issuance upon the exercise of options granted under the Premium Option Plan. On August 15, 2007, the Company terminated the Premium Option Plan, such that no further option grants will be made thereunder. However, options outstanding at the time of the termination will, unless otherwise subsequently amended pursuant to the terms of the Premium Option Plan, remain outstanding and unmodified until they expire, subject to the terms of the Premium Option Plan and any applicable award agreement. The Premium Option Plan provides for, among other things, mandatory premium pricing such that options can generally only be issued thereunder with a strike price at a minimum of 150% of the fair market value on the date of grant, minimum five year cliff vesting (subject to waiver by the compensation committee of the Board of Directors), and no discretionary repricing.  The Premium Option Plan includes a dividend protection feature that reduces the strike price for extraordinary dividends and a change in control feature that reduces the strike price based on a pre-established formula in the event of a change in control. Other terms are substantially similar to the 2001 Stock Incentive Plan. The Premium Option Plan expired on May 20, 2014 and at December 31, 2014 there are no options outstanding under the Premium Option Plan.
	2010 Cash Settled Restricted Stock Unit Plan
	In 2010, the Company instituted a restricted stock unit plan (the “2010 Cash Settled Restricted Stock Unit Plan”) allowing for the issuance of equity awards in the form of restricted stock units which will, subject to vesting requirements consistent with those utilized by the Company in respect of restricted shares, be settled in cash. Restricted stock units are liability awards with fair value measurement based on the market price of RenaissanceRe Common Shares at the end of each reporting period. Restricted share units are granted periodically by the Board of Directors and generally vest ratably over a four year period. During 2010, there were 900,000 restricted stock units reserved under the 2010 Cash Settled Restricted Stock Unit Plan.
	2010 Performance-Based Equity Incentive Plan
	In May 2010, RenaissanceRe’s shareholders approved the 2010 Performance-Based Equity Incentive Plan (“2010 Performance Plan”) under which 750,000 shares have been reserved (the “Performance Shares”). The Compensation Committee determined that, beginning in 2010 with the Company’s annual target-level incentive award grant cycle, 25% of the annual equity incentive award grants to each member of RenaissanceRe’s Executive Committee, which includes the Company’s Named Executive Officers, will be subject to vesting conditions based on both continued service and the attainment of pre-established performance goals. If performance goals are achieved, the Performance Shares will vest up to a maximum of 250% of target. The 2010 grants vest over a period of three years and are based on annual performance periods. All subsequent grants cliff vest at the end of a three year vesting period. The Performance Shares have a market condition which is the Company’s total shareholder return relative to its peer group. Total shareholder return is based on the average closing share price over the 20 trading days preceding and including the start and end of the performance period.
	The Chief Executive Officer (“CEO”) received a special performance award on his promotion to CEO effective July 1, 2013. The special equity award was issued in the form restricted stock and performance shares. The conditions attached to the restricted stock awards are identical to the conditions under the 2001 Stock Incentive Plan and the Non-Employee Director Stock Incentive Plan. If performance goals are achieved, the Performance Shares for the CEO vest up to a maximum of 250% of target. This grant vests over a period of four years, ending December 2016, and is based on annual performance periods.
	Valuation Assumptions
	Performance Shares
	The fair value of the Performance Shares is measured on the date of grant using a Monte Carlo simulation model which requires certain of the same inputs underlying the Black-Scholes methodology, that being: share price; expected volatility; expected term; expected dividend yield; and risk-free interest rates. The following are the weighted average-assumptions used to estimate the fair value for all Performance Shares issued in each respective year.
			Performance Shares
		Year ended December 31,	2014		2013
		Expected volatility (1)	14.5% - 18.6%		19.0% - 19.6%
		Expected term (in years)	n/a		n/a
		Expected dividend yield	n/a		n/a
		Risk-free interest rate (1)	0.08% - 1.65%		0.09% - 1.39%
	-1	The expected volatility and risk-free interest rate applied are specific to each tranche of Performance Shares.
	Expected volatility:  The expected volatility is estimated by the Company based on RenaissanceRe’s historical stock volatility.
	Expected term: The expected term is not applicable as the length of the performance periods are fixed and not subject to future employee behavior. Each tranche of the Performance Shares has a one year period during which performance is measured.
	Expected dividend yield:  The expected dividend yield is not applicable to Performance Shares as dividends are paid at the end of the vesting period and do not affect the value of the Performance Shares.
	Risk-free interest rate:  The risk free rate is estimated based on the yield on a U.S. treasury zero-coupon issued with a remaining term equal to the vesting period of the Performance Shares.
	The total cost of the Performance Shares is determined on the grant date based on the fair value calculated by the Monte Carlo simulation model. The Company recognizes cost equal to fair value per Performance Share multiplied by the target number of Performance Shares on the grant date. The cost is then recognized over the requisite service period net of estimated service-based forfeitures. When estimating forfeitures, the Company considers its historical forfeitures as well as expectations about employee behavior. For the year ended December 31, 2014, the Company used a 0% forfeiture rate for performance shares (2013 - 0%).
	Restricted Shares
	The fair value of restricted shares is determined based on the market value of the Company’s shares on the grant date. The estimated fair value of restricted shares, net of estimated forfeitures, is amortized as an expense over the requisite service period. When estimating forfeitures, the Company considers its historical forfeitures as well as expectations about employee behavior. For the year ended December 31, 2014, the Company used a 2% forfeiture rate for restricted shares (2013 - 2%).
	CSRSUs
	CSRSUs are revalued at the end of each quarterly reporting period based on the then value of RenaissanceRe’s stock price. The total cost is adjusted each quarter for unvested CSRSUs to reflect the current share price, and this total cost is amortized as an expense over the requisite service period, net of estimated forfeitures. When estimating forfeitures, the Company considers its historical forfeitures as well as expectations about employee behavior. For the year ended December 31, 2014, the Company used a 11% forfeiture rate for its CSRSUs (2013 - 13%).
	Summary of Stock Compensation Activity
	The following is a summary of activity under the Company’s existing stock compensation plans.
	2001 Stock Incentive and Non-Employee Director Stock Incentive Plans
			Weighted			Weighted			Weighted		Aggregate			Range of exercise prices
			options			average			average		intrinsic
			outstanding			exercise price			remaining		value
									contractual
									life
		Balance, December 31, 2011	1,973,307			$	47.33		4.6		$	53,363		$37.51 - $59.66
		Options granted	—			—								—
		Options forfeited	—			—
		Options expired	—			—
		Options exercised	(240,668	)		45.3					$	7,910
		Balance, December 31, 2012	1,732,639			$	47.61		3.7		$	58,305		$37.51 - $59.66
		Options granted	—			—								—
		Options forfeited	—			—
		Options expired	—			—
		Options exercised	(904,547	)		46.55					$	36,800
		Balance, December 31, 2013	828,092			$	48.77		2.9		$	40,221		$37.51 - $59.66
		Options granted	—			—								—
		Options forfeited	—			—
		Options expired	—			—
		Options exercised	(60,262	)		$	49.52				$	2,900
		Balance, December 31, 2014	767,830			$	48.71		2		$	37,246		$37.51 - $59.66
		Total options exercisable at December 31, 2014	767,830			$	48.71		2		$	37,246		$37.51 - $59.66
	Premium Option Plan
			Weighted			Weighted			Weighted		Aggregate			Range of exercise
			options			average			average		intrinsic  value			prices
			outstanding			exercise price			remaining
									contractual
									life
		Balance, December 31, 2011	1,192,000			$	73.94				$	—		$73.06 - $74.24
		Options granted	—			—
		Options forfeited	—			—
		Options expired	—			—
	Options exercised	(350,000	)		74.24					1,250
	Balance, December 31, 2012	842,000			$	73.82				$	6,265		$73.06 - $74.24
	Options granted	—			—
	Options forfeited	—			—
	Options expired	—			—
	Options exercised	(270,000	)		74.24					4,921
	Balance, December 31, 2013	572,000			$	73.62				$	13,567		$73.06 - $74.24
	Options granted	—			—
	Options forfeited	—			—
	Options expired	—			—
	Options exercised	(572,000	)		73.62					13,414
	Balance, December 31, 2014	—			$	—		0		$	—		$	—
	Total options exercisable at December 31, 2014	—			$	—		0		$	—		$	—
2010 Cash Settled Restricted Stock Unit Plan and 2010 Performance-Based Equity Incentive Plan
		Cash Settled			Performance Shares (1)
		Restricted
		Stock
		Unit Plan
		Number of			Number of		Weighted
		shares			shares		average
							grant-date fair value
	Nonvested at December 31, 2011	422,973			289,867		$	30.06
	Awards granted	225,105			144,635		$	28.17
	Awards vested	(128,401	)		(70,843	)
	Awards forfeited	(26,121	)		(4,139	)
	Nonvested at December 31, 2012	493,556			359,520		$	29.46
	Awards granted	149,760			134,358		$	33.46
	Awards vested	(176,265	)		(24,606	)
	Awards forfeited	(72,906	)		(109,729	)
	Nonvested at December 31, 2013	394,145			359,543		$	30.55
	Awards granted	119,382			102,668		$	46.45
	Awards vested	(159,094	)		—
	Awards forfeited	(16,110	)		(213,639	)
	Nonvested at December 31, 2014	338,323			248,572		$	39.62
(1) For Performance Shares, the number of shares is stated at the maximum number that can be attained if the performance conditions are fully met. Forfeitures represent shares forfeited due to vesting below the maximum attainable as a result of the Company not fully meeting the performance conditions.
Restricted Stock
		Employee						Non-employee director						Total
		restricted stock						restricted stock						restricted stock
		Number of			Weighted			Number of			Weighted			Number of		Weighted
		shares			average grant			shares			average grant			shares		average grant
					date fair						date fair					date fair
					value						value					value
	Nonvested at December 31, 2011	764,761			$	53.68		39,585			$	58.43		804,346		$	53.91
	Awards granted	226,827			72.46			16,874			71.69			243,701		72.4
	Awards vested	(337,683	)		51.06			(20,536	)		54.62			(358,219	)	51.26
	Awards forfeited	(7,157	)		53.9			—			—			(7,157	)	53.9
	Nonvested at December 31, 2012	646,748			$	61.63		35,923			$	66.83		682,671		$	61.9
	Awards granted	241,071			87.85			17,162			87.4			258,233		87.82
	Awards vested	(311,334	)		55.63			(21,599	)		66.06			(332,933	)	56.31
	Awards forfeited	(6,993	)		58.14			—			—			(6,993	)	58.14
	Nonvested at December 31, 2013	569,492			$	76.11		31,486			$	78.57		600,978		$	76.24
	Awards granted	215,054			95.79			14,455			95.06			229,509		95.74
	Awards vested	(332,725	)		73.74			(15,886	)		74.96			(348,611	)	73.79
	Awards forfeited	(99	)		55.8			—			—			(99	)	55.8
	Nonvested at December 31, 2014	451,722			$	87.29		30,055			$	88.41		481,777		$	87.36
Shares available for issuance under the Company’s 2001 Stock Incentive Plan, Non-Employee Director Stock Incentive Plan and 2010 Performance Share Plan totaled 3.0 million in the aggregate at December 31, 2014. The total fair value of shares and share units vested during the year ended December 31, 2014 was $48.7 million (2013 – $47.0 million, 2012 – $43.3 million). Cash in the amount of $0.5 million was received from employees as a result of employee stock option exercises during the year ended December 31, 2014 (2013 – $1.6 million, 2012 – $0.9 million). In connection with share vestings and option exercises, there was no excess windfall tax benefit realized by the Company due to its net operating loss position in the taxable jurisdictions in which it operates. RenaissanceRe issues new shares upon the exercise of an option.
The total stock compensation expense recognized in the Company’s consolidated statements of operations for the year ended December 31, 2014 was $37.6 million (2013 – $43.4 million, 2012 – $38.4 million). As of December 31, 2014, there was $30.7 million of total unrecognized compensation cost related to restricted stock awards, $21.6 million related to restricted stock units and $4.3 million related to performance shares expense, which will be recognized, on a weighted average, during the next 1.8, 1.6 and 1.9 years, respectively.
All of the Company’s employees are eligible for defined contribution pension plans. Contributions are primarily based upon a percentage of eligible compensation. The Company contributed $3.6 million to its defined contribution pension plans in 2014 (2013 – $3.5 million, 2012 – $3.4 million).

Statutory_Requirements

Statutory Requirements	12 Months Ended
	Dec. 31, 2014
Insurance [Abstract]
Statutory Requirements	STATUTORY REQUIREMENTS
	The Company’s insurance operations are subject to insurance laws and regulations in the jurisdictions in which they operate, the most significant of which currently include Bermuda and the U.K. These regulations include certain restrictions on the amount of dividends or other distributions, such as loans or cash advances, available to shareholders without prior approval of the respective regulatory authorities.
	The actual statutory capital and surplus, required statutory capital and surplus and restricted net assets of the Company’s regulated insurance operations in its most significant regulatory jurisdictions are detailed below:
			Bermuda					U.K. (1) (2)
		At December 31,	2014		2013			2014		2013
		Actual statutory capital and surplus	$	3,375,317	$	3,194,446		$	409,046	$	380,336
		Required statutory capital and surplus	479,346		562,126			409,046		380,336
		Restricted net assets	1,018,878		887,083			—		—
	-1	With respect to actual and required statutory capital and surplus, and as described below, underwriting capacity of a member of Lloyd’s must be supported by providing a deposit in the form of cash, securities or letters of credit, which are referred to as Funds at Lloyd’s (“FAL”). FAL is determined by Lloyd’s and is based on Syndicate 1458’s solvency and capital requirements as calculated through its internal model.
	-2	Syndicate 1458 is capitalized by its FAL, with the related assets not held on its balance sheet. As such, restricted net assets is not applicable to Syndicate 1458; however, the Company can make an application to obtain approval from Lloyd’s to have funds released to RenaissanceRe from Syndicate 1458, subject to passing a Lloyd’s release test.
	Statutory net income (loss) of the Company’s regulated insurance operations in its most significant regulatory jurisdictions are detailed below:
			Statutory Net Income (Loss)
			Bermuda		U.K.
		Year ended December 31, 2014	$	623,931	$	24,433
		Year ended December 31, 2013	712,820		7,745
		Year ended December 31, 2012	693,887		(10,967		)
	The difference between statutory financial statements and statements prepared in accordance with GAAP vary by jurisdiction; however, the primary difference is that for the Company’s regulated entities the statutory financial statements do not reflect deferred acquisition costs.
	The Company does not currently have any U.S. based insurance subsidiaries that would be subject to statutory accounting practices as defined by the National Association of Insurance Commissioners. In addition, none of the Company’s insurance subsidiaries used permitted practices that prevented the trigger of a regulatory event during the years ended December 31, 2014 and 2013.
	Bermuda-Based Insurance Entities
	Under the Insurance Act 1978, amendments thereto and related regulations of Bermuda (collectively, the “Insurance Act”), certain subsidiaries of RenaissanceRe are required to prepare statutory financial statements and to file in Bermuda a statutory financial return. The Insurance Act also requires these Bermuda insurance subsidiaries of RenaissanceRe to maintain certain measures of solvency and liquidity.
	Class 3B and Class 4 Insurers
	Under the Insurance Act, RenaissanceRe Specialty Risks and RenaissanceRe Specialty U.S. are defined as Class 3B insurers, and Renaissance Reinsurance and DaVinci are classified as Class 4 insurers, and therefore must maintain capital at a level equal to its enhanced capital requirement (“ECR”) which is established by reference to the Bermuda Solvency Capital Requirement (the “BSCR”) model. The BSCR is a mathematical model designed to give the Bermuda Monetary Authority (“BMA”) robust methods for determining an insurer’s capital adequacy. Underlying the BSCR is the belief that all insurers should operate on an ongoing basis with a view to maintaining their capital at a prudent level in excess of the minimum solvency margin otherwise prescribed under the Insurance Act. Alternatively, under the Insurance Act, insurers may, subject to the terms of the Insurance Act and to the BMA’s oversight, elect to utilize an approved internal capital model to determine regulatory capital. In either case, ECR shall at all times equal or exceed the respective Class 3B and Class 4 insurer’s minimum solvency margin and may be adjusted in circumstances where the BMA concludes that the insurer’s risk profile deviates significantly from the assumptions underlying its ECR or the insurer’s assessment of its risk management policies and practices used to calculate ECR applicable to it. While not specifically referred to in the Insurance Act, the BMA has also established a target capital level (“TCL”) for each Class 3B and Class 4 insurer equal to 120% of its respective ECR. While a Class 3B and Class 4 insurer is not currently required to maintain its statutory capital and surplus at this level, the TCL serves as an early warning tool for the BMA and failure to maintain statutory capital at least equal to the TCL will likely result in increased BMA regulatory oversight.
	Class 3B and Class 4 insurers are prohibited from declaring or paying any dividends if in breach of the required minimum solvency margin or minimum liquidity ratio (the “Relevant Margins”) or if the declaration or payment of such dividend would cause the insurer to fail to meet the Relevant Margins. Where an insurer fails to meet its Relevant Margins on the last day of any financial year, it is prohibited from declaring or paying any dividends during the next financial year without the prior approval of the BMA. Further, Class 3B and Class 4 insurers are prohibited from declaring or paying in any financial year dividends of more than 25% of its total statutory capital and surplus (as shown on its previous financial year’s statutory balance sheet) unless it files (at least seven days before payment of such dividends) with the BMA an affidavit stating that it will continue to meet its Relevant Margins. Class 3B and Class 4 insurers must obtain the BMA’s prior approval for a reduction by 15% or more of the total statutory capital as set forth in its previous year’s financial statements. These restrictions on declaring or paying dividends and distributions under the Insurance Act are in addition to the solvency requirements under the Bermuda Companies Act 1981 which apply to all Bermuda companies.
	The Company is currently completing its 2014 Bermuda-based statutory filings for Renaissance Reinsurance, DaVinci, RenaissanceRe Specialty Risks and RenaissanceRe Specialty U.S., which must be filed with the BMA on or before April 30, 2015, and at this time, the Company believes each of Renaissance Reinsurance, DaVinci, RenaissanceRe Specialty Risks and RenaissanceRe Specialty U.S. will exceed the target level of required statutory capital.
	For the years ended December 31, 2014 and 2013, Renaissance Reinsurance submitted applications to the BMA, and received approval, to exempt it from recording and recognizing certain third party guarantees as statutory liabilities and corresponding reductions of statutory capital and surplus for purposes of filing its statutory financial statements. The maximum monetary impact of including the third party guarantees in Renaissance Reinsurance’s statutory financial statements at December 31, 2014 would be an increase to statutory liabilities of $468.6 million (2013 - $168.0 million), and a corresponding decrease to statutory capital and surplus. If these amounts were to be included in Renaissance Reinsurance’s statutory financial statements, Renaissance Reinsurance would still exceed the required measures of solvency and liquidity, and the target level of required statutory capital, as discussed above.
	In addition, RenaissanceRe Specialty Risks is also eligible as an excess and surplus lines insurer in a number of states in the U.S. and under the various capital and surplus requirements in these states is required to maintain a minimum amount of capital and surplus. In this regard, the declaration of dividends from retained earnings and distributions from additional paid-in capital may be limited to the extent that the applicable above requirements are not met. The Company does not consider these requirements to be material.
	SPIs
	Under the Insurance Act, Upsilon RFO is considered an SPI. See “Note 11. Variable Interest Entities” for additional information related to Upsilon RFO. Unlike other (re)insurers, such as the Class 3B and Class 4 insurers discussed above, SPIs are fully funded to meet their (re)insurance obligations and are not exposed to insolvency, therefore the application and supervision processes are streamlined to facilitate the transparent structure.  Further, SPIs are currently not required to file annual loss reserve specialist opinions and the BMA has the discretion to modify such insurer’s reporting requirements under the Insurance Act.  Like other (re)insurers, the principal representative of an SPI has a duty to inform the BMA in relation to solvency matters, where applicable. In December 2013, the BMA issued a notice in which it proposed to amend the reporting requirements for SPIs. Under this notice, the BMA could require SPI’s to submit additional schedules together with the existing statutory financial return. These enhanced filing requirements have not yet been finalized by the BMA. The Company currently expects to receive directions from the BMA that would exempt Upsilon RFO from the proposed enhanced filing requirements.
	U.K.-Based Syndicate 1458
	RenaissanceRe CCL and Syndicate 1458 are subject to oversight by the Council of Lloyd’s. RSML is authorized by the U.K.’s Prudential Regulation Authority and regulated by the Financial Conduct Authority under the Financial Services and Markets Act 2000. Underwriting capacity of a member of Lloyd’s must be supported by providing a deposit in the form of cash, securities or letters of credit, which are referred to as FAL. This amount is determined by Lloyd’s and is based on Syndicate 1458’s solvency and capital requirement as calculated through its internal model. In addition, if the FAL are not sufficient to cover all losses, the Lloyd’s Central Fund provides an additional level of security for policyholders.
	Singapore-Based Entities
	Branches of Renaissance Reinsurance and DaVinci based in the Republic of Singapore (the “Singapore Branches”) have each received a license to carry on insurance business as a general reinsurer.  The activities of the Singapore Branches are primarily regulated by the Monetary Authority of Singapore pursuant to Singapore’s Insurance Act. Additionally, the Singapore Branches are regulated by the Accounting and Corporate Regulatory Authority as a foreign company pursuant to Singapore’s Companies Act.  Prior to the establishment of the Singapore Branches, Renaissance Reinsurance and DaVinci had maintained representative offices in Singapore since April 2012. The activities and regulatory requirements of the Singapore Branches are not considered to be material to the Company.
	Dividend Restrictions of RenaissanceRe
	As a Bermuda-domiciled holding company, RenaissanceRe has limited operations of its own and its assets consist primarily of investments in subsidiaries, and to a degree, cash and securities. Accordingly, RenaissanceRe’s future cash flows largely depend on the availability of dividends or other statutorily permissible payments from subsidiaries. The ability to pay such dividends is limited by the applicable laws and regulations of the various countries and states in which these subsidiaries operate, including, among others, Bermuda, the U.S., the U.K. and Ireland. RenaissanceRe’s ability to pay dividends and distribute capital to shareholders is limited by the Bermuda Companies Act 1981, insofar as after the payment, RenaissanceRe must still be able to pay its liabilities as they come due and the realizable value of its assets must be greater than its liabilities. At December 31, 2014, $2.4 billion of RenaissanceRe’s retained earnings would be unrestricted and available for payment of dividends or distribution to shareholders of RenaissanceRe (2013 - $2.6 billion).
	Multi-Beneficiary Reinsurance Trusts
	Effective March 15, 2011, each of Renaissance Reinsurance and DaVinci was approved as a Trusteed Reinsurer in the state of New York and established a multi-beneficiary reinsurance trust (“MBRT”) to collateralize its (re)insurance liabilities associated with U.S. domiciled cedants. The MBRTs are subject to the rules and regulations of the state of New York and the respective deed of trust, including but not limited to certain minimum capital funding requirements, investment guidelines, capital distribution restrictions and regulatory reporting requirements. Assets held under trust at December 31, 2014 with respect to the MBRTs totaled $508.6 million and $173.7 million for Renaissance Reinsurance and DaVinci, respectively (2013 – $505.1 million and $173.9 million, respectively), compared to the minimum amount required under U.S. state regulations of $409.9 million and $105.7 million, respectively (2013 – $441.7 million and $135.2 million, respectively).
	Multi-Beneficiary Reduced Collateral Reinsurance Trusts
	Effective December 31, 2012, each of Renaissance Reinsurance and DaVinci has been approved as an “eligible reinsurer” in the state of Florida.  Therefore they are each authorized to provide reduced collateral equal to 20% of their net outstanding insurance liabilities to Florida-domiciled insurers.  Each of Renaissance Reinsurance and DaVinci has established a multi-beneficiary reduced collateral reinsurance trust (“RCT”) to collateralize its (re)insurance liabilities associated with Florida-domiciled cedants.  Because the RTCs were established in New York, they are subject to the rules and regulations of the state of New York including but not limited to certain minimum capital funding requirements, investment guidelines, capital distribution restrictions and regulatory reporting requirements. Assets held under trust at December 31, 2014 with respect to the RCTs totaled $43.2 million and $18.8 million for Renaissance Reinsurance and DaVinci, respectively (2013 - $21.1 million and $18.6 million, respectively), compared to the minimum amount required under U.S. state regulations of $17.5 million and $10.3 million, respectively (2013 - $16.3 million and $10.2 million, respectively).

Derivative_Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2014
Summary of Derivative Instruments [Abstract]
Derivative Instruments	DERIVATIVE INSTRUMENTS
	The Company enters into derivative instruments such as futures, options, swaps, forward contracts and other derivative contracts primarily to manage its foreign currency exposure, obtain exposure to a particular financial market, for yield enhancement, or for trading and speculation. The Company accounts for its derivatives in accordance with FASB ASC Topic Derivatives and Hedging, which requires all derivatives to be recorded at fair value on the Company’s balance sheet as either assets or liabilities, depending on the rights or obligations of the derivatives, with changes in fair value reflected in current earnings. The Company does not currently apply hedge accounting in respect of any positions reflected in its consolidated financial statements. The Company’s derivative instruments are generally traded under International Swaps and Derivatives Association master agreements, which establish the terms of the transactions entered into with the Company’s derivative counterparties. In the event one party becomes insolvent or otherwise defaults on its obligations, a master agreement generally permits the non-defaulting party to accelerate and terminate all outstanding transactions and net the transactions’ marked-to-market values so that a single sum in a single currency will be owed by, or owed to, the non-defaulting party. Effectively, this contractual close-out netting reduces credit exposure from gross to net exposure. Where the Company has entered into master netting agreements with counterparties, or the Company has the legal and contractual right to offset positions, the derivative positions are generally netted by counterparty and are reported accordingly in other assets and other liabilities.
	The tables below show the gross and net amounts of recognized derivative assets and liabilities, including the location on the consolidated balance sheets and fair value of the Company’s principal derivative instruments:
			Derivative Assets
		At December 31, 2014	Gross Amounts of Recognized Assets				Gross Amounts Offset in the Balance Sheet				Net Amounts of Assets Presented in the Balance Sheet				Balance Sheet Location	Collateral		Net Amount
		Interest rate futures	$	468			468				$	—			Other assets	$	—	$	—
		Foreign currency forward contracts (1)	5,740				1,737				4,003				Other assets	—		4,003
		Foreign currency forward contracts (2)	3,959				648				3,311				Other assets	—		3,311
		Credit default swaps	468				88				380				Other assets	310		70
		Total	$	10,635			$	2,941			$	7,694				$	310	$	7,384
			Derivative Liabilities
		At December 31, 2014	Gross Amounts of Recognized Liabilities				Gross Amounts Offset in the Balance Sheet				Net Amounts of Liabilities Presented in the Balance Sheet				Balance Sheet Location	Collateral Pledged		Net Amount
		Interest rate futures	$	1,037			468				$	569			Other liabilities	$	569	$	—
		Foreign currency forward contracts (1)	1,319				967				352				Other liabilities	—		352
		Foreign currency forward contracts (2)	724				649				75				Other liabilities	—		75
		Credit default swaps	251				88				163				Other liabilities	—		163
		Weather contract	190				—				190				Other liabilities	190		—
		Total	$	3,521			$	2,172			$	1,349				$	759	$	590
	-1	Contracts used to manage foreign currency risks in underwriting and non-investment operations.
	-2	Contracts used to manage foreign currency risks in investment operations.
			Derivative Assets
		At December 31, 2013	Gross Amounts of Recognized Assets				Gross Amounts Offset in the Balance Sheet				Net Amounts of Assets Presented in the Balance Sheet				Balance Sheet Location	Collateral		Net Amount
		Interest rate futures	$	897			62				$	835			Other assets	$	—	$	835
		Foreign currency forward contracts (1)	9,612				1,179				8,433				Other assets	—		8,433
		Foreign currency forward contracts (2)	1,013				338				675				Other assets	—		675
		Credit default swaps	806				82				724				Other assets	310		414
		Total	$	12,328			$	1,661			$	10,667				$	310	$	10,357
			Derivative Liabilities
		At December 31, 2013	Gross Amounts of Recognized Liabilities				Gross Amounts Offset in the Balance Sheet				Net Amounts of Liabilities Presented in the Balance Sheet				Balance Sheet Location	Collateral Pledged		Net Amount
		Interest rate futures	$	74			62				$	12			Other liabilities	$	12	$	—
		Foreign currency forward contracts (1)	2,204				28				2,176				Other liabilities	—		2,176
		Foreign currency forward contracts (2)	1,557				338				1,219				Other liabilities	—		1,219
		Credit default swaps	94				82				12				Other liabilities	—		12
		Weather contract	2,490				—				2,490				Other liabilities	2,490		—
		Total	$	6,419			$	510			$	5,909				$	2,502	$	3,407
	-1	Contracts used to manage foreign currency risks in underwriting and non-investment operations.
	-2	Contracts used to manage foreign currency risks in investment operations.
	Refer to “Note 5. Investments” for information on reverse repurchase agreements.
	The location and amount of the gain (loss) recognized in the Company’s consolidated statements of operations related to its principal derivative instruments are shown in the following table:
			Location of gain (loss)		Amount of gain (loss) recognized on
			recognized on derivatives		derivatives
		Year ended December 31,			2014				2013				2012
		Interest rate futures	Net realized and unrealized gains on investments		$	(32,713	)		$	29,695			$	(1,746	)
		Foreign currency forward contracts (1)	Net foreign exchange gains		4,457				889				13,804
		Foreign currency forward contracts (2)	Net foreign exchange gains		12,623				(3,015		)		(3,445		)
		Credit default swaps	Net realized and unrealized gains on investments		328				1,363				1,074
		Weather contract	Net realized and unrealized gains on investments		1,454				(1,331		)		—
		Total			$	(13,851	)		$	27,601			$	9,687
	-1	Contracts used to manage foreign currency risks in underwriting and non-investment operations.
	-2	Contracts used to manage foreign currency risks in investment operations.
	The Company is not aware of the existence of any credit-risk related contingent features that it believes would be triggered in its derivative instruments that are in a net liability position at December 31, 2014.
	Interest Rate Futures
	The Company uses interest rate futures within its portfolio of fixed maturity investments to manage its exposure to interest rate risk, which can include increasing or decreasing its exposure to this risk. At December 31, 2014, the Company had $587.0 million of notional long positions and $617.4 million of notional short positions of primarily Eurodollar, U.S. treasury and non-U.S. dollar futures contracts (2013 – $1,169.3 million and $356.6 million, respectively). The fair value of these derivatives is determined using exchange traded prices.
	Foreign Currency Derivatives
	The Company’s functional currency is the U.S. dollar. The Company writes a portion of its business in currencies other than U.S. dollars and may, from time to time, experience foreign exchange gains and losses in the Company’s consolidated financial statements. All changes in exchange rates, with the exception of non-monetary assets and liabilities, are recognized currently in the Company’s consolidated statements of operations.
	Underwriting Operations Related Foreign Currency Contracts
	The Company’s foreign currency policy with regard to its underwriting operations is generally to hold foreign currency assets, including cash, investments and receivables that approximate the foreign currency liabilities, including claims and claim expense reserves and reinsurance balances payable. When necessary, the Company may use foreign currency forward and option contracts to minimize the effect of fluctuating foreign currencies on the value of non-U.S. dollar denominated assets and liabilities associated with its underwriting operations. The fair value of the Company’s underwriting operations related foreign currency contracts is determined using indicative pricing obtained from counterparties or broker quotes. At December 31, 2014, the Company had outstanding underwriting related foreign currency contracts of $144.8 million in notional long positions and $121.6 million in notional short positions, denominated in U.S. dollars (2013 – $263.6 million and $139.8 million, respectively).
	Investment Portfolio Related Foreign Currency Forward Contracts
	The Company’s investment operations are exposed to currency fluctuations through its investments in non-U.S. dollar fixed maturity investments, short term investments and other investments. To economically hedge its exposure to currency fluctuations from these investments, the Company has entered into foreign currency forward contracts. The fair value of the Company’s investment portfolio related foreign currency forward contracts is determined using an interpolated rate based on closing forward market rates. At December 31, 2014, the Company had outstanding investment portfolio related foreign currency contracts of $35.8 million in notional long positions and $150.1 million in notional short positions, denominated in U.S. dollars (2013 – $39.6 million and $159.1 million, respectively).
	Credit Derivatives
	The Company’s exposure to credit risk is primarily due to its fixed maturity investments, short term investments, premiums receivable and reinsurance recoverable.  From time to time, the Company purchases credit derivatives to hedge its exposures in the insurance industry, and to assist in managing the credit risk associated with ceded reinsurance.  The Company also employs credit derivatives in its investment portfolio to either assume credit risk or hedge its credit exposure. The fair value of the credit derivatives is determined using industry valuation models, broker bid indications or internal pricing valuation techniques.  The fair value of these credit derivatives can change based on a variety of factors including changes in credit spreads, default rates and recovery rates, the correlation of credit risk between the referenced credit and the counterparty, and market rate inputs such as interest rates. At December 31, 2014, the Company had outstanding credit derivatives of $4.6 million in notional long positions and $19.4 million in notional short positions, denominated in U.S. dollars (2013 – $7.1 million and $18.4 million, respectively).
	Weather Contract
	The Company, from time to time, transacts in certain derivative-based risk management products that address weather-related risks. The fair value of these contracts is determined through the use of an internal valuation model with the inputs to the internal valuation model based on proprietary data as observable market inputs are not available.  The most significant unobservable input is the potential payment that would become due to a counterparty following the occurrence of a triggering event as reported by an external agency.  Generally, the Company’s portfolio of such derivatives is relatively small and such derivatives are frequently seasonal in nature. At December 31, 2014, the Company had an outstanding weather contract with an insurance company of $2.2 million in a notional short position (2013 - $6.4 million).

Commitments_Contingencies_and_

Commitments, Contingencies and Other Items	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Other Items	COMMITMENTS, CONTINGENCIES AND OTHER ITEMS
	CONCENTRATION OF CREDIT RISK
	Instruments which potentially subject the Company to concentration of credit risk consist principally of investments, including the Company’s equity method investments, cash, premiums receivable and reinsurance balances. The Company limits the amount of credit exposure to any one financial institution and, except for U.S. Government securities, none of the Company’s investments exceeded 10% of shareholders’ equity at December 31, 2014. See “Note 7. Reinsurance”, for information with respect to reinsurance recoverable.
	EMPLOYMENT AGREEMENTS
	The Board of Directors has authorized the execution of employment agreements between the Company and certain officers. These agreements provide for, among other things, severance payments under certain circumstances, as well as accelerated vesting of options and restricted stock grants, upon a change in control, as defined therein and under the terms of the Company’s 2001 Stock Incentive Plan, Premium Option Plan and 2010 Performance-Based Equity Incentive Plan.
	LETTERS OF CREDIT AND OTHER COMMITMENTS
	At December 31, 2014, the Company’s banks have issued letters of credit of approximately $624.9 million in favor of certain ceding companies, including the letter of credit facility with CEP noted below. In connection with the Company’s Top Layer Re joint venture, Renaissance Reinsurance has committed $37.5 million of collateral to support a letter of credit and is obligated to make a mandatory capital contribution of up to $50.0 million in the event that a loss reduces Top Layer Re’s capital and surplus below a specified level. The letters of credit are secured by cash and investments of similar amounts. The Company’s standby letter of credit facility contains certain financial covenants.
	On April 26, 2010, Renaissance Reinsurance and CEP entered into a Pledge Agreement in respect of its letter of credit facility with CEP which is evidenced by the Master Reimbursement Agreement, dated as of April 29, 2009, and provides for the issuance and renewal of letters of credit which are used to support business written by Syndicate 1458. Letter of credit fees will be payable pursuant to the terms of the Reimbursement Agreement. At December 31, 2014, these letters of credit amounted to $300.0 million and £70.0 million, respectively. Pursuant to the Pledge Agreement, Renaissance Reinsurance has agreed to pledge and maintain certain securities with a collateral value equal to 75% of the aggregate amount of the then outstanding letters of credit. In respect of the 25% unsecured portion, Renaissance Reinsurance is required to comply with certain financial covenants, including maintaining a certain minimum financial strength rating, minimum net worth, and a maximum consolidated debt to capital ratio for the consolidated group. In the event Renaissance Reinsurance is unable to satisfy any of these financial covenants, it will be required to pledge additional collateral in respect of the unsecured portion.
	PRIVATE EQUITY AND INVESTMENT COMMITMENTS
	The Company has committed capital to private equity partnerships and other entities of $623.8 million, of which $544.1 million has been contributed at December 31, 2014. The Company’s remaining commitments to these funds at December 31, 2014 totaled $84.0 million. These commitments do not have a defined contractual commitment date.
	INDEMNIFICATIONS AND WARRANTIES
	In the ordinary course of its business, the Company may enter into contracts or agreements that contain indemnifications or warranties. Future events could occur that lead to the execution of these provisions against the Company. Based on past experience, management currently believes that the likelihood of such an event is remote.
	OPERATING AND CAPITAL LEASES
	The Company leases office space under operating leases which expire at various dates through 2021. Future minimum lease payments under existing operating leases are expected to be as follows:
			Minimum
			lease payments
		2015	$	6,184
		2016	5,234
		2017	2,321
		2018	2,035
		2019	1,455
		After 2019	142
		Future minimum lease payments under existing operating leases	$	17,371
	The Company’s capital leases primarily relate to office space in Bermuda with an initial lease term of 20 years, ending in 2028, and a bargain renewal option for an additional 30 years. The future minimum lease payments of the Company’s capital leases are detailed below, and relate principally to the transaction noted above, excluding the bargain renewal option.
			Minimum
			lease payments
		2015	$	3,017
		2016	3,017
		2017	2,417
		2018	2,501
		2019	2,661
		After 2019	23,433
		Future minimum lease payments under existing capital leases	$	37,046
	LITIGATION
	The Company and its subsidiaries are subject to lawsuits and regulatory actions in the normal course of business that do not arise from or directly relate to claims on reinsurance treaties or contracts or direct surplus lines insurance policies.  This category of business litigation may involve allegations of underwriting or claims-handling errors or misconduct, employment claims, regulatory actions or disputes arising from the Company’s business ventures.  The Company’s operating subsidiaries are subject to claims litigation involving, among other things, disputed interpretations of policy coverages.  Generally, the Company’s direct surplus lines insurance operations are subject to greater frequency and diversity of claims and claims-related litigation than its reinsurance operations and, in some jurisdictions, may be subject to direct actions by allegedly injured persons or entities seeking damages from policyholders.  These lawsuits, involving claims on policies issued by the Company’s subsidiaries which are typical to the insurance industry in general and in the normal course of business, are considered in its loss and loss expense reserves which are discussed in its loss reserves discussion.  In addition, the Company may from time to time engage in litigation or arbitration related to its claims for payment in respect of ceded reinsurance, including disputes that challenge the Company’s ability to enforce its underwriting intent. Such matters could result, directly or indirectly, in providers of protection not meeting their obligations to the Company or not doing so on a timely basis. The Company may also be subject to other disputes from time to time, relating to operational or other matters distinct from insurance or reinsurance claims. Any litigation or arbitration, or regulatory process, contains an element of uncertainty, and the value of an exposure or a gain contingency related to a dispute is difficult to estimate accordingly. Currently, the Company believes that no individual litigation or arbitration to which it is presently a party is likely to have a material adverse effect on its financial condition, business or operations.
	PLATINUM ACQUISITION
	On November 24, 2014, the Company announced that RenaissanceRe and Platinum entered into a Merger Agreement under which RenaissanceRe will acquire Platinum. The transaction will benefit the combined companies’ clients through an expanded product offering and broker relationships and will accelerate the growth of the Company’s U.S. specialty and casualty reinsurance platform. The agreement has been unanimously approved by both companies’ Board of Directors and, if approved by Platinum shareholders, the transaction is expected to close on March 2, 2015. Platinum has scheduled a special meeting of shareholders to consider and vote upon the proposed acquisition and related matters on February 27, 2015. There can be no assurance that the Merger will occur.
	Upon completion of the Merger, Platinum Common Shares (other than dissenting shares) shall be canceled and converted into the right to receive, at the election of the holder thereof in accordance with the terms of the Merger Agreement, (i) the cash election consideration, which is an amount of cash equal to $66.00 (the “Cash Election Consideration”), (ii) the share election consideration, which is 0.6504 common shares, par value $1.00 per share of RenaissanceRe (“RenaissanceRe Common Shares”) (the “Share Election Consideration”), or (iii) the standard election consideration (the “Standard Election Consideration”), which is comprised of the standard exchange ratio (which is 0.2960 RenaissanceRe Common Shares) and the standard cash amount (which is an amount of cash equal to $35.96), in each case less applicable withholding taxes and plus cash in lieu of any fractional RenaissanceRe Common Shares such Platinum shareholders would otherwise be entitled to receive. The number of RenaissanceRe Common Shares to be issued to Platinum shareholders as consideration for the Merger is 7.5 million, and each of the Cash Election Consideration and the Share Election Consideration is subject to proration if the un-prorated aggregate share consideration is less than or greater than, respectively, 7.5 million RenaissanceRe Common Shares. All Platinum Common Shares that are held by Platinum as treasury stock or held by any wholly owned subsidiary of Platinum, or owned by RenaissanceRe or any wholly owned subsidiary of RenaissanceRe immediately before the Merger, will be canceled and no payment will be made in respect thereof.
	In addition, the Merger Agreement requires that, subject to applicable laws, following the date of approval and adoption of the Merger Agreement by the Platinum shareholders and prior to the Effective Time (as defined in the Merger Agreement), Platinum shall declare and pay the special dividend of $10.00 per Platinum Common Share (the “Special Dividend”) to the holders of record of outstanding Platinum Common Shares as of a record date for the Special Dividend to be set as designated by Platinum’s board of directors. On February 10, 2015, Platinum announced that the Special Dividend would be payable prior to the effective time of the Merger on the closing date of the Merger to Platinum shareholders of record at the close of business on the last business day prior to the closing date, which Special Dividend is conditioned on the Merger having been approved by the shareholders of Platinum at the special meeting of its shareholders on February 27, 2015 (or any adjournment or postponement thereof).
	The aggregate consideration for the transaction is expected to be approximately $1.9 billion, comprised of the Special Dividend, the issuance of 7.5 million RenaissanceRe Common Shares, and cash consideration. The Company anticipates funding the cash consideration to be paid by RenaissanceRe from available cash resources, the liquidation of certain of the Company’s fixed maturity investments trading, and short term alternative financing. Following the closing of the Merger, if such closing occurs, the Company intends to issue $300.0 million in debt to replace the short term alternative financing used to fund part of the cash consideration to be paid by RenaissanceRe. However, there can be no assurance that the Company will be able to secure adequate sources of financing on favorable terms.
	The Company incurred $6.7 million of corporate expenses associated with the Merger in 2014 and is contractual obligated to pay an investment bank $10.0 million upon closing of the Merger. The Company expects to incur additional costs and expenses associated with the Merger in 2015.

