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, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (4,475)	$ (3,898)	$ (8,416)	$ (8,223)
Net sales	321,158	235,537	622,787	566,207
Income before income taxes	32,796	5,157	59,773	48,552
Tax benefit	(8,305)	(4,590)	(15,900)	(18,252)
Net income	24,491	567	43,873	30,300
Amount Reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	(3,462)	(3,147)	(6,833)	(6,328)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Gains and losses on cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(460)	(356)	(909)	(417)
Net sales	171	74	298	(449)
Income before income taxes	(289)	(282)	(611)	(866)
Tax benefit	73	95	158	137
Net income	(216)	(187)	(453)	(729)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Amortization of prior service costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(88)	(80)	(180)	(167)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Amortization of actuarial losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(4,150)	(3,302)	(8,146)	(6,664)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Pension and Other Postretirement Benefit Items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(4,238)	(3,866)	(8,326)	(7,315)
Curtailment loss	0	(484)	0	(484)
Tax benefit	992	906	1,946	1,716
Net income	$ (3,246)	$ (2,960)	$ (6,380)	$ (5,599)