Noncontrolling Interests (Schedule of Redeemable Noncontrolling Interest) (Details) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
Jun. 01, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Activity in redeemable noncontrolling interest
Beginning balance				$ 2,051,700
Net income attributable to redeemable noncontrolling interest		$ 71,812	$ 54,483	142,034	$ 84,382
Ending balance		2,712,466		2,712,466
DaVinciRe Holdings Ltd.
Activity in redeemable noncontrolling interest
Beginning balance		1,097,245	1,032,543	1,034,946	1,011,659
Redemption of shares from redeemable noncontrolling interest, net of adjustments		(698)	(370)	(932)	(439)
Sale of shares to redeemable noncontrolling interests	$ 349,200	274,699	0	274,699	0
Net income attributable to redeemable noncontrolling interest		59,855	50,252	122,388	71,205
Ending balance		1,431,101	1,082,425	1,431,101	1,082,425
RenaissanceRe Medici Fund Ltd.
Activity in redeemable noncontrolling interest
Beginning balance		406,958	392,821	416,765	284,847
Redemption of shares from redeemable noncontrolling interest, net of adjustments		(21,556)	(42,792)	(37,440)	(43,503)
Sale of shares to redeemable noncontrolling interests		128,809	56,743	132,405	156,482
Net income attributable to redeemable noncontrolling interest		1,704	4,231	4,185	13,177
Ending balance		515,915	411,003	515,915	411,003
Vermeer Reinsurance Ltd.
Activity in redeemable noncontrolling interest
Beginning balance		605,197	0	599,989	0
Sale of shares to redeemable noncontrolling interests		150,000	0	150,000	0
Net income attributable to redeemable noncontrolling interest		10,253	0	15,461	0
Ending balance		$ 765,450	$ 0	$ 765,450	$ 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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