Income Taxes - Reconciliation between applicable income taxes and statutory federal tax rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Tax amount
Taxes at statutory federal income tax rate	$ 10,958	$ 14,506	$ 12,289
Tax exempt income	(514)	(556)	(527)
State income taxes, net of federal benefits	2,297	2,973	2,522
Nondeductible items and other	(564)	(527)	(441)
Applicable income taxes	$ 12,177	$ 16,396	$ 13,843
Percentage of pretax income
Taxes at statutory federal income tax rate (as percentage)	21.00%	21.00%	21.00%
Tax exempt income (as percentage)	(1.00%)	(0.80%)	(0.90%)
State income taxes, net of federal benefits (as percentage)	4.40%	4.30%	4.30%
Nondeductible items and other (as percentage)	(1.10%)	(0.80%)	(0.80%)
Applicable income taxes (as percentage)	23.30%	23.70%	23.60%