Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement Of Cash Flows) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows provided by (used in) operating activities:
Net cash provided by operating activities	$ 469,829	$ 414,737	$ 660,657
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	8,102,514	9,481,742	7,682,573
Purchases of fixed maturity investments trading	(8,282,720)	(9,683,068)	(7,639,178)
Proceeds from sales and maturities of fixed maturity investments available for sale	17,692	8,688	7,088
Net (purchases) sales of equity investments trading	184,788	(147,558)	(20,003)
Net (purchases) sales of short term investments	(118,617)	669,116	45,023
Net (purchases) sales of other investments	(68,589)	15,843	59,120
Net purchases of investments in other ventures	0	(10,150)	1,030
Net sales of other assets	400	4,500	6,000
Dividends and return of capital from subsidiaries	0	0	0
Contributions to subsidiaries	0	0	0
Due (from) to subsidiary	0	0	0
Net purchase of Platinum	0	(678,152)	0
Net cash (used in) provided by investing activities	(164,532)	(339,039)	141,653
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(51,583)	(53,967)	(45,912)
Dividends paid – preference shares	(22,381)	(22,381)	(22,381)
RenaissanceRe common share repurchases	(309,434)	(259,874)	(514,678)
Issuance of debt	0	445,589	0
Net third party redeemable noncontrolling interest share transactions	(2,990)	(193,032)	(111,707)
Net cash used in financing activities	(386,388)	(83,665)	(694,678)
Effect of exchange rate changes on foreign currency cash	(4,637)	(10,732)	9,920
Net (decrease) increase in cash and cash equivalents	(85,728)	(18,699)	117,552
Cash and cash equivalents, beginning of period	506,885	525,584	408,032
Cash and cash equivalents, end of period	421,157	506,885	525,584
RenaissanceRe Holdings Ltd. (Parent Guarantor)
Cash flows provided by (used in) operating activities:
Net cash provided by operating activities	(18,452)	(39,213)	429
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	314,568	63,824	88,273
Purchases of fixed maturity investments trading	(336,345)	(161,183)	(88,341)
Net (purchases) sales of short term investments	(111,814)	(116,461)	73,717
Dividends and return of capital from subsidiaries	617,239	1,584,624	1,259,224
Contributions to subsidiaries	(108,674)	(294,733)	(759,456)
Net purchase of Platinum	0	(904,433)	0
Net cash (used in) provided by investing activities	398,732	379,634	579,732
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(51,583)	(53,967)	(45,912)
Dividends paid – preference shares	(22,381)	(22,381)	(22,381)
RenaissanceRe common share repurchases	(309,434)	(259,874)	(514,678)
Net cash used in financing activities	(383,398)	(336,222)	(582,971)
Net (decrease) increase in cash and cash equivalents	(3,118)	4,199	(2,810)
Cash and cash equivalents, beginning of period	10,185	5,986	8,796
Cash and cash equivalents, end of period	7,067	10,185	5,986
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Cash flows provided by (used in) operating activities:
Net cash provided by operating activities	(18,452)	(39,213)	429
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	314,568	63,824	88,273
Purchases of fixed maturity investments trading	(336,345)	(161,183)	(88,341)
Proceeds from sales and maturities of fixed maturity investments available for sale	0	0	0
Net (purchases) sales of equity investments trading	0	0	0
Net (purchases) sales of short term investments	(111,814)	(116,461)	73,717
Net (purchases) sales of other investments	0	0	0
Net purchases of investments in other ventures		0	0
Net sales of other assets	0	0	0
Dividends and return of capital from subsidiaries	617,239	1,584,624	1,259,224
Contributions to subsidiaries	(108,674)	(294,733)	(759,456)
Due (from) to subsidiary	23,758	207,996	6,315
Net purchase of Platinum		(904,433)
Net cash (used in) provided by investing activities	398,732	379,634	579,732
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(51,583)	(53,967)	(45,912)
Dividends paid – preference shares	(22,381)	(22,381)	(22,381)
RenaissanceRe common share repurchases	(309,434)	(259,874)	(514,678)
Issuance of debt		0
Net third party redeemable noncontrolling interest share transactions	0	0	0
Net cash used in financing activities	(383,398)	(336,222)	(582,971)
Effect of exchange rate changes on foreign currency cash	0	0	0
Net (decrease) increase in cash and cash equivalents	(3,118)	4,199	(2,810)
Cash and cash equivalents, beginning of period	10,185	5,986	8,796
Cash and cash equivalents, end of period	7,067	10,185	5,986
Reportable Legal Entities | RenRe North America Holdings Inc. (Subsidiary Issuer)
Cash flows provided by (used in) operating activities:
Net cash provided by operating activities	1,477	(9,201)	(18,114)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	69,941	49,807	20,487
Purchases of fixed maturity investments trading	(123,046)	(59,040)	(14,969)
Proceeds from sales and maturities of fixed maturity investments available for sale	0	0	0
Net (purchases) sales of equity investments trading	(2,389)	33,693	13,761
Net (purchases) sales of short term investments	67,684	(63,305)	225
Net (purchases) sales of other investments	0	0	0
Net purchases of investments in other ventures		0	0
Net sales of other assets	0	0	0
Dividends and return of capital from subsidiaries	2,900	180,000	11,204
