Segment Information (Net Revenues And Profit By Segment) (Details) $ in Thousands		3 Months Ended						9 Months Ended
		Sep. 30, 2015 USD ($)		Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2014 USD ($)		Sep. 30, 2015 USD ($) segment		Sep. 30, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment								2
Net revenues		$ 813,270				$ 758,994		$ 2,370,831		$ 2,291,373
Segment profit		63,798				58,597		237,679		184,903
Restructuring		(13,766)				(3,124)		(62,251)		(17,285)
Stock-based compensation		(38,671)				(42,449)		(103,674)		(128,440)
Consolidated income before income taxes		53,358				48,222		199,682		168,005
Operating Segments [Member] | Enterprise and Service Provider Division [Member]
Segment Reporting Information [Line Items]
Net revenues		622,513				593,741		1,833,126		1,808,209
Segment profit		190,372	[1]	$ 174,900	$ 132,100	131,409	[1]	497,351	[1]	394,536	[1]
Operating Segments [Member] | Mobility Apps [Member]
Segment Reporting Information [Line Items]
Net revenues		190,757				165,253		537,705		483,164
Segment profit		22,901	[1]	$ 22,300	$ 15,000	27,402	[1]	60,202	[1]	92,333	[1]
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Amortization and impairment of intangible assets	[2]	(97,038)				(33,915)		(154,931)		(135,515)
Patent litigation charge	[2]	0				(20,727)		0		(20,727)
Other	[2]	0				0		982		0
Restructuring	[2]	(13,766)				(3,124)		(62,251)		(17,285)
Net interest and other expense, net	[2]	(10,440)				(10,374)		(37,997)		(16,897)
Stock-based compensation	[2]	$ (38,671)				$ (42,449)		$ (103,674)		$ (128,440)

[1] The Company revised its methodology for allocating certain corporate costs within General and administrative expenses to more closely align these costs to the employees directly utilizing the related services within each of its reporting segments, thereby impacting Segment profit for the nine months ended September 30, 2015. Accordingly, the adjusted Segment profit for the Enterprise and Service Provider and Mobility Apps segments is $132.1 million and $15.0 million, respectively for the three months ended March 31, 2015 and $174.9 million and $22.3 million, respectively for the three months ended June 30, 2015. This change in presentation does not affect the Company's consolidated financial position, results from operations or cash flows.

[2] Represents expenses presented to management on a consolidated basis only and not allocated to the operating segments.