Summary of Significant Accounting Policies - Schedule of Unrealized Gains and Losses on Available-for-Sale Securities Reclassified out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net investment gains	$ 6,355	$ 14,950	$ 21,071
Net OTTI losses recognized in earnings	0	0	0
Earnings before Federal income taxes	126,034	227,257	112,068
Federal income taxes	24,890	46,576	19,756
Net earnings	101,144	180,681	92,312
Accumulated Other Comprehensive Income | Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other net investment gains	5,111	16,372	5,677
Net OTTI losses recognized in earnings	0	0	0
Earnings before Federal income taxes	5,111	16,372	5,677
Federal income taxes	1,073	3,438	1,192
Net earnings	$ 4,038	$ 12,934	$ 4,485