Investments in Affiliates Investment Interest Joint Venture (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended				1 Months Ended
	Sep. 30, 2011 years payment	Sep. 30, 2011 STARS [Member] years	Mar. 31, 2011 STARS [Member]	May 30, 2011 RP Data [Member]	Oct. 31, 2011 Veros [Member]	Sep. 30, 2011 Veros [Member]
Equity Method Investment, Ownership Percentage			50.10%	40.20%
Equity Method Investment, Aggregate Cost			$ 35.0
Payments to Acquire Interest in Joint Venture		20.0
Joint Venture Deferred Purchase Price		15.0
Number Of Joint Venture Interest Acquisition Deferred Installment Payment	3
Joint Venture Deferred Payment Installment Amount		5.0
Joint Venture Deferred Payment Discounted Amount		12.7
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity			30.8
Acquired Indefinite-lived Intangible Asset, Amount			9.7
Acquired Finite-lived Intangible Asset, Amount			21.1
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life		9.3
Business Acquisition, Preexisting Relationship, Gain (Loss) Recognized				58.9
Asset Impairment Charges						0.8
Proceeds from Divestiture of Interest in Joint Venture					$ 8.0