Other Income (Expense) - (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other Income And Expenses [Abstract]
Income From Third Party License Fees	$ 250	$ 269
Foreign Exchange (Losses) Gains, Net	(229)	(214)
Gain (loss) on Fixed Asset Disposals, Net	52	15
Non-Income Tax Refunds and Other Related Credits	36	294
Pension and Post Retirement Benefit Costs Non-service Components	(576)	(566)
Other Nonoperating Income	157	131
Other Nonoperating Expense	(59)	(34)
Other (Expense) Income, Net	$ (369)	$ (105)