Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] Maximum Maximum [Member] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Statistical Measurement [Domain] Statistical Measurement [Domain] Title of 12(b) Security Title of 12(b) Security Document Fiscal Year Focus Document Fiscal Year Focus Adjustment to Compensation, Amount Adjustment to Compensation Amount Customer [Axis] Customer [Axis] Segment Reporting [Abstract] Segment Reporting [Abstract] Common stock, par value $1.00 per share, 200,000,000 authorized shares, 51,008,733 and 50,833,171 shares issued and outstanding at June 30, 2026 and September 30, 2025, respectively Common Stock, Value, Issued Cash paid for shares withheld for taxes Payment, Tax Withholding, Share-Based Payment Arrangement Revenue from External Customers by Products and Services [Table] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Table] Schedule of Long-term Debt Instruments Schedule of Long-Term Debt Instruments [Table Text Block] Inventory, Interest Capitalization Policy [Table Text Block] Inventory, Interest Capitalization Policy [Table Text Block] Inventory, Interest Capitalization Policy [Table Text Block] Legal Settlement, Funds Contributed to Trust Legal Settlement, Funds Contributed to Trust Legal Settlement, Funds Contributed to Trust Restatement Determination Date Restatement Determination Date Accrued employee compensation and benefits Employee-related Liabilities Amendment Flag Amendment Flag Inventory [Axis] Inventory [Axis] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Debt Instrument, Maturity Date Debt Instrument, Maturity Date Deferred income taxes Increase (Decrease) in Deferred Income Taxes Related Party Transactions Disclosure [Text Block] Related Party Transactions Disclosure [Text Block] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Bond Reimbursement Receivable Bond Reimbursement Receivable Bond Reimbursement Receivable Entity Address, State or Province Entity Address, State or Province PEO Total Compensation Amount PEO Total Compensation Amount Common stock, par value (in usd per share) Common Stock, Par or Stated Value Per Share Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Exchange [Domain] Exchange [Domain] Decrease in accrued development costs Increase (Decrease) in Accrued Liabilities and Other Operating Liabilities Weighted average number of common shares Weighted Average Number of Shares Outstanding, Basic Related Party Transaction, Purchases from Related Party Related Party Transaction, Purchases from Related Party Schedule of Related Party Transactions [Table Text Block] Schedule of Related Party Transactions [Table Text Block] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Other Preacquisition and Due Diligence Costs [Member] Other Preacquisition and Due Diligence Costs [Member] Other Preacquisition and Due Diligence Costs Interest and other income Interest and Other Income Residential lot sales Residential lot sales Revenue from Contract with Customer, Including Assessed Tax Entity Address, City or Town Entity Address, City or Town Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Income taxes payable Taxes Payable Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Title of Individual [Domain] Title and Position [Domain] Use Rights Use Rights [Member] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Basis of Accounting, Policy [Policy Text Block] Basis of Accounting, Policy [Policy Text Block] Class of Stock [Axis] Class of Stock [Axis] Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Return of investment in unconsolidated ventures Proceeds from Equity Method Investment, Distribution, Return of Capital Level 2 Fair Value, Inputs, Level 2 [Member] Credit Facility Maturing December 18, 2029 Credit Facility Maturing December 18, 2029 [Member] Credit Facility Maturing December 18, 2029 Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Equity Securities Registered, Value Equity Securities Registered, Value The dollar amount of equity securities registered under the entity's registration statement. Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] New Accounting Pronouncements, Policy [Policy Text Block] New Accounting Pronouncements, Policy [Policy Text Block] Land held for future development Land [Member] Increase in earnest money deposits on sales contracts Increase (Decrease) in Contract with Customer, Liability Noncontrolling Interest Noncontrolling Interest [Member] Use of Estimates, Policy [Policy Text Block] Use of Estimates, Policy [Policy Text Block] Related Party, Type [Axis] Related and Nonrelated Parties [Axis] Debt Instrument, Redemption, Period Two Debt Instrument, Redemption, Period Two [Member] Debt Long-Term Debt Related Party Transaction, Rate Related Party Transaction, Rate Document Period End Date Document Period End Date Changes in operating assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Schedule of Other Assets and Liabilities [Table] Schedule of Other Assets and Liabilities [Table] Schedule of Other Assets and Liabilities Net cash used in investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Debt Instrument, Face Amount Debt Instrument, Face Amount Credit