Contributions to subsidiaries	0	(8,550)	(1,949)
Due (from) to subsidiary	(22,313)	(118,529)	(13,639)
Net purchase of Platinum		0
Net cash (used in) provided by investing activities	(7,223)	14,076	15,120
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	0	0	0
Dividends paid – preference shares	0	0	0
RenaissanceRe common share repurchases	0	0	0
Issuance of debt		0
Net third party redeemable noncontrolling interest share transactions	0	0	0
Net cash used in financing activities	0	0	0
Effect of exchange rate changes on foreign currency cash	0	0	0
Net (decrease) increase in cash and cash equivalents	(5,746)	4,875	(2,994)
Cash and cash equivalents, beginning of period	5,908	1,033	4,027
Cash and cash equivalents, end of period	162	5,908	1,033
Reportable Legal Entities | Platinum Underwriters Finance, Inc. (Subsidiary Issuer)
Cash flows provided by (used in) operating activities:
Net cash provided by operating activities	(14,501)	(6,830)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	145,082	45,087
Purchases of fixed maturity investments trading	(291,053)	0
Proceeds from sales and maturities of fixed maturity investments available for sale	0	0
Net (purchases) sales of equity investments trading	193,022	(269,244)
Net (purchases) sales of short term investments	(32,901)	238,177
Net (purchases) sales of other investments	0	0
Net purchases of investments in other ventures		0
Net sales of other assets	0	0
Dividends and return of capital from subsidiaries	0	65,000
Contributions to subsidiaries	0	(66,753)
Due (from) to subsidiary	(81)	129
Net purchase of Platinum		1,537
Net cash (used in) provided by investing activities	14,069	13,933
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	0	0
Dividends paid – preference shares	0	0
RenaissanceRe common share repurchases	0	0
Issuance of debt		0
Net third party redeemable noncontrolling interest share transactions	0	0
Net cash used in financing activities	0	0
Effect of exchange rate changes on foreign currency cash	0	0
Net (decrease) increase in cash and cash equivalents	(432)	7,103
Cash and cash equivalents, beginning of period	7,103	0
Cash and cash equivalents, end of period	6,671	7,103	0
Reportable Legal Entities | RenaissanceRe Finance, Inc. (Subsidiary Issuer)
Cash flows provided by (used in) operating activities:
Net cash provided by operating activities	(34,607)	(17,871)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	0	0
Purchases of fixed maturity investments trading	0	0
Proceeds from sales and maturities of fixed maturity investments available for sale	0	0
Net (purchases) sales of equity investments trading	0	0
Net (purchases) sales of short term investments	0	0
Net (purchases) sales of other investments	0	0
Net purchases of investments in other ventures		0
Net sales of other assets	0	0
Dividends and return of capital from subsidiaries	13,125	87,553
Contributions to subsidiaries	0	(185,000)
Due (from) to subsidiary	30,202	(183,405)
Net purchase of Platinum		0
Net cash (used in) provided by investing activities	43,327	(280,852)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	0	0
Dividends paid – preference shares	0	0
RenaissanceRe common share repurchases	0	0
Issuance of debt		299,400
Net third party redeemable noncontrolling interest share transactions	0	0
Net cash used in financing activities	0	299,400
Effect of exchange rate changes on foreign currency cash	0	0
Net (decrease) increase in cash and cash equivalents	8,720	677
Cash and cash equivalents, beginning of period	677	0
Cash and cash equivalents, end of period	9,397	677	0
Reportable Legal Entities | Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Cash flows provided by (used in) operating activities:
Net cash provided by operating activities	535,912	487,852	678,342
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	7,572,923	9,323,024	7,573,813
Purchases of fixed maturity investments trading	(7,532,276)	(9,462,845)	(7,535,868)
Proceeds from sales and maturities of fixed maturity investments available for sale	17,692	8,688	7,088
Net (purchases) sales of equity investments trading	(5,845)	87,993	(33,764)
Net (purchases) sales of short term investments	(41,586)	610,705	(28,919)
Net (purchases) sales of other investments	(68,589)	15,843	59,120
Net purchases of investments in other ventures		(10,150)	1,030
Net sales of other assets	400	4,500	6,000
Dividends and return of capital from subsidiaries	(633,264)	(1,917,177)	(1,270,428)
Contributions to subsidiaries	108,674	555,036	761,405
Due (from) to subsidiary	(31,566)	93,809	7,324
Net purchase of Platinum		224,744
Net cash (used in) provided by investing activities	(613,437)	(465,830)	(453,199)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	0	0	0
Dividends paid – preference shares	0	0	0
RenaissanceRe common share repurchases	0	0	0
Issuance of debt		146,189
Net third party redeemable noncontrolling interest share transactions	(2,990)	(193,032)	(111,707)
Net cash used in financing activities	(2,990)	(46,843)	(111,707)
Effect of exchange rate changes on foreign currency cash	(4,637)	(10,732)	9,920
Net (decrease) increase in cash and cash equivalents	(85,152)	(35,553)	123,356
Cash and cash equivalents, beginning of period	483,012	518,565	395,209
Cash and cash equivalents, end of period	$ 397,860	$ 483,012	$ 518,565