Derivative Financial Instruments and Hedging Activities Derivatives (Details) (USD $)																9 Months Ended
	May 31, 2014	Aug. 31, 2013	May 31, 2013	May 31, 2014 Commodity and Freight Derivatives [Member]	Aug. 31, 2013 Commodity and Freight Derivatives [Member]	May 31, 2013 Commodity and Freight Derivatives [Member]	May 31, 2014 Foreign Exchange Contract [Member]	Aug. 31, 2013 Foreign Exchange Contract [Member]	May 31, 2013 Foreign Exchange Contract [Member]	May 31, 2014 Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	Aug. 31, 2013 Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	May 31, 2013 Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	May 31, 2014 Not Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	Aug. 31, 2013 Not Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	May 31, 2013 Not Designated as Hedging Instrument [Member] Interest Rate Swap [Member]	May 31, 2014 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Reclassification out of Accumulated Other Comprehensive Income [Member]	May 31, 2014 Fair Value Hedging [Member] Interest Rate Swap [Member]
Purchase and Sales Contracts [Line Items]
Gain on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring																$ 13,500,000
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	492,202,000	445,823,000	491,783,000	492,095,000	415,566,000	477,580,000	105,000	6,122,000	5,043,000	2,000	24,135,000	9,160,000		0
Derivative Asset, Fair Value, Gross Asset	544,382,000	499,890,000	524,461,000	544,198,000	468,673,000	510,258,000	182,000	7,079,000	5,043,000	2,000	24,135,000	9,160,000		3,000
Derivative Asset, Collateral, Obligation to Return Cash, Offset	0	0	0	0	0	0	0	0	0	0	0	0		0
Derivative Asset, Fair Value, Gross Amount Not Offset on Balance Sheet	52,180,000	54,067,000	32,678,000	52,103,000	53,107,000	32,678,000	77,000	957,000	0	0	0	0		3,000
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	360,291,000	409,408,000	367,375,000	358,045,000	404,195,000	363,188,000	2,076,000	4,968,000	3,883,000				170,000	245,000	304,000
Derivative Liability, Fair Value, Gross Liability	412,471,000	465,066,000	456,476,000	410,148,000	458,893,000	452,289,000	2,153,000	5,925,000	3,883,000				170,000	248,000	304,000
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	1,591,000	56,423,000	0	1,591,000	56,423,000	0	0	0				0	0	0
Derivative Liability, Fair Value, Gross Amount Not Offset on Balance Sheet	52,180,000	54,067,000	32,678,000	52,103,000	53,107,000	32,678,000	77,000	957,000	0				0	3,000	0
Derivative Asset, Notional Amount																	$ 130,000,000