Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement Of Cash Flows) (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Cash flows (used in) provided by operating activities
Net cash provided by (used in) operating activities	$ 117,172	$ (29,370)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	4,780,406	4,761,975
Purchases of fixed maturity investments trading	(4,984,820)	(4,596,118)
Proceeds from sales and maturities of fixed maturity investments available for sale	5,216	5,000
Net sales (purchases) of equity investments trading	181,634	(166,485)
Net sales of short term investments	245,899	360,162
Net purchases of other investments	(52,778)	(1,250)
Net purchases of investments in other ventures	0	(45)
Net sales of other assets	0	4,500
Dividends and return of capital from subsidiaries	0	0
Contributions to subsidiaries	0	0
Due (from) to subsidiary	0	0
Net purchase of Platinum	0	(678,152)
Net cash provided by (used in) investing activities	175,557	(310,413)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(26,198)	(27,479)
Dividends paid – preference shares	(11,191)	(11,191)
RenaissanceRe common share repurchases	(265,003)	(736)
Net issuance of debt	0	445,589
Net third party redeemable noncontrolling interest share transactions	(43,909)	(187,064)
Net cash (used in) provided by financing activities	(346,301)	219,119
Effect of exchange rate changes on foreign currency cash	2,208	(6,830)
Net decrease in cash and cash equivalents	(51,364)	(127,494)
Cash and cash equivalents, beginning of period	506,885	525,584	$ 525,584
Cash and cash equivalents, end of period	455,521	398,090	506,885
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Cash flows (used in) provided by operating activities
Net cash provided by (used in) operating activities	(11,131)	59,434
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	210,933	14,718
Purchases of fixed maturity investments trading	(324,462)	(56,559)
Proceeds from sales and maturities of fixed maturity investments available for sale	0	0
Net sales (purchases) of equity investments trading	0	0
Net sales of short term investments	195,915	(1,088)
Net purchases of other investments	0	0
Net purchases of investments in other ventures		0
Net sales of other assets		0
Dividends and return of capital from subsidiaries	341,011	1,050,762
Contributions to subsidiaries	(95,001)	(231,964)
Due (from) to subsidiary	(22,676)	114,266
Net purchase of Platinum		(904,433)
Net cash provided by (used in) investing activities	305,720	(14,298)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(26,198)	(27,479)
Dividends paid – preference shares	(11,191)	(11,191)
RenaissanceRe common share repurchases	(265,003)	(736)
Net issuance of debt		0
Net third party redeemable noncontrolling interest share transactions	0	0
Net cash (used in) provided by financing activities	(302,392)	(39,406)
Effect of exchange rate changes on foreign currency cash	0	0
Net decrease in cash and cash equivalents	(7,803)	5,730
Cash and cash equivalents, beginning of period	10,185	5,986	5,986
Cash and cash equivalents, end of period	2,382	11,716	10,185
Reportable Legal Entities | RenRe North America Holdings Inc. (Subsidiary Issuer)
Cash flows (used in) provided by operating activities
Net cash provided by (used in) operating activities	297	(5,411)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	50,890	7,016
Purchases of fixed maturity investments trading	(105,772)	(38,668)
Proceeds from sales and maturities of fixed maturity investments available for sale	0	0
Net sales (purchases) of equity investments trading	(2,195)	33,687
Net sales of short term investments	62,403	(5,848)
Net purchases of other investments	0	0
Net purchases of investments in other ventures		0
Net sales of other assets		0
Dividends and return of capital from subsidiaries	2,900	193,850
Contributions to subsidiaries	0	0
Due (from) to subsidiary	(14,396)	(183,513)
Net purchase of Platinum		0
Net cash provided by (used in) investing activities	(6,170)	6,524
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
Net issuance of debt		0
Net third party redeemable noncontrolling interest share transactions	0	0
Net cash (used in) provided by financing activities	0	0
