Other Income (Expense) - (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Other Income And Expenses [Abstract]
Income From Third Party License Fees	$ 220	$ 250
Foreign Exchange (Losses) Gains, Net	(237)	(229)
Gain (loss) on Fixed Asset Disposals, Net	9	52
Non-Income Tax Refunds and Other Related Credits	152	36
Pension and Post Retirement Benefit Costs Non-service Components	(896)	(576)
Other Nonoperating Income	148	157
Other Nonoperating Expense	(31)	(59)
Other (Expense) Income, Net	$ (635)	$ (369)