Segment Information (Revenues By Geographic Location) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 712,731	$ 641,422	$ 2,116,014	$ 1,846,127
Infrastructure [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	564,552	511,763	1,686,411	1,470,225
Infrastructure [Member] | Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	306,050	281,896	925,395	794,148
Infrastructure [Member] | EMEA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	188,220	164,149	553,637	488,196
Infrastructure [Member] | Asia-Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	70,282	65,718	207,379	187,881
SaaS [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	148,179	129,659	429,603	375,902
SaaS [Member] | Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	124,044	109,935	360,954	319,946
SaaS [Member] | EMEA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	18,522	15,941	53,266	45,974
SaaS [Member] | Asia-Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 5,613	$ 3,783	$ 15,383	$ 9,982