Goodwill and Other Intangible Assets Narrative (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Feb. 07, 2012 Blaze Acquisition [Member]	Mar. 06, 2012 Cotendo Acquisition [Member]	Sep. 13, 2012 FastSoft [Member]	Dec. 04, 2012 Verivue [Member]
Goodwill [Line Items]
Business acquisition purchase price allocation for goodwill					$ 15,100,000	$ 233,800,000	$ 8,900,000	$ 20,700,000
Business acquisition purchase price allocation for intangible assets					5,100,000	43,800,000	3,700,000	7,500,000
Amortization of acquired intangible assets	5,734,000	5,463,000	11,794,000	10,230,000
Future amortization expense to be recognized in remainder of current year	9,600,000		9,600,000
Future amortization expense 2014	18,800,000		18,800,000
Future amortization expense 2015	16,200,000		16,200,000
Future amortization expense 2016	11,400,000		11,400,000
Future amortization expense 2017	$ 7,600,000		$ 7,600,000