Derivatives and Risk Management (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Nov. 30, 2011	Nov. 30, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) before taxes for derivatives not designated as hedges	$ (3,923)	$ (13,048)
Commodity [Member] | Cost of goods sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) before taxes for derivatives not designated as hedges	3,577	(10,286)
Foreign Exchange [Member] | Net Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) before taxes for derivatives not designated as hedges	(108)	(18)
Foreign Exchange [Member] | Cost of goods sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) before taxes for derivatives not designated as hedges	(233)	580
Foreign Exchange [Member] | SG&A expenses [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) before taxes for derivatives not designated as hedges	$ (7,159)	$ (3,324)