Income Taxes - Provision for income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 43,595	$ 23,526
State	18,881	11,553	$ 5,010
Foreign	1,353	5,183	1,303
Current provision for income taxes	63,829	40,262	6,313
Deferred:
State		(205)	111
Foreign	(350)	(172)	(570)
Deferred provision for income taxes	(350)	(377)	(459)
Provision for income taxes	$ 63,479	$ 39,885	$ 5,854