Net Investment Gains (Losses) (Net Investment Gains (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Fixed maturity securities, gains	$ 3,811	$ 2,100	$ 23,586	$ 10,503
Fixed maturity securities, losses	(39,162)	(4,984)	(53,243)	(11,879)
Net realized (losses) gains on investment sales	(176)	(11)	5,551	23,328
Change in unrealized gains (losses)	30,693	4,226	(61,859)	115,722
Investment funds	203	(456)	31,299	(398)
Real estate	3,841	417	(3,983)	6,184
Loans receivable	0	0	0	(970)
Other	(6,982)	173	(30,755)	1,201
Net realized and unrealized (losses) gains on investments in earnings before allowance for expected credit losses	(7,772)	1,465	(89,404)	143,691
Fixed maturity securities	43,874	0	33,147	0
Loans receivable	2,876	0	(4,054)	0
Change in allowance for expected credit losses on investments	46,750	0	29,093	0
Net investment gains (losses)	38,978	1,465	(60,311)	143,691
Income tax (expense) benefit	(8,855)	(308)	13,622	(30,175)
After-tax net investment gains (losses)	$ 30,123	$ 1,157	$ (46,689)	$ 113,516