Condensed Consolidating Financial Information Provided in Connection with Outstanding Debt of Subsidiaries (Condensed Consolidating Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Net premiums earned	$ 574,613	$ 531,849	$ 429,385	$ 440,282	$ 421,473	$ 547,792	$ 382,265	$ 366,045	$ 1,976,129	$ 1,717,575	$ 1,403,430
Net investment income	53,338	80,696	71,356	56,476	73,464	40,257	54,163	54,325	261,866	222,209	181,726
Net foreign exchange (losses) gains	(932)	(4,566)	(10,687)	3,757	(490)	(156)	3,109	8,165	(12,428)	10,628	(13,788)
Equity in earnings (losses) of other ventures	4,143	7,648	5,826	857	2,200	1,794	5,543	(1,507)	18,474	8,030	963
Other loss	5,489	497	1,225	(1,242)	2,362	2,996	2,392	1,665	5,969	9,415	14,178
Net realized and unrealized (losses) gains on investments	(88,654)	13,630	(17,901)	(82,144)	(7,716)	42,052	58,113	43,373	(175,069)	135,822	141,328
Total revenues	547,997	629,754	479,204	417,986	491,293	634,735	505,585	472,066	2,074,941	2,103,679	1,727,837
Expenses
Net claims and claim expenses incurred	477,638	410,510	60,167	171,703	304,064	1,221,696	142,587	193,081	1,120,018	1,861,428	530,831
Acquisition expenses	120,465	109,761	105,052	97,711	98,598	76,761	88,251	83,282	432,989	346,892	289,323
Operational expenses	58,859	40,593	37,543	41,272	29,192	42,537	41,766	47,283	178,267	160,778	197,749
Corporate expenses	12,108	6,841	8,301	6,733	4,237	4,413	4,636	5,286	33,983	18,572	37,402
Interest expense	11,765	11,769	11,768	11,767	11,777	11,799	10,091	10,526	47,069	44,193	42,144
Total expenses	680,835	579,474	222,831	329,186	447,868	1,357,206	287,331	339,458	1,812,326	2,431,863	1,097,449
(Loss) income before equity in net income of subsidiaries and taxes									262,615	(328,184)	630,388
Equity in net income of subsidiaries									0	0	0
Income (loss) before taxes	(132,838)	50,280	256,373	88,800	43,425	(722,471)	218,254	132,608	262,615	(328,184)	630,388
Income tax benefit (expense)	8,852	(1,451)	(4,506)	3,407	(41,226)	18,977	(3,904)	(334)	6,302	(26,487)	(340)
Net income (loss)	(123,986)	48,829	251,867	92,207	2,199	(703,494)	214,350	132,274	268,917	(354,671)	630,048
Net (income) loss attributable to redeemable noncontrolling interests	49,269	(6,440)	(54,483)	(29,899)	(56)	204,277	(37,612)	(34,327)	(41,553)	132,282	(127,086)
Net income (loss) attributable to RenaissanceRe	(74,717)	42,389	197,384	62,308	2,143	(499,217)	176,738	97,947	227,364	(222,389)	502,962
Dividends on preference shares	(9,189)	(9,708)	(5,596)	(5,595)	(5,595)	(5,595)	(5,596)	(5,595)	(30,088)	(22,381)	(22,381)
Net income (loss) available (attributable) to RenaissanceRe common shareholders	$ (83,906)	$ 32,681	$ 191,788	$ 56,713	$ (3,452)	$ (504,812)	$ 171,142	$ 92,352	197,276	(244,770)	480,581
RenaissanceRe Holdings Ltd. (Parent Guarantor)
Revenues
Net investment income									24,791	23,109	24,178
Net foreign exchange (losses) gains									(3)	(1)	(2)
Other loss									0	0	(772)
Net realized and unrealized (losses) gains on investments									633	(1,357)	4,151
Total revenues									25,421	21,751	27,555
Expenses
Operational expenses									7,679	11,314	13,716
Corporate expenses									25,190	18,546	26,848
Interest expense									5,683	1,572	562
Total expenses									38,552	31,432	41,126
(Loss) income before equity in net income of subsidiaries and taxes									(13,131)	(9,681)	(13,571)
Equity in net income of subsidiaries									240,495	(212,708)	516,533
Net income (loss) attributable to RenaissanceRe									227,364	(222,389)	502,962
Dividends on preference shares									(30,088)	(22,381)	(22,381)
Net income (loss) available (attributable) to RenaissanceRe common shareholders									197,276	(244,770)	480,581
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Revenues
Net premiums earned									0	0	0
Net investment income									24,791	23,109	24,178
Net foreign exchange (losses) gains									(3)	(1)	(2)
Equity in earnings (losses) of other ventures									0	0	0
