Noncontrolling Interests (Schedule of Redeemable Noncontrolling Interest Activity) (Details) - USD ($) $ in Thousands		12 Months Ended
Jun. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Activity in redeemable noncontrolling interest
Beginning balance		$ 2,051,700
Comprehensive income:
Net income attributable to redeemable noncontrolling interests		201,469	$ 41,553	$ (132,282)
Ending balance		3,071,308	2,051,700
DaVinciRe Holdings Ltd.
Activity in redeemable noncontrolling interest
Beginning balance		1,034,946	1,011,659
Redemption of shares from redeemable noncontrolling interests, net of adjustments		(1,148)	(4,351)
Sale of shares to redeemable noncontrolling interests	$ 349,200	274,699	0
Comprehensive income:
Net income attributable to redeemable noncontrolling interests		127,084	27,638	(134,860)
Ending balance		1,435,581	1,034,946	1,011,659
RenaissanceRe Medici Fund Ltd.
Activity in redeemable noncontrolling interest
Beginning balance		416,765	284,847
Redemption of shares from redeemable noncontrolling interests, net of adjustments		(47,401)	(90,490)
Sale of shares to redeemable noncontrolling interests		236,989	208,482
Comprehensive income:
Net income attributable to redeemable noncontrolling interests		25,759	13,926	2,578
Ending balance		632,112	416,765	284,847
Vermeer Reinsurance Ltd.
Activity in redeemable noncontrolling interest
Beginning balance		599,989	0
Sale of shares to redeemable noncontrolling interests		355,000	600,000
Comprehensive income:
Net income attributable to redeemable noncontrolling interests		48,626	(11)	0
Ending balance		$ 1,003,615	$ 599,989	$ 0

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Decrease in noncontrolling interest (for example, but not limited to, redeeming or purchasing the interests of noncontrolling shareholders, issuance of shares (interests) by the non-wholly owned subsidiary to the parent entity for other than cash, and a buyback of shares (interest) by the non-wholly owned subsidiary from the noncontrolling interests).

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- Definition

Amount of Net Income (Loss) attributable to redeemable noncontrolling interest.

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- Definition

Amount of increase in noncontrolling interest from subsidiary issuance of equity interests to noncontrolling interest holders.

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- Definition

As of the reporting date, the aggregate carrying amount of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.

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