Income Taxes - Valuation allowances, uncertain tax positions and accrued interest and penalties (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Valuation allowance
Deferred tax assets, valuation allowance	$ 19,992	$ 34,979	$ 19,992
Increase (decrease) in valuation allowance	2,700	15,000
Interest and penalties
Accrued interest or penalties for income tax liabilities	100	100	100	$ 200
Change in reserve for uncertain tax benefits
Reserve at beginning of year		500	2,923	427
Increases related to prior year tax positions		12	277	2,500
Decreases related to prior year tax positions			(37)
Lapse of statute of limitations				(4)
Settlement			(2,663)
Total	$ 500	512	$ 500	$ 2,923
Uncertain tax positions
Uncertain tax positions that would impact of effective tax rate		500
Unrecognized tax benefits estimated decrease		$ 500