Facility Maturing October 28, 2026 Credit Facility Maturing October 28, 2026 [Member] Credit Facility Maturing October 28, 2026 Stockholders' Equity Note Disclosure [Text Block] Equity [Text Block] Security Exchange Name Security Exchange Name Debt Instrument, Interest Rate, Effective Percentage Debt Instrument, Interest Rate, Effective Percentage Right of First Offer [Member] Right of First Offer [Member] Right of First Offer [Member] Under Contract [Member] Under Contract [Member] Under Contract [Member] Entity Shell Company Entity Shell Company Real Estate Schedule of Real Estate Properties [Table Text Block] Fair Value, by Balance Sheet Grouping [Table Text Block] Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block] Earnings Per Share Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Earnings Per Share [Abstract] Earnings Per Share [Abstract] Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Document Fiscal Period Focus Document Fiscal Period Focus Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items] Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Table Text Block] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Table Text Block] Total liabilities Liabilities Trading Symbol Trading Symbol Accrued property taxes Accrual for Taxes Other than Income Taxes Expenditures for property, equipment, software and other Payments to Acquire Property, Plant, and Equipment Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Company Selected Measure Name Company Selected Measure Name Number of Lots Sold Number of Lots Sold Number of Lots Sold Transaction [Domain] Transaction [Domain] Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Award Date [Axis] Award Date [Axis] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Credit Facility [Domain] Credit Facility [Domain] Related Party Transactions [Abstract] Related Party Transactions [Abstract] OPERATING ACTIVITIES Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Payments to Acquire Residential Real Estate Payments to Acquire Residential Real Estate Compensation Amount Outstanding Recovery Compensation Amount Individual: Individual [Axis] Adjusted weighted average number of common shares Weighted Average Number of Shares Outstanding, Diluted Entity Emerging Growth Company Entity Emerging Growth Company Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Pledged reimbursements liability Bond Reimbursement Nonrecourse Liability Bond Reimbursement Nonrecourse Liability Entities [Table] Entities [Table] Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage Award Date [Domain] Award Date [Domain] Operating Lease, Liability, Statement of Financial Position [Extensible List] Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration] Prepaid expenses Prepaid Expense Line of Credit Facility, Current Borrowing Capacity Line of Credit Facility, Current Borrowing Capacity Receivables, net Other Receivables Award Timing Predetermined Award Timing Predetermined [Flag] Letters of Credit Outstanding, Amount Letters of Credit Outstanding, Amount Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] APIC, Share-Based Payment Arrangement, Increase for Cost Recognition APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Level 1 Fair Value, Inputs, Level 1 [Member] Other assets Other Assets, Miscellaneous Effective Income Tax Rate Reconciliation, Percent Effective Income Tax Rate Reconciliation, Percent Organization, Consolidation and Presentation of Financial Statements [Abstract] Dilutive effect of stock-based compensation Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements All Executive Categories All Executive Categories [Member] Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Long-term Debt, Fair Value Long-Term Debt, Fair Value Lease right of use assets Operating Lease, Right-of-Use Asset Legal Fees Legal Fees Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Segment Information Segment Reporting [Text Block] Long-term Line of Credit Long-Term Line of Credit Minimum Minimum [Member] Expiration Date Trading Arrangement Expiration Date Related Party Transaction, Purchase Obligation from Parent Related Party Transaction, Purchase Obligation from Parent Related Party Transaction, Purchase Obligation from Parent Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Cash and Cash Equivalents, Fair Value Disclosure Cash and Cash Equivalents, Fair Value Disclosure Total equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance Equity, Including Portion Attributable to Noncontrolling Interest D.R. Horton, Inc. [Member] D.R. Horton, Inc. [Member] D.R. Horton, Inc. [Member] Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Schedule of Real Estate Properties [Table] Real Estate Property, Ownership [Table] Other liabilities Other Liabilities Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Letter of Credit, Maximum Borrowing Capacity, Percentage of Revolving Credit Commitment Letter of Credit, Maximum Borrowing Capacity, Percentage of Revolving Credit Commitment Letter of Credit, Maximum Borrowing Capacity, Percentage of Revolving Credit Commitment Sale of Stock, Percentage of Ownership after Transaction Sale of Stock, Percentage of