Goodwill and Other Intangible Assets (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Mar. 31, 2012 Blaze Acquisition [Member]	Feb. 07, 2012 Blaze Acquisition [Member]	Mar. 31, 2012 Cotendo Acquisition [Member]	Mar. 06, 2012 Cotendo Acquisition [Member]	Sep. 30, 2012 FastSoft [Member]	Sep. 13, 2012 FastSoft [Member]
Goodwill [Line Items]
Business acquisition purchase price allocation for goodwill					$ 15,068,000	$ 15,100,000	$ 241,646,000	$ 241,386,000	$ 12,233,000	$ 12,200,000
Identifiable intangible assets						5,100,000		43,800,000		3,700,000
Amortization of other intangible assets	5,381,000	4,185,000	15,611,000	12,754,000
Future amortization expense recognized in remainder of current year			5,400,000
Future amortization expense 2013			23,600,000
Future amortization expense 2014			18,200,000
Future amortization expense 2015			14,500,000
Future amortization expense 2016			$ 10,100,000