Restructuring Expenses - Schedule of Restructuring Activities and Related Reserves (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020
Restructuring Reserve
Beginning Provision	$ 2,572	$ 3,221	$ 4,765
Charges	0	0	0
Cost charged against liabilities (assets)	0	0	0
Cash paid	(862)	(708)	(1,432)
Foreign currency translation adjustment	116	59	(113)
Ending Provision	1,826	2,572	3,221
Personnel expenses
Restructuring Reserve
Beginning Provision	2,373	2,805	3,400
Charges	0	0	0
Cost charged against liabilities (assets)	0	0	0
Cash paid	(814)	(486)	(514)
Foreign currency translation adjustment	107	53	(81)
Ending Provision	1,666	2,373	2,805
Demolition and Removal costs
Restructuring Reserve
Beginning Provision	75	147	561
Charges	0	0	0
Cost charged against liabilities (assets)	0	0	0
Cash paid	0	(74)	(402)
Foreign currency translation adjustment	3	2	(11)
Ending Provision	79	75	147
Ground remediation costs
Restructuring Reserve
Beginning Provision	75	221	488
Charges	0	0	0
Cost charged against liabilities (assets)	0	0	0
Cash paid	(48)	(148)	(252)
Foreign currency translation adjustment	3	2	(14)
Ending Provision	30	75	221
Other
Restructuring Reserve
Beginning Provision	49	48	317
Charges	0	0	0
Cost charged against liabilities (assets)	0	0	0
Cash paid	0	0	(263)
Foreign currency translation adjustment	2	1	(6)
Ending Provision	$ 51	$ 49	$ 48