Acquisition (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 01, 2012	Jul. 03, 2011	Jul. 01, 2012	Jul. 03, 2011
Summary of net sales and earnings before income taxes
Net sales	$ 154,294	$ 146,919	$ 301,263	$ 298,437
Loss before income taxes	4,513	5,035	6,810	11,628
Valpey-Fisher [Member]
Summary of net sales and earnings before income taxes
Net sales	3,955		6,946
Loss before income taxes	$ (272)		$ (111)