Fair Value Option (Gains And Losses Due To Changes In Fair Value Of Investments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Gains and losses due to changes in fair value of investments	$ (24,788)	$ 20,597	$ 24,555	$ 41,434
Fixed maturity securities [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Gains and losses due to changes in fair value of investments	9,812	33,879	30,815	24,309
Equity securities [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Gains and losses due to changes in fair value of investments	(33,972)	(13,237)	(5,476)	17,151
Short-term Investments [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Gains and losses due to changes in fair value of investments	$ (628)	$ (45)	$ (784)	$ (26)