Accumulated Other Comprehensive Loss (AOCL) (Reclassifications) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenue	$ 837,492	$ 788,573	$ 1,633,760	$ 1,583,657
Income (loss) from continuing operations before taxes	16,719	33,034	(211,858)	38,311
Income tax provision (benefit)	(17,016)	(3,724)	(6,986)	(11,544)
Net (loss) income	(3,329)	23,697	(211,812)	21,038
Interest expense, net	(26,446)	(28,019)	(52,329)	(55,621)
Pension and Postretirement Benefit Plans	(233,631)	(241,467)	(482,264)	(503,136)
Reclassification out of Accumulated Other Comprehensive Loss | Cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenue	(64)	(36)	(3)	75
Cost of sales	32	29	42	45
Income (loss) from continuing operations before taxes	(32)	(7)	39	120
Income tax provision (benefit)	(8)	(1)	10	31
Net (loss) income	(24)	(6)	29	89
Reclassification out of Accumulated Other Comprehensive Loss | Available for sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax provision (benefit)	805	(21)	876	(27)
Net (loss) income	2,428	(60)	2,641	(77)
Interest expense, net	3,233	(81)	3,517	(104)
Reclassification out of Accumulated Other Comprehensive Loss | Pension and postretirement benefit plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) from continuing operations before taxes	(14,879)	(9,435)	(26,399)	(18,720)
Income tax provision (benefit)	(3,502)	(2,124)	(6,152)	(4,773)
Net (loss) income	(11,377)	(7,311)	(20,247)	(13,947)
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	1	2	3
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	(138)	(126)	(277)	(254)
Reclassification out of Accumulated Other Comprehensive Loss | Actuarial losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Pension and Postretirement Benefit Plans	(10,940)	(8,112)	(21,933)	(17,271)
Reclassification out of Accumulated Other Comprehensive Loss | Settlements
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Pension and Postretirement Benefit Plans	$ (3,802)	$ (1,198)	$ (4,191)	$ (1,198)