Other Income (Expense) - (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Income And Expenses [Abstract]
Income From Third Party License Fees	$ 141	$ 264	$ 612	$ 713
Foreign Exchange Gains, Net	545	149	580	463
Gain on Fixed Asset Disposals, Net	22	3	50	7
Non-Income Tax Refunds and Other Related Credits	130	72	748	133
Pension and Post Retirement Benefit Costs Non-service Components	(537)	(524)	(3,539)	(1,736)
Other Nonoperating Income	47	54	288	265
Other Nonoperating Expense	(99)	(28)	(166)	(90)
Other Income (Expense), Net	$ 249	$ (10)	$ (1,427)	$ (245)