CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales	$ 837,398	$ 785,897	$ 698,437
Cost of sales	685,608	633,252	535,078
Gross profit	151,790	152,645	163,359
Selling, product development and administrative expenses	126,409	103,457	97,159
Impairment of goodwill and other long-lived assets	64,206	0	0
Operating (loss) income	(38,825)	49,188	66,200
Employee benefit plans settlement expenses	25,247	0	0
Interest expense	14,262	6,212	2,720
Other (income) expense, net	(1,257)	(289)	2,161
(Loss) income before income taxes	(77,077)	43,265	61,319
Income tax (benefit) expense	(6,416)	8,453	11,974
(Income) loss from equity method investment	(148)	(132)	28
Net (loss) income	$ (70,513)	$ 34,944	$ 49,317
(Loss) earnings per common share:
Basic (USD per share)	$ (4.08)	$ 2.03	$ 2.89
Diluted (USD per share)	$ (4.08)	$ 2.02	$ 2.85
Weighted average common shares outstanding (shares)	17,271	17,204	17,045
Weighted average common shares and equivalents outstanding (shares)	17,271	17,330	17,317