Calculation of earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Net income	$ 3,845	$ 4,353	$ 7,414	$ 8,879
Less: Undistributed earnings allocated to participating securities	(73)	(66)	(134)	(130)
Net income allocated to common stock	3,772	4,287	7,280	8,749
Weighted-average common shares issued	5,776	5,704	5,755	5,698
Less: Unvested restricted stock awards	(110)	(86)	(104)	(84)
Weighted average common shares outstanding used to calculate basic earnings per common share	5,666	5,620	5,651	5,614
Add: Dilutive effect of stock options	33	38	48	36
Weighted-average common shares outstanding used to calculate diluted earnings per common share	$ 5,699	$ 5,658	$ 5,699	$ 5,650
Earnings per common share (basic)	$ 0.67	$ 0.76	$ 1.29	$ 1.56
Earnings per common share (diluted)	$ 0.66	$ 0.76	$ 1.28	$ 1.55