Net Income per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 29, 2012	Oct. 01, 2011	Sep. 29, 2012	Oct. 01, 2011
Earnings Per Share [Abstract]
Net income	$ 26,209	$ 17,236	$ 65,599	$ 45,108
Recnciliation of weighted-average shares outstanding:
Basic weighted-average shares outstanding (in shares)	55,444,000	55,214,000	55,601,000	54,966,000
Effect of dilutive securities:
Options (in shares)	1,121,000	777,000	1,085,000	804,000
Restricted shares (in shares)	421,000	504,000	516,000	536,000
Diluted weighted-average shares outstanding (in shares)	56,986,000	56,495,000	57,202,000	56,306,000
Net income per share - basic (in dollars per share)	$ 0.47	$ 0.31	$ 1.18	$ 0.82
Net income per share - diluted (in dollars per share)	$ 0.46	$ 0.31	$ 1.15	$ 0.80
Potentially Dilutive Stock Options [Member]
Stock options excluded from diluted net income (loss) per share calculation [Abstract]
Potentially dilutive stock options excluded from EPS calculation (in shares)	300,000	1,500,000	300,000	1,600,000