Realized and Unrealized Investment Gains (Losses) (Realized and Unrealized Investment Gains (Losses) (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Realized And Unrealized Investment Gains (Losses)
Fixed maturity securities, gains	$ 4,439,000		$ 10,212,000		$ 25,046,000		$ 25,049,000
Fixed maturity securities, losses	(1,937,000)		(2,207,000)		(4,243,000)		(4,716,000)
Equity securities available for sale	14,447,000		12,318,000		58,873,000		50,539,000
Other	0		0		1,535,000		0
Sales of investment funds	277,000		915,000		3,778,000		2,940,000
Provision for OTTI	5,000,000	[1]	0	[1]	9,014,000	[1]	(400,000)	[1]
Net investment gains	22,226,000		21,238,000		94,003,000		73,412,000
Income tax expense	(7,415,000)		(7,454,000)		(32,260,000)		(26,502,000)
Total net investment gains	14,811,000		13,784,000		61,743,000		46,910,000
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	(7,280,000)		(9,000)		(14,053,000)		541,000
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, No Previous Impairment					$ 5,000,000

[1] For the nine months ended September 30, 2012, this represents a change in valuation allowance of $14 million, partially offset by an other-than-temporary impairment of $5 million