Investments - Schedule of Investments (Details) - USD ($) $ in Thousands	Aug. 31, 2018	May 31, 2018	Feb. 28, 2018	Nov. 30, 2017	Aug. 31, 2017	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016
Schedule of Equity Method Investments [Line Items]
Cost method investments	$ 122,788				$ 131,605
Investments	3,711,925	$ 3,787,163	$ 3,752,876	$ 3,777,000	3,750,993	$ 3,841,749	$ 3,802,379	$ 3,828,899
CF Industries Nitrogen, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	2,735,073				2,756,076
Ventura Foods, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	360,150				347,016
Ardent Mills, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	205,898				206,529
Other equity method investments
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 288,016				$ 309,767