Segment Information (Revenues By Geographic Location) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 796,759	$ 781,560	$ 1,557,561	$ 1,532,379
Operating Segments [Member] | Enterprise and Service Provider Division [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	619,175	620,781	1,210,613	1,214,468
Operating Segments [Member] | Enterprise and Service Provider Division [Member] | Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	340,327	335,593	660,550	658,986
Operating Segments [Member] | Enterprise and Service Provider Division [Member] | EMEA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	206,908	207,069	410,181	407,697
Operating Segments [Member] | Enterprise and Service Provider Division [Member] | Asia-Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	71,940	78,119	139,882	147,785
Operating Segments [Member] | Mobility Apps [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	177,584	160,779	346,948	317,911
Operating Segments [Member] | Mobility Apps [Member] | Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	150,025	132,877	292,593	263,549
Operating Segments [Member] | Mobility Apps [Member] | EMEA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	22,142	22,193	43,363	43,373
Operating Segments [Member] | Mobility Apps [Member] | Asia-Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 5,417	$ 5,709	$ 10,992	$ 10,989