Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Andersen Aggregator LLC Andersen Aggregator LLC [Member] Andersen Aggregator LLC Amortized cost Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date [Abstract] Award Timing Predetermined Award Timing Predetermined [Flag] Indefinite-Lived Intangible Assets [Axis] Indefinite-Lived Intangible Assets [Axis] Investment in partnership Investment in partnership Deferred Tax Assets, Investment in Subsidiaries Entity File Number Entity File Number Additional Paid-in-Capital Additional Paid-in Capital [Member] Employee Legal Matters Employee Legal Matters [Member] Employee Legal Matters IPO IPO [Member] Deferred retirement obligations Postemployment Benefits Liability Tabular List, Table Tabular List [Table Text Block] Recently Issued Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Schedule of Related Party Transactions Schedule of Related Party Transactions [Table Text Block] Adjustment to Compensation: Adjustment to Compensation [Axis] Transactions with Related Parties Related Party Transactions Disclosure [Text Block] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Revenue Revenue from Contract with Customer [Text Block] Stock, Class of Stock [Table] Stock, Class of Stock [Table] Total current taxes Current Income Tax Expense (Benefit) Adjustment to Compensation, Amount Adjustment to Compensation Amount Andersen Group Inc Andersen Group Inc [Member] Andersen Group Inc Equity-based compensation Limited Liability Company (LLC) Members' Equity, Unit-Based Payment Arrangement Equity-based compensation Share-Based Payment Arrangement, Noncash Expense Investments in Held-to-Maturity Debt Securities Investments In Held to Maturity Debt Securities [Policy Text Block] Investments In Held to Maturity Debt Securities Employee Stock Option Share-Based Payment Arrangement, Option [Member] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Total loans and notes receivable from related parties, net of allowance for credit losses Total loans and notes receivable from related parties, net of allowance for credit losses Financing Receivable, after Allowance for Credit Loss Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Total stockholders' deficit/ members' equity Beginning balance Ending balance Equity, Attributable to Parent Measurement Frequency [Axis] Measurement Frequency [Axis] Insider Trading Policies and Procedures [Line Items] Schedule of Property and Equipment Schedule of Property and Equipment Property, Plant and Equipment [Table Text Block] Common stock authorized (in shares) Common Stock, Shares Authorized Deferred Compensation Arrangement with Individual, Excluding Share-Based Payment and Postretirement Benefit [Table] Deferred Compensation Arrangement with Individual, Excluding Share-Based Payment and Postretirement Benefit [Table] Issuance of common stock (in shares) Stock Issued During Period, Shares, New Issues Other current liabilities Increase (Decrease) in Other Current Liabilities Increase in deferred tax asset Adjustments to Additional Paid in Capital, Deferred Tax Asset Adjustments to Additional Paid in Capital, Deferred Tax Asset Fair Value, Recurring Fair Value, Recurring [Member] Concentration of Credit Risk Concentration Risk, Credit Risk, Policy [Policy Text Block] Liabilities, redeemable noncontrolling interest and stockholders' deficit/members' equity Liabilities and Equity [Abstract] Cover [Abstract] Cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Common unit, outstanding (in shares) Common Unit, Outstanding Maximum Maximum [Member] Useful life Finite-Lived Intangible Asset, Useful Life Net Intangible assets Finite-Lived Intangible Assets, Net Capitalized Internal Use Software Internal Use Software, Policy [Policy Text Block] Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Debt Instrument [Line Items] Debt Instrument [Line Items] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Training Center Agreement Training Center Agreement [Member] Training Center Agreement Andersen Aggregator LLC On Behalf of Directors Andersen Aggregator LLC On Behalf of Directors [Member] Andersen Aggregator LLC On Behalf of Directors Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] (Loss) income before income tax expense Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Schedule of Long-Term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Statement of Stockholders' Equity [Abstract] Schedule of Cash Flow, Supplemental Disclosures Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Right-of-use asset and lease liability adjustments due to remeasurement Right-Of-Use Asset and Lease Liability Adjustments Due to Remeasurement Right-Of-Use Asset and Lease Liability Adjustments Due to Remeasurement Due within one year or less Debt Securities, Held-to-Maturity, Unrealized Loss, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Year One Debt Securities, Held-to-Maturity, Unrealized Loss, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Year One Due within one year or less Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Year One Domestic Income (Loss) from Continuing Operations before Income Taxes, Domestic Schedule of Equity-based Compensation Expense Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Operating lease liabilities, current Operating leases Operating Lease, Liability, Current Capitalized internal