Debt Facilities - Granite Falls Energy And Heron Lake BioEnergy (Details) - USD ($)		6 Months Ended	12 Months Ended
	Nov. 01, 2016	Apr. 30, 2017	Oct. 31, 2016
Line of Credit Facility [Line Items]
Long-term Debt		$ 1,725,833
Less: amounts due within one year		444,123	$ 490,057
Net long term debt		$ 1,281,710	1,393,669
Assessments payable as part of water supply agreement, with interest at 8.73%, due in 2019
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		8.73%
Semi-annual payment		$ 3,942
Note payable to electrical company, due September 2017
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		0.00%
Maintenance fee (as a percent)		1.00%
Monthly payment		$ 6,250
Note payable to noncontrolling interest member of Agrinatural, Interest One Month LIBOR plus 4.0 %
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.00%
Heron Lake BioEnergy, LLC
Line of Credit Facility [Line Items]
Long-term Debt		$ 1,725,833	1,883,726
Less: amounts due within one year		444,123	490,057
Net long term debt		1,281,710	1,393,669
Heron Lake BioEnergy, LLC | City/County Jurisdiction [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding		1,595,000	1,615,000
Heron Lake BioEnergy, LLC | Revolving Term Loan
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding		0	0
Line of Credit Facility, Remaining Borrowing Capacity		17,500,000	$ 21,000,000
Debt Instrument, Fee Amount		2,500
Long-term Debt		$ 28,000,000
Heron Lake BioEnergy, LLC | Revolving Term Loan | CoBank [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage		0.50%
Debt Instrument, Basis Spread on Variable Rate		3.25%
Debt Instrument, Interest Rate During Period		4.25%	3.45%
Heron Lake BioEnergy, LLC | Water Treatment Plant [Member] | City/County Jurisdiction [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 3,600,000
Debt Instrument, Face Amount		$ 735,000
Heron Lake BioEnergy, LLC | Assessments payable as part of water treatment agreement, with interest at 6.55%, due in 2021
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		6.55%
Long-term Debt		$ 1,516,977	$ 1,517,046
Semi-annual payment		$ 189,393
Period of worth of debt		1 year
Deposit on debt service payments		$ 364,000
Ring-neck Energy & Feed, LLC
Line of Credit Facility [Line Items]
Down payment	$ 750,000
Granite Falls Energy, LLC
Line of Credit Facility [Line Items]
Line of Credit Future Reduction, Amount		2,000,000
Granite Falls Energy, LLC | Revolving Term Loan
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding		0	0
Line of Credit Facility, Maximum Borrowing Capacity		18,000,000
Line of Credit Facility, Remaining Borrowing Capacity		$ 8,000,000	10,000,000
Debt Instrument, Covenant Description		The credit facility is secured by substantially all assets of GFE. There are no savings account balance collateral requirements as part of this credit facility.
Heron Lake BioEnergy, LLC | Revolving Term Loan
Line of Credit Facility [Line Items]
Line of Credit Future Reduction, Amount		$ 3,500,000
Heron Lake BioEnergy, LLC | Assessments payable as part of water supply agreement, with interest at 8.73%, due in 2019
Line of Credit Facility [Line Items]
Long-term Debt		77,606	97,930
Heron Lake BioEnergy, LLC | Note payable to electrical company, due September 2017
Line of Credit Facility [Line Items]
Long-term Debt		31,250	68,750
Heron Lake BioEnergy, LLC | Note payable to noncontrolling interest member of Agrinatural, Interest One Month LIBOR plus 4.0 %
Line of Credit Facility [Line Items]
Long-term Debt		$ 100,000	$ 200,000
Minimum [Member] | Heron Lake BioEnergy, LLC | Water Treatment Plant [Member] | City/County Jurisdiction [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		0.50%
Maximum [Member] | Heron Lake BioEnergy, LLC | City/County Jurisdiction [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		8.73%
Maximum [Member] | Granite Falls Energy, LLC
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		4.05%	3.25%
Debt Instrument, Basis Spread on Variable Rate		3.05%
Fagen Energy, LLC Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding		$ 0
Down payment		$ 7,500,000
Maximum period of interest payments		2 years
Debt instrument amortization period after first two years		7 years
Credit facility terms		The Fagen Energy loan  requires annual interest payments only for the first two years of the loan and monthly principal and interest payments for years 3 through 9 based on a 7-year amortization period.  The monthly amortized payments will be re-amortized following any change in interest rate. The entire outstanding principal balance of the loan, plus any accrued and unpaid interest thereon, is due and payable in full on November 1, 2025. GFE is permitted to voluntarily prepay all or any portion of the outstanding balance of this loan at any time without premium or penalty.
LIBOR [Member] | Fagen Energy, LLC Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt instrument, period of moving average on variable rate		1 month
Debt Instrument, Basis Spread on Variable Rate		3.05%
LIBOR [Member] | Fagen Energy, LLC Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.55%
Capital Units [Member] | Ring-neck Energy & Feed, LLC
Line of Credit Facility [Line Items]
Subsidiary or Equity Method Investee, Cumulative Number of Shares Issued for All Transactions	1,500	1,500