Changes in Accumulated Other Comprehensive Income (Loss) by Component - Amount Reclassified from Accumulated Other Comprehensive Income (Loss) (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]
Interest expense	$ (3,898)	$ (5,399)	$ (8,223)	$ (10,512)
Net sales	235,537	371,669	566,207	748,360
Income before income taxes	5,157	49,846	48,552	93,576
Tax benefit	(4,590)	(12,230)	(18,252)	(21,968)
Total reclassifications in the period	567	37,616	30,300	71,608
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications in the period	(3,147)	(2,156)	(6,328)	(4,047)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gains and Losses on Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(356)	139	(417)	281
Net sales	74	(252)	(449)	(589)
Income before income taxes	(282)	(113)	(866)	(308)
Tax benefit	95	22	137	63
Income from continuing operations	(187)	(91)	(729)	(245)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Pension and Other Postretirement Benefit Items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(3,866)	(2,634)	(7,315)	(4,911)
Tax benefit	906	569	1,716	1,109
Income from continuing operations	(2,960)	(2,065)	(5,599)	(3,802)
Amortization of prior-service credits, net	(80)	(105)	(167)	(214)
Amortization of actuarial losses	(3,302)	(2,282)	(6,664)	(4,450)
Curtailment loss	(484)	0	(484)	0
Settlement loss	$ 0	$ (247)	$ 0	$ (247)