Net Income Per Share (Schedule Of Net Income Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2014	Jun. 30, 2013	Jun. 29, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]
Net income	$ 14,705	$ 13,985	$ 29,116	$ 29,328
Weighted average shares outstanding: Basic (in shares)	36,139,000	38,539,000	36,381,000	38,493,000
Weighted average shares outstanding: Dilutive potential common shares (in shares)	669,000	535,000	671,000	584,000
Weighted average shares outstanding: Total diluted shares (in shares)	36,808,000	39,074,000	37,052,000	39,077,000
Basic net income per share (in dollars per share)	$ 0.41	$ 0.36	$ 0.80	$ 0.76
Diluted net income per share (in dollars per share)	$ 0.40	$ 0.36	$ 0.79	$ 0.75
Anti-dilutive common stock options (in shares)	2,500,000	2,900,000	2,500,000	2,800,000