Pension and Postretirement Benefits (Amounts Recognized in Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Postretirement Medical Benefits
Defined Benefit Plan Disclosure [Line Items]
Unrecognized net gain (loss)	$ 1,512	$ 3,365
Unrecognized prior service cost	(856)	(940)
Accumulated other comprehensive loss, net of tax	656	2,425	$ 880
United States | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Unrecognized net gain (loss)	(48,578)	(61,129)
Unrecognized prior service cost	(932)	(889)
Accumulated other comprehensive loss, net of tax	(49,510)	(62,018)	(49,790)
Foreign Plan | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Unrecognized net gain (loss)	(85,891)	(58,697)
Unrecognized prior service cost	(3,446)	(3,391)
Accumulated other comprehensive loss, net of tax	$ (89,337)	$ (62,088)	$ (67,872)