Noncontrolling Interests (Schedule of Redeemable Noncontrolling Interest) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Activity in redeemable noncontrolling interest
Beginning balance			$ 3,388,319
Net income (loss) attributable to redeemable noncontrolling interest	$ (198,495)	$ 19,301	(131,801)	$ 236,120
Ending balance	3,458,298		3,458,298
DaVinciRe Holdings Ltd.
Activity in redeemable noncontrolling interest
Beginning balance	1,642,656	1,621,300	1,560,693	1,435,581
Redemption of shares from redeemable noncontrolling interest, net of adjustments	(637)	(1)	(157,863)	2,447
Sale of shares to redeemable noncontrolling interests, net of adjustments			250,000
Net income (loss) attributable to redeemable noncontrolling interest	(202,362)	(26,616)	(158,030)	146,664
Ending balance	1,443,589	1,594,683	1,443,589	1,594,683
DaVinciRe Holdings Ltd. \| Third-Party Investors And RenaissanceRe
Activity in redeemable noncontrolling interest
Sale of shares to redeemable noncontrolling interests, net of adjustments	3,932	0	198,789	9,991
Medici
Activity in redeemable noncontrolling interest
Beginning balance	880,320	682,118	717,999	632,112
Redemption of shares from redeemable noncontrolling interest, net of adjustments	(22,921)	(31,174)	(30,666)	(80,412)
Sale of shares to redeemable noncontrolling interests, net of adjustments	20,000	12,092	191,520	102,863
Net income (loss) attributable to redeemable noncontrolling interest	6,526	33,963	5,072	42,436
Ending balance	883,925	696,999	883,925	696,999
Vermeer Reinsurance Ltd.
Activity in redeemable noncontrolling interest
Beginning balance	1,133,443	1,083,681	1,109,627	1,003,615
Sale of shares to redeemable noncontrolling interests, net of adjustments	0	0	0	45,000
Net income (loss) attributable to redeemable noncontrolling interest	(2,659)	11,954	21,157	47,020
Ending balance	$ 1,130,784	$ 1,095,635	$ 1,130,784	$ 1,095,635

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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