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				9 Months Ended
	Sep. 29, 2013		Sep. 30, 2012		Sep. 29, 2013		Sep. 30, 2012
Segment Reporting Information [Line Items]
Total net revenues	$ 361,895		$ 315,210		$ 1,013,013		$ 961,485
Total segment contribution income	48,694		49,040		140,941		148,684
Corporate and unallocated costs	(12,800)		(12,866)		(38,824)		(36,430)
Amortization of intangible assets	(4,439)	[1]	(1,354)	[1]	(10,782)	[1]	(3,317)	[1]
Stock-based compensation expense	(4,511)		(4,019)		(12,492)		(10,806)
Restructuring and other charges	(400)		0		(1,957)		0
Acquisition-related expense	0		0		(924)		0
Impact to cost of sales from acquisition accounting adjustments to inventory	0		0		(568)		0
Litigation reserves, net	(305)		(269)		(3,908)		(420)
Impairment charges	(2,000)		0		(2,000)		0
Interest income	71		109		315		344
Other income, net	511		3,070		37		2,823
Income before income taxes	24,821		33,711		69,838		100,878
Retail [Member]
Segment Reporting Information [Line Items]
Total net revenues	130,301		123,457		374,018		366,258
Total segment contribution income	19,317		17,759		53,696		62,590
Segment contribution margin (in percentage)	14.80%		14.40%		14.40%		17.10%
Commercial [Member]
Segment Reporting Information [Line Items]
Total net revenues	76,957		79,240		236,254		234,498
Total segment contribution income	16,903		19,998		51,190		52,272
Segment contribution margin (in percentage)	22.00%		25.20%		21.70%		22.30%
Service Provider [Member]
Segment Reporting Information [Line Items]
Total net revenues	154,637		112,513		402,741		360,729
Total segment contribution income	$ 12,474		$ 11,283		$ 36,055		$ 33,822
Segment contribution margin (in percentage)	8.10%		10.00%		9.00%		9.40%

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