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, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows (used in) provided by operating activities
Net cash provided by operating activities	$ 1,221,701	$ 1,025,787	$ 484,772
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	11,585,576	9,490,669	8,102,514
Purchases of fixed maturity investments trading	(12,489,972)	(10,093,532)	(8,282,720)
Proceeds from sales and maturities of fixed maturity investments available for sale	0	0	17,692
Net (purchases) sales of equity investments trading	14,156	115,837	184,788
Net sales (purchases) of short term investments	(1,436,389)	364,011	(118,617)
Net purchases of other investments	(199,475)	(19,419)	(68,589)
Net purchases of investments in other ventures	(21,473)	0	0
Return of investment from investment in other ventures	8,464	20,000	0
Net sales of other assets	2,500	0	400
Dividends and return of capital from subsidiaries	0	0	0
Contributions to subsidiaries	0	0	0
Due to (from) subsidiaries	0	0	0
Net cash used in investing activities	(2,536,613)	(122,434)	(164,532)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(52,841)	(51,370)	(51,583)
Dividends paid – preference shares	(30,088)	(22,381)	(22,381)
RenaissanceRe common share repurchases	0	(188,591)	(309,434)
RenaissanceRe common share issuance	250,000	0	0
Issuance of preference shares, net of expenses	241,448	0
Issuance of debt, net of expenses	0	295,866	0
Repayment of debt	0	(250,000)	0
Net third party redeemable noncontrolling interest share transactions	665,683	260,475	(2,990)
Taxes paid on withholding shares	(7,862)	(15,139)	(14,943)
Net cash provided by (used in) financing activities	1,066,340	28,860	(401,331)
Effect of exchange rate changes on foreign currency cash	(5,098)	8,222	(4,637)
Net (decrease) increase in cash and cash equivalents	(253,670)	940,435	(85,728)
Cash and cash equivalents, beginning of period	1,361,592	421,157	506,885
Cash and cash equivalents, end of period	1,107,922	1,361,592	421,157
RenaissanceRe Holdings Ltd. (Parent Guarantor)
Cash flows (used in) provided by operating activities
Net cash provided by operating activities	(9,659)	(4,109)	(3,509)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	384,818	261,601	314,568
Purchases of fixed maturity investments trading	(520,935)	(344,463)	(336,345)
Net sales (purchases) of short term investments	48,600	243,571	(111,814)
Dividends and return of capital from subsidiaries	672,098	478,496	617,239
Net cash used in investing activities	(402,120)	289,179	398,732
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(52,841)	(51,370)	(51,583)
Dividends paid – preference shares	(30,088)	(22,381)	(22,381)
RenaissanceRe common share repurchases	0	(188,591)	(309,434)
RenaissanceRe common share issuance	250,000	0	0
Issuance of preference shares, net of expenses	241,448	0	0
Taxes paid on withholding shares	(7,862)	(15,139)	(14,943)
Net cash provided by (used in) financing activities	400,657	(277,481)	(398,341)
Net (decrease) increase in cash and cash equivalents	(11,122)	7,589	(3,118)
Cash and cash equivalents, beginning of period	14,656	7,067	10,185
Cash and cash equivalents, end of period	3,534	14,656	7,067
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Cash flows (used in) provided by operating activities
Net cash provided by operating activities	(9,659)	(4,109)	(3,509)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	384,818	261,601	314,568
Purchases of fixed maturity investments trading	(520,935)	(344,463)	(336,345)
Proceeds from sales and maturities of fixed maturity investments available for sale			0
Net (purchases) sales of equity investments trading	0	0	0
Net sales (purchases) of short term investments	48,600	243,571	(111,814)
Net purchases of other investments	0	0	0
Net purchases of investments in other ventures	0
Return of investment from investment in other ventures	0	0
Net sales of other assets	0		0
Dividends and return of capital from subsidiaries	672,098	478,496	617,239
Contributions to subsidiaries	(785,785)	(669,672)	(108,674)
Due to (from) subsidiaries	(200,916)	319,646	23,758
Net cash used in investing activities	(402,120)	289,179	398,732
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(52,841)	(51,370)	(51,583)
Dividends paid – preference shares	(30,088)	(22,381)	(22,381)
RenaissanceRe common share repurchases		(188,591)	(309,434)
RenaissanceRe common share issuance	250,000
Issuance of preference shares, net of expenses	241,448
Issuance of debt, net of expenses		0
Repayment of debt		0
Net third party redeemable noncontrolling interest share transactions	0	0	0
Taxes paid on withholding shares	(7,862)	(15,139)	(14,943)
Net cash provided by (used in) financing activities	400,657	(277,481)	(398,341)
Effect of exchange rate changes on foreign currency cash	0	0	0
Net (decrease) increase in cash and cash equivalents	(11,122)	7,589	(3,118)
Cash and cash equivalents, beginning of period	14,656	7,067	10,185
Cash and cash equivalents, end of period	3,534	14,656	7,067
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 operating activities	1,162,400	1,388,311	535,912
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	11,046,968	8,550,179	7,572,923
Purchases of fixed maturity investments trading	(11,840,813)	(9,229,732)	(7,532,276)
Proceeds from sales and maturities of fixed maturity investments available for sale			17,692
Net (purchases) sales of equity investments trading	15,464	32,265	(5,845)
Net sales (purchases) of short term investments	(1,485,040)	79,520	(41,586)
Net purchases of other investments	(199,475)	(19,419)	(68,589)
Net purchases of investments in other ventures	(21,473)
