2.4.0.82201201 - Disclosure - Summary of Significant Accounting Policies Level 2 (Policies)truefalsefalse1false falsefalseD2013Q3YTDhttp://www.sec.gov/CIK0001181749duration2012-11-01T00:00:002013-07-31T00:00:001true 1us-gaap_AccountingPoliciesAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Accounting Policies [Abstract]2false 2us-gaap_BasisOfAccountingPolicyPolicyTextBlockus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;">Basis of Presentation and Principles of Consolidation</font><font style="font-family:inherit;font-size:10pt;font-style:italic;"> </font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The accompanying financial statements consolidate the operating results and financial position of Granite Falls Energy, LLC (“GFE” or the “Company”), and its wholly owned subsidiary, Project Viking, L.L.C. ("Project Viking") which owns 63.3% of Heron Lake BioEnergy, LLC (“HLBE”). The remaining 36.7% ownership of HLBE is included in the consolidated financial statements as a non-controlling interest. All intercompany balances and transactions are eliminated in consolidation. See Note 3 for details of acquisition.</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The accompanying condensed consolidated balance sheet as of October 31, 2012 is derived from audited financial statements. The unaudited interim condensed consolidated financial statements of the Company reflect all adjustments consisting only of normal recurring adjustments that are, in the opinion of management, necessary for a fair presentation of financial position and results of operations and cash flows. The results for the three and nine month periods ended July 31, 2013 are not necessarily indicative of the results that may be expected for a full fiscal year. Certain information and note disclosures normally included in annual consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) are condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”), although the Company believes that the disclosures made are adequate to make the information not misleading. These condensed consolidated financial statements should be read in conjunction with the Company's audited financial statements and notes thereto included in its annual report for the year ended October 31, 2012 filed on Form 10-K with the SEC. </font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></div>falsefalsefalsenonnum:textBlockItemTypenaDisclosure of accounting policy for basis of accounting, or basis of presentation, used to prepare the financial statements (for example, US Generally Accepted Accounting Principles, Other Comprehensive Basis of Accounting, IFRS).No definition available.false0Basis of Presentation and Significant Accounting Policies [Text Block]3false 2gfe_NatureOfBusinessPolicyTextBlockgfe_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;">Nature of Business</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">GFE is a Minnesota limited liability company currently producing fuel-grade ethanol, distillers grains, and crude corn oil near Granite Falls, Minnesota and sells these products, pursuant to marketing agreements, throughout the continental United States. GFE's plant has an approximate annual production capacity of </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">60 million</font><font style="font-family:inherit;font-size:10pt;"> gallons, but is currently permitted to produce up to </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">70 million</font><font style="font-family:inherit;font-size:10pt;"> gallons of undenatured ethanol on a </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">twelve</font><font style="font-family:inherit;font-size:10pt;"> month rolling sum basis.</font></div><div style="line-height:120%;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">HLBE is a Minnesota limited liability company currently producing fuel-grade ethanol, distillers grains, and crude corn oil near Heron Lake, Minnesota and sells these products, pursuant to marketing agreements, throughout the continental United States. HLBE's plant has an approximate annual production capacity of </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">50 million</font><font style="font-family:inherit;font-size:10pt;"> gallons, but is currently permitted to produce up to </font><font style="font-family:inherit;font-size:10pt;">59.2 million</font><font style="font-family:inherit;font-size:10pt;"> gallons.</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></div>falsefalsefalsenonnum:textBlockItemTypenaNature of Business [Policy Text Block]No definition available.false0Nature of Operations [Text Block]4false 2us-gaap_UseOfEstimatesus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;">Accounting Estimates</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Management uses estimates and assumptions in preparing these condensed consolidated financial statements in accordance with generally accepted accounting principles in the United States of America. Those estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the reported revenues and expenses. The Company uses estimates and assumptions in accounting for the following significant matters, among others: economic lives of property, plant, and equipment, valuation of commodity derivatives and inventory, the assumptions used in the impairment analysis of long-lived assets, and the assumptions used to estimate the fair market value of acquired assets and liabilities. Actual results may differ from previously estimated amounts, and such differences may be material to our condensed consolidated financial statements. The Company periodically reviews estimates and assumptions, and the effects of revisions are reflected in the period in which the revision is made.