Fair Value Measurements Recurring Fair Value Measurements by Level (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	May. 31, 2015	Aug. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Inventory, Current, Fair Value Disclosure	$ 1,227,368	$ 921,554
Other Assets, Fair Value Disclosure	11,150	8,778
Assets, Fair Value Disclosure	1,919,265	1,617,482
Liabilities, Fair Value Disclosure	638,392	714,907
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Inventory, Current, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	11,150	8,778
Assets, Fair Value Disclosure	159,285	173,108
Liabilities, Fair Value Disclosure	131,312	119,938
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Inventory, Current, Fair Value Disclosure	1,227,368	921,554
Other Assets, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	1,759,980	1,444,374
Liabilities, Fair Value Disclosure	397,860	480,052
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Inventory, Current, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	$ 109,220	$ 114,917