Other loss									0	0	(772)
Net realized and unrealized (losses) gains on investments									633	(1,357)	4,151
Total revenues									25,421	21,751	27,555
Expenses
Net claims and claim expenses incurred									0	0	0
Acquisition expenses									0	0	0
Operational expenses									7,679	11,314	13,716
Corporate expenses									25,190	18,546	26,848
Interest expense									5,683	1,572	562
Total expenses									38,552	31,432	41,126
(Loss) income before equity in net income of subsidiaries and taxes									(13,131)	(9,681)	(13,571)
Equity in net income of subsidiaries									240,495	(212,708)	516,533
Income (loss) before taxes									227,364	(222,389)	502,962
Income tax benefit (expense)									0	0	0
Net income (loss)									227,364	(222,389)	502,962
Net (income) loss attributable to redeemable noncontrolling interests									0	0	0
Net income (loss) attributable to RenaissanceRe									227,364	(222,389)	502,962
Dividends on preference shares									(30,088)	(22,381)	(22,381)
Net income (loss) available (attributable) to RenaissanceRe common shareholders									197,276	(244,770)	480,581
Reportable Legal Entities | Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Revenues
Net premiums earned									1,976,129	1,717,575	1,403,430
Net investment income									261,192	219,490	175,407
Net foreign exchange (losses) gains									(12,425)	10,629	(13,786)
Equity in earnings (losses) of other ventures									15,409	8,253	963
Other loss									5,969	9,415	14,950
Net realized and unrealized (losses) gains on investments									(171,013)	123,121	124,279
Total revenues									2,075,261	2,088,483	1,705,243
Expenses
Net claims and claim expenses incurred									1,120,018	1,861,428	530,831
Acquisition expenses									432,989	346,892	289,323
Operational expenses									164,605	141,572	176,041
Corporate expenses									3,103	26	10,344
Interest expense									4,367	10,075	10,062
Total expenses									1,725,082	2,359,993	1,016,601
(Loss) income before equity in net income of subsidiaries and taxes									350,179	(271,510)	688,642
Equity in net income of subsidiaries									0	0	0
Income (loss) before taxes									350,179	(271,510)	688,642
Income tax benefit (expense)									(399)	(14,328)	(7,617)
Net income (loss)									349,780	(285,838)	681,025
Net (income) loss attributable to redeemable noncontrolling interests									(41,553)	132,282	(127,086)
Net income (loss) attributable to RenaissanceRe									308,227	(153,556)	553,939
Dividends on preference shares									0	0	0
Net income (loss) available (attributable) to RenaissanceRe common shareholders									308,227	(153,556)	553,939
Reportable Legal Entities | RenRe North America Holdings Inc. (Subsidiary Issuer)
Revenues
Net premiums earned									0	0	0
Net investment income									2,193	1,947	1,852
Net foreign exchange (losses) gains									0	0	0
Equity in earnings (losses) of other ventures									0	0	0
Other loss									0	0	0
Net realized and unrealized (losses) gains on investments									(4,360)	9,621	4,659
Total revenues									(2,167)	11,568	6,511
Expenses
Net claims and claim expenses incurred									0	0	0
Acquisition expenses									0	0	0
Operational expenses									110	103	(112)
Corporate expenses									0	0	203
Interest expense									0	0	0
Total expenses									110	103	91
(Loss) income before equity in net income of subsidiaries and taxes									(2,277)	11,465	6,420
Equity in net income of subsidiaries									5,631	756	3,857
Income (loss) before taxes									3,354	12,221	10,277
Income tax benefit (expense)									582	(18,147)	(2,275)
Net income (loss)									3,936	(5,926)	8,002
Net (income) loss attributable to redeemable noncontrolling interests									0	0	0
Net income (loss) attributable to RenaissanceRe									3,936	(5,926)	8,002
Dividends on preference shares									0	0	0
Net income (loss) available (attributable) to RenaissanceRe common shareholders									3,936	(5,926)	8,002
