Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement Of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues
Net premiums earned	$ 547,792	$ 346,521	$ 1,296,102	$ 1,051,529
Net investment income (loss)	40,257	51,423	148,745	134,410
Net foreign exchange (losses) gains	(156)	(5,986)	11,118	(8,368)
Equity in earnings (losses) of other ventures	1,794	(11,630)	5,830	(3,997)
Other income (loss)	2,996	2,268	7,053	9,001
Net realized and unrealized gains (losses) on investments	42,052	59,870	143,538	191,295
Total revenues	634,735	442,466	1,612,386	1,373,870
Expenses
Net claims and claim expenses incurred	1,221,696	112,575	1,557,364	406,930
Acquisition expenses	76,761	80,580	248,294	215,177
Operational expenses	42,537	40,493	131,586	147,801
Corporate expenses	4,413	11,537	14,335	25,514
Interest expense	11,799	10,536	32,416	31,610
Total expenses	1,357,206	255,721	1,983,995	827,032
(Loss) income before equity in net income (loss) of subsidiaries and taxes	(722,471)	186,745	(371,609)	546,838
Equity in net income (loss) of subsidiaries	0	0	0	0
(Loss) income before taxes	(722,471)	186,745	(371,609)	546,838
Income tax benefit (expense)	18,977	1,316	14,739	(8,040)
Net (loss) income	(703,494)	188,061	(356,870)	538,798
Net loss attributable to redeemable noncontrolling interests	204,277	(35,641)	132,338	(110,867)
Net (loss) income attributable to RenaissanceRe	(499,217)	152,420	(224,532)	427,931
Dividends on preference shares	(5,595)	(5,595)	(16,786)	(16,786)
Net (loss) income (attributable) available to RenaissanceRe common shareholders	(504,812)	146,825	(241,318)	411,145
Reportable Legal Entities | RenRe North America Holdings Inc. (Subsidiary Issuer)
Revenues
Net premiums earned	0	0	0	0
Net investment income (loss)	544	441	1,436	1,395
Net foreign exchange (losses) gains	0	0	0	0
Equity in earnings (losses) of other ventures	0	0	0	0
Other income (loss)	0	0	0	0
Net realized and unrealized gains (losses) on investments	2,186	1,397	6,528	3,651
Total revenues	2,730	1,838	7,964	5,046
Expenses
Net claims and claim expenses incurred	0	0	0	0
Acquisition expenses	0	0	0	0
Operational expenses	17	36	57	(61)
Corporate expenses	0	0	0	203
Interest expense	0	0	0	0
Total expenses	17	36	57	142
(Loss) income before equity in net income (loss) of subsidiaries and taxes	2,713	1,802	7,907	4,904
Equity in net income (loss) of subsidiaries	928	1,463	3,234	2,996
(Loss) income before taxes	3,641	3,265	11,141	7,900
Income tax benefit (expense)	(890)	(324)	(2,572)	(1,791)
Net (loss) income	2,751	2,941	8,569	6,109
Net loss attributable to redeemable noncontrolling interests	0	0	0	0
Net (loss) income attributable to RenaissanceRe	2,751	2,941	8,569	6,109
Dividends on preference shares	0	0	0	0
Net (loss) income (attributable) available to RenaissanceRe common shareholders	2,751	2,941	8,569	6,109
Reportable Legal Entities | Platinum Underwriters Finance, Inc. (Subsidiary Issuer)
Revenues
Net premiums earned	0	0	0	0
Net investment income (loss)	(3)	795	1,373	3,074
Net foreign exchange (losses) gains	0	0	0	0
Equity in earnings (losses) of other ventures	0	0	0	0
Other income (loss)	0	0	0	0
Net realized and unrealized gains (losses) on investments	0	2,105	4,916	7,483
Total revenues	(3)	2,900	6,289	10,557
Expenses
Net claims and claim expenses incurred	0	0	0	0
Acquisition expenses	0	0	0	0
Operational expenses	1	60	86	176
Corporate expenses	0	0	0	0
Interest expense	0	1,476	2,461	4,429
Total expenses	1	1,536	2,547	4,605
(Loss) income before equity in net income (loss) of subsidiaries and taxes	(4)	1,364	3,742	5,952
Equity in net income (loss) of subsidiaries	0	(2,694)	28,028	31,727
(Loss) income before taxes	(4)	(1,330)	31,770	37,679
Income tax benefit (expense)	29	(401)	(1,175)	(1,583)
Net (loss) income	25	(1,731)	30,595	36,096
Net loss attributable to redeemable noncontrolling interests	0	0	0	0
Net (loss) income attributable to RenaissanceRe	25	(1,731)	30,595	36,096
Dividends on preference shares	0	0	0	0
Net (loss) income (attributable) available to RenaissanceRe common shareholders	25	(1,731)	30,595	36,096
Reportable Legal Entities | RenaissanceRe Finance, Inc. (Subsidiary Issuer)
Revenues
Net premiums earned	0	0	0	0
Net investment income (loss)	1,335	140	1,843	421
Net foreign exchange (losses) gains	0	0	0	0
Equity in earnings (losses) of other ventures	38	0	(412)	0
Other income (loss)	0	0	0	0
Net realized and unrealized gains (losses) on investments	51	0	(217)	0
Total revenues	1,424	140	1,214	421
Expenses
Net claims and claim expenses incurred	0	0	0	0
Acquisition expenses	0	0	0	0
Operational expenses	6,266	5,021	20,892	16,603
Corporate expenses	0	0	0	7
Interest expense	9,258	6,545	22,401	19,632
Total expenses	15,524	11,566	43,293	36,242
