Equities Changes in Equity (Details) - USD ($) $ in Thousands	3 Months Ended
	Nov. 30, 2017	Nov. 30, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ 7,905,825
Reversal of prior year redemption estimates	1,561
Redemptions of equities	(1,561)
Preferred stock dividends	(84,334)
Other, net	2,043
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	179,619	$ 208,942
Net income (loss) attributable to CHS Inc.	180,083	209,150
Net income (loss) attributable to noncontrolling interests	(464)	(208)
Other comprehensive income (loss), net of tax	5,225	(14,494)
Estimated 2018 cash patronage refunds	(50,702)
Estimated 2018 equity redemptions	(19,901)
Ending Balance	7,937,775
Capital equity certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	3,906,426
Reversal of prior year redemption estimates	1,561
Redemptions of equities	(1,449)
Other, net	(1,498)
Estimated 2018 equity redemptions	(19,901)
Ending Balance	3,885,139
Nonpatronage Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	29,836
Reversal of prior year redemption estimates	0
Redemptions of equities	(53)
Other, net	(66)
Ending Balance	29,717
Non-qualified Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	405,387
Reversal of prior year redemption estimates	0
Redemptions of equities	(59)
Other, net	(344)
Ending Balance	404,984
Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	2,264,038
Redemptions of equities	0
Ending Balance	2,264,038
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(183,670)	(211,726)
Other comprehensive income (loss), net of tax	5,225	(14,494)
Ending Balance	(178,445)	$ (226,220)
Capital Reserves [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,471,217
Reversal of prior year redemption estimates	0
Preferred stock dividends	(84,334)
Other, net	3,954
Net income (loss) attributable to CHS Inc.	180,083
Estimated 2018 cash patronage refunds	(50,702)
Ending Balance	1,520,218
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	12,591
Other, net	(3)
Net income (loss) attributable to noncontrolling interests	(464)
Ending Balance	$ 12,124