Basic and diluted earnings per common share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Earnings per common share:
Weighted average common shares outstanding during the period – shares used for basic earnings per common share	9,420	9,386	9,355
Common shares issuable under share based payments plans which are potentially dilutive	41	49	42
Common shares used for diluted earnings per common share	9,461	9,435	9,397
Net income attributable to the Company	$ 5,302	$ 4,565	$ 28,215
-basic	$ 0.56	$ 0.49	$ 3.02
-diluted	$ 0.56	$ 0.48	$ 3.00