Acquisitions (Narrative) (Detail) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2012 USD ($)	Dec. 31, 2011 USD ($)	Sep. 30, 2012 Russian Fuel Card Company [Member] USD ($)	Jun. 15, 2012 Russian Fuel Card Company [Member] Subsequent Event [Member] USD ($)	Dec. 31, 2011 Allstar Business Solutions Limited [Member] USD ($)	Dec. 31, 2011 Allstar Business Solutions Limited [Member] GBP (£)	Sep. 30, 2012 Other Acquisition [Member] USD ($)	Jul. 03, 2012 All 2012 Acquisitions [Member] USD ($)
Business Acquisition, Contingent Consideration [Line Items]
Aggregate purchase price	$ 206.8	$ 333.8			$ 312.0	£ 200.0		$ 155.7
Deferred payment	11.30		11.30	11.25
Contingent earn-out payment	5.1						5.1
Purchase price, net of cash and cash equivalents received	2.1
Number of foreign acquisitions		2
Aggregate carrying amount of customer-related intangible assets	86.1
Goodwill	66.3
Deferred tax liabilities	19.9
Accrued liabilities acquired	$ 0.7