Investments - Schedule of Investments (Details) (USD $) In Thousands, unless otherwise specified	Aug. 31, 2013	Aug. 31, 2012
Schedule of Equity Method Investments [Line Items]
Investments total	$ 765,946	$ 673,388
Ventura Foods, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	309,480	292,393
Horizon Milling, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	92,635	78,372
TEMCO, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	63,547	60,734
Horizon Milling G.P.
Schedule of Equity Method Investments [Line Items]
Equity method investments	19,314	16,727
Land O'Lakes, Inc.
Schedule of Equity Method Investments [Line Items]
Cost method investments	66,255	58,382
Ag Processing Inc.
Schedule of Equity Method Investments [Line Items]
Cost method investments	19,970	19,577
Other
Schedule of Equity Method Investments [Line Items]
Equity and cost method investments	$ 194,745	$ 147,203