Derivatives and Risk Management (Details 4) (Cash Flow Hedging [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Nov. 30, 2011	Nov. 30, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Gain, (loss), net of taxes for cash flow hedges recognized in AOCI	$ (1,186)	$ 54
Commodity [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain, (loss), net of taxes for cash flow hedges recognized in AOCI	(25)	37
Foreign Exchange [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain, (loss), net of taxes for cash flow hedges recognized in AOCI	$ (1,161)	$ 17