Reportable Legal Entities | Platinum Underwriters Finance, Inc. (Subsidiary Issuer)
Revenues
Net premiums earned										0	0
Net investment income										1,373	3,989
Net foreign exchange (losses) gains										0	0
Equity in earnings (losses) of other ventures										0	0
Other loss										0	0
Net realized and unrealized (losses) gains on investments										4,916	8,193
Total revenues										6,289	12,182
Expenses
Net claims and claim expenses incurred										0	0
Acquisition expenses										0	0
Operational expenses										85	296
Corporate expenses										0	0
Interest expense										2,461	5,906
Total expenses										2,546	6,202
(Loss) income before equity in net income of subsidiaries and taxes										3,743	5,980
Equity in net income of subsidiaries										28,028	25,073
Income (loss) before taxes										31,771	31,053
Income tax benefit (expense)										(1,175)	(1,462)
Net income (loss)										30,596	29,591
Net (income) loss attributable to redeemable noncontrolling interests										0	0
Net income (loss) attributable to RenaissanceRe										30,596	29,591
Dividends on preference shares										0	0
Net income (loss) available (attributable) to RenaissanceRe common shareholders										30,596	29,591
Reportable Legal Entities | RenaissanceRe Finance, Inc. (Subsidiary Issuer)
Revenues
Net premiums earned									0	0	0
Net investment income									6,219	3,090	569
Net foreign exchange (losses) gains									0	0	0
Equity in earnings (losses) of other ventures									3,065	(223)	0
Other loss									0	0	0
Net realized and unrealized (losses) gains on investments									(329)	(479)	46
Total revenues									8,955	2,388	615
Expenses
Net claims and claim expenses incurred									0	0	0
Acquisition expenses									0	0	0
Operational expenses									34,534	26,063	22,152
Corporate expenses									7	0	7
Interest expense									37,019	31,657	26,176
Total expenses									71,560	57,720	48,335
(Loss) income before equity in net income of subsidiaries and taxes									(62,605)	(55,332)	(47,720)
Equity in net income of subsidiaries									9,091	9,298	38,628
Income (loss) before taxes									(53,514)	(46,034)	(9,092)
Income tax benefit (expense)									6,119	7,163	11,014
Net income (loss)									(47,395)	(38,871)	1,922
Net (income) loss attributable to redeemable noncontrolling interests									0	0	0
Net income (loss) attributable to RenaissanceRe									(47,395)	(38,871)	1,922
Dividends on preference shares									0	0	0
Net income (loss) available (attributable) to RenaissanceRe common shareholders									(47,395)	(38,871)	1,922
Consolidating Adjustments
Revenues
Net premiums earned									0	0	0
Net investment income									(32,529)	(26,800)	(24,269)
Net foreign exchange (losses) gains									0	0	0
Equity in earnings (losses) of other ventures									0	0	0
Other loss									0	0	0
Net realized and unrealized (losses) gains on investments									0	0	0
Total revenues									(32,529)	(26,800)	(24,269)
Expenses
Net claims and claim expenses incurred									0	0	0
Acquisition expenses									0	0	0
Operational expenses									(28,661)	(18,359)	(14,344)
Corporate expenses									5,683	0	0
Interest expense									0	(1,572)	(562)
Total expenses									(22,978)	(19,931)	(14,906)
(Loss) income before equity in net income of subsidiaries and taxes									(9,551)	(6,869)	(9,363)
Equity in net income of subsidiaries									(255,217)	174,626	(584,091)
Income (loss) before taxes									(264,768)	167,757	(593,454)
Income tax benefit (expense)									0	0	0
Net income (loss)									(264,768)	167,757	(593,454)
Net (income) loss attributable to redeemable noncontrolling interests									0	0	0
Net income (loss) attributable to RenaissanceRe									(264,768)	167,757	(593,454)
Dividends on preference shares									0	0	0
Net income (loss) available (attributable) to RenaissanceRe common shareholders									$ (264,768)	$ 167,757	$ (593,454)