Investments - Narrative (Details) $ in Thousands, T in Millions		3 Months Ended		9 Months Ended
	Feb. 01, 2016 USD ($)	May 31, 2017 USD ($) T Tons	May 31, 2016 USD ($)	May 31, 2017 USD ($) T Tons	May 31, 2016 USD ($)	Feb. 01, 2096 USD ($)	Aug. 31, 2016 USD ($)
Schedule of Equity Method Investments [Line Items]
Equity (income) loss from investments		$ (48,393)	$ (72,453)	$ (124,521)	$ (131,819)
Cost Method Investments		130,909		130,909			$ 127,577
Investments		$ 3,841,749		$ 3,841,749			3,795,976
CF Nitrogen LLC [Member]
Schedule of Equity Method Investments [Line Items]
Payments to Acquire Equity Method Investments	$ 2,800,000
Ownership percentage	11.40%
Supply agreement, term	80 years
Maximum annual granular urea eligible for purchase | T		1.1		1.1
Maximum annual UAN eligible for purchase | Tons		580,000		580,000
Equity Method Investments		$ 2,808,993		$ 2,808,993			2,796,323
Ventura Foods, LLC
Schedule of Equity Method Investments [Line Items]
Equity Method Investments		374,006		374,006			369,487
TEMCO, LLC
Schedule of Equity Method Investments [Line Items]
Equity Method Investments		41,581		41,581			44,578
Ardent Mills LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments		$ 195,869		$ 195,869			194,986
Cargill, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership of joint venture partner		50.00%		50.00%
Nitrogen Production [Member]
Schedule of Equity Method Investments [Line Items]
Equity (income) loss from investments		$ (24,534)	(41,257)	$ (60,787)	(53,112)
Foods [Member]
Schedule of Equity Method Investments [Line Items]
Equity (income) loss from investments		$ (9,920)	(19,922)	$ (28,850)	(55,449)
Foods [Member] | Ventura Foods, LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage		50.00%		50.00%
Equity value exceeding carrying value		$ 12,900		$ 12,900
Corporate and Other
Schedule of Equity Method Investments [Line Items]
Equity (income) loss from investments		$ (4,349)	(4,043)	$ (14,774)	(11,619)
Corporate and Other | Ardent Mills LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage		12.00%		12.00%
Number of parent companies		3		3
Ag [Member]
Schedule of Equity Method Investments [Line Items]
Equity (income) loss from investments		$ (9,199)	$ (5,931)	$ (18,071)	$ (8,152)
Ag [Member] | TEMCO, LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage		50.00%		50.00%
Scenario, Forecast [Member] | Nitrogen Production [Member] | CF Nitrogen LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments						$ 0
Miscellaneous Investments [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments		$ 290,391		$ 290,391			$ 263,025