Net Income Per Share (Schedule Of Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2015	Sep. 28, 2014	Sep. 27, 2015	Sep. 28, 2014
Earnings Per Share [Abstract]
Net income	$ 15,099	$ 20,025	$ 26,777	$ 49,141
Weighted average shares outstanding: Basic (in shares)	31,979	35,643	33,473	36,133
Potentially dilutive common share equivalent (in shares)	356	607	529	673
Weighted average common shares outstanding: dilutive (in shares)	32,335	36,250	34,002	36,806
Basic net income per share (in dollars per share)	$ 0.47	$ 0.56	$ 0.80	$ 1.36
Diluted net income per share (in dollars per share)	$ 0.47	$ 0.55	$ 0.79	$ 1.34
Anti-dilutive employee stock-based awards, excluded (in shares)	2,768	2,774	2,486	2,608