Net Income Per Share (Schedule Of Net Income Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Oct. 02, 2011	Sep. 30, 2012	Oct. 02, 2011
Earnings Per Share [Abstract]
Net income	$ 23,791	$ 26,747	$ 70,460	$ 68,533
Weighted average shares outstanding: Basic (in shares)	38,162,000	37,483,000	37,978,000	36,967,000
Weighted average shares outstanding: Dilutive potential common shares (in shares)	640,000	597,000	704,000	845,000
Weighted average shares outstanding: Total diluted shares (in shares)	38,802,000	38,080,000	38,682,000	37,812,000
Basic net income per share (in dollars per share)	$ 0.62	$ 0.71	$ 1.86	$ 1.85
Diluted net income per share (in dollars per share)	$ 0.61	$ 0.70	$ 1.82	$ 1.81
Anti-dilutive common stock options (in shares)	2,600,000	1,900,000	2,700,000	1,900,000