Investments, Debt and Equity Securities Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Roll Forward]
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Beginning Balance	$ 308	$ 312	$ 299	$ 0
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Recovery	74	(3)	83	(88)
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Ending Balance	382	309	382	309
Cumulative Effect, Period of Adoption, Adjustment
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Roll Forward]
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Beginning Balance	$ 0	$ 0	$ 0	$ 397