Quarterly_Financial_Informatio

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Data [Abstract]
Quarterly Financial Information (Unaudited)	QUARTERLY FINANCIAL INFORMATION (UNAUDITED)
			Quarter Ended						Quarter Ended						Quarter Ended						Quarter Ended
			March 31,						June 30,						September 30,						December 31,
			2014			2013			2014			2013			2014			2013			2014			2013
		Revenues
		Gross premiums written	$	705,260		$	635,418		$	511,540		$	703,223		$	200,992		$	182,649		$	132,780		$	84,122
		Net premiums written	$	450,347		$	436,813		$	346,407		$	559,109		$	159,713		$	127,241		$	111,769		$	80,784
		(Increase) decrease in unearned premiums	(163,813		)	(165,558		)	(85,991		)	(267,220		)	99,266			167,476			144,718			175,981
		Net premiums earned	286,534			271,255			260,416			291,889			258,979			294,717			256,487			256,765
		Net investment income	38,948			43,202			34,541			26,163			24,941			59,931			25,886			78,732
		Net foreign exchange (losses) gains	(1,061		)	614			2,392			(932		)	5,036			488			(107		)	1,747
		Equity in earnings of other ventures	4,199			5,835			7,232			3,772			9,806			7,313			4,838			6,274
		Other income (loss)	62			(1,709		)	(535		)	(1,128		)	(1,169		)	651			1,219			(173		)
		Net realized and unrealized gains (losses) on investments	14,927			14,269			27,128			(69,529		)	(31,097		)	28,472			30,475			61,864
		Total revenues	343,609			333,466			331,174			250,235			266,496			391,572			318,798			405,209
		Expenses
		Net claims and claim expenses incurred	58,915			27,251			81,388			103,962			69,647			60,928			(12,003		)	(20,854		)
		Acquisition costs	33,700			25,009			33,477			31,767			37,550			37,699			39,749			31,026
		Operational expenses	42,624			45,986			45,841			42,789			46,972			44,672			55,202			57,658
		Corporate expenses	4,545			4,482			3,954			21,529			3,905			4,307			10,583			3,304
		Interest expense	4,293			5,034			4,292			4,300			4,290			4,298			4,289			4,297
		Total expenses	144,077			107,762			168,952			204,347			162,364			151,904			97,820			75,431
		Income from continuing operations before taxes	199,532			225,704			162,222			45,888			104,132			239,668			220,978			329,778
		Income tax (expense) benefit	(166		)	(122		)	204			(11		)	(245		)	(223		)	(401		)	(1,336		)
		Income from continuing operations	199,366			225,582			162,426			45,877			103,887			239,445			220,577			328,442
		Income (loss) from discontinued operations	—			9,774			—			2,427			—			(9,779		)	—			—
		Net income	199,366			235,356			162,426			48,304			103,887			229,666			220,577			328,442
		Net income attributable to noncontrolling interests	(42,768		)	(38,607		)	(36,078		)	(14,015		)	(30,477		)	(44,331		)	(44,215		)	(54,191		)
		Net income available to RenaissanceRe	156,598			196,749			126,348			34,289			73,410			185,335			176,362			274,251
		Dividends on preference shares	(5,595		)	(6,275		)	(5,596		)	(7,483		)	(5,595		)	(5,595		)	(5,595		)	(5,595		)
		Net income available to RenaissanceRe common shareholders	$	151,003		$	190,474		$	120,752		$	26,806		$	67,815		$	179,740		$	170,767		$	268,656
		Income from continuing operations available to RenaissanceRe common shareholders per common share – basic	$	3.61		$	4.1		$	3		$	0.55		$	1.72		$	4.32		$	4.46		$	6.14
		Income (loss) from discontinued operations available (attributable) to RenaissanceRe common shareholders per common share – basic	—			0.22			—			0.06			—			(0.23		)	—			—
		Net income available to RenaissanceRe common shareholders per common share – basic	$	3.61		$	4.32		$	3		$	0.61		$	1.72		$	4.09		$	4.46		$	6.14
		Income from continuing operations available to RenaissanceRe common shareholders per common share – diluted	$	3.56		$	4.01		$	2.95		$	0.55		$	1.7		$	4.23		$	4.42		$	6.05
		Income (loss) from discontinued operations available (attributable) to RenaissanceRe common shareholders per common share – diluted	—			0.22			—			0.05			—			(0.22		)	—			—
		Net income available to RenaissanceRe common shareholders per common share – diluted	$	3.56		$	4.23		$	2.95		$	0.6		$	1.7		$	4.01		$	4.42		$	6.05
		Average shares outstanding – basic	41,238			43,461			39,736			43,372			38,975			43,330			37,752			43,160
		Average shares outstanding – diluted	41,903			44,290			40,395			44,243			39,433			44,135			38,145			43,769

Condensed_Consolidating_Financ

Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries	12 Months Ended
	Dec. 31, 2014
Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries [Abstract]
Condensed Financial Statements	CONDENSED CONSOLIDATING FINANCIAL INFORMATION PROVIDED IN CONNECTION WITH OUTSTANDING DEBT OF SUBSIDIARIES
	The following tables present condensed consolidating balance sheets at December 31, 2014 and 2013, condensed consolidating statements of operations, condensed consolidating statements of comprehensive income and condensed consolidating statements of cash flows for the years ended December 31, 2014, 2013 and 2012, respectively, for RenaissanceRe, RRNAH and RenaissanceRe’s other subsidiaries. RRNAH is a 100% owned subsidiary of RenaissanceRe.
	On March 17, 2010, RRNAH issued, and RenaissanceRe guaranteed, $250.0 million of 5.75% Senior Notes due March 15, 2020, with interest on the notes payable on March 15 and September 15 of each year. The notes can be redeemed by RRNAH prior to maturity, subject to payment of a “make-whole” premium. The notes, which are senior obligations, contain various covenants, including limitations on mergers and consolidations, restrictions as to the disposition of the stock of designated subsidiaries and limitations on liens of the stock of designated subsidiaries.
	Condensed Consolidating Balance Sheet at December 31, 2014	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
		Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
		(Parent			Holdings Inc.			Holdings Ltd.			-2
		Guarantor)			(Subsidiary			Subsidiaries and
					Issuer)			Eliminations
								(Non-guarantor
								Subsidiaries)
								-1
	Assets
	Total investments	$	137,006		$	88,150		$	6,518,594		$	—		$	6,743,750
	Cash and cash equivalents	5,986			1,033			518,565			—			525,584
	Investments in subsidiaries	3,509,974			71,796			—			(3,581,770		)	—
	Due from subsidiaries and affiliates	126,548			23			—			(126,571		)	—
	Premiums receivable	—			—			440,007			—			440,007
	Prepaid reinsurance premiums	—			—			94,810			—			94,810
	Reinsurance recoverable	—			—			66,694			—			66,694
	Accrued investment income	—			121			26,388			—			26,509
	Deferred acquisition costs	—			—			110,059			—			110,059
	Receivable for investments sold	10			—			52,380			—			52,390
	Other assets	112,400			1,242			131,563			(101,458		)	143,747
	Total assets	$	3,891,924		$	162,365		$	7,959,060		$	(3,809,799	)	$	8,203,550
	Liabilities, Noncontrolling Interests and Shareholders’ Equity
	Liabilities
	Reserve for claims and claim expenses	$	—		$	—		$	1,412,510		$	—		$	1,412,510
	Unearned premiums	—			—			512,386			—			512,386
	Debt	—			249,522			—			—			249,522
	Amounts due to subsidiaries and affiliates	6,000			233			—			(6,233		)	—
	Reinsurance balances payable	—			—			454,580			—			454,580
	Payable for investments purchased	—			—			203,021			—			203,021
	Other liabilities	20,209			4,013			351,344			(1,458		)	374,108
	Total liabilities	26,209			253,768			2,933,841			(7,691		)	3,206,127
	Redeemable noncontrolling interests	—			—			1,131,708			—			1,131,708
	Shareholders’ Equity
	Total shareholders’ equity	3,865,715			(91,403		)	3,893,511			(3,802,108		)	3,865,715
	Total liabilities, noncontrolling interests and shareholders’ equity	$	3,891,924		$	162,365		$	7,959,060		$	(3,809,799	)	$	8,203,550
	-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
	-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
	Condensed Consolidating Balance Sheet at December 31, 2013	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
		Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
		(Parent			Holdings Inc.			Holdings Ltd.			-2
		Guarantor)			(Subsidiary			Subsidiaries and
					Issuer)			Eliminations
								(Non-guarantor
								Subsidiaries)
								-1
	Assets
	Total investments	$	210,719		$	98,784		$	6,512,209		$	—		$	6,821,712
	Cash and cash equivalents	8,796			4,027			395,209			—			408,032
	Investments in subsidiaries	3,294,729			74,718			—			(3,369,447		)	—
	Due from subsidiaries and affiliates	296,752			—			—			(296,752		)	—
	Premiums receivable	—			—			474,087			—			474,087
	Prepaid reinsurance premiums	—			—			66,132			—			66,132
	Reinsurance recoverable	—			—			101,025			—			101,025
	Accrued investment income	—			110			33,955			—			34,065
	Deferred acquisition costs	—			—			81,684			—			81,684
	Receivable for investments sold	14			—			75,831			—			75,845
	Other assets	112,234			1,481			102,834			(100,000		)	116,549
	Total assets	$	3,923,244		$	179,120		$	7,842,966		$	(3,766,199	)	$	8,179,131
	Liabilities, Redeemable Noncontrolling Interest and Shareholders’ Equity
	Liabilities
	Reserve for claims and claim expenses	$	—		$	—		$	1,563,730		$	—		$	1,563,730
Unearned premiums	—			—			477,888			—			477,888
Debt	—			249,430			—			—			249,430
Amounts due to subsidiaries and affiliates	—			3,173			—			(3,173		)	—
Reinsurance balances payable	—			—			293,022			—			293,022
Payable for investments purchased	—			—			193,221			—			193,221
Other liabilities	18,860			6,953			371,783			—			397,596
Total liabilities	18,860			259,556			2,899,644			(3,173		)	3,174,887
Redeemable noncontrolling interest	—			—			1,099,860			—			1,099,860
Shareholders’ Equity
Total shareholders’ equity	3,904,384			(80,436		)	3,843,462			(3,763,026		)	3,904,384
Total liabilities, redeemable noncontrolling interest and shareholders’ equity	$	3,923,244		$	179,120		$	7,842,966		$	(3,766,199	)	$	8,179,131
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement of Operations for	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
the year ended December 31, 2014	Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
	(Parent			Holdings Inc.			Holdings Ltd.			-2
	Guarantor)			(Subsidiary			Subsidiaries and
				Issuer)			Eliminations
							(Non-guarantor
							Subsidiaries)
							-1
Revenues
Net premiums earned	$	—		$	—		$	1,062,416		$	—		$	1,062,416
Net investment income	2,706			1,765			123,582			(3,737		)	124,316
Net foreign exchange (losses) gains	(13		)	—			6,273			—			6,260
Equity in earnings of other ventures	—			—			26,075			—			26,075
Other loss	—			(7		)	(416		)	—			(423		)
Net realized and unrealized gains on investments	83			9,069			32,281			—			41,433
Total revenues	2,776			10,827			1,250,211			(3,737		)	1,260,077
Expenses
Net claims and claim expenses incurred	—			—			197,947			—			197,947
Acquisition expenses	—			—			144,476			—			144,476
Operational expenses	(4,890		)	7,004			188,857			(332		)	190,639
Corporate expenses	20,787			238			1,962			—			22,987
Interest expense	—			14,467			2,697			—			17,164
Total expenses	15,897			21,709			535,939			(332		)	573,213
(Loss) income before equity in net income of subsidiaries and taxes	(13,121		)	(10,882		)	714,272			(3,405		)	686,864
Equity in net income (loss) of subsidiaries	545,839			(4,343		)	—			(541,496		)	—
Income (loss) before taxes and noncontrolling interest	532,718			(15,225		)	714,272			(544,901		)	686,864
Income tax benefit (expense)	—			4,064			(4,672		)	—			(608		)
Net income (loss)	532,718			(11,161		)	709,600			(544,901		)	686,256
Net income attributable to noncontrolling interests	—			—			(153,538		)	—			(153,538		)
Net income (loss) attributable to RenaissanceRe	532,718			(11,161		)	556,062			(544,901		)	532,718
Dividends on preference shares	(22,381		)	—			—			—			(22,381		)
Net income (loss) attributable to RenaissanceRe common shareholders	$	510,337		$	(11,161	)	$	556,062		$	(544,901	)	$	510,337
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement of Comprehensive Income (Loss) for the year ended December 31, 2014	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
	Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
	(Parent			Holdings Inc.			Holdings Ltd.			-2
	Guarantor)			(Subsidiary			Subsidiaries
				Issuer)			and
							Eliminations
							(Non-guarantor
							Subsidiaries)
							-1
Comprehensive income (loss)
Net income (loss)	$	532,718		$	(11,161	)	$	709,600		$	(544,901	)	$	686,256
Change in net unrealized gains on investments	—			—			(715		)	—			(715		)
Comprehensive income (loss)	532,718			(11,161		)	708,885			(544,901		)	685,541
Net income attributable to noncontrolling interests	—			—			(153,538		)	—			(153,538		)
Comprehensive income attributable to noncontrolling interests	—			—			(153,538		)	—			(153,538		)
Comprehensive income (loss) attributable to RenaissanceRe	$	532,718		$	(11,161	)	$	555,347		$	(544,901	)	$	532,003
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement of Operations	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
for the year ended December 31, 2013	Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
	(Parent			Holdings Inc.			Holdings Ltd.			-2
	Guarantor)			(Subsidiary			Subsidiaries
				Issuer)			and
							Eliminations
							(Non-guarantor
							Subsidiaries)
							-1
Revenues
Net premiums earned	$	—		$	—		$	1,114,626		$	—		$	1,114,626
Net investment income	4,213			488			209,105			(5,778		)	208,028
Net foreign exchange (losses) gains	(7		)	(2		)	1,926			—			1,917
Equity in earnings of other ventures	—			—			23,194			—			23,194
Other income (loss)	106			125			(2,590		)	—			(2,359		)
Net realized and unrealized (losses) gains on investments	(483		)	1,196			34,363			—			35,076
Total revenues	3,829			1,807			1,380,624			(5,778		)	1,380,482
Expenses
Net claims and claim expenses incurred	—			—			171,287			—			171,287
Acquisition expenses	—			—			125,501			—			125,501
Operational expenses	(4,962		)	7,566			189,117			(616		)	191,105
Corporate expenses	31,264			338			2,020			—			33,622
Interest expense	734			14,467			2,728			—			17,929
Total expenses	27,036			22,371			490,653			(616		)	539,444
Loss (income) before equity in net loss of subsidiaries and taxes	(23,207		)	(20,564		)	889,971			(5,162		)	841,038
Equity in net income of subsidiaries	713,831			2,142			—			(715,973		)	—
Income (loss) from continuing operations before taxes	690,624			(18,422		)	889,971			(721,135		)	841,038
Income tax expense	—			(1,558		)	(134		)	—			(1,692		)
Income (loss) from continuing operations	690,624			(19,980		)	889,837			(721,135		)	839,346
Income from discontinued operations	—			2,422			—			—			2,422
Net income (loss)	690,624			(17,558		)	889,837			(721,135		)	841,768
Net income attributable to noncontrolling interest	—			—			(151,144		)	—			(151,144		)
Net income (loss) attributable to RenaissanceRe	690,624			(17,558		)	738,693			(721,135		)	690,624
Dividends on preference shares	(24,948		)	—			—			—			(24,948		)
Net income (loss) available (attributable) to RenaissanceRe common shareholders	$	665,676		$	(17,558	)	$	738,693		$	(721,135	)	$	665,676
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement of Comprehensive Income (Loss) for the year ended December 31, 2013	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
	Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
	(Parent			Holdings Inc.			Holdings Ltd.			-2
	Guarantor)			(Subsidiary			Subsidiaries
				Issuer)			and
							Eliminations
							(Non-guarantor
							Subsidiaries)
							-1
Comprehensive income (loss)
Net income (loss)	$	690,624		$	(17,558	)	$	889,837		$	(721,135	)	$	841,768
Change in net unrealized gains on investments	—			—			(9,491		)	—			(9,491		)
Comprehensive income (loss)	690,624			(17,558		)	880,346			(721,135		)	832,277
Net income attributable to noncontrolling interests	—			—			(151,144		)	—			(151,144		)
Comprehensive income attributable to noncontrolling interests	—			—			(151,144		)	—			(151,144		)
Comprehensive income (loss) available (attributable) to RenaissanceRe	$	690,624		$	(17,558	)	$	729,202		$	(721,135	)	$	681,133
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement of Operations	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
for the year ended December 31, 2012	Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
	(Parent			Holdings Inc.			Holdings Ltd.			-2
	Guarantor)			(Subsidiary			Subsidiaries
				Issuer)			and
							Eliminations
							(Non-guarantor
							Subsidiaries)
							-1
Revenues
Net premiums earned	$	—		$	—		$	1,069,355		$	—		$	1,069,355
Net investment income	14,195			619			150,911			—			165,725
Net foreign exchange gains	33			—			5,286			—			5,319
Equity in earnings of other ventures	—			—			23,238			—			23,238
Other income (loss)	2,822			—			(4,942		)	—			(2,120		)
Net realized and unrealized gains on investments	14,862			1,556			146,703			—			163,121
Net other-than-temporary impairments	—			—			(343		)	—			(343		)
Total revenues	31,912			2,175			1,390,208			—			1,424,295
Expenses
Net claims and claim expenses incurred	—			—			325,211			—			325,211
Acquisition expenses	—			—			113,542			—			113,542
Operational expenses	(5,103		)	7,013			177,241			—			179,151
Corporate expenses	14,282			273			1,901			—			16,456
Interest expense	5,875			14,467			2,755			—			23,097
Total expenses	15,054			21,753			620,650			—			657,457
Income (loss) before equity in net loss of subsidiaries and taxes	16,858			(19,578		)	769,558			—			766,838
Equity in net earnings of subsidiaries	584,051			1,860			—			(585,911		)	—
Income (loss) from continuing operations before taxes	600,909			(17,718		)	769,558			(585,911		)	766,838
Income tax expense	—			(499		)	(914		)	—			(1,413		)
Income (loss) from continuing operations	600,909			(18,217		)	768,644			(585,911		)	765,425
Loss from discontinued operations	—			(16,476		)	—			—			(16,476		)
Net income (loss)	600,909			(34,693		)	768,644			(585,911		)	748,949
Net income attributable to noncontrolling interest	—			—			(148,040		)	—			(148,040		)
Net income (loss) attributable to RenaissanceRe	600,909			(34,693		)	620,604			(585,911		)	600,909
Dividends on preference shares	(34,895		)	—			—			—			(34,895		)
Net income (loss) available (attributable) to RenaissanceRe common shareholders	$	566,014		$	(34,693	)	$	620,604		$	(585,911	)	$	566,014
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement of Comprehensive Income (Loss) for the year ended December 31, 2012	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
	Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
	(Parent			Holdings Inc.			Holdings Ltd.			-2
	Guarantor)			(Subsidiary			Subsidiaries
				Issuer)			and
							Eliminations
							(Non-guarantor
							Subsidiaries)
							-1
Comprehensive income (loss)
Net income (loss)	$	600,909		$	(34,693	)	$	768,644		$	(585,911	)	$	748,949
Change in net unrealized gains on investments	—			—			1,914			—			1,914
Portion of other-than-temporary impairments recognized in other comprehensive loss	—			—			(52		)	—			(52		)
Comprehensive income (loss)	600,909			(34,693		)	770,506			(585,911		)	750,811
Net income attributable to noncontrolling interests	—			—			(148,040		)	—			(148,040		)
Comprehensive income attributable to noncontrolling interests	—			—			(148,040		)	—			(148,040		)
Comprehensive income (loss) attributable to RenaissanceRe	$	600,909		$	(34,693	)	$	622,466		$	(585,911	)	$	602,771
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement of Cash Flows	RenaissanceRe			RenRe North			Other			RenaissanceRe
for the year ended December 31, 2014	Holdings Ltd.			America			RenaissanceRe			Consolidated
	(Parent			Holdings Inc.			Holdings Ltd.
	Guarantor)			(Subsidiary			Subsidiaries
				Issuer)			and
							Eliminations
							(Non-guarantor
							Subsidiaries)
							-1
Cash flows provided by (used in) operating activities
Net cash provided by (used in) operating activities	$	429		$	(18,114	)	$	678,342		$	660,657
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	88,273			20,487			7,573,813			7,682,573
Purchases of fixed maturity investments trading	(88,341		)	(14,969		)	(7,535,868		)	(7,639,178		)
Proceeds from sales and maturities of fixed maturity investments available for sale	—			—			7,088			7,088
Net sales (purchases) of equity investments trading	—			13,761			(33,764		)	(20,003		)
Net sales (purchases) of short term investments	73,717			225			(28,919		)	45,023
Net sales of other investments	—			—			59,120			59,120
Net sales of investments in other ventures	—			—			1,030			1,030
Net sales of other assets	—			—			6,000			6,000
Dividends and return of capital from subsidiaries	1,259,224			11,204			(1,270,428		)	—
Contributions to subsidiaries	(759,456		)	(12,625		)	772,081			—
Due to (from) subsidiary	6,315			(2,963		)	(3,352		)	—
Net cash provided by (used in) investing activities	579,732			15,120			(453,199		)	141,653
Cash flows used in financing activities
Dividends paid – RenaissanceRe common shares	(45,912		)	—			—			(45,912		)
Dividends paid – preference shares	(22,381		)	—			—			(22,381		)
RenaissanceRe common share repurchases	(514,678		)	—			—			(514,678		)
Net third party redeemable noncontrolling interest share transactions	—			—			(111,707		)	(111,707		)
Net cash used in financing activities	(582,971		)	—			(111,707		)	(694,678		)
Effect of exchange rate changes on foreign currency cash	—			—			9,920			9,920
Net (decrease) increase in cash and cash equivalents	(2,810		)	(2,994		)	123,356			117,552
Cash and cash equivalents, beginning of period	8,796			4,027			395,209			408,032
Cash and cash equivalents, end of period	$	5,986		$	1,033		$	518,565		$	525,584
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
Condensed Consolidating Statement of Cash Flows	RenaissanceRe			RenRe North			Other			RenaissanceRe
for the year ended December 31, 2013	Holdings Ltd.			America			RenaissanceRe			Consolidated
	(Parent			Holdings Inc.			Holdings Ltd.
	Guarantor)			(Subsidiary			Subsidiaries
				Issuer)			and
							Eliminations
							(Non-guarantor
							Subsidiaries)
							-1
Cash flows (used in) provided by operating activities
Net cash (used in) provided by operating activities	$	(37,966	)	$	(7,583	)	$	841,270		$	795,721
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	880,749			185,143			7,185,513			8,251,405
Purchases of fixed maturity investments trading	(491,768		)	(160,422		)	(7,814,277		)	(8,466,467		)
Proceeds from sales and maturities of fixed maturity investments available for sale	—			—			45,178			45,178
Net (purchases) sales of equity investments trading	—			(81,437		)	48,382			(33,055		)
Net sales (purchases) of short term investments	21,217			9,399			(277,587		)	(246,971		)
Net sales of other investments	—			—			76,214			76,214
Net purchases of investments in other ventures	—			—			(4,000		)	(4,000		)
Net sales of other assets	—			—			2,181			2,181
Dividends and return of capital from subsidiaries	504,241			83,593			(587,834		)	—
Contributions to subsidiaries	(500,652		)	(38,117		)	538,769			—
Due to (from) subsidiaries	17,446			(3,761		)	(13,685		)	—
Net proceeds related to sale of discontinued operations	—			—			60,000			60,000
Net cash provided by (used in) investing activities	431,233			(5,602		)	(741,146		)	(315,515		)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(49,267		)	—			—			(49,267		)
Dividends paid – preference shares	(24,948		)	—			—			(24,948		)
RenaissanceRe common share repurchases	(207,410		)	—			—			(207,410		)
Net repayment of debt	(100,000		)	—			(2,436		)	(102,436		)
Redemption 6.08% Series C preference shares	(125,000		)	—			—			(125,000		)
Redemption 6.60% Series D preference shares	(150,000		)	—			—			(150,000		)
Issuance of 5.375% Series E preference shares, net of expenses	265,856			—			—			265,856
Contribution of capital from parent	—			15,684			(15,684		)	—
Net third party redeemable noncontrolling interest share transactions	—			—			(5,750		)	(5,750		)
Net cash (used in) provided by financing activities	(390,769		)	15,684			(23,870		)	(398,955		)
Effect of exchange rate changes on foreign currency cash	—			—			1,423			1,423
Net increase in cash and cash equivalents	2,498			2,499			77,677			82,674
Net decrease in cash and cash equivalents of discontinued operations	—			—			21,213			21,213
Cash and cash equivalents, beginning of period	6,298			1,528			296,319			304,145
Cash and cash equivalents, end of period	$	8,796		$	4,027		$	395,209		$	408,032
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
Condensed Consolidating Statement of Cash Flows	RenaissanceRe			RenRe North			Other			RenaissanceRe
for the year ended December 31, 2012	Holdings Ltd.			America			RenaissanceRe			Consolidated
	(Parent			Holdings Inc.			Holdings Ltd.
	Guarantor)			(Subsidiary			Subsidiaries
				Issuer)			and
							Eliminations
							(Non-guarantor
							Subsidiaries)
							-1
Cash flows provided by (used in) operating activities
Net cash provided by (used in) operating activities	$	128,567		$	(10,376	)	$	598,738		$	716,929
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	744,211			140,626			7,308,030			8,192,867
Purchases of fixed maturity investments trading	(692,783		)	(73,800		)	(7,769,655		)	(8,536,238		)
Proceeds from sales and maturities of fixed maturity investments available for sale	—			—			65,168			65,168
Net (purchases) sales of short term investments	(80,485		)	(10,624		)	159,886			68,777
Net sales of other investments	—			—			150,828			150,828
Net purchases of other assets	—			—			(4,079		)	(4,079		)
Dividends and return of capital from subsidiaries	979,311			9,541			(988,852		)	—
Contributions to subsidiaries	(366,210		)	(50,000		)	416,210			—
Due (from) to subsidiary	(15,359		)	241			15,118			—
Net payments related to sale of discontinued operations	—			(9,000		)	—			(9,000		)
Net cash provided by (used in) investing activities	568,685			6,984			(647,346		)	(71,677		)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(53,356		)	—			—			(53,356		)
Dividends paid – preference shares	(34,895		)	—			—			(34,895		)
RenaissanceRe common share repurchases	(463,309		)	—			—			(463,309		)
Net repayment of debt	—			—			(1,937		)	(1,937		)
Redemption of 6.60% Series D preference shares	(150,000		)	—			—			(150,000		)
Third party DaVinciRe share repurchases	—			—			164,927			164,927
Net cash (used in) provided by financing activities	(701,560		)	—			162,990			(538,570		)
Effect of exchange rate changes on foreign currency cash	—			—			1,692			1,692
Net (decrease) increase in cash and cash equivalents	(4,308		)	(3,392		)	116,074			108,374
Net decrease in cash and cash equivalents of discontinued operations	—			—			13,946			13,946
Cash and cash equivalents, beginning of year	10,606			4,920			166,299			181,825
Cash and cash equivalents, end of year	$	6,298		$	1,528		$	296,319		$	304,145
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS
	During January 2015, DaVinciRe redeemed a portion of its outstanding shares from certain existing DaVinciRe shareholders, including the Company. The net redemption as a result of these transactions was $225.0 million. In connection with the redemption, DaVinciRe retained a $45.0 million holdback. The Company’s noncontrolling economic ownership in DaVinciRe subsequent to these transactions was 26.3%, effective January 1, 2015.
	During January 2015, Upsilon RFO returned capital to all of the investors who participated in risks incepting on January 1, 2014 and expiring on December 31, 2014, including the Company. The total amount of capital agreed to be returned is $352.8 million, with $317.5 million of this amount having been repaid during January 2015 and the remaining $35.3 million expected to be repaid prior to March 31, 2015.

Schedule_I_Summary_of_Investme

Schedule I. Summary of Investments Other Than Investments in Related Parties	12 Months Ended
	Dec. 31, 2014
Summary of Investments, Other than Investments in Related Parties [Abstract]
Summary of Investments, Other than Investments in Related Parties	SCHEDULE I
	RENAISSANCERE HOLDINGS LTD. AND SUBSIDIARIES
	SUMMARY OF INVESTMENTS
	OTHER THAN INVESTMENTS IN RELATED PARTIES
	(THOUSANDS OF UNITED STATES DOLLARS)
		December 31, 2014
		Amortized Cost		Market Value		Amount at
						which shown
						in the
						Balance Sheet
	Type of investment:
	Fixed maturity investments
	U.S. treasuries	$	1,672,441	$	1,671,471	$	1,671,471
	Agencies	96,271		96,208		96,208
	Non-U.S. government (Sovereign debt)	287,856		280,651		280,651
	Non-U.S. government-backed corporate	146,691		146,467		146,467
	Corporate	1,611,172		1,610,442		1,610,442
	Agency mortgage-backed	315,911		316,620		316,620
	Non-agency mortgage-backed	237,891		253,050		253,050
	Commercial mortgage-backed	377,792		381,051		381,051
	Asset-backed	27,360		27,610		27,610
	Total fixed maturity investments	$	4,773,385	4,783,570		4,783,570
	Short term investments			1,013,222		1,013,222
	Equity investments			322,098		322,098
	Other investments			504,147		504,147
	Investments in other ventures, under equity method			120,713		120,713
	Total investments			$	6,743,750	$	6,743,750

Schedule_II_Condensed_Financia

Schedule II. Condensed Financial Information Of Registrant	12 Months Ended
	Dec. 31, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Financial Information of Registrant	SCHEDULE II
	RENAISSANCERE HOLDINGS LTD.
	CONDENSED FINANCIAL INFORMATION OF REGISTRANT
	RENAISSANCERE HOLDINGS LTD.
	BALANCE SHEETS
	AT DECEMBER 31, 2014 AND 2013
	(PARENT COMPANY)
	(THOUSANDS OF UNITED STATES DOLLARS)
		At December 31,
		2014			2013
	Assets
	Short term investments, at fair value	$	137,006		$	210,719
	Cash and cash equivalents	5,986			8,796
	Investments in subsidiaries	3,509,974			3,294,729
	Due from subsidiaries	10,164			16,479
	Dividends due from subsidiaries	116,384			280,273
	Receivable for investments sold	10			14
	Other assets	112,400			112,234
	Total Assets	$	3,891,924		$	3,923,244
	Liabilities and Shareholders’ Equity
	Liabilities
	Contributions due to subsidiaries	$	6,000		$	—
	Other liabilities	20,209			18,860
	Total Liabilities	26,209			18,860
	Shareholders’ Equity
	Preference shares: $1.00 par value – 16,000,000 shares issued and outstanding at December 31, 2014 (December 31, 2013 – 16,000,000)	400,000			400,000
	Common shares: $1.00 par value – 38,441,972 shares issued and outstanding at December 31, 2014 (December 31, 2013 – 43,646,436)	38,442			43,646
	Accumulated other comprehensive income	3,416			4,131
	Retained earnings	3,423,857			3,456,607
	Total Shareholders’ Equity	3,865,715			3,904,384
	Total Liabilities and Shareholders’ Equity	$	3,891,924		$	3,923,244
	SCHEDULE II
	RENAISSANCERE HOLDINGS LTD.
	CONDENSED FINANCIAL INFORMATION OF REGISTRANT – CONTINUED
	RENAISSANCERE HOLDINGS LTD.
	STATEMENTS OF OPERATIONS
	FOR THE YEARS ENDED DECEMBER 31, 2014, 2013 AND 2012
	(PARENT COMPANY)
	(THOUSANDS OF UNITED STATES DOLLARS)
		Year ended December 31,
		2014			2013			2012
	Revenues
	Net investment income	$	2,706		$	4,213		$	14,195
	Net foreign exchange gains (losses)	(13		)	(7		)	33
	Other income	—			106			2,822
	Net realized and unrealized gains (losses) on investments	83			(483		)	14,862
	Total revenues	2,776			3,829			31,912
	Expenses
	Interest expense	—			734			5,875
	Operational expenses	(4,890		)	(4,962		)	(5,103		)
	Corporate expenses	20,787			31,264			14,282
	Total expenses	15,897			27,036			15,054
	(Loss) income before equity in net income of subsidiaries and taxes	(13,121		)	(23,207		)	16,858
	Equity in net income of subsidiaries	545,839			713,831			584,051
	Net income	532,718			690,624			600,909
	Dividends on preference shares	(22,381		)	(24,948		)	(34,895		)
	Net income available to RenaissanceRe common shareholders	$	510,337		$	665,676		$	566,014
	RENAISSANCERE HOLDINGS LTD.
	STATEMENTS OF COMPREHENSIVE INCOME
	FOR THE YEARS ENDED DECEMBER 31, 2014, 2013 AND 2012
	(PARENT COMPANY)
	(THOUSANDS OF UNITED STATES DOLLARS)
		Year ended December 31,
		2014			2013			2012
Comprehensive income
Net income	$	532,718		$	690,624		$	600,909
Comprehensive income attributable to RenaissanceRe	$	532,718		$	690,624		$	600,909
SCHEDULE II
RENAISSANCERE HOLDINGS LTD.
CONDENSED FINANCIAL INFORMATION OF REGISTRANT – CONTINUED
RENAISSANCERE HOLDINGS LTD.
STATEMENTS OF CASH FLOWS
FOR THE YEARS ENDED DECEMBER 31, 2014, 2013 AND 2012
(PARENT COMPANY)
(THOUSANDS OF UNITED STATES DOLLARS)
	Year ended December 31,
	2014			2013			2012
Cash flows (used in) provided by operating activities:
Net income	$	532,718		$	690,624		$	600,909
Less: equity in net income of subsidiaries	(545,839		)	(713,831		)	(584,051		)
	(13,121		)	(23,207		)	16,858
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Net unrealized losses included in net investment income	—			—			348
Net unrealized gains included in other loss	—			(20		)	(193		)
Net realized and unrealized (gains) losses on investments	(83		)	483			(14,862		)
Other	13,633			(15,222		)	126,416
Net cash provided by (used in) operating activities	429			(37,966		)	128,567
Cash flows provided by investing activities:
Proceeds from maturities and sales of fixed maturity investments trading	88,273			880,749			744,211
Purchases of fixed maturity investments trading	(88,341		)	(491,768		)	(692,783		)
Net sales (purchases) of short term investments	73,717			21,217			(80,485		)
Dividends and return of capital from subsidiaries	1,259,224			504,241			979,311
Contributions to subsidiaries	(759,456		)	(500,652		)	(366,210		)
Due to (from) subsidiary	6,315			17,446			(15,359		)
Net cash provided by investing activities	579,732			431,233			568,685
Cash flows used in financing activities:
Dividends paid – RenaissanceRe common shares	(45,912		)	(49,267		)	(53,356		)
Dividends paid – preference shares	(22,381		)	(24,948		)	(34,895		)
RenaissanceRe common share repurchases	(514,678		)	(207,410		)	(463,309		)
Redemption of 6.08% Series C preference shares	—			(125,000		)	—
Redemption of 6.60% Series D preference shares	—			(150,000		)	(150,000		)
Issuance of 5.375% Series E preference share, net of expenses	—			265,856			—
Net repayment of debt	—			(100,000		)	—
Net cash used in financing activities	(582,971		)	(390,769		)	(701,560		)
Net (decrease) increase in cash and cash equivalents	(2,810		)	2,498			(4,308		)
Cash and cash equivalents, beginning of year	8,796			6,298			10,606
Cash and cash equivalents, end of year	$	5,986		$	8,796		$	6,298

Schedule_III_Supplementary_Ins

Schedule III. Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2014
Supplementary Insurance Information [Abstract]
Supplementary Insurance Information	SCHEDULE III
	RENAISSANCERE HOLDINGS LTD. AND SUBSIDIARIES
	SUPPLEMENTARY INSURANCE INFORMATION
	(THOUSANDS OF UNITED STATES DOLLARS)
		December 31, 2014						Year ended December 31, 2014
		Deferred		Future Policy		Unearned		Premium			Net		Benefits,			Amortization			Other		Net Written
		Policy		Benefits,		Premiums		Revenue			Investment		Claims,			of Deferred			Operating		Premiums
		Acquisition		Losses,							Income		Losses and			Policy			Expenses
		Costs		Claims and									Settlement			Acquisition
				Loss Expenses									Expenses			Costs
	Catastrophe Reinsurance	$	28,057	$	542,667	$	222,864	$	590,845		$	—	$	1,757		$	43,161		$	95,851	$	541,608
	Specialty Reinsurance	58,758		543,710		184,054		253,537			—		88,502			60,936			43,370		295,855
	Lloyd’s	23,244		284,447		105,468		217,666			—		113,825			46,927			51,115		230,429
	Other	—		41,686		—		368			124,316		(6,137		)	(6,548		)	303		344
	Total	$	110,059	$	1,412,510	$	512,386	$	1,062,416		$	124,316	$	197,947		$	144,476		$	190,639	$	1,068,236
		December 31, 2013						Year ended December 31, 2013
		Deferred		Future Policy		Unearned		Premium			Net		Benefits,			Amortization			Other		Net Written
		Policy		Benefits,		Premiums		Revenue			Investment		Claims,			of Deferred			Operating		Premiums
		Acquisition		Losses,							Income		Losses and			Policy			Expenses
		Costs		Claims and									Settlement			Acquisition
				Loss Expenses									Expenses			Costs
	Catastrophe Reinsurance	$	37,889	$	780,987	$	279,465	$	723,705		$	—	$	7,908		$	49,161		$	108,130	$	753,078
	Specialty Reinsurance	26,727		506,268		115,278		214,306			—		67,236			41,538			31,780		248,562
	Lloyd’s	17,068		218,367		83,145		176,029			—		95,693			34,823			50,540		201,697
	Other	—		58,108		—		586			208,028		450			(21		)	655		610
	Total	$	81,684	$	1,563,730	$	477,888	$	1,114,626		$	208,028	$	171,287		$	125,501		$	191,105	$	1,203,947
		31-Dec-12						Year ended December 31, 2012
		Deferred		Future Policy		Unearned		Premium			Net		Benefits,			Amortization			Other		Net Written
		Policy		Benefits,		Premiums		Revenue			Investment		Claims,			of Deferred			Operating		Premiums
		Acquisition		Losses,							Income		Losses and			Policy			Expenses
		Costs		Claims and									Settlement			Acquisition
				Loss Expenses									Expenses			Costs
	Catastrophe Reinsurance	$	28,306	$	1,184,258	$	261,456	$	781,738		$	—	$	165,209		$	66,665		$	103,811	$	766,035
	Specialty Reinsurance	15,010		478,313		84,058		164,685			—		76,813			23,826			29,124		201,552
	Lloyd’s	9,306		149,470		54,003		122,968			—		80,242			22,864			45,680		135,131
	Other	—		67,336		—		(36		)	165,725		2,947			187			536		(61		)
	Total	$	52,622	$	1,879,377	$	399,517	$	1,069,355		$	165,725	$	325,211		$	113,542		$	179,151	$	1,102,657

Schedule_IV_Supplemental_Sched

Schedule IV. Supplemental Schedule of Reinsurance Premiums	12 Months Ended
	Dec. 31, 2014
Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Abstract]
Supplemental Schedule of Reinsurance Premiums	SCHEDULE IV
	RENAISSANCERE HOLDINGS LTD. AND SUBSIDIARIES
	SUPPLEMENTAL SCHEDULE OF REINSURANCE PREMIUMS
	(THOUSANDS OF UNITED STATES DOLLARS)
		Gross		Ceded to		Assumed		Net Amount		Percentage
		Amounts		Other		From Other				of Amount
				Companies		Companies				Assumed
										to Net
	Year ended December 31, 2014
	Property and liability premiums earned	$	66,027	$	453,658	$	1,450,047	$	1,062,416	136	%
	Year ended December 31, 2013
	Property and liability premiums earned	$	44,530	$	412,415	$	1,482,511	$	1,114,626	133	%
	Year ended December 31, 2012
	Property and liability premiums earned	$	34,028	$	430,374	$	1,465,701	$	1,069,355	137	%

Schedule_VI_Supplementary_Insu

Schedule VI. Supplementary Insurance Information Concerning Property-Casualty Insurance Operations	12 Months Ended
	Dec. 31, 2014
Supplemental Information for Property, Casualty Insurance Underwriters [Abstract]
Supplemental Insurance Information Concerning Property-Casualty Insurance Operations	SCHEDULE VI
	RENAISSANCERE HOLDINGS LTD. AND SUBSIDIARIES
	SUPPLEMENTARY INSURANCE INFORMATION CONCERNING
	PROPERTY-CASUALTY INSURANCE OPERATIONS
	(THOUSANDS OF UNITED STATES DOLLARS)
	Affiliation with Registrant	Deferred		Reserves for			Discount, if		Unearned		Earned		Net
		Policy		Unpaid Claims			any,		Premiums		Premiums		Investment
		Acquisition		and Claim			Deducted						Income
		Costs		Adjustment
				Expenses
	Consolidated Subsidiaries
	Year ended December 31, 2014	$	110,059	$	1,412,510		$	—	$	512,386	$	1,062,416	$	124,316
	Year ended December 31, 2013	$	81,684	$	1,563,730		$	—	$	477,888	$	1,114,626	$	208,028
	Year ended December 31, 2012	$	52,622	$	1,879,377		$	—	$	399,517	$	1,069,355	$	165,725
		Claims and Claim Adjustment Expenses Incurred Related to					Amortization		Paid Claims		Net
							of Deferred		and Claim		Premiums
							Policy		Adjustment		Written
							Acquisition		Expenses
	Affiliation with Registrant	Current Year		Prior Year			Costs
	Consolidated Subsidiaries
	Year ended December 31, 2014	$	341,745	$	(143,798	)	$	144,476	$	314,836	$	1,068,236
	Year ended December 31, 2013	$	315,241	$	(143,954	)	$	125,501	$	395,447	$	1,203,947
	Year ended December 31, 2012	$	483,180	$	(157,969	)	$	113,542	$	226,671	$	1,102,657

