Condensed Consolidating Financial Information Provided in Connection with Outstanding Debt of Subsidiaries (Condensed Consolidating Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues
Net premiums earned	$ 913,098	$ 550,028
Net investment income	99,473	82,094
Net foreign exchange losses	(5,728)	(2,846)
Equity in earnings of other ventures	4,564	4,661
Other (loss) income	(4,436)	3,171
Net realized and unrealized (losses) gains on investments	(110,707)	170,013
Total revenues	896,264	807,121
Expenses
Net claims and claim expenses incurred	570,954	227,035
Acquisition expenses	210,604	123,951
Operational expenses	67,461	44,933
Corporate expenses	15,991	38,789
Interest expense	14,927	11,754
Total expenses	879,937	446,462
(Loss) income before equity in net (loss) income of subsidiaries and taxes	16,327	360,659
Equity in net (loss) income of subsidiaries	0	0
Income before taxes	16,327	360,659
Income tax (expense) benefit	8,846	(7,531)
Net (loss) income	25,173	353,128
Net income attributable to redeemable noncontrolling interests	(98,091)	(70,222)
Net (loss) income attributable to RenaissanceRe	(72,918)	282,906
Dividends on preference shares	(9,056)	(9,189)
Net (loss) income (attributable) available to RenaissanceRe common shareholders	(81,974)	273,717
Reportable Legal Entities | RenaissanceRe Finance Inc. (Subsidiary Issuer)
Revenues
Net premiums earned	0	0
Net investment income	883	2,060
Net foreign exchange losses	0	0
Equity in earnings of other ventures	389	965
Other (loss) income	0	0
Net realized and unrealized (losses) gains on investments	116	109
Total revenues	1,388	3,134
Expenses
Net claims and claim expenses incurred	0	0
Acquisition expenses	0	0
Operational expenses	17,318	12,333
Corporate expenses	0	0
Interest expense	9,969	9,252
Total expenses	27,287	21,585
(Loss) income before equity in net (loss) income of subsidiaries and taxes	(25,899)	(18,451)
Equity in net (loss) income of subsidiaries	(33,669)	33,532
Income before taxes	(59,568)	15,081
Income tax (expense) benefit	2,186	1,662
Net (loss) income	(57,382)	16,743
Net income attributable to redeemable noncontrolling interests	0	0
Net (loss) income attributable to RenaissanceRe	(57,382)	16,743
Dividends on preference shares	0	0
Net (loss) income (attributable) available to RenaissanceRe common shareholders	(57,382)	16,743
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Revenues
Net premiums earned	0	0
Net investment income	10,488	8,277
Net foreign exchange losses	(7,330)	(1)
Equity in earnings of other ventures	0	0
Other (loss) income	372	0
Net realized and unrealized (losses) gains on investments	(21,118)	1,002
Total revenues	(17,588)	9,278
Expenses
Net claims and claim expenses incurred	0	0
Acquisition expenses	0	0
Operational expenses	2,732	469
Corporate expenses	8,679	38,828
Interest expense	3,828	1,883
Total expenses	15,239	41,180
(Loss) income before equity in net (loss) income of subsidiaries and taxes	(32,827)	(31,902)
Equity in net (loss) income of subsidiaries	(39,673)	314,887
Income before taxes	(72,500)	282,985
Income tax (expense) benefit	(418)	(79)
Net (loss) income	(72,918)	282,906
Net income attributable to redeemable noncontrolling interests	0	0
Net (loss) income attributable to RenaissanceRe	(72,918)	282,906
Dividends on preference shares	(9,056)	(9,189)
Net (loss) income (attributable) available to RenaissanceRe common shareholders	(81,974)	273,717
Reportable Legal Entities | Other RenaissanceRe Holdings Ltd. Subsidiaries and Eliminations (Non-Guarantor Subsidiaries)
Revenues
Net premiums earned	913,098	550,028
Net investment income	98,542	80,559
Net foreign exchange losses	1,602	(2,845)
Equity in earnings of other ventures	4,175	3,696
Other (loss) income	11,073	3,171
Net realized and unrealized (losses) gains on investments	(89,705)	168,902
Total revenues	938,785	803,511
Expenses
Net claims and claim expenses incurred	570,954	227,035
Acquisition expenses	210,604	123,951
Operational expenses	62,919	42,620
Corporate expenses	7,312	(1,922)
Interest expense	11,517	619
Total expenses	863,306	392,303
(Loss) income before equity in net (loss) income of subsidiaries and taxes	75,479	411,208
Equity in net (loss) income of subsidiaries	16,639	828
Income before taxes	92,118	412,036
Income tax (expense) benefit	7,078	(9,114)
Net (loss) income	99,196	402,922
Net income attributable to redeemable noncontrolling interests	(98,091)	(70,222)
Net (loss) income attributable to RenaissanceRe	1,105	332,700
Dividends on preference shares	0	0
Net (loss) income (attributable) available to RenaissanceRe common shareholders	1,105	332,700
Consolidating Adjustments
Revenues
Net premiums earned	0	0
Net investment income	(10,440)	(8,802)
Net foreign exchange losses	0	0
Equity in earnings of other ventures	0	0
Other (loss) income	(15,881)	0
Net realized and unrealized (losses) gains on investments	0	0
Total revenues	(26,321)	(8,802)
Expenses
Net claims and claim expenses incurred	0	0
Acquisition expenses	0	0
Operational expenses	(15,508)	(10,489)
Corporate expenses	0	1,883
Interest expense	(10,387)	0
Total expenses	(25,895)	(8,606)
(Loss) income before equity in net (loss) income of subsidiaries and taxes	(426)	(196)
Equity in net (loss) income of subsidiaries	56,703	(349,247)
Income before taxes	56,277	(349,443)
Income tax (expense) benefit	0	0
Net (loss) income	56,277	(349,443)
Net income attributable to redeemable noncontrolling interests	0	0
Net (loss) income attributable to RenaissanceRe	56,277	(349,443)
Dividends on preference shares	0	0
Net (loss) income (attributable) available to RenaissanceRe common shareholders	$ 56,277	$ (349,443)