Investments (Net Realized Gains (Losses) on Disposals) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Realized Gains (Losses) on Disposals Excluding OTTI [Line Items]
HTM gains (losses)	$ 1	$ 0	$ 2	$ 1
CMLs gains	1	0	2	0
CMLs losses	0	0	0	0
Equity securities Gains	0	21,630	0	24,868
Equity securities Losses	0	(28)	(3)	(135)
Short-term investments Gains	18	2	355	18
Short-term investments Losses	(7)	(38)	(198)	(39)
Other investments Gains	0	0	0	7
Other investments Losses	0	0	(5)	(30)
Net realized investment gains on disposals	573	20,425	7,288	26,752
Gain (Loss) on Investments [Member]
Schedule of Realized Gains (Losses) on Disposals Excluding OTTI [Line Items]
HTM gains (losses)	0	0	0	(15)
Available-for-sale Securities
Schedule of Realized Gains (Losses) on Disposals Excluding OTTI [Line Items]
AFS fixed income securities Gains	2,955	1,078	14,770	5,565
AFS fixed income securities Losses	$ (2,395)	$ (2,219)	$ (7,635)	$ (3,488)