Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net sales	$ 1,185,424	$ 1,207,815	$ 1,139,447
Cost of sales	926,280	956,710	926,618
Gross margin	259,144	251,105	212,829
Selling, general, and administrative expense	147,164	153,489	144,280
Research and development expense	18,271	15,187	13,981
Goodwill impairment charges	11,560	0	0
Asset impairment charges	2,581	0	0
Restructuring expense	785	5,599	644
Other - net	11,783	15,334	13,893
Operating profit	67,000	61,496	40,031
Other non-operating expense-net	3,431	42,683	1,452
Interest expense - net	1,579	2,471	2,183
Income before income taxes	61,990	16,342	36,396
Income tax expense (benefit)	11,330	(4,504)	24,945
Net income	$ 50,660	$ 20,846	$ 11,451
Basic earnings per share:
Net income per share of common stock (in usd per share)	$ 2.49	$ 1.03	$ 0.57
Diluted earnings per share:
Net income per share of common stock (in usd per share)	$ 2.45	$ 1.01	$ 0.56
Weighted-average number of shares of common stock outstanding:
Basic	20,365	20,212	20,027
Diluted	20,655	20,613	20,415