Inventories - Schedule of Inventories (Details) (USD $) In Thousands, unless otherwise specified	Nov. 30, 2012	Aug. 31, 2012	Nov. 30, 2011
Inventory Disclosure [Abstract]
Grain and Oilseed	$ 2,089,348	$ 1,625,865	$ 1,375,456
Energy	668,990	701,348	799,061
Crop nutrients	331,666	401,655	395,551
Feed and farm supplies	440,050	384,178	384,804
Processed grain and oilseed	100,059	76,892	47,492
Other	11,631	14,034	10,978
Inventories	$ 3,641,744	$ 3,203,972	$ 3,013,342