Equities Changes in Equity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		37 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014	Jun. 30, 2017	Jan. 30, 2015	Sep. 30, 2014	Aug. 31, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reversal of prior year patronage and redemption estimates			$ 385,096
Patronage distribution			(277,020)
Equity Certificates Repurchased and Retired During Period, Value			(114,048)
Equities issued			989,728
Dividends, Preferred Stock			(105,223)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders			(430)
Other, net			(4,380)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 177,835	$ 379,873	649,063	$ 883,522
Net income attributable to CHS Inc.	178,050	379,455	649,567	881,710
Net income (loss) attributable to noncontrolling interests	(215)	418	(504)	1,812
Other Comprehensive Income (Loss), Net of Tax	2,128	$ 6,198	(3,510)	$ (2,368)
Patronage Refunds, Estimated			(174,600)
Equity redemptions, estimate			(90,100)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	7,721,420		7,721,420					$ 6,466,844
Capital equity certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reversal of prior year patronage and redemption estimates			(276,966)
Patronage distribution			396,443
Equity Certificates Repurchased and Retired During Period, Value			(113,484)
Equities issued			12,365
Other, net			(243)
Equity redemptions, estimate			(90,100)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	3,436,488		3,436,488					3,508,473
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders			(430)
Other, net			(6,177)
Net income (loss) attributable to noncontrolling interests			(504)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	11,225		11,225					18,336
Nonpatronage Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reversal of prior year patronage and redemption estimates			0
Patronage distribution			0
Equity Certificates Repurchased and Retired During Period, Value			(131)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	23,125		23,125					23,256
Non-qualified Equity Certificates [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reversal of prior year patronage and redemption estimates			(148,579)
Patronage distribution			147,715
Equity Certificates Repurchased and Retired During Period, Value			(453)
Other, net			(606)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	282,776		282,776					284,699
Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reversal of prior year patronage and redemption estimates			0
Patronage distribution			0
Equity Certificates Repurchased and Retired During Period, Value			0
Equities issued			977,363
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	2,167,540		2,167,540					1,190,177
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reversal of prior year patronage and redemption estimates			0
Patronage distribution			0
Equity Certificates Repurchased and Retired During Period, Value			0
Other Comprehensive Income (Loss), Net of Tax			(3,510)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(160,267)		(160,267)					(156,757)
Capital Reserves [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reversal of prior year patronage and redemption estimates			810,641
Patronage distribution			(821,178)
Equity Certificates Repurchased and Retired During Period, Value			$ 20
Equities issued
Dividends, Preferred Stock			$ (105,223)
Other, net			2,646
Net income attributable to CHS Inc.			649,567
Patronage Refunds, Estimated			(174,600)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,960,533		1,960,533					$ 1,598,660
Class B, Series 4 Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Preferred Stock, Redemption Amount						$ 517,500
Proceeds from Issuance of Preferred Stock, net of Issuance Costs			$ 501,000
Preferred Stock, Dividend Rate, Percentage			7.50%
Preferred Stock, Shares Issued						20,700,000
Class B Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Value of Preferred Stock available to be sold under Shelf Registration					$ 2,000,000
Class B, Series 3 Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Preferred Stock, Redemption Amount							$ 492,500
Proceeds from Issuance of Preferred Stock, net of Issuance Costs			$ 476,700
Preferred Stock, Dividend Rate, Percentage			6.75%
Preferred Stock, Shares Issued							19,700,000
London Interbank Offered Rate (LIBOR) [Member] | Class B, Series 3 Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Preferred Stock, Basis Spread on Dividend Rate Percentage			4.155%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Class B, Series 3 Preferred Stock [Member]
Schedule of Capitalization, Equity [Line Items]
Preferred Stock, Basis Spread on Dividend Rate Percentage			8.00%