Significant_Accounting_Policie1

Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation	BASIS OF PRESENTATION
	These consolidated financial statements have been prepared on the basis of accounting principles generally accepted in the United States (“GAAP”). All significant intercompany accounts and transactions have been eliminated from these statements. Except as discussed in “Note 3. Discontinued Operations,” and unless otherwise noted, the notes to the consolidated financial statements reflect the Company’s continuing operations.
	Certain comparative information has been reclassified to conform to the current presentation.
Use of Estimates in Financial Statements	USE OF ESTIMATES IN FINANCIAL STATEMENTS
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported and disclosed 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. Actual results could differ materially from those estimates. The major estimates reflected in the Company’s consolidated financial statements include, but are not limited to, the reserve for claims and claim expenses; reinsurance recoverables, including allowances for reinsurance recoverables deemed uncollectible; estimates of written and earned premiums; fair value, including the fair value of investments, financial instruments and derivatives; impairment charges; and the Company’s deferred tax valuation allowance.
Discontinued Operations	DISCONTINUED OPERATIONS
	The results of operations of substantially all of the Company’s U.S.-based insurance operations and REAL, its U.S.-based weather and weather-related energy risk management unit, each of which has been sold to a separate unaffiliated third party, are classified as held for sale and are reported as discontinued operations in accordance with FASB ASC Topic Discontinued Operations. The consolidated financial statements and notes thereto are presented excluding the operations and cash flows of the discontinued operations from the continuing operations of the Company since the Company will not have any significant continuing involvement in the operations after the sale. The financial position and results of operations of discontinued operations are presented as single line items on the consolidated balance sheets and statements of operations, respectively.
Premiums and Related Expenses	PREMIUMS AND RELATED EXPENSES
	Premiums are recognized as income, net of any applicable reinsurance or retrocessional coverage purchased, over the terms of the related contracts and policies. Premiums written are based on contract and policy terms and include estimates based on information received from both insureds and ceding companies. Subsequent differences arising on such estimates are recorded in the period in which they are determined. Unearned premiums represents the portion of premiums written that relate to the unexpired terms of contracts and policies in force. Amounts are computed by pro rata methods based on statistical data or reports received from ceding companies. Reinstatement premiums are estimated after the occurrence of a significant loss and are recorded in accordance with the contract terms based upon paid losses and case reserves. Reinstatement premiums are earned when written.
	Acquisition costs are incurred when a contract or policy is issued and only the costs directly related to the successful acquisition of new and renewal contract or policies are deferred and amortized over the same period in which the related premiums are earned. Acquisition costs are shown net of commissions and profit commissions earned on ceded reinsurance, and consist principally of commissions, brokerage and premium tax expenses incurred at the time a contract or policy is issued. Deferred policy acquisition costs are limited to their estimated realizable value based on the related unearned premiums. Anticipated claims and claim expenses, based on historical and current experience, and anticipated investment income related to those premiums are considered in determining the recoverability of deferred acquisition costs.
Claims and Claim Expenses	CLAIMS AND CLAIM EXPENSES
	The reserve for claims and claim expenses includes estimates for unpaid claims and claim expenses on reported losses as well as an estimate of losses incurred but not reported. The reserve is based on individual claims, case reserves and other reserve estimates reported by insureds and ceding companies as well as management estimates of ultimate losses. Inherent in the estimates of ultimate losses are expected trends in claim severity and frequency and other factors which could vary significantly as claims are settled. Also, during the past few years, the Company has increased its specialty reinsurance business, but does not have the benefit of a significant amount of its own historical experience in certain of these lines of business. Accordingly, the setting and reserving for incurred losses in these lines of business could be subject to greater variability.
	Ultimate losses may vary materially from the amounts provided in the consolidated financial statements. These estimates are reviewed regularly and, as experience develops and new information becomes known, the reserves are adjusted as necessary. Such adjustments, if any, are reflected in the consolidated statements of operations in the period in which they become known and are accounted for as changes in estimates.
Reinsurance	REINSURANCE
	Amounts recoverable from reinsurers are estimated in a manner consistent with the claim liability associated with the reinsured policies. For multi-year retrospectively rated contracts, the Company accrues amounts (either assets or liabilities) that are due to or from assuming companies based on estimated contract experience. If the Company determines that adjustments to earlier estimates are appropriate, such adjustments are recorded in the period in which they are determined. Reinsurance recoverables on dual trigger reinsurance contracts require the Company to estimate its ultimate losses applicable to these contracts as well as estimate the ultimate amount of insured industry losses that will be reported by the applicable statistical reporting agency, as per the contract terms. Amounts recoverable from reinsurers are recorded net of a valuation allowance for estimated uncollectible recoveries.
	Assumed and ceded reinsurance contracts that lack a significant transfer of risk are treated as deposits.
	Certain assumed and ceded reinsurance contracts that do not meet all of the criteria to be accounted for as reinsurance in accordance with FASB ASC Topic Financial Services - Insurance have been accounted for at fair value under the fair value option in accordance with FASB ASC Topic Financial Instruments.
Fixed Maturity Investments, Equity Investments and Short Term Investments	INVESTMENTS, CASH AND CASH EQUIVALENTS
	Fixed Maturity Investments
	Investments in fixed maturities are classified as available for sale or trading and are reported at fair value. Investment transactions are recorded on the trade date with balances pending settlement reflected in the balance sheet as a receivable for investments sold or a payable for investments purchased. Net investment income includes interest and dividend income together with amortization of market premiums and discounts and is net of investment management and custody fees. The amortization of premium and accretion of discount for fixed maturity securities is computed using the effective yield method. For mortgage-backed securities and other holdings for which there is prepayment risk, prepayment assumptions are evaluated quarterly and revised as necessary. Any adjustments required due to the change in effective yields and maturities are recognized on a prospective basis through yield adjustments. Fair values of investments are based on quoted market prices, or when such prices are not available, by reference to broker or underwriter bid indications and/or internal pricing valuation techniques. The net unrealized appreciation or depreciation on fixed maturity investments available for sale is included in accumulated other comprehensive income. The net unrealized appreciation or depreciation on fixed maturity investments trading is included in net realized and unrealized gains on investments in the consolidated statements of operations. Realized gains or losses on the sale of investments are determined on the basis of the first in first out cost method and, for fixed maturity investments available for sale, include adjustments to the cost basis of investments for declines in value that are considered to be other-than-temporary.
	Other-Than-Temporary Impairments
	The Company recognizes other-than-temporary impairments in earnings for its impaired fixed maturity securities available for sale (i) for which the Company has the intent to sell the security or (ii) it is more likely than not that the Company will be required to sell the debt security before its anticipated recovery and (iii) for those securities which have a credit loss. In assessing whether a credit loss exists, the Company compares the present value of the cash flows expected to be collected from the security with the amortized cost basis of the security. In instances in which a determination is made that an impairment exists but the Company does not intend to sell the security and it is not more likely than not that the Company will be required to sell the security before the anticipated recovery of its remaining amortized cost basis, the impairment is separated into (i) the amount of the total impairment related to the credit loss and (ii) the amount of the total impairment related to all other factors. The amount of the total other-than-temporary impairment related to the credit loss is recognized in earnings. The amount of the total other-than-temporary impairment related to all other factors is recognized in other comprehensive income. In periods after the recognition of other-than-temporary impairments on the Company’s fixed maturity securities available for sale, the Company accounts for such securities as if they had been purchased on the measurement date of the other-than-temporary impairment at an amortized cost basis equal to the previous amortized cost basis less the other-than-temporary impairment recognized in earnings. For debt securities in which other-than-temporary impairments were recognized in earnings, the difference between the new amortized cost basis and the cash flows expected to be collected will be amortized into net investment income.
	Short Term Investments
	Short term investments, which are managed as part of the Company’s investment portfolio and have a maturity of one year or less when purchased, are carried at amortized cost, which approximates fair value. The net unrealized appreciation or depreciation on short term investments is included in net realized and unrealized gains on investments in the consolidated statements of operations.
	Equity Investments, Classified as Trading
	Equity investments are accounted for at fair value in accordance with FASB ASC Topic Financial Instruments. Fair values are primarily priced by pricing services, reflecting the closing price quoted for the final trading day of the period. Net investment income includes dividend income and the net realized and unrealized appreciation or depreciation on equity investments is included in net realized and unrealized gains on investments in the consolidated statements of operations.
Other Investments	Other Investments
	The Company accounts for its other investments at fair value in accordance with FASB ASC Topic Financial Instruments. The fair value of certain of the Company’s fund investments, which principally include private equity funds, a senior secured bank loan fund and hedge funds, is recorded on its balance sheet in other investments, and is generally established on the basis of the net valuation criteria established by the managers of such investments, if applicable. The net valuation criteria established by the managers of such investments is established in accordance with the governing documents of such investments. Certain of the Company’s fund managers, fund administrators, or both, are unable to provide final fund valuations as of the Company’s current reporting date. The typical reporting lag experienced by the Company to receive a final net asset value report is one month for hedge funds and senior secured bank loan funds and three months for private equity funds, although, in the past, in respect of certain of the Company’s private equity funds, the Company has on occasion experienced delays of up to six months at year end, as the private equity funds typically complete their respective year-end audits before releasing their final net asset value statements.
	In circumstances where there is a reporting lag between the current period end reporting date and the reporting date of the latest fund valuation, the Company estimates the fair value of these funds by starting with the prior month or quarter-end fund valuations, adjusting these valuations for actual capital calls, redemptions or distributions, as well as the impact of changes in foreign currency exchange rates, and then estimating the return for the current period. In circumstances in which the Company estimates the return for the current period, all information available to the Company is utilized. This principally includes preliminary estimates reported to the Company by its fund managers, obtaining the valuation of underlying portfolio investments where such underlying investments are publicly traded and therefore have a readily observable price, using information that is available to the Company with respect to the underlying investments, reviewing various indices for similar investments or asset classes, as well as estimating returns based on the results of similar types of investments for which the Company has obtained reported results, or other valuation methods, where possible. Actual final fund valuations may differ, perhaps materially so, from the Company’s estimates and these differences are recorded in the Company’s statement of operations in the period in which they are reported to the Company as a change in estimate.
	The Company’s other investments also include investments in catastrophe bonds which are recorded at fair value and based on broker or underwriter bid indications.
Investments in Other Ventures	Investments in Other Ventures
	Investments in which the Company has significant influence over the operating and financial policies of the investee are classified as investments in other ventures, under equity method, and are accounted for under the equity method of accounting. Under this method, the Company records its proportionate share of income or loss from such investments in its results for the period. Any decline in value of investments in other ventures, under equity method considered by management to be other-than-temporary is charged to income in the period in which it is determined.
Cash and Cash Equivalents	Cash and Cash Equivalents
	Cash equivalents include money market instruments with a maturity of ninety days or less when purchased.
Stock Incentive Compensation	STOCK INCENTIVE COMPENSATION
	The Company is authorized to issue restricted stock awards and units, performance shares, stock options and other equity-based awards to its employees and directors. The fair value of the compensation cost is measured at the grant date and expensed over the period for which the employee is required to provide services in exchange for the award.
	In addition, the Company is authorized to issue cash settled restricted stock units (“CSRSU”) to its employees. The fair value of CSRSUs is determined at each reporting date using observable exchange traded prices for the Company’s common shares and is expensed over the period for which the employee is required to provide service in exchange for the award. In addition, the fair value of the award is recorded on the Company’s consolidated balance sheet as a liability as it is expensed and until the point payment is made to the employee.
	Forfeiture benefits are estimated on a quarterly basis and incorporated in the determination of stock-based compensation.
Derivatives	DERIVATIVES
	The Company enters into derivative instruments such as futures, options, swaps, forward contracts and other derivative contracts in order to manage its foreign currency exposure, obtain exposure to a particular financial market, for yield enhancement, or for trading and speculation. The Company accounts for its derivatives in accordance with FASB ASC Topic Derivatives and Hedging, which requires all derivatives to be recorded at fair value on the Company’s balance sheet as either assets or liabilities, depending on their rights or obligations, with changes in fair value reflected in current earnings. The Company does not currently apply hedge accounting. The fair value of the Company’s derivatives is estimated by reference to quoted prices or broker quotes, where available, or in the absence of quoted prices or broker quotes, the use of industry or internal valuation models.
Fair Value	FAIR VALUE
	The Company accounts for certain of its assets and liabilities at fair value in accordance with FASB ASC Topic Fair Value Measurements and Disclosures.  The Company recognizes the change in unrealized gains and losses arising from changes in fair value in its statements of operations, with the exception of changes in unrealized gains and losses on its fixed maturity investments available for sale, which are recognized as a component of accumulated other comprehensive income (loss) in shareholders’ equity.
	The use of fair value to measure certain assets and liabilities with resulting unrealized gains or losses is pervasive within the Company’s consolidated financial statements. Fair value is defined under accounting guidance currently applicable to the Company to be the price that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between open market participants at the measurement date. The Company recognizes the change in unrealized gains and losses arising from changes in fair value in its consolidated statements of operations, with the exception of changes in unrealized gains and losses on its fixed maturity investments available for sale, which are recognized as a component of accumulated other comprehensive income in shareholders’ equity.
	FASB ASC Topic Fair Value Measurements and Disclosures prescribes a fair value hierarchy that prioritizes the inputs to the respective valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to valuation techniques that use at least one significant input that is unobservable (Level 3). The three levels of the fair value hierarchy are described below:
	•	Fair values determined by Level 1 inputs utilize unadjusted quoted prices obtained from active markets for identical assets or liabilities for which the Company has access. The fair value is determined by multiplying the quoted price by the quantity held by the Company;
	•	Fair values determined by Level 2 inputs utilize inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar assets and liabilities in active markets, and inputs other than quoted prices that are observable for the asset or liability, such as interest rates and yield curves that are observable at commonly quoted intervals, broker quotes and certain pricing indices; and
	•	Level 3 inputs are based all or in part on significant unobservable inputs for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability. In these cases, significant management assumptions can be used to establish management’s best estimate of the assumptions used by other market participants in determining the fair value of the asset or liability.
	In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy within which the fair value measurement in its entirety falls has been determined based on the lowest level input that is significant to the fair value measurement of the asset or liability. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and the Company considers factors specific to the asset or liability.
	In order to determine if a market is active or inactive for a security, the Company considers a number of factors, including, but not limited to, the spread between what a seller is asking for a security and what a buyer is bidding for the same security, the volume of trading activity for the security in question, the price of the security compared to its par value (for fixed maturity investments), and other factors that may be indicative of market activity.
	Other than the transaction noted below, there have been no material changes in the Company’s valuation techniques, nor have there been any transfers between Level 1 and Level 2, or Level 2 and Level 3 during the period represented by these consolidated financial statements.
Business Combinations	BUSINESS COMBINATIONS, GOODWILL AND OTHER INTANGIBLE ASSETS
	The Company accounts for business combinations in accordance with FASB ASC Topic Business Combinations, and goodwill and other intangible assets that arise from business combinations in accordance with FASB ASC Topic Intangibles – Goodwill and Other.
Goodwill and Other Intangible Assets	A purchase price that is in excess of the fair value of the net assets acquired arising from a business combination is recorded as goodwill, and is not amortized. Other intangible assets with a finite life are amortized over the estimated useful life of the asset. Other intangible assets with an indefinite useful life are not amortized.
	Goodwill and other indefinite life intangible assets are tested for impairment on an annual basis or more frequently if events or changes in circumstances indicate that the carrying amount may not be recoverable. Definite life intangible assets are reviewed for indicators of impairment on an annual basis or more frequently if events or changes in circumstances indicate that the carrying amount may not be recoverable, and tested for impairment if appropriate. For purposes of the annual impairment evaluation, goodwill is assigned to the applicable reporting unit of the acquired entities giving rise to the goodwill. Goodwill and other intangible assets recorded in connection with investments accounted for under the equity method, are recorded as “Investments in other ventures, under equity method” on the Company’s consolidated balance sheets.
	The Company has established the beginning of the fourth quarter as the date for performing its annual impairment tests. The Company has the option to first assess qualitative factors to determine whether it is necessary to perform the quantitative goodwill impairment test. Under this option, the Company would not be required to calculate the fair value of a reporting unit unless the Company determines, based on its qualitative assessment, that it is more likely than not that a reporting unit’s fair value is less than its carrying amount. If goodwill or other intangible assets are impaired, they are written down to their estimated fair value with a corresponding expense reflected in the Company’s consolidated statements of operations.
Noncontrolling Interests	NONCONTROLLING INTERESTS
	The Company accounts for noncontrolling interests in the shareholders’ equity section of the Company’s consolidated balance sheet in accordance with FASB ASC Topic Consolidations, and presents such noncontrolling shareholders’ interest in the net assets of the subsidiary. Net (income) loss attributable to noncontrolling interests is presented separately in the Company’s consolidated statements of operations.
	In addition, the Company accounts for redeemable noncontrolling interest in DaVinciRe in the mezzanine section of the Company’s consolidated balance sheet in accordance with United States Securities and Exchange Commission (“SEC”) guidance which is applicable to SEC registrants. The SEC guidance requires shares, not required to be accounted for in accordance with FASB ASC Topic Distinguishing Liabilities from Equity, and having redemption features that are not solely within the control of the issuer, to be classified outside of permanent equity in the mezzanine section of the balance sheet. Because the share classes related to the redeemable noncontrolling interest portion of DaVinciRe are not considered liabilities in accordance with FASB ASC Topic Distinguishing Liabilities from Equity and have redemption features that are not solely within the control of DaVinciRe, the redeemable noncontrolling interest in DaVinciRe is presented in the mezzanine section on the Company’s consolidated balance sheet in accordance with the SEC guidance noted above. The SEC guidance does not impact the accounting for redeemable noncontrolling interest on the consolidated statements of operations; therefore, the provisions of FASB ASC Topic Consolidation with respect to the consolidated statements of operations still apply.
Variable Interest Entities	VARIABLE INTEREST ENTITIES
	The Company accounts for VIEs in accordance with FASB ASC Topic Consolidation, which requires the consolidation of all VIEs by the primary beneficiary, that being the investor that has the power to direct the activities of the VIE and that will absorb a majority of the VIE’s expected losses or residual returns. The Company determines whether it is the primary beneficiary of a VIE by performing an analysis that principally considers: (i) the VIE’s purpose and design, including the risks the VIE was designed to create and pass through to its variable interest holders; (ii) the VIE’s capital structure; (iii) the terms between the VIE and its variable interest holders and other parties involved with the VIE; (iv) which variable interest holders have the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance; (v) which variable interest holders have the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE; and (vi) related party relationships. The Company reassesses its initial determination of whether the Company is the primary beneficiary of a VIE upon changes in facts and circumstances that could potentially alter the Company’s assessment.
Earnings Per Share	EARNINGS PER SHARE
	The Company calculates earnings per share in accordance with FASB ASC Topic Earnings per Share. Basic earnings per share are based on weighted average common shares and exclude any dilutive effects of options and restricted stock. Diluted earnings per share assumes the exercise of all dilutive stock options and restricted stock grants.
	The two-class method is used to determine earnings per share based on dividends declared on common shares and participating securities (i.e., distributed earnings) and participation rights of participating securities in any undistributed earnings. Each unvested restricted share granted by the Company to its employees is considered a participating security and the Company uses the two-class method to calculate its net income (loss) available (attributable) to RenaissanceRe common shareholders per common share – basic and diluted.
Foreign Exchange	FOREIGN EXCHANGE
	The Company’s functional currency is the U.S. dollar. Revenues and expenses denominated in foreign currencies are translated at the prevailing exchange rate at the transaction date. Monetary assets and liabilities denominated in foreign currencies are remeasured at exchange rates in effect at the balance sheet date, which may result in the recognition of exchange gains or losses which are included in the determination of net income (loss).
Taxation	TAXATION
	Income taxes have been provided in accordance with the provisions of FASB ASC Topic Income Taxes. Deferred tax assets and liabilities result from temporary differences between the amounts recorded in the consolidated financial statements and the tax basis of the Company’s assets and liabilities. Such temporary differences are primarily due to net operating loss carryforwards and GAAP versus tax basis accounting differences relating to interest expense, underwriting results, accrued expenses and investments. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance against deferred tax assets is recorded if it is more likely than not that all, or some portion, of the benefits related to deferred tax assets will not be realized.
Taxation, Uncertainties	Uncertain tax positions are also accounted for in accordance with FASB ASC Topic Income Taxes.  Uncertain tax positions must meet a more likely than not recognition threshold to be recognized.
Recently Adopted Accounting Pronouncements	RECENTLY ADOPTED ACCOUNTING PRONOUNCEMENTS
	Pushdown Accounting, a consensus of the FASB Emerging Issues Task Force
	In November 2014, the FASB issued ASU No. 2014-17, Pushdown Accounting, a consensus of the FASB Emerging Issues Task Force (“ASU 2014-17”). The objective of ASU 2014-17 is to provide guidance on whether and at what threshold an acquired entity that is a business or nonprofit activity can apply pushdown accounting in its separate financial statements. The amendments in ASU 2014-17 apply to the separate financial statements of an acquired entity and its subsidiaries that are a business or nonprofit activity (either public or nonpublic) upon the occurrence of an event in which an acquirer (an individual or an entity) obtains control of the acquired entity. The amendments in ASU 2014-17 provide an acquired entity with an option to apply pushdown accounting in its separate financial statements upon occurrence of an event in which an acquirer obtains control of the acquired entity. The amendments in ASU 2014-17 became effective on November 18, 2014. After the effective date, an acquired entity can make an election to apply the guidance to future change-in-control events or to its most recent change-in-control event. However, if the financial statements for the period in which the most recent change-in-control event occurred already have been issued or made available to be issued, the application of this guidance would be a change in accounting principle. The Company is currently evaluating the impact of this guidance on its consolidated statements of operations and financial position, specifically as it relates to the contemplated Merger with Platinum. Refer to “Note 20. Commitments, Contingencies and Other Items”, for more information with respect to the Merger.
	Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists
	In July 2013, the FASB issued ASU No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (“ASU 2013-11”). The objective of ASU 2013-11 is to improve the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. ASU 2013-11 seeks to reduce the diversity in practice by providing guidance on the presentation of unrecognized tax benefits to better reflect the manner in which an entity would settle at the reporting date any additional income taxes that would result from the disallowance of a tax position when net operating loss carryforwards, similar tax losses, or tax credit carryforwards exist. ASU 2013-11 became effective for annual and interim reporting periods beginning after December 15, 2013. The Company prospectively adopted ASU 2013-11 effective January 1, 2014 and the adoption of this guidance did not have a material impact on the Company’s consolidated statements of operations and financial position.
	Financial Services - Investment Companies (Topic 946) Amendments to the Scope, Measurement, and Disclosure Requirements
	In June 2013, the FASB issued ASU No. 2013-08, Amendments to the Scope, Measurement, and Disclosure Requirements (“ASU 2013-08”). The objective of ASU 2013-08 is to change the approach to the investment company assessment, clarify the characteristics of an investment company and provide comprehensive guidance for assessing whether an entity is an investment company. In addition, ASU 2013-08 will require an investment company to measure noncontrolling ownership interests in other investment companies at fair value rather than using the equity method of accounting and require the following additional disclosures: (a) the fact that the entity is an investment company and is applying the guidance, (b) information about changes, if any, in an entity’s status as an investment company, and (c) information about financial support provided or contractually required to be provided by an investment company to any of its investees. ASU 2013-08 became effective for annual and interim reporting periods beginning after December 15, 2013. The Company prospectively adopted ASU 2013-08 effective January 1, 2014 and the adoption of this guidance did not have a material impact on the Company’s consolidated statements of operations and financial position.
	RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS NOT YET ADOPTED
	Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity
	In April 2014, the FASB issued ASU No. 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity (“ASU 2014-08”). The objective of ASU 2014-08 is to improve the definition of discontinued operations by limiting discontinued operations reporting to disposals of components of an entity that represent strategic shifts that have (or will have) a major effect on an entity’s operations and financial results. ASU 2014-08 will also require expanded disclosures for discontinued operations and require an entity to disclose the pretax profit or loss of an individually significant component of an entity that does not qualify for discontinued operations reporting. ASU 2014-08 is prospectively effective for public business entities in annual periods beginning on or after December 15, 2014, and interim periods beginning on or after December 15, 2015. Entities may early adopt ASU 2014-08 for new disposals that have not been reported in the consolidated financial statements previously issued or available for issuance. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position.
	Revenue from Contracts with Customers
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). ASU 2014-09 provides comprehensive guidance on the recognition of revenue from customers arising from the transfer of goods and services. 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. ASU 2014-09 also provides guidance on accounting for certain contract costs and will also require new disclosures. ASU 2014-09 is effective for public business entities in annual and interim periods beginning after December 15, 2016. Early adoption is permitted. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position.
	Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period
	In June 2014, the FASB Issued ASU No. 2014-12, Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period (“ASU 2014-12”). The objective of ASU 2014-12 is to resolve the diverse accounting treatment of share-based payment awards in situations where an employee would be eligible to vest in the award regardless of whether the employee is rendering service on the date the performance target is achieved. For example, if an employee is eligible to retire or otherwise terminate employment before the end of the period in which a performance target could be achieved and still be eligible to vest in the award. ASU 2014-12 will resolve if and when the performance target is achieved. ASU 2014-12 is effective for all entities in annual and interim periods beginning after December 15, 2014, with early adoption permitted. Entities may apply the amendments in ASU 2014-12 either (a) prospectively to all awards granted or modified after the effective date or (b) retrospectively to all awards with performance targets that are outstanding as of the beginning of the earliest annual period presented in the financial statements and to all new or modified awards thereafter. The Company is currently evaluating the impact of this guidance; however, it is not expected to have a material impact on the Company’s consolidated statements of operations and financial position.

Discontinued_Operations_Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Schedule of Assets, Liabilities, Shareholder's Equity and Details of the Income (Loss) from Discontinued Operations	Details of the income (loss) from discontinued operations for the years ended December 31, 2013 and 2012 are as follows:
		Year ended December 31, 2013	REAL
		Revenues
		Net investment income	$	1,150
		Net foreign exchange gains	849
		Other income	701
		Net realized and unrealized losses on investments	(18		)
		Total revenues	2,682
		Expenses
		Operational expenses	89
		Corporate expenses	104
		Total expenses	193
		Income before taxes	2,489
		Income tax expense	(67		)
		Income from discontinued operations	$	2,422
		Year ended December 31, 2012	REAL			U.S.-based insurance operations			Total
		Revenues
		Net investment income	$	2,517		$	—		$	2,517
		Net foreign exchange losses	(96		)	—			(96		)
		Other (loss) income	(20,785		)	2,730			(18,055		)
		Net realized and unrealized gains on investments	3			—			3
		Total revenues	(18,361		)	2,730			(15,631		)
		Expenses
		Operational expenses	150			436			586
		Corporate expenses	236			—			236
		Total expenses	386			436			822
		(Loss) income before taxes	(18,747		)	2,294			(16,453		)
		Income tax expense	(16		)	(7		)	(23		)
		(Loss) income from discontinued operations	$	(18,763	)	$	2,287		$	(16,476	)

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets and Goodwill	The following table shows an analysis of goodwill and other intangible assets:
			Goodwill and other intangible assets
			Goodwill			Other intangible assets			Total
		Balance as of December 31, 2012
		Gross amount	$	8,160		$	12,999		$	21,159
		Accumulated impairment losses and amortization	(2,299		)	(10,374		)	(12,673		)
			5,861			2,625			8,486
		Amortization	—			(375		)	(375		)
		Balance as of December 31, 2013
		Gross amount	8,160			12,999			21,159
		Accumulated impairment losses and amortization	(2,299		)	(10,749		)	(13,048		)
			5,861			2,250			8,111
		Amortization	—			(209		)	(209		)
		Balance as of December 31, 2014
		Gross amount	8,160			12,999			21,159
		Accumulated impairment losses and amortization	(2,299		)	(10,958		)	(13,257		)
			$	5,861		$	2,041		$	7,902
Schedule of Goodwill and Other Intangible Assets Included In Equity Method Investments	The following table shows an analysis of goodwill and other intangible assets included in investments in other ventures, under equity method:
			Goodwill and other intangible assets included
			in investments in other  ventures, under equity method
			Goodwill			Other intangible  assets			Total
		Balance as of December 31, 2012
		Gross amount	$	10,840		$	44,323		$	55,163
		Accumulated impairment losses and amortization	—			(24,769		)	(24,769		)
			10,840			19,554			30,394
		Acquired during the year	1,705			1,155			2,860
		Amortization	—			(4,042		)	(4,042		)
		Balance as of December 31, 2013
		Gross amount	12,545			45,478			58,023
		Accumulated impairment losses and amortization	—			(28,811		)	(28,811		)
			12,545			16,667			29,212
		Adjustments to gross amount	(227		)	(78		)	(305		)
		Amortization	—			(3,655		)	(3,655		)
		Balance as of December 31, 2014
		Gross amount	12,318			45,400			57,718
		Accumulated impairment losses and amortization	—			(32,466		)	(32,466		)
			$	12,318		$	12,934		$	25,252
Schedule of Other Intangible Assets By Major Class	The gross carrying value and accumulated amortization by major category of other intangible assets is shown below:
			Other intangible assets
		At December 31, 2014	Gross			Accumulated			Total
			carrying			amortization and impairment losses
			value
		Customer relationships and customer lists	$	40,562		$	(28,057	)	$	12,505
		Lloyd’s managing agency license	1,867			—			1,867
		Trademarks and trade names	610			(159		)	451
		Covenants not-to-compete	2,130			(1,978		)	152
		Software	8,730			(8,730		)	—
		Patents and intellectual property	4,500			(4,500		)	—
			$	58,399		$	(43,424	)	$	14,975
			Other intangible assets
		At December 31, 2013	Gross			Accumulated			Total
			carrying			amortization and impairment losses
			value
		Customer relationships and customer lists	$	40,640		$	(24,522	)	$	16,118
		Lloyd’s managing agency license	1,867			—			1,867
		Covenants not-to-compete	2,130			(1,674		)	456
		Trademarks and trade names	610			(134		)	476
		Software	8,730			(8,730		)	—
		Patents and intellectual property	4,500			(4,500		)	—
			$	58,477		$	(39,560	)	$	18,917
Schedule of Expected Amortization Expense	Expected amortization of the other intangible assets, including other intangible assets recorded in investments in other ventures, under equity method, is shown below:
			Other			Other			Total
			intangibles			intangible
						assets
						included
						in investments
						in other
						ventures, under
						equity method
		2015	$	174		$	2,991		$	3,165
		2016	—			2,292			2,292
		2017	—			1,914			1,914
		2018	—			1,484			1,484
		2019	—			1,041			1,041
		2020 and thereafter	—			3,212			3,212
		Total remaining amortization expense	$	174		$	12,934		$	13,108
		Indefinite lived	1,867			—			1,867
		Total	$	2,041		$	12,934		$	14,975

Investments_Tables

Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Investments [Abstract]
Schedule of Fair Value of Fixed Maturity Investments Trading	The following table summarizes the fair value of fixed maturity investments trading:
			December 31,			December 31,
			2014			2013
		U.S. treasuries	$	1,671,471		$	1,352,413
		Agencies	96,208			186,050
		Non-U.S. government (Sovereign debt)	280,651			334,580
		Non-U.S. government-backed corporate	146,467			237,479
		Corporate	1,610,442			1,803,415
		Agency mortgage-backed	312,333			336,661
		Non-agency mortgage-backed	241,590			243,795
		Commercial mortgage-backed	373,117			303,214
		Asset-backed	24,406			11,429
		Total fixed maturity investments trading	$	4,756,685		$	4,809,036
Schedule of Fair Value of Fixed Maturity Investments Available For Sale	The following table summarizes the amortized cost, fair value and related unrealized gains and losses and non-credit other-than-temporary impairments of fixed maturity investments available for sale:
						Included in Accumulated
						Other Comprehensive Income
		At December 31, 2014	Amortized			Gross				Gross				Fair Value				Non-Credit
			Cost			Unrealized				Unrealized								Other-Than-
						Gains				Losses								Temporary
																		Impairments
																		(1)
		Agency mortgage-backed	$	3,928		$	359			$	—			$	4,287			$	—
		Non-agency mortgage-backed	9,478			1,985				(3		)		11,460				656
		Commercial mortgage-backed	7,291			643				—				7,934				—
		Asset-backed	3,075			129				—				3,204				—
		Total fixed maturity investments available for sale	$	23,772		$	3,116			$	(3	)		$	26,885			$	656
						Included in Accumulated
						Other Comprehensive Income
		At December 31, 2013	Amortized Cost			Gross				Gross				Fair Value				Non-Credit
						Unrealized				Unrealized								Other-Than-
						Gains				Losses								Temporary
																		Impairments
																		(1)
		Agency mortgage-backed	$	4,880		$	378			$	(11	)		$	5,247			$	—
		Non-agency mortgage-backed	11,735			2,414				(6		)		14,143				(742		)
		Commercial mortgage-backed	10,052			970				—				11,022				—
		Asset-backed	3,606			223				—				3,829				—
		Total fixed maturity investments available for sale	$	30,273		$	3,985			$	(17	)		$	34,241			$	(742	)
	-1	Represents the non-credit component of other-than-temporary impairments recognized in accumulated other comprehensive income adjusted for subsequent sales of securities. It does not include the change in fair value subsequent to the impairment measurement date.
Schedule of Contractual Maturities of Fixed Maturity Investments	Contractual maturities of fixed maturity investments are described in the following table. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
			Trading							Available for Sale								Total Fixed Maturity Investments
		At December 31, 2014	Amortized			Fair Value				Amortized Cost				Fair Value				Amortized Cost				Fair Value
			Cost
		Due in less than one year	$	153,250		$	151,803			$	—			$	—			$	153,250			$	151,803
		Due after one through five years	2,976,602			2,969,828				—				—				2,976,602				2,969,828
		Due after five through ten years	544,285			537,636				—				—				544,285				537,636
		Due after ten years	140,294			145,972				—				—				140,294				145,972
		Mortgage-backed	910,897			927,040				20,697				23,681				931,594				950,721
		Asset-backed	24,285			24,406				3,075				3,204				27,360				27,610
		Total	$	4,749,613		$	4,756,685			$	23,772			$	26,885			$	4,773,385			$	4,783,570
Schedule of Fair Value of Equity Investments Trading	The following table summarizes the fair value of equity investments trading:
			December 31,			December 31,
			2014			2013
		Financials	$	222,190		$	152,905
		Communications and technology	31,376			4,300
		Industrial, utilities and energy	28,859			25,350
		Consumer	19,522			44,115
		Healthcare	16,582			15,340
		Basic materials	3,569			12,766
		Total	$	322,098		$	254,776
Schedule of Net Investment Income	The components of net investment income are as follows:
		Year ended December 31,	2014			2013				2012
		Fixed maturity investments	$	100,855		$	95,907			$	103,330
		Short term investments	944			1,698				1,007
		Equity investments	3,450			2,295				1,086
		Other investments
		Hedge funds and private equity investments	18,867			45,810				36,635
		Other	11,144			73,692				35,196
		Cash and cash equivalents	395			191				277
			135,655			219,593				177,531
		Investment expenses	(11,339		)	(11,565		)		(11,806		)
		Net investment income	$	124,316		$	208,028			$	165,725
Schedule of Net Realized and Unrealized Gains On Investments and Net Other-Than-Temporary Impairments	Net realized and unrealized gains on investments and net other-than-temporary impairments are as follows:
		Year ended December 31,	2014			2013				2012
		Gross realized gains	$	45,568		$	72,492			$	97,787
		Gross realized losses	(14,868		)	(50,206		)		(16,705		)
		Net realized gains on fixed maturity investments	30,700			22,286				81,082
		Net unrealized gains (losses) on fixed maturity investments trading	19,680			(87,827		)		75,279
		Net realized and unrealized (losses) gains on investments-related derivatives	(30,931		)	31,058				(866		)
		Net realized gains on equity investments trading	10,908			26,650				—
		Net unrealized gains on equity investments trading	11,076			42,909				7,626
		Net realized and unrealized gains on investments	$	41,433		$	35,076			$	163,121
		Total other-than-temporary impairments	$	—		$	—			$	(395	)
		Portion recognized in other comprehensive income, before taxes	—			—				52
		Net other-than-temporary impairments	$	—		$	—			$	(343	)
Schedule of Reclassification out of Accumulated Other Comprehensive Income	The following table provides an analysis of the components of other comprehensive income and reclassifications out of accumulated other comprehensive income.
			Year ended December 31, 2014
			Investments in other ventures			Fixed maturity investments available for sale				Total
		Beginning balance	$	163		$	3,968			$	4,131
		Other comprehensive income (loss) before reclassifications	140			(855		)		(715		)
		Amounts reclassified from accumulated other comprehensive income by statement of operations line item:
		Realized gains reclassified from accumulated other comprehensive income to net realized and unrealized gains (losses) on investments	—			—				—
		Net current-period other comprehensive income (loss)	140			(855		)		(715		)
		Ending balance	$	303		$	3,113			$	3,416
			Year ended December 31, 2013
			Investments in other ventures			Fixed maturity investments available for sale				Total
		Beginning balance	$	1,625		$	11,997			$	13,622
		Other comprehensive loss before reclassifications	(1,462		)	(481		)		(1,943		)
		Amounts reclassified from accumulated other comprehensive income by statement of operations line item:
		Realized gains reclassified from accumulated other comprehensive income to net realized and unrealized gains (losses) on investments	—			(7,548		)		(7,548		)
		Net current-period other comprehensive loss	(1,462		)	(8,029		)		(9,491		)
		Ending balance	$	163		$	3,968			$	4,131
Schedule of Fixed Maturity Investments Available For Sale In Continual Unrealized Loss Position	The following tables provide an analysis of the length of time the Company’s fixed maturity investments available for sale in an unrealized loss have been in a continual unrealized loss position.
			Less than 12 Months							12 Months or Greater								Total
		At December 31, 2014	Fair Value			Unrealized				Fair Value				Unrealized				Fair Value				Unrealized
						Losses								Losses								Losses
		Non-agency mortgage-backed	$	—		$	—			$	69			$	(3	)		$	69			$	(3	)
		Total	$	—		$	—			$	69			$	(3	)		$	69			$	(3	)
			Less than 12 Months							12 Months or Greater								Total
		At December 31, 2013	Fair Value			Unrealized				Fair Value				Unrealized				Fair Value				Unrealized
						Losses								Losses								Losses
		Agency mortgage-backed	$	726		$	(11	)		$	—			$	—			$	726			$	(11	)
		Non-agency mortgage-backed	—			—				89				(6		)		89				(6		)
		Commercial mortgage-backed	39			—				—				—				39				—
		Total	$	765		$	(11	)		$	89			$	(6	)		$	854			$	(17	)
Rollforward of the Amount of Other-Than-Temporary Impairments Related To Credit Losses Recognized in Earnings For Which A Portion Of An Other-Than-Temporary Impairment Was Recognized In Accumulated Other Comprehensive Income	The following table provides a rollforward of the amount of other-than-temporary impairments related to credit losses recognized in earnings for which a portion of an other-than-temporary impairment was recognized in accumulated other comprehensive income:
			2014			2013
		Balance – January 1	$	561		$	838
		Additions:
		Amount related to credit loss for which an other-than-temporary impairment was not previously recognized	—			—
		Amount related to credit loss for which an other-than-temporary impairment was previously recognized	—			—
		Reductions:
		Securities sold during the period	(63		)	(277		)
		Securities for which the amount previously recognized in other comprehensive income was recognized in earnings, because the Company intends to sell the security or is more likely than not the Company will be required to sell the security	—			—
		Increases in cash flows expected to be collected that are recognized over the remaining life of the security	—			—
		Balance – December 31	$	498		$	561
Schedule of Other Investments	The table below shows the fair value of the Company’s portfolio of other investments:
		At December 31,	2014			2013
		Private equity partnerships	$	281,932		$	322,391
		Catastrophe bonds	200,329			229,016
		Senior secured bank loan funds	19,316			18,048
		Hedge funds	2,570			3,809
		Total other investments	$	504,147		$	573,264
Schedule of Equity Method Investments	The table below shows the Company’s portfolio of investments in other ventures, under equity method:
			2014										2013
		At December 31,	Investment			Ownership %			Carrying  Value				Investment				Ownership %			Carrying  Value
		THIG	$	50,000		25	%		$	20,811			$	50,000			25	%		$	25,107
		Tower Hill	10,000			30.3	%		18,991				10,000				29.4	%		14,506
		Tower Hill Re	4,250			25	%		5,162				—				—	%		—
		Tower Hill Signature	500			25	%		5,692				500				25	%		2,515
		Total Tower Hill Companies	64,750						50,656				60,500							42,128
		Top Layer Re	65,375			50	%		60,911				65,375				50	%		50,500
		Angus	10,507			40.4	%		8,072				10,507				42.5	%		9,180
		Other	3,000			22	%		1,074				3,000				22	%		3,808
		Total investments in other ventures, under equity method	$	143,632					$	120,713			$	139,382						$	105,616
Schedule of Equity In Earnings (Losses) of Equity Method Investments	The table below shows the Company’s equity in earnings of other ventures, under equity method:
		Year ended December 31,	2014			2013				2012
		Tower Hill Companies	$	18,376		$	10,270			$	4,965
		Top Layer Re	10,411			13,836				20,792
		Angus	(1,402		)	(858		)		(2,519		)
		Other	(1,310		)	(54		)		—
		Total equity in earnings of other ventures	$	26,075		$	23,194			$	23,238

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Schedule Of Assets And Liabilities Measured At Fair Value On A Recurring Basis	Below is a summary of the assets and liabilities that are measured at fair value on a recurring basis and also represents the carrying amount on the Company’s consolidated balance sheets:
		At December 31, 2014	Total			Quoted			Significant			Significant
						Prices in Active			Other			Unobservable
						Markets for			Observable			Inputs
						Identical			Inputs			(Level 3)
						Assets			(Level 2)
						(Level 1)
		Fixed maturity investments
		U.S. treasuries	$	1,671,471		$	1,671,471		$	—		$	—
		Agencies	96,208			—			96,208			—
		Non-U.S. government (Sovereign debt)	280,651			—			280,651			—
		Non-U.S. government-backed corporate	146,467			—			146,467			—
		Corporate	1,610,442			—			1,594,782			15,660
		Agency mortgage-backed	316,620			—			316,620			—
		Non-agency mortgage-backed	253,050			—			253,050			—
		Commercial mortgage-backed	381,051			—			381,051			—
		Asset-backed	27,610			—			27,610			—
		Total fixed maturity investments	4,783,570			1,671,471			3,096,439			15,660
		Short term investments	1,013,222			—			1,013,222			—
		Equity investments trading	322,098			322,098			—			—
		Other investments
		Private equity partnerships	281,932			—			—			281,932
		Catastrophe bonds	200,329			—			200,329			—
		Senior secured bank loan fund	19,316			—			—			19,316
		Hedge funds	2,570			—			—			2,570
		Total other investments	504,147			—			200,329			303,818
		Other assets and (liabilities)
		Assumed and ceded (re)insurance contracts	(8,744		)	—			—			(8,744		)
		Derivatives (1)	6,345			(569		)	7,104			(190		)
		Other	(11,509		)	—			(11,509		)	—
		Total other assets and (liabilities)	(13,908		)	(569		)	(4,405		)	(8,934		)
			$	6,609,129		$	1,993,000		$	4,305,585		$	310,544
	-1	See “Note 19. Derivative Instruments” for additional information related to the fair value by type of contract, of derivatives entered into by the Company.
		At December 31, 2013	Total			Quoted			Significant			Significant
						Prices in Active			Other			Unobservable
						Markets for			Observable			Inputs
						Identical			Inputs			(Level 3)
						Assets			(Level 2)
						(Level 1)
		Fixed maturity investments
		U.S. treasuries	$	1,352,413		$	1,352,413		$	—		$	—
		Agencies	186,050			—			186,050			—
		Non-U.S. government (Sovereign debt)	334,580			—			334,580			—
		Non-U.S. government-backed corporate	237,479			—			237,479			—
		Corporate	1,803,415			—			1,775,835			27,580
		Agency mortgage-backed	341,908			—			341,908			—
		Non-agency mortgage-backed	257,938			—			257,938			—
		Commercial mortgage-backed	314,236			—			314,236			—
		Asset-backed	15,258			—			15,258			—
		Total fixed maturity investments	4,843,277			1,352,413			3,463,284			27,580
		Short term investments	1,044,779			—			1,044,779			—
		Equity investments trading	254,776			254,776			—			—
		Other investments
		Private equity partnerships	322,391			—			—			322,391
		Catastrophe bonds	229,016			—			229,016			—
		Senior secured bank loan funds	18,048			—			—			18,048
		Hedge funds	3,809			—			—			3,809
		Total other investments	573,264			—			229,016			344,248
		Other assets and (liabilities)
		Derivatives (1)	4,758			823			6,425			(2,490		)
		Other	(12,991		)	—			(12,991		)	—
		Total other assets and (liabilities)	(8,233		)	823			(6,566		)	(2,490		)
			$	6,707,863		$	1,608,012		$	4,730,513		$	369,338
	(1) See “Note 19. Derivative Instruments” for additional information related to the fair value by type of contract, of derivatives entered into by the Company.
Schedule Of Quantitative Information Used As Level 3 Inputs	Below is a summary of quantitative information regarding the significant observable and unobservable inputs (Level 3) used in determining the fair value of assets and liabilities measured at fair value on a recurring basis:
		December 31, 2014	Fair Value			Valuation Technique		Unobservable (U)	Low			High			Weighted Average or Actual
			(Level 3)					and Observable (O)
								Inputs
		Fixed maturity investments
		Corporate	$	15,660		Discounted cash flow (“DCF”)		Credit spread (U)	n/a			n/a			0.8		%
								Liquidity discount (U)	n/a			n/a			1		%
								Risk-free rate (O)	n/a			n/a			0.5		%
								Dividend rate (O)	n/a			n/a			6.5		%
		Total fixed maturity investments	15,660
		Other investments
		Private equity partnerships	281,932			Net asset valuation		Estimated performance (U)	(42.1		)%	17		%	0.1		%
		Senior secured bank loan fund	19,316			Net asset valuation		Estimated performance (U)	n/a			n/a			0.8		%
		Hedge funds	2,570			Net asset valuation		Estimated performance (U)	0		%	0		%	0		%
		Total other investments	303,818
		Other assets and (liabilities)
		Assumed and ceded (re)insurance contracts	(8,744		)	Internal valuation model		Net undiscounted cash flows (U)	$	160		$	8,006		$	2,528
								Contract period (O)	549			1,100			832
								Discount rate (U)	n/a			n/a			1.1		%
		Weather contract	(190		)	Internal valuation model		See below	n/a			n/a			See below
		Total other assets and (liabilities)	(8,934		)
			$	310,544
Schedule Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Level 3 Inputs	Below is a reconciliation of the beginning and ending balances, for the periods shown, of assets and liabilities measured at fair value on a recurring basis using Level 3 inputs. Interest and dividend income are included in net investment income and are excluded from the reconciliation.
			Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
			Fixed maturity			Other			Other assets  and (liabilities)			Total
			investments			investments
			trading
		Balance - January 1, 2013	$	27,792		$	381,067		$	21,513		$	430,372
		Total unrealized gains (losses)
		Included in net investment income	2,288			80,113			(1,331		)	81,070
		Included in other loss	—			—			(625		)	(625		)
		Total realized (losses) gains
		Included in net investment income	—			(4,114		)	—			(4,114		)
		Included in other loss	—			—			(2,083		)	(2,083		)
		Total foreign exchange losses	—			1,352			—			1,352
		Purchases	—			48,287			(1,722		)	46,565
		Settlements	(2,500		)	(95,144		)	—			(97,644		)
		Reclassified from other assets to other investments	—			18,242			(18,242		)	—
		Net transfers out of Level 3	—			(85,555		)	—			(85,555		)
		Balance - December 31, 2013	$	27,580		$	344,248		$	(2,490	)	$	369,338
		Change in unrealized gains for the period included in earnings for assets held at the end of the period included in net investment income	$	2,288		$	78,903		$	(1,331	)	$	79,860
			Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
			Fixed maturity			Other			Other assets			Total
			investments trading			investments			and
									(liabilities)
		Balance - January 1, 2014	$	27,580		$	344,248		$	(2,490	)	$	369,338
		Total unrealized gains (losses)
		Included in net investment income	12,724			1,045			1,455			15,224
		Total realized losses
		Included in other loss	—			—			1,262			1,262
		Total foreign exchange gains	—			(3,279		)	(21		)	(3,300		)
		Purchases	—			43,130			(9,140		)	33,990
		Settlements	—			(81,326		)	—			(81,326		)
		Net transfers out of Level 3	(24,644		)	—			—			(24,644		)
		Balance - December 31, 2014	$	15,660		$	303,818		$	(8,934	)	$	310,544
		Change in unrealized gains for the period included in earnings for assets held at the end of the period included in net investment income	$	(66	)	$	1,045		$	1,455		$	2,434
Schedule Of The Balances The Company Has Elected To Account For At Fair Value	Below is a summary of the balances the Company has elected to account for at fair value:
			2014			2013
		Other investments	$	504,147		$	573,264
		Other assets (liabilities)	$	(8,744	)	$	—
Schedule Of Other Investments Measured Using Net Asset Valuations	The table below shows the Company’s portfolio of other investments measured using net asset valuations:
		At December 31, 2014	Fair Value			Unfunded			Redemption Frequency		Redemption	Redemption
						Commitments					Notice Period (Minimum Days)	Notice Period (Maximum Days)
		Private equity partnerships	$	281,932		$	77,712		See below		See below	See below
		Senior secured bank loan fund	19,316			6,301			See below		See below	See below
		Hedge funds	2,570			—			See below		See below	See below
		Total other investments measured using net asset valuations	$	303,818		$	84,013

Reinsurance_Tables

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2014
Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Abstract]
Effect Of Reinsurance And Retrocessional Activity On Premiums Written And Earned And On Net Claims And Claim Expenses Incurred	The following table sets forth the effect of reinsurance and retrocessional activity on premiums written and earned and on net claims and claim expenses incurred:
		Year ended December 31,	2014			2013			2012
		Premiums written
		Direct	$	76,511		$	54,334		$	36,367
		Assumed	1,474,061			1,551,078			1,515,224
		Ceded	(482,336		)	(401,465		)	(448,934		)
		Net premiums written	$	1,068,236		$	1,203,947		$	1,102,657
		Premiums earned
		Direct	$	66,027		$	44,530		$	34,028
		Assumed	1,450,047			1,482,511			1,465,701
		Ceded	(453,658		)	(412,415		)	(430,374		)
		Net premiums earned	$	1,062,416		$	1,114,626		$	1,069,355
		Claims and claim expenses
		Gross claims and claim expenses incurred	$	228,581		$	185,139		$	403,491
		Claims and claim expenses recovered	(30,634		)	(13,852		)	(78,280		)
		Net claims and claim expenses incurred	$	197,947		$	171,287		$	325,211

Reserve_for_Claims_and_Claim_E1

Reserve for Claims and Claim Expenses (Tables)	12 Months Ended
	Dec. 31, 2014
Insurance Loss Reserves [Abstract]
Schedule of Liability for Unpaid Claims and Claim Expenses	Activity in the liability for unpaid claims and claim expenses is summarized as follows:
		Year ended December 31,	2014			2013			2012
		Net reserves as of January 1	$	1,462,705		$	1,686,865		$	1,588,325
		Net incurred related to:
		Current year	341,745			315,241			483,180
		Prior years	(143,798		)	(143,954		)	(157,969		)
		Total net incurred	197,947			171,287			325,211
		Net paid related to:
		Current year	39,830			32,212			84,056
		Prior years	275,006			363,235			142,615
		Total net paid	314,836			395,447			226,671
		Net reserves as of December 31	1,345,816			1,462,705			1,686,865
		Reinsurance recoverable as of December 31	66,694			101,025			192,512
		Gross reserves as of December 31	$	1,412,510		$	1,563,730		$	1,879,377
Schedule of Prior Year Development of Liability for Unpaid Claims and Claim Expenses by Segment	The following table details the Company’s prior year development by segment of its liability for unpaid claims and claim expenses:
		Year ended December 31,	2014			2013			2012
		Catastrophe Reinsurance	$	(65,511	)	$	(102,037	)	$	(110,568	)
		Specialty Reinsurance	(55,909		)	(34,111		)	(34,146		)
		Lloyd’s	(16,241		)	(8,256		)	(16,202		)
		Other	(6,137		)	450			2,947
		Total favorable development of prior accident years net claims and claim expenses	$	(143,798	)	$	(143,954	)	$	(157,969	)
Schedule of Details of Development of Liability for Unpaid Claims and Claim Expenses by Segment	The following table details the development of the Company’s liability for unpaid claims and claim expenses for each of its Catastrophe Reinsurance, Specialty Reinsurance and Lloyd’s segments and Other category, for the year ended December 31, 2013 split between catastrophe net claims and claim expenses and attritional net claims and claim expenses:
		Year ended December 31, 2013	Catastrophe Reinsurance Segment			Specialty Reinsurance Segment			Lloyd's Segment			Other			Total
		Catastrophe net claims and claim expenses
		Large catastrophe events
		Storm Sandy (2012)	$	(44,460	)	$	—		$	(3,825	)	$	—		$	(48,285	)
		Tohoku Earthquake and Tsunami (2011)	(18,033		)	(1,000		)	—			—			(19,033		)
		Hurricanes Gustav and Ike (2008)	(16,261		)	—			—			(404		)	(16,665		)
		New Zealand Earthquake (2011)	(10,944		)	—			—			—			(10,944		)
		Windstorm Kyrill (2007)	(8,244		)	—			—			—			(8,244		)
		Hurricane Isaac (2012)	2,610			—			—			—			2,610
		New Zealand Earthquake (2010)	11,040			300			—			—			11,340
		Other	(776		)	(1,763		)	(1,442		)	(1,325		)	(5,306		)
		Total large catastrophe events	(85,068		)	(2,463		)	(5,267		)	(1,729		)	(94,527		)
		Small catastrophe events
		U.S. PCS 83 Wind and Thunderstorm (2012)	(3,500		)	—			—			—			(3,500		)
		U.S. PCS 76 Wind and Thunderstorm (2012)	(300		)	—			—			—			(300		)
		U.S. PCS 70 Wind and Thunderstorm (2012)	8,225			—			—			—			8,225
		Other	(21,394		)	—			—			—			(21,394		)
		Total small catastrophe events	(16,969		)	—			—			—			(16,969		)
		Total catastrophe net claims and claim expenses	$	(102,037	)	$	(2,463	)	$	(5,267	)	$	(1,729	)	$	(111,496	)
		Attritional net claims and claim expenses
		Bornhuetter-Ferguson actuarial method - actual reported claims less than expected claims	$	—		$	(21,216	)	$	(3,263	)	$	2,179		$	(22,300	)
		Actuarial assumption changes	—			(10,432		)	274			—			(10,158		)
		Total attritional net claims and claim expenses	$	—		$	(31,648	)	$	(2,989	)	$	2,179		$	(32,458	)
		Total favorable development of prior accident years net claims and claim expenses	$	(102,037	)	$	(34,111	)	$	(8,256	)	$	450		$	(143,954	)
	Specialty Reinsurance and Lloyd’s segments and Other category, for the year ended December 31, 2014 split between catastrophe net claims and claim expenses and attritional net claims and claim expenses:
		Year ended December 31, 2014	Catastrophe Reinsurance Segment			Specialty Reinsurance Segment			Lloyd's Segment			Other			Total
		Catastrophe net claims and claim expenses
		Large catastrophe events
		Storm Sandy (2012)	$	(20,104	)	$	—		$	(4,128	)	$	—		$	(24,232	)
		April and May U.S. Tornadoes (2011)	(13,939		)	—			—			—			(13,939		)
		Thailand Floods (2011)	(9,254		)	(2,500		)	—			—			(11,754		)
		LIBOR (2011 and 2012)	—			(10,500		)	(1,250		)	—			(11,750		)
		Hurricanes Gustav and Ike (2008)	(6,647		)	—			—			—			(6,647		)
		Tohoku Earthquake and Tsunami (2011)	(3,489		)	(1,642		)	—			—			(5,131		)
		Hurricane Irene (2011)	(4,506		)	—			—			—			(4,506		)
		Windstorm Kyrill (2007)	(3,615		)	—			—			—			(3,615		)
		Subprime (2007)	—			5,049			—			—			5,049
		New Zealand Earthquake (2010)	24,692			—			—			—			24,692
		Other	(10,644		)	(1,826		)	(1,234		)	—			(13,704		)
		Total large catastrophe events	(47,506		)	(11,419		)	(6,612		)	—			(65,537		)
		Small catastrophe events
		European Floods (2013)	(7,552		)	—			—			—			(7,552		)
		U.S. PCS 24 Wind and Thunderstorm (2013)	(6,712		)	—			—			—			(6,712		)
		U.S. PCS 70 and 73 Wind and Thunderstorm (2012)	13,362			—			—			—			13,362
		Other	(17,103		)	—			(2,687		)	(6,137		)	(25,927		)
		Total small catastrophe events	(18,005		)	—			(2,687		)	(6,137		)	(26,829		)
		Total catastrophe net claims and claim expenses	$	(65,511	)	$	(11,419	)	$	(9,299	)	$	(6,137	)	$	(92,366	)
		Attritional net claims and claim expenses
		Bornhuetter-Ferguson actuarial method - actual reported claims less than expected claims	$	—		$	(44,490	)	$	(6,942	)	$	—		$	(51,432	)
		Total attritional net claims and claim expenses	$	—		$	(44,490	)	$	(6,942	)	$	—		$	(51,432	)
		Total favorable development of prior accident years net claims and claim expenses	$	(65,511	)	$	(55,909	)	$	(16,241	)	$	(6,137	)	$	(143,798	)
	The following table details the development of the Company’s liability for unpaid claims and claim expenses for each of its Catastrophe Reinsurance, Specialty Reinsurance and Lloyd’s segments and Other category, for the year ended December 31, 2012 split between catastrophe net claims and claim expenses and attritional net claims and claim expenses:
		Year ended December 31, 2012	Catastrophe Reinsurance Segment			Specialty Reinsurance Segment			Lloyd’s Segment			Other			Total
		Catastrophe net claims and claim expenses
		Large catastrophe events
		Chile Earthquake (2010)	$	(24,575	)	$	—		$	—		$	—		$	(24,575	)
		Hurricanes Gustav and Ike (2008)	(17,541		)	—			—			(2,926		)	(20,467		)
		U.K. Floods (2007)	(17,271		)	—			—			—			(17,271		)
		Hurricanes Katrina, Rita and Wilma (2005)	(6,420		)	(3,000		)	—			1,690			(7,730		)
		Hurricane Irene (2011)	(4,630		)	—			(2,500		)	—			(7,130		)
		Thailand Floods (2011)	(3,933		)	—			(5,500		)	—			(9,433		)
		Tohoku Earthquake and Tsunami (2011)	(3,896		)	—			—			—			(3,896		)
		Windstorm Kyrill (2007)	(3,417		)	—			—			—			(3,417		)
	New Zealand Earthquake (2010)	3,570			—			—			—			3,570
	New Zealand Earthquake (2011)	17,912			—			—			—			17,912
	Other	(2,542		)	—			(1,476		)	65			(3,953		)
	Total large catastrophe events	(62,743		)	(3,000		)	(9,476		)	(1,171		)	(76,390		)
	Small catastrophe events
	Danish Floods (2011)	(5,000		)	—			—			—			(5,000		)
	U.S. PCS 63 Winter Storm (2011)	(5,000		)	—			—			—			(5,000		)
	U.S. PCS 42 Winter Storm (2011)	(2,560		)	—			—			—			(2,560		)
	U.S. PCS 53 Winter Storm (2011)	(2,558		)	—			—			—			(2,558		)
	Other	(32,707		)	—			—			—			(32,707		)
	Total small catastrophe events	(47,825		)	—			—			—			(47,825		)
	Total catastrophe net claims and claim expenses	$	(110,568	)	$	(3,000	)	$	(9,476	)	$	(1,171	)	$	(124,215	)
	Attritional net claims and claim expenses
	Bornhuetter-Ferguson actuarial method - actual reported claims less than expected claims	$	—		$	(16,747	)	$	(8,011	)	$	4,118		$	(20,640	)
	Actuarial assumption changes	—			(14,399		)	1,285			—			(13,114		)
	Total attritional net claims and claim expenses	$	—		$	(31,146	)	$	(6,726	)	$	4,118		$	(33,754	)
	Total favorable development of prior accident years net claims and claim expenses	$	(110,568	)	$	(34,146	)	$	(16,202	)	$	2,947		$	(157,969	)

