Fair Value Measurements - Fair Value Measurements (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Aug. 31, 2015	Aug. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Assets, at Fair Value	$ 72,571	$ 83,217
Other assets	10,905	8,778
Total assets	596,917	695,928
Foreign Currency Contracts, Liability, Fair Value Disclosure	37,598	2,248
Total liabilities	546,751	714,907
Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	23,155	2,523
Commodity and Freight Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	476,070	597,210
Derivative Liability	427,052	597,612
Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	14,216	4,200
Derivative Liability	6,119	130
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Assets, at Fair Value	72,571	83,217
Other assets	10,905	8,778
Total assets	130,452	173,108
Foreign Currency Contracts, Liability, Fair Value Disclosure	0	2,248
Total liabilities	58,873	119,938
Quoted Prices in Active Markets for Identical Assets (Level 1) | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	0	2,523
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commodity and Freight Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	46,976	78,590
Derivative Liability	58,873	117,690
Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Derivative Liability	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Assets, at Fair Value	0	0
Other assets	0	0
Total assets	466,465	522,820
Foreign Currency Contracts, Liability, Fair Value Disclosure	37,598	0
Total liabilities	411,896	480,052
Significant Other Observable Inputs (Level 2) | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	23,155	0
Significant Other Observable Inputs (Level 2) | Commodity and Freight Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	429,094	518,620
Derivative Liability	368,179	479,922
Significant Other Observable Inputs (Level 2) | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	14,216	4,200
Derivative Liability	6,119	130
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Assets, at Fair Value	0	0
Other assets	0	0
Total assets	0	0
Foreign Currency Contracts, Liability, Fair Value Disclosure	0	0
Total liabilities	75,982	114,917
Significant Unobservable Inputs (Level 3) | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	0	0
Significant Unobservable Inputs (Level 3) | Commodity and Freight Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Derivative Liability	0	0
Significant Unobservable Inputs (Level 3) | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0	0
Derivative Liability	0	0
NCRA [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accrued liability for contingent crack spread payments related to purchase of noncontrolling interest	75,982	114,917
NCRA [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accrued liability for contingent crack spread payments related to purchase of noncontrolling interest	0	0
NCRA [Member] | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accrued liability for contingent crack spread payments related to purchase of noncontrolling interest	0	0
NCRA [Member] | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accrued liability for contingent crack spread payments related to purchase of noncontrolling interest	$ 75,982	$ 114,917