use software Software and Software Development Costs [Member] Document Fiscal Period Focus Document Fiscal Period Focus Agreements Prior To Settlement In LTIP Units Agreements Prior To Settlement In LTIP Units [Member] Agreements Prior To Settlement In LTIP Units Award Timing Method Award Timing Method [Text Block] Litigation Case [Domain] Litigation Case [Domain] Furniture and fixtures Furniture and Fixtures [Member] Deferred revenue, noncurrent Contract with Customer, Liability, Noncurrent Award Type Award Type [Axis] Financing Receivable, after Allowance for Credit Loss, Current, Related Party [Extensible Enumeration] Financing Receivable, after Allowance for Credit Loss, Current, Related Party [Extensible Enumeration] Deferred compensation arrangement, vesting period Deferred Compensation Arrangement, Vesting Period Deferred Compensation Arrangement, Vesting Period Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Investment, Name [Domain] Investment, Name [Domain] Trading Symbol Trading Symbol 2029 Lessee, Operating Lease, Liability, to be Paid, Year Four Principal balance, threshold Debt Instrument, Principal Balance, Threshold Debt Instrument, Principal Balance, Threshold Change charged to equity Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Equity, Amount Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Equity, Amount Business Tax Services Business Tax Services [Member] Business Tax Services Valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent Membership interest units acquired (in shares) Membership Interest Units Acquired Membership Interest Units Acquired Members' Equity Member Units [Member] Entity Address, City or Town Entity Address, City or Town Weighted average discount rate—operating leases (in percent) Finance Lease, Weighted Average Discount Rate, Percent Intangible Assets, Net Intangible Assets Disclosure [Text Block] Total deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Statement of Income Location, Balance [Domain] Statement of Income Location, Balance [Domain] RSUs Restricted Stock Units (RSUs) [Member] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Entity Emerging Growth Company Entity Emerging Growth Company 2028 Long-Term Debt, Maturity, Year Three Schedule of Investments in Held to Maturity Debt Securities Debt Securities, Held-to-Maturity [Table Text Block] Accounts receivable Billed Contracts Receivable 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] Common stock, shares, outstanding (in shares) Common Stock, Shares, Outstanding Distributions paid Payments of Distributions to Affiliates Provision for credit losses on accounts receivable Accounts Receivable, Credit Loss Expense (Reversal) Unrealized losses Debt Securities, Held-to-Maturity, Unrealized Loss, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date [Abstract] Debt Securities, Held-to-Maturity, Unrealized Loss, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date Unrealized losses for these investments attributable to credit factors Total held-to-maturity securities Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss Accounts Receivable, Net Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Schedule of Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] TRA Parties TRA Parties [Member] TRA Parties Current taxes: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Deferred compensation expenses Deferred Compensation Arrangement with Individual, Compensation Expense Income tax payable Accrued Income Taxes, Current 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] Due between one and two years Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Between Year One And Two Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Between Year One And Two Number of service lines Number of Service Lines Number of Service Lines Nature of Operation, Product Information, Concentration of Risk [Table] Nature of Operation, Product Information, Concentration of Risk [Table] Schedule of Estimated Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Intangible Assets Intangible Assets, Finite-Lived, Policy [Policy Text Block] Prepaid expenses and other current assets Total prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Number of Units Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Income tax expense Income tax expense Income Tax Expense (Benefit) Common Class B Common Class B [Member] Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Short-term cash equivalent investments Cash, Cash Equivalents, and Short-Term Investments Due within one year or less Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Notes Payable Notes Payable, Other Payables [Member] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Operating Expenses Operating Expenses [Policy Text Block] Operating Expenses Less: accumulated depreciation and amortization Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, Accumulated Depreciation and Amortization All Trading Arrangements All Trading Arrangements [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] New Lease Terms New Lease Terms [Member] New Lease Terms Beginning balance (in shares) Ending balance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Commitments and Contingencies Disclosure [Abstract] Net cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Audit Information [Abstract] Audit Information Debt instrument, term