Debt_and_Credit_Facilities_Tab

Debt and Credit Facilities (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Schedule of Aggregate Amount of Maturities Related to the Company's Debt Obligations	The following table sets forth the scheduled maturity of the Company’s aggregate amount of its debt obligation reflected on its consolidated balance sheet at December 31, 2014:
		2015	$	—
		2016	—
		2017	—
		2018	—
		2019	—
		After 2019	250,000
		Unamortized debt issuance expenses	(478		)
			$	249,522

Noncontrolling_Interests_Table

Noncontrolling Interests (Tables)	12 Months Ended
	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Schedule Of Noncontrolling Interest	The activity in noncontrolling interest is detailed in the table below:
			2014			2013
		Balance – January 1	$	—		$	3,991
		Adjustment of ownership interest	—			(3,709		)
		Net loss attributable to noncontrolling interest	—			(54		)
		Dividends on common shares	—			(228		)
		Balance – December 31	$	—		$	—
	A summary of the Company’s noncontrolling interests on its consolidated balance sheets is set forth below:
			2014			2013
		Redeemable noncontrolling interest - DaVinciRe	$	1,037,306		$	1,063,368
		Redeemable noncontrolling interest - Medici	94,402			36,492
		Redeemable noncontrolling interest	$	1,131,708		$	1,099,860
		Noncontrolling interest - Angus Fund	$	—		$	—
	A summary of the Company’s noncontrolling interests on its consolidated statements of operations is set forth below:
			2014			2013			2012
		Redeemable noncontrolling interest - DaVinciRe	$	149,817		$	150,581		$	147,499
		Redeemable noncontrolling interest - Medici	3,721			617			—
		Noncontrolling interest - Angus Fund	—			(54		)	541
		Net income (loss) attributable to noncontrolling interests	$	153,538		$	151,144		$	148,040
DaVinciRe
Noncontrolling Interest [Line Items]
Schedule Of Redeemable Noncontrolling Interest	The activity in redeemable noncontrolling interest – DaVinciRe is detailed in the table below:
			2014			2013
		Balance – January 1	$	1,063,368		$	968,259
		Redemption of shares from redeemable noncontrolling interest	(224,455		)	(209,356		)
		Sale of shares to redeemable noncontrolling interest	48,576			153,884
		Comprehensive income:
		Net income attributable to redeemable noncontrolling interest	149,817			150,581
		Balance – December 31	$	1,037,306		$	1,063,368
Medici
Noncontrolling Interest [Line Items]
Schedule Of Redeemable Noncontrolling Interest	The activity in redeemable noncontrolling interest – Medici is detailed in the table below:
			2014			2013
		Balance – January 1	$	36,492		$	—
		Redemption of shares from redeemable noncontrolling interest	(3,075		)	(1,325		)
		Sale of shares to redeemable noncontrolling interest	57,264			37,200
		Net income attributable to redeemable noncontrolling interest	3,721			617
		Balance – December 31	$	94,402		$	36,492

Shareholders_Equity_Tables

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Rollforward of Common Stock Issued and Outstanding	The following table is a summary of changes in common shares issued and outstanding:
		Year ended December 31,	2014		2013		2012
		(thousands of shares)
		Issued and outstanding shares – January 1	43,646		45,542		51,543
		Repurchase of shares	(5,355	)	(2,451	)	(6,399	)
		Exercise of options and issuance of restricted stock awards	151		555		398
		Issued and outstanding shares – December 31	38,442		43,646		45,542

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Schedule Of Computation Of Basic And Diluted Earnings Per Common Share	The following table sets forth the computation of basic and diluted earnings per common share:
		Year ended December 31,	2014			2013			2012
		(thousands of shares)
		Numerator:
		Net income available to RenaissanceRe common shareholders	$	510,337		$	665,676		$	566,014
		Amount allocated to participating common shareholders (1)	(6,760		)	(9,520		)	(8,973		)
		Net income allocated to RenaissanceRe common shareholders	$	503,577		$	656,156		$	557,041
		Denominator:
		Denominator for basic income per RenaissanceRe common share - weighted average common shares	39,425			43,349			48,873
		Per common share equivalents of employee stock options and restricted shares	543			779			730
		Denominator for diluted income per RenaissanceRe common share - adjusted weighted average common shares and assumed conversions	39,968			44,128			49,603
		Basic income per RenaissanceRe common share	$	12.77		$	15.14		$	11.4
		Diluted income per RenaissanceRe common share	$	12.6		$	14.87		$	11.23
	-1	Represents earnings attributable to holders of unvested restricted shares issued under the Company’s 2001 Stock Incentive Plan and the Non-Employee Director Stock Incentive Plan.

Taxation_Tables

Taxation (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	The following is a summary of the Company’s income from continuing operations before taxes allocated between domestic and foreign operations:
		Year ended December 31,	2014			2013			2012
		Domestic
		Bermuda	$	701,476		$	873,103		$	795,378
		Foreign
		United Kingdom	(3,166		)	(12,678		)	(15,404		)
		U.S.	(10,977		)	(20,019		)	(16,467		)
		Ireland	1,549			1,855			3,318
		Singapore	(2,018		)	(1,223		)	13
		Income from continuing operations before taxes	$	686,864		$	841,038		$	766,838
Schedule of Components of Income Tax (Expense) Benefit	Income tax (expense) benefit is comprised as follows:
		Year ended December 31, 2014	Current			Deferred			Total
		Total income tax (expense) benefit	$	(699	)	$	91		$	(608	)
		Year ended December 31, 2013
		Total income tax (expense) benefit	$	(2,005	)	$	313		$	(1,692	)
		Year ended December 31, 2012
		Total income tax (expense) benefit	$	(1,667	)	$	254		$	(1,413	)
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the difference between the provision for income taxes and the expected tax provision at the weighted average tax rate is as follows:
		Year ended December 31,	2014			2013			2012
		Expected income tax benefit	$	4,725		$	9,930		$	8,889
		Change in valuation allowance	(5,554		)	(8,574		)	(6,212		)
		Other	221			(3,048		)	(4,090		)
		Income tax expense	$	(608	)	$	(1,692	)	$	(1,413	)
Schedule of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities are presented below:
		At December 31,	2014			2013
		Deferred tax assets
		Tax loss and credit carryforwards	$	37,933		$	34,429
		Deferred interest expense	17,066			12,608
		Accrued expenses	3,413			1,096
		Amortization and depreciation	1,686			1,730
		Deferred underwriting results	1,586			1,873
		Investments	290			4,694
			61,974			56,430
		Deferred tax liabilities
		Amortization and depreciation	(54		)	(155		)
			(54		)	(155		)
		Net deferred tax asset before valuation allowance	61,920			56,275
		Valuation allowance	(61,660		)	(56,106		)
		Net deferred tax asset (liability)	$	260		$	169

Segment_Reporting_Tables

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting, Measurement Disclosures [Abstract]
Schedule Of Significant Components Of The Company's Revenues And Expenses	A summary of the significant components of the Company’s revenues and expenses is as follows:
		Twelve months ended December 31, 2014	Catastrophe Reinsurance			Specialty Reinsurance			Lloyd’s			Other			Total
		Gross premiums written (1)	$	933,969		$	346,638		$	269,656		$	309		$	1,550,572
		Net premiums written	$	541,608		$	295,855		$	230,429		$	344		$	1,068,236
		Net premiums earned	$	590,845		$	253,537		$	217,666		$	368		$	1,062,416
		Net claims and claim expenses incurred	1,757			88,502			113,825			(6,137		)	197,947
		Acquisition expenses	43,161			60,936			46,927			(6,548		)	144,476
		Operational expenses	95,851			43,370			51,115			303			190,639
		Underwriting income	$	450,076		$	60,729		$	5,799		$	12,750		529,354
		Net investment income										124,316			124,316
		Net foreign exchange gains										6,260			6,260
		Equity in earnings of other ventures										26,075			26,075
		Other loss										(423		)	(423		)
		Net realized and unrealized gains on investments										41,433			41,433
		Corporate expenses										(22,987		)	(22,987		)
		Interest expense										(17,164		)	(17,164		)
		Income before taxes and noncontrolling interests													686,864
		Income tax expense										(608		)	(608		)
		Net income attributable to noncontrolling interests										(153,538		)	(153,538		)
		Dividends on preference shares										(22,381		)	(22,381		)
		Net income available to RenaissanceRe common shareholders													$	510,337
		Net claims and claim expenses incurred – current accident year	$	67,268		$	144,411		$	130,066		$	—		$	341,745
		Net claims and claim expenses incurred – prior accident years	(65,511		)	(55,909		)	(16,241		)	(6,137		)	(143,798		)
		Net claims and claim expenses incurred – total	$	1,757		$	88,502		$	113,825		$	(6,137	)	$	197,947
		Net claims and claim expense ratio – current accident year	11.4		%	57		%	59.8		%	—		%	32.2		%
		Net claims and claim expense ratio – prior accident years	(11.1		)%	(22.1		)%	(7.5		)%	(1,667.7		)%	(13.6		)%
		Net claims and claim expense ratio – calendar year	0.3		%	34.9		%	52.3		%	(1,667.7		)%	18.6		%
		Underwriting expense ratio	23.5		%	41.1		%	45		%	(1,697.0		)%	31.6		%
		Combined ratio	23.8		%	76		%	97.3		%	(3,364.7		)%	50.2		%
	(1) Included in gross premiums written in the Other category is inter-segment gross premiums written of $0.3 million.
		Twelve months ended December 31, 2013	Catastrophe Reinsurance			Specialty Reinsurance			Lloyd’s			Other			Total
		Gross premiums written (1)	$	1,120,379		$	259,489		$	226,532		$	(988	)	$	1,605,412
		Net premiums written	$	753,078		$	248,562		$	201,697		$	610		$	1,203,947
		Net premiums earned	$	723,705		$	214,306		$	176,029		$	586		$	1,114,626
		Net claims and claim expenses incurred	7,908			67,236			95,693			450			171,287
		Acquisition expenses	49,161			41,538			34,823			(21		)	125,501
		Operational expenses	108,130			31,780			50,540			655			191,105
		Underwriting income (loss)	$	558,506		$	73,752		$	(5,027	)	$	(498	)	626,733
		Net investment income										208,028			208,028
		Net foreign exchange gains										1,917			1,917
		Equity in earnings of other ventures										23,194			23,194
		Other loss										(2,359		)	(2,359		)
		Net realized and unrealized gains on investments										35,076			35,076
		Corporate expenses										(33,622		)	(33,622		)
		Interest expense										(17,929		)	(17,929		)
		Income from continuing operations before taxes and noncontrolling interests													841,038
		Income tax expense										(1,692		)	(1,692		)
		Income from discontinued operations										2,422			2,422
		Net income attributable to noncontrolling interests										(151,144		)	(151,144		)
		Dividends on preference shares										(24,948		)	(24,948		)
		Net income available to RenaissanceRe common shareholders													$	665,676
		Net claims and claim expenses incurred – current accident year	$	109,945		$	101,347		$	103,949		$	—		$	315,241
		Net claims and claim expenses incurred – prior accident years	(102,037		)	(34,111		)	(8,256		)	450			(143,954		)
		Net claims and claim expenses incurred – total	$	7,908		$	67,236		$	95,693		$	450		$	171,287
		Net claims and claim expense ratio – current accident year	15.2		%	47.3		%	59.1		%	—		%	28.3		%
		Net claims and claim expense ratio – prior accident years	(14.1		)%	(15.9		)%	(4.7		)%	76.8		%	(12.9		)%
		Net claims and claim expense ratio – calendar year	1.1		%	31.4		%	54.4		%	76.8		%	15.4		%
		Underwriting expense ratio	21.7		%	34.2		%	48.5		%	108.2		%	28.4		%
		Combined ratio	22.8		%	65.6		%	102.9		%	185		%	43.8		%
	(1) Included in gross premiums written in the Other category is inter-segment gross premiums written of $(1.0) million.
		Year ended December 31, 2012	Catastrophe Reinsurance			Specialty Reinsurance			Lloyd’s			Other			Total
		Gross premiums written (1)	$	1,182,207		$	209,887		$	159,987		$	(490	)	$	1,551,591
		Net premiums written	$	766,035		$	201,552		$	135,131		$	(61	)	$	1,102,657
		Net premiums earned	$	781,738		$	164,685		$	122,968		$	(36	)	$	1,069,355
	Net claims and claim expenses incurred	165,209			76,813			80,242			2,947			325,211
	Acquisition expenses	66,665			23,826			22,864			187			113,542
	Operational expenses	103,811			29,124			45,680			536			179,151
	Underwriting income (loss)	$	446,053		$	34,922		$	(25,818	)	$	(3,706	)	451,451
	Net investment income										165,725			165,725
	Net foreign exchange gains										5,319			5,319
	Equity in earnings of other ventures										23,238			23,238
	Other loss										(2,120		)	(2,120		)
	Net realized and unrealized gains on investments										163,121			163,121
	Net other-than-temporary impairments										(343		)	(343		)
	Corporate expenses										(16,456		)	(16,456		)
	Interest expense										(23,097		)	(23,097		)
	Income from continuing operations before taxes													766,838
	Income tax expense										(1,413		)	(1,413		)
	Loss from discontinued operations										(16,476		)	(16,476		)
	Net income attributable to noncontrolling interests										(148,040		)	(148,040		)
	Dividends on preference shares										(34,895		)	(34,895		)
	Net income attributable to RenaissanceRe common shareholders													$	566,014
	Net claims and claim expenses incurred – current accident year	$	275,777		$	110,959		$	96,444		$	—		$	483,180
	Net claims and claim expenses incurred – prior accident years	(110,568		)	(34,146		)	(16,202		)	2,947			(157,969		)
	Net claims and claim expenses incurred – total	$	165,209		$	76,813		$	80,242		$	2,947		$	325,211
	Net claims and claim expense ratio – current accident year	35.3		%	67.4		%	78.4		%	—		%	45.2		%
	Net claims and claim expense ratio – prior accident years	(14.2		)%	(20.8		)%	(13.1		)%	(8,186.1		)%	(14.8		)%
	Net claims and claim expense ratio – calendar year	21.1		%	46.6		%	65.3		%	(8,186.1		)%	30.4		%
	Underwriting expense ratio	21.8		%	32.2		%	55.7		%	(2,008.3		)%	27.4		%
	Combined ratio	42.9		%	78.8		%	121		%	(10,194.4		)%	57.8		%
(1) Included in gross premiums written in the Other category is inter-segment gross premiums written of $0.5 million.
Schedule of Gross Premiums Written Allocated to the Territory of Coverage Exposure	The following is a summary of the Company’s gross premiums written allocated to the territory of coverage exposure:
		Year ended December 31,	2014			2013			2012
		Catastrophe Reinsurance
		U.S. and Caribbean	$	573,696		$	782,211		$	857,740
		Worldwide	157,674			99,179			81,595
		Worldwide (excluding U.S.) (1)	123,476			146,048			139,265
		Japan	31,484			39,060			43,238
		Europe	25,353			25,659			37,113
		Australia and New Zealand	20,807			22,460			18,578
		Other	1,479			5,762			4,678
		Total Catastrophe Reinsurance	933,969			1,120,379			1,182,207
		Specialty Reinsurance
		U.S. and Caribbean	169,045			91,203			69,070
		Worldwide	161,329			151,879			96,081
		Australia and New Zealand	6,898			12,068			28,307
		Worldwide (excluding U.S.) (1)	7,506			1,661			—
		Europe	460			2,612			16,429
		Other	1,400			66			—
		Total Specialty Reinsurance	346,638			259,489			209,887
		Lloyd’s
		U.S. and Caribbean	120,066			88,535			57,332
		Worldwide	118,190			104,249			75,132
		Worldwide (excluding U.S.) (1)	13,655			8,071			6,064
		Europe	7,609			14,763			14,456
		Australia and New Zealand	2,907			2,948			2,152
		Other	7,229			7,966			4,851
		Total Lloyd’s	269,656			226,532			159,987
		Other category (2)	309			(988		)	(490		)
		Total gross premiums written	$	1,550,572		$	1,605,412		$	1,551,591
	-1	The category “Worldwide (excluding U.S.)” consists of contracts that cover more than one geographic region (other than the U.S.). The exposure in this category for gross premiums written to date is predominantly from Europe and Japan.
	-2	The Other category consists of contracts that are primarily exposed to U.S. risks and includes inter-segment gross premiums written of $0.3 million for the year ended December 31, 2014 (2013 - $(1.0) million, 2012 - $(0.5) million).

Stock_Incentive_Compensation_a1

Stock Incentive Compensation and Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Payment Award, Performance Shares, Valuation Assumptions	The following are the weighted average-assumptions used to estimate the fair value for all Performance Shares issued in each respective year.
			Performance Shares
		Year ended December 31,	2014		2013
		Expected volatility (1)	14.5% - 18.6%		19.0% - 19.6%
		Expected term (in years)	n/a		n/a
		Expected dividend yield	n/a		n/a
		Risk-free interest rate (1)	0.08% - 1.65%		0.09% - 1.39%
	-1	The expected volatility and risk-free interest rate applied are specific to each tranche of Performance Shares.
Schedule of Share-based Compensation, 2001 Stock Incentive Plan, Non-Employee Director Stock Incentive Plan and Premium Option Plan	Premium Option Plan
			Weighted			Weighted			Weighted		Aggregate			Range of exercise
			options			average			average		intrinsic  value			prices
			outstanding			exercise price			remaining
									contractual
									life
		Balance, December 31, 2011	1,192,000			$	73.94				$	—		$73.06 - $74.24
		Options granted	—			—
		Options forfeited	—			—
		Options expired	—			—
		Options exercised	(350,000	)		74.24					1,250
		Balance, December 31, 2012	842,000			$	73.82				$	6,265		$73.06 - $74.24
		Options granted	—			—
		Options forfeited	—			—
		Options expired	—			—
		Options exercised	(270,000	)		74.24					4,921
		Balance, December 31, 2013	572,000			$	73.62				$	13,567		$73.06 - $74.24
		Options granted	—			—
		Options forfeited	—			—
		Options expired	—			—
		Options exercised	(572,000	)		73.62					13,414
		Balance, December 31, 2014	—			$	—		0		$	—		$	—
		Total options exercisable at December 31, 2014	—			$	—		0		$	—		$	—
	2001 Stock Incentive and Non-Employee Director Stock Incentive Plans
			Weighted			Weighted			Weighted		Aggregate			Range of exercise prices
			options			average			average		intrinsic
			outstanding			exercise price			remaining		value
									contractual
									life
		Balance, December 31, 2011	1,973,307			$	47.33		4.6		$	53,363		$37.51 - $59.66
		Options granted	—			—								—
		Options forfeited	—			—
		Options expired	—			—
		Options exercised	(240,668	)		45.3					$	7,910
		Balance, December 31, 2012	1,732,639			$	47.61		3.7		$	58,305		$37.51 - $59.66
		Options granted	—			—								—
		Options forfeited	—			—
		Options expired	—			—
		Options exercised	(904,547	)		46.55					$	36,800
		Balance, December 31, 2013	828,092			$	48.77		2.9		$	40,221		$37.51 - $59.66
		Options granted	—			—								—
		Options forfeited	—			—
		Options expired	—			—
		Options exercised	(60,262	)		$	49.52				$	2,900
		Balance, December 31, 2014	767,830			$	48.71		2		$	37,246		$37.51 - $59.66
		Total options exercisable at December 31, 2014	767,830			$	48.71		2		$	37,246		$37.51 - $59.66
Schedule of Share-based Compensation, 2010 Cash Settled Restricted Stock Unit Plan and 2010 Performance-Based Equity Incentive Plan	2010 Cash Settled Restricted Stock Unit Plan and 2010 Performance-Based Equity Incentive Plan
			Cash Settled			Performance Shares (1)
			Restricted
			Stock
			Unit Plan
			Number of			Number of		Weighted
			shares			shares		average
								grant-date fair value
		Nonvested at December 31, 2011	422,973			289,867		$	30.06
		Awards granted	225,105			144,635		$	28.17
		Awards vested	(128,401	)		(70,843	)
		Awards forfeited	(26,121	)		(4,139	)
		Nonvested at December 31, 2012	493,556			359,520		$	29.46
		Awards granted	149,760			134,358		$	33.46
		Awards vested	(176,265	)		(24,606	)
		Awards forfeited	(72,906	)		(109,729	)
		Nonvested at December 31, 2013	394,145			359,543		$	30.55
		Awards granted	119,382			102,668		$	46.45
		Awards vested	(159,094	)		—
		Awards forfeited	(16,110	)		(213,639	)
		Nonvested at December 31, 2014	338,323			248,572		$	39.62
	(1) For Performance Shares, the number of shares is stated at the maximum number that can be attained if the performance conditions are fully met. Forfeitures represent shares forfeited due to vesting below the maximum attainable as a result of the Company not fully meeting the performance conditions.
Schedule of Share-based Compensation, Restricted Stock	Restricted Stock
			Employee						Non-employee director						Total
			restricted stock						restricted stock						restricted stock
			Number of			Weighted			Number of			Weighted			Number of		Weighted
			shares			average grant			shares			average grant			shares		average grant
						date fair						date fair					date fair
						value						value					value
		Nonvested at December 31, 2011	764,761			$	53.68		39,585			$	58.43		804,346		$	53.91
		Awards granted	226,827			72.46			16,874			71.69			243,701		72.4
		Awards vested	(337,683	)		51.06			(20,536	)		54.62			(358,219	)	51.26
		Awards forfeited	(7,157	)		53.9			—			—			(7,157	)	53.9
		Nonvested at December 31, 2012	646,748			$	61.63		35,923			$	66.83		682,671		$	61.9
		Awards granted	241,071			87.85			17,162			87.4			258,233		87.82
		Awards vested	(311,334	)		55.63			(21,599	)		66.06			(332,933	)	56.31
		Awards forfeited	(6,993	)		58.14			—			—			(6,993	)	58.14
		Nonvested at December 31, 2013	569,492			$	76.11		31,486			$	78.57		600,978		$	76.24
		Awards granted	215,054			95.79			14,455			95.06			229,509		95.74
		Awards vested	(332,725	)		73.74			(15,886	)		74.96			(348,611	)	73.79
		Awards forfeited	(99	)		55.8			—			—			(99	)	55.8
		Nonvested at December 31, 2014	451,722			$	87.29		30,055			$	88.41		481,777		$	87.36

Statutory_Requirements_Tables

Statutory Requirements (Tables)	12 Months Ended
	Dec. 31, 2014
Insurance [Abstract]
Schedule of Statutory Capital and Restricted Net Assets	The actual statutory capital and surplus, required statutory capital and surplus and restricted net assets of the Company’s regulated insurance operations in its most significant regulatory jurisdictions are detailed below:
			Bermuda					U.K. (1) (2)
		At December 31,	2014		2013			2014		2013
		Actual statutory capital and surplus	$	3,375,317	$	3,194,446		$	409,046	$	380,336
		Required statutory capital and surplus	479,346		562,126			409,046		380,336
		Restricted net assets	1,018,878		887,083			—		—
	-1	With respect to actual and required statutory capital and surplus, and as described below, underwriting capacity of a member of Lloyd’s must be supported by providing a deposit in the form of cash, securities or letters of credit, which are referred to as Funds at Lloyd’s (“FAL”). FAL is determined by Lloyd’s and is based on Syndicate 1458’s solvency and capital requirements as calculated through its internal model.
	-2	Syndicate 1458 is capitalized by its FAL, with the related assets not held on its balance sheet. As such, restricted net assets is not applicable to Syndicate 1458; however, the Company can make an application to obtain approval from Lloyd’s to have funds released to RenaissanceRe from Syndicate 1458, subject to passing a Lloyd’s release test.
Schedule of Statutory Net Income (Loss)	Statutory net income (loss) of the Company’s regulated insurance operations in its most significant regulatory jurisdictions are detailed below:
			Statutory Net Income (Loss)
			Bermuda		U.K.
		Year ended December 31, 2014	$	623,931	$	24,433
		Year ended December 31, 2013	712,820		7,745
		Year ended December 31, 2012	693,887		(10,967		)

Derivative_Instruments_Tables

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2014
Summary of Derivative Instruments [Abstract]
Schedule of Location on Consolidated Balance Sheets and Fair Value Of Principal Derivative Instruments	The tables below show the gross and net amounts of recognized derivative assets and liabilities, including the location on the consolidated balance sheets and fair value of the Company’s principal derivative instruments:
			Derivative Assets
		At December 31, 2014	Gross Amounts of Recognized Assets				Gross Amounts Offset in the Balance Sheet				Net Amounts of Assets Presented in the Balance Sheet				Balance Sheet Location	Collateral		Net Amount
		Interest rate futures	$	468			468				$	—			Other assets	$	—	$	—
		Foreign currency forward contracts (1)	5,740				1,737				4,003				Other assets	—		4,003
		Foreign currency forward contracts (2)	3,959				648				3,311				Other assets	—		3,311
		Credit default swaps	468				88				380				Other assets	310		70
		Total	$	10,635			$	2,941			$	7,694				$	310	$	7,384
			Derivative Liabilities
		At December 31, 2014	Gross Amounts of Recognized Liabilities				Gross Amounts Offset in the Balance Sheet				Net Amounts of Liabilities Presented in the Balance Sheet				Balance Sheet Location	Collateral Pledged		Net Amount
		Interest rate futures	$	1,037			468				$	569			Other liabilities	$	569	$	—
		Foreign currency forward contracts (1)	1,319				967				352				Other liabilities	—		352
		Foreign currency forward contracts (2)	724				649				75				Other liabilities	—		75
		Credit default swaps	251				88				163				Other liabilities	—		163
		Weather contract	190				—				190				Other liabilities	190		—
		Total	$	3,521			$	2,172			$	1,349				$	759	$	590
	-1	Contracts used to manage foreign currency risks in underwriting and non-investment operations.
	-2	Contracts used to manage foreign currency risks in investment operations.
			Derivative Assets
		At December 31, 2013	Gross Amounts of Recognized Assets				Gross Amounts Offset in the Balance Sheet				Net Amounts of Assets Presented in the Balance Sheet				Balance Sheet Location	Collateral		Net Amount
		Interest rate futures	$	897			62				$	835			Other assets	$	—	$	835
		Foreign currency forward contracts (1)	9,612				1,179				8,433				Other assets	—		8,433
		Foreign currency forward contracts (2)	1,013				338				675				Other assets	—		675
		Credit default swaps	806				82				724				Other assets	310		414
		Total	$	12,328			$	1,661			$	10,667				$	310	$	10,357
			Derivative Liabilities
		At December 31, 2013	Gross Amounts of Recognized Liabilities				Gross Amounts Offset in the Balance Sheet				Net Amounts of Liabilities Presented in the Balance Sheet				Balance Sheet Location	Collateral Pledged		Net Amount
		Interest rate futures	$	74			62				$	12			Other liabilities	$	12	$	—
		Foreign currency forward contracts (1)	2,204				28				2,176				Other liabilities	—		2,176
		Foreign currency forward contracts (2)	1,557				338				1,219				Other liabilities	—		1,219
		Credit default swaps	94				82				12				Other liabilities	—		12
		Weather contract	2,490				—				2,490				Other liabilities	2,490		—
		Total	$	6,419			$	510			$	5,909				$	2,502	$	3,407
	-1	Contracts used to manage foreign currency risks in underwriting and non-investment operations.
	-2	Contracts used to manage foreign currency risks in investment operations.
Schedule of Gain (Loss) Recognized In Consolidated Statements Of Operations Related To Principal Derivative Instruments	The location and amount of the gain (loss) recognized in the Company’s consolidated statements of operations related to its principal derivative instruments are shown in the following table:
			Location of gain (loss)		Amount of gain (loss) recognized on
			recognized on derivatives		derivatives
		Year ended December 31,			2014				2013				2012
		Interest rate futures	Net realized and unrealized gains on investments		$	(32,713	)		$	29,695			$	(1,746	)
		Foreign currency forward contracts (1)	Net foreign exchange gains		4,457				889				13,804
		Foreign currency forward contracts (2)	Net foreign exchange gains		12,623				(3,015		)		(3,445		)
		Credit default swaps	Net realized and unrealized gains on investments		328				1,363				1,074
		Weather contract	Net realized and unrealized gains on investments		1,454				(1,331		)		—
		Total			$	(13,851	)		$	27,601			$	9,687
	-1	Contracts used to manage foreign currency risks in underwriting and non-investment operations.
	-2	Contracts used to manage foreign currency risks in investment operations.

Commitments_Contingencies_and_1

Commitments, Contingencies and Other Items (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments for Operating Leases	Future minimum lease payments under existing operating leases are expected to be as follows:
			Minimum
			lease payments
		2015	$	6,184
		2016	5,234
		2017	2,321
		2018	2,035
		2019	1,455
		After 2019	142
		Future minimum lease payments under existing operating leases	$	17,371
Schedule of Future Minimum Lease Payments for Capital Leases	The future minimum lease payments of the Company’s capital leases are detailed below, and relate principally to the transaction noted above, excluding the bargain renewal option.
			Minimum
			lease payments
		2015	$	3,017
		2016	3,017
		2017	2,417
		2018	2,501
		2019	2,661
		After 2019	23,433
		Future minimum lease payments under existing capital leases	$	37,046

Quarterly_Financial_Informatio1

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Data [Abstract]
Quarterly Financial Information (Unaudited)
			Quarter Ended						Quarter Ended						Quarter Ended						Quarter Ended
			March 31,						June 30,						September 30,						December 31,
			2014			2013			2014			2013			2014			2013			2014			2013
		Revenues
		Gross premiums written	$	705,260		$	635,418		$	511,540		$	703,223		$	200,992		$	182,649		$	132,780		$	84,122
		Net premiums written	$	450,347		$	436,813		$	346,407		$	559,109		$	159,713		$	127,241		$	111,769		$	80,784
		(Increase) decrease in unearned premiums	(163,813		)	(165,558		)	(85,991		)	(267,220		)	99,266			167,476			144,718			175,981
		Net premiums earned	286,534			271,255			260,416			291,889			258,979			294,717			256,487			256,765
		Net investment income	38,948			43,202			34,541			26,163			24,941			59,931			25,886			78,732
		Net foreign exchange (losses) gains	(1,061		)	614			2,392			(932		)	5,036			488			(107		)	1,747
		Equity in earnings of other ventures	4,199			5,835			7,232			3,772			9,806			7,313			4,838			6,274
		Other income (loss)	62			(1,709		)	(535		)	(1,128		)	(1,169		)	651			1,219			(173		)
		Net realized and unrealized gains (losses) on investments	14,927			14,269			27,128			(69,529		)	(31,097		)	28,472			30,475			61,864
		Total revenues	343,609			333,466			331,174			250,235			266,496			391,572			318,798			405,209
		Expenses
		Net claims and claim expenses incurred	58,915			27,251			81,388			103,962			69,647			60,928			(12,003		)	(20,854		)
		Acquisition costs	33,700			25,009			33,477			31,767			37,550			37,699			39,749			31,026
		Operational expenses	42,624			45,986			45,841			42,789			46,972			44,672			55,202			57,658
		Corporate expenses	4,545			4,482			3,954			21,529			3,905			4,307			10,583			3,304
		Interest expense	4,293			5,034			4,292			4,300			4,290			4,298			4,289			4,297
		Total expenses	144,077			107,762			168,952			204,347			162,364			151,904			97,820			75,431
		Income from continuing operations before taxes	199,532			225,704			162,222			45,888			104,132			239,668			220,978			329,778
		Income tax (expense) benefit	(166		)	(122		)	204			(11		)	(245		)	(223		)	(401		)	(1,336		)
		Income from continuing operations	199,366			225,582			162,426			45,877			103,887			239,445			220,577			328,442
		Income (loss) from discontinued operations	—			9,774			—			2,427			—			(9,779		)	—			—
		Net income	199,366			235,356			162,426			48,304			103,887			229,666			220,577			328,442
		Net income attributable to noncontrolling interests	(42,768		)	(38,607		)	(36,078		)	(14,015		)	(30,477		)	(44,331		)	(44,215		)	(54,191		)
		Net income available to RenaissanceRe	156,598			196,749			126,348			34,289			73,410			185,335			176,362			274,251
		Dividends on preference shares	(5,595		)	(6,275		)	(5,596		)	(7,483		)	(5,595		)	(5,595		)	(5,595		)	(5,595		)
		Net income available to RenaissanceRe common shareholders	$	151,003		$	190,474		$	120,752		$	26,806		$	67,815		$	179,740		$	170,767		$	268,656
		Income from continuing operations available to RenaissanceRe common shareholders per common share – basic	$	3.61		$	4.1		$	3		$	0.55		$	1.72		$	4.32		$	4.46		$	6.14
		Income (loss) from discontinued operations available (attributable) to RenaissanceRe common shareholders per common share – basic	—			0.22			—			0.06			—			(0.23		)	—			—
		Net income available to RenaissanceRe common shareholders per common share – basic	$	3.61		$	4.32		$	3		$	0.61		$	1.72		$	4.09		$	4.46		$	6.14
		Income from continuing operations available to RenaissanceRe common shareholders per common share – diluted	$	3.56		$	4.01		$	2.95		$	0.55		$	1.7		$	4.23		$	4.42		$	6.05
		Income (loss) from discontinued operations available (attributable) to RenaissanceRe common shareholders per common share – diluted	—			0.22			—			0.05			—			(0.22		)	—			—
		Net income available to RenaissanceRe common shareholders per common share – diluted	$	3.56		$	4.23		$	2.95		$	0.6		$	1.7		$	4.01		$	4.42		$	6.05
		Average shares outstanding – basic	41,238			43,461			39,736			43,372			38,975			43,330			37,752			43,160
		Average shares outstanding – diluted	41,903			44,290			40,395			44,243			39,433			44,135			38,145			43,769

