Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 26, 2020	Jun. 28, 2019	Jun. 26, 2020	Jun. 28, 2019
Income Statement [Abstract]
Net sales	$ 271,468	$ 297,843	$ 549,414	$ 599,284
Cost of sales	223,378	228,249	455,749	460,378
Gross margin	48,090	69,594	93,665	138,906
Selling, general, and administrative expense	32,852	39,891	63,596	79,955
Research and development expense	4,502	4,062	8,687	7,802
Goodwill impairment charges	0	0	9,053	0
Held for sale impairment charges	0	0	1,713	0
Restructuring charges	2,387	0	4,551	0
Other - net	(357)	2,891	1,922	7,012
Operating profit	8,706	22,750	4,143	44,137
Other non-operating (income) expense - net	(851)	3,112	(1,795)	3,357
Interest Expense-net	1,259	500	1,505	966
Income before income taxes	8,298	19,138	4,433	39,814
Income tax expense	1,620	3,598	858	7,368
Net income	$ 6,678	$ 15,540	$ 3,575	$ 32,446
Basic earnings per share:
Net income per share of common stock (in dollars per share)	$ 0.33	$ 0.76	$ 0.18	$ 1.60
Diluted earnings per share:
Net income per share of common stock (in dollars per share)	$ 0.32	$ 0.75	$ 0.17	$ 1.57
Weighted-average number of shares of common stock outstanding:
Basic (in shares)	20,317	20,383	20,350	20,326
Diluted (in shares)	20,554	20,666	20,587	20,635