Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 25, 2011	Jun. 30, 2012	Jun. 25, 2011
Numerator:
Net income from continuing operations	$ 16,106	$ 12,881	$ 31,400	$ 26,029
Net income (loss) from discontinued operations	3,636	(134)	3,920	(896)
Net income	$ 19,742	$ 12,747	$ 35,320	$ 25,133
Denominator:
Weighted average basic shares outstanding	36,058,000	35,850,000	36,014,000	35,796,000
Effect of stock-based compensation awards	578,000	605,000	559,000	610,000
Weighted average diluted shares outstanding	36,636,000	36,455,000	36,573,000	36,406,000
Basic:
Net income from continuing operations	$ 0.45	$ 0.36	$ 0.87	$ 0.73
Net income (loss) from discontinued operations	$ 0.10	$ 0.00	$ 0.11	$ (0.03)
Net income	$ 0.55	$ 0.36	$ 0.98	$ 0.70
Diluted:
Net income from continuing operations	$ 0.44	$ 0.35	$ 0.86	$ 0.71
Net income (loss) from discontinued operations	$ 0.10	$ 0.00	$ 0.11	$ (0.02)
Net income	$ 0.54	$ 0.35	$ 0.97	$ 0.69
Earnings Per Share (Textual) [Abstract]
Anti-dilutive options excluded from the calculation of earnings per share			50,000	30,000