Schedule Of Reportable Segment And Reconciliation Of Segment Contribution Income To Income Before Income Taxes (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2015	Sep. 27, 2015	Jun. 28, 2015	Mar. 29, 2015	Dec. 31, 2014	Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Total net revenues		$ 360,863	$ 341,893	$ 288,782	$ 309,157	$ 353,182	$ 353,338	$ 337,604	$ 349,391	$ 1,300,695	$ 1,393,515	$ 1,369,633
Total segment contribution income										177,775	194,623	191,544
Corporate and unallocated costs										(54,501)	(53,581)	(51,629)
Amortization of intangible assets	[1]									(16,969)	(17,573)	(15,217)
Stock-based compensation expense										(16,825)	(20,014)	(17,462)
Restructuring and other charges										(6,398)	(2,209)	(5,335)
Acquisition-related expense	[2]									0	(8)	(940)
Losses on inventory commitments due to restructuring										(407)	0	(568)
Litigation reserves, net										2,682	1,011	(5,354)
Goodwill impairment charges										0	(74,196)	0
Intangibles Impairment charges										0	0	(2,000)
Interest income										295	253	400
Other income (expense), net										(88)	2,455	(457)
Income before income taxes										85,564	30,761	92,982
Retail [Member]
Segment Reporting Information [Line Items]
Total net revenues										614,367	508,100	509,924
Total segment contribution income										$ 85,231	$ 76,266	$ 73,418
Segment contribution margin (in percentage)										13.90%	15.00%	14.40%
Goodwill impairment charges										$ 0	$ 0
Commercial [Member]
Segment Reporting Information [Line Items]
Total net revenues										264,846	305,677	$ 311,261
Total segment contribution income										$ 53,393	$ 70,810	$ 66,506
Segment contribution margin (in percentage)										20.20%	23.20%	21.40%
Goodwill impairment charges										$ 0	$ 0
Service Provider [Member]
Segment Reporting Information [Line Items]
Total net revenues										421,482	579,738	$ 548,448
Total segment contribution income										$ 39,151	$ 47,547	$ 51,620
Segment contribution margin (in percentage)										9.30%	8.20%	9.40%
Goodwill impairment charges										$ 0	$ (74,196)

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

[2] These acquisition-related charges were expensed in the period incurred and reported in the Company's consolidated statements of operations within cost of revenues and operating expense.