Statement of Financial Position [Abstract] Cash and cash equivalents CASH AND CASH EQUIVALENTS-Beginning of year CASH AND CASH EQUIVALENTS-End of year Restricted cash Accounts receivable Accounts Receivable, Net, Current Inventory Total Refundable income taxes Prepaid expenses and other Deferred taxes - net Total current assets Current assets Property and equipment - net Total Other assets Total Equity method investments Total Equity Method Securities, Carrying Amount Equity Method Investments TOTAL ASSETS Total assets Accounts payable – trade Accrued expenses and other current liabilities Total Total current liabilities Current liabilities Deferred taxes Other long term liabilities Total long term liabilities Long-term liabilities Common stock, 45,000 shares authorized, 29,853 shares issued at par Common stock, shares authorized Authorized shares Common stock, shares issued Issued shares Paid in capital Retained earnings Treasury stock, 23,205 and 21,954 shares, respectively Treasury stock, shares Total REX shareholders’ equity Noncontrolling interests Total equity Balance Balance TOTAL LIABILITIES AND EQUITY Income Statement [Abstract] Net sales and revenue Cost of sales Gross profit Gross profit Selling, general and administrative expenses Gain on sale of investment Gain (Loss) on Sale of Investments Equity in income of unconsolidated ethanol affiliates Income from equity method investments Income (Loss) from Equity Method Investments Interest and other income Interest expense Gain (loss) on disposal of real estate and property and equipment, net Income from continuing operations before income taxes Provision for income taxes Provision for income taxes Income from continuing operations Income from discontinued operations, net of tax Income from discontinued operations, net of tax Gain on disposal of discontinued operations, net of tax Gain on disposal of discontinued operations, net of tax Net income Net income Net income Net income attributable to noncontrolling interests Net income attributable to REX common shareholders Net income Weighted average shares outstanding – basic (in Shares) Basic net income per share from continuing operations attributable to REX common shareholders Basic income per share from continuing operations attributable to REX common shareholders (in Dollars per share) Basic net income per share from continuing operations attributable to REX common shareholders (in Dollars per share) Basic income per share from discontinued operations attributable to REX common shareholders (in Dollars per share) Basic income per share on disposal of discontinued operations attributable to REX common shareholders (in Dollars per share) Basic net income per share attributable to REX common shareholders (in Dollars per share) Basic net income per share attributable to REX common shareholders (a) (in Dollars per share) Weighted average shares outstanding – diluted (in Shares) Diluted net income per share from continuing operations attributable to REX common shareholders Diluted income per share from continuing operations attributable to REX common shareholders (in Dollars per share) Diluted net income per share from continuing operations attributable to REX common shareholders (in Dollars per share) Diluted income per share from discontinued operations attributable to REX common shareholders (in Dollars per share) Diluted income per share on disposal of discontinued operations attributable to REX common shareholders (in Dollars per share) Diluted net income per share attributable to REX common shareholders (in Dollars per share) Diluted net income per share attributable to REX common shareholders (a) (in Dollars per share) Income from continuing operations, net of tax Income from discontinued operations, net of tax Statement of Stockholders' Equity [Abstract] Balance (in Shares) Balance (in Shares) Treasury stock acquired Treasury Stock, Value, Acquired, Cost Method (in Dollars) Treasury stock acquired (in Shares) Treasury Stock, Shares, Acquired Noncontrolling interests distribution and other Stock options and related tax effects Stock options and related tax effects (in Shares) Equity Components [Axis] Common Stock [Member] Treasury Stock [Member] Additional Paid-in Capital [Member] Retained Earnings [Member] Noncontrolling Interest [Member] Statement of Cash Flows [Abstract] Depreciation and amortization Impairment charges on real estate Impairment of Real Estate Stock based compensation expense Dividends received from equity method investments Gain on sale of investment Derivative financial instruments Gain on disposal of real estate and property and equipment Deferred income tax Excess tax benefit from stock option exercises Accounts receivable Inventory Prepaid expenses and other assets Income taxes refundable Accounts payable-trade Accrued expenses and other liabilities Net cash provided by operating activities Capital expenditures Repayment of note receivable Proceeds from sale of investment Proceeds from sale of real estate and property and equipment Restricted cash Restricted investments and deposits Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Payments of long term debt Stock options exercised Payments to noncontrolling interests holders Excess tax benefit from stock option exercises Treasury stock acquired Net cash used in financing activities NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS Non cash financing activities-Cashless exercises of stock options Non cash financing activities-Accrued common stock repurchase Non cash investing activities-Accrued capital expenditures Non cash investing activities- Loan receivable granted in connection with sale of real estate Accounting Policies [Abstract] Schedule of components of inventory [Abstract] Ethanol and other finished goods Work in process Grain and other raw materials Schedule of Property Plant and Equipment [Abstract] Land and improvements Buildings and improvements Machinery, equipment and fixtures Construction in progress Less: accumulated depreciation Investments And Deposits [Abstract] Schedule of Equity Method Investments [Abstract] Investment, Name [Axis] Big River [Member] Equity Method Securities, Ownership percentage Equity Method Investment, Ownership Percentage Patriot [Member] Schedule of Condensed Balance Sheet [Abstract] Total liabilities Legal Entity [Axis] Schedule of Financial information For Equity Method Investment [Abstract] Net sales and revenue Gross profit Income from continuing operations Net income Fair Value Disclosures [Abstract] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] Investment in cooperative Forward purchase contracts liability (2) Commodity futures (3) Total liabilities Liability Derivatives, Fair Value Fair Value, Hierarchy [Axis] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract] Balance Fair value adjustment Disclosure Text Block Supplement [Abstract] Schedule of Other Assets [Abstract] Schedule of accrued expenses and other current liabilities [Abstract] Earnings Per Share [Abstract] Schedule of Earnings Per Share, Basic and Diluted [Abstract] Leases [Abstract] Schedule of Future Minimum Rental Payments for Operating Leases [Abstract] Stockholders' Equity Note [Abstract] Schedule of Stock by Class [Abstract] Debt Disclosure [Abstract] Schedule of Fair Values for Derivative Financial Instruments [Abstract] Derivative Instrument [Axis] Commodity Contract [Member] Forward Contracts [Member] Schedule of Gains or Losses of Derivative Financial Instruments [Abstract] Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Schedule of Non-Vested Restricted Stock Award Activity [Abstract] Employee Stock Ownership Plan (ESOP) Name [Axis] Granted [Member] Forfeited [Member] Vested [Member] Schedule of Share-based Compensation, Stock Options, Activity [Abstract] Outstanding—Beginning of year Outstanding—End of year Outstanding—Beginning of year Outstanding—End of year Exercised Exercised Exercisable—End of year Exercisable—End of year