Calculation of earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Net income	$ 4,336	$ 3,453	$ 11,750	$ 12,332
Less: Undistributed earnings allocated to participating securities	(72)	(53)	(207)	(184)
Net income allocated to common stock	4,264	3,400	11,543	12,148
Weighted-average common shares issued	5,784	5,724	5,765	5,706
Less: Unvested restricted stock awards	(97)	(90)	(101)	(85)
Weighted average common shares outstanding used to calculate basic earnings per common share	5,687	5,634	5,663	5,621
Add: Dilutive effect of stock options	26	52	33	39
Weighted-average common shares outstanding used to calculate diluted earnings per common share	$ 5,713	$ 5,686	$ 5,696	$ 5,660
Earnings per common share (basic)	$ 0.75	$ 0.60	$ 2.04	$ 2.16
Earnings per common share (diluted)	$ 0.75	$ 0.60	$ 2.03	$ 2.15