Members' Equity (Details) - USD ($)		1 Months Ended			6 Months Ended		12 Months Ended
	Dec. 17, 2015	Apr. 30, 2017	Jan. 31, 2017	Jan. 31, 2016	Apr. 30, 2017	Apr. 30, 2016	Oct. 31, 2016
Common Stock, Shares Authorized		30,606			30,606		30,606
Common Units Issued		30,606			30,606		30,606
Membership Units, Outstanding		30,606			30,606		30,606
Distribution Made to Member or Limited Partner, Cash Distributions Paid					$ 11,171,190	$ 9,640,887
Granite Falls Energy, LLC
Distribution Made to Membership, Cash Distribution Paid per Unit				$ 315	$ 365
Distribution Made to Member or Limited Partner, Cash Distributions Paid			$ 11,171,000				$ 9,641,000
Heron Lake BioEnergy, LLC
Distribution Made to Member or Limited Partner, Cash Distributions Paid				$ 3,897,000
Distributions received	$ 1,971,000
Distribution Made to Limited Liability Company (LLC) Member, Distributions Paid, Per Unit				$ 0.05
Units purchased		54,875
Price per unit		$ 0.85			$ 0.85
Total purchase price		$ 47,000
Heron Lake BioEnergy, LLC | Noncontrolling Interest [Member]
Distribution Made to Member or Limited Partner, Cash Distributions Paid	$ 1,926,000			$ 2,007,000
Heron Lake BioEnergy, LLC | Capital Unit, Class A [Member]
Common Units Issued	39,420,949
Heron Lake BioEnergy, LLC | Capital Unit, Class B [Member]
Common Units Issued	15,000,000