Goodwill and Purchased Intangible Assets, Finite Lived Intangible Assets by Class (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 11.9	$ 9.5
Acceleration of the end of life of certain intangible assets, finite-lived	5.6
Cost of Revenues [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	10.8	8.2
Sales and Marketing Expense [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	0.8	1.0
General and Administrative Expense [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	0.3	0.3
Operating expense [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 1.1	$ 1.3