Condensed Consolidated Statements of Earnings (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 01, 2012	Jul. 03, 2011	Jul. 01, 2012	Jul. 03, 2011
Condensed Consolidated Statements of Earnings [Abstract]
Net sales	$ 154,294	$ 146,919	$ 301,263	$ 298,437
Costs and expenses:
Cost of goods sold	128,356	119,051	253,276	241,409
Insurance recovery for business interruption - casualties	(7,423)		(11,050)
Selling, general and administrative expenses	19,378	18,057	38,782	36,429
Research and development expenses	5,131	4,590	11,240	9,619
Insurance recovery for property damage - casualties			(1,769)
Restructuring and impairment charges - Note M	3,139	694	3,139	694
Operating earnings	5,713	4,527	7,645	10,286
Other (expense)/income:
Interest expense	(626)	(511)	(1,285)	(1,003)
Interest income	467	276	916	472
Other	(1,041)	743	(466)	1,873
Total other income/(expense)	(1,200)	508	(835)	1,342
Earnings before income taxes	4,513	5,035	6,810	11,628
Income tax expense	1,212	903	1,226	2,380
Net earnings	$ 3,301	$ 4,132	$ 5,584	$ 9,248
Net earnings per share - Note J
Basic	$ 0.10	$ 0.12	$ 0.16	$ 0.27
Diluted	$ 0.10	$ 0.12	$ 0.16	$ 0.26
Cash dividends declared per share	$ 0.035	$ 0.03	$ 0.07	$ 0.06
Average common shares outstanding:
Basic	34,022	34,375	34,064	34,334
Diluted	34,574	35,025	34,647	35,050