Ownership after Transaction Common Stock, Shares Authorized Common Stock, Shares Authorized Number of Units in Real Estate Property Number of Units in Real Estate Property Loss on Contract Termination Loss on Contract Termination Exercise Price Award Exercise Price INVESTING ACTIVITIES Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Document Quarterly Report Document Quarterly Report Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Debt Instrument, Redemption Period, End Date Debt Instrument, Redemption Period, End Date Lender Name [Axis] Lender Name [Axis] Debt Debt Disclosure [Text Block] Deposits [Member] Deposits [Member] Accrued interest Interest Payable Debt Issuance Costs, Net Debt Issuance Costs, Net Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Real Estate Real Estate Disclosure [Text Block] Interest incurred Interest Costs Incurred Equity Component [Domain] Equity Component [Domain] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Secured Debt Secured Debt [Member] Adoption Date Trading Arrangement Adoption Date Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Counterparty Name [Domain] Counterparty Name [Domain] Stockholders' equity Equity, Attributable to Parent Document Document And Entity Information [Abstract] Document Document And Entity Information [Abstract] Document Document and Entity Information [Abstract] Entity Listings, Exchange [Axis] Entity Listings, Exchange [Axis] Real Estate [Domain] Real Estate [Domain] ASSETS Assets [Abstract] Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Accrued development costs Accrued Development Costs Accrued Development Costs Deferred Revenue, Period Increase (Decrease) Deferred Revenue, Period Increase (Decrease) Accounting Policies [Abstract] Accounting Policies [Abstract] Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Lease liabilities Operating Lease, Liability Professional Fees Professional Fees Insider Trading Policies and Procedures [Line Items] Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Performance Shares Performance Shares [Member] Selling, general and administrative expense Selling, General and Administrative Expense Repayment of debt Repayments of Debt Commitments and Other Contingencies Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Entity Central Index Key Entity Central Index Key Additional paid-in capital Additional Paid in Capital, Common Stock All Adjustments to Compensation All Adjustments to Compensation [Member] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Net cash provided by (used in) operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Special Assessment Bond Special Assessment Bond Income Statement [Abstract] Income Statement [Abstract] Forestar Group Inc. shareholders’ equity: Equity, Attributable to Parent [Abstract] Document Transition Report Document Transition Report Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] City Area Code City Area Code Debt Instrument, Redemption, Period One Debt Instrument, Redemption, Period One [Member] Costs and Expenses, Related Party Costs and Expenses, Related Party All Individuals All Individuals [Member] Name Forgone Recovery, Individual Name Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Statement [Line Items] Statement [Line Items] Total assets Assets Capitalized Interest Capitalized Interest [Text Block] Capitalized Interest Employee Benefits and Share-Based Compensation Employee Benefits and Share-Based Compensation Statement [Line Items] Capitalized Interest [Line Items] Capitalized Interest Stock issued under employee benefit plans Proceeds, Issuance of Shares, Share-Based Payment Arrangement, Excluding Option Exercised Decrease (increase) in other assets Increase (Decrease) in Other Operating Assets PEO PEO [Member] NEW YORK STOCK EXCHANGE, INC. NEW YORK STOCK EXCHANGE, INC. [Member] Measurement Basis [Axis] Measurement Basis [Axis] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Developed and under development projects Land and Land Improvements [Member] Retained Earnings Retained Earnings [Member] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Common Stock, Shares, Outstanding Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Debt Repurchase Authorization Remaining Debt Repurchase Authorization Remaining Debt Repurchase Authorization Remaining Diluted net income per common share Earnings Per Share, Diluted Capitalized Interest [Axis] Capitalized Interest [Axis] Capitalized Interest Entity Current Reporting Status Entity Current Reporting Status Net cash (used in) provided by financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation Inventory [Domain] Inventory [Domain] Adjustments: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] FINANCING ACTIVITIES Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Property and equipment, net Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization Line of Credit Facility, Remaining Borrowing Capacity Line of Credit Facility, Remaining Borrowing Capacity Real Estate Inventory, Capitalized Interest Costs Real Estate Inventory, Capitalized Interest Costs Tract sales and other Tract sales and other Other Revenue (Expense) from Real Estate Operations