Investments Equity Method investments (Details) - USD ($) $ in Thousands	3 Months Ended
	Nov. 30, 2020	Nov. 30, 2019	Aug. 31, 2020
Schedule of Equity Method Investments [Line Items]
Cost Method Investments	$ 124,130		$ 123,955
Net income (loss) attributable to CHS Inc.	69,671	$ 177,882
Gross Profit	178,104	325,543
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	69,369	178,737
Other Equity Method Investments [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	258,049		253,182
CF Nitrogen LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	2,684,306		2,662,618
Net income (loss) attributable to CHS Inc.	21,688	34,834
Revenues	606,340	649,638
Gross Profit	94,068	149,573
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	81,173	140,490
Ventura Foods, LLC
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	388,869		381,351
Net income (loss) attributable to CHS Inc.	12,551	13,063
Revenues	579,074	629,360
Gross Profit	72,522	106,140
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	25,102	26,126
Ardent Mills LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	211,120		$ 208,927
TEMCO and Ardent Mills
Schedule of Equity Method Investments [Line Items]
Net income (loss) attributable to CHS Inc.	12,627	(402)
Revenues	2,795,940	1,587,493
Gross Profit	131,904	97,570
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 64,554	$ 35,451