Condensed_Consolidating_Financ1

Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2014
Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries [Abstract]
Condensed Consolidating Balance Sheet
	Condensed Consolidating Balance Sheet at December 31, 2014	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
		Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
		(Parent			Holdings Inc.			Holdings Ltd.			-2
		Guarantor)			(Subsidiary			Subsidiaries and
					Issuer)			Eliminations
								(Non-guarantor
								Subsidiaries)
								-1
	Assets
	Total investments	$	137,006		$	88,150		$	6,518,594		$	—		$	6,743,750
	Cash and cash equivalents	5,986			1,033			518,565			—			525,584
	Investments in subsidiaries	3,509,974			71,796			—			(3,581,770		)	—
	Due from subsidiaries and affiliates	126,548			23			—			(126,571		)	—
	Premiums receivable	—			—			440,007			—			440,007
	Prepaid reinsurance premiums	—			—			94,810			—			94,810
	Reinsurance recoverable	—			—			66,694			—			66,694
	Accrued investment income	—			121			26,388			—			26,509
	Deferred acquisition costs	—			—			110,059			—			110,059
	Receivable for investments sold	10			—			52,380			—			52,390
	Other assets	112,400			1,242			131,563			(101,458		)	143,747
	Total assets	$	3,891,924		$	162,365		$	7,959,060		$	(3,809,799	)	$	8,203,550
	Liabilities, Noncontrolling Interests and Shareholders’ Equity
	Liabilities
	Reserve for claims and claim expenses	$	—		$	—		$	1,412,510		$	—		$	1,412,510
	Unearned premiums	—			—			512,386			—			512,386
	Debt	—			249,522			—			—			249,522
	Amounts due to subsidiaries and affiliates	6,000			233			—			(6,233		)	—
	Reinsurance balances payable	—			—			454,580			—			454,580
	Payable for investments purchased	—			—			203,021			—			203,021
	Other liabilities	20,209			4,013			351,344			(1,458		)	374,108
	Total liabilities	26,209			253,768			2,933,841			(7,691		)	3,206,127
	Redeemable noncontrolling interests	—			—			1,131,708			—			1,131,708
	Shareholders’ Equity
	Total shareholders’ equity	3,865,715			(91,403		)	3,893,511			(3,802,108		)	3,865,715
	Total liabilities, noncontrolling interests and shareholders’ equity	$	3,891,924		$	162,365		$	7,959,060		$	(3,809,799	)	$	8,203,550
	-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
	-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
	Condensed Consolidating Balance Sheet at December 31, 2013	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
		Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
		(Parent			Holdings Inc.			Holdings Ltd.			-2
		Guarantor)			(Subsidiary			Subsidiaries and
					Issuer)			Eliminations
								(Non-guarantor
								Subsidiaries)
								-1
	Assets
	Total investments	$	210,719		$	98,784		$	6,512,209		$	—		$	6,821,712
	Cash and cash equivalents	8,796			4,027			395,209			—			408,032
	Investments in subsidiaries	3,294,729			74,718			—			(3,369,447		)	—
	Due from subsidiaries and affiliates	296,752			—			—			(296,752		)	—
	Premiums receivable	—			—			474,087			—			474,087
	Prepaid reinsurance premiums	—			—			66,132			—			66,132
	Reinsurance recoverable	—			—			101,025			—			101,025
	Accrued investment income	—			110			33,955			—			34,065
	Deferred acquisition costs	—			—			81,684			—			81,684
	Receivable for investments sold	14			—			75,831			—			75,845
	Other assets	112,234			1,481			102,834			(100,000		)	116,549
	Total assets	$	3,923,244		$	179,120		$	7,842,966		$	(3,766,199	)	$	8,179,131
	Liabilities, Redeemable Noncontrolling Interest and Shareholders’ Equity
	Liabilities
	Reserve for claims and claim expenses	$	—		$	—		$	1,563,730		$	—		$	1,563,730
	Unearned premiums	—			—			477,888			—			477,888
	Debt	—			249,430			—			—			249,430
Amounts due to subsidiaries and affiliates	—			3,173			—			(3,173		)	—
Reinsurance balances payable	—			—			293,022			—			293,022
Payable for investments purchased	—			—			193,221			—			193,221
Other liabilities	18,860			6,953			371,783			—			397,596
Total liabilities	18,860			259,556			2,899,644			(3,173		)	3,174,887
Redeemable noncontrolling interest	—			—			1,099,860			—			1,099,860
Shareholders’ Equity
Total shareholders’ equity	3,904,384			(80,436		)	3,843,462			(3,763,026		)	3,904,384
Total liabilities, redeemable noncontrolling interest and shareholders’ equity	$	3,923,244		$	179,120		$	7,842,966		$	(3,766,199	)	$	8,179,131
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement of Operations
	Condensed Consolidating Statement of Operations	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
	for the year ended December 31, 2012	Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
		(Parent			Holdings Inc.			Holdings Ltd.			-2
		Guarantor)			(Subsidiary			Subsidiaries
					Issuer)			and
								Eliminations
								(Non-guarantor
								Subsidiaries)
								-1
	Revenues
	Net premiums earned	$	—		$	—		$	1,069,355		$	—		$	1,069,355
	Net investment income	14,195			619			150,911			—			165,725
	Net foreign exchange gains	33			—			5,286			—			5,319
	Equity in earnings of other ventures	—			—			23,238			—			23,238
	Other income (loss)	2,822			—			(4,942		)	—			(2,120		)
	Net realized and unrealized gains on investments	14,862			1,556			146,703			—			163,121
	Net other-than-temporary impairments	—			—			(343		)	—			(343		)
	Total revenues	31,912			2,175			1,390,208			—			1,424,295
	Expenses
	Net claims and claim expenses incurred	—			—			325,211			—			325,211
	Acquisition expenses	—			—			113,542			—			113,542
	Operational expenses	(5,103		)	7,013			177,241			—			179,151
	Corporate expenses	14,282			273			1,901			—			16,456
	Interest expense	5,875			14,467			2,755			—			23,097
	Total expenses	15,054			21,753			620,650			—			657,457
	Income (loss) before equity in net loss of subsidiaries and taxes	16,858			(19,578		)	769,558			—			766,838
	Equity in net earnings of subsidiaries	584,051			1,860			—			(585,911		)	—
	Income (loss) from continuing operations before taxes	600,909			(17,718		)	769,558			(585,911		)	766,838
	Income tax expense	—			(499		)	(914		)	—			(1,413		)
	Income (loss) from continuing operations	600,909			(18,217		)	768,644			(585,911		)	765,425
	Loss from discontinued operations	—			(16,476		)	—			—			(16,476		)
	Net income (loss)	600,909			(34,693		)	768,644			(585,911		)	748,949
	Net income attributable to noncontrolling interest	—			—			(148,040		)	—			(148,040		)
	Net income (loss) attributable to RenaissanceRe	600,909			(34,693		)	620,604			(585,911		)	600,909
	Dividends on preference shares	(34,895		)	—			—			—			(34,895		)
	Net income (loss) available (attributable) to RenaissanceRe common shareholders	$	566,014		$	(34,693	)	$	620,604		$	(585,911	)	$	566,014
	-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
	-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
	Condensed Consolidating Statement of Operations	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
	for the year ended December 31, 2013	Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
		(Parent			Holdings Inc.			Holdings Ltd.			-2
		Guarantor)			(Subsidiary			Subsidiaries
					Issuer)			and
								Eliminations
								(Non-guarantor
								Subsidiaries)
								-1
	Revenues
	Net premiums earned	$	—		$	—		$	1,114,626		$	—		$	1,114,626
	Net investment income	4,213			488			209,105			(5,778		)	208,028
	Net foreign exchange (losses) gains	(7		)	(2		)	1,926			—			1,917
	Equity in earnings of other ventures	—			—			23,194			—			23,194
	Other income (loss)	106			125			(2,590		)	—			(2,359		)
	Net realized and unrealized (losses) gains on investments	(483		)	1,196			34,363			—			35,076
	Total revenues	3,829			1,807			1,380,624			(5,778		)	1,380,482
	Expenses
	Net claims and claim expenses incurred	—			—			171,287			—			171,287
	Acquisition expenses	—			—			125,501			—			125,501
	Operational expenses	(4,962		)	7,566			189,117			(616		)	191,105
	Corporate expenses	31,264			338			2,020			—			33,622
	Interest expense	734			14,467			2,728			—			17,929
	Total expenses	27,036			22,371			490,653			(616		)	539,444
	Loss (income) before equity in net loss of subsidiaries and taxes	(23,207		)	(20,564		)	889,971			(5,162		)	841,038
Equity in net income of subsidiaries	713,831			2,142			—			(715,973		)	—
Income (loss) from continuing operations before taxes	690,624			(18,422		)	889,971			(721,135		)	841,038
Income tax expense	—			(1,558		)	(134		)	—			(1,692		)
Income (loss) from continuing operations	690,624			(19,980		)	889,837			(721,135		)	839,346
Income from discontinued operations	—			2,422			—			—			2,422
Net income (loss)	690,624			(17,558		)	889,837			(721,135		)	841,768
Net income attributable to noncontrolling interest	—			—			(151,144		)	—			(151,144		)
Net income (loss) attributable to RenaissanceRe	690,624			(17,558		)	738,693			(721,135		)	690,624
Dividends on preference shares	(24,948		)	—			—			—			(24,948		)
Net income (loss) available (attributable) to RenaissanceRe common shareholders	$	665,676		$	(17,558	)	$	738,693		$	(721,135	)	$	665,676
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement of Operations for	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
the year ended December 31, 2014	Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
	(Parent			Holdings Inc.			Holdings Ltd.			-2
	Guarantor)			(Subsidiary			Subsidiaries and
				Issuer)			Eliminations
							(Non-guarantor
							Subsidiaries)
							-1
Revenues
Net premiums earned	$	—		$	—		$	1,062,416		$	—		$	1,062,416
Net investment income	2,706			1,765			123,582			(3,737		)	124,316
Net foreign exchange (losses) gains	(13		)	—			6,273			—			6,260
Equity in earnings of other ventures	—			—			26,075			—			26,075
Other loss	—			(7		)	(416		)	—			(423		)
Net realized and unrealized gains on investments	83			9,069			32,281			—			41,433
Total revenues	2,776			10,827			1,250,211			(3,737		)	1,260,077
Expenses
Net claims and claim expenses incurred	—			—			197,947			—			197,947
Acquisition expenses	—			—			144,476			—			144,476
Operational expenses	(4,890		)	7,004			188,857			(332		)	190,639
Corporate expenses	20,787			238			1,962			—			22,987
Interest expense	—			14,467			2,697			—			17,164
Total expenses	15,897			21,709			535,939			(332		)	573,213
(Loss) income before equity in net income of subsidiaries and taxes	(13,121		)	(10,882		)	714,272			(3,405		)	686,864
Equity in net income (loss) of subsidiaries	545,839			(4,343		)	—			(541,496		)	—
Income (loss) before taxes and noncontrolling interest	532,718			(15,225		)	714,272			(544,901		)	686,864
Income tax benefit (expense)	—			4,064			(4,672		)	—			(608		)
Net income (loss)	532,718			(11,161		)	709,600			(544,901		)	686,256
Net income attributable to noncontrolling interests	—			—			(153,538		)	—			(153,538		)
Net income (loss) attributable to RenaissanceRe	532,718			(11,161		)	556,062			(544,901		)	532,718
Dividends on preference shares	(22,381		)	—			—			—			(22,381		)
Net income (loss) attributable to RenaissanceRe common shareholders	$	510,337		$	(11,161	)	$	556,062		$	(544,901	)	$	510,337
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement of Comprehensive Income
	Condensed Consolidating Statement of Comprehensive Income (Loss) for the year ended December 31, 2012	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
		Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
		(Parent			Holdings Inc.			Holdings Ltd.			-2
		Guarantor)			(Subsidiary			Subsidiaries
					Issuer)			and
								Eliminations
								(Non-guarantor
								Subsidiaries)
								-1
	Comprehensive income (loss)
	Net income (loss)	$	600,909		$	(34,693	)	$	768,644		$	(585,911	)	$	748,949
	Change in net unrealized gains on investments	—			—			1,914			—			1,914
	Portion of other-than-temporary impairments recognized in other comprehensive loss	—			—			(52		)	—			(52		)
	Comprehensive income (loss)	600,909			(34,693		)	770,506			(585,911		)	750,811
	Net income attributable to noncontrolling interests	—			—			(148,040		)	—			(148,040		)
	Comprehensive income attributable to noncontrolling interests	—			—			(148,040		)	—			(148,040		)
	Comprehensive income (loss) attributable to RenaissanceRe	$	600,909		$	(34,693	)	$	622,466		$	(585,911	)	$	602,771
	-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
	-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
	Condensed Consolidating Statement of Comprehensive Income (Loss) for the year ended December 31, 2013	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
		Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
		(Parent			Holdings Inc.			Holdings Ltd.			-2
		Guarantor)			(Subsidiary			Subsidiaries
					Issuer)			and
								Eliminations
								(Non-guarantor
								Subsidiaries)
								-1
	Comprehensive income (loss)
	Net income (loss)	$	690,624		$	(17,558	)	$	889,837		$	(721,135	)	$	841,768
	Change in net unrealized gains on investments	—			—			(9,491		)	—			(9,491		)
	Comprehensive income (loss)	690,624			(17,558		)	880,346			(721,135		)	832,277
	Net income attributable to noncontrolling interests	—			—			(151,144		)	—			(151,144		)
	Comprehensive income attributable to noncontrolling interests	—			—			(151,144		)	—			(151,144		)
	Comprehensive income (loss) available (attributable) to RenaissanceRe	$	690,624		$	(17,558	)	$	729,202		$	(721,135	)	$	681,133
	-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
	-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
	Condensed Consolidating Statement of Comprehensive Income (Loss) for the year ended December 31, 2014	RenaissanceRe			RenRe North			Other			Consolidating			RenaissanceRe
		Holdings Ltd.			America			RenaissanceRe			Adjustments			Consolidated
		(Parent			Holdings Inc.			Holdings Ltd.			-2
		Guarantor)			(Subsidiary			Subsidiaries
					Issuer)			and
								Eliminations
								(Non-guarantor
								Subsidiaries)
								-1
	Comprehensive income (loss)
	Net income (loss)	$	532,718		$	(11,161	)	$	709,600		$	(544,901	)	$	686,256
	Change in net unrealized gains on investments	—			—			(715		)	—			(715		)
	Comprehensive income (loss)	532,718			(11,161		)	708,885			(544,901		)	685,541
	Net income attributable to noncontrolling interests	—			—			(153,538		)	—			(153,538		)
	Comprehensive income attributable to noncontrolling interests	—			—			(153,538		)	—			(153,538		)
	Comprehensive income (loss) attributable to RenaissanceRe	$	532,718		$	(11,161	)	$	555,347		$	(544,901	)	$	532,003
	-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
	-2	Includes Parent Guarantor and Subsidiary Issuer consolidating adjustments.
Condensed Consolidating Statement Of Cash Flows
	Condensed Consolidating Statement of Cash Flows	RenaissanceRe			RenRe North			Other			RenaissanceRe
	for the year ended December 31, 2014	Holdings Ltd.			America			RenaissanceRe			Consolidated
		(Parent			Holdings Inc.			Holdings Ltd.
		Guarantor)			(Subsidiary			Subsidiaries
					Issuer)			and
								Eliminations
								(Non-guarantor
								Subsidiaries)
								-1
	Cash flows provided by (used in) operating activities
	Net cash provided by (used in) operating activities	$	429		$	(18,114	)	$	678,342		$	660,657
	Cash flows provided by (used in) investing activities
	Proceeds from sales and maturities of fixed maturity investments trading	88,273			20,487			7,573,813			7,682,573
	Purchases of fixed maturity investments trading	(88,341		)	(14,969		)	(7,535,868		)	(7,639,178		)
	Proceeds from sales and maturities of fixed maturity investments available for sale	—			—			7,088			7,088
	Net sales (purchases) of equity investments trading	—			13,761			(33,764		)	(20,003		)
	Net sales (purchases) of short term investments	73,717			225			(28,919		)	45,023
	Net sales of other investments	—			—			59,120			59,120
	Net sales of investments in other ventures	—			—			1,030			1,030
	Net sales of other assets	—			—			6,000			6,000
	Dividends and return of capital from subsidiaries	1,259,224			11,204			(1,270,428		)	—
	Contributions to subsidiaries	(759,456		)	(12,625		)	772,081			—
	Due to (from) subsidiary	6,315			(2,963		)	(3,352		)	—
	Net cash provided by (used in) investing activities	579,732			15,120			(453,199		)	141,653
	Cash flows used in financing activities
	Dividends paid – RenaissanceRe common shares	(45,912		)	—			—			(45,912		)
	Dividends paid – preference shares	(22,381		)	—			—			(22,381		)
	RenaissanceRe common share repurchases	(514,678		)	—			—			(514,678		)
	Net third party redeemable noncontrolling interest share transactions	—			—			(111,707		)	(111,707		)
	Net cash used in financing activities	(582,971		)	—			(111,707		)	(694,678		)
	Effect of exchange rate changes on foreign currency cash	—			—			9,920			9,920
	Net (decrease) increase in cash and cash equivalents	(2,810		)	(2,994		)	123,356			117,552
	Cash and cash equivalents, beginning of period	8,796			4,027			395,209			408,032
	Cash and cash equivalents, end of period	$	5,986		$	1,033		$	518,565		$	525,584
	-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
	Condensed Consolidating Statement of Cash Flows	RenaissanceRe			RenRe North			Other			RenaissanceRe
	for the year ended December 31, 2013	Holdings Ltd.			America			RenaissanceRe			Consolidated
		(Parent			Holdings Inc.			Holdings Ltd.
		Guarantor)			(Subsidiary			Subsidiaries
					Issuer)			and
								Eliminations
								(Non-guarantor
								Subsidiaries)
								-1
	Cash flows (used in) provided by operating activities
	Net cash (used in) provided by operating activities	$	(37,966	)	$	(7,583	)	$	841,270		$	795,721
	Cash flows provided by (used in) investing activities
	Proceeds from sales and maturities of fixed maturity investments trading	880,749			185,143			7,185,513			8,251,405
	Purchases of fixed maturity investments trading	(491,768		)	(160,422		)	(7,814,277		)	(8,466,467		)
	Proceeds from sales and maturities of fixed maturity investments available for sale	—			—			45,178			45,178
	Net (purchases) sales of equity investments trading	—			(81,437		)	48,382			(33,055		)
	Net sales (purchases) of short term investments	21,217			9,399			(277,587		)	(246,971		)
	Net sales of other investments	—			—			76,214			76,214
	Net purchases of investments in other ventures	—			—			(4,000		)	(4,000		)
	Net sales of other assets	—			—			2,181			2,181
	Dividends and return of capital from subsidiaries	504,241			83,593			(587,834		)	—
	Contributions to subsidiaries	(500,652		)	(38,117		)	538,769			—
	Due to (from) subsidiaries	17,446			(3,761		)	(13,685		)	—
	Net proceeds related to sale of discontinued operations	—			—			60,000			60,000
	Net cash provided by (used in) investing activities	431,233			(5,602		)	(741,146		)	(315,515		)
	Cash flows (used in) provided by financing activities
	Dividends paid – RenaissanceRe common shares	(49,267		)	—			—			(49,267		)
	Dividends paid – preference shares	(24,948		)	—			—			(24,948		)
RenaissanceRe common share repurchases	(207,410		)	—			—			(207,410		)
Net repayment of debt	(100,000		)	—			(2,436		)	(102,436		)
Redemption 6.08% Series C preference shares	(125,000		)	—			—			(125,000		)
Redemption 6.60% Series D preference shares	(150,000		)	—			—			(150,000		)
Issuance of 5.375% Series E preference shares, net of expenses	265,856			—			—			265,856
Contribution of capital from parent	—			15,684			(15,684		)	—
Net third party redeemable noncontrolling interest share transactions	—			—			(5,750		)	(5,750		)
Net cash (used in) provided by financing activities	(390,769		)	15,684			(23,870		)	(398,955		)
Effect of exchange rate changes on foreign currency cash	—			—			1,423			1,423
Net increase in cash and cash equivalents	2,498			2,499			77,677			82,674
Net decrease in cash and cash equivalents of discontinued operations	—			—			21,213			21,213
Cash and cash equivalents, beginning of period	6,298			1,528			296,319			304,145
Cash and cash equivalents, end of period	$	8,796		$	4,027		$	395,209		$	408,032
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.
Condensed Consolidating Statement of Cash Flows	RenaissanceRe			RenRe North			Other			RenaissanceRe
for the year ended December 31, 2012	Holdings Ltd.			America			RenaissanceRe			Consolidated
	(Parent			Holdings Inc.			Holdings Ltd.
	Guarantor)			(Subsidiary			Subsidiaries
				Issuer)			and
							Eliminations
							(Non-guarantor
							Subsidiaries)
							-1
Cash flows provided by (used in) operating activities
Net cash provided by (used in) operating activities	$	128,567		$	(10,376	)	$	598,738		$	716,929
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	744,211			140,626			7,308,030			8,192,867
Purchases of fixed maturity investments trading	(692,783		)	(73,800		)	(7,769,655		)	(8,536,238		)
Proceeds from sales and maturities of fixed maturity investments available for sale	—			—			65,168			65,168
Net (purchases) sales of short term investments	(80,485		)	(10,624		)	159,886			68,777
Net sales of other investments	—			—			150,828			150,828
Net purchases of other assets	—			—			(4,079		)	(4,079		)
Dividends and return of capital from subsidiaries	979,311			9,541			(988,852		)	—
Contributions to subsidiaries	(366,210		)	(50,000		)	416,210			—
Due (from) to subsidiary	(15,359		)	241			15,118			—
Net payments related to sale of discontinued operations	—			(9,000		)	—			(9,000		)
Net cash provided by (used in) investing activities	568,685			6,984			(647,346		)	(71,677		)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(53,356		)	—			—			(53,356		)
Dividends paid – preference shares	(34,895		)	—			—			(34,895		)
RenaissanceRe common share repurchases	(463,309		)	—			—			(463,309		)
Net repayment of debt	—			—			(1,937		)	(1,937		)
Redemption of 6.60% Series D preference shares	(150,000		)	—			—			(150,000		)
Third party DaVinciRe share repurchases	—			—			164,927			164,927
Net cash (used in) provided by financing activities	(701,560		)	—			162,990			(538,570		)
Effect of exchange rate changes on foreign currency cash	—			—			1,692			1,692
Net (decrease) increase in cash and cash equivalents	(4,308		)	(3,392		)	116,074			108,374
Net decrease in cash and cash equivalents of discontinued operations	—			—			13,946			13,946
Cash and cash equivalents, beginning of year	10,606			4,920			166,299			181,825
Cash and cash equivalents, end of year	$	6,298		$	1,528		$	296,319		$	304,145
-1	Includes all other subsidiaries of RenaissanceRe Holdings Ltd. and eliminations.

Organization_Details

Organization (Details) (RenaissanceRe Upsilon Fund Ltd, Not Primary Beneficiary)	0 Months Ended
	Nov. 13, 2014
RenaissanceRe Upsilon Fund Ltd | Not Primary Beneficiary
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonredeemable Nonvoting Shares, Segregated Funds, Owned by Third Parties	100.00%

Organization_Acquisition_Detai

Organization Acquisition (Details) (Scenario, Forecast, Platinum, USD $)	0 Months Ended
In Billions, unless otherwise specified	Mar. 02, 2015
Scenario, Forecast | Platinum
Business Acquisition [Line Items]
Aggregate consideration	$1.90

Discontinued_Operations_Narrat

Discontinued Operations (Narrative) (Details) (USD $)	0 Months Ended
In Millions, unless otherwise specified	Oct. 01, 2013	Mar. 04, 2011	Jun. 01, 2012
REAL
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of business	$60
Loss on sale	8.8
U.S.-based insurance operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of business		269.5
U.S.-based insurance operations | Reserve Collar
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Payment related to Reserve Collar			$9

Discontinued_Operations_Income

Discontinued Operations (Income (Loss) from Discontinued Operations) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues
Net investment income											$2,517
Net foreign exchange gains (losses)											-96
Other (loss) income											-18,055
Net realized and unrealized gains (losses) on fixed maturity investments											3
Total revenues											-15,631
Expenses [Abstract]
Operational expenses											586
Corporate expenses											236
Total expenses											822
(Loss) income before taxes											-16,453
Income tax expense											-23
(Loss) income from discontinued operations	0	0	0	0	0	-9,779	2,427	9,774	0	2,422	-16,476
REAL
Revenues
Net investment income										1,150	2,517
Net foreign exchange gains (losses)										849	-96
Other (loss) income										701	-20,785
Net realized and unrealized gains (losses) on fixed maturity investments										-18	3
Total revenues										2,682	-18,361
Expenses [Abstract]
Operational expenses										89	150
Corporate expenses										104	236
Total expenses										193	386
(Loss) income before taxes										2,489	-18,747
Income tax expense										-67	-16
(Loss) income from discontinued operations										2,422	-18,763
U.S.-based insurance operations
Revenues
Net investment income											0
Net foreign exchange gains (losses)											0
Other (loss) income											2,730
Net realized and unrealized gains (losses) on fixed maturity investments											0
Total revenues											2,730
Expenses [Abstract]
Operational expenses											436
Corporate expenses											0
Total expenses											436
(Loss) income before taxes											2,294
Income tax expense											-7
(Loss) income from discontinued operations											$2,287

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets (Schedule of Intangible Assets and Goodwill) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Other intangible assets
Gross amount, End of Period	$58,399	$58,477
Accumulated impairment losses and amortization, End of Period	-43,424	-39,560
Other intangible assets, Net, End of Period	14,975	18,917
Goodwill and Other intangible assets, Total
Goodwill and Other intangible assets, Net, End of Period	7,902	8,111
Excluding Equity Method Investments
Goodwill
Goodwill, Gross amount, Beginning of Period	8,160	8,160
Accumulated impairment losses and amortization, Beginning of Period	-2,299	-2,299
Goodwill, Net, Beginning of Period	5,861	5,861
Goodwill, Gross amount, End of Period	8,160	8,160
Accumulated impairment losses and amortization, End of Period	-2,299	-2,299
Goodwill, Net, End of Period	5,861	5,861
Other intangible assets
Gross amount, Beginning of Period	12,999	12,999
Accumulated impairment losses and amortization, Beginning of Period	-10,749	-10,374
Other intangible assets, Net, Beginning of Period	2,250	2,625
Amortization	-209	-375
Gross amount, End of Period	12,999	12,999
Accumulated impairment losses and amortization, End of Period	-10,958	-10,749
Other intangible assets, Net, End of Period	2,041	2,250
Goodwill and Other intangible assets, Total
Gross amount, Beginning of Period	21,159	21,159
Accumulated impairment losses and amortization, Beginning of Period	-13,048	-12,673
Goodwill and Other intangible assets, Net, Beginning of Period	8,111	8,486
Amortization	-209	-375
Gross amount, End of Period	21,159	21,159
Accumulated impairment losses and amortization, End of Period	-13,257	-13,048
Goodwill and Other intangible assets, Net, End of Period	$7,902	$8,111

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets (Schedule of Goodwill and Other Intangible Assets Included in Equity Method Investments) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Other intangible assets
Gross amount, End of Period	$58,399	$58,477
Accumulated impairment losses and amortization, End of Period	-43,424	-39,560
Other intangible assets, Net, End of Period	14,975	18,917
Goodwill and Other intangible assets, Total
Goodwill and Other intangible assets, Net, End of Period	7,902	8,111
Investments in other ventures
Goodwill
Goodwill, Gross amount, Beginning of Period	12,545	10,840
Accumulated impairment losses and amortization, Beginning of Period	0	0
Goodwill, Net, Beginning of Period	12,545	10,840
Acquired during the year		1,705
Adjustments to gross amounts	-227
Goodwill, Gross amount, End of Period	12,318	12,545
Accumulated impairment losses and amortization, End of Period	0	0
Goodwill, Net, End of Period	12,318	12,545
Other intangible assets
Gross amount, Beginning of Period	45,478	44,323
Accumulated impairment losses and amortization, Beginning of Period	-28,811	-24,769
Other intangible assets, Net, Beginning of Period	16,667	19,554
Acquired during the year		1,155
Amortization	-3,655	-4,042
Adjustments to gross amounts	-78
Gross amount, End of Period	45,400	45,478
Accumulated impairment losses and amortization, End of Period	-32,466	-28,811
Other intangible assets, Net, End of Period	12,934	16,667
Goodwill and Other intangible assets, Total
Gross amount, Beginning of Period	58,023	55,163
Accumulated impairment losses and amortization, Beginning of Period	-28,811	-24,769
Goodwill and Other intangible assets, Net, Beginning of Period	29,212	30,394
Acquired during the year		2,860
Amortization	-3,655	-4,042
Adjustments to gross amounts	305
Gross amount, End of Period	57,718	58,023
Accumulated impairment losses and amortization, End of Period	-32,466	-28,811
Goodwill and Other intangible assets, Net, End of Period	$25,252	$29,212

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets (Schedule of Finite-Lived Intangible Assets by Major Class) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	58,399	$58,477
Accumulated amortization and impairment losses	-43,424	-39,560
Other intangible assets, Net	14,975	18,917
Customer relationships and customer lists
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	40,562	40,640
Accumulated amortization and impairment losses	-28,057	-24,522
Other intangible assets, Net	12,505	16,118
Lloyd's managing agency license
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	1,867	1,867
Accumulated amortization and impairment losses	0	0
Other intangible assets, Net	1,867	1,867
Trademarks and trade names
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	610	610
Accumulated amortization and impairment losses	-159	-134
Other intangible assets, Net	451	476
Covenants not-to-compete
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	2,130	2,130
Accumulated amortization and impairment losses	-1,978	-1,674
Other intangible assets, Net	152	456
Software
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	8,730	8,730
Accumulated amortization and impairment losses	-8,730	-8,730
Other intangible assets, Net	0	0
Patents and intellectual property
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	4,500	4,500
Accumulated amortization and impairment losses	-4,500	-4,500
Other intangible assets, Net	0	$0
Minimum
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Finite-lived intangible assets, useful life	1 year
Maximum
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Finite-lived intangible assets, useful life	25 years
Weighted Average
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
Finite-lived intangible assets, useful life	11 years

Goodwill_and_Other_Intangible_5

Goodwill and Other Intangible Assets (Schedule of Expected Impairment Charges and Amortization Expense) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
2015	$3,165
2016	2,292
2017	1,914
2018	1,484
2019	1,041
2020 and thereafter	3,212
Total remaining amortization expense	13,108
Indefinite lived	1,867
Total	14,975
Other Intangible Assets
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
2015	174
2016	0
2017	0
2018	0
2019	0
2020 and thereafter	0
Total remaining amortization expense	174
Indefinite lived	1,867
Total	2,041
Other Intangible Assets | Investments in other ventures
Schedule of Finite and Indefinite-lived Intangible Assets [Line Items]
2015	2,991
2016	2,292
2017	1,914
2018	1,484
2019	1,041
2020 and thereafter	3,212
Total remaining amortization expense	12,934
Indefinite lived	0
Total	$12,934

Investments_Narrative_Details

Investments (Narrative) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investments [Abstract]
Cash and investments at fair value on deposit with, or in trust accounts for the benefit of, various counterparties	$2,379.40	$2,081.10
Cash and investments at fair value on deposit with, or in trust accounts for the benefit of, U.S. state regulatory authorities	691.9	652.8
Reverse repurchase agreements	$49.30	$37.30
Minimum percentage of collateral required	102.00%

Investments_Schedule_of_Fair_V

Investments (Schedule of Fair Value of Fixed Maturity Investments Trading) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investment [Line Items]
Fixed maturity investments trading, Fair value	$4,756,685	$4,809,036
U.S. treasuries
Investment [Line Items]
Fixed maturity investments trading, Fair value	1,671,471	1,352,413
Agencies
Investment [Line Items]
Fixed maturity investments trading, Fair value	96,208	186,050
Non-U.S. government (Sovereign Debt)
Investment [Line Items]
Fixed maturity investments trading, Fair value	280,651	334,580
Non-U.S. government-backed corporate
Investment [Line Items]
Fixed maturity investments trading, Fair value	146,467	237,479
Corporate
Investment [Line Items]
Fixed maturity investments trading, Fair value	1,610,442	1,803,415
Agency mortgage-backed
Investment [Line Items]
Fixed maturity investments trading, Fair value	312,333	336,661
Non-agency mortgage-backed
Investment [Line Items]
Fixed maturity investments trading, Fair value	241,590	243,795
Commercial mortgage-backed
Investment [Line Items]
Fixed maturity investments trading, Fair value	373,117	303,214
Asset-backed
Investment [Line Items]
Fixed maturity investments trading, Fair value	$24,406	$11,429

Investments_Schedule_of_Fair_V1

Investments (Schedule of Fair Value of Fixed Maturity Investments Available for Sale) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investment [Line Items]
Fixed maturity investments available-for-sale, Amortized cost	$23,772	$30,273
Fixed maturity investments available-for-sale, Fair value	26,885	34,241
Fixed maturity investments
Investment [Line Items]
Fixed maturity investments available-for-sale, Amortized cost	23,772	30,273
Gross Unrealized Gains	3,116	3,985
Gross Unrealized Losses	-3	-17
Fixed maturity investments available-for-sale, Fair value	26,885	34,241
Non-Credit Other-Than-Temporary Impairments	656	-742
Agency mortgage-backed
Investment [Line Items]
Fixed maturity investments available-for-sale, Amortized cost	3,928	4,880
Gross Unrealized Gains	359	378
Gross Unrealized Losses	0	-11
Fixed maturity investments available-for-sale, Fair value	4,287	5,247
Non-Credit Other-Than-Temporary Impairments	0	0
Non-agency mortgage-backed
Investment [Line Items]
Fixed maturity investments available-for-sale, Amortized cost	9,478	11,735
Gross Unrealized Gains	1,985	2,414
Gross Unrealized Losses	-3	-6
Fixed maturity investments available-for-sale, Fair value	11,460	14,143
Non-Credit Other-Than-Temporary Impairments	656	-742
Commercial mortgage-backed
Investment [Line Items]
Fixed maturity investments available-for-sale, Amortized cost	7,291	10,052
Gross Unrealized Gains	643	970
Gross Unrealized Losses	0	0
Fixed maturity investments available-for-sale, Fair value	7,934	11,022
Non-Credit Other-Than-Temporary Impairments	0	0
Asset-backed
Investment [Line Items]
Fixed maturity investments available-for-sale, Amortized cost	3,075	3,606
Gross Unrealized Gains	129	223
Gross Unrealized Losses	0	0
Fixed maturity investments available-for-sale, Fair value	3,204	3,829
Non-Credit Other-Than-Temporary Impairments	$0	$0

Investments_Schedule_of_Contra

Investments (Schedule of Contractual Maturities of Fixed Maturity Investments) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Trading Securities [Abstract]
Fixed maturity investments trading, Due in less than one year, Amortized cost	$153,250
Fixed maturity investments trading, Due after one through five years, Amortized cost	2,976,602
Fixed maturity investments trading, Due after five through ten years, Amortized cost	544,285
Fixed maturity investments trading, Due after ten years, Amortized cost	140,294
Fixed maturity investments trading, Amortized cost	4,749,613	4,781,712
Fixed maturity investments trading, Due in less than one year, Fair value	151,803
Fixed maturity investments trading, Due after one through five years, Fair value	2,969,828
Fixed maturity investments trading, Due after five through ten years, Fair value	537,636
Fixed maturity investments trading, Due after ten years, Fair value	145,972
Fixed maturity investments trading, Fair value	4,756,685
Available-for-sale Securities [Abstract]
Fixed maturity investments available-for-sale, Due in less than one year, Amortized Cost	0
Fixed maturity investments available-for-sale, Due after one through five years, Amortized cost	0
Fixed maturity investments available-for-sale, Due after five through ten years, Amortized cost	0
Fixed maturity investments available-for-sale, Due after ten years, Amortized cost	0
Fixed maturity investments available-for-sale, Amortized cost	23,772	30,273
Fixed maturity investments available-for-sale, Due in less than one year, Fair value	0
Fixed maturity investments available-for-sale, Due after one through five years, Fair value	0
Fixed maturity investments available-for-sale, Due after five through ten years, Fair value	0
Fixed maturity investments available-for-sale, Due after ten years, Fair value	0
Fixed maturity investments available-for-sale, Fair value	26,885	34,241
Fixed Maturity Investments [Abstract]
Fixed maturity investments, Due in less than one year, Amortized cost	153,250
Fixed maturity investments, Due after one through five years, Amortized cost	2,976,602
Fixed maturity investments, Due after five through ten years, Amortized cost	544,285
Fixed maturity investments, Due after ten years, Amortized cost	140,294
Fixed maturity investments, Amortized cost	4,773,385
Fixed maturity investments, Due in less than one year, Fair value	151,803
Fixed maturity investments, Due after one through give years, Fair value	2,969,828
Fixed maturity investments, Due after five through ten years, Fair value	537,636
Fixed maturity investments, Due after ten years, Fair value	145,972
Fixed maturity investments, Fair value	4,783,570
Mortgage-backed
Trading Securities [Abstract]
Fixed maturity investments trading, Amortized cost	910,897
Fixed maturity investments trading, Fair value	927,040
Available-for-sale Securities [Abstract]
Fixed maturity investments available-for-sale, Amortized cost	20,697
Fixed maturity investments available-for-sale, Fair value	23,681
Fixed Maturity Investments [Abstract]
Fixed maturity investments, Amortized cost	931,594
Fixed maturity investments, Fair value	950,721
Asset-backed
Trading Securities [Abstract]
Fixed maturity investments trading, Amortized cost	24,285
Fixed maturity investments trading, Fair value	24,406
Available-for-sale Securities [Abstract]
Fixed maturity investments available-for-sale, Amortized cost	3,075
Fixed maturity investments available-for-sale, Fair value	3,204
Fixed Maturity Investments [Abstract]
Fixed maturity investments, Amortized cost	27,360
Fixed maturity investments, Fair value	$27,610

Investments_Schedule_of_Fair_V2

Investments (Schedule of Fair Value of Equity Investments Trading) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investment [Line Items]
Equity investments trading	$322,098	$254,776
Financials
Investment [Line Items]
Equity investments trading	222,190	152,905
Communications and technology
Investment [Line Items]
Equity investments trading	31,376	4,300
Industrial, utilities and energy
Investment [Line Items]
Equity investments trading	28,859	25,350
Consumer
Investment [Line Items]
Equity investments trading	19,522	44,115
Healthcare
Investment [Line Items]
Equity investments trading	16,582	15,340
Basic materials
Investment [Line Items]
Equity investments trading	$3,569	$12,766

Investments_Schedule_of_Net_In

Investments (Schedule of Net Investment Income) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net Investment Income [Line Items]
Gross investment income									$135,655	$219,593	$177,531
Investment expenses									-11,339	-11,565	-11,806
Net investment income	25,886	24,941	34,541	38,948	78,732	59,931	26,163	43,202	124,316	208,028	165,725
Fixed maturity investments
Net Investment Income [Line Items]
Gross investment income									100,855	95,907	103,330
Short term investments
Net Investment Income [Line Items]
Gross investment income									944	1,698	1,007
Equity investments
Net Investment Income [Line Items]
Gross investment income									3,450	2,295	1,086
Other investments, Hedge funds and private equity investments
Net Investment Income [Line Items]
Gross investment income									18,867	45,810	36,635
Other investments, Other
Net Investment Income [Line Items]
Gross investment income									11,144	73,692	35,196
Cash and cash equivalents
Net Investment Income [Line Items]
Gross investment income									$395	$191	$277

Investments_Schedule_of_Net_Re

Investments (Schedule of Net Realized and Unrealized Gains on Investments and Net Other-Than-Temporary Impairments) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Gain (Loss) on Investments [Line Items]
Net realized and unrealized gains on investments	$30,475	($31,097)	$27,128	$14,927	$61,864	$28,472	($69,529)	$14,269	$41,433	$35,076	$163,121
Total other-than-temporary impairments									0	0	-395
Portion recognized in other comprehensive income (loss), before taxes									0	0	52
Net other-than-temporary impairments recognized in earnings									0	0	-343
Fixed maturity investments
Gain (Loss) on Investments [Line Items]
Gross realized gains									45,568	72,492	97,787
Gross realized losses									-14,868	-50,206	-16,705
Net realized gains on fixed maturity investments									30,700	22,286	81,082
Net unrealized gains (losses) on fixed maturity investments trading									19,680	-87,827	75,279
Investments-related derivatives
Gain (Loss) on Investments [Line Items]
Net realized and unrealized (losses) gains on investments-related derivatives									-30,931	31,058	-866
Equity investments
Gain (Loss) on Investments [Line Items]
Net unrealized gains (losses) on fixed maturity investments trading									11,076	42,909	7,626
Net realized gains on equity investments trading									$10,908	$26,650	$0

Investments_Schedule_of_Compon

Investments (Schedule of Components of Other Comprehensive Income and Reclassification Out of Accumulated Other Comprehensive Income) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$4,131	$13,622
Other comprehensive (loss) income before reclassifications	-715	-1,943
Realized gains reclassified from accumulated other comprehensive income to net realized and unrealized gains (losses) on investments	0	-7,548
Net current-period other comprehensive income (loss)	-715	-9,491
Ending balance	3,416	4,131
Investments in other ventures
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	163	1,625
Other comprehensive (loss) income before reclassifications	140	-1,462
Realized gains reclassified from accumulated other comprehensive income to net realized and unrealized gains (losses) on investments	0	0
Net current-period other comprehensive income (loss)	140	-1,462
Ending balance	303	163
Fixed maturity investments available for sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	3,968	11,997
Other comprehensive (loss) income before reclassifications	-855	-481
Realized gains reclassified from accumulated other comprehensive income to net realized and unrealized gains (losses) on investments	0	-7,548
Net current-period other comprehensive income (loss)	-855	-8,029
Ending balance	$3,113	$3,968

Investments_Schedule_of_Fixed_

Investments (Schedule of Fixed Maturity Investments Available For Sale In Continual Unrealized Loss Position) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	securities	securities
Schedule of Available-for-sale Securities [Line Items]
Number of fixed maturity investments available for sale securities in an unrealized loss position	2	4
Number of fixed maturity investments available for sale securities in an unrealized loss position for twelve months or greater	2	2
Fixed maturity investments
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	765
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	11
12 Months or Greater, Fair Value	69	89
12 Months of Greater, Unrealized Losses	-3	-6
Total, Fair Value	69	854
Total, Unrealized Loss	3	17
Agency mortgage-backed
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value		726
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		11
12 Months or Greater, Fair Value		0
12 Months of Greater, Unrealized Losses		0
Total, Fair Value		726
Total, Unrealized Loss		11
Non-agency mortgage-backed
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
12 Months or Greater, Fair Value	69	89
12 Months of Greater, Unrealized Losses	-3	-6
Total, Fair Value	69	89
Total, Unrealized Loss	3	6
Commercial mortgage-backed
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value		39
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0
12 Months or Greater, Fair Value		0
12 Months of Greater, Unrealized Losses		0
Total, Fair Value		39
Total, Unrealized Loss		0

Investments_Rollforward_of_The

Investments (Rollforward of The Amount of Other-Than-Temporary Impairments Related to Credit Losses Recognized in Earnings for Which a Portion of an Other-Than-Temporary Impairment was Recognized in Accumulated Other Comprehensive Income) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Investments [Abstract]
Portion of other-than-temporary impairments recognized in other comprehensive income (loss), before taxes	$0	$0	$52
Net other-than-temporary impairments recognized in earnings	0	0	-343
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning	561	838
Additions:
Amount related to credit loss for which an other-than-temporary impairment was not previously recognized	0	0
Amount related to credit loss for which an other-than-temporary impairment was previously recognized	0	0
Reductions:
Securities sold during the period	-63	-277
Securities for which the amount previously recognized in other comprehensive income was recognized in earnings, because the Company intends to sell the security or is more likely than not the Company will be required to sell the security	0	0
Increases in cash flows expected to be collected that are recognized over the remaining life of the security	0	0
Balance, ending	$498	$561	$838

Investments_Schedule_of_Other_

Investments (Schedule of Other Investments) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Other investments	$504,147,000				$573,264,000				$504,147,000	$573,264,000
Net investment income	25,886,000	24,941,000	34,541,000	38,948,000	78,732,000	59,931,000	26,163,000	43,202,000	124,316,000	208,028,000	165,725,000
Net unrealized gains (losses) recognized in earnings									-1,393,000	75,789,000	38,207,000
Initial commitments	623,800,000								623,800,000
Fulfilled commitments	544,100,000								544,100,000
Unfunded commitments	84,000,000								84,000,000
Other Investments
Schedule of Investments [Line Items]
Net investment income									30,000,000	119,500,000	71,800,000
Net investment income | Other Investments
Schedule of Investments [Line Items]
Net unrealized gains (losses) recognized in earnings									-1,400,000	75,800,000	38,200,000
Private equity partnerships
Schedule of Investments [Line Items]
Other investments					322,391,000					322,391,000
Catastrophe bonds
Schedule of Investments [Line Items]
Other investments					229,016,000					229,016,000
Senior secured bank loan funds
Schedule of Investments [Line Items]
Other investments					18,048,000					18,048,000
Hedge funds
Schedule of Investments [Line Items]
Other investments					3,809,000					3,809,000
Change in estimate of fair value | Other Investments
Schedule of Investments [Line Items]
Net investment income									-600,000	-3,700,000	-4,700,000
Private equity partnerships
Schedule of Investments [Line Items]
Other investments	281,932,000				322,391,000				281,932,000	322,391,000
Catastrophe bonds
Schedule of Investments [Line Items]
Other investments	200,329,000				229,016,000				200,329,000	229,016,000
Senior secured bank loan funds
Schedule of Investments [Line Items]
Other investments	19,316,000				18,048,000				19,316,000	18,048,000
Hedge funds
Schedule of Investments [Line Items]
Other investments	$2,570,000				$3,809,000				$2,570,000	$3,809,000

Investments_Schedule_of_Invest

Investments (Schedule of Investments in Other Ventures, under Equity Method) (Details) (USD $)	12 Months Ended			0 Months Ended	1 Months Ended			0 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 01, 2008	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010	Dec. 01, 2013	Jan. 06, 1999	Sep. 30, 2013
Schedule of Equity Method Investments [Line Items]
Investment	$143,632	$139,382
Investments in other ventures, under equity method	120,713	105,616
Equity method investee, additional contribution	-1,030	4,000	0
Tower Hill Companies
Schedule of Equity Method Investments [Line Items]
Investment	64,750	60,500
Investments in other ventures, under equity method	50,656	42,128
THIG
Schedule of Equity Method Investments [Line Items]
Investment	50,000	50,000		50,000
Ownership %	25.00%	25.00%		25.00%
Investments in other ventures, under equity method	20,811	25,107
Intangible Assets, Net				40,000
Goodwill				7,800
Tower Hill
Schedule of Equity Method Investments [Line Items]
Investment	10,000	10,000
Ownership %	30.30%	29.40%
Investments in other ventures, under equity method	18,991	14,506
Tower Hill Re
Schedule of Equity Method Investments [Line Items]
Investment	4,250	0
Ownership %	25.00%	0.00%
Investments in other ventures, under equity method	5,162	0
Tower Hill Signature
Schedule of Equity Method Investments [Line Items]
Investment	500	500
Ownership %	25.00%	25.00%
Investments in other ventures, under equity method	5,692	2,515
Top Layer Re
Schedule of Equity Method Investments [Line Items]
Investment	65,375	65,375							13,100
Ownership %	50.00%	50.00%							50.00%
Investments in other ventures, under equity method	60,911	50,500
Equity method investee, additional contribution					18,000	20,500	13,800
Angus
Schedule of Equity Method Investments [Line Items]
Investment	10,507	10,507
Ownership %	40.40%	42.50%						42.50%		38.80%
Investments in other ventures, under equity method	8,072	9,180
Goodwill								1,700
Other
Schedule of Equity Method Investments [Line Items]
Investment	3,000	3,000
Ownership %	22.00%	22.00%
Investments in other ventures, under equity method	$1,074	$3,808

Investments_Schedule_of_Equity

Investments (Schedule of Equity In (Losses) Earnings Of Other Ventures, Under Equity Method) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Equity in earnings of other ventures	$4,838,000	$9,806,000	$7,232,000	$4,199,000	$6,274,000	$7,313,000	$3,772,000	$5,835,000	$26,075,000	$23,194,000	$23,238,000
Undistributed earnings (losses) from equity method investments	20,000,000				15,500,000				20,000,000	15,500,000
Equity method investment, dividends or distributions									10,300,000	9,900,000	9,900,000
Tower Hill Companies
Schedule of Equity Method Investments [Line Items]
Equity in earnings of other ventures									18,376,000	10,270,000	4,965,000
Top Layer Re
Schedule of Equity Method Investments [Line Items]
Equity in earnings of other ventures									10,411,000	13,836,000	20,792,000
Angus
Schedule of Equity Method Investments [Line Items]
Equity in earnings of other ventures									-1,402,000	-858,000	-2,519,000
Other
Schedule of Equity Method Investments [Line Items]
Equity in earnings of other ventures									($1,310,000)	($54,000)	$0

Fair_Value_Measurements_Narrat

Fair Value Measurements (Narrative) (Details) (USD $)	12 Months Ended			0 Months Ended		3 Months Ended
Share data in Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 17, 2010	Oct. 31, 2013	Dec. 31, 2014	Sep. 30, 2013	Jun. 30, 2014	Jul. 18, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value transfers out of level 3	$24,644,000	$85,555,000
Total other assets and (liabilities)	-13,908,000	-8,233,000				-13,908,000
Net unrealized gains (losses) recognized in earnings	-1,393,000	75,789,000	38,207,000
Other Investments | Net investment income
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net unrealized gains (losses) recognized in earnings	-1,400,000	75,800,000	38,200,000
Other Assets and Liabilities | Other income (loss)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net unrealized gains (losses) recognized in earnings	0	0	-3,200,000
5.75% Senior Notes Due March 15, 2020 | RenRe North America Holdings Inc.
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
5.75% Senior Notes Due March 15, 2020				250,000,000
Senior notes interest rate				5.75%
Debt instrument maturity date				15-Mar-20
Senior Notes, fair value	279,000,000	273,900,000				279,000,000
Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total other assets and (liabilities)	-569,000	823,000				-569,000
Significant Other Observable Inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total other assets and (liabilities)	-4,405,000	-6,566,000				-4,405,000
Significant Other Observable Inputs (Level 2) | Cash Settled Restricted Stock Unit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total other assets and (liabilities)	-11,500,000					-11,500,000
Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	310,544,000					310,544,000
Total other assets and (liabilities)	-8,934,000	-2,490,000				-8,934,000
U.S. treasuries
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	1.00%	0.80%				1.00%
Agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	1.20%	1.30%				1.20%
Non-U.S. government (Sovereign Debt)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	1.10%	1.30%				1.10%
Non-U.S. government-backed corporate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	1.10%	1.10%				1.10%
Corporate
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	3.20%	2.70%				3.20%
Agency mortgage-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	2.30%	2.90%				2.30%
Weighted average life	5 years 7 months 6 days	6 years 2 months 12 days
Non-agency prime residential mortgage-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	3.40%	3.70%				3.40%
Weighted average life	4 years 1 month 6 days	4 years 4 months 24 days
AltA non-agency mortgage-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	4.30%	4.70%				4.30%
Weighted average life	5 years	4 years
Commercial mortgage-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	2.10%	2.10%				2.10%
Weighted average life	3 years 6 months 0 days	3 years 3 months 18 days
Asset-backed
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Weighted average effective yield	1.50%	2.00%				1.50%
Weighted average life	2 years 6 months	3 years 6 months
Senior secured bank loan funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment in closed end fund	19,300,000					19,300,000
Hedge funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Hedge fund side pocket investments	2,600,000					2,600,000
Fixed maturity investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value transfers out of level 3	24,644,000	0
Fixed maturity investments | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	15,660,000					15,660,000
Miscellaneous Investments | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3) | Essent Group Ltd.
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value							48,000,000
Trading Securities | Quoted Prices In Active Markets For Identical Assets (Level 1) | Essent Group Ltd.
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value transfers out of level 3					85,600,000
Equity investment, price per share					$17
Corporate | Discounted Cash Flow Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	15,700,000					15,700,000
Private equity partnerships | Net Asset Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	281,900,000					281,900,000
Assumed And Ceded Re Insurance Contracts Member | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total other assets and (liabilities)	-8,744,000					-8,744,000
Liabilities, fair value	8,700,000					8,700,000
Weather Contract | Internal Valuation Model Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liabilities, fair value	200,000					200,000
Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value transfers out of level 3	0	85,555,000
Other Investments | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	303,818,000					303,818,000
Weighted Average or Actual | Corporate | Discounted Cash Flow Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Dividend rate	6.50%
Liquidity discount	1.00%
Risk-free rate	0.50%
Credit spread	0.80%
Weighted Average or Actual | Private equity partnerships | Net Asset Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated performance						0.10%
Minimum | Private equity partnerships
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liquidating period	7 years
Minimum | Senior secured bank loan funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liquidating period	4 years
Minimum | Private equity partnerships | Net Asset Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated performance						-42.10%
Maximum | Private equity partnerships
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liquidating period	10 years
Maximum | Senior secured bank loan funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liquidating period	5 years
Maximum | Private equity partnerships | Net Asset Valuation Technique | Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated performance						17.00%
Convertible preferred stock | Trupanion
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity investment, fair value								30,200,000
Common stock | Trupanion
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity investment, fair value	17,100,000					17,100,000			24,600,000
Equity investment, number of shares									2.5
Equity investment, price per share									$10
Common stock | Essent Group Ltd.
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity investment, fair value	$120,000,000					120,000,000

Fair_Value_Measurements_Assets

Fair Value Measurements (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	$4,783,570	$4,843,277
Short-term investments	1,013,222	1,044,779
Equity investments trading	322,098	254,776
Other investments	504,147	573,264
Total other assets and (liabilities)	-13,908	-8,233
Total assets and liabilities measured on recurring basis	6,609,129	6,707,863
Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	1,671,471	1,352,413
Short-term investments	0	0
Equity investments trading	322,098	254,776
Other investments	0	0
Total other assets and (liabilities)	-569	823
Total assets and liabilities measured on recurring basis	1,993,000	1,608,012
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	3,096,439	3,463,284
Short-term investments	1,013,222	1,044,779
Equity investments trading	0	0
Other investments	200,329	229,016
Total other assets and (liabilities)	-4,405	-6,566
Total assets and liabilities measured on recurring basis	4,305,585	4,730,513
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	15,660	27,580
Short-term investments	0	0
Equity investments trading	0	0
Other investments	303,818	344,248
Total other assets and (liabilities)	-8,934	-2,490
Total assets and liabilities measured on recurring basis	310,544	369,338
U.S. treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	1,671,471	1,352,413
U.S. treasuries | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	1,671,471	1,352,413
U.S. treasuries | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
U.S. treasuries | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	96,208	186,050
Agencies | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Agencies | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	96,208	186,050
Agencies | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Non-U.S. government (Sovereign Debt)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	280,651	334,580
Non-U.S. government (Sovereign Debt) | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Non-U.S. government (Sovereign Debt) | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	280,651	334,580
Non-U.S. government (Sovereign Debt) | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Non-U.S. government-backed corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	146,467	237,479
Non-U.S. government-backed corporate | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Non-U.S. government-backed corporate | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	146,467	237,479
Non-U.S. government-backed corporate | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	1,610,442	1,803,415
Corporate | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Corporate | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	1,594,782	1,775,835
Corporate | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	15,660	27,580
Agency mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	316,620	341,908
Agency mortgage-backed | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Agency mortgage-backed | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	316,620	341,908
Agency mortgage-backed | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Non-agency mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	253,050	257,938
Non-agency mortgage-backed | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Non-agency mortgage-backed | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	253,050	257,938
Non-agency mortgage-backed | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	381,051	314,236
Commercial mortgage-backed | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Commercial mortgage-backed | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	381,051	314,236
Commercial mortgage-backed | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	27,610	15,258
Asset-backed | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Asset-backed | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	27,610	15,258
Asset-backed | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity investments	0	0
Private equity partnerships
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	281,932	322,391
Private equity partnerships | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Private equity partnerships | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Private equity partnerships | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	281,932	322,391
Catastrophe bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	200,329	229,016
Catastrophe bonds | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Catastrophe bonds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	200,329	229,016
Catastrophe bonds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Senior secured bank loan funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	19,316	18,048
Senior secured bank loan funds | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Senior secured bank loan funds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Senior secured bank loan funds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	19,316	18,048
Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	2,570	3,809
Hedge funds | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Hedge funds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Hedge funds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	2,570	3,809
Assumed and ceded reinsurance contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets and (liabilities)	-8,744
Assumed and ceded reinsurance contracts | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets and (liabilities)	0
Assumed and ceded reinsurance contracts | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets and (liabilities)	0
Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets and (liabilities)	6,345	4,758
Derivatives | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets and (liabilities)	-569	823
Derivatives | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets and (liabilities)	7,104	6,425
Derivatives | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets and (liabilities)	-190	-2,490
Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets and (liabilities)	-11,509	-12,991
Other | Quoted Prices In Active Markets For Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets and (liabilities)	0	0
Other | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets and (liabilities)	-11,509	-12,991
Other | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total other assets and (liabilities)	$0	$0

