Noncontrolling Interests (Schedule of Redeemable Noncontrolling Interest) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Activity in redeemable noncontrolling interest
Beginning balance	$ 2,051,700
Net income attributable to redeemable noncontrolling interest	70,222	$ 29,899
Ending balance	2,109,400
DaVinciRe Holdings Ltd.
Activity in redeemable noncontrolling interest
Beginning balance	1,034,946	1,011,659
Redemption of shares from redeemable noncontrolling interest, net of adjustments	(234)	(69)
Net income attributable to redeemable noncontrolling interest	62,533	20,953
Ending balance	1,097,245	1,032,543
RenaissanceRe Medici Fund Ltd.
Activity in redeemable noncontrolling interest
Beginning balance	416,765	284,847
Redemption of shares from redeemable noncontrolling interest, net of adjustments	(15,884)	(711)
Sale of shares to redeemable noncontrolling interests	3,596	99,739
Net income attributable to redeemable noncontrolling interest	2,481	8,946
Ending balance	406,958	392,821
Vermeer Reinsurance Ltd.
Activity in redeemable noncontrolling interest
Beginning balance	599,989	0
Net income attributable to redeemable noncontrolling interest	5,208	0
Ending balance	$ 605,197	$ 0

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

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

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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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