Derivatives And Risk Management (Derivative Assets) (Details) (USD $) In Thousands, unless otherwise specified	Aug. 31, 2012		Aug. 31, 2011
Derivatives, Fair Value [Line Items]
Derivative assets (other current assets and other assets)	$ 1,875	[1]	$ 52,858	[1]
Commodity [Member] | Designated [Member]
Derivatives, Fair Value [Line Items]
Derivative assets (other current assets and other assets)	0		17
Commodity [Member] | Not designated [Member]
Derivatives, Fair Value [Line Items]
Derivative assets (other current assets and other assets)	407		2,329
Foreign exchange [Member] | Designated [Member]
Derivatives, Fair Value [Line Items]
Derivative assets (other current assets and other assets)	670		893
Foreign exchange [Member] | Not designated [Member]
Derivatives, Fair Value [Line Items]
Derivative assets (other current assets and other assets)	798		970
Current interest rate [Member] | Designated [Member]
Derivatives, Fair Value [Line Items]
Derivative assets (other current assets and other assets)	0		19,134
Long-term interest rate [Member] | Designated [Member]
Derivatives, Fair Value [Line Items]
Derivative assets (other current assets and other assets)	$ 0		$ 29,515

[1] * Derivative assets and liabilities do not include the hedged (underlying) items designated as fair value hedges.