Goodwill and Other Intangible Assets (Schedule of the Changes in the Carrying Amount of Goodwill) (Details) (USD $) In Thousands, unless otherwise specified			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Blaze [Member]	Dec. 31, 2012 Cotendo [Member]	Dec. 31, 2012 FastSoft [Member]	Dec. 31, 2012 Verivue [Member]
Goodwill [Roll Forward]
Beginning Balance	$ 731,325	$ 452,914
Purchase price allocation associated with acquisition			15,068	233,828	8,825	20,690
Ending balance	$ 731,325	$ 452,914