Other Income (expense) - (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Other Income And Expenses [Abstract]
Income From Third Party License Fees	$ 193	$ 189	$ 413	$ 439
Foreign Exchange (Losses) Gains, Net	(144)	(493)	(381)	(722)
Gain (loss) on Fixed Asset Disposals, Net	30	547	39	599
Non-Income Tax Refunds and Other Related Credits	813	505	965	541
Pension and Post Retirement Benefit Costs Non-service Components	(895)	(569)	(1,791)	(1,145)
Other Nonoperating Income	74	102	222	259
Other Nonoperating Expense	(28)	(20)	(59)	(79)
Total Other (Expense) Income, Net	$ 43	$ 261	$ (592)	$ (108)
Property Plant And Equipment Additional Disclosures				Gain on fixed asset disposals, net, during the three and six months ended June 30, 2018 includes a $0.6 million gain on the sale of an available-for-sale asset related to the Combination.