Other Income (expense) - (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Other Income And Expenses [Abstract]
Income from third party license fees	$ 304	$ 220
Foreign exchange (losses) gains, net	821	(237)
Gain on fixed asset disposals, net	2	9
Non-income tax refunds and other related credits	1,299	152
Pension and post retirement benefit costs, non-service components	(23,525)	(896)
Other non-operating income	180	148
Other non-operating expense	(256)	(31)
Total other income (expense), net	(21,175)	$ (635)
Defined Benefit Plan Effect Of Settlements And Curtailments On Accumulated Benefit Obligation	$ 22,700