Goodwill and Purchased Intangible Assets, Finite Lived Intangible Assets by Class (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 5.6	$ 9.8	$ 17.6	$ 19.3
Acceleration of the end of life of certain intangible assets, finite-lived	0.0	0.0	5.6	0.0
Cost of Revenues [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	4.7	8.4	15.5	16.6
Sales and Marketing Expense [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	0.6	1.1	1.4	2.1
General and Administrative Expense [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	0.3	0.3	0.7	0.6
Operating expense [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 0.9	$ 1.4	$ 2.1	$ 2.7