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Disclosure - Note 6 - Derivative Instruments (Tables) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-6-derivative-instruments-tables Note 6 - Derivative Instruments (Tables) Tables http://www.futurefuelcorporation.com/20191231/role/statement-note-6-derivative-instruments 35 false false R36.htm 035 - Disclosure - Note 7 - Marketable Securities (Tables) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-7-marketable-securities-tables Note 7 - Marketable Securities (Tables) Tables http://www.futurefuelcorporation.com/20191231/role/statement-note-7-marketable-securities 36 false false R37.htm 036 - Disclosure - Note 9 - Property, Plant, and Equipment (Tables) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-9-property-plant-and-equipment-tables Note 9 - Property, Plant, and Equipment (Tables) Tables http://www.futurefuelcorporation.com/20191231/role/statement-note-9-property-plant-and-equipment 37 false false R38.htm 037 - Disclosure - Note 12 - Accrued Expenses and Other Current Liabilities (Tables) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-12-accrued-expenses-and-other-current-liabilities-tables Note 12 - Accrued Expenses and Other Current Liabilities (Tables) Tables http://www.futurefuelcorporation.com/20191231/role/statement-note-12-accrued-expenses-and-other-current-liabilities 38 false false R39.htm 038 - Disclosure - Note 13 - Borrowings (Tables) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-13-borrowings-tables Note 13 - Borrowings (Tables) Tables http://www.futurefuelcorporation.com/20191231/role/statement-note-13-borrowings 39 false false R40.htm 039 - Disclosure - Note 15 - Lease Commitments and Purchase Obligations (Tables) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-15-lease-commitments-and-purchase-obligations-tables Note 15 - Lease Commitments and Purchase Obligations (Tables) Tables http://www.futurefuelcorporation.com/20191231/role/statement-note-15-lease-commitments-and-purchase-obligations 40 false false R41.htm 040 - Disclosure - Note 16 - Income Tax (Benefit) Provision (Tables) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-16-income-tax-benefit-provision-tables Note 16 - Income Tax (Benefit) Provision (Tables) Tables http://www.futurefuelcorporation.com/20191231/role/statement-note-16-income-tax-benefit-provision 41 false false R42.htm 041 - Disclosure - Note 17 - Earnings Per Share (Tables) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-17-earnings-per-share-tables Note 17 - Earnings Per Share (Tables) Tables http://www.futurefuelcorporation.com/20191231/role/statement-note-17-earnings-per-share 42 false false R43.htm 042 - Disclosure - Note 18 - Stock Based Compensation (Tables) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-18-stock-based-compensation-tables Note 18 - Stock Based Compensation (Tables) Tables http://www.futurefuelcorporation.com/20191231/role/statement-note-18-stock-based-compensation 43 false false R44.htm 043 - Disclosure - Note 21 - Related Party Transactions (Tables) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-21-related-party-transactions-tables Note 21 - Related Party Transactions (Tables) Tables http://www.futurefuelcorporation.com/20191231/role/statement-note-21-related-party-transactions 44 false false R45.htm 044 - Disclosure - Note 22 - Segment Information (Tables) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-22-segment-information-tables Note 22 - Segment Information (Tables) Tables http://www.futurefuelcorporation.com/20191231/role/statement-note-22-segment-information 45 false false R46.htm 045 - Disclosure - Note 23 - Quarterly Financial Information (Unaudited) (Tables) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-23-quarterly-financial-information-unaudited-tables Note 23 - Quarterly Financial Information (Unaudited) (Tables) Tables http://www.futurefuelcorporation.com/20191231/role/statement-note-23-quarterly-financial-information-unaudited 46 false false R47.htm 046 - Disclosure - Note 2 - Significant Accounting Policies and Basis of Presentation (Details Textual) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-2-significant-accounting-policies-and-basis-of-presentation-details-textual Note 2 - Significant Accounting Policies and Basis of Presentation (Details Textual) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-2-significant-accounting-policies-and-basis-of-presentation-tables 47 false false R48.htm 047 - Disclosure - Note 2 - Significant Accounting Policies - Estimated Useful Lives of Property, Plant, and Equipment (Details) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-2-significant-accounting-policies-estimated-useful-lives-of-property-plant-and-equipment-details Note 2 - Significant Accounting Policies - Estimated Useful Lives of Property, Plant, and Equipment (Details) Details 48 false false R49.htm 048 - Disclosure - Note 3 - Reinstatement of the Biodiesel Blenders' Tax Credit and Small Agri-biodiesel Producer Tax Credit (Details Textual) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-3-reinstatement-of-the-biodiesel-blenders-tax-credit-and-small-agribiodiesel-producer-tax-credit-details-textual Note 3 - 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Disclosure - Note 5 - Inventory (Details Textual) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-5-inventory-details-textual Note 5 - Inventory (Details Textual) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-5-inventory-tables 55 false false R56.htm 055 - Disclosure - Note 5 - Inventory - Carrying Values of Inventory (Details) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-5-inventory-carrying-values-of-inventory-details Note 5 - Inventory - Carrying Values of Inventory (Details) Details 56 false false R57.htm 056 - Disclosure - Note 6 - Derivative Instruments (Details Textual) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-6-derivative-instruments-details-textual Note 6 - Derivative Instruments (Details Textual) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-6-derivative-instruments-tables 57 false false R58.htm 