Debt Instrument, Redemption Price, Maximum Percentage of Principal Amount Redeemed Debt Instrument, Redemption Price, Maximum Percentage of Principal Amount Redeemed Debt Instrument, Redemption Price, Maximum Percentage of Principal Amount Able to Be Redeemed Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Underlying Securities Award Underlying Securities Amount Estimate of Fair Value Measurement Estimate of Fair Value Measurement [Member] Revenue from Contract with Customer [Text Block] Revenue from Contract with Customer [Text Block] Real estate Inventory, Real Estate, Land and Land Development Costs Increase in real estate Increase (Decrease) in Inventories Loss on extinguishment of debt Gain (Loss) on Repurchase of Debt Instrument Other accrued expenses Other Accrued Liabilities Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Table] Title of Individual [Axis] Title and Position [Axis] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Current Fiscal Year End Date Current Fiscal Year End Date Additions to debt Proceeds from Issuance of Debt Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Impairments and land option charges Production Related Impairments or Charges Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Asset, Impairment Loss Asset, Impairment Loss Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Common Stock, Shares, Issued Common Stock, Shares, Issued Measure: Measure [Axis] Entity Information [Line Items] Entity Information [Line Items] Equity Components [Axis] Equity Components [Axis] Product and Service [Domain] Product and Service [Domain] Class of Stock [Line Items] Class of Stock [Line Items] Deferred Tax Assets, Valuation Allowance Deferred Tax Assets, Valuation Allowance Entity Interactive Data Current Entity Interactive Data Current Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] Net income attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Deferred tax liability, net Deferred Income Tax Liabilities, Net Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Entity Small Business Entity Small Business Termination Date Trading Arrangement Termination Date Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] Document Type Document Type Fair Value as of Grant Date Award Grant Date Fair Value Common Stock, Shares Authorized Common Stock Available for Issuance, Value Remaining Common Stock Available for Issuance, Value Remaining Debt Instrument, Redemption Price, Percentage Debt Instrument, Redemption Price, Percentage Significant Accounting Policies Significant Accounting Policies [Text Block] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Earnings Per Share, Basic, by Common Class, Including Two-Class Method [Table] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Arrangement Duration Trading Arrangement Duration Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Local Phone Number Local Phone Number Other Assets, Accrued Expenses and Other Liabilities [Abstract] Other Assets, Accrued Expenses and Other Liabilities [Abstract] Other Assets, Accrued Expenses and Other Liabilities [Abstract] Deferred Tax Liabilities, Gross Deferred Tax Liabilities, Gross Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Commitments and contingencies (Note 11) Commitments and Contingencies Revenues Revenues Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period [Domain] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Equity in earnings of unconsolidated ventures Income (Loss) from Equity Method Investments Decrease in accounts payable and other accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Senior Notes 5.0% [Member] Senior Notes 5.0% [Member] Senior Notes 5.0% Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Counterparty Name [Axis] Counterparty Name [Axis] LIABILITIES Liabilities and Equity [Abstract] Related Party Deposit Liabilities Related Party Deposit Liabilities Award Type [Domain] Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Fair Value Fair Value Disclosures [Text Block] NYSE TEXAS, INC. NYSE TEXAS, INC. [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Transaction Type [Axis] Transaction Type [Axis] PEO Name PEO Name Accrued Liabilities and Other Liabilities Accrued Liabilities and Other Liabilities Earnest money on sales contracts Contract with Customer, Liability Repayments of Secured Debt Repayments of Secured Debt Other assets Other Assets Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Beginning Balance Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Ending Balance Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Majority Shareholder [Member] Majority Shareholder [Member] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Debt Instrument [Axis] Debt Instrument [Axis] Stock-based compensation expense Share-Based Payment Arrangement, Noncash Expense Related Party Transaction, Amounts of Transaction Related Party Transaction, Amounts of Transaction Customer [Domain] Customer [Domain] At-the-market Equity Offering Program, Common Stock Available for Issuance At-the-market Equity Offering Program, Common Stock Available for Issuance At-the-market Equity Offering Program, Common Stock Available for