Segments and Enterprise-Wide Disclosures - Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Enterprise-Wide Disclosures
Revenue		$ 392,285	$ 366,091	$ 394,170
Long-lived assets		12,522	14,612	14,818
Deferred tax assets, net of valuation allowance		4,946	393	453
United States [Member]
Enterprise-Wide Disclosures
Revenue		215,637	203,495	241,038
Long-lived assets		2,081	1,710	3,534
Deferred tax assets, net of valuation allowance		4,612		78
Belgium [Member]
Enterprise-Wide Disclosures
Revenue	[1]	68,109	59,851	52,468
Luxembourg [Member]
Enterprise-Wide Disclosures
Revenue	[2]	72,699	66,411	64,852
Long-lived assets	[2]	3,125	3,879	3,965
Other Countries [Member]
Enterprise-Wide Disclosures
Revenue		35,840	36,334	35,812
Long-lived assets		1,653	2,182	2,195
Foreign Countries [Member]
Enterprise-Wide Disclosures
Revenue		176,648	162,596	153,132
France [Member]
Enterprise-Wide Disclosures
Long-lived assets	[3]	5,663	6,841	5,124
Europe [Member]
Enterprise-Wide Disclosures
Deferred tax assets, net of valuation allowance		$ 334	$ 393	$ 375

[1] Revenue for our Belgium operations has been disclosed separately as it exceeds 10% of consolidated revenue in at least one of the years presented.

[2] Revenue and long-lived assets for our Luxembourg operations have been disclosed separately as they exceed 10% of the consolidated balances in at least one of the years presented

[3] Long-lived assets for our France operations have been disclosed separately as they exceed 10% of consolidated long-lived assets in at least one of the years presented.