Investments (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) security item	Dec. 31, 2019 USD ($) security item
Schedule of Available-for-sale Securities [Line Items]
Investments exceeding 10% of stockholder's equity | item	0	0
Gross gains on investments	$ 22,800	$ 5,000
Realized gains on sale of investments	21,000	4,100
Gross losses on investments	20,700	500
Realized losses on sale of investments	20,200	100
Proceeds from sale of investment securities	155,000	13,000
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Other-than-temporary impairment	1,692	0
Gain (loss) on investments	$ 2,125	$ 4,464
Number of securities sold | security	1	6
Realized gains on sale of securities		$ 4,100
Realized gain (loss) on sale of securities	$ 0
Securities pledged for the benefit of various state insurance departments and reinsurers	$ 29,700	$ 28,900
Equity Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Number of debt securities with unrealized loss | security	13	9
Number of debt securities with unrealized loss, less than 12 months | security	6	7
Number of debt securities with unrealized loss, greater than 12 months | security	7	2
Debt Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Number of debt securities with unrealized loss | security	81	61
Number of debt securities with unrealized loss, less than 12 months | security	64	41
Number of debt securities with unrealized loss, greater than 12 months | security	17	20