Net Income Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 02, 2012	Sep. 27, 2011	Oct. 02, 2012	Sep. 27, 2011
Net Income Per Share
Shares of restricted stock issued to employees, unvested	1,200,000	700,000	1,200,000	700,000
Net income per share, basic and diluted
Net income	$ 27,163	$ 20,574	$ 76,284	$ 65,778
Basic weighted average shares outstanding	52,958,000	55,661,000	53,264,000	57,136,000
Dilutive effect of equity awards (in shares)	2,168,000	1,778,000	2,007,000	1,972,000
Diluted weighted average shares outstanding	55,126,000	57,439,000	55,271,000	59,108,000
Basic net income per share (in dollars per share)	$ 0.51	$ 0.37	$ 1.43	$ 1.15
Diluted net income per share (in dollars per share)	$ 0.49	$ 0.36	$ 1.38	$ 1.11
Shares of common stock not included in the diluted calculation due to their anti-dilutive effect	1,900,000	3,300,000	2,800,000	2,700,000