Earnings Per Share (Details) (USD $)	3 Months Ended		6 Months Ended
	Jul. 02, 2011	Jul. 03, 2010	Jul. 02, 2011	Jul. 03, 2010
Earnings per share - Basic
Net income	$ 14,158,000	$ 17,816,000	$ 26,148,000	$ 31,643,000
Less: Net earnings allocated to participating securities - Basic	(141,000)	(187,000)	(270,000)	(339,000)
Income available to common shareholders - Basic	14,017,000	17,629,000	25,878,000	31,304,000
Weighted average common shares outstanding - Basic	32,205,000	33,119,000	32,406,000	33,225,000
Earnings per share - Basic	$ 0.44	$ 0.53	$ 0.80	$ 0.94
Earnings per share - Diluted
Net income	14,158,000	17,816,000	26,148,000	31,643,000
Less: Net earnings allocated to participating securities - Diluted	(141,000)	(187,000)	(270,000)	(339,000)
Income available to common shareholders - Diluted	$ 14,017,000	$ 17,629,000	$ 25,878,000	$ 31,304,000
Weighted average common shares outstanding - Diluted
Weighted average common shares outstanding - Basic	32,205,000	33,119,000	32,406,000	33,225,000
Potential dilutive shares resulting from stock options	28,000	28,000	28,000	28,000
Weighted average common shares outstanding - Diluted	32,233,000	33,147,000	32,434,000	33,253,000
Earnings per share - Diluted	$ 0.43	$ 0.53	$ 0.80	$ 0.94
Shares excluded from diluted earnings per share computation
Shares excluded	420,500	385,500	403,000	385,500