Commitments and Contingencies Narrative (Details)	12 Months Ended
	Oct. 31, 2015 USD ($) MMBTU bu	Oct. 31, 2014 USD ($) mi	Oct. 31, 2013 USD ($)
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Selling and Marketing Expense	$ 1,234,000	$ 1,318,000	$ 1,031,000
Entity-Wide Revenue, Major Customer, Percentage	100.00%
Natural Gas [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Future Commitment, Pipeline | mi		9.5
Future Commitment, DT | MMBTU	1,400,000
Corn Oil [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Fees and Commissions	$ (125,000)	$ (112,000)	(74,000)
Distillers Grains [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Written Notice	P90D
Contract, Initial Length	P1Y
Fees and Commissions	$ (421,000)	$ (518,000)	$ (745,000)
Granite Falls Energy [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	99.00%	99.00%	100.00%
Granite Falls Energy [Member] | Natural Gas [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
future commitment, percent of anticipated usage	75.00%
Granite Falls Energy [Member] | Corn Oil [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Future Commitment, Dollar	$ 220,000
Granite Falls Energy [Member] | Ethanol Contracts [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Future Commitment, Dollar	$ 2,389,000
Revenue Concentration, Future Commitment	15.00%
Granite Falls Energy [Member] | Distillers Grains [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Future Commitment, Dollar	$ 1,923,000
Revenue Concentration, Future Commitment	45.00%
Granite Falls Energy [Member] | Initial Length [Member] | Ethanol Contracts [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Written Notice	December 31, 2016
Granite Falls Energy [Member] | Renewal Notice [Member] | Ethanol Contracts [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Written Notice	P3M
Granite Falls Energy [Member] | Corn Contracts [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
forward contracts	$ 0
Accounts Payable	1,486,000	$ 1,998,000
Purchases For Inventory	$ 75,018,000	$ 82,955,000	$ 153,216,000
Granite Falls Energy [Member] | Corn Oil [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Written Notice	P90D
Contract, Initial Length	P1Y
Heron Lake Bioenergy [Member] | Corn Oil [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Future Commitment, Dollar	$ 383,000
Heron Lake Bioenergy [Member] | Ethanol Contracts [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Future Commitment, Dollar	$ 2,366,000
Revenue Concentration, Future Commitment	15.00%
Heron Lake Bioenergy [Member] | Distillers Grains [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Future Commitment, Dollar	$ 151,000
Heron Lake Bioenergy [Member] | Corn Oil [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Written Notice	P90D
Contract, Initial Length	P1Y
Corn Contracts [Member] | Granite Falls Energy [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Inventory Dollars, Outside Storage	$ 1,300,000
Inventory, Outside storage | bu	380,000
Corn Contracts [Member] | Heron Lake Bioenergy [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Inventory, Outside storage | bu	2,604,000