Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012
Income Statement [Abstract]
Net sales	$ 275,434	$ 290,601	$ 880,744	$ 969,319
Cost of sales	230,297	238,232	734,447	814,507
Gross margin	45,137	52,369	146,297	154,812
Selling, general and administrative expense	31,804	32,832	97,910	98,938
Research and development expense	3,190	3,019	9,901	9,310
Other—net	4,161	3,129	9,592	10,846
Operating profit	5,982	13,389	28,894	35,718
Interest expense—net	715	779	2,356	2,297
Income before income taxes	5,267	12,610	26,538	33,421
Income tax expense	144	4,496	5,721	11,260
Net income	$ 5,123	$ 8,114	$ 20,817	$ 22,161
Basic earnings per share:
Net income per share of common stock (in dollars per share)	$ 0.25	$ 0.40	$ 1.01	$ 1.08
Diluted earnings per share:
Net income per share of common stock (in dollars per share)	$ 0.24	$ 0.39	$ 1.00	$ 1.07
Cash dividends per share (in dollars per share)	$ 0.08	$ 0.075	$ 0.235	$ 0.15
Weighted-average number of shares of common stock outstanding:
Basic (in shares)	20,604	20,432	20,551	20,434
Diluted (in shares)	20,931	20,697	20,874	20,639