Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Oct. 02, 2015	Sep. 30, 2016	Oct. 02, 2015
Income Statement [Abstract]
Net sales	$ 249,619	$ 244,354	$ 734,906	$ 811,233
Cost of sales	198,864	200,351	595,488	663,548
Gross margin	50,755	44,003	139,418	147,685
Selling, general, and administrative expense	34,177	29,051	97,101	101,578
Research and development expense	3,237	2,501	9,860	9,435
Other net	3,190	1,590	8,997	(532)
Operating profit	10,151	10,861	23,460	37,204
Interest expense—net	490	586	1,417	1,893
Income before income taxes	9,661	10,275	22,043	35,311
Income tax expense	1,616	2,883	3,081	9,868
Net income	$ 8,045	$ 7,392	$ 18,962	$ 25,443
Basic earnings per share:
Net income per share of common stock (in dollars per share)	$ 0.40	$ 0.37	$ 0.95	$ 1.26
Diluted earnings per share:
Net income per share of common stock (in dollars per share)	0.40	0.36	0.94	1.24
Cash dividends per share (in dollars per share)	$ 0.095	$ 0.090	$ 0.280	$ 0.265
Weighted-average number of shares of common stock outstanding:
Basic (in shares)	19,957	20,087	19,996	20,128
Diluted (in shares)	20,192	20,383	20,209	20,458