Noncontrolling Interests (Schedule Of Redeemable Noncontrolling Interest) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Activity in redeemable noncontrolling interest
Beginning balance			$ 1,045,964
Net income (loss) attributable to redeemable noncontrolling interest	$ 30,635	$ 12,167	75,226	$ 51,829
Ending balance	1,122,403		1,122,403		$ 1,045,964
DaVinciRe Holdings Ltd.
Activity in redeemable noncontrolling interest
Beginning balance	926,141	867,734	930,955	1,037,306	1,037,306
Redemption of shares from redeemable noncontrolling interest	(986)	(813)	(91,804)	(208,711)
Sale of shares to redeemable noncontrolling interest	0	0	43,040	0
Net income (loss) attributable to redeemable noncontrolling interest	28,288	12,345	71,252	50,671
Ending balance	953,443	879,266	953,443	879,266	930,955
RenaissanceRe Medici Fund Ltd.
Activity in redeemable noncontrolling interest
Beginning balance	155,196	100,697	115,009	94,402	94,402
Redemption of shares from redeemable noncontrolling interest	(6,400)	(2,423)	(7,340)	(17,107)	(20,100)
Sale of shares to redeemable noncontrolling interest	17,817	11,450	57,317	31,093	36,100
Net income (loss) attributable to redeemable noncontrolling interest	2,347	(178)	3,974	1,158
Ending balance	$ 168,960	$ 109,546	$ 168,960	$ 109,546	$ 115,009