</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></div>falsefalsefalsenonnum:textBlockItemTypenaDisclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6143-108592 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6132-108592 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6061-108592 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 94-6 -Paragraph 11, 14 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Use of Estimates, Policy [Policy Text Block]5false 2us-gaap_RevenueRecognitionPolicyTextBlockus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;">Revenue Recognition</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The Company generally sells ethanol and related products pursuant to marketing agreements. Revenues from the production of ethanol and the related products are recorded when the customer has taken title and assumed the risks and rewards of ownership, prices are fixed or determinable and collectability is reasonably assured. Ethanol and related products are generally shipped free on board (FOB) shipping point. The Company believes there are no ethanol sales, during any given month, which should be considered contingent and recorded as deferred revenue. </font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">In accordance with the Company's agreements for the marketing and sale of ethanol and related products, marketing fees and commissions due to the marketers are deducted from the gross sales price as earned. These fees and commissions are recorded net of revenues, as they do not provide an identifiable benefit that is sufficiently separable from the sale of ethanol and related products. Shipping costs paid by the Company to the marketer in the sale of ethanol are not specifically identifiable and, as a result, are recorded based on the net selling price reported to the Company from the marketer. Shipping costs incurred by the Company in the sale of distillers grains and corn oil are included in cost of goods sold.</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></div>falsefalsefalsenonnum:textBlockItemTypenaDisclosure of accounting policy for revenue recognition. If the entity has different policies for different types of revenue transactions, the policy for each material type of transaction is generally disclosed. If a sales transaction has multiple element arrangements (for example, delivery of multiple products, services or the rights to use assets) the disclosure may indicate the accounting policy for each unit of accounting as well as how units of accounting are determined and valued. The disclosure may encompass important judgment as to appropriateness of principles related to recognition of revenue. The disclosure also may indicate the entity's treatment of any unearned or deferred revenue that arises from the transaction.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18726-107790 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 13 -Section B -Paragraph Question 1 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 605 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 13.B.Q1) -URI http://asc.fasb.org/extlink&oid=6600647&loc=d3e214044-122780 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 22 -Paragraph 8, 12, 13 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18823-107790 false0Revenue Recognition, Policy [Policy Text Block]6false 2us-gaap_DerivativesPolicyTextBlockus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;">Derivative Instruments</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">From time to time the Company enters into derivative transactions to hedge its exposures to commodity price fluctuations. The Company is required to record these derivatives in the balance sheets at fair value. </font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">In order for a derivative to qualify as a hedge, specific criteria must be met and appropriate documentation maintained. Gains and losses from derivatives that do not qualify as hedges, or are undesignated, must be recognized immediately in earnings. If the derivative does qualify as a hedge, depending on the nature of the hedge, changes in the fair value of the derivative will be either offset against the change in fair value of the hedged assets, liabilities, or firm commitments through earnings or recognized in other comprehensive income until the hedged item is recognized in earnings. Changes in the fair value of undesignated derivatives are recorded in earnings. </font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Additionally, the Company is required to evaluate its contracts to determine whether the contracts are derivatives. Certain contracts that literally meet the definition of a derivative may be exempted as “normal purchases or normal sales”. Normal purchases and normal sales are contracts that provide for the purchase or sale of something other than a financial instrument or derivative instrument that will be delivered in quantities expected to be used or sold over a reasonable period in the normal course of business. Contracts that meet the requirements of normal purchases or sales are documented as normal and exempted from accounting and reporting requirements, and therefore, are not marked to market in our condensed consolidated financial statements.</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">In order to reduce the risks caused by market fluctuations, the Company occasionally hedges its anticipated corn, natural gas, and denaturant purchases and ethanol sales by entering into options and futures contracts. These contracts are used with the intention to fix the purchase price of anticipated requirements for corn in the Company's ethanol production activities and the related sales price of ethanol. The fair value of these contracts is based on quoted prices in active exchange-traded or over-the-counter market conditions. Although the Company believes its commodity derivative positions are economic hedges, none have been formally designated as a hedge for accounting purposes and derivative positions are recorded on the balance sheet at their fair market value, with changes in fair value recognized in current period earnings or losses. The Company does not enter into financial instruments for trading or speculative purposes.