Other Income (Expense) - (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Income And Expenses [Abstract]
Income From Third Party License Fees	$ 202	$ 177	$ 471	$ 449
Foreign Exchange (Losses) Gains, Net	249	2	35	314
Gain (loss) on Fixed Asset Disposals, Net	13	(1)	28	4
Non-Income Tax Refunds and Other Related Credits	324	40	618	61
Pension and Post Retirement Benefit Costs Non-service Components	(2,436)	(608)	(3,002)	(1,212)
Other Nonoperating Income	110	87	241	211
Other Nonoperating Expense	(33)	(34)	(67)	(62)
Other (Expense) Income, Net	$ (1,571)	$ (337)	$ (1,676)	$ (235)