Realized and Unrealized Investment Gains and Losses (Realized and Unrealized Investment Gains (Losses) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, No Previous Impairment	$ 33,300,000	$ 0	$ 6,000,000
Fixed maturity securities, Gains	23,755,000	39,113,000	48,860,000
Fixed maturity securities, Losses	(4,065,000)	(4,420,000)	(14,670,000)
Investment funds	93,529,000	96,204,000	10,976,000
Gain (Loss) on Sale of Properties	0	85,659,000	0
Other gains	2,775,000	0	12,185,000
Net realized gains on investments sales	125,633,000	254,852,000	127,586,000
Other-than-temporary impairments	(33,309,000)	0	(6,042,000)
Net other-than-temporary impairments	(33,309,000)	0	(6,042,000)
Equity securities available for sale	9,639,000	38,296,000	70,235,000
Net investment gains	92,324,000	254,852,000	121,544,000
Income tax expense	(32,313,000)	(89,198,000)	(47,426,000)
Total after-tax investment gains	60,011,000	165,654,000	$ 74,118,000
Fixed Income Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, No Previous Impairment	9,000,000	$ 0
Equity securities available for sale
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, No Previous Impairment	$ 24,300,000