Defined Benefit Pension Plans - Change in Benefit Obligation and Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at January 1,	$ 114,218	$ 105,570
Service cost	4,027	3,711	$ 4,034
Interest cost	1,817	2,278	2,324
Actuarial (gain) loss	9,323	8,798
Benefits paid	2,820	2,970
Foreign currency exchange rate changes	9,594	(1,984)
Curtailment	(589)	(36)
Settlement	(78)	(234)
Other	(2,760)	(915)
Benefit obligation at December 31,	132,732	114,218	105,570
Fair value of plan assets at January 1,	12,665	11,890
Actual return on plan assets	389	1,134
Company contributions	349	289
Benefits paid	298	411
Foreign currency exchange rate changes	(177)	(237)
Release for Divestiture	(2,722)	0
Fair value of plan assets at December 31,	10,206	12,665	$ 11,890
Net pension benefit obligation at fair value	$ 122,526	$ 101,553