Fair Value Measurements - Fair Value Measurements (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Feb. 29, 2016	Aug. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Assets, Fair Value Disclosure	$ 70,710	$ 72,571
Other Assets, Fair Value Disclosure	10,579	10,905
Total assets	513,140	596,917
Foreign Currency Contracts, Liability, Fair Value Disclosure		37,598
Total liabilities	311,643	546,751
Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	23,971	23,155
Foreign Currency Contracts, Liability, Fair Value Disclosure	22,041
Commodity and Freight Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	384,185	476,070
Derivative Liability	261,710	427,052
Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	23,695	14,216
Derivative Liability	3,737	6,119
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, Fair Value Disclosure	70,710	72,571
Other Assets, Fair Value Disclosure	10,579	10,905
Total assets	106,898	130,452
Foreign Currency Contracts, Liability, Fair Value Disclosure		0
Total liabilities	43,705	58,873
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	0
Foreign Currency Contracts, Liability, Fair Value Disclosure	0
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	25,609	46,976
Derivative Liability	43,705	58,873
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, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	0	0
Total assets	406,242	466,465
Foreign Currency Contracts, Liability, Fair Value Disclosure		37,598
Total liabilities	243,783	411,896
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	23,971	23,155
Foreign Currency Contracts, Liability, Fair Value Disclosure	22,041
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	358,576	429,094
Derivative Liability	218,005	368,179
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	23,695	14,216
Derivative Liability	3,737	6,119
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Assets, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	0	0
Total assets	0	0
Foreign Currency Contracts, Liability, Fair Value Disclosure		0
Total liabilities	24,155	75,982
Fair Value, Inputs, Level 3 [Member] | 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
Foreign Currency Contracts, Liability, Fair Value Disclosure	0
Fair Value, Inputs, Level 3 [Member] | 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
Fair Value, Inputs, Level 3 [Member] | 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
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] | Fair Value, Inputs, Level 3 [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	$ 24,155	$ 75,982