Accumulated Other Comprehensive Income (Loss) (Components of OCI) (Details 1) - USD ($) $ in Thousands		3 Months Ended						9 Months Ended
		Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before tax		$ 21,562			$ (18,604)			$ 819	$ (23,403)
Other Comprehensive Income (Loss), income tax		(299)			518			(431)	1,512
Other Comprehensive Income (Loss), Net of Tax		21,263	$ 17,068	$ (37,943)	(18,086)	$ (12,095)	$ 8,290	388	(21,891)
Foreign Currency Translation Adjustment [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax								(541)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax								0
Other Comprehensive Income (Loss), before tax		20,430			(16,684)			(541)	(17,755)
Other Comprehensive Income (Loss), income tax		0			0			0	0
Other Comprehensive Income (Loss), Net of Tax		20,430			(16,684)			(541)	(17,755)
Pension and Other Postretirement Plans [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax								0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		975			(1,443)			2,924	(4,744)
Reclassification from AOCI, Current Period, Tax		(263)			390			(789)	1,281
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		712			(1,053)			2,135	(3,463)
Other Comprehensive Income (Loss), before tax		975			(1,443)			2,924	(4,744)
Other Comprehensive Income (Loss), income tax		(263)			390			(789)	1,281
Other Comprehensive Income (Loss), Net of Tax		712			(1,053)			2,135	(3,463)
Net Prior Service (Credit) Cost [Member]
Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	671			(932)			2,010	(3,210)
Reclassification from AOCI, Current Period, Tax		(180)			252			(542)	867
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		491			(680)			1,468	(2,343)
Net Actuarial Gain [Member]
Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	304			(511)			914	(1,534)
Reclassification from AOCI, Current Period, Tax		(83)			138			(247)	414
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		221			(373)			667	(1,120)
Cash Flow Hedges [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax								(1,532)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax								326
Other Comprehensive Income (Loss), before tax		157			(477)			(1,564)	(904)
Other Comprehensive Income (Loss), income tax		(36)			128			358	231
Other Comprehensive Income (Loss), Net of Tax		$ 121			$ (349)			$ (1,206)	$ (673)

[1] These accumulated other comprehensive income components are included in the computation of net periodic pension and postretirement plan cost (see Note 12) and are included in non-operating pension and postretirement benefit income in the Company’s Condensed Consolidated Statements of Operations.