CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net sales	$ 218,025	$ 191,660
Cost of sales	175,969	152,153
Gross profit	42,056	39,507
Selling, product development and administrative expenses	33,006	25,471
Operating income	9,050	14,036
Interest expense	3,628	540
Other expense, net	399	315
Income before income taxes	5,023	13,181
Income tax expense	1,106	2,123
Loss from equity method investment	27	4
Net income	$ 3,890	$ 11,054
Earnings per share:
Basic (USD per share)	$ 0.23	$ 0.64
Diluted (USD per share)	$ 0.22	$ 0.64
Weighted average number of common shares outstanding:
Basic (shares)	17,254	17,164
Diluted (shares)	17,318	17,339