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
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Earnings Per Share [Abstract]
Net income	$ 20,794	$ 21,119	$ 51,370	$ 53,742
Weighted average shares outstanding: Basic (in shares)	31,704	32,913	32,335	32,688
Potentially dilutive common share equivalent (in shares)	689	1,000	934	936
Weighted average common shares outstanding: dilutive (in shares)	32,393	33,913	33,269	33,624
Basic net income per share (in dollars per share)	$ 0.66	$ 0.64	$ 1.59	$ 1.64
Diluted net income per share (in dollars per share)	$ 0.64	$ 0.62	$ 1.54	$ 1.60
Anti-dilutive employee stock-based awards, excluded (in shares)	975	0	431	235