(Loss) income before equity in net income (loss) of subsidiaries and taxes	(14,100)	(11,426)	(42,079)	(35,821)
Equity in net income (loss) of subsidiaries	(16,352)	1,130	20,584	42,774
(Loss) income before taxes	(30,452)	(10,296)	(21,495)	6,953
Income tax benefit (expense)	3,307	2,785	9,281	8,456
Net (loss) income	(27,145)	(7,511)	(12,214)	15,409
Net loss attributable to redeemable noncontrolling interests	0	0	0	0
Net (loss) income attributable to RenaissanceRe	(27,145)	(7,511)	(12,214)	15,409
Dividends on preference shares	0	0	0	0
Net (loss) income (attributable) available to RenaissanceRe common shareholders	(27,145)	(7,511)	(12,214)	15,409
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Revenues
Net premiums earned	0	0	0	0
Net investment income (loss)	5,725	5,892	16,466	18,499
Net foreign exchange (losses) gains	0	0	(1)	(2)
Equity in earnings (losses) of other ventures	0	0	0	0
Other income (loss)	1	21	0	(770)
Net realized and unrealized gains (losses) on investments	110	(336)	155	4,951
Total revenues	5,836	5,577	16,620	22,678
Expenses
Net claims and claim expenses incurred	0	0	0	0
Acquisition expenses	0	0	0	0
Operational expenses	2,910	(1,233)	9,398	(3,038)
Corporate expenses	4,634	11,617	14,640	22,411
Interest expense	183	140	464	421
Total expenses	7,727	10,524	24,502	19,794
(Loss) income before equity in net income (loss) of subsidiaries and taxes	(1,891)	(4,947)	(7,882)	2,884
Equity in net income (loss) of subsidiaries	(499,408)	158,862	(219,309)	424,077
(Loss) income before taxes	(501,299)	153,915	(227,191)	426,961
Income tax benefit (expense)	2,082	(1,495)	2,659	970
Net (loss) income	(499,217)	152,420	(224,532)	427,931
Net loss attributable to redeemable noncontrolling interests	0	0	0	0
Net (loss) income attributable to RenaissanceRe	(499,217)	152,420	(224,532)	427,931
Dividends on preference shares	(5,595)	(5,595)	(16,786)	(16,786)
Net (loss) income (attributable) available to RenaissanceRe common shareholders	(504,812)	146,825	(241,318)	411,145
Reportable Legal Entities | Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Revenues
Net premiums earned	547,792	346,521	1,296,102	1,051,529
Net investment income (loss)	39,342	50,406	146,816	129,038
Net foreign exchange (losses) gains	(156)	(5,986)	11,119	(8,366)
Equity in earnings (losses) of other ventures	1,756	(11,630)	6,242	(3,997)
Other income (loss)	2,995	2,247	7,053	9,771
Net realized and unrealized gains (losses) on investments	39,705	56,704	132,156	175,210
Total revenues	631,434	438,262	1,599,488	1,353,185
Expenses
Net claims and claim expenses incurred	1,221,696	112,575	1,557,364	406,930
Acquisition expenses	76,761	80,580	248,294	215,177
Operational expenses	37,752	40,018	116,212	145,466
Corporate expenses	(221)	(80)	(305)	2,893
Interest expense	2,541	2,515	7,554	7,549
Total expenses	1,338,529	235,608	1,929,119	778,015
(Loss) income before equity in net income (loss) of subsidiaries and taxes	(707,095)	202,654	(329,631)	575,170
Equity in net income (loss) of subsidiaries	0	0	0	0
(Loss) income before taxes	(707,095)	202,654	(329,631)	575,170
Income tax benefit (expense)	14,449	751	6,546	(14,092)
Net (loss) income	(692,646)	203,405	(323,085)	561,078
Net loss attributable to redeemable noncontrolling interests	204,277	(35,641)	132,338	(110,867)
Net (loss) income attributable to RenaissanceRe	(488,369)	167,764	(190,747)	450,211
Dividends on preference shares	0	0	0	0
Net (loss) income (attributable) available to RenaissanceRe common shareholders	(488,369)	167,764	(190,747)	450,211
Consolidating Adjustments
Revenues
Net premiums earned	0	0	0	0
Net investment income (loss)	(6,686)	(6,251)	(19,189)	(18,017)
Net foreign exchange (losses) gains	0	0	0	0
Equity in earnings (losses) of other ventures	0	0	0	0
Other income (loss)	0	0	0	0
Net realized and unrealized gains (losses) on investments	0	0	0	0
Total revenues	(6,686)	(6,251)	(19,189)	(18,017)
Expenses
Net claims and claim expenses incurred	0	0	0	0
Acquisition expenses	0	0	0	0
Operational expenses	(4,409)	(3,409)	(15,059)	(11,345)
Corporate expenses	0	0	0	0
Interest expense	(183)	(140)	(464)	(421)
Total expenses	(4,592)	(3,549)	(15,523)	(11,766)
(Loss) income before equity in net income (loss) of subsidiaries and taxes	(2,094)	(2,702)	(3,666)	(6,251)
Equity in net income (loss) of subsidiaries	514,832	(158,761)	167,463	(501,574)
(Loss) income before taxes	512,738	(161,463)	163,797	(507,825)
Income tax benefit (expense)	0	0	0	0
Net (loss) income	512,738	(161,463)	163,797	(507,825)
Net loss attributable to redeemable noncontrolling interests	0	0	0	0
Net (loss) income attributable to RenaissanceRe	512,738	(161,463)	163,797	(507,825)
Dividends on preference shares	0	0	0	0
Net (loss) income (attributable) available to RenaissanceRe common shareholders	$ 512,738	$ (161,463)	$ 163,797	$ (507,825)