Effect of exchange rate changes on foreign currency cash	0	0
Net decrease in cash and cash equivalents	(5,873)	1,113
Cash and cash equivalents, beginning of period	5,908	1,033	1,033
Cash and cash equivalents, end of period	35	2,146	5,908
Reportable Legal Entities | Platinum Underwriters Finance, Inc. (Subsidiary Issuer)
Cash flows (used in) provided by operating activities
Net cash provided by (used in) operating activities	(3,914)	(10,030)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	67,839	45,087
Purchases of fixed maturity investments trading	(203,883)	0
Proceeds from sales and maturities of fixed maturity investments available for sale	0	0
Net sales (purchases) of equity investments trading	193,207	(273,501)
Net sales of short term investments	(58,367)	238,048
Net purchases of other investments	0	0
Net purchases of investments in other ventures		0
Net sales of other assets		0
Dividends and return of capital from subsidiaries	0	0
Contributions to subsidiaries	0	0
Due (from) to subsidiary	(92)	(52)
Net purchase of Platinum		1,537
Net cash provided by (used in) investing activities	(1,296)	11,119
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
Net issuance of debt		0
Net third party redeemable noncontrolling interest share transactions	0	0
Net cash (used in) provided by financing activities	0	0
Effect of exchange rate changes on foreign currency cash	0	0
Net decrease in cash and cash equivalents	(5,210)	1,089
Cash and cash equivalents, beginning of period	7,103	0	0
Cash and cash equivalents, end of period	1,893	1,089	7,103
Reportable Legal Entities | RenaissanceRe Finance, Inc. (Subsidiary Issuer)
Cash flows (used in) provided by operating activities
Net cash provided by (used in) operating activities	(24,197)	(4,337)
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 sales (purchases) of equity investments trading	0	0
Net sales of short term investments	0	0
Net purchases of other investments	0	0
Net purchases of investments in other ventures		0
Net sales of other assets		0
Dividends and return of capital from subsidiaries	0	0
Contributions to subsidiaries	0	(180,000)
Due (from) to subsidiary	24,134	(114,839)
Net purchase of Platinum		0
Net cash provided by (used in) investing activities	24,134	(294,839)
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
Net issuance of debt		299,400
Net third party redeemable noncontrolling interest share transactions	0	0
Net cash (used in) provided by financing activities	0	299,400
Effect of exchange rate changes on foreign currency cash	0	0
Net decrease in cash and cash equivalents	(63)	224
Cash and cash equivalents, beginning of period	677	0	0
Cash and cash equivalents, end of period	614	224	677
Reportable Legal Entities | Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Cash flows (used in) provided by operating activities
Net cash provided by (used in) operating activities	156,117	(69,026)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	4,450,744	4,695,154
Purchases of fixed maturity investments trading	(4,350,703)	(4,500,891)
Proceeds from sales and maturities of fixed maturity investments available for sale	5,216	5,000
Net sales (purchases) of equity investments trading	(9,378)	73,329
Net sales of short term investments	45,948	129,050
Net purchases of other investments	(52,778)	(1,250)
Net purchases of investments in other ventures		(45)
Net sales of other assets		4,500
Dividends and return of capital from subsidiaries	(343,911)	(1,244,612)
Contributions to subsidiaries	95,001	411,964
Due (from) to subsidiary	13,030	184,138
Net purchase of Platinum		224,744
Net cash provided by (used in) investing activities	(146,831)	(18,919)
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
Net issuance of debt		146,189
Net third party redeemable noncontrolling interest share transactions	(43,909)	(187,064)
Net cash (used in) provided by financing activities	(43,909)	(40,875)
Effect of exchange rate changes on foreign currency cash	2,208	(6,830)
Net decrease in cash and cash equivalents	(32,415)	(135,650)
Cash and cash equivalents, beginning of period	483,012	518,565	518,565
Cash and cash equivalents, end of period	$ 450,597	$ 382,915	$ 483,012