Accumulated Other Comprehensive Loss (Reclassifications) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenue	$ 796,268	$ 795,084
Interest expense, net	(25,883)	(27,602)
(Loss) income from continuing operations before taxes	(228,577)	5,277
Income tax provision (benefit)	10,030	(7,820)
Net loss	(208,483)	(2,659)
Pension and Postretirement Benefit Plans	(248,633)	(261,669)
Reclassification out of Accumulated Other Comprehensive Loss | Cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenue	61	111
Cost of sales	10	16
(Loss) income from continuing operations before taxes	71	127
Income tax provision (benefit)	17	32
Net loss	54	95
Reclassification out of Accumulated Other Comprehensive Loss | Available for sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net	284	(23)
Income tax provision (benefit)	71	(6)
Net loss	213	(17)
Reclassification out of Accumulated Other Comprehensive Loss | Pension and postretirement benefit plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
(Loss) income from continuing operations before taxes	(11,520)	(9,285)
Income tax provision (benefit)	(2,650)	(2,649)
Net loss	(8,870)	(6,636)
Reclassification out of Accumulated Other Comprehensive Loss | Transition credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Pension and Postretirement Benefit Plans	1	2
Reclassification out of Accumulated Other Comprehensive Loss | Prior service costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Pension and Postretirement Benefit Plans	(139)	(128)
Reclassification out of Accumulated Other Comprehensive Loss | Actuarial losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Pension and Postretirement Benefit Plans	(10,993)	(9,159)
Reclassification out of Accumulated Other Comprehensive Loss | Settlements
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Pension and Postretirement Benefit Plans	$ (389)	$ 0