Restructuring Costs - Severance Obligation (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
2019 Corporate Restructuring Obligations
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	$ 1,080	$ 0
Payments	(794)	(2,113)
Restructuring reserve, ending balance	492	853
2019 French Restructuring Obligation
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	1,922	0
Payments	(1,813)	(1,837)
Foreign currency impact	(45)	(42)
Restructuring reserve, ending balance	237	895
Employee Severance | 2019 Corporate Restructuring Obligations
Restructuring Reserve [Roll Forward]
Restructuring costs	206	2,966
Employee Severance | 2019 French Restructuring Obligation
Restructuring Reserve [Roll Forward]
Restructuring costs	$ 173	$ 2,774