Acquisitions (Details)	9 Months Ended	1 Months Ended	9 Months Ended			1 Months Ended		3 Months Ended				3 Months Ended		3 Months Ended		1 Months Ended		1 Months Ended
	Sep. 30, 2011 USD ($)	May 31, 2011 RP Data [Member] Data and Analytics [Member] USD ($)	Sep. 30, 2011 RP Data [Member] Data and Analytics [Member] USD ($)	Mar. 31, 2011 Dorado Network Systems [Member] USD ($)	Dec. 31, 2010 Dorado Network Systems [Member] USD ($)	Jan. 31, 2011 Dorado Network Systems [Member] Customer Lists [Member] years	Mar. 31, 2011 Dorado Network Systems [Member] Customer Lists [Member] USD ($)	Mar. 31, 2011 Dorado Network Systems [Member] Trade Names [Member] USD ($) years	Jun. 30, 2011 RP Data [Member] USD ($)	May 30, 2011 RP Data [Member] USD ($)	May 30, 2011 RP Data [Member] AUD	Sep. 30, 2011 RP Data [Member] Customer Lists [Member] years	May 30, 2011 RP Data [Member] Customer Lists [Member] USD ($)	Sep. 30, 2011 RP Data [Member] Trade Names [Member] years	May 30, 2011 RP Data [Member] Trade Names [Member] USD ($)	Sep. 30, 2011 Tarasoft [Member] USD ($)	Sep. 30, 2011 Tarasoft [Member] CAD	Sep. 30, 2011 Tarasoft [Member] Customer Lists [Member] USD ($) years	Sep. 30, 2011 Tarasoft [Member] Trade Names [Member] USD ($) years	Sep. 30, 2011 Tarasoft [Member] Noncompete Agreements [Member] USD ($) years
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Cash Paid				$ 31,600,000						$ 157,200,000	147,200,000					$ 30,300,000	30,000,000
Equity Method Investment, Ownership Percentage					39.00%					40.20%	40.20%
Business Acquisition, Preexisting Relationship, Gain (Loss) Recognized					(14,500,000)					58,900,000
Business Acquisition, Purchase Price Allocation, Goodwill Amount				18,900,000
Business Acquisition Purchase Price Allocation Developed Software							20,400,000	3,200,000					46,700,000		11,700,000			2,700,000	400,000	200,000
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life						12		5				8		10				10	10	5
Goodwill, Acquired During Period	195,129,000	162,700,000	176,231,000													13,500,000
Notional Amount of Foreign Currency Derivatives											180,300,000
Business Acquisition Recognized Marked To Market Gain									$ 1,800,000