Commitments And Contingencies (Details) (USD $)	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Loss Contingencies [Line Items]
Lease expense for operating leases	$ 5,400,000	$ 3,700,000	$ 3,300,000
Additional bonding capacity	150,900,000
S&I [Member]
Loss Contingencies [Line Items]
Guarantee liability	7,000,000
Line of credit facility	12,100,000
Financial Standby Letter of Credit [Member]
Loss Contingencies [Line Items]
Guarantee liability	36,600,000
Performance Guarantee [Member]
Loss Contingencies [Line Items]
Guarantee liability	$ 249,100,000