Business Acquisitions and Divestitures Narrative (Details) (USD $)	9 Months Ended				3 Months Ended	0 Months Ended	3 Months Ended	0 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012		Mar. 31, 2013 ADS Divesiture [Member]	Nov. 30, 2012 Strategic Network Acquisition [Member]	Sep. 30, 2013 Strategic Network Acquisition [Member]	Dec. 04, 2012 Verivue [Member]	Sep. 13, 2012 FastSoft [Member]	Mar. 06, 2012 Cotendo Acquisition [Member]	Feb. 07, 2012 Blaze Acquisition [Member]	Sep. 30, 2013 Purchase Price Allocation Adjustments [Member] Verivue [Member]	Sep. 30, 2013 Purchase Price Allocation Adjustments [Member] FastSoft [Member]
Business Acquisition [Line Items]
Total purchase consideration						$ 55,000,000.0		$ 30,900,000	$ 14,400,000	$ 278,900,000	$ 19,300,000
Consideration paid							27,500,000
Allocated to goodwill	751,271,000		723,701,000	[1]		29,500,000		14,900,000	7,100,000	233,800,000	15,100,000	5,800,000	1,800,000
Allocated to intangible assets						16,100,000		7,500,000	3,700,000	43,800,000	5,100,000
Weighted average usefule life						9 years 9 months 18 days		6 years 4 months 24 days	9 years	7 years 1 month 6 days	5 years 3 months 18 days
Goodwill, expected tax deductible amount						29,500,000		3,000,000	1,700,000	44,400,000	13,500,000
Contingent consideration liability								1,200,000
Convertible note receivable received for divestiture of a business	$ 18,882,000	$ 0			$ 25,000,000

[1] Balance as of January 1, 2013 has been revised to reflect purchase accounting measurement period adjustments (Note 6).