Changes in Accumulated Other Comprehensive Income (Loss) by Component - Amount Reclassified from Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (3,701)	$ (5,344)	$ (11,924)	$ (15,856)
Net sales	269,059	372,587	835,266	1,120,947
Income before income taxes	27,495	59,717	76,048	153,293
Tax benefit	(12,137)	(13,948)	(30,390)	(35,916)
Total reclassifications in the period	15,358	45,769	45,658	117,377
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications in the period	(2,928)	(1,958)	(9,258)	(6,006)
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	(449)	86	(866)	367
Net sales	237	(199)	(213)	(788)
Income before income taxes	(212)	(113)	(1,079)	(421)
Tax benefit	85	19	221	81
Income from continuing operations	(127)	(94)	(858)	(340)
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	(3,645)	(2,418)	(10,960)	(7,329)
Tax benefit	844	554	2,560	1,663
Income from continuing operations	(2,801)	(1,864)	(8,400)	(5,666)
Amortization of prior-service credits, net	(134)	(107)	(301)	(321)
Amortization of actuarial losses	(3,511)	(2,218)	(10,175)	(6,668)
Curtailment loss			(484)	0
Settlement loss	$ 0	$ (93)	$ 0	$ (340)