Segment Information, Operations By Geographic Area And Customer Concentration (Schedule Of Reportable Segment And Reconciliation Of Segment Contribution Income To Income Before Income Taxes) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2014		Mar. 31, 2013
Segment Reporting Information [Line Items]
Total net revenues	$ 349,391		$ 293,399
Total segment contribution income	47,742		41,920
Corporate and unallocated costs	(13,756)		(12,466)
Amortization of intangible assets	(4,390)	[1]	(1,471)	[1]
Stock-based compensation expense	(5,130)		(3,590)
Restructuring and other charges	(842)		30
Acquisition-related expense	(8)		(710)
Litigation reserves, net	(117)		(48)
Interest income	57		149
Other (expense) income, net	(108)		74
Income before income taxes	23,448		23,888
Retail [Member]
Segment Reporting Information [Line Items]
Total net revenues	118,232		126,322
Total segment contribution income	14,683		18,618
Segment contribution margin (in percentage)	12.40%		14.70%
Commercial [Member]
Segment Reporting Information [Line Items]
Total net revenues	78,863		70,851
Total segment contribution income	19,540		13,811
Segment contribution margin (in percentage)	24.80%		19.50%
Service Provider [Member]
Segment Reporting Information [Line Items]
Total net revenues	152,296		96,226
Total segment contribution income	$ 13,519		$ 9,491
Segment contribution margin (in percentage)	8.90%		9.90%

[1] Amount excludes amortization expense related to patents within purchased intangible assets in costs of revenues.