Pension and Other Postretirement Benefits - Amounts to be Amortized From AOCI Over Next Fiscal Year (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial Loss	$ 3,173
Prior Service (Credit) Cost	(118)
Total	3,055
Domestic [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial Loss	2,283
Prior Service (Credit) Cost	59
Total	2,342
Domestic [Member] | Other Postretirement Benefit Plans Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial Loss	(58)
Prior Service (Credit) Cost	0
Total	58
Foreign [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial Loss	890
Prior Service (Credit) Cost	(177)
Total	$ 713