Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 789,837	$ 666,511	$ 720,940	$ 686,257
Other comprehensive income (loss)	(17)	17	(11)	(9)
Ending Balance	821,110	688,012	821,110	688,012
Foreign  Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			29	9
Foreign currency translation adjustments, net of tax			(11)	(9)
Other comprehensive income (loss)			(11)	(9)
Ending Balance	$ 18	$ 0	18	0
Other comprehensive income (loss), before reclassifications, tax			$ 4	$ 3