Debt Instrument, Term Property, plant and equipment, useful life Property, Plant and Equipment, Useful Life Preferred stock par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Subsequent Event Subsequent Event [Member] Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] PEO Total Compensation Amount PEO Total Compensation Amount Depreciation and amortization expense Depreciation Long-Term Debt, Type [Axis] Long-Term Debt, Type [Axis] Numerator: Net Income (Loss) Available to Common Stockholders, Diluted [Abstract] Equity Components [Axis] Equity Components [Axis] Entity Ex Transition Period Entity Ex Transition Period Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Sublease income Sublease Income Standby Letters of Credit Standby Letters of Credit [Member] Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Operating expenses: Operating Costs and Expenses [Abstract] Valuation Services Valuation Services [Member] Valuation Services Number of reportable segments Number of Reportable Segments Deferred tax assets: Components of Deferred Tax Assets [Abstract] Entity Address, State or Province Entity Address, State or Province Principal payments under finance lease obligations Finance Lease, Principal Payments Antidilutive Security, Excluded EPS Calculation [Table] Antidilutive Security, Excluded EPS Calculation [Table] Total current liabilities Liabilities, Current Employee Compensation and Benefits Compensation Related Costs, General [Text Block] Individual: Individual [Axis] Triggering Event [Domain] Triggering Event [Domain] Triggering Event [Domain] Total matching contributions Defined Contribution Plan, Cost Total property and equipment Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, before Accumulated Depreciation and Amortization Income Tax Jurisdiction [Domain] Income Tax Jurisdiction [Domain] Property and equipment acquired through finance leases Right-of-Use Asset Obtained in Exchange for Finance Lease Liability Document Annual Report Document Annual Report Entities [Table] Entities [Table] Loss exposure, amount Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Entity Interactive Data Current Entity Interactive Data Current Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Member firm loans Member Firm Loans [Member] Member Firm Loans Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Long-Lived Tangible Asset [Axis] Long-Lived Tangible Asset [Axis] Ownership [Domain] Ownership [Domain] Gross amount of office equipment under finance leases, accumulated amortization Finance Lease, Right-of-Use Asset, Accumulated Amortization Goodwill Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block] Other assets Other Assets, Noncurrent Entity Central Index Key Entity Central Index Key PEO Name PEO Name Schedule of Future Maturities of Long-Term Debt Schedule of Maturities of Long-Term Debt [Table Text Block] 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] 2027 Purchase Obligation, to be Paid, Year Two Trademark and License Fees Trademark and License Fees [Member] Trademark and License Fees Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Beginning balance Ending balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Contingent consideration, net of current portion Business Combination, Contingent Consideration, Liability, Noncurrent Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Financial Instruments and Fair Value Measurements Financial Instruments Disclosure [Text Block] Deferred revenue Contract with Customer, Liability, Current Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Exercise Price Award Exercise Price Andersen Global Commitments Andersen Global Commitments [Member] Andersen Global Commitments Entity Filer Category Entity Filer Category Class of Stock Class of Stock [Domain] Unamortized compensation cost not yet recognized Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Federal statutory rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Subsequent Event Type [Axis] Subsequent Event Type [Axis] Contingent consideration Business Combination, Contingent Consideration, Liability, Current Nonrelated Party Nonrelated Party [Member] 2028 Finite-Lived Intangible Asset, Expected Amortization, Year Three Total loans and notes receivable from related parties Financing receivable, before allowance for credit loss Financing Receivable, before Allowance for Credit Loss Non-cash lease expense Non-cash Operating Lease, Expense Non-cash Operating Lease, Expense Gross Carrying Value Finite-Lived Intangible Assets, Gross 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] Number of states Number of States in which Entity Operates Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Accounts receivable, allowance for credit loss Accounts Receivable, Allowance for Credit Loss, Current Redeemable noncontrolling interest (Note 12) Balance Balance as of December 31, 2025 Redeemable Noncontrolling Interest, Equity, Carrying Amount Ownership [Axis] Ownership [Axis] Fair Value as of Grant Date Award Grant Date Fair Value Software In Development Software In Development [Member] Software In Development Operating loss carryforwards Operating Loss Carryforwards Deferred compensation liability Deferred Compensation Liability, Current and Noncurrent Due between one and two years Debt Securities, Held-to-Maturity, Unrealized Gain, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Between