Income Taxes - Current and Deferred Components of Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Federal income tax
Current									$ 6,058	$ 4,923	$ 3,978
Deferred									999	(262)	336
Federal income tax expense									7,057	4,661	4,314
State franchise tax									587	460	421
Income tax expense	$ 2,053	$ 1,915	$ 1,826	$ 1,850	$ 1,285	$ 1,379	$ 1,256	$ 1,201	$ 7,644	$ 5,121	$ 4,735