Consolidation and Basis of Presentation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net investment gains	$ 1,766	$ 3,415	$ 5,560	$ 4,831
Earnings before Federal income taxes	37,704	62,697	83,311	141,017
Federal income taxes	6,939	12,798	16,362	28,989
Net earnings	30,765	49,899	66,949	112,028
Unrealized Gains and Losses on Available-for-sale Securities | Amount Reclassified From Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net investment gains	1,766	4,823	5,224	6,239
Earnings before Federal income taxes	1,766	4,823	5,224	6,239
Federal income taxes	371	1,013	1,097	1,310
Net earnings	$ 1,395	$ 3,810	$ 4,127	$ 4,929