Year One And Two Debt Securities, Held-to-Maturity, Unrealized Gain, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Between Year One And Two Personnel costs Labor and Related Expense Deferred Bonus and Profit Sharing Arrangement, Individual Contract, Type of Deferred Compensation [Domain] Deferred Bonus and Profit Sharing Arrangement, Individual Contract, Type of Deferred Compensation [Domain] Floor interest rate (as percent) Debt Instrument, Floor Interest Rate Debt Instrument, Floor Interest Rate Share issued (in shares) Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Total operating expenses Costs and Expenses Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period Related Party Transaction [Line Items] Related Party Transaction [Line Items] Schedule of Outstanding Award, Activity, Excluding Option Share-Based Payment Arrangement, Outstanding Award, Activity, Excluding Option [Table Text Block] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Counterparty Name [Domain] Counterparty Name [Domain] Increase in operating right of use assets Increase (Decrease) In Operating Right of Use Assets Increase (Decrease) In Operating Right of Use Assets Number of offices Number Of Offices In Which Entity Operates Number Of Offices In Which Entity Operates 2027 Lessee, Operating Lease, Liability, to be Paid, Year Two Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Notes Payable, Noncurrent, Related Party [Extensible Enumeration] Notes Payable, Noncurrent, Related Party [Extensible Enumeration] Supplemental Balance Sheet Disclosures [Line Items] Supplemental Balance Sheet Disclosures [Line Items] Supplemental Balance Sheet Disclosures [Line Items] Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Non-PEO NEO Non-PEO NEO [Member] Outstanding amount Letters of Credit Outstanding, Amount Holdover Note Holdover Note [Member] Holdover Note Schedule of Prepaid Expenses and Other Current Assets Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block] Issuance of notes payable to related parties Notes Issued Sale of Stock [Axis] Sale of Stock [Axis] Allowance for credit loss Beginning balance Ending balance Financing Receivable, Allowance for Credit Loss All Award Types Award Type [Domain] 2026 Lessee, Operating Lease, Liability, to be Paid, Year One Equity Awards Adjustments Equity Awards Adjustments [Member] Leasehold improvements Leasehold Improvements [Member] Advertising costs Advertising Expense Other, net Other Noncash Income (Expense) Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Canada CANADA Compensation Amount Outstanding Recovery Compensation Amount Deferred taxes: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Alternative Investment Funds Alternative Investment Funds [Member] Alternative Investment Funds Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Equity restructuring costs Restructuring Charges [Member] Revenue recognized Contract with Customer, Liability, Revenue Recognized Underwriting discounts and commissions Sale of Stock, Underwriting Discounts And Commissions Sale of Stock, Underwriting Discounts And Commissions Accrued payroll and benefits Increase (Decrease) in Employee Related Liabilities Schedule of Changes in the Allowance for Credit Losses Accounts Receivable, Allowance for Credit Loss [Table Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Foreign income and withholding taxes Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent Denominator: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Documents Incorporated by Reference Documents Incorporated by Reference [Text Block] 2026 Long-Term Debt, Maturity, Year One Total deferred tax liabilities Deferred Tax Liabilities, Gross 2030 Long-Term Debt, Maturity, Year Five Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Minimum Minimum [Member] Reportable Segment Reportable Segment [Member] Reportable Segment Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Company Selected Measure Name Company Selected Measure Name Long-Term Debt Debt Disclosure [Text Block] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Operating cash flows used in operating leases Operating Lease, Payments Members' Equity Increase (Decrease) in Members' Equity [Roll Forward] Increase (Decrease) in Members' Equity Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Distributions payable Dividends Payable Net loss attributable to Andersen Group Inc. stockholders, diluted Net Income (Loss) Available to Common Stockholders, Diluted Amortization of capitalized implementation costs Capitalized Computer Software, Accumulated Amortization Foreign Current Foreign Tax Expense (Benefit) Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Weighted-average shares of Class A common stock outstanding, diluted (in shares) Weighted-average shares of Class A common stock outstanding, diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Segment Information Segment Reporting, Policy [Policy Text Block] Settlement of deferred compensation liability with LTIP Unit issuance and corresponding issuance of Class B common stock (in shares) Stock Issued During Period, Shares, Conversion of Units Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Entity Small Business Entity Small Business Payments of deferred offering costs Payments of Stock Issuance Costs Income Tax Disclosure [Abstract] Net income Net