Consolidated Condensed Statements of Income (Unaudited) (USD $)	3 Months Ended		6 Months Ended
	Jul. 02, 2011	Jul. 03, 2010	Jul. 02, 2011	Jul. 03, 2010
Consolidated Condensed Statements of Income [Abstract]
Net sales	$ 122,029,000	$ 121,500,000	$ 230,370,000	$ 240,745,000
Cost of sales	78,045,000	75,563,000	147,564,000	153,039,000
Gross profit	43,984,000	45,937,000	82,806,000	87,706,000
Selling, general and administrative expenses	23,537,000	19,679,000	44,860,000	41,766,000
Operating income	20,447,000	26,258,000	37,946,000	45,940,000
Interest expense	(98,000)	(62,000)	(195,000)	(124,000)
Interest income	110,000	98,000	289,000	122,000
Income before income taxes	20,459,000	26,294,000	38,040,000	45,938,000
Provision for income taxes	6,301,000	8,478,000	11,892,000	14,295,000
Net income	$ 14,158,000	$ 17,816,000	$ 26,148,000	$ 31,643,000
Earnings per share:
Basic	$ 0.44	$ 0.53	$ 0.80	$ 0.94
Earnings per share - Diluted	$ 0.43	$ 0.53	$ 0.80	$ 0.94
Dividends declared per share	$ 0.19	$ 0.18	$ 0.38	$ 0.36