Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 738,695,000	$ 666,466,000	$ 720,940,000	$ 686,257,000
Other comprehensive income (loss)	0	(1,000)	6,000	(26,000)
Ending Balance	789,837,000	666,511,000	789,837,000	666,511,000
Foreign  Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			29,000	9,000
Foreign currency translation adjustments, net of tax			6,000	(26,000)
Other comprehensive income (loss)			6,000	(26,000)
Ending Balance	$ 35,000	$ (17,000)	35,000	(17,000)
Other comprehensive income (loss), before reclassifications, tax			$ (2,000)	$ 9,000