057 - Disclosure - Note 6 - Derivative Instruments - 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Disclosure - Note 13 - Borrowings - Leverage Ratio (Details) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-13-borrowings-leverage-ratio-details Note 13 - Borrowings - Leverage Ratio (Details) Details 67 false false R68.htm 067 - Disclosure - Note 14 - Asset Retirement Obligations and Environmental Reserves (Details Textual) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-14-asset-retirement-obligations-and-environmental-reserves-details-textual Note 14 - Asset Retirement Obligations and Environmental Reserves (Details Textual) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-14-asset-retirement-obligations-and-environmental-reserves 68 false false R69.htm 068 - Disclosure - Note 15 - Lease Commitments and Purchase Obligations (Details Textual) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-15-lease-commitments-and-purchase-obligations-details-textual Note 15 - Lease Commitments and Purchase Obligations (Details Textual) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-15-lease-commitments-and-purchase-obligations-tables 69 false false R70.htm 069 - Disclosure - Note 15 - Lease Commitments and Purchase Obligations - Lease Cost (Details) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-15-lease-commitments-and-purchase-obligations-lease-cost-details Note 15 - Lease Commitments and Purchase Obligations - Lease Cost (Details) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-15-lease-commitments-and-purchase-obligations-tables 70 false false R71.htm 070 - Disclosure - Note 15 - Lease Commitments and Purchase Obligations - Maturities of Lease Liabilities (Details) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-15-lease-commitments-and-purchase-obligations-maturities-of-lease-liabilities-details Note 15 - Lease Commitments and Purchase Obligations - Maturities of Lease Liabilities (Details) Details 71 false false R72.htm 071 - Disclosure - Note 15 - Lease Commitments and Purchase Obligations - Payment Obligations (Details) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-15-lease-commitments-and-purchase-obligations-payment-obligations-details Note 15 - Lease Commitments and Purchase Obligations - Payment Obligations (Details) Details 72 false false R73.htm 072 - Disclosure - Note 16 - Income Tax (Benefit) Provision (Details Textual) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-16-income-tax-benefit-provision-details-textual Note 16 - Income Tax (Benefit) Provision (Details Textual) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-16-income-tax-benefit-provision-tables 73 false false R74.htm 073 - Disclosure - Note 16 - Income Tax (Benefit) Provision - Summary of Provisions for Income Taxes (Details) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-16-income-tax-benefit-provision-summary-of-provisions-for-income-taxes-details Note 16 - Income Tax (Benefit) Provision - Summary of Provisions for Income Taxes (Details) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-16-income-tax-benefit-provision-tables 74 false false R75.htm 074 - Disclosure - Note 16 - Income Tax (Benefit) Provision - Effective Income Tax Rate Reconciliation (Details) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-16-income-tax-benefit-provision-effective-income-tax-rate-reconciliation-details Note 16 - Income Tax (Benefit) Provision - Effective Income Tax Rate Reconciliation (Details) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-16-income-tax-benefit-provision-tables 75 false false R76.htm 075 - Disclosure - Note 16 - Income Tax (Benefit) Provision - Components of Deferred Tax Assets and Liabilities (Details) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-16-income-tax-benefit-provision-components-of-deferred-tax-assets-and-liabilities-details Note 16 - Income Tax (Benefit) Provision - Components of Deferred Tax Assets and Liabilities (Details) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-16-income-tax-benefit-provision-tables 76 false false R77.htm 076 - Disclosure - Note 16 - Income Tax (Benefit) Provision - Unrecognized Tax Benefits Activity (Details) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-16-income-tax-benefit-provision-unrecognized-tax-benefits-activity-details Note 16 - Income Tax (Benefit) Provision - Unrecognized Tax Benefits Activity (Details) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-16-income-tax-benefit-provision-tables 77 false false R78.htm 077 - Disclosure - Note 17 - Earnings Per Share (Details Textual) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-17-earnings-per-share-details-textual Note 17 - Earnings Per Share (Details Textual) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-17-earnings-per-share-tables 78 false false R79.htm 078 - Disclosure - Note 17 - Earnings Per Share - Computation of Basic and Diluted Earnings Per Common Share (Details) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-17-earnings-per-share-computation-of-basic-and-diluted-earnings-per-common-share-details Note 17 - Earnings Per Share - Computation of Basic and Diluted Earnings Per Common Share (Details) Details 79 false false R80.htm 079 - Disclosure - Note 18 - Stock Based Compensation (Details Textual) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-18-stock-based-compensation-details-textual Note 18 - Stock Based Compensation (Details Textual) Details http://www.futurefuelcorporation.com/20191231/role/statement-note-18-stock-based-compensation-tables 80 false false R81.htm 080 - Disclosure - Note 18 - Stock Based Compensation - Assumptions Used in the Determination of the Fair Value of the Options Granted (Details) Sheet http://www.futurefuelcorporation.com/20191231/role/statement-note-18-stock-based-compensation-assumptions-used-in-the-determination-of-the-fair-value-of-the-options-granted-details Note 18 - Stock Based Compensation - Assumptions Used in the Determination of the Fair Value of the Options Granted (Details) Details 81 false false R82.htm 081 - Disclosure - 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