Return of investment from investment in other ventures	8,464	20,000
Net sales of other assets	2,500		400
Dividends and return of capital from subsidiaries	(672,098)	(529,537)	(633,264)
Contributions to subsidiaries	867,632	706,211	108,674
Due to (from) subsidiaries	200,992	(319,027)	(31,566)
Net cash used in investing activities	(2,076,879)	(709,540)	(613,437)
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
RenaissanceRe common share issuance	0
Issuance of preference shares, net of expenses	0
Issuance of debt, net of expenses		0
Repayment of debt		0
Net third party redeemable noncontrolling interest share transactions	665,683	260,475	(2,990)
Taxes paid on withholding shares	0	0	0
Net cash provided by (used in) financing activities	665,683	260,475	(2,990)
Effect of exchange rate changes on foreign currency cash	(5,098)	8,222	(4,637)
Net (decrease) increase in cash and cash equivalents	(253,894)	947,468	(85,152)
Cash and cash equivalents, beginning of period	1,345,328	397,860	483,012
Cash and cash equivalents, end of period	1,091,434	1,345,328	397,860
Reportable Legal Entities | RenRe North America Holdings Inc. (Subsidiary Issuer)
Cash flows (used in) provided by operating activities
Net cash provided by operating activities	6,315	(8,253)	1,477
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	97,272	100,248	69,941
Purchases of fixed maturity investments trading	(72,292)	(99,568)	(123,046)
Proceeds from sales and maturities of fixed maturity investments available for sale			0
Net (purchases) sales of equity investments trading	(1,308)	(1,752)	(2,389)
Net sales (purchases) of short term investments	(404)	114	67,684
Net purchases of other investments	0	0	0
Net purchases of investments in other ventures	0
Return of investment from investment in other ventures	0	0
Net sales of other assets	0		0
Dividends and return of capital from subsidiaries	0	9,175	2,900
Contributions to subsidiaries	(16,847)	0	0
Due to (from) subsidiaries	(9,525)	13	(22,313)
Net cash used in investing activities	(3,104)	8,230	(7,223)
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
RenaissanceRe common share issuance	0
Issuance of preference shares, net of expenses	0
Issuance of debt, net of expenses		0
Repayment of debt		0
Net third party redeemable noncontrolling interest share transactions	0	0	0
Taxes paid on withholding shares	0	0	0
Net cash provided by (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	3,211	(23)	(5,746)
Cash and cash equivalents, beginning of period	139	162	5,908
Cash and cash equivalents, end of period	3,350	139	162
Reportable Legal Entities | Platinum Underwriters Finance, Inc. (Subsidiary Issuer)
Cash flows (used in) provided by operating activities
Net cash provided by operating activities		(2,272)	(14,501)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading		289,741	145,082
Purchases of fixed maturity investments trading		(143,991)	(291,053)
Proceeds from sales and maturities of fixed maturity investments available for sale			0
Net (purchases) sales of equity investments trading		85,324	193,022
Net sales (purchases) of short term investments		41,299	(32,901)
Net purchases of other investments		0	0
Return of investment from investment in other ventures		0
Net sales of other assets			0
Dividends and return of capital from subsidiaries		0	0
Contributions to subsidiaries		(26,649)	0
Due to (from) subsidiaries		(123)	(81)
Net cash used in investing activities		245,601	14,069
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, net of expenses		0
Repayment of debt		(250,000)
Net third party redeemable noncontrolling interest share transactions		0	0
Taxes paid on withholding shares		0	0
Net cash provided by (used in) financing activities		(250,000)	0
Effect of exchange rate changes on foreign currency cash		0	0
Net (decrease) increase in cash and cash equivalents		(6,671)	(432)
Cash and cash equivalents, beginning of period	0	6,671	7,103
Cash and cash equivalents, end of period		0	6,671
Reportable Legal Entities | RenaissanceRe Finance, Inc. (Subsidiary Issuer)
Cash flows (used in) provided by operating activities
Net cash provided by operating activities	62,645	(347,890)	(34,607)
Cash flows provided by (used in) investing activities
Proceeds from sales and maturities of fixed maturity investments trading	56,518	288,900	0
Purchases of fixed maturity investments trading	(55,932)	(275,778)	0
Proceeds from sales and maturities of fixed maturity investments available for sale			0
Net (purchases) sales of equity investments trading	0	0	0
Net sales (purchases) of short term investments	455	(493)	0
Net purchases of other investments	0	0	0
Net purchases of investments in other ventures	0
Return of investment from investment in other ventures	0	0
Net sales of other assets	0		0
Dividends and return of capital from subsidiaries	0	41,866	13,125
Contributions to subsidiaries	(65,000)	(9,890)	0
Due to (from) subsidiaries	9,449	(509)	30,202
Net cash used in investing activities	(54,510)	44,096	43,327
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
RenaissanceRe common share issuance	0
Issuance of preference shares, net of expenses	0
Issuance of debt, net of expenses		295,866
Repayment of debt		0
Net third party redeemable noncontrolling interest share transactions	0	0	0
Taxes paid on withholding shares	0	0	0
Net cash provided by (used in) financing activities	0	295,866	0
Effect of exchange rate changes on foreign currency cash	0	0	0
Net (decrease) increase in cash and cash equivalents	8,135	(7,928)	8,720
Cash and cash equivalents, beginning of period	1,469	9,397	677
Cash and cash equivalents, end of period	$ 9,604	$ 1,469	$ 9,397