CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Net sales	$ 220,811	$ 186,413	$ 438,836	$ 378,073
Cost of sales	175,536	150,286	351,505	302,439
Gross profit	45,275	36,127	87,331	75,634
Selling, product development and administrative expenses	32,096	23,878	65,102	49,349
Operating income	13,179	12,249	22,229	26,285
Pension plan settlement expense	25,515	0	25,515	0
Interest expense	3,731	572	7,359	1,112
Other income, net	(873)	(368)	(474)	(53)
(Loss) income before income taxes	(15,194)	12,045	(10,171)	25,226
Income tax (benefit) expense	(8,199)	1,655	(7,093)	3,778
Income from equity method investment	(49)	(60)	(22)	(56)
Net (loss) income	$ (6,946)	$ 10,450	$ (3,056)	$ 21,504
Earnings (loss) per share:
Basic (USD per share)	$ (0.40)	$ 0.61	$ (0.18)	$ 1.25
Diluted (USD per share)	$ (0.40)	$ 0.60	$ (0.18)	$ 1.24
Weighted average number of common shares outstanding:
Basic (shares)	17,267	17,196	17,260	17,178
Diluted (shares)	17,267	17,335	17,260	17,334