Condensed Consolidating Financial Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net income	$ 92,207	$ 132,274
Change in net unrealized gains on investments	(30)	(1,491)
Comprehensive income	92,177	130,783
Net income attributable to redeemable noncontrolling interests	(29,899)	(34,327)
Comprehensive loss attributable to redeemable noncontrolling interests	(29,899)	(34,327)
Comprehensive income attributable to RenaissanceRe	62,278	96,456
Reportable Legal Entities | RenRe North America Holdings Inc. (Subsidiary Issuer)
Condensed Financial Statements, Captions [Line Items]
Net income	272	3,311
Change in net unrealized gains on investments	0	0
Comprehensive income	272	3,311
Net income attributable to redeemable noncontrolling interests	0	0
Comprehensive loss attributable to redeemable noncontrolling interests	0	0
Comprehensive income attributable to RenaissanceRe	272	3,311
Reportable Legal Entities | Platinum Underwriters Finance, Inc. (Subsidiary Issuer)
Condensed Financial Statements, Captions [Line Items]
Net income		12,575
Change in net unrealized gains on investments		0
Comprehensive income		12,575
Net income attributable to redeemable noncontrolling interests		0
Comprehensive loss attributable to redeemable noncontrolling interests		0
Comprehensive income attributable to RenaissanceRe		12,575
Reportable Legal Entities | RenaissanceRe Finance, Inc. (Subsidiary Issuer)
Condensed Financial Statements, Captions [Line Items]
Net income	(20,134)	4,540
Change in net unrealized gains on investments	0	0
Comprehensive income	(20,134)	4,540
Net income attributable to redeemable noncontrolling interests	0	0
Comprehensive loss attributable to redeemable noncontrolling interests	0	0
Comprehensive income attributable to RenaissanceRe	(20,134)	4,540
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Condensed Financial Statements, Captions [Line Items]
Net income	62,308	97,947
Change in net unrealized gains on investments	0	0
Comprehensive income	62,308	97,947
Net income attributable to redeemable noncontrolling interests	0	0
Comprehensive loss attributable to redeemable noncontrolling interests	0	0
Comprehensive income attributable to RenaissanceRe	62,308	97,947
Reportable Legal Entities | Other RenaissanceRe Holdings Ltd. Subsidiaries And Eliminations (Non-Guarantor Subsidiaries)
Condensed Financial Statements, Captions [Line Items]
Net income	106,657	142,666
Change in net unrealized gains on investments	(30)	(1,491)
Comprehensive income	106,627	141,175
Net income attributable to redeemable noncontrolling interests	(29,899)	(34,327)
Comprehensive loss attributable to redeemable noncontrolling interests	(29,899)	(34,327)
Comprehensive income attributable to RenaissanceRe	76,728	106,848
Consolidating Adjustments
Condensed Financial Statements, Captions [Line Items]
Net income	(56,896)	(128,765)
Change in net unrealized gains on investments	0	0
Comprehensive income	(56,896)	(128,765)
Net income attributable to redeemable noncontrolling interests	0	0
Comprehensive loss attributable to redeemable noncontrolling interests	0	0
Comprehensive income attributable to RenaissanceRe	$ (56,896)	$ (128,765)