Restatement of Previously Issued Financial Information - Summary of Impacts of the Restatement Adjustments on Previously Reported Consolidated Statements of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Feb. 28, 2019	Nov. 30, 2018	Feb. 28, 2018	Nov. 30, 2017	Feb. 28, 2019	Feb. 28, 2018
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)	$ 248,304	$ 347,115	$ 165,959	$ 187,182	$ 595,419	$ 353,141
Other comprehensive income (loss), net of tax:
Postretirement benefit plan activity	2,002		3,142		4,103	4,736
Unrealized net gain (loss) on available for sale investments	0		3,554		0	7,194
Cash flow hedges	9,969		1,063		8,662	1,059
Foreign currency translation adjustment			2,352			141
Other comprehensive income (loss), net of tax	14,884	$ 389	10,111	$ 3,019	15,273	13,130
Comprehensive income	263,188		176,070		610,692	366,271
Less comprehensive income attributable to noncontrolling interests	(462)		(48)		(851)	(512)
Comprehensive income attributable to CHS Inc.	$ 263,650		176,118		$ 611,543	366,783
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)			166,626			346,245
Other comprehensive income (loss), net of tax:
Postretirement benefit plan activity			3,141			7,338
Unrealized net gain (loss) on available for sale investments			3,554			7,194
Cash flow hedges			1,063			1,059
Foreign currency translation adjustment			2,461			(146)
Other comprehensive income (loss), net of tax			10,219			15,445
Comprehensive income			176,845			361,690
Less comprehensive income attributable to noncontrolling interests			(48)			(512)
Comprehensive income attributable to CHS Inc.			176,893			362,202
Restatement Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)			(667)			6,896
Other comprehensive income (loss), net of tax:
Postretirement benefit plan activity			1			(2,602)
Unrealized net gain (loss) on available for sale investments			0			0
Cash flow hedges			0			0
Foreign currency translation adjustment			(109)			287
Other comprehensive income (loss), net of tax			(108)			(2,315)
Comprehensive income			(775)			4,581
Less comprehensive income attributable to noncontrolling interests			0			0
Comprehensive income attributable to CHS Inc.			$ (775)			$ 4,581