Condensed Consolidated Statements of Earnings - Unaudited (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Apr. 01, 2012
Condensed Consolidated Statements of Earnings [Abstract]
Net sales	$ 149,512	$ 146,969
Costs and expenses:
Cost of goods sold	118,332	124,920
Insurance recovery for business interruption - casualties		(3,627)
Selling, general, and administrative expenses	21,407	19,404
Research and development expenses	6,252	6,109
Insurance recovery for property damage - casualties		(1,769)
Restructuring and impairment charge - Note M	559
Operating earnings	2,962	1,932
Other (expense)/income:
Interest expense	(915)	(659)
Interest income	413	449
Other	298	575
Total other (expense)/income	(204)	365
Earnings before income taxes	2,758	2,297
Income tax (benefit)/expense	(810)	14
Net earnings	$ 3,568	$ 2,283
Net earnings per share - Note J
Basic	$ 0.11	$ 0.07
Diluted	$ 0.10	$ 0.07
Cash dividends declared per share	$ 0.035	$ 0.035
Average common shares outstanding:
Basic	33,523	34,106
Diluted	34,176	34,718