Fair_Value_Measurements_Quanti

Fair Value Measurements (Quantitative Information Used As Level 3 Inputs) (Details) (USD $)	12 Months Ended	3 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Total other assets and (liabilities)	-13,908,000	-13,908,000	($8,233,000)
Significant Unobservable Inputs (Level 3)
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets, fair value	310,544,000	310,544,000
Total other assets and (liabilities)	-8,934,000	-8,934,000	-2,490,000
Significant Unobservable Inputs (Level 3) | Private equity partnerships | Net Asset Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets, fair value	281,932,000	281,932,000
Significant Unobservable Inputs (Level 3) | Senior secured bank loan funds | Net Asset Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets, fair value	19,316,000	19,316,000
Significant Unobservable Inputs (Level 3) | Hedge funds | Net Asset Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets, fair value	2,570,000	2,570,000
Significant Unobservable Inputs (Level 3) | Corporate | Discounted Cash Flow Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets, fair value	15,700,000	15,700,000
Significant Unobservable Inputs (Level 3) | Corporate | Discounted Cash Flow Valuation Technique | Weighted Average or Actual
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Credit spread	0.80%
Liquidity discount	1.00%
Risk-free rate	0.50%
Dividend rate	6.50%
Significant Unobservable Inputs (Level 3) | Fixed maturity investments
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets, fair value	15,660,000	15,660,000
Significant Unobservable Inputs (Level 3) | Private equity partnerships | Net Asset Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets, fair value	281,900,000	281,900,000
Significant Unobservable Inputs (Level 3) | Private equity partnerships | Net Asset Valuation Technique | Low
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Estimated performance		-42.10%
Significant Unobservable Inputs (Level 3) | Private equity partnerships | Net Asset Valuation Technique | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Estimated performance		17.00%
Significant Unobservable Inputs (Level 3) | Private equity partnerships | Net Asset Valuation Technique | Weighted Average or Actual
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Estimated performance		0.10%
Significant Unobservable Inputs (Level 3) | Senior secured bank loan funds | Net Asset Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets, fair value	19,300,000	19,300,000
Significant Unobservable Inputs (Level 3) | Senior secured bank loan funds | Net Asset Valuation Technique | Weighted Average or Actual
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Estimated performance		0.80%
Significant Unobservable Inputs (Level 3) | Hedge funds | Net Asset Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets, fair value	2,570,000	2,570,000
Significant Unobservable Inputs (Level 3) | Hedge funds | Net Asset Valuation Technique | Low
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Estimated performance		0.00%
Significant Unobservable Inputs (Level 3) | Hedge funds | Net Asset Valuation Technique | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Estimated performance		0.00%
Significant Unobservable Inputs (Level 3) | Hedge funds | Net Asset Valuation Technique | Weighted Average or Actual
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Estimated performance		0.00%
Significant Unobservable Inputs (Level 3) | Other investments
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets, fair value	303,818,000	303,818,000
Significant Unobservable Inputs (Level 3) | Assumed And Ceded Re Insurance Contracts Member | Internal Valuation Model Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Liabilities, fair value	-8,700,000	-8,700,000
Total other assets and (liabilities)	-8,744,000	-8,744,000
Significant Unobservable Inputs (Level 3) | Assumed And Ceded Re Insurance Contracts Member | Internal Valuation Model Valuation Technique | Low
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net undiscounted cash flows	160,000
Contract period	549	549
Significant Unobservable Inputs (Level 3) | Assumed And Ceded Re Insurance Contracts Member | Internal Valuation Model Valuation Technique | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net undiscounted cash flows	8,006,000
Contract period	1,100	1,100
Significant Unobservable Inputs (Level 3) | Assumed And Ceded Re Insurance Contracts Member | Internal Valuation Model Valuation Technique | Weighted Average or Actual
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net undiscounted cash flows	2,528,000
Contract period	832	832
Discount rate	1.10%
Significant Unobservable Inputs (Level 3) | Weather Contract | Internal Valuation Model Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Liabilities, fair value	-200,000	-200,000

Fair_Value_Measurements_Assets1

Fair Value Measurements (Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Level 3 Inputs) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of the period	$369,338	$430,372
Total unrealized gains (losses)
Included in net investment income	15,224	81,070
Included in other loss		-625
Total realized gains (losses)
Included in net investment income		-4,114
Included in other loss	1,262	-2,083
Total foreign exchange gains (losses)	-3,300	1,352
Purchases	33,990	46,565
Settlements	-81,326	-97,644
Reclassified from other assets to other investments		0
Net transfers out of Level 3	-24,644	-85,555
Balance at end of the period	310,544	369,338
Fixed maturity investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of the period	27,580	27,792
Total unrealized gains (losses)
Included in net investment income	12,724	2,288
Included in other loss		0
Total realized gains (losses)
Included in net investment income		0
Included in other loss	0	0
Total foreign exchange gains (losses)	0	0
Purchases	0	0
Settlements	0	-2,500
Reclassified from other assets to other investments		0
Net transfers out of Level 3	-24,644	0
Balance at end of the period	15,660	27,580
Other Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of the period	344,248	381,067
Total unrealized gains (losses)
Included in net investment income	1,045	80,113
Included in other loss		0
Total realized gains (losses)
Included in net investment income		-4,114
Included in other loss	0	0
Total foreign exchange gains (losses)	-3,279	1,352
Purchases	43,130	48,287
Settlements	-81,326	-95,144
Reclassified from other assets to other investments		18,242
Net transfers out of Level 3	0	-85,555
Balance at end of the period	303,818	344,248
Other Assets and Liabilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of the period	-2,490	21,513
Total unrealized gains (losses)
Included in net investment income	1,455	-1,331
Included in other loss		-625
Total realized gains (losses)
Included in net investment income		0
Included in other loss	1,262	-2,083
Total foreign exchange gains (losses)	-21	0
Purchases	-9,140	-1,722
Settlements	0	0
Reclassified from other assets to other investments		-18,242
Net transfers out of Level 3	0	0
Balance at end of the period	-8,934	-2,490
Net investment income
Total realized gains (losses)
Change in unrealized gains for the period included in earnings for assets held at the end of the period	2,434	79,860
Net investment income | Fixed maturity investments
Total realized gains (losses)
Change in unrealized gains for the period included in earnings for assets held at the end of the period	-66	2,288
Net investment income | Other Investments
Total realized gains (losses)
Change in unrealized gains for the period included in earnings for assets held at the end of the period	1,045	78,903
Net investment income | Other Assets and Liabilities
Total realized gains (losses)
Change in unrealized gains for the period included in earnings for assets held at the end of the period	$1,455	($1,331)

Fair_Value_Measurements_Summar

Fair Value Measurements (Summary Of The Balances Company Has Elected To Account For At Fair Value) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value Disclosures [Abstract]
Other investments	$504,147	$573,264
Other assets (liabilities)	($8,744)	$0

Fair_Value_Measurements_Compan

Fair Value Measurements (Company's Portfolio of Other Investments Measured Using Net Asset Valuations) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$303,818
Unfunded Commitments	84,013
Private equity partnerships
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	281,932
Unfunded Commitments	77,712
Senior secured bank loan funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	19,316
Unfunded Commitments	6,301
Hedge funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	2,570
Unfunded Commitments	$0

Reinsurance_Effect_Of_Reinsura

Reinsurance (Effect Of Reinsurance And Retrocessional Activity On Premiums Written And Earned And On Net Claims And Claim Expenses) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Premiums written
Direct									$76,511	$54,334	$36,367
Assumed									1,474,061	1,551,078	1,515,224
Ceded									-482,336	-401,465	-448,934
Net premiums written	111,769	159,713	346,407	450,347	80,784	127,241	559,109	436,813	1,068,236	1,203,947	1,102,657
Premiums earned
Direct									66,027	44,530	34,028
Assumed									1,450,047	1,482,511	1,465,701
Ceded									-453,658	-412,415	-430,374
Net premiums earned (Note 7)	256,487	258,979	260,416	286,534	256,765	294,717	291,889	271,255	1,062,416	1,114,626	1,069,355
Claims and claim expenses
Gross claims and claim expenses incurred									228,581	185,139	403,491
Claims and claim expenses recovered									-30,634	-13,852	-78,280
Net claims and claim expenses incurred	($12,003)	$69,647	$81,388	$58,915	($20,854)	$60,928	$103,962	$27,251	$197,947	$171,287	$325,211

Reinsurance_Narrative_Details

Reinsurance (Narrative) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Reinsurance Recoverable | Largest reinsurance recoverable, Customer One
Concentration risk percentage	35.40%	28.20%
Reinsurance Recoverable | Largest reinsurance recoverable, Customer Two
Concentration risk percentage	14.90%	19.90%
Reinsurance Recoverable | Largest reinsurance recoverable, Customer Three
Concentration risk percentage	7.00%	11.00%
Allowance for Reinsurance Recoverable | Largest reinsurance recoverable, Customer One
Concentration risk percentage	17.90%	14.20%
Allowance for Reinsurance Recoverable | Largest reinsurance recoverable, Customer Two
Concentration risk percentage	4.00%	12.50%
Allowance for Reinsurance Recoverable | Largest reinsurance recoverable, Customer Three
Concentration risk percentage	2.90%	3.10%
Allowance for Reinsurance Recoverable
Valuation allowance recorded against reinsurance recoverable	1	1.7

Reserve_for_Claims_and_Claim_E2

Reserve for Claims and Claim Expenses (Narrative) (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 01, 2012
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	$143,798,000	$143,954,000	$157,969,000
Reinsurance Balances Payable
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Aggregate deposit liabilities	39,000,000	39,700,000
Aggregate deposit assets
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Aggregate deposit assets	0	0
Deposit Contracts, Underwriting Risk Only
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase (decrease) in net claims and claim expenses related to assumed reinsurance contracts	-300,000	-400,000	-100,000
Deposit Contracts, Timing Risk Only
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase (decrease) in other income related to assumed reinsurance contracts	-100,000	-100,000	-7,500,000
Catastrophe
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	92,366,000	111,496,000	124,215,000
Catastrophe | Large Catastrophe Event
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	65,537,000	94,527,000	76,390,000
Catastrophe | Hurricanes Katrina, Rita and Wilma (2005)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses			7,730,000
Catastrophe | Hurricanes Gustav and Ike (2008)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	6,647,000	16,665,000	20,467,000
Catastrophe | European Floods (2013)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	7,552,000
Catastrophe | Storm Sandy (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	24,232,000	48,285,000
Catastrophe | Tohoku Earthquake and Tsunami (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	5,131,000	19,033,000	3,896,000
Catastrophe | New Zealand Earthquake (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		10,944,000	-17,912,000
Catastrophe | New Zealand Earthquake (2010)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	-24,692,000	-11,340,000	-3,570,000
Catastrophe | U.S. PCS 70 and 73 Wind and Thunderstorm (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	-13,362,000
Catastrophe | Hurricane Isaac (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		-2,610,000
Catastrophe | Thailand Floods (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	11,754,000		9,433,000
Catastrophe | Hurricane Irene (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	4,506,000		7,130,000
Catastrophe | Other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	13,704,000	5,306,000	3,953,000
Catastrophe | Small Catastrophe Event
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	26,829,000	16,969,000	47,825,000
Catastrophe | U.S. PCS 70 Wind and Thunderstorm (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		-8,225,000
Catastrophe | April and May U.S. Tornadoes 2011
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	13,939,000
Catastrophe | U.S. PCS 24 Wind and Thunderstorm (2013)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	6,712,000
Catastrophe | LIBOR (2011 and 2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	11,750,000
Catastrophe | Subprime (2007)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	-5,049,000
Actuarial Assumption Changes
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		10,158,000	13,114,000
Actual Reported Claims Less than Expected Claims
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	51,432,000	22,300,000	20,640,000
Attritional Claims and Claim Expenses
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	51,432,000	32,458,000	33,754,000
Catastrophe Reinsurance
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	65,511,000	102,037,000	110,568,000
Catastrophe Reinsurance | Catastrophe
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	65,511,000	102,037,000	110,568,000
Catastrophe Reinsurance | Catastrophe | Large Catastrophe Event
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	47,506,000	85,068,000	62,743,000
Catastrophe Reinsurance | Catastrophe | Hurricanes Katrina, Rita and Wilma (2005)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Initial estimated ultimate claim	1,300,000,000
Liability for unpaid claims and claim expenses			6,420,000
Catastrophe Reinsurance | Catastrophe | Hurricanes Gustav and Ike (2008)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Initial estimated ultimate claim	530,000,000
Liability for unpaid claims and claim expenses	6,647,000	16,261,000	17,541,000
Catastrophe Reinsurance | Catastrophe | New Zealand Earthquake, Tohoku Earthquake, United States Tornadoes, Australian Floods, Hurricane Irene, Thailand Floods
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Initial estimated ultimate claim	1,100,000,000
Catastrophe Reinsurance | Catastrophe | European Floods (2013)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	7,552,000
Catastrophe Reinsurance | Catastrophe | Storm Sandy (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	20,104,000	44,460,000
Catastrophe Reinsurance | Catastrophe | Tohoku Earthquake and Tsunami (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	3,489,000	18,033,000	3,896,000
Catastrophe Reinsurance | Catastrophe | New Zealand Earthquake (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		10,944,000	-17,912,000
Catastrophe Reinsurance | Catastrophe | New Zealand Earthquake (2010)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	-24,692,000	-11,040,000	-3,570,000
Catastrophe Reinsurance | Catastrophe | U.S. PCS 70 and 73 Wind and Thunderstorm (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	-13,362,000
Catastrophe Reinsurance | Catastrophe | Hurricane Isaac (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		-2,610,000
Catastrophe Reinsurance | Catastrophe | Thailand Floods (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	9,254,000		3,933,000
Catastrophe Reinsurance | Catastrophe | Hurricane Irene (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	4,506,000		4,630,000
Catastrophe Reinsurance | Catastrophe | Other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	10,644,000	776,000	2,542,000
Catastrophe Reinsurance | Catastrophe | Small Catastrophe Event
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	18,005,000	16,969,000	47,825,000
Catastrophe Reinsurance | Catastrophe | U.S. PCS 70 Wind and Thunderstorm (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		-8,225,000
Catastrophe Reinsurance | Catastrophe | April and May U.S. Tornadoes 2011
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	13,939,000
Catastrophe Reinsurance | Catastrophe | U.S. PCS 24 Wind and Thunderstorm (2013)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	6,712,000
Catastrophe Reinsurance | Catastrophe | LIBOR (2011 and 2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Catastrophe Reinsurance | Catastrophe | Subprime (2007)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Catastrophe Reinsurance | Catastrophe Claims and Claim Expense Excluding Certain Specific Events
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		-34,214,000	84,225,000
Catastrophe Reinsurance | Actuarial Assumption Changes
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		0	0
Catastrophe Reinsurance | Actual Reported Claims Less than Expected Claims
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	0	0
Catastrophe Reinsurance | Attritional Claims and Claim Expenses
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	0	0
Specialty Reinsurance
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	55,909,000	34,111,000	34,146,000
Specialty Reinsurance | Catastrophe
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	11,419,000	2,463,000	3,000,000
Specialty Reinsurance | Catastrophe | Large Catastrophe Event
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	11,419,000	2,463,000	3,000,000
Specialty Reinsurance | Catastrophe | Hurricanes Katrina, Rita and Wilma (2005)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses			3,000,000
Specialty Reinsurance | Catastrophe | Hurricanes Gustav and Ike (2008)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	0	0
Specialty Reinsurance | Catastrophe | European Floods (2013)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Specialty Reinsurance | Catastrophe | Storm Sandy (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	0
Specialty Reinsurance | Catastrophe | Tohoku Earthquake and Tsunami (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	1,642,000	1,000,000	0
Specialty Reinsurance | Catastrophe | New Zealand Earthquake (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		0	0
Specialty Reinsurance | Catastrophe | New Zealand Earthquake (2010)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	-300,000	0
Specialty Reinsurance | Catastrophe | U.S. PCS 70 and 73 Wind and Thunderstorm (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Specialty Reinsurance | Catastrophe | Hurricane Isaac (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		0
Specialty Reinsurance | Catastrophe | Thailand Floods (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	2,500,000		0
Specialty Reinsurance | Catastrophe | Hurricane Irene (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0		0
Specialty Reinsurance | Catastrophe | Other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	1,826,000	1,763,000	0
Specialty Reinsurance | Catastrophe | Small Catastrophe Event
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	0	0
Specialty Reinsurance | Catastrophe | U.S. PCS 70 Wind and Thunderstorm (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		0
Specialty Reinsurance | Catastrophe | April and May U.S. Tornadoes 2011
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Specialty Reinsurance | Catastrophe | U.S. PCS 24 Wind and Thunderstorm (2013)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Specialty Reinsurance | Catastrophe | LIBOR (2011 and 2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	10,500,000
Specialty Reinsurance | Catastrophe | Subprime (2007)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	-5,049,000
Specialty Reinsurance | Actuarial Assumption Changes
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		10,432,000	14,399,000
Specialty Reinsurance | Reported Claims Less than Expected Including Catastrophe Events
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		23,679,000
Specialty Reinsurance | Actual Reported Claims Less than Expected Claims
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	44,490,000	21,216,000	16,747,000
Specialty Reinsurance | Attritional Claims and Claim Expenses
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	44,490,000	31,648,000	31,146,000
Lloyd's
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	16,241,000	8,256,000	16,202,000
Lloyd's | Catastrophe
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	9,299,000	5,267,000	9,476,000
Lloyd's | Catastrophe | Large Catastrophe Event
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	6,612,000	5,267,000	9,476,000
Lloyd's | Catastrophe | Hurricanes Katrina, Rita and Wilma (2005)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses			0
Lloyd's | Catastrophe | Hurricanes Gustav and Ike (2008)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	0	0
Lloyd's | Catastrophe | European Floods (2013)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Lloyd's | Catastrophe | Storm Sandy (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	4,128,000	3,825,000
Lloyd's | Catastrophe | Tohoku Earthquake and Tsunami (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	0	0
Lloyd's | Catastrophe | New Zealand Earthquake (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		0	0
Lloyd's | Catastrophe | New Zealand Earthquake (2010)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	0	0
Lloyd's | Catastrophe | U.S. PCS 70 and 73 Wind and Thunderstorm (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Lloyd's | Catastrophe | Hurricane Isaac (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		0
Lloyd's | Catastrophe | Thailand Floods (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0		5,500,000
Lloyd's | Catastrophe | Hurricane Irene (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0		2,500,000
Lloyd's | Catastrophe | Other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	1,234,000	1,442,000	1,476,000
Lloyd's | Catastrophe | Small Catastrophe Event
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	2,687,000	0	0
Lloyd's | Catastrophe | U.S. PCS 70 Wind and Thunderstorm (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		0
Lloyd's | Catastrophe | April and May U.S. Tornadoes 2011
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Lloyd's | Catastrophe | U.S. PCS 24 Wind and Thunderstorm (2013)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Lloyd's | Catastrophe | LIBOR (2011 and 2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	1,250,000
Lloyd's | Catastrophe | Subprime (2007)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Lloyd's | Actuarial Assumption Changes
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		-274,000	-1,285,000
Lloyd's | Actuarial Assumption Changes | Other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses			1,300,000
Lloyd's | Actual Reported Claims Less than Expected Claims
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	6,942,000	3,263,000	8,011,000
Lloyd's | Attritional Claims and Claim Expenses
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	6,942,000	2,989,000	6,726,000
Other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	6,137,000	-450,000	-2,947,000
Other | Catastrophe
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	6,137,000	1,729,000	1,171,000
Other | Catastrophe | Large Catastrophe Event
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	1,729,000	1,171,000
Other | Catastrophe | Hurricanes Katrina, Rita and Wilma (2005)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses			-1,690,000
Other | Catastrophe | Hurricanes Gustav and Ike (2008)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	404,000	2,926,000
Other | Catastrophe | European Floods (2013)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Other | Catastrophe | Storm Sandy (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	0
Other | Catastrophe | Tohoku Earthquake and Tsunami (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	0	0
Other | Catastrophe | New Zealand Earthquake (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		0	0
Other | Catastrophe | New Zealand Earthquake (2010)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	0	0
Other | Catastrophe | U.S. PCS 70 and 73 Wind and Thunderstorm (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Other | Catastrophe | Hurricane Isaac (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		0
Other | Catastrophe | Thailand Floods (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0		0
Other | Catastrophe | Hurricane Irene (2011)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0		0
Other | Catastrophe | Other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	1,325,000	-65,000
Other | Catastrophe | Small Catastrophe Event
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	6,137,000	0	0
Other | Catastrophe | U.S. PCS 70 Wind and Thunderstorm (2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		0
Other | Catastrophe | April and May U.S. Tornadoes 2011
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Other | Catastrophe | U.S. PCS 24 Wind and Thunderstorm (2013)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Other | Catastrophe | LIBOR (2011 and 2012)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Other | Catastrophe | Subprime (2007)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0
Other | Actuarial Assumption Changes
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses		0	0
Other | Actual Reported Claims Less than Expected Claims
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	-2,179,000	-4,118,000
Other | Attritional Claims and Claim Expenses
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses	0	-2,179,000	-4,118,000
Other | Loss Portfolio Transfer, Cash Consideration Paid
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses				-36,500,000
Other | Loss Portfolio Transfer, Attritional Claims and Claim Expenses
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses				29,100,000
Other | Loss Portfolio Transfer, Loss Recognized
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for unpaid claims and claim expenses				($7,400,000)

Reserve_for_Claims_and_Claim_E3

Reserve for Claims and Claim Expenses (Schedule of Liability for Unpaid Claims and Claims Adjustment Expense) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Net reserves as of January 1	$1,462,705	$1,686,865	$1,588,325
Net incurred related to:
Current year	341,745	315,241	483,180
Prior years	-143,798	-143,954	-157,969
Total net incurred	197,947	171,287	325,211
Net paid related to:
Current year	39,830	32,212	84,056
Prior years	275,006	363,235	142,615
Total net paid	314,836	395,447	226,671
Net reserves as of December 31	1,345,816	1,462,705	1,686,865
Reinsurance recoverable as of December 31	66,694	101,025	192,512
Gross reserves as of December 31	1,412,510	1,563,730	1,879,377
Catastrophe Reinsurance
Net incurred related to:
Current year	67,268	109,945	275,777
Prior years	-65,511	-102,037	-110,568
Total net incurred	1,757	7,908	165,209
Specialty Reinsurance
Net incurred related to:
Current year	144,411	101,347	110,959
Prior years	-55,909	-34,111	-34,146
Total net incurred	88,502	67,236	76,813
Lloyd's
Net incurred related to:
Current year	130,066	103,949	96,444
Prior years	-16,241	-8,256	-16,202
Total net incurred	113,825	95,693	80,242
Other
Net incurred related to:
Current year	0	0	0
Prior years	-6,137	450	2,947
Total net incurred	($6,137)	$450	$2,947

Reserve_for_Claims_and_Claim_E4

Reserve for Claims and Claim Expenses (Liability for Catastrophe Claims) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Liability for Catastrophe Claims [Line Items]
Prior years	($143,798)	($143,954)	($157,969)
Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-92,366	-111,496	-124,215
Attritional Claims and Claim Expenses
Liability for Catastrophe Claims [Line Items]
Prior years	-51,432	-32,458	-33,754
Reported Claims Less than Expected
Liability for Catastrophe Claims [Line Items]
Prior years	-51,432	-22,300	-20,640
Actuarial Assumption Changes
Liability for Catastrophe Claims [Line Items]
Prior years		-10,158	-13,114
Large Catastrophe Event | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-65,537	-94,527	-76,390
Storm Sandy (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-24,232	-48,285
April and May U.S. Tornadoes 2011 | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-13,939
Thailand Floods (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-11,754		-9,433
LIBOR (2011 and 2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-11,750
Chile Earthquake (2010) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-24,575
Hurricanes Gustav and Ike (2008) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-6,647	-16,665	-20,467
U.K. Floods (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-17,271
Hurricanes Katrina, Rita and Wilma (2005) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-7,730
Tohoku Earthquake and Tsunami (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-5,131	-19,033	-3,896
Hurricane Irene (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-4,506		-7,130
New Zealand Earthquake (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		-10,944	17,912
Windstorm Kyrill (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-3,615	-8,244	-3,417
Subprime (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	5,049
Hurricane Isaac (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		2,610
New Zealand Earthquake (2010) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	24,692	11,340	3,570
Other | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-13,704	-5,306	-3,953
Small Catastrophe Event | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-26,829	-16,969	-47,825
European Floods (2013) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-7,552
U.S. PCS 24 Wind and Thunderstorm (2013) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-6,712
U.S. PCS 83 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		-3,500
U.S. PCS 76 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		-300
U.S. PCS 70 and 73 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	13,362
U.S. PCS 70 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		8,225
Danish Floods (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-5,000
U.S. PCS 63 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-5,000
U.S. PCS 42 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-2,560
U.S. PCS 53 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-2,558
Other | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-25,927	-21,394	-32,707
Catastrophe Reinsurance
Liability for Catastrophe Claims [Line Items]
Prior years	-65,511	-102,037	-110,568
Catastrophe Reinsurance | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-65,511	-102,037	-110,568
Catastrophe Reinsurance | Attritional Claims and Claim Expenses
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Catastrophe Reinsurance | Reported Claims Less than Expected
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Catastrophe Reinsurance | Actuarial Assumption Changes
Liability for Catastrophe Claims [Line Items]
Prior years		0	0
Catastrophe Reinsurance | Large Catastrophe Event | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-47,506	-85,068	-62,743
Catastrophe Reinsurance | Storm Sandy (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-20,104	-44,460
Catastrophe Reinsurance | April and May U.S. Tornadoes 2011 | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-13,939
Catastrophe Reinsurance | Thailand Floods (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-9,254		-3,933
Catastrophe Reinsurance | LIBOR (2011 and 2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Catastrophe Reinsurance | Chile Earthquake (2010) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-24,575
Catastrophe Reinsurance | Hurricanes Gustav and Ike (2008) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-6,647	-16,261	-17,541
Catastrophe Reinsurance | U.K. Floods (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-17,271
Catastrophe Reinsurance | Hurricanes Katrina, Rita and Wilma (2005) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-6,420
Catastrophe Reinsurance | Tohoku Earthquake and Tsunami (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-3,489	-18,033	-3,896
Catastrophe Reinsurance | Hurricane Irene (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-4,506		-4,630
Catastrophe Reinsurance | New Zealand Earthquake (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		-10,944	17,912
Catastrophe Reinsurance | Windstorm Kyrill (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-3,615	-8,244	-3,417
Catastrophe Reinsurance | Subprime (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Catastrophe Reinsurance | Hurricane Isaac (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		2,610
Catastrophe Reinsurance | New Zealand Earthquake (2010) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	24,692	11,040	3,570
Catastrophe Reinsurance | Other | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-10,644	-776	-2,542
Catastrophe Reinsurance | Small Catastrophe Event | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-18,005	-16,969	-47,825
Catastrophe Reinsurance | European Floods (2013) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-7,552
Catastrophe Reinsurance | U.S. PCS 24 Wind and Thunderstorm (2013) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-6,712
Catastrophe Reinsurance | U.S. PCS 83 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		-3,500
Catastrophe Reinsurance | U.S. PCS 76 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		-300
Catastrophe Reinsurance | U.S. PCS 70 and 73 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	13,362
Catastrophe Reinsurance | U.S. PCS 70 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		8,225
Catastrophe Reinsurance | Danish Floods (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-5,000
Catastrophe Reinsurance | U.S. PCS 63 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-5,000
Catastrophe Reinsurance | U.S. PCS 42 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-2,560
Catastrophe Reinsurance | U.S. PCS 53 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-2,558
Catastrophe Reinsurance | Other | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-17,103	-21,394	-32,707
Specialty Reinsurance
Liability for Catastrophe Claims [Line Items]
Prior years	-55,909	-34,111	-34,146
Specialty Reinsurance | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-11,419	-2,463	-3,000
Specialty Reinsurance | Attritional Claims and Claim Expenses
Liability for Catastrophe Claims [Line Items]
Prior years	-44,490	-31,648	-31,146
Specialty Reinsurance | Reported Claims Less than Expected
Liability for Catastrophe Claims [Line Items]
Prior years	-44,490	-21,216	-16,747
Specialty Reinsurance | Actuarial Assumption Changes
Liability for Catastrophe Claims [Line Items]
Prior years		-10,432	-14,399
Specialty Reinsurance | Large Catastrophe Event | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-11,419	-2,463	-3,000
Specialty Reinsurance | Storm Sandy (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0
Specialty Reinsurance | April and May U.S. Tornadoes 2011 | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Specialty Reinsurance | Thailand Floods (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-2,500		0
Specialty Reinsurance | LIBOR (2011 and 2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-10,500
Specialty Reinsurance | Chile Earthquake (2010) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Specialty Reinsurance | Hurricanes Gustav and Ike (2008) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Specialty Reinsurance | U.K. Floods (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Specialty Reinsurance | Hurricanes Katrina, Rita and Wilma (2005) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			-3,000
Specialty Reinsurance | Tohoku Earthquake and Tsunami (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-1,642	-1,000	0
Specialty Reinsurance | Hurricane Irene (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0		0
Specialty Reinsurance | New Zealand Earthquake (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0	0
Specialty Reinsurance | Windstorm Kyrill (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Specialty Reinsurance | Subprime (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	5,049
Specialty Reinsurance | Hurricane Isaac (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0
Specialty Reinsurance | New Zealand Earthquake (2010) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	300	0
Specialty Reinsurance | Other | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-1,826	-1,763	0
Specialty Reinsurance | Small Catastrophe Event | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Specialty Reinsurance | European Floods (2013) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Specialty Reinsurance | U.S. PCS 24 Wind and Thunderstorm (2013) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Specialty Reinsurance | U.S. PCS 83 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0
Specialty Reinsurance | U.S. PCS 76 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0
Specialty Reinsurance | U.S. PCS 70 and 73 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Specialty Reinsurance | U.S. PCS 70 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0
Specialty Reinsurance | Danish Floods (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Specialty Reinsurance | U.S. PCS 63 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Specialty Reinsurance | U.S. PCS 42 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Specialty Reinsurance | U.S. PCS 53 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Specialty Reinsurance | Other | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Lloyd's
Liability for Catastrophe Claims [Line Items]
Prior years	-16,241	-8,256	-16,202
Lloyd's | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-9,299	-5,267	-9,476
Lloyd's | Attritional Claims and Claim Expenses
Liability for Catastrophe Claims [Line Items]
Prior years	-6,942	-2,989	-6,726
Lloyd's | Reported Claims Less than Expected
Liability for Catastrophe Claims [Line Items]
Prior years	-6,942	-3,263	-8,011
Lloyd's | Actuarial Assumption Changes
Liability for Catastrophe Claims [Line Items]
Prior years		274	1,285
Lloyd's | Large Catastrophe Event | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-6,612	-5,267	-9,476
Lloyd's | Storm Sandy (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-4,128	-3,825
Lloyd's | April and May U.S. Tornadoes 2011 | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Lloyd's | Thailand Floods (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0		-5,500
Lloyd's | LIBOR (2011 and 2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-1,250
Lloyd's | Chile Earthquake (2010) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Lloyd's | Hurricanes Gustav and Ike (2008) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Lloyd's | U.K. Floods (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Lloyd's | Hurricanes Katrina, Rita and Wilma (2005) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Lloyd's | Tohoku Earthquake and Tsunami (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Lloyd's | Hurricane Irene (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0		-2,500
Lloyd's | New Zealand Earthquake (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0	0
Lloyd's | Windstorm Kyrill (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Lloyd's | Subprime (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Lloyd's | Hurricane Isaac (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0
Lloyd's | New Zealand Earthquake (2010) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Lloyd's | Other | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-1,234	-1,442	-1,476
Lloyd's | Other | Actuarial Assumption Changes
Liability for Catastrophe Claims [Line Items]
Prior years			-1,300
Lloyd's | Small Catastrophe Event | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-2,687	0	0
Lloyd's | European Floods (2013) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Lloyd's | U.S. PCS 24 Wind and Thunderstorm (2013) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Lloyd's | U.S. PCS 83 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0
Lloyd's | U.S. PCS 76 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0
Lloyd's | U.S. PCS 70 and 73 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Lloyd's | U.S. PCS 70 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0
Lloyd's | Danish Floods (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Lloyd's | U.S. PCS 63 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Lloyd's | U.S. PCS 42 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Lloyd's | U.S. PCS 53 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Lloyd's | Other | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-2,687	0	0
Other
Liability for Catastrophe Claims [Line Items]
Prior years	-6,137	450	2,947
Other | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-6,137	-1,729	-1,171
Other | Attritional Claims and Claim Expenses
Liability for Catastrophe Claims [Line Items]
Prior years	0	2,179	4,118
Other | Reported Claims Less than Expected
Liability for Catastrophe Claims [Line Items]
Prior years	0	2,179	4,118
Other | Actuarial Assumption Changes
Liability for Catastrophe Claims [Line Items]
Prior years		0	0
Other | Large Catastrophe Event | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	-1,729	-1,171
Other | Storm Sandy (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0
Other | April and May U.S. Tornadoes 2011 | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Other | Thailand Floods (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0		0
Other | LIBOR (2011 and 2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Other | Chile Earthquake (2010) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Other | Hurricanes Gustav and Ike (2008) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	-404	-2,926
Other | U.K. Floods (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Other | Hurricanes Katrina, Rita and Wilma (2005) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			1,690
Other | Tohoku Earthquake and Tsunami (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Other | Hurricane Irene (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0		0
Other | New Zealand Earthquake (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0	0
Other | Windstorm Kyrill (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Other | Subprime (2007) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Other | Hurricane Isaac (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0
Other | New Zealand Earthquake (2010) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	0	0
Other | Other | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0	-1,325	65
Other | Small Catastrophe Event | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	-6,137	0	0
Other | European Floods (2013) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Other | U.S. PCS 24 Wind and Thunderstorm (2013) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Other | U.S. PCS 83 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0
Other | U.S. PCS 76 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0
Other | U.S. PCS 70 and 73 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	0
Other | U.S. PCS 70 Wind and Thunderstorm (2012) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years		0
Other | Danish Floods (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Other | U.S. PCS 63 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Other | U.S. PCS 42 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Other | U.S. PCS 53 Winter Storm (2011) | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years			0
Other | Other | Catastrophe
Liability for Catastrophe Claims [Line Items]
Prior years	($6,137)	$0	$0

Debt_and_Credit_Facilities_Nar

Debt and Credit Facilities (Narrative) (Details)

12 Months Ended

12 Months Ended

0 Months Ended

0 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

Apr. 01, 2011

Mar. 17, 2010

Feb. 15, 2013

Jan. 31, 2003

Jan. 31, 2003

Dec. 31, 2014

23-May-13

17-May-12

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

Oct. 01, 2013

Oct. 01, 2013

Apr. 01, 2011

USD ($)

USD ($)

USD ($)

Letter of Credit

RenRe North America Holdings Inc.

RenRe North America Holdings Inc.

Syndicate 1458

Syndicate 1458

RenaissanceRe Specialty Risks

Top Layer Re

Top Layer Re

DaVinciRe

DaVinciRe

5.75% Senior Notes Due March 15, 2020

5.875% Senior Notes Due February 15, 2013

5.875% Senior Notes Due February 15, 2013

5.875% Senior Notes Due February 15, 2013

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Revolving Credit Facility

Standby Letter of Credit Facility

Bilateral Facility

Bilateral Facility

Bilateral Facility

LIBOR

USD ($)

USD ($)

USD ($)

Citibank Europe PLC

Citibank Europe PLC

Citibank Europe PLC

Letter of Credit

Capital Support Agreement

USD ($)

USD ($)

RenRe North America Holdings Inc.

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Renaissance Reinsurance

USD ($)

Renaissance Reinsurance, DaVinci, RenaissanceRe Specialty Risks, ROE and RenaissanceRe Specialty U.S.

Renaissance Reinsurance, DaVinci, RenaissanceRe Specialty Risks, ROE and RenaissanceRe Specialty U.S.

RenaissanceRe Specialty Risks

DaVinciRe

Letter of Credit

Letter of Credit

Letter of Credit

USD ($)

Letter of Credit

USD ($)

USD ($)

Letter of Credit

Letter of Credit

Letter of Credit

USD ($)

GBP (£)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Debt Instrument [Line Items]

Debt Instrument, face amount

$250,000,000

$100,000,000

Senior notes interest rate

5.75%

5.88%

5.88%

Debt instrument maturity date

15-Mar-20

15-Feb-13

15-Feb-13

Net repayment of debt

0

-102,436,000

-1,937,000

0

0

100,000,000

Letter of credit aggregate commitment

250,000,000

150,000,000

Line of credit faciltiy, maximum borrowing capacity

350,000,000

300,000,000

50,000,000

Debt to capital ratio

0.4

0.35

Minimum net worth requirements

500,000,000

2,300,000,000

1,100,000,000

Letters of credit outstanding

624,900,000

83,600,000

Line of Credit Facility, Amount Outstanding

9,100,000

123,200,000

Loan agreement, remaining borrowing capacity

0

176,800,000

Margin facility amount outstanding

300,000,000

70,000,000

Collateralized letter of credit and reimbursement agreement

37,500,000

Mandatory capital contribution in the event of capital and surplus reduction below a specified level

50,000,000

Loan agreement with related party

100,000,000

200,000,000

Basis spread on variable rate

3.50%

Interest Paid

$17,200,000

$20,100,000

$23,100,000

Debt_and_Credit_Facilities_Sch

Debt and Credit Facilities (Schedule of Maturities of Long-term Debt) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Debt Disclosure [Abstract]
2015	$0
2016	0
2017	0
2018	0
2019	0
After 2019	250,000
Unamortized debt issuance expense	-478
Total	$249,522

Noncontrolling_Interests_Sched

Noncontrolling Interests (Schedule Of Redeemable Noncontrolling Interest) (Details) (USD $)	12 Months Ended			1 Months Ended			7 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 28, 2014	Jan. 31, 2014	Jan. 31, 2013	Dec. 31, 2013	Jul. 01, 2014	Jun. 30, 2014	Jan. 01, 2014	Jan. 02, 2013	Sep. 30, 2013
Activity in redeemable noncontrolling interest
Balance, Beginning	$1,099,860,000
Comprehensive income:
Net income attributable to redeemable noncontrolling interest	153,538,000	151,144,000	148,040,000
Balance, Ending	1,131,708,000	1,099,860,000					1,099,860,000
DaVinciRe
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest, ownership percentage	23.40%	27.30%	30.80%				27.30%	23.40%	26.50%	26.50%	32.90%
Redeemable Noncontrolling Interest Decrease from Redemptions or Purchase of Interests Reserve Holdback Payments				30,000,000
Activity in redeemable noncontrolling interest
Balance, Beginning	1,063,368,000	968,259,000				968,259,000
Redemption of shares from redeemable noncontrolling interests	-224,455,000	-209,356,000
Sale of shares to redeemable noncontrolling interest	48,576,000	153,884,000
Comprehensive income:
Net income attributable to redeemable noncontrolling interest	149,817,000	150,581,000	147,499,000
Balance, Ending	1,037,306,000	1,063,368,000	968,259,000				1,063,368,000
DaVinciRe | Redeemable Noncontrolling Interest
Redeemable Noncontrolling Interest [Line Items]
Redemption rights for repurchase of initial aggregate shares held, maximum	50.00%
Redeemable noncontrolling interest, net redemptions					300,000,000	150,000,000
Redeemable noncontrolling interest, Reserve holdback				60,000,000		20,500,000
Proceeds from sale of partial interest in consolidated subsidiary								38,900,000				77,400,000
DaVinciRe | Redeemable Noncontrolling Interest | Maximum
Redeemable Noncontrolling Interest [Line Items]
Share repurchase requests, limit	25.00%
Medici
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest, ownership percentage	53.20%	73.90%					73.90%
Noncontrolling interest, value subscribed	57,300,000						37,200,000
Activity in redeemable noncontrolling interest
Balance, Beginning	36,492,000	0				0
Redemption of shares from redeemable noncontrolling interests	-3,075,000	-1,325,000					-1,300,000
Sale of shares to redeemable noncontrolling interest	57,264,000	37,200,000
Comprehensive income:
Net income attributable to redeemable noncontrolling interest	3,721,000	617,000	0
Balance, Ending	94,402,000	36,492,000	0				36,492,000
Angus Fund
Activity in redeemable noncontrolling interest
Balance, Beginning	0
Comprehensive income:
Net income attributable to redeemable noncontrolling interest	0	-54,000	541,000
Balance, Ending	$0	$0					$0

Noncontrolling_Interests_Sched1

Noncontrolling Interests (Schedule Of Noncontrolling Interest) (Details) (USD $)	3 Months Ended								12 Months Ended			0 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 01, 2013
Noncontrolling Interest [Line Items]
Ownership interest with other equity investors, Amount	$0				$0				$0	$0
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Net loss attributable to noncontrolling interest	44,215,000	30,477,000	36,078,000	42,768,000	54,191,000	44,331,000	14,015,000	38,607,000	153,538,000	151,144,000	148,040,000
Angus
Noncontrolling Interest [Line Items]
Equity method investee, noncash contribution												2,300,000
Ownership %	40.40%				42.50%	38.80%			40.40%	42.50%		42.50%
Goodwill												1,700,000
Angus Fund
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance, Beginning				0				3,991,000	0	3,991,000
Adjustment in ownership interest									0	-3,709,000
Net loss attributable to noncontrolling interest									0	-54,000
Dividends on common shares									0	-228,000
Balance, Ending	0				0				0	0
Angus Fund | RRV U.S. Holdings LLC
Noncontrolling Interest [Line Items]
Ownership interest with other equity investors, Amount						55,000
Redeemable noncontrolling interest, ownership percentage						1.10%
Angus Fund | RenTech U.S. Holdings LLC
Noncontrolling Interest [Line Items]
Ownership interest with other equity investors, Amount						$2,000,000
Redeemable noncontrolling interest, ownership percentage						35.00%

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (USD $)	3 Months Ended								12 Months Ended			0 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Nov. 13, 2014	Dec. 31, 2013	Jan. 02, 2013	Jul. 02, 2013
Variable Interest Entity [Line Items]
Gross premiums written	$132,780,000	$200,992,000	$511,540,000	$705,260,000	$84,122,000	$182,649,000	$703,223,000	$635,418,000	$1,550,572,000	$1,605,412,000	$1,551,591,000
Investment in variable interest entity									0	0	0
Total assets	8,203,550,000				8,179,131,000				8,203,550,000	8,179,131,000			8,179,131,000
Total liabilities	3,206,127,000				3,174,887,000				3,206,127,000	3,174,887,000			3,174,887,000
Capital raised by third party investors	374,108,000				397,596,000				374,108,000	397,596,000			397,596,000
Ceded Premiums Earned									453,658,000	412,415,000	430,374,000
RenaissanceRe Upsilon Fund Ltd | Not Primary Beneficiary
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonredeemable Nonvoting Shares, Segregated Funds, Owned by Third Parties												100.00%
Upsilon RFO | Primary Beneficiary
Variable Interest Entity [Line Items]
Gross premiums written														53,500,000
Variable interest entity, ownership percentage			23.90%	38.90%										55.60%
Capital provided through an insurance contract			5,000,000	15,000,000										17,500,000
Risk participation percentage			15.00%	33.60%					30.50%				25.80%	42.90%
Total assets	621,300,000				474,200,000				621,300,000	474,200,000			474,200,000
Total liabilities	621,300,000				474,200,000				621,300,000	474,200,000			474,200,000
Capital raised by third party investors	135,700,000				156,300,000				135,700,000	156,300,000			156,300,000
Upsilon RFO | Primary Beneficiary | Non-voting shares
Variable Interest Entity [Line Items]
Non-voting shares issued to third parties			43,100,000	172,400,000										61,000,000
Investment in variable interest entity			13,500,000	109,700,000										76,400,000
Proceeds from sale of partial interest in consolidated subsidiary															25,000,000
Mona Lisa Re | Not Primary Beneficiary
Variable Interest Entity [Line Items]
Total assets	184,000,000				209,600,000				184,000,000	209,600,000			209,600,000
Total liabilities	184,000,000				209,600,000				184,000,000	209,600,000			209,600,000
Renaissance Reinsurance | Mona Lisa Re
Variable Interest Entity [Line Items]
Gross premiums written									7,400,000	9,200,000
Ceded Premiums Earned									8,200,000	4,800,000
DaVinciRe | Mona Lisa Re
Variable Interest Entity [Line Items]
Gross premiums written									5,100,000	6,500,000
Ceded Premiums Earned									$5,700,000	$3,500,000

