Derivatives and Risk Management (Details 5) (USD $) In Thousands	Aug. 31, 2011	Aug. 31, 2010
Derivatives, Fair Value [Line Items]
Derivative assets (other current assets and other assets)	$ 52,858	$ 35,052
Commodity [Member]
Derivatives, Fair Value [Line Items]
Derivative assets (other current assets and other assets) Designated as Hedging Instrument, Fair Value	17	80
Derivative assets (other current assets and other assets) Not Designated as Hedging Instrument, Fair Value	2,329	911
Foreign Exchange [Member]
Derivatives, Fair Value [Line Items]
Derivative assets (other current assets and other assets) Designated as Hedging Instrument, Fair Value	893	435
Derivative assets (other current assets and other assets) Not Designated as Hedging Instrument, Fair Value	970	1,188
Current interest Rate [Member]
Derivatives, Fair Value [Line Items]
Derivative assets (other current assets and other assets) Designated as Hedging Instrument, Fair Value	19,134	12,173
Long Term interest Rate [Member]
Derivatives, Fair Value [Line Items]
Derivative assets (other current assets and other assets) Designated as Hedging Instrument, Fair Value	$ 29,515	$ 20,265