Investments Equity Method investments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 28, 2018	Feb. 28, 2017	Feb. 28, 2018	Feb. 28, 2017
Schedule of Equity Method Investments [Line Items]
Net income (loss) attributable to CHS Inc.	$ 166,674	$ 14,567	$ 346,757	$ 223,717
CF Nitrogen LLC [Member]
Schedule of Equity Method Investments [Line Items]
Net Sales			1,084,270	1,024,409
Gross Profit			135,649	125,966
Net earnings			128,803	87,798
Net income (loss) attributable to CHS Inc.			$ 44,347	$ 36,253