Realized and Unrealized Investment Gains (Losses) (Realized and Unrealized Investment Gains (Losses) (Details) (USD $)	3 Months Ended						6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Mar. 31, 2011		Jun. 30, 2012
Realized And Unrealized Investment Gains (Losses)
Fixed maturity securities, gains	$ 5,652,000		$ 8,957,000		$ 14,837,000		$ 20,607,000
Fixed maturity securities, losses	(1,763,000)		(1,016,000)		(2,509,000)		(2,306,000)
Equity securities available for sale	18,188,000		14,289,000		38,221,000		44,426,000
Other	18,000		0		0		1,535,000
Sales of investment funds	2,191,000		1,060,000		2,025,000		3,501,000
Provision for OTTI	0	[1]	(400,000)	[1]	(400,000)	[1]	4,014,000	[1]
Net investment gains	24,286,000		22,890,000		52,174,000		71,777,000
Income tax expense	(8,436,000)		(8,554,000)		(19,048,000)		(24,845,000)
Total net investment gains	15,850,000		14,336,000		33,126,000		46,932,000
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	123,000		0		0		6,773,000
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, No Previous Impairment							$ 3,000,000

[1] For the six months ended June 30, 2012, this represents a valuation allowance reduction of $7 million, partially offset by an other-than-temporary impairment of $3 million