Income taxes - Schedule of Activity Related to Unrecognized Tax Benefits, Excluding Federal Tax Benefit of State Tax Deductions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Change in unrecognized tax benefits
Balance at beginning of year	$ 8,196	$ 7,435	$ 8,050
Additions for tax positions of prior years	0	1,363	630
Settlements	(9)	0	0
Reductions due to lapse of statutes of limitations	(462)	(602)	(1,245)
Balance as of end of year	$ 7,725	$ 8,196	$ 7,435