Equities Changes in Equity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 28, 2017	Feb. 29, 2016	Feb. 28, 2017	Feb. 29, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			$ 7,866,250
Reversal of prior year redemption estimate			125,257
Patronage Refunds			(103,879)
Redemptions of equities			(13,670)
Equity Issued During Period, Value, New Issues			3,123
Preferred stock dividends			(55,767)
Other, net			2,570
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 14,973	$ (30,182)	223,915	$ 235,992
Net income (loss) attributable to CHS Inc.	14,567	(30,979)	223,717	235,496
Net income (loss) attributable to noncontrolling interests	406	797	198	496
Other comprehensive income (loss), net of tax	14,778	$ (10,947)	284	$ (14,500)
Estimated 2017 cash patronage refunds			(61,982)
Estimated 2017 equity redemptions			(24,507)
Ending Balance	7,961,594		7,961,594
Capital equity certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			3,932,513
Reversal of prior year redemption estimate			(153,711)
Patronage Refunds			153,589
Redemptions of equities			(12,792)
Equity Issued During Period, Value, New Issues			3,123
Other, net			(105)
Estimated 2017 equity redemptions			(24,507)
Ending Balance	3,898,110		3,898,110
Nonpatronage Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			22,894
Reversal of prior year redemption estimate			0
Patronage Refunds			0
Redemptions of equities			(82)
Other, net			(64)
Ending Balance	22,748		22,748
Non-qualified Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			281,767
Reversal of prior year redemption estimate			0
Patronage Refunds			0
Redemptions of equities			(796)
Other, net			(26)
Ending Balance	280,945		280,945
Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			2,244,132
Redemptions of equities			0
Other, net			(18)
Ending Balance	2,244,114		2,244,114
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			(211,726)
Other comprehensive income (loss), net of tax			284
Ending Balance	(211,442)		(211,442)
Capital Reserves [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			1,582,380
Reversal of prior year redemption estimate			278,968
Patronage Refunds			(257,468)
Preferred stock dividends			(55,767)
Other, net			3,936
Net income (loss) attributable to CHS Inc.			223,717
Estimated 2017 cash patronage refunds			(61,982)
Ending Balance	1,713,784		1,713,784
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			14,290
Other, net			(1,153)
Net income (loss) attributable to noncontrolling interests			198
Ending Balance	$ 13,335		$ 13,335