Shareholders_Equity_Narrative_

Shareholders' Equity (Narrative) (Details) (USD $)	1 Months Ended	3 Months Ended								12 Months Ended			0 Months Ended					1 Months Ended	0 Months Ended	1 Months Ended
	31-May-13	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 15, 2014	Sep. 15, 2014	Jun. 13, 2014	Mar. 14, 2014	Jun. 27, 2013	Mar. 31, 2004	Dec. 27, 2012	Dec. 31, 2006	Nov. 13, 2014	Mar. 23, 2009
		director								director
		period								period
Class of Stock [Line Items]
Aggregate authorized shares		325,000,000								325,000,000
Authorized common shares		225,000,000								225,000,000
Authorized preference shares		100,000,000								100,000,000
Dividends declared, Per common share										$1.16	$1.12	$1.08
Preference Shares, Par Value (In dollars per share)		$1				$1				$1	$1
Preference shares, Issuance costs	$9,144,000
Preference shares, Shares outstanding		16,000,000				16,000,000				16,000,000	16,000,000
Preference shares, Amount of preferred dividends in arrears, equivalent number of periods, trigger		6								6
Preference shares, Preferred stock dividends in arrears, triggered shareholder election right, number of directors		2								2
Preference shares, Dividends declared and paid		5,595,000	5,595,000	5,596,000	5,595,000	5,595,000	5,595,000	7,483,000	6,275,000	22,381,000	24,948,000	34,895,000
Common stock
Class of Stock [Line Items]
Repurchase of shares										5,355,000	2,451,000	6,399,000
Common shares repurchased during period, Aggregate value										-5,355,000	-2,451,000	-6,399,000
Retained earnings
Class of Stock [Line Items]
Dividends, Common Stock										45,912,000	49,267,000	53,356,000
Common shares repurchased during period, Aggregate value										-497,175,000	-203,703,000	-460,647,000
Preference shares, Dividends declared and paid										22,381,000	24,948,000	34,895,000
Common stock
Class of Stock [Line Items]
Dividends declared, Per common share													$0.29	$0.29	$0.29	$0.29
Dividends paid, Per common share													$0.29	$0.29	$0.29	$0.29
Repurchase of shares										5,400,000
Common shares repurchased during period, Aggregate value										-514,200,000
Common shares repurchased during period, Average cost per share										$96.04
Share repurchase program, Authorized aggregate amount																					500,000,000
Remaining authorized shares per share repurchase program		500,000,000								500,000,000
Series C Preferred Stock
Class of Stock [Line Items]
Preference shares, issued																		250,000,000
Preference shares, Shares issued																		10,000,000
Preference Shares, Par Value (In dollars per share)																		$25
Preference shares, Shares redeemed	5,000,000																5,000,000
Preference shares, Redemption amount																	125,000,000
Preference shares, Shares outstanding																	5,000,000
Preference shares, Redemption price per share																						$25
Preference shares, Dividend rate										6.08%
Series D Preferred Stock
Class of Stock [Line Items]
Preference shares, issued																				300,000,000
Preference shares, Shares issued																				12,000,000
Preference Shares, Par Value (In dollars per share)																				$25
Preference shares, Shares redeemed	6,000,000																6,000,000		6,000,000
Preference shares, Redemption amount																	150,000,000		150,000,000
Preference shares, Shares outstanding																	0		6,000,000
Series E Preferred Stock
Class of Stock [Line Items]
Preference shares, issued	$275,000,000									$0	$265,856,000	$0
Preference shares, Shares issued	11,000,000
Preference Shares, Par Value (In dollars per share)	$25
Preference shares, Redemption price per share		$25								$25
Preference shares, Dividend rate										5.38%

Shareholders_Equity_Shares_Iss

Shareholders' Equity (Shares Issued and Outstanding) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued - December 31 (in shares)	38,441,972	43,646,436
Shares outstanding - December 31 (in shares)	38,441,972	43,646,436
Common stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued - January 1 (in shares)	43,646,000	45,542,000	51,543,000
Shares outstanding - January 1 (in shares)	43,646,000	45,542,000	51,543,000
Repurchase of shares	5,355,000	2,451,000	6,399,000
Exercise of options and issuance of restricted stock awards	151,000	555,000	398,000
Shares issued - December 31 (in shares)	38,442,000	43,646,000	45,542,000
Shares outstanding - December 31 (in shares)	38,442,000	43,646,000	45,542,000

Earnings_Per_Share_Computation

Earnings Per Share (Computation Of Basic And Diluted Earnings Per Common Share) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Net income available to RenaissanceRe common shareholders	$170,767	$67,815	$120,752	$151,003	$268,656	$179,740	$26,806	$190,474	$510,337	$665,676	$566,014
Amount allocated to participating common shareholders									-6,760	-9,520	-8,973
Net income allocated to RenaissanceRe common shareholders									$503,577	$656,156	$557,041
Denominator:
Denominator for basic income per RenaissanceRe common share - weighted average common shares (In shares)	37,752	38,975	39,736	41,238	43,160	43,330	43,372	43,461	39,425	43,349	48,873
Per common share equivalents of employee stock options and restricted shares (In shares)									543	779	730
Denominator for diluted income per RenaissanceRe common share - adjusted weighted average common shares and assumed conversions (In shares)	38,145	39,433	40,395	41,903	43,769	44,135	44,243	44,290	39,968	44,128	49,603
Basic income per RenaissanceRe common share (In dollars per share)	$4.46	$1.72	$3	$3.61	$6.14	$4.09	$0.61	$4.32	$12.77	$15.14	$11.40
Diluted income per RenaissanceRe common share (In dollars per share)	$4.42	$1.70	$2.95	$3.56	$6.05	$4.01	$0.60	$4.23	$12.60	$14.87	$11.23

Related_Party_Transactions_and1

Related Party Transactions and Major Customers (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Related Party Transaction [Line Items]
Gross premiums written	$132,780,000	$200,992,000	$511,540,000	$705,260,000	$84,122,000	$182,649,000	$703,223,000	$635,418,000	$1,550,572,000	$1,605,412,000	$1,551,591,000
Gross premiums earned									1,450,047,000	1,482,511,000	1,465,701,000
Acquisition expenses	39,749,000	37,550,000	33,477,000	33,700,000	31,026,000	37,699,000	31,767,000	25,009,000	144,476,000	125,501,000	113,542,000
Net reinsurance costs and recoveries									-30,634,000	-13,852,000	-78,280,000
Reserve for claims and claim expenses	1,412,510,000				1,563,730,000				1,412,510,000	1,563,730,000	1,879,377,000
Distributions received									10,300,000	9,900,000	9,900,000
Equity interest investment in related party	143,632,000				139,382,000				143,632,000	139,382,000
Catastrophe Reinsurance and Specialty Reinsurance | Gross Premiums Written
Related Party Transaction [Line Items]
Percent of gross premiums received									89.20%	88.20%	84.60%
Number of significant customers									3
Catastrophe Reinsurance and Specialty Reinsurance | Gross Premiums Written | AON Benfield
Related Party Transaction [Line Items]
Percent of gross premiums received									56.10%	48.60%	51.50%
Catastrophe Reinsurance and Specialty Reinsurance | Gross Premiums Written | Marsh Inc.
Related Party Transaction [Line Items]
Percent of gross premiums received									21.20%	22.70%	21.40%
Catastrophe Reinsurance and Specialty Reinsurance | Gross Premiums Written | Willis Group
Related Party Transaction [Line Items]
Percent of gross premiums received									11.90%	16.90%	11.70%
Tower Hill
Related Party Transaction [Line Items]
Gross premiums written									40,000,000	46,700,000	41,100,000
Gross premiums earned									41,900,000	44,900,000	36,100,000
Acquisition expenses									4,700,000	5,300,000	3,900,000
Related party receivables	18,300,000				20,200,000				18,300,000	20,200,000
Net reinsurance costs and recoveries									3,600,000	4,100,000	4,000,000
Reserve for claims and claim expenses	40,300,000				37,100,000				40,300,000	37,100,000
Distributions received									10,000,000	9,800,000
Angus
Related Party Transaction [Line Items]
Equity interest investment in related party	10,500,000								10,500,000
Ownership %	40.40%								40.40%
Related party income									0	5,000,000	7,900,000
Top Layer Re
Related Party Transaction [Line Items]
Distributions received									0	0	0
Management fees revenue									$2,800,000	$3,800,000	$4,100,000

Taxation_Income_Before_Income_

Taxation (Income Before Income Taxes, Foreign and Domestic) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Expense (Benefit)
Income from continuing operations before taxes	$220,978	$104,132	$162,222	$199,532	$329,778	$239,668	$45,888	$225,704	$686,864	$841,038	$766,838
Bermuda | Domestic Country
Income Tax Expense (Benefit)
Domestic									701,476	873,103	795,378
United Kingdom | Foreign
Income Tax Expense (Benefit)
Foreign									-3,166	-12,678	-15,404
U.S. | Internal Revenue Service (IRS)
Income Tax Expense (Benefit)
Foreign									-10,977	-20,019	-16,467
Ireland | Foreign
Income Tax Expense (Benefit)
Foreign									1,549	1,855	3,318
Singapore | Foreign
Income Tax Expense (Benefit)
Foreign									($2,018)	($1,223)	$13

Taxation_Components_of_Income_

Taxation (Components of Income Tax Benefit (Expense)) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Expense (Benefit)
Current									($699)	($2,005)	($1,667)
Deferred									91	313	254
Income tax (expense) benefit	($401)	($245)	$204	($166)	($1,336)	($223)	($11)	($122)	($608)	($1,692)	($1,413)

Taxation_Income_Tax_Reconcilia

Taxation (Income Tax Reconciliation) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax [Line Items]
Expected income tax benefit									$4,725	$9,930	$8,889
Change in valuation allowance									-5,554	-8,574	-6,212
Other									221	-3,048	-4,090
Income tax (expense) benefit	($401)	($245)	$204	($166)	($1,336)	($223)	($11)	($122)	($608)	($1,692)	($1,413)
Bermuda | Domestic Country
Income Tax [Line Items]
Statutory income tax rate									0.00%
U.S. | Internal Revenue Service (IRS)
Income Tax [Line Items]
Foreign statutory income tax rate									35.00%
Ireland | Foreign
Income Tax [Line Items]
Foreign statutory income tax rate									12.50%
United Kingdom | Foreign
Income Tax [Line Items]
Foreign statutory income tax rate									21.50%
Singapore | Foreign
Income Tax [Line Items]
Foreign statutory income tax rate									17.00%

Taxation_Deferred_Tax_Assets_a

Taxation (Deferred Tax Assets and Liabilities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Tax Assets
Tax loss and credit carryforwards	$37,933	$34,429
Deferred interest expense	17,066	12,608
Accrued expenses	3,413	1,096
Amortization and depreciation	1,686	1,730
Deferred underwriting results	1,586	1,873
Investments	290	4,694
Deferred Tax Assets, Gross	61,974	56,430
Deferred Tax Liabilities
Amortization and depreciation	-54	-155
Deferred Tax Liabilities	-54	-155
Net deferred tax asset before valuation and allowance	61,920	56,275
Valuation allowance	-61,660	-56,106
Net deferred tax asset (liability)	$260	$169

Taxation_Narrative_Details

Taxation (Narrative) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	$5.60	$21	$6.20
Income taxes paid	1.1	1.2
Income tax refund			-13.2
Unrecognized tax benefits	0	0
Interest and penalties accrued on unrecognized tax benefits	0
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	65
Ireland
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	10.8
United Kingdom
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	45.5
Singapore
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$3.90

Segment_Reporting_Schedule_Of_

Segment Reporting (Schedule Of Significant Components Of The Company's Revenues And Expenses) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Gross premiums written	$132,780	$200,992	$511,540	$705,260	$84,122	$182,649	$703,223	$635,418	$1,550,572	$1,605,412	$1,551,591
Net premiums written	111,769	159,713	346,407	450,347	80,784	127,241	559,109	436,813	1,068,236	1,203,947	1,102,657
Net premiums earned	256,487	258,979	260,416	286,534	256,765	294,717	291,889	271,255	1,062,416	1,114,626	1,069,355
Net claims and claim expenses incurred	-12,003	69,647	81,388	58,915	-20,854	60,928	103,962	27,251	197,947	171,287	325,211
Acquisition expenses	39,749	37,550	33,477	33,700	31,026	37,699	31,767	25,009	144,476	125,501	113,542
Operational expenses	55,202	46,972	45,841	42,624	57,658	44,672	42,789	45,986	190,639	191,105	179,151
Underwriting income (loss)									529,354	626,733	451,451
Net investment income	25,886	24,941	34,541	38,948	78,732	59,931	26,163	43,202	124,316	208,028	165,725
Net foreign exchange gains	-107	5,036	2,392	-1,061	1,747	488	-932	614	6,260	1,917	5,319
Equity in earnings of other ventures	4,838	9,806	7,232	4,199	6,274	7,313	3,772	5,835	26,075	23,194	23,238
Other loss	1,219	-1,169	-535	62	-173	651	-1,128	-1,709	-423	-2,359	-2,120
Net realized and unrealized gains on investments	30,475	-31,097	27,128	14,927	61,864	28,472	-69,529	14,269	41,433	35,076	163,121
Net other-than-temporary impairments recognized in earnings									0	0	-343
Corporate expenses	-10,583	-3,905	-3,954	-4,545	-3,304	-4,307	-21,529	-4,482	-22,987	-33,622	-16,456
Interest expense	-4,289	-4,290	-4,292	-4,293	-4,297	-4,298	-4,300	-5,034	-17,164	-17,929	-23,097
Income from continuing operations before taxes	220,978	104,132	162,222	199,532	329,778	239,668	45,888	225,704	686,864	841,038	766,838
Income tax (expense) benefit	-401	-245	204	-166	-1,336	-223	-11	-122	-608	-1,692	-1,413
Income (loss) from discontinued operations	0	0	0	0	0	-9,779	2,427	9,774	0	2,422	-16,476
Net income attributable to noncontrolling interests	-44,215	-30,477	-36,078	-42,768	-54,191	-44,331	-14,015	-38,607	-153,538	-151,144	-148,040
Dividends on preference shares	-5,595	-5,595	-5,596	-5,595	-5,595	-5,595	-7,483	-6,275	-22,381	-24,948	-34,895
Net income available to RenaissanceRe common shareholders	170,767	67,815	120,752	151,003	268,656	179,740	26,806	190,474	510,337	665,676	566,014
Net claims and claim expenses incurred - current accident year									341,745	315,241	483,180
Net claims and claim expenses incurred – prior accident years									-143,798	-143,954	-157,969
Total net incurred									197,947	171,287	325,211
Net claims and claim expense ratio - current accident year									32.20%	28.30%	45.20%
Net claims and claim expense ratio - prior accident years									-13.60%	-12.90%	-14.80%
Net claims and claim expense ratio - calendar year									18.60%	15.40%	30.40%
Underwriting expense ratio									31.60%	28.40%	27.40%
Combined ratio									50.20%	43.80%	57.80%
Catastrophe Reinsurance
Segment Reporting Information [Line Items]
Gross premiums written									933,969	1,120,379	1,182,207
Net premiums written									541,608	753,078	766,035
Net premiums earned									590,845	723,705	781,738
Net claims and claim expenses incurred									1,757	7,908	165,209
Acquisition expenses									43,161	49,161	66,665
Operational expenses									95,851	108,130	103,811
Underwriting income (loss)									450,076	558,506	446,053
Net claims and claim expenses incurred - current accident year									67,268	109,945	275,777
Net claims and claim expenses incurred – prior accident years									-65,511	-102,037	-110,568
Total net incurred									1,757	7,908	165,209
Net claims and claim expense ratio - current accident year									11.40%	15.20%	35.30%
Net claims and claim expense ratio - prior accident years									-11.10%	-14.10%	-14.20%
Net claims and claim expense ratio - calendar year									0.30%	1.10%	21.10%
Underwriting expense ratio									23.50%	21.70%	21.80%
Combined ratio									23.80%	22.80%	42.90%
Specialty Reinsurance
Segment Reporting Information [Line Items]
Gross premiums written									346,638	259,489	209,887
Net premiums written									295,855	248,562	201,552
Net premiums earned									253,537	214,306	164,685
Net claims and claim expenses incurred									88,502	67,236	76,813
Acquisition expenses									60,936	41,538	23,826
Operational expenses									43,370	31,780	29,124
Underwriting income (loss)									60,729	73,752	34,922
Net claims and claim expenses incurred - current accident year									144,411	101,347	110,959
Net claims and claim expenses incurred – prior accident years									-55,909	-34,111	-34,146
Total net incurred									88,502	67,236	76,813
Net claims and claim expense ratio - current accident year									57.00%	47.30%	67.40%
Net claims and claim expense ratio - prior accident years									-22.10%	-15.90%	-20.80%
Net claims and claim expense ratio - calendar year									34.90%	31.40%	46.60%
Underwriting expense ratio									41.10%	34.20%	32.20%
Combined ratio									76.00%	65.60%	78.80%
Lloyd's
Segment Reporting Information [Line Items]
Gross premiums written									269,656	226,532	159,987
Net premiums written									230,429	201,697	135,131
Net premiums earned									217,666	176,029	122,968
Net claims and claim expenses incurred									113,825	95,693	80,242
Acquisition expenses									46,927	34,823	22,864
Operational expenses									51,115	50,540	45,680
Underwriting income (loss)									5,799	-5,027	-25,818
Net claims and claim expenses incurred - current accident year									130,066	103,949	96,444
Net claims and claim expenses incurred – prior accident years									-16,241	-8,256	-16,202
Total net incurred									113,825	95,693	80,242
Net claims and claim expense ratio - current accident year									59.80%	59.10%	78.40%
Net claims and claim expense ratio - prior accident years									-7.50%	-4.70%	-13.10%
Net claims and claim expense ratio - calendar year									52.30%	54.40%	65.30%
Underwriting expense ratio									45.00%	48.50%	55.70%
Combined ratio									97.30%	102.90%	121.00%
Other
Segment Reporting Information [Line Items]
Gross premiums written									309	-988	-490
Net premiums written									344	610	-61
Net premiums earned									368	586	-36
Net claims and claim expenses incurred									-6,137	450	2,947
Acquisition expenses									-6,548	-21	187
Operational expenses									303	655	536
Underwriting income (loss)									12,750	-498	-3,706
Net investment income									124,316	208,028	165,725
Net foreign exchange gains									6,260	1,917	5,319
Equity in earnings of other ventures									26,075	23,194	23,238
Other loss									-423	-2,359	-2,120
Net realized and unrealized gains on investments									41,433	35,076	163,121
Net other-than-temporary impairments recognized in earnings											-343
Corporate expenses									-22,987	-33,622	-16,456
Interest expense									-17,164	-17,929	-23,097
Income tax (expense) benefit									-608	-1,692	-1,413
Income (loss) from discontinued operations										2,422	-16,476
Net income attributable to noncontrolling interests									-153,538	-151,144	-148,040
Dividends on preference shares									-22,381	-24,948	-34,895
Net claims and claim expenses incurred - current accident year									0	0	0
Net claims and claim expenses incurred – prior accident years									-6,137	450	2,947
Total net incurred									-6,137	450	2,947
Net claims and claim expense ratio - current accident year									0.00%	0.00%	0.00%
Net claims and claim expense ratio - prior accident years									-1667.70%	76.80%	-8186.10%
Net claims and claim expense ratio - calendar year									-1667.70%	76.80%	-8186.10%
Underwriting expense ratio									-1697.00%	108.20%	-2008.30%
Combined ratio									-3364.70%	185.00%	-10194.40%
Intersegment Eliminations
Segment Reporting Information [Line Items]
Gross premiums written									$300	($1,000)	($500)

Segment_Reporting_Schedule_Of_1

Segment Reporting (Schedule Of Gross Premiums Written Allocated To the Territory Of Coverage Exposure) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written	$132,780	$200,992	$511,540	$705,260	$84,122	$182,649	$703,223	$635,418	$1,550,572	$1,605,412	$1,551,591
Catastrophe Reinsurance
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									933,969	1,120,379	1,182,207
Catastrophe Reinsurance | U.S. and Caribbean
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									573,696	782,211	857,740
Catastrophe Reinsurance | Worldwide
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									157,674	99,179	81,595
Catastrophe Reinsurance | Worldwide (excluding U.S.)
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									123,476	146,048	139,265
Catastrophe Reinsurance | Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									31,484	39,060	43,238
Catastrophe Reinsurance | Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									25,353	25,659	37,113
Catastrophe Reinsurance | Australia and New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									20,807	22,460	18,578
Catastrophe Reinsurance | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									1,479	5,762	4,678
Specialty Reinsurance
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									346,638	259,489	209,887
Specialty Reinsurance | U.S. and Caribbean
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									169,045	91,203	69,070
Specialty Reinsurance | Worldwide
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									161,329	151,879	96,081
Specialty Reinsurance | Worldwide (excluding U.S.)
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									7,506	1,661	0
Specialty Reinsurance | Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									460	2,612	16,429
Specialty Reinsurance | Australia and New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									6,898	12,068	28,307
Specialty Reinsurance | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									1,400	66	0
Lloyd's
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									269,656	226,532	159,987
Lloyd's | U.S. and Caribbean
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									120,066	88,535	57,332
Lloyd's | Worldwide
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									118,190	104,249	75,132
Lloyd's | Worldwide (excluding U.S.)
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									13,655	8,071	6,064
Lloyd's | Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									7,609	14,763	14,456
Lloyd's | Australia and New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									2,907	2,948	2,152
Lloyd's | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									7,229	7,966	4,851
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									309	-988	-490
Intersegment Eliminations
Revenues from External Customers and Long-Lived Assets [Line Items]
Gross premiums written									$300	($1,000)	($500)

Stock_Incentive_Compensation_a2

Stock Incentive Compensation and Employee Benefit Plans (Narrative) (Details) (USD $)	12 Months Ended			81 Months Ended	0 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	20-May-14	Jul. 01, 2013	31-May-10	Dec. 31, 2010	Aug. 31, 2004
						D
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant	3,000,000
Total fair value of shares and share units vested	$48,700,000	$47,000,000	$43,300,000
Cash received from exercises of stock options during the period	500,000	1,600,000	900,000
Excess windfall tax benefit realized by the Company due to its net operating loss position in the taxable jurisdictions in which it operates	0
Total stock compensation expense recognized	37,600,000	43,400,000	38,400,000
Contributions to defined contribution pension plans	3,600,000	3,500,000	3,400,000
Premium Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive compensation, vesting period				5 years
Shares reserved for issuance under Premium Option Plan								6,000,000
Minimum strike price as a percentage of market value on grant date				150.00%
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive compensation, vesting period					4 years	3 years
Number of shares available for grant						750,000
Percentage of annual equity incentive award grants, subject to vesting conditions						25.00%
Vesting maximum as a percentage of target if performance goal are achieved					250.00%	250.00%
Period for average closing share price to determine total shareholder return						20
Employee Stock Option | 2001 Stock Incentive Plans and Nonemployee Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive compensation, vesting period	4 years
Share-based payment award, Expiration period	10 years
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to restricted stock awards	21,600,000
Periods for recognition of compensation costs not yet recognized	1 year 7 months 6 days
Cash Settled Restricted Stock Unit (CSRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive compensation, vesting period							4 years
Number of shares available for grant							900,000
Expected forfeiture rate	11.00%	13.00%
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected forfeiture rate	0.00%	0.00%
Unrecognized compensation costs related to restricted stock awards	4,300,000
Periods for recognition of compensation costs not yet recognized	1 year 10 months 24 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected forfeiture rate	2.00%	2.00%
Unrecognized compensation costs related to restricted stock awards	$30,700,000
Periods for recognition of compensation costs not yet recognized	1 year 9 months 18 days
Restricted Stock | 2001 Stock Incentive Plans and Nonemployee Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive compensation, vesting period	4 years

Stock_Incentive_Compensation_a3

Stock Incentive Compensation and Employee Benefit Plans (Schedule of Valuation Assumptions) (Details) (Performance Shares)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility rate, minimum	14.50%	19.00%
Expected volatility rate, maximum	18.60%	19.60%
Risk free interest rate, minimum	0.08%	0.09%
Risk free interest rate, maximum	1.65%	1.39%
Expected term	1 year
Expected forfeiture rate	0.00%	0.00%

Stock_Incentive_Compensation_a4

Stock Incentive Compensation and Employee Benefit Plans (Schedule of Option Activity) (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
2001 Stock Incentive Plans and Nonemployee Directors
Weighted options outstanding:
Balance, Beginning of Period (shares)	828,092	1,732,639	1,973,307
Options granted (in shares)	0	0	0
Options forfeited (in shares)	0	0	0
Options expired (in shares)	0	0	0
Options exercised (in shares)	-60,262	-904,547	-240,668
Balance, End of Period (shares)	767,830	828,092	1,732,639	1,973,307
Weighted average exercise price:
Weighted average exercise price, Beginning of Period (In dollars per share)	$48.77	$47.61	$47.33
Options granted, Weighted average exercise price (In dollars per share)	$0	$0	$0
Options forfeited, Weighted average exercise price (In dollars per share)	$0	$0	$0
Options expired, Weighted average exercise price (In dollars per share)	$0	$0	$0
Options exercised, Weighted average exercise price (In dollars per share)	$49.52	$46.55	$45.30
Weighted average exercise price, End of Period (In dollars per share)	$48.71	$48.77	$47.61	$47.33
Weighted average remaining contractual life	2 years	2 years 10 months 24 days	3 years 8 months	4 years 7 months
Aggregate Intrinsic Value [Abstract]
Aggregate intrinsic value	$37,246	$40,221	$58,305	$53,363
Options exercised, Aggregate intrinsic value	2,900	36,800	7,910
Range of Exercise Prices [Abstract]
Exercise price range, lower range limit (In dollars per share)	$37.51	$37.51	$37.51	$37.51
Exercise price range, upper range limit (In dollars per share)	$59.66	$59.66	$59.66	$59.66
Total options exercisable, minimum (In dollars per share)	$37.51
Total options exercisable, maximum (In dollars per share)	$59.66
Total options exercisable (in shares)	767,830
Total options exercisable, Weighted average exercise price (In dollars per share)	$48.71
Total options exercisable, Weighted average remaining contractual life	2 years
Total options exercisable, Aggregate intrinsic value	37,246
Premium Option Plan
Weighted options outstanding:
Balance, Beginning of Period (shares)	572,000	842,000	1,192,000
Options granted (in shares)	0	0	0
Options forfeited (in shares)	0	0	0
Options expired (in shares)	0	0	0
Options exercised (in shares)	-572,000	-270,000	-350,000
Balance, End of Period (shares)	0	572,000	842,000	1,192,000
Weighted average exercise price:
Weighted average exercise price, Beginning of Period (In dollars per share)	$73.62	$73.82	$73.94
Options granted, Weighted average exercise price (In dollars per share)	$0	$0	$0
Options forfeited, Weighted average exercise price (In dollars per share)	$0	$0	$0
Options expired, Weighted average exercise price (In dollars per share)	$0	$0	$0
Options exercised, Weighted average exercise price (In dollars per share)	$73.62	$74.24	$74.24
Weighted average exercise price, End of Period (In dollars per share)	$0	$73.62	$73.82	$73.94
Weighted average remaining contractual life	0 years
Aggregate Intrinsic Value [Abstract]
Aggregate intrinsic value	0	13,567	6,265	0
Options exercised, Aggregate intrinsic value	13,414	4,921	1,250
Range of Exercise Prices [Abstract]
Exercise price range, lower range limit (In dollars per share)	$0	$73.06	$73.06	$73.06
Exercise price range, upper range limit (In dollars per share)	$0	$74.24	$74.24	$74.24
Total options exercisable, minimum (In dollars per share)	$0
Total options exercisable, maximum (In dollars per share)	$0
Total options exercisable (in shares)	0
Total options exercisable, Weighted average exercise price (In dollars per share)	$0
Total options exercisable, Weighted average remaining contractual life	0 years
Total options exercisable, Aggregate intrinsic value	$0

Stock_Incentive_Compensation_a5

Stock Incentive Compensation and Employee Benefit Plans (Equity Compensation Other than Options) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of shares:
Nonvested at Beginning of Period (in shares)	600,978	682,671	804,346
Awards granted (in shares)	229,509	258,233	243,701
Awards vested (in shares)	-348,611	-332,933	-358,219
Awards forfeited (in shares)	-99	-6,993	-7,157
Nonvested at End of Period (in shares)	481,777	600,978	682,671
Weighted average grant-dated fair value:
Nonvested, Weighted average grant-dated fair value, at Beginning of Period (In dollars per share)	$76.24	$61.90	$53.91
Awards granted, Weighted average grant-dated fair value (In dollars per share)	$95.74	$87.82	$72.40
Awards vested, Weighted average grant-dated fair value (In dollars per share)	$73.79	$56.31	$51.26
Awards forfeited, Weighted average grant-dated fair value (In dollars per share)	$55.80	$58.14	$53.90
Nonvested, Weighted average grant-dated fair value, at End of Period (In dollars per share)	$87.36	$76.24	$61.90
Cash Settled Restricted Stock Unit (CSRSUs)
Number of shares:
Nonvested at Beginning of Period (in shares)	394,145	493,556	422,973
Awards granted (in shares)	119,382	149,760	225,105
Awards vested (in shares)	-159,094	-176,265	-128,401
Awards forfeited (in shares)	-16,110	-72,906	-26,121
Nonvested at End of Period (in shares)	338,323	394,145	493,556
Employee restricted stock
Number of shares:
Nonvested at Beginning of Period (in shares)	569,492	646,748	764,761
Awards granted (in shares)	215,054	241,071	226,827
Awards vested (in shares)	-332,725	-311,334	-337,683
Awards forfeited (in shares)	-99	-6,993	-7,157
Nonvested at End of Period (in shares)	451,722	569,492	646,748
Weighted average grant-dated fair value:
Nonvested, Weighted average grant-dated fair value, at Beginning of Period (In dollars per share)	$76.11	$61.63	$53.68
Awards granted, Weighted average grant-dated fair value (In dollars per share)	$95.79	$87.85	$72.46
Awards vested, Weighted average grant-dated fair value (In dollars per share)	$73.74	$55.63	$51.06
Awards forfeited, Weighted average grant-dated fair value (In dollars per share)	$55.80	$58.14	$53.90
Nonvested, Weighted average grant-dated fair value, at End of Period (In dollars per share)	$87.29	$76.11	$61.63
Non-employee director restricted stock
Number of shares:
Nonvested at Beginning of Period (in shares)	31,486	35,923	39,585
Awards granted (in shares)	14,455	17,162	16,874
Awards vested (in shares)	-15,886	-21,599	-20,536
Awards forfeited (in shares)	0	0	0
Nonvested at End of Period (in shares)	30,055	31,486	35,923
Weighted average grant-dated fair value:
Nonvested, Weighted average grant-dated fair value, at Beginning of Period (In dollars per share)	$78.57	$66.83	$58.43
Awards granted, Weighted average grant-dated fair value (In dollars per share)	$95.06	$87.40	$71.69
Awards vested, Weighted average grant-dated fair value (In dollars per share)	$74.96	$66.06	$54.62
Awards forfeited, Weighted average grant-dated fair value (In dollars per share)	$0	$0	$0
Nonvested, Weighted average grant-dated fair value, at End of Period (In dollars per share)	$88.41	$78.57	$66.83
Performance Shares
Number of shares:
Nonvested at Beginning of Period (in shares)	359,543	359,520	289,867
Awards granted (in shares)	102,668	134,358	144,635
Awards vested (in shares)	0	-24,606	-70,843
Awards forfeited (in shares)	-213,639	-109,729	-4,139
Nonvested at End of Period (in shares)	248,572	359,543	359,520
Weighted average grant-dated fair value:
Nonvested, Weighted average grant-dated fair value, at Beginning of Period (In dollars per share)	$30.55	$29.46	$30.06
Awards granted, Weighted average grant-dated fair value (In dollars per share)	$46.45	$33.46	$28.17
Nonvested, Weighted average grant-dated fair value, at End of Period (In dollars per share)	$39.62	$30.55	$29.46

Statutory_Requirements_Statuto

Statutory Requirements (Statutory Capital and Surplus) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Bermuda
Statutory Accounting Practices [Line Items]
Actual statutory capital and surplus	$3,375,317	$3,194,446
Required statutory capital and surplus	479,346	562,126
Restricted net assets	1,018,878	887,083
United Kingdom
Statutory Accounting Practices [Line Items]
Actual statutory capital and surplus	409,046	380,336
Required statutory capital and surplus	409,046	380,336
Restricted net assets	$0	$0

Statutory_Requirements_Statuto1

Statutory Requirements (Statutory Net Income (Loss)) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Bermuda
Statutory Accounting Practices [Line Items]
Statutory net income (loss) of regulated operations	$623,931	$712,820	$693,887
United Kingdom
Statutory Accounting Practices [Line Items]
Statutory net income (loss) of regulated operations	$24,433	$7,745	($10,967)

Statutory_Requirements_Narrati

Statutory Requirements (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Statutory Accounting Practices [Line Items]
Retained earnings available for payment of dividends or distribution to shareholders	2,400,000,000	$2,600,000,000
Assets held in trust	2,379,400,000	2,081,100,000
Renaissance Reinsurance | Bermuda
Statutory Accounting Practices [Line Items]
Unrecorded liabilities, exempt by regulatory authority	468,600,000	168,000,000
Multi-Beneficiary Reinsurance Trust | Renaissance Reinsurance | New York
Statutory Accounting Practices [Line Items]
Assets held in trust	508,600,000	505,100,000
Multi-Beneficiary Reinsurance Trust | DaVinciRe | New York
Statutory Accounting Practices [Line Items]
Assets held in trust	173,700,000	173,900,000
Multi-Beneficiary Reduced Collateral Reinsurance Trust | New York
Statutory Accounting Practices [Line Items]
Multi-beneficiary reduced collateral reinsurance trust collateral reduction	20.00%
Multi-Beneficiary Reduced Collateral Reinsurance Trust | Renaissance Reinsurance | New York
Statutory Accounting Practices [Line Items]
Assets held in trust	43,200,000	21,100,000
Multi-Beneficiary Reduced Collateral Reinsurance Trust | DaVinciRe | New York
Statutory Accounting Practices [Line Items]
Assets held in trust	18,800,000	18,600,000
Minimum | Multi-Beneficiary Reinsurance Trust | Renaissance Reinsurance | New York
Statutory Accounting Practices [Line Items]
Assets held in trust	409,900,000	441,700,000
Minimum | Multi-Beneficiary Reinsurance Trust | DaVinciRe | New York
Statutory Accounting Practices [Line Items]
Assets held in trust	105,700,000	135,200,000
Minimum | Multi-Beneficiary Reduced Collateral Reinsurance Trust | Renaissance Reinsurance | New York
Statutory Accounting Practices [Line Items]
Assets held in trust	17,500,000	16,300,000
Minimum | Multi-Beneficiary Reduced Collateral Reinsurance Trust | DaVinciRe | New York
Statutory Accounting Practices [Line Items]
Assets held in trust	10,300,000	$10,200,000

Derivative_Instruments_Consoli

Derivative Instruments (Consolidated Balance Sheets And Fair Value Of The Principal Derivative Instruments) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Other Assets
Derivative Assets [Abstract]
Gross Amounts of Recognized Assets	$10,635	$12,328
Gross Amounts Offset in the Balance Sheet	2,941	1,661
Net Amounts of Assets Presented in the Balance Sheet	7,694	10,667
Collateral	310	310
Net Amount	7,384	10,357
Other Assets | Interest Rate Futures
Derivative Assets [Abstract]
Gross Amounts of Recognized Assets	468	897
Gross Amounts Offset in the Balance Sheet	468	62
Net Amounts of Assets Presented in the Balance Sheet	0	835
Collateral	0	0
Net Amount	0	835
Other Assets | Foreign Currency Forward Contracts, Underwriting and Non-investment Operations
Derivative Assets [Abstract]
Gross Amounts of Recognized Assets	5,740	9,612
Gross Amounts Offset in the Balance Sheet	1,737	1,179
Net Amounts of Assets Presented in the Balance Sheet	4,003	8,433
Collateral	0	0
Net Amount	4,003	8,433
Other Assets | Foreign Currency Forward Contracts, Investment Operations
Derivative Assets [Abstract]
Gross Amounts of Recognized Assets	3,959	1,013
Gross Amounts Offset in the Balance Sheet	648	338
Net Amounts of Assets Presented in the Balance Sheet	3,311	675
Collateral	0	0
Net Amount	3,311	675
Other Assets | Credit Default Swaps
Derivative Assets [Abstract]
Gross Amounts of Recognized Assets	468	806
Gross Amounts Offset in the Balance Sheet	88	82
Net Amounts of Assets Presented in the Balance Sheet	380	724
Collateral	310	310
Net Amount	70	414
Other Liabilities
Derivative Liabilities [Abstract]
Gross Amounts of Recognized Liabilities	3,521	6,419
Gross Amounts Offset in the Balance Sheet	2,172	510
Net Amounts of Liabilities Presented in the Balance Sheet	1,349	5,909
Collateral	759	2,502
Net Amount	590	3,407
Other Liabilities | Interest Rate Futures
Derivative Liabilities [Abstract]
Gross Amounts of Recognized Liabilities	1,037	74
Gross Amounts Offset in the Balance Sheet	468	62
Net Amounts of Liabilities Presented in the Balance Sheet	569	12
Collateral	569	12
Net Amount	0	0
Other Liabilities | Foreign Currency Forward Contracts, Underwriting and Non-investment Operations
Derivative Liabilities [Abstract]
Gross Amounts of Recognized Liabilities	1,319	2,204
Gross Amounts Offset in the Balance Sheet	967	28
Net Amounts of Liabilities Presented in the Balance Sheet	352	2,176
Collateral	0	0
Net Amount	352	2,176
Other Liabilities | Foreign Currency Forward Contracts, Investment Operations
Derivative Liabilities [Abstract]
Gross Amounts of Recognized Liabilities	724	1,557
Gross Amounts Offset in the Balance Sheet	649	338
Net Amounts of Liabilities Presented in the Balance Sheet	75	1,219
Collateral	0	0
Net Amount	75	1,219
Other Liabilities | Credit Default Swaps
Derivative Liabilities [Abstract]
Gross Amounts of Recognized Liabilities	251	94
Gross Amounts Offset in the Balance Sheet	88	82
Net Amounts of Liabilities Presented in the Balance Sheet	163	12
Collateral	0	0
Net Amount	163	12
Other Liabilities | Weather Contract
Derivative Liabilities [Abstract]
Gross Amounts of Recognized Liabilities	190	2,490
Gross Amounts Offset in the Balance Sheet	0	0
Net Amounts of Liabilities Presented in the Balance Sheet	190	2,490
Collateral	190	2,490
Net Amount	$0	$0

Derivative_Instruments_Gain_Lo

Derivative Instruments (Gain (Loss) Recognized In The Consolidated Statements Of Operations Related To Its Derivative Instruments) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized on derivatives	($13,851)	$27,601	$9,687
Net realized and unrealized gains on investments | Interest Rate Futures
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized on derivatives	-32,713	29,695	-1,746
Net realized and unrealized gains on investments | Credit Default Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized on derivatives	328	1,363	1,074
Net realized and unrealized gains on investments | Weather Contract
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized on derivatives	1,454	-1,331	0
Net foreign exchange gains | Foreign Currency Forward Contracts, Underwriting and Non-investment Operations
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized on derivatives	4,457	889	13,804
Net foreign exchange gains | Foreign Currency Forward Contracts, Investment Operations
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized on derivatives	$12,623	($3,015)	($3,445)

Derivative_Instruments_Narrati

Derivative Instruments (Narrative) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Long | Interest Rate Futures
Derivative [Line Items]
Derivative, Notional Amount	$587	$1,169.30
Long | Foreign Currency Forward Contracts, Underwriting and Non-investment Operations
Derivative [Line Items]
Derivative, Notional Amount	144.8	263.6
Long | Foreign Currency Forward Contracts, Investment Operations
Derivative [Line Items]
Derivative, Notional Amount	35.8	39.6
Long | Credit Default Swaps
Derivative [Line Items]
Derivative, Notional Amount	4.6	7.1
Short | Interest Rate Futures
Derivative [Line Items]
Derivative, Notional Amount	617.4	356.6
Short | Foreign Currency Forward Contracts, Underwriting and Non-investment Operations
Derivative [Line Items]
Derivative, Notional Amount	121.6	139.8
Short | Foreign Currency Forward Contracts, Investment Operations
Derivative [Line Items]
Derivative, Notional Amount	150.1	159.1
Short | Credit Default Swaps
Derivative [Line Items]
Derivative, Notional Amount	19.4	18.4
Short | Weather Contract
Derivative [Line Items]
Derivative, Notional Amount	$2.20	$6.40

Commitments_Contingencies_and_2

Commitments, Contingencies and Other Items (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies [Line Items]
Percentage of aggregate outstanding letters of credit secured	75.00%
Percentage of aggregate outstanding letters of credit subject to certain financial covenants	25.00%
Initial commitments	$623,800,000
Fulfilled commitments	544,100,000
Unfunded commitments	84,000,000
Maximum | Investments as a Percentage of Shareholders' Equity
Commitments and Contingencies [Line Items]
Concentration risk percentage	10.00%
Letter of Credit
Commitments and Contingencies [Line Items]
Letters of credit outstanding	624,900,000
Top Layer Re | Letter of Credit
Commitments and Contingencies [Line Items]
Collateral pledged to support letter of credit	37,500,000
Capital Support Agreement | Top Layer Re | Letter of Credit
Commitments and Contingencies [Line Items]
Maximum mandatory capital contribution in the event of loss that reduced capital and surplus below specified level	$50,000,000

Commitments_Contingencies_and_3

Commitments, Contingencies and Other Items (Future Minimum Payments, Operating Leases) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
2015	$6,184
2016	5,234
2017	2,321
2018	2,035
2019	1,455
After 2019	142
Future minimum lease payments under existing operating leases	$17,371

Commitments_Contingencies_and_4

Commitments, Contingencies and Other Items (Capital Leases) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Initial capital lease term	20 years
Bargain renewal option term	30 years
2015	$3,017
2016	3,017
2017	2,417
2018	2,501
2019	2,661
After 2019	23,433
Future minimum lease payments under existing capital leases	$37,046

Commitments_Contingencies_and_5

Commitments, Contingencies and Other Items (Merger Agreement) (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 15, 2014	Sep. 15, 2014	Jun. 13, 2014	Mar. 14, 2014	Dec. 31, 2014	Mar. 02, 2015	Feb. 10, 2015
Business Acquisition [Line Items]
Common Stock, Par or Stated Value Per Share	$1	$1						1
Dividends declared, Per common share	$1.16	$1.12	$1.08
Common stock
Business Acquisition [Line Items]
Dividends declared, Per common share				$0.29	$0.29	$0.29	$0.29
Platinum
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs	$6,700,000							6,700,000
Platinum | Common stock
Business Acquisition [Line Items]
Number of shares to be issued for acquisition								7,500,000
Cash Election | Platinum
Business Acquisition [Line Items]
Cash per share	$66							66
Share Election | Platinum
Business Acquisition [Line Items]
Common share per share	0.6504							0.6504
Standard Election | Platinum
Business Acquisition [Line Items]
Cash per share	$35.96							35.96
Common share per share	0.296							0.296
Scenario, Forecast
Business Acquisition [Line Items]
Debt Instrument, face amount									300,000,000
Scenario, Forecast | Platinum
Business Acquisition [Line Items]
Aggregate consideration									1,900,000,000
Business Acquisition, Transaction Costs									$10,000,000
Scenario, Forecast | Platinum
Business Acquisition [Line Items]
Dividends declared, Per common share										$10

Quarterly_Financial_Informatio2

Quarterly Financial Information (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues
Gross premiums written	$132,780	$200,992	$511,540	$705,260	$84,122	$182,649	$703,223	$635,418	$1,550,572	$1,605,412	$1,551,591
Net premiums written	111,769	159,713	346,407	450,347	80,784	127,241	559,109	436,813	1,068,236	1,203,947	1,102,657
(Increase) decrease in unearned premiums	144,718	99,266	-85,991	-163,813	175,981	167,476	-267,220	-165,558	-5,820	-89,321	-33,302
Net premiums earned (Note 7)	256,487	258,979	260,416	286,534	256,765	294,717	291,889	271,255	1,062,416	1,114,626	1,069,355
Net investment income	25,886	24,941	34,541	38,948	78,732	59,931	26,163	43,202	124,316	208,028	165,725
Net foreign exchange (losses) gains	-107	5,036	2,392	-1,061	1,747	488	-932	614	6,260	1,917	5,319
Equity in earnings of other ventures	4,838	9,806	7,232	4,199	6,274	7,313	3,772	5,835	26,075	23,194	23,238
Other loss	1,219	-1,169	-535	62	-173	651	-1,128	-1,709	-423	-2,359	-2,120
Net realized and unrealized gains on investments	30,475	-31,097	27,128	14,927	61,864	28,472	-69,529	14,269	41,433	35,076	163,121
Total revenues	318,798	266,496	331,174	343,609	405,209	391,572	250,235	333,466	1,260,077	1,380,482	1,424,295
Expenses
Net claims and claim expenses incurred	-12,003	69,647	81,388	58,915	-20,854	60,928	103,962	27,251	197,947	171,287	325,211
Acquisition costs	39,749	37,550	33,477	33,700	31,026	37,699	31,767	25,009	144,476	125,501	113,542
Operational expenses	55,202	46,972	45,841	42,624	57,658	44,672	42,789	45,986	190,639	191,105	179,151
Corporate expenses	10,583	3,905	3,954	4,545	3,304	4,307	21,529	4,482	22,987	33,622	16,456
Interest expense	4,289	4,290	4,292	4,293	4,297	4,298	4,300	5,034	17,164	17,929	23,097
Total expenses	97,820	162,364	168,952	144,077	75,431	151,904	204,347	107,762	573,213	539,444	657,457
Income from continuing operations before taxes	220,978	104,132	162,222	199,532	329,778	239,668	45,888	225,704	686,864	841,038	766,838
Income tax (expense) benefit	-401	-245	204	-166	-1,336	-223	-11	-122	-608	-1,692	-1,413
Income from continuing operations	220,577	103,887	162,426	199,366	328,442	239,445	45,877	225,582	686,256	839,346	765,425
Income (loss) from discontinued operations	0	0	0	0	0	-9,779	2,427	9,774	0	2,422	-16,476
Net income	220,577	103,887	162,426	199,366	328,442	229,666	48,304	235,356	686,256	841,768	748,949
Net income attributable to noncontrolling interests	-44,215	-30,477	-36,078	-42,768	-54,191	-44,331	-14,015	-38,607	-153,538	-151,144	-148,040
Net income attributable to RenaissanceRe	176,362	73,410	126,348	156,598	274,251	185,335	34,289	196,749	532,718	690,624	600,909
Dividends on preference shares	-5,595	-5,595	-5,596	-5,595	-5,595	-5,595	-7,483	-6,275	-22,381	-24,948	-34,895
Net income available to RenaissanceRe common shareholders	$170,767	$67,815	$120,752	$151,003	$268,656	$179,740	$26,806	$190,474	$510,337	$665,676	$566,014
Income from continuing operations available to RenaissanceRe common shareholders per common share – basic, in dollars per share	$4.46	$1.72	$3	$3.61	$6.14	$4.32	$0.55	$4.10	$12.77	$15.08	$11.74
Income (loss) from discontinued operations available (attributable) to RenaissanceRe common shareholders per common share – basic, in dollars per share	$0	$0	$0	$0	$0	($0.23)	$0.06	$0.22	$0	$0.06	($0.34)
Net income available to RenaissanceRe common shareholders per common share – basic (Note 13), in dollars per share	$4.46	$1.72	$3	$3.61	$6.14	$4.09	$0.61	$4.32	$12.77	$15.14	$11.40
Income from continuing operations available to RenaissanceRe common shareholders per common share – diluted, in dollars per share	$4.42	$1.70	$2.95	$3.56	$6.05	$4.23	$0.55	$4.01	$12.60	$14.82	$11.56
Income (loss) from discontinued operations available (attributable) to RenaissanceRe common shareholders per common share – diluted, in dollars per share	$0	$0	$0	$0	$0	($0.22)	$0.05	$0.22	$0	$0.05	($0.33)
Net income available to RenaissanceRe common shareholders per common share – diluted (Note 13), in dollars per share	$4.42	$1.70	$2.95	$3.56	$6.05	$4.01	$0.60	$4.23	$12.60	$14.87	$11.23
Average shares outstanding - basic (shares)	37,752	38,975	39,736	41,238	43,160	43,330	43,372	43,461	39,425	43,349	48,873
Average shares outstanding - diluted (shares)	38,145	39,433	40,395	41,903	43,769	44,135	44,243	44,290	39,968	44,128	49,603

