Income taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income taxes
Income tax expense	$ 1,295	$ 1,375	$ 3,350	$ 3,030
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	108.70%	28.50%	40.50%	28.90%
Deferred compensation cost	$ 3,800