Derivatives Reconcilation of Gross and Net (Details) - USD ($) $ in Thousands	Aug. 31, 2017	Aug. 31, 2016
Reconciliation of gross and net fair value of assets and liabilities subject to offsetting arrangements [Line Items]
Derivative Assets	$ 428,930	$ 543,821
Derivative asset, fair value, gross amount not offset on Balance sheet	38,716	32,876
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	390,214	510,945
Derivative Liability, Fair Value, Gross Liability	330,400	513,599
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	3,898	811
Derivative liability, fair value, gross amount not offset on balance sheet	38,716	32,876
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	287,786	479,912
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Reconciliation of gross and net fair value of assets and liabilities subject to offsetting arrangements [Line Items]
Derivative Assets	9,978	22,078
Derivative asset, fair value, gross amount not offset on Balance sheet	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	9,978	22,078
Derivative Liability, Fair Value, Gross Liability	707
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0
Derivative liability, fair value, gross amount not offset on balance sheet	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	707
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Reconciliation of gross and net fair value of assets and liabilities subject to offsetting arrangements [Line Items]
Derivative Assets	8,771	21,551
Derivative asset, fair value, gross amount not offset on Balance sheet	3,636	9,187
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	5,135	12,364
Derivative Liability, Fair Value, Gross Liability	19,931	22,289
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative liability, fair value, gross amount not offset on balance sheet	3,636	9,187
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	16,295	13,102
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Reconciliation of gross and net fair value of assets and liabilities subject to offsetting arrangements [Line Items]
Derivative Liability, Fair Value, Gross Liability		8
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0
Derivative liability, fair value, gross amount not offset on balance sheet		0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		8
Not Designated as Hedging Instrument [Member] | Embedded Derivative Financial Instruments [Member]
Reconciliation of gross and net fair value of assets and liabilities subject to offsetting arrangements [Line Items]
Derivative Assets	25,533
Derivative asset, fair value, gross amount not offset on Balance sheet	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	25,533
Not Designated as Hedging Instrument [Member] | Commodity and Freight Derivatives [Member]
Reconciliation of gross and net fair value of assets and liabilities subject to offsetting arrangements [Line Items]
Derivative Assets	384,648	500,192
Derivative asset, fair value, gross amount not offset on Balance sheet	35,080	23,689
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	349,568	476,503
Derivative Liability, Fair Value, Gross Liability	309,762	491,302
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	3,898	811
Derivative liability, fair value, gross amount not offset on balance sheet	35,080	23,689
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	$ 270,784	$ 466,802