Pensions - Schedule of Amounts in Accumulated Other Comprehensive Income Loss To Be Recognized Over Next Fiscal Year (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year	$ 294
Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year	1,378
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year	292
Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year	(609)
Pension Plan [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year	(20)
Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year	(2,383)
Pension Plan [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year	(240)
Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year	$ (2,553)