Condensed Consolidating Financial Information Provided in Connection with Outstanding Debt of Subsidiaries (Condensed Consolidating Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues
Net premiums earned	$ 429,385	$ 382,265	$ 869,667	$ 748,310
Net investment income	71,356	54,163	127,832	108,488
Net foreign exchange (losses) gains	(10,687)	3,109	(6,930)	11,274
Equity in earnings of other ventures	5,826	5,543	6,683	4,036
Other income (loss)	1,225	2,392	(17)	4,057
Net realized and unrealized (losses) gains on investments	(17,901)	58,113	(100,045)	101,486
Total revenues	479,204	505,585	897,190	977,651
Expenses
Net claims and claim expenses incurred	60,167	142,587	231,870	335,668
Acquisition expenses	105,052	88,251	202,763	171,533
Operational expenses	37,543	41,766	78,815	89,049
Corporate expenses	8,301	4,636	15,034	9,922
Interest expense	11,768	10,091	23,535	20,617
Total expenses	222,831	287,331	552,017	626,789
(Loss) income before equity in net income (loss) of subsidiaries and taxes	256,373	218,254	345,173	350,862
Equity in net income (loss) of subsidiaries	0	0	0	0
Income before taxes	256,373	218,254	345,173	350,862
Income tax expense	(4,506)	(3,904)	(1,099)	(4,238)
Net income	251,867	214,350	344,074	346,624
Net (income) loss attributable to redeemable noncontrolling interests	(54,483)	(37,612)	(84,382)	(71,939)
Net income attributable to RenaissanceRe	197,384	176,738	259,692	274,685
Dividends on preference shares	(5,596)	(5,596)	(11,191)	(11,191)
Net income available to RenaissanceRe common shareholders	191,788	171,142	248,501	263,494
Reportable Legal Entities | RenRe North America Holdings Inc. (Subsidiary Issuer)
Revenues
Net premiums earned	0	0	0	0
Net investment income	577	466	1,090	892
Net foreign exchange (losses) gains	0	0	0	0
Equity in earnings of other ventures	0	0	0	0
Other income (loss)	0	0	0	0
Net realized and unrealized (losses) gains on investments	1,713	1,421	427	4,342
Total revenues	2,290	1,887	1,517	5,234
Expenses
Net claims and claim expenses incurred	0	0	0	0
Acquisition expenses	0	0	0	0
Operational expenses	21	16	31	40
Corporate expenses	0	0	0	0
Interest expense	0	0	0	0
Total expenses	21	16	31	40
(Loss) income before equity in net income (loss) of subsidiaries and taxes	2,269	1,871	1,486	5,194
Equity in net income (loss) of subsidiaries	716	1,220	1,550	2,306
Income before taxes	2,985	3,091	3,036	7,500
Income tax expense	(468)	(584)	(247)	(1,682)
Net income	2,517	2,507	2,789	5,818
Net (income) loss attributable to redeemable noncontrolling interests	0	0	0	0
Net income attributable to RenaissanceRe	2,517	2,507	2,789	5,818
Dividends on preference shares	0	0	0	0
Net income available to RenaissanceRe common shareholders	2,517	2,507	2,789	5,818
Reportable Legal Entities | Platinum Underwriters Finance, Inc. (Subsidiary Issuer)
Revenues
Net premiums earned		0		0
Net investment income		535		1,376
Net foreign exchange (losses) gains		0		0
Equity in earnings of other ventures		0		0
Other income (loss)		0		0
Net realized and unrealized (losses) gains on investments		191		4,916
Total revenues		726		6,292
Expenses
Net claims and claim expenses incurred		0		0
Acquisition expenses		0		0
Operational expenses		35		85
Corporate expenses		0		0
Interest expense		985		2,461
Total expenses		1,020		2,546
(Loss) income before equity in net income (loss) of subsidiaries and taxes		(294)		3,746
Equity in net income (loss) of subsidiaries		18,185		28,028
Income before taxes		17,891		31,774
Income tax expense		104		(1,204)
Net income		17,995		30,570
Net (income) loss attributable to redeemable noncontrolling interests		0		0
Net income attributable to RenaissanceRe		17,995		30,570
Dividends on preference shares		0		0
Net income available to RenaissanceRe common shareholders		17,995		30,570
Reportable Legal Entities | RenaissanceRe Finance, Inc. (Subsidiary Issuer)
Revenues
Net premiums earned	0	0	0	0
Net investment income	1,206	239	2,440	508
Net foreign exchange (losses) gains	0	0	0	0
Equity in earnings of other ventures	544	302	1,755	(450)
Other income (loss)	0	0	0	0
Net realized and unrealized (losses) gains on investments	(67)	(242)	(326)	(268)
Total revenues	1,683	299	3,869	(210)
Expenses
Net claims and claim expenses incurred	0	0	0	0
Acquisition expenses	0	0	0	0
Operational expenses	8,174	6,647	19,244	14,626
Corporate expenses	7	0	7	0
Interest expense	9,254	6,601	18,506	13,143
Total expenses	17,435	13,248	37,757	27,769
