Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		$ 417,172
Other comprehensive income (loss)		5,157	$ 3,428	$ (5,473)
Amounts reclassified from accumulated other comprehensive loss	[1]	715	986	826
Ending Balance		476,809	417,172
Total Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(18,113)	(22,527)	(17,880)
Ending Balance		(12,241)	(18,113)	(22,527)
Cumulative Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(9,218)	(12,485)	(8,313)
Other comprehensive income (loss)		6,922	3,267	(4,172)
Ending Balance		(2,296)	(9,218)	(12,485)
Pension Liability Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(8,895)	(10,042)	(9,567)
Other comprehensive income (loss)		(1,765)	161	(1,301)
Amounts reclassified from accumulated other comprehensive loss	[1]	715	986	826
Ending Balance		$ (9,945)	$ (8,895)	$ (10,042)

[1] The amounts reclassified from accumulated other comprehensive loss were included in other income (expense) in the consolidated statements of operations.