Realized and Unrealized Investment Gains and Losses (Realized and Unrealized Investment Gains (Losses)) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Realized and Unrealized Investment Gains (Losses) [Abstract]
Fixed maturity securities, Gains	$ 23,900,000	$ 26,752,000	$ 28,217,000
Fixed maturity securities, Losses	(13,636,000)	(13,733,000)	(5,342,000)
Net realized gains on investment sales	23,306,000	435,150,000	154,539,000
Change in unrealized gains (losses)	85,292,000	(320,413,000)	0
Investment funds	(2,825,000)	(212,000)	125,423,000
Real estate	5,965,000	27,816,000	12,880,000
Loans receivable	(970,000)	2,838,000	0
Other	(329,000)	1,977,000	20,141,000
Net realized and unrealized gains on investments in earnings before OTTI	120,703,000	160,175,000	335,858,000
Other-than-temporary impairments	0	5,687,000	0
Net investment gains	120,703,000	154,488,000	335,858,000
Income tax expense	(25,348,000)	(32,442,000)	(117,550,000)
After-tax net realized and unrealized gains on investments in earnings	$ 95,355,000	$ 122,046,000	$ 218,308,000