Commitments and Contingencies - Activity in Recorded Environmental Liabilities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	$ 39,808
Expenditures	(3,564)
Accretion of discount	669
Additions and changes in estimates	16,236
Foreign currency translation adjustments	(346)
Balance at end of period	$ 39,808	$ 52,803
Less amounts reported in Accrued expenses		5,012
Amounts reported in Other noncurrent liabilities		$ 47,791