</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The Company has adopted authoritative guidance related to “Derivatives and Hedging,” and has included the required enhanced quantitative and qualitative disclosure about objectives and strategies for using derivatives, quantitative disclosures about fair value amounts of gains and losses from derivative instruments, and disclosures about credit-risk-related contingent features in derivative agreements. See further discussion in Note 5.</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></div>falsefalsefalsenonnum:textBlockItemTypenaDisclosure of accounting policy for its derivative instruments and hedging activities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph n -Article 4 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41620-113959 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579245-113959 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579240-113959 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41638-113959 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(n)) -URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41675-113959 Reference 10: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Interpretation (FIN) -Number 39 -Paragraph 10 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Derivatives, Policy [Policy Text Block]7false 2us-gaap_BusinessCombinationsPolicyus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;">Business Combinations</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The Company allocates the total purchase price of a business combination to the assets acquired and the liabilities assumed based on their estimated fair values at the acquisition date, with the excess purchase price recorded as goodwill. The Company used current market data to assist them in determining the fair value of the assets acquired and liabilities assumed, including goodwill, based on recognized business valuation methodology. Subsequent to the acquisition but not to exceed one year from the acquisition date, the Company will record any material adjustments retrospectively to the initial estimate based on new information obtained about facts and circumstances that existed as of the acquisition date. The Company expenses any acquisition-related costs as incurred in connection with business combinations. An income, market or cost valuation method may be utilized to estimate the fair value of the assets acquired or liabilities assumed in a business combination. The income valuation method represents the present value of future cash flows over the life of the asset using (i) discrete financial forecasts, which rely on management's estimates of revenue and operating expenses, (ii) long-term growth rates, and (iii) an appropriate discount rate. The market valuation method uses prices paid for a reasonably similar asset by other purchasers in the market, with adjustments relating to any differences between the assets. The cost valuation method is based on the replacement cost of a comparable asset at prices at the time of the acquisition reduced for depreciation of the asset.</font></div></div>falsefalsefalsenonnum:textBlockItemTypenaDisclosure of accounting policy for completed business combinations (purchase method, acquisition method or combination of entities under common control). This accounting policy may include a general discussion of the purchase method or acquisition method of accounting (including for example, the treatment accorded contingent consideration, the identification of assets and liabilities, the purchase price allocation process, how the fair values of acquired assets and liabilities are determined) and the entity's specific application thereof. An entity that acquires another entity in a leveraged buyout transaction generally discloses the accounting policy followed by the acquiring entity in determining the basis used to value its interest in the acquired entity, and the rationale for that accounting policy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -URI http://asc.fasb.org/subtopic&trid=2303973 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 05 -Paragraph 4 -Subparagraph (a)-(d) -URI http://asc.fasb.org/extlink&oid=6909625&loc=d3e227-128457 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 6 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 7 -Subparagraph a, b, c, d -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 88-16 -Section SEC Observer Comments -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 9, 10, 11, 12, 13 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Business Combinations Policy [Policy Text Block]8false 2us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicyus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;">Goodwill</font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Goodwill represents the cost in excess of the fair value of net assets acquired. The Company will conduct impairment assessments annually or when events indicate a triggering event has occurred.</font></div></div>falsefalsefalsenonnum:textBlockItemTypenaDisclosure of accounting policy for goodwill. This accounting policy also may address how an entity assesses and measures impairment of goodwill, how reporting units are determined, how goodwill is allocated to such units, and how the fair values of the reporting units are determined.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -URI http://asc.fasb.org/subtopic&trid=2144439 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 142 -Paragraph 18-23, 26, 34 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]falseSummary of Significant Accounting Policies Level 2 (Policies)UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.granitefallsenergy.com/role/SummaryOfSignificantAccountingPoliciesLevel2Policies18