Components of income tax provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Deferred expense (benefit)	$ 389	$ (1,600)	$ (391)
Income tax provision	4,267	2,453	2,359
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Federal	3,340	3,487	2,406
State	538	566	344
Current provision	3,878	4,053	2,750
Federal	327	(1,335)	(317)
State	62	(265)	(74)
Deferred expense (benefit)	389	(1,600)	(391)
Income tax provision	$ 4,267	$ 2,453	$ 2,359