Investments (Equity Securities) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Equity security	$ 22,657		$ 22,657		$ 22,102
Realized investment gains (losses), net	4,859	$ 1,448	5,151	$ 142
Stock Mutual Funds [Member]
Debt and Equity Securities, FV-NI [Line Items]
Equity security	3,473		3,473		3,174
Bond Mutual Funds [Member]
Debt and Equity Securities, FV-NI [Line Items]
Equity security	12,601		12,601		12,354
Common stock [Member]
Debt and Equity Securities, FV-NI [Line Items]
Equity security	1,137		1,137		1,143
Non-redeemable Preferred Stock [Member]
Debt and Equity Securities, FV-NI [Line Items]
Equity security	276		276		281
Nonredeemable Preferred Stock Fund Member [Member]
Debt and Equity Securities, FV-NI [Line Items]
Equity security	5,170		5,170		$ 5,150
Equity Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Realized investment gains (losses), net	$ 300	$ 1,300	$ 600	$ 200