Business Combination, Purchase Price Allocation (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012
Business Acquisition [Line Items]
Net tangible assets/(liabilities) acquired	$ (0.1)
Goodwill	59.0
Business Acquisition, Cost of Acquired Entity, Purchase Price	95.6
Business Acquisitions - 2012 [Member]
Business Acquisition [Line Items]
Acquired Finite and Indefinite Lived intangible Assets, Amount	36.7
Business Acquisition Acquired Entity BitGravity [Member] | Business Acquisitions - 2012 [Member]
Business Acquisition [Line Items]
Net tangible assets/(liabilities) acquired	0.1
Acquired Finite and Indefinite Lived intangible Assets, Amount	12.4
Goodwill	0.5
Business Acquisition, Cost of Acquired Entity, Purchase Price	13.0
Business Acquisition Acquired Entity Mykonos [Member] | Business Acquisitions - 2012 [Member]
Business Acquisition [Line Items]
Net tangible assets/(liabilities) acquired	(0.2)
Acquired Finite and Indefinite Lived intangible Assets, Amount	24.3
Goodwill	58.5
Business Acquisition, Cost of Acquired Entity, Purchase Price	$ 82.6