Business Combinations (Narrative) (Details) Share data in Thousands, except Per Share data, unless otherwise specified	12 Months Ended				0 Months Ended	12 Months Ended				0 Months Ended	12 Months Ended								12 Months Ended
	Sep. 30, 2013 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2013 2013 acquisitions USD ($)	Jul. 03, 2011 GlobalExpense USD ($)	Sep. 30, 2013 GlobalExpense USD ($)	Sep. 30, 2012 GlobalExpense USD ($)	Sep. 30, 2012 GlobalExpense GBP (£)	Sep. 30, 2011 GlobalExpense USD ($)	Jan. 24, 2011 Tripit USD ($)	Sep. 30, 2013 Tripit USD ($)	Jul. 24, 2013 Tripit USD ($)	Sep. 30, 2011 Tripit USD ($)	Jan. 24, 2011 Top-Up Payment Recorded As Part Of Purchase Consideration Tripit USD ($)	Jan. 24, 2011 Top Up Payment Subject To Continued Employment Tripit USD ($)	Sep. 30, 2012 Top Up Payment Recorded As Liability Tripit USD ($)	Sep. 30, 2011 Top Up Payment Recorded As Liability Tripit USD ($)	Sep. 30, 2011 Top Up Payment Will Be Recorded During Requisite Service Period Tripit USD ($)	Sep. 30, 2013 Minimum	Sep. 30, 2013 Minimum 2013 acquisitions	Sep. 30, 2013 Maximum	Sep. 30, 2013 Maximum 2013 acquisitions
Business Acquisition [Line Items]
Payments for acquisitions, net of cash acquired	$ (83,755,000)	$ (68,266,000)	$ (42,424,000)	$ 83,755,000
Acquisition-related contingent consideration	3,182,000	22,692,000		3,182,000	2,600,000		3,200,000	2,000,000		28,900,000				17,400,000	11,500,000
Acquisition-related liabilities	2,231,000	4,488,000		2,231,000
Finite-lived Intangible Assets Acquired				35,700,000	10,350,000					19,604,000
Intangible asset useful life																			2 years	2 years	13 years	13 years
Goodwill				40,715,000	13,135,000					69,205,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Excluding Intangibles and Goodwill, Net				4,500,000
Deferred tax assets				10,700,000
Business Acquisition, Goodwill, Expected Tax Deductible Amount				12,700,000
Date of acquisition					Jul. 01, 2011					Jan. 24, 2011
Cash paid to acquire entity					19,200,000					24,700,000
Contingent consideration arrangements, High range of outcomes				5,500,000				2,000,000				38,300,000
Transaction costs									906,000				1,900,000
Number of shares issued for acquisition										814
Value of shares issued for acqusition										41,200,000
Fair value of replacement awards										9,900,000
Fair value replacement awards precombination service period										3,600,000
Contingent consideration applicability term												30
Guaranteed market value of consideration issued on payment date												82,100,000
Guaranteed market value of consideration issued per share on payment date												$ 100.90
Fair value of contingent consideration													35,400,000			22,700,000	30,900,000	4,500,000
Payments for contingent consideration						$ 3,087,000					$ 11,316,000