Segment and Other Operating Information - Federal Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Federal income taxes	$ 6,939	$ 12,798	$ 16,362	$ 28,989
Segments
Segment Reporting Information [Line Items]
Federal income taxes	6,568	12,080	15,194	27,974
Segment Reconciling Items
Segment Reporting Information [Line Items]
Taxes on realized gains on investments	$ 371	$ 718	$ 1,168	$ 1,015