Realized and Unrealized Investment Gains (Losses) (Realized and Unrealized Investment Gains (Losses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Jun. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Realized And Unrealized Investment Gains (Losses)
Fixed maturity securities, gains	$ 19,500	$ 4,439	$ 39,643	$ 25,046
Fixed maturity securities, losses	(739)	(1,937)	(12,205)	(4,243)
Equity securities available for sale	25,158	14,447	58,489	58,873
Investment funds	(34)	277	11,003	3,778
Other	(16)	0	(34)	1,535
Realized Gain (Loss) on Investments, Including Equity Method Investments, Excluding Other than Temporary Impairments and Allowances	43,869	17,226	96,896	84,989
Decrease in valuation allowance	0	5,000	0	13,998
Other-than-temporary impairments	0	0	0	(4,984)
Change in valuation allowance, net of other-than-temporary impairments	0	5,000	0	9,014
Net investment gains	43,869	22,226	96,896	94,003
Income tax expense	(15,355)	(7,415)	(33,914)	(32,260)
Total after-tax realized investment gains	$ 28,514	$ 14,811	$ 62,982	$ 61,743