Restructuring Expenses - Schedule of Restructuring Activities and Related Reserves (Details) - USD ($) $ in Thousands	3 Months Ended
Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Restructuring Reserve
Beginning Provision	$ 5,726	$ 7,278	$ 8,658
Charges	2,710	486	89
Cash paid	(2,898)	(2,031)	(1,360)
Foreign currency translation adjustment	(219)	(7)	(109)
Ending Provision	5,319	5,726	7,278
Personnel expenses
Restructuring Reserve
Beginning Provision	2,762	2,248	2,334
Charges	1,755	485	61
Cash paid	(1,146)	0	(103)
Foreign currency translation adjustment	(110)	29	(44)
Ending Provision	3,261	2,762	2,248
Demolition and Removal costs
Restructuring Reserve
Beginning Provision	669	1,281	2,541
Charges	0	0	9
Cash paid	(21)	(621)	(1,234)
Foreign currency translation adjustment	(29)	9	(35)
Ending Provision	619	669	1,281
Ground remediation costs
Restructuring Reserve
Beginning Provision	1,938	2,917	2,939
Charges	0	0	19
Cash paid	(742)	(941)	(19)
Foreign currency translation adjustment	(65)	(38)	(22)
Ending Provision	1,131	1,938	2,917
Other
Restructuring Reserve
Beginning Provision	357	832	844
Charges	955	1	0
Cash paid	(989)	(469)	(4)
Foreign currency translation adjustment	(15)	(7)	(8)
Ending Provision	$ 308	$ 357	$ 832

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of foreign currency translation gain (loss) which decreases (increases) the restructuring reserve.

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