Condensed_Consolidating_Financ2

Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries (Narrative) (Details) (RenRe North America Holdings Inc. (Subsidiary Issuer), 5.75% Senior Notes Due March 15, 2020, USD $)	0 Months Ended
	Mar. 17, 2010
RenRe North America Holdings Inc. (Subsidiary Issuer) | 5.75% Senior Notes Due March 15, 2020
Debt Instrument [Line Items]
Senior notes issuance date	17-Mar-10
5.75% Senior Notes Due March 15, 2020	$250,000,000
Senior notes interest rate	5.75%
Senior notes maturity date	15-Mar-20

Condensed_Consolidating_Financ3

Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Balance Sheet) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Assets
Total investments	$6,743,750	$6,821,712
Cash and cash equivalents	525,584	408,032	304,145	181,825
Investments in subsidiaries	0	0
Due from subsidiaries and affiliates	0	0
Premiums receivable	440,007	474,087
Prepaid reinsurance premiums	94,810	66,132
Reinsurance recoverable	66,694	101,025	192,512
Accrued investment income	26,509	34,065
Deferred acquisition costs	110,059	81,684
Receivable for investments sold	52,390	75,845
Other assets	143,747	116,549
Total assets	8,203,550	8,179,131
Liabilities
Reserve for claims and claim expenses	1,412,510	1,563,730	1,879,377
Unearned premiums	512,386	477,888
Debt	249,522	249,430
Amounts due to subsidiaries and affiliates	0	0
Reinsurance balances payable	454,580	293,022
Payable for investments purchased	203,021	193,221
Other liabilities	374,108	397,596
Total liabilities	3,206,127	3,174,887
Redeemable noncontrolling interests	1,131,708	1,099,860
Shareholders' Equity
Total shareholders’ equity	3,865,715	3,904,384	3,507,056
Total liabilities, noncontrolling interests and shareholders’ equity	8,203,550	8,179,131
RenaissanceRe Holdings Ltd. (Parent Guarantor)
Assets
Total investments	137,006	210,719
Cash and cash equivalents	5,986	8,796	6,298	10,606
Investments in subsidiaries	3,509,974	3,294,729
Due from subsidiaries and affiliates	126,548	296,752
Premiums receivable	0	0
Prepaid reinsurance premiums	0	0
Reinsurance recoverable	0	0
Accrued investment income	0	0
Deferred acquisition costs	0	0
Receivable for investments sold	10	14
Other assets	112,400	112,234
Total assets	3,891,924	3,923,244
Liabilities
Reserve for claims and claim expenses	0	0
Unearned premiums	0	0
Debt	0	0
Amounts due to subsidiaries and affiliates	6,000	0
Reinsurance balances payable	0	0
Payable for investments purchased	0	0
Other liabilities	20,209	18,860
Total liabilities	26,209	18,860
Redeemable noncontrolling interests	0	0
Shareholders' Equity
Total shareholders’ equity	3,865,715	3,904,384
Total liabilities, noncontrolling interests and shareholders’ equity	3,891,924	3,923,244
RenRe North America Holdings Inc. (Subsidiary Issuer)
Assets
Total investments	88,150	98,784
Cash and cash equivalents	1,033	4,027	1,528	4,920
Investments in subsidiaries	71,796	74,718
Due from subsidiaries and affiliates	23	0
Premiums receivable	0	0
Prepaid reinsurance premiums	0	0
Reinsurance recoverable	0	0
Accrued investment income	121	110
Deferred acquisition costs	0	0
Receivable for investments sold	0	0
Other assets	1,242	1,481
Total assets	162,365	179,120
Liabilities
Reserve for claims and claim expenses	0	0
Unearned premiums	0	0
Debt	249,522	249,430
Amounts due to subsidiaries and affiliates	233	3,173
Reinsurance balances payable	0	0
Payable for investments purchased	0	0
Other liabilities	4,013	6,953
Total liabilities	253,768	259,556
Redeemable noncontrolling interests	0	0
Shareholders' Equity
Total shareholders’ equity	-91,403	-80,436
Total liabilities, noncontrolling interests and shareholders’ equity	162,365	179,120
Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Assets
Total investments	6,518,594	6,512,209
Cash and cash equivalents	518,565	395,209	296,319	166,299
Investments in subsidiaries	0	0
Due from subsidiaries and affiliates	0	0
Premiums receivable	440,007	474,087
Prepaid reinsurance premiums	94,810	66,132
Reinsurance recoverable	66,694	101,025
Accrued investment income	26,388	33,955
Deferred acquisition costs	110,059	81,684
Receivable for investments sold	52,380	75,831
Other assets	131,563	102,834
Total assets	7,959,060	7,842,966
Liabilities
Reserve for claims and claim expenses	1,412,510	1,563,730
Unearned premiums	512,386	477,888
Debt	0	0
Amounts due to subsidiaries and affiliates	0	0
Reinsurance balances payable	454,580	293,022
Payable for investments purchased	203,021	193,221
Other liabilities	351,344	371,783
Total liabilities	2,933,841	2,899,644
Redeemable noncontrolling interests	1,131,708	1,099,860
Shareholders' Equity
Total shareholders’ equity	3,893,511	3,843,462
Total liabilities, noncontrolling interests and shareholders’ equity	7,959,060	7,842,966
Consolidating Adjustments
Assets
Total investments	0	0
Cash and cash equivalents	0	0
Investments in subsidiaries	-3,581,770	-3,369,447
Due from subsidiaries and affiliates	-126,571	-296,752
Premiums receivable	0	0
Prepaid reinsurance premiums	0	0
Reinsurance recoverable	0	0
Accrued investment income	0	0
Deferred acquisition costs	0	0
Receivable for investments sold	0	0
Other assets	-101,458	-100,000
Total assets	-3,809,799	-3,766,199
Liabilities
Reserve for claims and claim expenses	0	0
Unearned premiums	0	0
Debt	0	0
Amounts due to subsidiaries and affiliates	-6,233	-3,173
Reinsurance balances payable	0	0
Payable for investments purchased	0	0
Other liabilities	-1,458	0
Total liabilities	-7,691	-3,173
Redeemable noncontrolling interests	0	0
Shareholders' Equity
Total shareholders’ equity	-3,802,108	-3,763,026
Total liabilities, noncontrolling interests and shareholders’ equity	($3,809,799)	($3,766,199)

Condensed_Consolidating_Financ4

Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement Of Operations) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues
Net premiums earned	$256,487	$258,979	$260,416	$286,534	$256,765	$294,717	$291,889	$271,255	$1,062,416	$1,114,626	$1,069,355
Net investment income	25,886	24,941	34,541	38,948	78,732	59,931	26,163	43,202	124,316	208,028	165,725
Net foreign exchange (losses) gains	-107	5,036	2,392	-1,061	1,747	488	-932	614	6,260	1,917	5,319
Equity in earnings of other ventures	4,838	9,806	7,232	4,199	6,274	7,313	3,772	5,835	26,075	23,194	23,238
Other loss	1,219	-1,169	-535	62	-173	651	-1,128	-1,709	-423	-2,359	-2,120
Net realized and unrealized gains on investments	30,475	-31,097	27,128	14,927	61,864	28,472	-69,529	14,269	41,433	35,076	163,121
Net other-than-temporary impairments									0	0	-343
Total revenues	318,798	266,496	331,174	343,609	405,209	391,572	250,235	333,466	1,260,077	1,380,482	1,424,295
Expenses
Net claims and claim expenses incurred	-12,003	69,647	81,388	58,915	-20,854	60,928	103,962	27,251	197,947	171,287	325,211
Acquisition expenses	39,749	37,550	33,477	33,700	31,026	37,699	31,767	25,009	144,476	125,501	113,542
Operational expenses	55,202	46,972	45,841	42,624	57,658	44,672	42,789	45,986	190,639	191,105	179,151
Corporate expenses	10,583	3,905	3,954	4,545	3,304	4,307	21,529	4,482	22,987	33,622	16,456
Interest expense	4,289	4,290	4,292	4,293	4,297	4,298	4,300	5,034	17,164	17,929	23,097
Total expenses	97,820	162,364	168,952	144,077	75,431	151,904	204,347	107,762	573,213	539,444	657,457
Income (loss) before equity in net income (loss) of subsidiaries and taxes									686,864	841,038	766,838
Equity in net income (loss) of subsidiaries									0	0	0
Income from continuing operations before taxes	220,978	104,132	162,222	199,532	329,778	239,668	45,888	225,704	686,864	841,038	766,838
Income tax (expense) benefit	-401	-245	204	-166	-1,336	-223	-11	-122	-608	-1,692	-1,413
Income from continuing operations	220,577	103,887	162,426	199,366	328,442	239,445	45,877	225,582	686,256	839,346	765,425
Income from discontinued operations	0	0	0	0	0	-9,779	2,427	9,774	0	2,422	-16,476
Net income	220,577	103,887	162,426	199,366	328,442	229,666	48,304	235,356	686,256	841,768	748,949
Net income attributable to noncontrolling interests	-44,215	-30,477	-36,078	-42,768	-54,191	-44,331	-14,015	-38,607	-153,538	-151,144	-148,040
Net income attributable to RenaissanceRe	176,362	73,410	126,348	156,598	274,251	185,335	34,289	196,749	532,718	690,624	600,909
Dividends on preference shares	-5,595	-5,595	-5,596	-5,595	-5,595	-5,595	-7,483	-6,275	-22,381	-24,948	-34,895
Net income available to RenaissanceRe common shareholders	170,767	67,815	120,752	151,003	268,656	179,740	26,806	190,474	510,337	665,676	566,014
RenaissanceRe Holdings Ltd. (Parent Guarantor)
Revenues
Net premiums earned									0	0	0
Net investment income									2,706	4,213	14,195
Net foreign exchange (losses) gains									-13	-7	33
Equity in earnings of other ventures									0	0	0
Other loss									0	106	2,822
Net realized and unrealized gains on investments									83	-483	14,862
Net other-than-temporary impairments											0
Total revenues									2,776	3,829	31,912
Expenses
Net claims and claim expenses incurred									0	0	0
Acquisition expenses									0	0	0
Operational expenses									-4,890	-4,962	-5,103
Corporate expenses									20,787	31,264	14,282
Interest expense									0	734	5,875
Total expenses									15,897	27,036	15,054
Income (loss) before equity in net income (loss) of subsidiaries and taxes									-13,121	-23,207	16,858
Equity in net income (loss) of subsidiaries									545,839	713,831	584,051
Income from continuing operations before taxes									532,718	690,624	600,909
Income tax (expense) benefit									0	0	0
Income from continuing operations										690,624	600,909
Income from discontinued operations										0	0
Net income									532,718	690,624	600,909
Net income attributable to noncontrolling interests									0	0	0
Net income attributable to RenaissanceRe									532,718	690,624	600,909
Dividends on preference shares									-22,381	-24,948	-34,895
Net income available to RenaissanceRe common shareholders									510,337	665,676	566,014
RenRe North America Holdings Inc. (Subsidiary Issuer)
Revenues
Net premiums earned									0	0	0
Net investment income									1,765	488	619
Net foreign exchange (losses) gains									0	-2	0
Equity in earnings of other ventures									0	0	0
Other loss									-7	125	0
Net realized and unrealized gains on investments									9,069	1,196	1,556
Net other-than-temporary impairments											0
Total revenues									10,827	1,807	2,175
Expenses
Net claims and claim expenses incurred									0	0	0
Acquisition expenses									0	0	0
Operational expenses									7,004	7,566	7,013
Corporate expenses									238	338	273
Interest expense									14,467	14,467	14,467
Total expenses									21,709	22,371	21,753
Income (loss) before equity in net income (loss) of subsidiaries and taxes									-10,882	-20,564	-19,578
Equity in net income (loss) of subsidiaries									-4,343	2,142	1,860
Income from continuing operations before taxes									-15,225	-18,422	-17,718
Income tax (expense) benefit									4,064	-1,558	-499
Income from continuing operations										-19,980	-18,217
Income from discontinued operations										2,422	-16,476
Net income									-11,161	-17,558	-34,693
Net income attributable to noncontrolling interests									0	0	0
Net income attributable to RenaissanceRe									-11,161	-17,558	-34,693
Dividends on preference shares									0	0	0
Net income available to RenaissanceRe common shareholders									-11,161	-17,558	-34,693
Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Revenues
Net premiums earned									1,062,416	1,114,626	1,069,355
Net investment income									123,582	209,105	150,911
Net foreign exchange (losses) gains									6,273	1,926	5,286
Equity in earnings of other ventures									26,075	23,194	23,238
Other loss									-416	-2,590	-4,942
Net realized and unrealized gains on investments									32,281	34,363	146,703
Net other-than-temporary impairments											-343
Total revenues									1,250,211	1,380,624	1,390,208
Expenses
Net claims and claim expenses incurred									197,947	171,287	325,211
Acquisition expenses									144,476	125,501	113,542
Operational expenses									188,857	189,117	177,241
Corporate expenses									1,962	2,020	1,901
Interest expense									2,697	2,728	2,755
Total expenses									535,939	490,653	620,650
Income (loss) before equity in net income (loss) of subsidiaries and taxes									714,272	889,971	769,558
Equity in net income (loss) of subsidiaries									0	0	0
Income from continuing operations before taxes									714,272	889,971	769,558
Income tax (expense) benefit									-4,672	-134	-914
Income from continuing operations										889,837	768,644
Income from discontinued operations										0	0
Net income									709,600	889,837	768,644
Net income attributable to noncontrolling interests									-153,538	-151,144	-148,040
Net income attributable to RenaissanceRe									556,062	738,693	620,604
Dividends on preference shares									0	0	0
Net income available to RenaissanceRe common shareholders									556,062	738,693	620,604
Consolidating Adjustments
Revenues
Net premiums earned									0	0	0
Net investment income									-3,737	-5,778	0
Net foreign exchange (losses) gains									0	0	0
Equity in earnings of other ventures									0	0	0
Other loss									0	0	0
Net realized and unrealized gains on investments									0	0	0
Net other-than-temporary impairments											0
Total revenues									-3,737	-5,778	0
Expenses
Net claims and claim expenses incurred									0	0	0
Acquisition expenses									0	0	0
Operational expenses									-332	-616	0
Corporate expenses									0	0	0
Interest expense									0	0	0
Total expenses									-332	-616	0
Income (loss) before equity in net income (loss) of subsidiaries and taxes									-3,405	-5,162	0
Equity in net income (loss) of subsidiaries									-541,496	-715,973	-585,911
Income from continuing operations before taxes									-544,901	-721,135	-585,911
Income tax (expense) benefit									0	0	0
Income from continuing operations										-721,135	-585,911
Income from discontinued operations										0	0
Net income									-544,901	-721,135	-585,911
Net income attributable to noncontrolling interests									0	0	0
Net income attributable to RenaissanceRe									-544,901	-721,135	-585,911
Dividends on preference shares									0	0	0
Net income available to RenaissanceRe common shareholders									($544,901)	($721,135)	($585,911)

Condensed_Consolidating_Financ5

Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement of Comprehensive Income (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	$220,577	$103,887	$162,426	$199,366	$328,442	$229,666	$48,304	$235,356	$686,256	$841,768	$748,949
Change in net unrealized gains on investments									-715	-9,491	1,914
Portion recognized in other comprehensive income (loss), before taxes									0	0	52
Comprehensive income									685,541	832,277	750,811
Net income attributable to noncontrolling interests									-153,538	-151,144	-148,040
Comprehensive income attributable to noncontrolling interests									-153,538	-151,144	-148,040
Comprehensive income attributable to RenaissanceRe									532,003	681,133	602,771
RenaissanceRe Holdings Ltd. (Parent Guarantor)
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									532,718	690,624	600,909
Change in net unrealized gains on investments									0	0	0
Portion recognized in other comprehensive income (loss), before taxes											0
Comprehensive income									532,718	690,624	600,909
Net income attributable to noncontrolling interests									0	0	0
Comprehensive income attributable to noncontrolling interests									0	0	0
Comprehensive income attributable to RenaissanceRe									532,718	690,624	600,909
RenRe North America Holdings Inc. (Subsidiary Issuer)
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									-11,161	-17,558	-34,693
Change in net unrealized gains on investments									0	0	0
Portion recognized in other comprehensive income (loss), before taxes											0
Comprehensive income									-11,161	-17,558	-34,693
Net income attributable to noncontrolling interests									0	0	0
Comprehensive income attributable to noncontrolling interests									0	0	0
Comprehensive income attributable to RenaissanceRe									-11,161	-17,558	-34,693
Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									709,600	889,837	768,644
Change in net unrealized gains on investments									-715	-9,491	1,914
Portion recognized in other comprehensive income (loss), before taxes											52
Comprehensive income									708,885	880,346	770,506
Net income attributable to noncontrolling interests									-153,538	-151,144	-148,040
Comprehensive income attributable to noncontrolling interests									-153,538	-151,144	-148,040
Comprehensive income attributable to RenaissanceRe									555,347	729,202	622,466
Consolidating Adjustments
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									-544,901	-721,135	-585,911
Change in net unrealized gains on investments									0	0	0
Portion recognized in other comprehensive income (loss), before taxes											0
Comprehensive income									-544,901	-721,135	-585,911
Net income attributable to noncontrolling interests									0	0	0
Comprehensive income attributable to noncontrolling interests									0	0	0
Comprehensive income attributable to RenaissanceRe									($544,901)	($721,135)	($585,911)

Condensed_Consolidating_Financ6

Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement Of Cash Flows) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows provided by (used in) operating activities:
Net cash provided by (used in) operating activities	$660,657,000	$795,721,000	$716,929,000
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	7,682,573,000	8,251,405,000	8,192,867,000
Purchases of fixed maturity investments trading	-7,639,178,000	-8,466,467,000	-8,536,238,000
Proceeds from sales and maturities of fixed maturity investments available for sale	7,088,000	45,178,000	65,168,000
Net (purchases) sales of equity investments trading	-20,003,000	-33,055,000	0
Net (purchases) sales of short term investments	45,023,000	-246,971,000	68,777,000
Net sales of other investments	59,120,000	76,214,000	150,828,000
Net purchases of investments in other ventures	1,030,000	-4,000,000	0
Net sales (purchases) of other assets	6,000,000	2,181,000	-4,079,000
Dividends and return of capital from subsidiaries	0	0	0
Contributions to subsidiaries	0	0	0
Due (from) to subsidiary	0	0	0
Net proceeds (payments) related to sale of discontinued operations	0	60,000,000	-9,000,000
Net cash provided by (used in) investing activities	141,653,000	-315,515,000	-71,677,000
Cash flows provided by (used in) financing activities
Dividends paid – RenaissanceRe common shares	-45,912,000	-49,267,000	-53,356,000
Dividends paid – preference shares	-22,381,000	-24,948,000	-34,895,000
RenaissanceRe common share repurchases	-514,678,000	-207,410,000	-463,309,000
Net repayment of debt	0	-102,436,000	-1,937,000
Redemption of preference shares		-125,000,000	-150,000,000
Contribution of capital from parent		0
Net third party redeemable noncontrolling interest share transactions	-111,707,000	-5,750,000	164,927,000
Net cash used in financing activities	-694,678,000	-398,955,000	-538,570,000
Effect of exchange rate changes on foreign currency cash	9,920,000	1,423,000	1,692,000
Net increase in cash and cash equivalents	117,552,000	82,674,000	108,374,000
Net decrease in cash and cash equivalents of discontinued operations	0	21,213,000	13,946,000
Cash and cash equivalents, beginning of period	408,032,000	304,145,000	181,825,000
Cash and cash equivalents, end of period	525,584,000	408,032,000	304,145,000
RenaissanceRe Holdings Ltd. (Parent Guarantor)
Cash flows provided by (used in) operating activities:
Net cash provided by (used in) operating activities	429,000	-37,966,000	128,567,000
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	88,273,000	880,749,000	744,211,000
Purchases of fixed maturity investments trading	-88,341,000	-491,768,000	-692,783,000
Proceeds from sales and maturities of fixed maturity investments available for sale	0	0	0
Net (purchases) sales of equity investments trading	0	0
Net (purchases) sales of short term investments	73,717,000	21,217,000	-80,485,000
Net sales of other investments	0	0	0
Net purchases of investments in other ventures	0	0
Net sales (purchases) of other assets	0	0	0
Dividends and return of capital from subsidiaries	1,259,224,000	504,241,000	979,311,000
Contributions to subsidiaries	-759,456,000	-500,652,000	-366,210,000
Due (from) to subsidiary	6,315,000	17,446,000	-15,359,000
Net proceeds (payments) related to sale of discontinued operations		0	0
Net cash provided by (used in) investing activities	579,732,000	431,233,000	568,685,000
Cash flows provided by (used in) financing activities
Dividends paid – RenaissanceRe common shares	-45,912,000	-49,267,000	-53,356,000
Dividends paid – preference shares	-22,381,000	-24,948,000	-34,895,000
RenaissanceRe common share repurchases	-514,678,000	-207,410,000	-463,309,000
Net repayment of debt	0	-100,000,000	0
Redemption of preference shares		-125,000,000	-150,000,000
Contribution of capital from parent		0
Net third party redeemable noncontrolling interest share transactions	0	0	0
Net cash used in financing activities	-582,971,000	-390,769,000	-701,560,000
Effect of exchange rate changes on foreign currency cash	0	0	0
Net increase in cash and cash equivalents	-2,810,000	2,498,000	-4,308,000
Net decrease in cash and cash equivalents of discontinued operations		0	0
Cash and cash equivalents, beginning of period	8,796,000	6,298,000	10,606,000
Cash and cash equivalents, end of period	5,986,000	8,796,000	6,298,000
RenRe North America Holdings Inc. (Subsidiary Issuer)
Cash flows provided by (used in) operating activities:
Net cash provided by (used in) operating activities	-18,114,000	-7,583,000	-10,376,000
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	20,487,000	185,143,000	140,626,000
Purchases of fixed maturity investments trading	-14,969,000	-160,422,000	-73,800,000
Proceeds from sales and maturities of fixed maturity investments available for sale	0	0	0
Net (purchases) sales of equity investments trading	13,761,000	-81,437,000
Net (purchases) sales of short term investments	225,000	9,399,000	-10,624,000
Net sales of other investments	0	0	0
Net purchases of investments in other ventures	0	0
Net sales (purchases) of other assets	0	0	0
Dividends and return of capital from subsidiaries	11,204,000	83,593,000	9,541,000
Contributions to subsidiaries	-12,625,000	-38,117,000	-50,000,000
Due (from) to subsidiary	-2,963,000	-3,761,000	241,000
Net proceeds (payments) related to sale of discontinued operations		0	-9,000,000
Net cash provided by (used in) investing activities	15,120,000	-5,602,000	6,984,000
Cash flows provided by (used in) financing activities
Dividends paid – RenaissanceRe common shares	0	0	0
Dividends paid – preference shares	0	0	0
RenaissanceRe common share repurchases	0	0	0
Net repayment of debt		0	0
Redemption of preference shares		0	0
Contribution of capital from parent		15,684,000
Net third party redeemable noncontrolling interest share transactions	0	0	0
Net cash used in financing activities	0	15,684,000	0
Effect of exchange rate changes on foreign currency cash	0	0	0
Net increase in cash and cash equivalents	-2,994,000	2,499,000	-3,392,000
Net decrease in cash and cash equivalents of discontinued operations		0	0
Cash and cash equivalents, beginning of period	4,027,000	1,528,000	4,920,000
Cash and cash equivalents, end of period	1,033,000	4,027,000	1,528,000
Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Cash flows provided by (used in) operating activities:
Net cash provided by (used in) operating activities	678,342,000	841,270,000	598,738,000
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	7,573,813,000	7,185,513,000	7,308,030,000
Purchases of fixed maturity investments trading	-7,535,868,000	-7,814,277,000	-7,769,655,000
Proceeds from sales and maturities of fixed maturity investments available for sale	7,088,000	45,178,000	65,168,000
Net (purchases) sales of equity investments trading	-33,764,000	48,382,000
Net (purchases) sales of short term investments	-28,919,000	-277,587,000	159,886,000
Net sales of other investments	59,120,000	76,214,000	150,828,000
Net purchases of investments in other ventures	1,030,000	-4,000,000
Net sales (purchases) of other assets	6,000,000	2,181,000	-4,079,000
Dividends and return of capital from subsidiaries	-1,270,428,000	-587,834,000	-988,852,000
Contributions to subsidiaries	772,081,000	538,769,000	416,210,000
Due (from) to subsidiary	-3,352,000	-13,685,000	15,118,000
Net proceeds (payments) related to sale of discontinued operations		60,000,000	0
Net cash provided by (used in) investing activities	-453,199,000	-741,146,000	-647,346,000
Cash flows provided by (used in) financing activities
Dividends paid – RenaissanceRe common shares	0	0	0
Dividends paid – preference shares	0	0	0
RenaissanceRe common share repurchases	0	0	0
Net repayment of debt		-2,436,000	-1,937,000
Redemption of preference shares		0	0
Contribution of capital from parent		-15,684,000
Net third party redeemable noncontrolling interest share transactions	-111,707,000	-5,750,000	164,927,000
Net cash used in financing activities	-111,707,000	-23,870,000	162,990,000
Effect of exchange rate changes on foreign currency cash	9,920,000	1,423,000	1,692,000
Net increase in cash and cash equivalents	123,356,000	77,677,000	116,074,000
Net decrease in cash and cash equivalents of discontinued operations		21,213,000	13,946,000
Cash and cash equivalents, beginning of period	395,209,000	296,319,000	166,299,000
Cash and cash equivalents, end of period	518,565,000	395,209,000	296,319,000
Series C Preferred Stock
Cash flows provided by (used in) financing activities
Redemption of preference shares	0	-125,000,000	0
Series C Preferred Stock | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Cash flows provided by (used in) financing activities
Redemption of preference shares	0	-125,000,000	0
Series D Preferred Stock
Cash flows provided by (used in) financing activities
Redemption of preference shares	0	-150,000,000	-150,000,000
Series D Preferred Stock | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Cash flows provided by (used in) financing activities
Redemption of preference shares	0	-150,000,000	-150,000,000
Series D Preferred Stock | RenRe North America Holdings Inc. (Subsidiary Issuer)
Cash flows provided by (used in) financing activities
Redemption of preference shares		0
Series D Preferred Stock | Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Cash flows provided by (used in) financing activities
Redemption of preference shares		0
Series E Preferred Stock
Cash flows provided by (used in) financing activities
Issuance of 5.375% Series E preference shares, net of expenses	0	265,856,000	0
Series E Preferred Stock | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Cash flows provided by (used in) financing activities
Issuance of 5.375% Series E preference shares, net of expenses	0	265,856,000	0
Series E Preferred Stock | RenRe North America Holdings Inc. (Subsidiary Issuer)
Cash flows provided by (used in) financing activities
Issuance of 5.375% Series E preference shares, net of expenses		0
Series E Preferred Stock | Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Cash flows provided by (used in) financing activities
Issuance of 5.375% Series E preference shares, net of expenses		$0

Subsequent_Events_Details

Subsequent Events (Details) (USD $)

1 Months Ended

2 Months Ended

3 Months Ended

In Millions, unless otherwise specified

Jan. 31, 2014

Jan. 31, 2013

Jan. 31, 2015

Mar. 31, 2015

Mar. 31, 2015

Dec. 31, 2014

Jul. 01, 2014

Jun. 30, 2014

Jan. 01, 2014

Dec. 31, 2013

Jan. 02, 2013

Dec. 31, 2012

Feb. 28, 2014

Jan. 01, 2015

DaVinciRe

Subsequent Event [Line Items]

Redeemable noncontrolling interest, ownership percentage

23.40%

23.40%

26.50%

26.50%

27.30%

32.90%

30.80%

Redeemable Noncontrolling Interest | DaVinciRe

Subsequent Event [Line Items]

Redeemable noncontrolling interest, net redemptions

$300

$150

Redeemable noncontrolling interest, Reserve holdback

20.5

60

Subsequent Event | DaVinciRe

Subsequent Event [Line Items]

Redeemable noncontrolling interest, ownership percentage

26.30%

Subsequent Event | Upsilon RFO | Primary Beneficiary

Subsequent Event [Line Items]

Capital returned to investors

317.5

35.3

352.8

Subsequent Event | Redeemable Noncontrolling Interest | DaVinciRe

Subsequent Event [Line Items]

Redeemable noncontrolling interest, net redemptions

225

Redeemable noncontrolling interest, Reserve holdback

$45

Schedule_I_Summary_of_Investme1

Schedule I. Summary of Investments Other Than Investments in Related Parties (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Market Value	$6,743,750
Amount at which shown in the Balance Sheet	6,743,750
Short-term investments	1,013,222	1,044,779
Equity investments trading	322,098	254,776
Other investments	504,147	573,264
Investments in other ventures, under equity method	120,713	105,616
U.S. treasuries
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	1,672,441
Market Value	1,671,471
Amount at which shown in the Balance Sheet	1,671,471
Agencies
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	96,271
Market Value	96,208
Amount at which shown in the Balance Sheet	96,208
Non-U.S. government (Sovereign Debt)
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	287,856
Market Value	280,651
Amount at which shown in the Balance Sheet	280,651
Non-U.S. government-backed corporate
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	146,691
Market Value	146,467
Amount at which shown in the Balance Sheet	146,467
Corporate
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	1,611,172
Market Value	1,610,442
Amount at which shown in the Balance Sheet	1,610,442
Agency mortgage-backed
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	315,911
Market Value	316,620
Amount at which shown in the Balance Sheet	316,620
Non-agency mortgage-backed
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	237,891
Market Value	253,050
Amount at which shown in the Balance Sheet	253,050
Commercial mortgage-backed
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	377,792
Market Value	381,051
Amount at which shown in the Balance Sheet	381,051
Asset-backed
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	27,360
Market Value	27,610
Amount at which shown in the Balance Sheet	27,610
Fixed maturity investments
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Amortized Cost	4,773,385
Market Value	4,783,570
Amount at which shown in the Balance Sheet	$4,783,570

Schedule_II_Condensed_Financia1

Schedule II. Condensed Financial Information Of Registrant (Balance Sheets) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, except Per Share data, unless otherwise specified
Condensed Financial Statements, Captions [Line Items]
Preference Shares, Par Value (In dollars per share)	$1	$1
Assets
Short-term investments	$1,013,222	$1,044,779
Cash and cash equivalents	525,584	408,032	304,145	181,825
Investments in subsidiaries	0	0
Accrued investment income	26,509	34,065
Receivable for investments sold	52,390	75,845
Other assets	135,845	108,438
Total assets	8,203,550	8,179,131
Liabilities
Contributions due to subsidiaries	0	0
Other liabilities	374,108	397,596
Total liabilities	3,206,127	3,174,887
Shareholders' Equity
Preference shares: $1.00 par value – 16,000,000 shares issued and outstanding at December 31, 2014 (December 31, 2013 – 16,000,000)	400,000	400,000
Common shares: $1.00 par value – 38,441,972 shares issued and outstanding at December 31, 2014 (December 31, 2013 – 43,646,436)	38,442	43,646
Accumulated other comprehensive income	3,416	4,131	13,622
Retained earnings	3,423,857	3,456,607
Total shareholders’ equity	3,865,715	3,904,384	3,507,056
Total liabilities, noncontrolling interests and shareholders’ equity	8,203,550	8,179,131
Parent Company
Condensed Financial Statements, Captions [Line Items]
Preference Shares, Par Value (In dollars per share)	$1	$1
Assets
Short-term investments	137,006	210,719
Cash and cash equivalents	5,986	8,796	6,298	10,606
Investments in subsidiaries	3,509,974	3,294,729
Due from subsidiaries	10,164	16,479
Dividends due from subsidiaries	116,384	280,273
Accrued investment income	0	0
Receivable for investments sold	10	14
Other assets	112,400	112,234
Total assets	3,891,924	3,923,244
Liabilities
Contributions due to subsidiaries	6,000	0
Other liabilities	20,209	18,860
Total liabilities	26,209	18,860
Shareholders' Equity
Preference shares: $1.00 par value – 16,000,000 shares issued and outstanding at December 31, 2014 (December 31, 2013 – 16,000,000)	400,000	400,000
Common shares: $1.00 par value – 38,441,972 shares issued and outstanding at December 31, 2014 (December 31, 2013 – 43,646,436)	38,442	43,646
Accumulated other comprehensive income	3,416	4,131
Retained earnings	3,423,857	3,456,607
Total shareholders’ equity	3,865,715	3,904,384
Total liabilities, noncontrolling interests and shareholders’ equity	$3,891,924	$3,923,244

Schedule_II_Condensed_Financia2

Schedule II. Condensed Financial Information Of Registrant (Balance Sheets Parenthetical) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Preference Shares, Par Value (In dollars per share)	$1	$1
Preference Shares, Shares issued (In shares)	16,000,000	16,000,000
Preference shares, Shares outstanding (In shares)	16,000,000	16,000,000
Common Shares, Par Value (In dollars per share)	$1	$1
Common Shares, Shares issued (In shares)	38,441,972	43,646,436
Common Shares, Shares outstanding (In shares)	38,441,972	43,646,436
Parent Company
Condensed Financial Statements, Captions [Line Items]
Preference Shares, Par Value (In dollars per share)	$1	$1
Preference Shares, Shares issued (In shares)	16,000,000	16,000,000
Preference shares, Shares outstanding (In shares)	16,000,000	16,000,000
Common Shares, Par Value (In dollars per share)	$1	$1
Common Shares, Shares issued (In shares)	38,441,972	43,646,436
Common Shares, Shares outstanding (In shares)	38,441,972	43,646,436

Schedule_II_Condensed_Financia3

Schedule II. Condensed Financial Information Of Registrant (Statements of Operations) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues
Net investment income	$25,886	$24,941	$34,541	$38,948	$78,732	$59,931	$26,163	$43,202	$124,316	$208,028	$165,725
Net foreign exchange gains	-107	5,036	2,392	-1,061	1,747	488	-932	614	6,260	1,917	5,319
Other income (loss)	1,219	-1,169	-535	62	-173	651	-1,128	-1,709	-423	-2,359	-2,120
Net realized and unrealized gains on investments	30,475	-31,097	27,128	14,927	61,864	28,472	-69,529	14,269	41,433	35,076	163,121
Total revenues	318,798	266,496	331,174	343,609	405,209	391,572	250,235	333,466	1,260,077	1,380,482	1,424,295
Expenses
Interest expense	4,289	4,290	4,292	4,293	4,297	4,298	4,300	5,034	17,164	17,929	23,097
Operational expenses	55,202	46,972	45,841	42,624	57,658	44,672	42,789	45,986	190,639	191,105	179,151
Operating and corporate expenses	10,583	3,905	3,954	4,545	3,304	4,307	21,529	4,482	22,987	33,622	16,456
Total expenses	97,820	162,364	168,952	144,077	75,431	151,904	204,347	107,762	573,213	539,444	657,457
Income (loss) before equity in net income (loss) of subsidiaries and taxes									686,864	841,038	766,838
Equity in net income (loss) of subsidiaries									0	0	0
Net income attributable to RenaissanceRe	176,362	73,410	126,348	156,598	274,251	185,335	34,289	196,749	532,718	690,624	600,909
Dividends on preference shares	-5,595	-5,595	-5,596	-5,595	-5,595	-5,595	-7,483	-6,275	-22,381	-24,948	-34,895
Net income available to RenaissanceRe common shareholders	170,767	67,815	120,752	151,003	268,656	179,740	26,806	190,474	510,337	665,676	566,014
Parent Company
Revenues
Net investment income									2,706	4,213	14,195
Net foreign exchange gains									-13	-7	33
Other income (loss)									0	106	2,822
Net realized and unrealized gains on investments									83	-483	14,862
Total revenues									2,776	3,829	31,912
Expenses
Interest expense									0	734	5,875
Operational expenses									-4,890	-4,962	-5,103
Operating and corporate expenses									20,787	31,264	14,282
Total expenses									15,897	27,036	15,054
Income (loss) before equity in net income (loss) of subsidiaries and taxes									-13,121	-23,207	16,858
Equity in net income (loss) of subsidiaries									545,839	713,831	584,051
Net income attributable to RenaissanceRe									532,718	690,624	600,909
Dividends on preference shares									-22,381	-24,948	-34,895
Net income available to RenaissanceRe common shareholders									$510,337	$665,676	$566,014

Schedule_II_Condensed_Financia4

Schedule II. Condensed Financial Information Of Registrant (Comprehensive Income (Loss)) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net income	$220,577	$103,887	$162,426	$199,366	$328,442	$229,666	$48,304	$235,356	$686,256	$841,768	$748,949
Comprehensive income (loss) attributable to RenaissanceRe									532,003	681,133	602,771
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net income									532,718	690,624	600,909
Comprehensive income (loss) attributable to RenaissanceRe									$532,718	$690,624	$600,909

Schedule_II_Condensed_Financia5

Schedule II. Condensed Financial Information Of Registrant (Statements of Cash Flows) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows provided by (used in) operating activities:
Net income attributable to RenaissanceRe	$532,718,000	$690,624,000	$600,909,000
Less: equity in net (income) loss of subsidiaries	0	0	0
Adjustments to reconcile net income to net cash provided by operating activities
Net unrealized losses (gains) included in net investment income	1,393,000	-75,789,000	-38,207,000
Net unrealized losses (gains) included in other loss	1,612,000	12,782,000	-330,000
Net realized and unrealized gains on investments	-41,433,000	-35,076,000	-163,121,000
Other	-71,146,000	159,892,000	-8,074,000
Net cash provided by operating activities	660,657,000	795,721,000	716,929,000
Cash flows provided by (used in) investing activities
Proceeds from maturities and sales of fixed maturity investments trading	7,682,573,000	8,251,405,000	8,192,867,000
Purchases of fixed maturity investments trading	-7,639,178,000	-8,466,467,000	-8,536,238,000
Net (purchases) sales of short term investments	45,023,000	-246,971,000	68,777,000
Contributions to subsidiaries	0	0	0
Net cash provided by (used in) investing activities	141,653,000	-315,515,000	-71,677,000
Cash flows used in financing activities
Dividends paid – RenaissanceRe common shares	-45,912,000	-49,267,000	-53,356,000
Dividends paid – preference shares	-22,381,000	-24,948,000	-34,895,000
RenaissanceRe common share repurchases	-514,678,000	-207,410,000	-463,309,000
Redemption of preference shares		-125,000,000	-150,000,000
Net repayment of debt	0	-102,436,000	-1,937,000
Net cash used in financing activities	-694,678,000	-398,955,000	-538,570,000
Net increase (decrease) in cash and cash equivalents	117,552,000	82,674,000	108,374,000
Cash and cash equivalents, beginning of period	408,032,000	304,145,000	181,825,000
Cash and cash equivalents, end of period	525,584,000	408,032,000	304,145,000
Parent Company
Cash flows provided by (used in) operating activities:
Net income attributable to RenaissanceRe	532,718,000	690,624,000	600,909,000
Less: equity in net (income) loss of subsidiaries	-545,839,000	-713,831,000	-584,051,000
Income (loss) before equity in net income (loss) of subsidiaries and taxes	-13,121,000	-23,207,000	16,858,000
Adjustments to reconcile net income to net cash provided by operating activities
Net unrealized losses (gains) included in net investment income	0	0	348,000
Net unrealized losses (gains) included in other loss	0	-20,000	-193,000
Net realized and unrealized gains on investments	-83,000	483,000	-14,862,000
Other	13,633,000	-15,222,000	126,416,000
Net cash provided by operating activities	429,000	-37,966,000	128,567,000
Cash flows provided by (used in) investing activities
Proceeds from maturities and sales of fixed maturity investments trading	88,273,000	880,749,000	744,211,000
Purchases of fixed maturity investments trading	-88,341,000	-491,768,000	-692,783,000
Net (purchases) sales of short term investments	73,717,000	21,217,000	-80,485,000
Dividends and return of capital from subsidiaries	1,259,224,000	504,241,000	979,311,000
Contributions to subsidiaries	-759,456,000	-500,652,000	-366,210,000
Due to (from) subsidiary	6,315,000	17,446,000	-15,359,000
Net cash provided by (used in) investing activities	579,732,000	431,233,000	568,685,000
Cash flows used in financing activities
Dividends paid – RenaissanceRe common shares	-45,912,000	-49,267,000	-53,356,000
Dividends paid – preference shares	-22,381,000	-24,948,000	-34,895,000
RenaissanceRe common share repurchases	-514,678,000	-207,410,000	-463,309,000
Redemption of preference shares		-125,000,000	-150,000,000
Net repayment of debt	0	-100,000,000	0
Net cash used in financing activities	-582,971,000	-390,769,000	-701,560,000
Net increase (decrease) in cash and cash equivalents	-2,810,000	2,498,000	-4,308,000
Cash and cash equivalents, beginning of period	8,796,000	6,298,000	10,606,000
Cash and cash equivalents, end of period	5,986,000	8,796,000	6,298,000
Series C Preferred Stock
Cash flows used in financing activities
Redemption of preference shares	0	-125,000,000	0
Series C Preferred Stock | Parent Company
Cash flows used in financing activities
Redemption of preference shares	0	-125,000,000	0
Series D Preferred Stock
Cash flows used in financing activities
Redemption of preference shares	0	-150,000,000	-150,000,000
Series D Preferred Stock | Parent Company
Cash flows used in financing activities
Redemption of preference shares	0	-150,000,000	-150,000,000
Series E Preferred Stock
Cash flows used in financing activities
Issuance of 5.375% Series E preference shares, net of expenses	0	265,856,000	0
Series E Preferred Stock | Parent Company
Cash flows used in financing activities
Issuance of 5.375% Series E preference shares, net of expenses	$0	$265,856,000	$0

Schedule_III_Supplementary_Ins1

Schedule III. Supplementary Insurance Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	$110,059	$81,684	$52,622
Future Policy Benefits, Losses, Claims and Loss Expenses	1,412,510	1,563,730	1,879,377
Unearned Premiums	512,386	477,888	399,517
Premium Revenue	1,062,416	1,114,626	1,069,355
Net Investment Income	124,316	208,028	165,725
Benefits, Claims, Losses and Settlement Expenses	197,947	171,287	325,211
Amortization of Deferred Policy Acquisition Costs	144,476	125,501	113,542
Other Operating Expenses	190,639	191,105	179,151
Net Written Premiums	1,068,236	1,203,947	1,102,657
Catastrophe Reinsurance
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	28,057	37,889	28,306
Future Policy Benefits, Losses, Claims and Loss Expenses	542,667	780,987	1,184,258
Unearned Premiums	222,864	279,465	261,456
Premium Revenue	590,845	723,705	781,738
Net Investment Income	0	0	0
Benefits, Claims, Losses and Settlement Expenses	1,757	7,908	165,209
Amortization of Deferred Policy Acquisition Costs	43,161	49,161	66,665
Other Operating Expenses	95,851	108,130	103,811
Net Written Premiums	541,608	753,078	766,035
Specialty Reinsurance
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	58,758	26,727	15,010
Future Policy Benefits, Losses, Claims and Loss Expenses	543,710	506,268	478,313
Unearned Premiums	184,054	115,278	84,058
Premium Revenue	253,537	214,306	164,685
Net Investment Income	0	0	0
Benefits, Claims, Losses and Settlement Expenses	88,502	67,236	76,813
Amortization of Deferred Policy Acquisition Costs	60,936	41,538	23,826
Other Operating Expenses	43,370	31,780	29,124
Net Written Premiums	295,855	248,562	201,552
Lloyd's
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	23,244	17,068	9,306
Future Policy Benefits, Losses, Claims and Loss Expenses	284,447	218,367	149,470
Unearned Premiums	105,468	83,145	54,003
Premium Revenue	217,666	176,029	122,968
Net Investment Income	0	0	0
Benefits, Claims, Losses and Settlement Expenses	113,825	95,693	80,242
Amortization of Deferred Policy Acquisition Costs	46,927	34,823	22,864
Other Operating Expenses	51,115	50,540	45,680
Net Written Premiums	230,429	201,697	135,131
Other
Supplementary Insurance Information, by Segment [Line Items]
Deferred Policy Acquisition Costs	0	0	0
Future Policy Benefits, Losses, Claims and Loss Expenses	41,686	58,108	67,336
Unearned Premiums	0	0	0
Premium Revenue	368	586	-36
Net Investment Income	124,316	208,028	165,725
Benefits, Claims, Losses and Settlement Expenses	-6,137	450	2,947
Amortization of Deferred Policy Acquisition Costs	-6,548	-21	187
Other Operating Expenses	303	655	536
Net Written Premiums	$344	$610	($61)

Schedule_IV_Supplemental_Sched1

Schedule IV. Supplemental Schedule of Reinsurance Premiums (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Abstract]
Gross Amounts									$66,027	$44,530	$34,028
Ceded to Other Companies									453,658	412,415	430,374
Assumed									1,450,047	1,482,511	1,465,701
Net premiums earned (Note 7)	$256,487	$258,979	$260,416	$286,534	$256,765	$294,717	$291,889	$271,255	$1,062,416	$1,114,626	$1,069,355
Percentage of Amount Assumed to Net									136.00%	133.00%	137.00%

Schedule_VI_Supplementary_Insu1

Schedule VI. Supplementary Insurance Information Concerning Property-Casualty Insurance Operations (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Current year	$341,745	$315,241	$483,180
Prior years	-143,798	-143,954	-157,969
Consolidated Subsidiaries
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Deferred Policy Acquisition Costs	110,059	81,684	52,622
Reserves for Unpaid Claims and Claim Adjustment Expenses	1,412,510	1,563,730	1,879,377
Discount, if any, Deducted	0	0	0
Unearned Premiums	512,386	477,888	399,517
Earned Premiums	1,062,416	1,114,626	1,069,355
Net Investment Income	124,316	208,028	165,725
Current year	341,745	315,241	483,180
Prior years	-143,798	-143,954	-157,969
Amortization of Deferred Policy Acquisition Costs	144,476	125,501	113,542
Paid Claims and Claims Adjustment Expenses	314,836	395,447	226,671
Net Premiums Written	$1,068,236	$1,203,947	$1,102,657