Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 29, 2012	Sep. 24, 2011	Sep. 29, 2012	Sep. 24, 2011
Numerator:
Net income from continuing operations	$ 19,756	$ 15,016	$ 51,156	$ 41,045
Net income (loss) from discontinued operations	586	(3,516)	4,506	(4,412)
Net income	$ 20,342	$ 11,500	$ 55,662	$ 36,633
Denominator:
Weighted average basic shares outstanding	36,240,000	35,933,000	36,089,000	35,842,000
Effect of stock-based compensation awards	382,000	485,000	400,000	523,000
Weighted average diluted shares outstanding	36,622,000	36,418,000	36,489,000	36,365,000
Basic:
Net income from continuing operations	$ 0.54	$ 0.42	$ 1.41	$ 1.15
Net income (loss) from discontinued operations	$ 0.02	$ (0.10)	$ 0.13	$ (0.13)
Net income	$ 0.56	$ 0.32	$ 1.54	$ 1.02
Diluted:
Net income from continuing operations	$ 0.54	$ 0.41	$ 1.40	$ 1.13
Net income (loss) from discontinued operations	$ 0.02	$ (0.09)	$ 0.13	$ (0.12)
Net income	$ 0.56	$ 0.32	$ 1.53	$ 1.01
Earnings Per Share (Textual) [Abstract]
Anti-dilutive options excluded from the calculation of earnings per share			50,000	30,000