Commitments and Contingencies - Activity in Recorded Environmental Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2018
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of period	$ 39,808
Expenditures	(2,612)
Accretion of discount	225
Additions and revisions of estimates	16,236
Foreign currency translation adjustments	786
Balance at end of period	$ 39,808	$ 54,443
Less amounts reported in Accrued expenses		5,060
Amounts reported in Other noncurrent liabilities		$ 49,383