Pensions and Other Postretirement Benefit Plans (Schedule of (Gains)/Losses Recognized in Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Settlements/curtailments	$ (411)	$ (450)	$ (1,494)
Asset/liability loss/(gain)	(13,407)	1,796	(851)
Amortization of actuarial (loss)	(5,004)	(4,480)	(5,175)
Amortization of prior service cost/(credit)	4,474	4,420	4,454
Pension plans
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Settlements/curtailments	(411)	(450)	(1,494)
Asset/liability loss/(gain)	(8,053)	(2,794)	6,411
Amortization of actuarial (loss)	(2,412)	(2,253)	(2,219)
Amortization of prior service cost/(credit)	(14)	(68)	(34)
Other	(204)	0	0
Currency impact	670	316	(1,389)
Cost/(benefit) in Other comprehensive income	(10,424)	(5,249)	1,275
Other postretirement benefits
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Settlements/curtailments	0	0	0
Asset/liability loss/(gain)	(4,794)	4,685	(6,100)
Amortization of actuarial (loss)	(2,592)	(2,227)	(2,956)
Amortization of prior service cost/(credit)	4,488	4,488	4,488
Other	0	0	0
Currency impact	3	0	0
Cost/(benefit) in Other comprehensive income	$ (2,895)	$ 6,946	$ (4,568)