Issuance Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Basic net income per common share Earnings Per Share, Basic Deferred income Deferred Revenue Contract liabilities Contract with Customer, Liability, Current Letter of Credit, Maximum Borrowing Capacity Letter of Credit, Maximum Borrowing Capacity Maximum borrowing capacity of letter of credit. Statistical Measurement [Axis] Statistical Measurement [Axis] Insider Trading Arrangements [Line Items] Payments to Develop Real Estate Assets Payments to Develop Real Estate Assets Award Type [Axis] Award Type [Axis] Deferred financing fees Payments of Financing Costs Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] First Quarter Two Thousand Twenty Six Grant First Quarter Two Thousand Twenty Six Grant [Member] First Quarter Two Thousand Twenty Six Grant Retained earnings Retained Earnings (Accumulated Deficit) Product and Service [Axis] Product and Service [Axis] Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Real Estate, Type of Property [Axis] Real Estate, Type of Property [Axis] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Senior Notes 6.50% Senior Notes 6.50% [Member] Senior Notes 6.50% Common Stock Common Stock [Member] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Equity Awards Adjustments Equity Awards Adjustments [Member] Other Assets And Other Liabilities [Text Block] Other Assets And Other Liabilities [Text Block] Other Assets and Other Liabilities [Text Block] Total liabilities and equity Liabilities and Equity Employee Stock Option Share-Based Payment Arrangement, Option [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Noncontrolling interests Equity, Attributable to Noncontrolling Interest Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Related Party [Domain] Related and Nonrelated Parties [Domain] Tabular List, Table Tabular List [Table Text Block] Land purchase contract deposits Deposits Assets Debt Repurchase Program, Authorized Amount Debt Repurchase Program, Authorized Amount Debt Repurchase Program, Authorized Amount Capitalized Interest [Domain] Capitalized Interest [Domain] Capitalized Interest Name Awards Close in Time to MNPI Disclosures, Individual Name Real Estate Properties [Line Items] Real Estate Properties [Line Items] EQUITY Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Schedule of Other Assets and Other Liabilities [Table Text Block] Schedule of Other Assets and Other Liabilities [Table Text Block] Adjustment to Compensation: Adjustment to Compensation [Axis] Class of Stock [Domain] Class of Stock [Domain] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Credit Facility [Axis] Credit Facility [Axis] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Retirement Eligible Retirement Eligible [Member] Retirement Eligible Debt Instrument, Frequency of Periodic Payment Debt Instrument, Frequency of Periodic Payment Accounts payable Accounts Payable Line of Credit Facility, Increase (Decrease), Net Line of Credit Facility, Increase (Decrease), Net Name Measure Name Income Taxes Income Tax Disclosure [Text Block] Pay vs Performance Disclosure [Line Items] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Debt Instrument [Line Items] Debt Instrument [Line Items] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Schedule of Other Assets, Accrued Expenses and Other Liabilities [Line Items] Schedule of Other Assets, Accrued Expenses and Other Liabilities [Line Items] Schedule of Other Assets, Accrued Expenses and Other Liabilities Additional Paid-in Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Accrued expenses and other liabilities Accrued Liabilities Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and Cash Equivalent Company Selected Measure Amount Company Selected Measure Amount Income taxes receivable Income Taxes Receivable Depreciation and amortization Depreciation, Depletion and Amortization Statement [Table] Capitalized Interest [Table] Capitalized Interest Interest charged to cost of sales Real Estate Inventory, Capitalized Interest Costs, Cost of Sales Entity Address, Address Line Two Entity Address, Address Line Two Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture Schedule of Stock by Class [Table] Stock, Class of Stock [Table] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Real Estate [Abstract] Real Estate [Abstract] Time-Based RSU Time-Based RSU [Member] Time-Based RSU Non-PEO NEO Non-PEO NEO [Member] Senior Notes [Member] Senior Notes [Member] Entity Address, Address Line One Entity Address, Address Line One Income tax expense Income Tax Expense (Benefit) Cost of sales Cost of Product and Service Sold Purchase Obligation Purchase Obligation Award Timing Method Award Timing Method [Text Block] Increase (decrease) in cash and cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Net income attributable to Forestar Group Inc. Net income Net Income (Loss) Attributable to Parent Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Statement [Table] Statement [Table] Restatement Determination Date: Restatement Determination Date [Axis] Revenues [Abstract] Revenues [Abstract] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Accounts Payable and Accrued Liabilities