Non-pension Post-retirement Benefits (Amounts in Accumulated Other Comprehensive Loss to be Recognized During 2018) (Details) - Non-pension Post-retirement Benefit Plans $ in Thousands	Dec. 31, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	$ (276)
Prior service cost (credit)	(282)
Total cost (credit)	(558)
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	(210)
Prior service cost (credit)	(282)
Total cost (credit)	(492)
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	(66)
Prior service cost (credit)	0
Total cost (credit)	$ (66)