CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net sales	$ 326,429,000	$ 192,803,000	$ 158,575,000
Cost of products sold	215,734,000	133,412,000	119,895,000
Gross profit	110,695,000	59,391,000	38,680,000
Costs and expenses:
General and administrative expenses	38,452,000	27,135,000	22,115,000
Selling and distribution expenses	22,761,000	18,589,000	16,626,000
Amortization of purchased intangible assets	2,944,000	4,060,000	4,011,000
Restructuring expenses	1,114,000	4,283,000	1,202,000
Anti-dumping duty penalties	8,000,000	0	0
Goodwill impairment charge	0	17,584,000	0
Total costs and expenses	73,271,000	71,651,000	43,954,000
Operating income (loss)	37,424,000	(12,260,000)	(5,274,000)
Other income (expense):
Other income (expense), net	(1,202,000)	(1,376,000)	633,000
Interest expense, net	(1,615,000)	(1,648,000)	(1,067,000)
Income (loss) before income taxes	34,607,000	(15,284,000)	(5,708,000)
Income tax provision	4,134,000	3,569,000	797,000
Net income (loss)	$ 30,473,000	$ (18,853,000)	$ (6,505,000)
Net income (loss) per share:
Basic (in dollars per share)	$ 2.05	$ (1.31)	$ (0.46)
Diluted (in dollars per share)	$ 2.04	$ (1.31)	$ (0.46)
Weighted-average shares outstanding:
Basic (in shares)	14,529,745	14,346,851	14,126,108
Diluted (in shares)	14,620,635	14,346,851	14,126,108
Dividends declared per common share (in dollars per share)	$ 0.08	$ 0.08	$ 0.08