CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Net sales	$ 229,161	$ 397,550	$ 326,429
Cost of products sold	172,308	252,627	215,734
Gross profit	56,853	144,923	110,695
Costs and expenses:
General and administrative expenses	29,150	37,976	38,452
Selling and distribution expenses	23,863	27,475	22,761
Amortization of purchased intangible assets	1,449	1,544	2,944
Restructuring expenses, net and asset impairments	3,387	19,503	1,114
Anti-dumping duty penalties	0	0	8,000
Total costs and expenses	57,849	86,498	73,271
Operating (loss) income	(996)	58,425	37,424
Other expense:
Other expense, net	(233)	(169)	(1,202)
Interest expense, net	(731)	(1,554)	(1,615)
(Loss) income before income taxes	(1,960)	56,702	34,607
Income tax (benefit) provision	(548)	22,661	4,134
Net (loss) income	$ (1,412)	$ 34,041	$ 30,473
Net (loss) income per share
Basic (in dollars per share)	$ (0.10)	$ 2.29	$ 2.05
Diluted (in dollars per share)	$ (0.10)	$ 2.28	$ 2.04
Weighted-average shares outstanding:
Basic (in shares)	14,790,296	14,579,608	14,529,745
Diluted (in shares)	14,790,296	14,655,350	14,620,635
Dividends declared per common share (in dollars per share)	$ 0.125	$ 0.29	$ 0.08