Accumulated Other Comprehensive Income (Reclassifications) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenue	$ 868,402	$ 896,583
Interest expense, net	(27,602)	(32,014)
Income from continuing operations before taxes	6,872	70,278
Income tax benefit	(8,301)	(18,795)
Net (loss) income	(2,659)	59,970
Pension and Postretirement Benefit Plans	(300,982)	(302,810)
Reclassification out of Accumulated Other Comprehensive Loss | Cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenue	111	(3)
Cost of sales	16	(84)
Interest expense, net	0	(507)
Income from continuing operations before taxes	127	(594)
Income tax benefit	32	(151)
Net (loss) income	95	(443)
Reclassification out of Accumulated Other Comprehensive Loss | Available for sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net	(23)	(24)
Income tax benefit	(6)	(6)
Net (loss) income	(17)	(18)
Reclassification out of Accumulated Other Comprehensive Loss | Pension and postretirement benefit plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations before taxes	(9,285)	(10,975)
Income tax benefit	(2,649)	(2,803)
Net (loss) income	(6,636)	(8,172)
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
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	(128)	(55)
Reclassification out of Accumulated Other Comprehensive Loss | Actuarial losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Pension and Postretirement Benefit Plans	$ (9,159)	$ (10,922)