Income Taxes - Sources of Difference and Tax Effects (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Sources of the difference and the tax effects
Federal income tax expense, at statutory rate	$ 12,512	$ 34,496	$ 36,702
Investment income, net	(559)	(1,060)	(1,394)
State taxes, net	58	11	211
Nondeductible expenses	468	613	697
Tax related to share-based stock compensation	222	(101)	(298)
Other, net	319	(399)	641
Total income tax expense	$ 13,020	$ 33,560	$ 36,559