Fair Value Option (Gains And Losses Due To Changes In Fair Value Of Investments) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
(Losses) gains due to changes in fair value of investments	$ 37,127	$ (40,782)	$ 55,658	$ (45,667)
Fixed maturity securities [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
(Losses) gains due to changes in fair value of investments	28,871	(30,257)	40,434	(29,007)
Equity Securities [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
(Losses) gains due to changes in fair value of investments	8,666	(10,960)	15,573	(17,296)
Short-term investments [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
(Losses) gains due to changes in fair value of investments	$ (410)	$ 435	$ (349)	$ 636