Debt Facilities Narrative (Details) (USD $)	12 Months Ended		3 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Jan. 31, 2014	Jul. 30, 2014	Jul. 31, 2013
Line of Credit Facility [Line Items]
Long-term Debt	2,958,647	$ 36,472,763
Revolving Operating Loan [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate Description	"One Month LIBOR Index Rate," plus 265
Revolving Term Loan [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate Description	"One Month LIBOR Index Rate," plus 265
Heron Lake Bioenergy [Member]
Line of Credit Facility [Line Items]
Convertible Subordinated Debt, Noncurrent	0	4,143,000
Debt Instrument, Convertible, Conversion Price	0.30
Debt Conversion, Converted Instrument, Amount	3,936,000
Conversion of Stock, Shares Converted	13,120,000
principal percentage conversion	100.00%
Payments for Repurchase of Redeemable Noncontrolling Interest	207,000
Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions	50.60%	60.80%
Heron Lake Bioenergy [Member] | Revolving Operating Loan [Member]
Line of Credit Facility [Line Items]
Long-term Debt	28,000,000				18,500,000
Letters of Credit Reduction, Amount			3,500,000
Debt Instrument, Fee Amount	2,500
Line of Credit Facility, Amount Outstanding	0	6,263,158		7,500,000
Heron Lake Bioenergy [Member] | Revolving Term Loan [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate Description	LIBOR plus 3.50% but not less than 5%
Line of Credit Facility, Amount Outstanding	0	18,317,800
term note, monthly payments (P&I)	223,000
Debt Instrument, Amortization Period	10 years
Heron Lake Bioenergy [Member] | Natural Gas Pipeline Construction Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.29%
Agrinatural, LLC [Member]
Line of Credit Facility [Line Items]
Long-term Debt					759,000
Line of Credit Facility, Amount Outstanding	300,000	300,000
Agrinatural, LLC [Member] | Natural Gas Pipeline Construction Loan [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	0	1,013,132
Granite Falls Energy [Member]
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	289,000
Granite Falls Energy [Member] | Revolving Term Loan [Member]
Line of Credit Facility [Line Items]
Long-term Debt	18,000,000
Letters of Credit Reduction, Amount	2,000,000
Line of Credit Facility, Amount Outstanding	0	2,513,674
Board of Governors [Member]
Line of Credit Facility [Line Items]
Convertible Subordinated Debt, Noncurrent	4,000,000
Unit Holders, non-Board of Governors [Member]
Line of Credit Facility [Line Items]
Convertible Subordinated Debt, Noncurrent	7,000,000
Minimum [Member] | Revolving Operating Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.80%
Minimum [Member] | Revolving Term Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.80%
Minimum [Member] | Heron Lake Bioenergy [Member] | Revolving Term Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	3.50%
Maximum [Member] | Revolving Operating Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	3.05%
Maximum [Member] | Revolving Term Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	3.05%
Maximum [Member] | Heron Lake Bioenergy [Member] | Revolving Term Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	5.00%
Convertible Subordinated Debt [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate During Period	7.25%
Common Class A [Member] | Convertible Subordinated Debt [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Convertible, Conversion Price	0.30
Debt Conversion, Converted Instrument, Amount	934,500
Conversion of Stock, Shares Converted	3,115,000