Earnings per share (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Basic weighted average common shares outstanding (in shares)	11,897,813	11,789,570	11,679,520
Dilutive shares (in shares)	21,695	40,248	70,942
Diluted weighted average common shares outstanding (in shares)	11,919,508	11,829,818	11,750,462
Antidilutive shares excluded from EPS (in shares)	75,870	52,219	29,260