Summary of Significant Accounting Policies - Pretax Gains (Losses) On Derivatives Not Accounted For As Hedging Instruments (Details) (Not Designated as Hedging Instrument, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Nov. 30, 2013	Nov. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain (loss) on derivative instruments	$ (20,212)	$ (329,978)
Commodity and Freight Derivatives [Member] | Cost of goods sold
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain (loss) on derivative instruments	(19,789)	(328,284)
Foreign Exchange Contract [Member] | Cost of goods sold
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain (loss) on derivative instruments	(422)	(1,685)
Interest rate derivatives | Interest, net
Derivative Instruments, Gain (Loss) [Line Items]
Pretax gain (loss) on derivative instruments	$ (1)	$ (9)