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				6 Months Ended
	Jun. 29, 2014		Jun. 30, 2013		Jun. 29, 2014		Jun. 30, 2013
Segment Reporting Information [Line Items]
Total net revenues	$ 337,604		$ 357,719		$ 686,995		$ 651,118
Total segment contribution income	47,090		50,327		94,832		92,247
Corporate and unallocated costs	(13,128)		(13,558)		(26,884)		(26,024)
Amortization of intangible assets	(4,391)	[1]	(4,872)	[1]	(8,781)	[1]	(6,343)	[1]
Stock-based compensation expense	(4,934)		(4,391)		(10,064)		(7,981)
Restructuring and other charges	12		(1,587)		(830)		(1,557)
Acquisition-related expense	0		(214)		(8)		(924)
Impact to cost of sales from acquisition accounting adjustments to inventory	0		(568)		0		(568)
Litigation reserves, net	(68)		(3,555)		(185)		(3,603)
Interest income	49		95		106		244
Other expense, net	(227)		(548)		(335)		(474)
Income before income taxes	24,403		21,129		47,851		45,017
Retail [Member]
Segment Reporting Information [Line Items]
Total net revenues	110,663		117,395		228,895		243,717
Total segment contribution income	14,726		15,761		29,409		34,379
Segment contribution margin (in percentage)	13.30%		13.40%		12.80%		14.10%
Commercial [Member]
Segment Reporting Information [Line Items]
Total net revenues	75,447		88,446		154,310		159,297
Total segment contribution income	17,129		20,476		36,669		34,287
Segment contribution margin (in percentage)	22.70%		23.20%		23.80%		21.50%
Service Provider [Member]
Segment Reporting Information [Line Items]
Total net revenues	151,494		151,878		303,790		248,104
Total segment contribution income	$ 15,235		$ 14,090		$ 28,754		$ 23,581
Segment contribution margin (in percentage)	10.10%		9.30%		9.50%		9.50%

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