Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	Feb. 28, 2018	Aug. 31, 2017
Inventory Disclosure [Abstract]
Grain and oilseed	$ 1,515,669	$ 1,145,285
Energy	779,629	755,886
Crop nutrients	413,719	248,699
Feed and farm supplies	762,513	353,130
Processed grain and oilseed	168,354	49,723
Other	10,274	23,862
Total inventories	$ 3,650,158	$ 2,576,585