Business Acquisitions, Goodwill and Intangible Assets (Details 2) (USD $)	9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Professional Technical Services	Jun. 30, 2012 Professional Technical Services	Jun. 30, 2012 Management Support Services	Jun. 30, 2013 Management Support Services	Sep. 30, 2012 Management Support Services
Changes in the carrying value of goodwill by reporting segment
Goodwill at the beginning of the period	$ 1,775,352,000	$ 2,086,300,000	$ 1,608,600,000	$ 1,733,900,000	$ 352,400,000	$ 166,800,000	$ 166,800,000
Post-Acquisition Adjustments		7,200,000		(300,000)	7,500,000
Foreign Exchange Impact	(43,400,000)	5,500,000	(43,400,000)	5,500,000
Acquired	65,300,000	10,700,000	65,300,000	10,700,000
Goodwill at the end of the period	$ 1,797,314,000	$ 2,109,700,000	$ 1,630,500,000	$ 1,749,800,000	$ 359,900,000	$ 166,800,000	$ 166,800,000