Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	May 31, 2019	Aug. 31, 2018
Inventory Disclosure [Abstract]
Grain and oilseed	$ 1,115,510	$ 1,298,522
Energy	899,150	715,161
Agronomy	635,560	246,326
Feed and farm supplies	567,952	391,906
Processed grain and oilseed	104,113	99,426
Other	16,036	17,308
Total inventories	$ 3,338,321	$ 2,768,649