Accumulated Other Comprehensive Income (Reclassifications) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenue	$ 790,125	$ 760,281	$ 2,373,782	$ 2,354,108
Interest expense, net	(28,704)	(26,588)	(84,325)	(89,377)
(Loss) income from continuing operations before taxes	(19,550)	45,188	18,761	149,788
Income tax (provision) benefit	24,895	2,468	13,351	(17,235)
Net (loss) income	(3,125)	80,277	17,913	191,842
Pension and Postretirement Benefit Plans	(254,092)	(241,350)	(757,228)	(759,469)
Reclassification out of Accumulated Other Comprehensive Loss | Cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenue	(98)	(38)	(23)	38
Cost of sales	54	52	99	(33)
Interest expense, net	0	(825)	0	(1,839)
(Loss) income from continuing operations before taxes	(44)	(811)	76	(1,834)
Income tax (provision) benefit	11	206	(19)	468
Net (loss) income	(33)	(605)	57	(1,366)
Reclassification out of Accumulated Other Comprehensive Loss | Available for sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net	146	(40)	42	150
Income tax (provision) benefit	(37)	10	(11)	(38)
Net (loss) income	109	(30)	31	112
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	(10,185)	(11,208)	(28,905)	(32,616)
Income tax (provision) benefit	2,633	2,399	7,406	7,766
Net (loss) income	(7,552)	(8,809)	(21,499)	(24,850)
Reclassification out of Accumulated Other Comprehensive Loss | Transition credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Pension and Postretirement Benefit Plans	2	2	5	5
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	(123)	(79)	(377)	(188)
Reclassification out of Accumulated Other Comprehensive Loss | Actuarial losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Pension and Postretirement Benefit Plans	(8,587)	(9,996)	(25,858)	(31,298)
Reclassification out of Accumulated Other Comprehensive Loss | Settlements
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Pension and Postretirement Benefit Plans	$ (1,477)	$ (1,135)	$ (2,675)	$ (1,135)