(Loss) income before equity in net income (loss) of subsidiaries and taxes	(15,752)	(12,949)	(33,888)	(27,979)
Equity in net income (loss) of subsidiaries	21,152	20,438	17,339	36,936
Income before taxes	5,400	7,489	(16,549)	8,957
Income tax expense	2,022	2,902	3,837	5,974
Net income	7,422	10,391	(12,712)	14,931
Net (income) loss attributable to redeemable noncontrolling interests	0	0	0	0
Net income attributable to RenaissanceRe	7,422	10,391	(12,712)	14,931
Dividends on preference shares	0	0	0	0
Net income available to RenaissanceRe common shareholders	7,422	10,391	(12,712)	14,931
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Revenues
Net premiums earned	0	0	0	0
Net investment income	5,927	5,284	11,962	10,741
Net foreign exchange (losses) gains	(1)	(1)	(4)	(1)
Equity in earnings of other ventures	0	0	0	0
Other income (loss)	0	0	0	(1)
Net realized and unrealized (losses) gains on investments	16	(8)	(645)	45
Total revenues	5,942	5,275	11,313	10,784
Expenses
Net claims and claim expenses incurred	0	0	0	0
Acquisition expenses	0	0	0	0
Operational expenses	2,668	3,190	3,981	6,488
Corporate expenses	5,036	4,798	8,720	10,006
Interest expense	1,108	141	2,216	281
Total expenses	8,812	8,129	14,917	16,775
(Loss) income before equity in net income (loss) of subsidiaries and taxes	(2,870)	(2,854)	(3,604)	(5,991)
Equity in net income (loss) of subsidiaries	202,525	178,746	264,951	280,099
Income before taxes	199,655	175,892	261,347	274,108
Income tax expense	(2,271)	846	(1,655)	577
Net income	197,384	176,738	259,692	274,685
Net (income) loss attributable to redeemable noncontrolling interests	0	0	0	0
Net income attributable to RenaissanceRe	197,384	176,738	259,692	274,685
Dividends on preference shares	(5,596)	(5,596)	(11,191)	(11,191)
Net income available to RenaissanceRe common shareholders	191,788	171,142	248,501	263,494
Reportable Legal Entities | Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Revenues
Net premiums earned	429,385	382,265	869,667	748,310
Net investment income	71,257	53,891	127,562	107,474
Net foreign exchange (losses) gains	(10,686)	3,110	(6,942)	11,275
Equity in earnings of other ventures	5,282	5,241	4,928	4,486
Other income (loss)	1,225	2,392	(17)	4,058
Net realized and unrealized (losses) gains on investments	(19,563)	56,751	(99,501)	92,451
Total revenues	476,900	503,650	895,697	968,054
Expenses
Net claims and claim expenses incurred	60,167	142,587	231,870	335,668
Acquisition expenses	105,052	88,251	202,763	171,533
Operational expenses	33,106	36,402	71,039	78,460
Corporate expenses	3,258	(162)	6,307	(84)
Interest expense	2,514	2,505	5,029	5,013
Total expenses	204,097	269,583	517,008	590,590
(Loss) income before equity in net income (loss) of subsidiaries and taxes	272,803	234,067	378,689	377,464
Equity in net income (loss) of subsidiaries	0	0	0	0
Income before taxes	272,803	234,067	378,689	377,464
Income tax expense	(3,789)	(7,172)	(3,034)	(7,903)
Net income	269,014	226,895	375,655	369,561
Net (income) loss attributable to redeemable noncontrolling interests	(54,483)	(37,612)	(84,382)	(71,939)
Net income attributable to RenaissanceRe	214,531	189,283	291,273	297,622
Dividends on preference shares	0	0	0	0
Net income available to RenaissanceRe common shareholders	214,531	189,283	291,273	297,622
Consolidating Adjustments
Revenues
Net premiums earned	0	0	0	0
Net investment income	(7,611)	(6,252)	(15,222)	(12,503)
Net foreign exchange (losses) gains	0	0	0	0
Equity in earnings of other ventures	0	0	0	0
Other income (loss)	0	0	0	0
Net realized and unrealized (losses) gains on investments	0	0	0	0
Total revenues	(7,611)	(6,252)	(15,222)	(12,503)
Expenses
Net claims and claim expenses incurred	0	0	0	0
Acquisition expenses	0	0	0	0
Operational expenses	(6,426)	(4,524)	(15,480)	(10,650)
Corporate expenses	0	0	0	0
Interest expense	(1,108)	(141)	(2,216)	(281)
Total expenses	(7,534)	(4,665)	(17,696)	(10,931)
(Loss) income before equity in net income (loss) of subsidiaries and taxes	(77)	(1,587)	2,474	(1,572)
Equity in net income (loss) of subsidiaries	(224,393)	(218,589)	(283,840)	(347,369)
Income before taxes	(224,470)	(220,176)	(281,366)	(348,941)
Income tax expense	0	0	0	0
Net income	(224,470)	(220,176)	(281,366)	(348,941)
Net (income) loss attributable to redeemable noncontrolling interests	0	0	0	0
Net income attributable to RenaissanceRe	(224,470)	(220,176)	(281,366)	(348,941)
Dividends on preference shares	0	0	0	0
Net income available to RenaissanceRe common shareholders	$ (224,470)	$ (220,176)	$ (281,366)	$ (348,941)