Net Investment Gains (Losses) (Net Investment Gains (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Fixed maturity securities, gains	$ 14,844	$ 3,157	$ 19,775	$ 8,403
Fixed maturity securities, losses	(9,234)	(3,377)	(14,081)	(6,895)
Net realized gains (losses) on investment sales	5,727	(6)	5,727	23,339
Change in unrealized gains (losses)	61,914	69,418	(92,552)	111,496
Investment funds	913	41	31,096	58
Real estate (2)	(7,137)	3,021	(7,824)	5,767
Loans receivable	0	0	0	(970)
Other	(5,374)	1,320	(23,773)	1,028
Net realized and unrealized gains (losses) on investments in earnings before allowance for expected credit losses	61,653	73,574	(81,632)	142,226
Fixed maturity securities	21,023	0	(10,727)	0
Loans receivable	(4,791)	0	(6,930)	0
Change in allowance for expected credit losses on investments	16,232	0	(17,657)	0
Net investment gains (losses)	77,885	73,574	(99,289)	142,226
Income tax (expense) benefit	(18,098)	(15,451)	22,476	(29,867)
After-tax net investment gains (losses)	59,787	$ 58,123	(76,813)	$ 112,359
Real estate investment, allowance	$ 8,000		$ 8,000