Other Income (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Income and Expenses [Abstract]
Income from third party license fees	$ 999	$ 1,035	$ 862
Foreign exchange gains (losses), net	(6,082)	223	(807)
Gain (loss) on fixed asset disposals, net	(871)	58	657
Non-income tax refunds and other related credits	3,345	1,118	668
Pension and post retirement benefit costs, non-service components	(21,592)	(2,805)	(2,285)
Insurance solvency recovery	18,144	60	90
Other Operating Income Expense Net	439	57	173
Other expense, net	(5,618)	(254)	(642)
Narrative [Abstract]
Foreign Currency Transaction Loss Before Tax	400	$ 1,000	400
Foreign Currency Transaction Gain, before Tax			400
Gain (loss) on disposition of assets	(600)		$ 600
Defined Benefit Plan Premium Refund	1,600
Pension Settlement Charge	$ 22,700