loss attributable to redeemable noncontrolling interest Net Income (Loss) Attributable to Redeemable Noncontrolling Interest 2029 Purchase Obligation, to be Paid, Year Four Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Commitment fee Line of Credit Facility, Commitment Fee Amount State Current State and Local Tax Expense (Benefit) Document Transition Report Document Transition Report Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Underlying Securities Award Underlying Securities Amount Equity Component [Domain] Equity Component [Domain] Document Period End Date Document Period End Date Accretion to redemption value of redeemable noncontrolling interest Temporary Equity, Accretion to Redemption Value Income Taxes Income Tax Disclosure [Text Block] Cash borrowings Proceeds from Lines of Credit Allowance for credit loss Balance at beginning of period Balance at end of period Accounts Receivable, Allowance for Credit Loss Common Class A Common Class A [Member] Deferred consideration payments for business combination Payment for Contingent Consideration Liability, Financing Activities Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Short-term lease costs Short-Term Lease, Cost Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Net income Net Income (Loss) Before Equity Restructuring Net Income (Loss) Before Equity Restructuring Operating lease liabilities Increase (decrease) in operating lease liability Increase (Decrease) in Operating Lease Liability Deferred Compensation Arrangement with Individual, Excluding Share-Based Payments and Postretirement Benefits [Line Items] Deferred Compensation Arrangement with Individual, Excluding Share-Based Payments and Postretirement Benefits [Line Items] Document Type Document Type Balance (in shares) Balance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding, Number Level 3 Fair Value, Inputs, Level 3 [Member] Loss Per Share Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Loss Contingencies [Table] Loss Contingencies [Table] Additional paid-in-capital Additional Paid in Capital Product and Service [Axis] Product and Service [Axis] Office equipment Office Equipment [Member] Variable lease costs Variable Lease, Cost Revenue Total revenue Revenue from Contract with Customer, Excluding Assessed Tax Total current assets Assets, Current Stewardship Funds Maturing on December 31, 2029 Stewardship Funds Maturing on December 31, 2029 [Member] Stewardship Funds Maturing on December 31, 2029 Statistical Measurement [Axis] Statistical Measurement [Axis] Due from related parties Other Receivables, Net, Current Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Net loss attributable to Andersen Group Inc. stockholders, basic Net Income (Loss) Available to Common Stockholders, Basic Entity Information [Line Items] Entity Information [Line Items] Current liabilities: Liabilities, Current [Abstract] Equity-based compensation Temporary Equity, Equity-Based Compensation Temporary Equity, Equity-Based Compensation Total operating expenses Operating Expenses Level 1 Fair Value, Inputs, Level 1 [Member] Beginning balance (in shares) Ending balance (in shares) Shares, Outstanding Proceeds from loans and notes receivable from related parties Repayment of Notes Receivable from Related Parties Related Party Transaction [Table] Related Party Transaction [Table] Net loss per share of Class A common stock, diluted (in dollars per share) Loss per share attributable to Class A common stockholders, diluted (in dollars per share) Earnings Per Share, Diluted Accounts receivable, net of allowance for credit losses of $1,676 and $3,071, respectively Accounts receivable, net Accounts Receivable, after Allowance for Credit Loss, Current Non-cash investing and financing transactions Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Compensation Related Costs [Abstract] Proceeds to purchase shares (in shares) Sale of Stock, Number of Shares Issued in Transaction Profits Interest Units (PIUs) Profits Interest Units (PIUs) [Member] Profits Interest Units (PIUs) Auditor Location Auditor Location Domestic Tax Jurisdiction Domestic Tax Jurisdiction [Member] Noncontrolling Interest [Abstract] Debt instrument, amortization period Debt Instrument, Amortization Period Debt Instrument, Amortization Period Less: amount representing interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Total operating lease costs Lease Cost, Operating Lease Cost, Operating Other non-deductible expenses Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Percent Income taxes paid Income Taxes Paid, Net 2027 Finite-Lived Intangible Asset, Expected Amortization, Year Two Class X Umbrella Units Class X Umbrella Units [Member] Class X Umbrella Units Collaborative Arrangement and Arrangement Other than Collaborative [Table] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Settlement of deferred compensation liability with LTIP Unit issuance Settlement Of Deferred Compensation Liability, LTIP Unit Issuance Settlement Of Deferred Compensation Liability, LTIP Unit Issuance Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Accrued payroll and benefits Employee-related Liabilities, Current Property and Equipment, Net Property, Plant and Equipment Disclosure [Text Block] Total lease payments Lessee, Operating Lease, Liability, to be Paid Property and equipment, net Total property and equipment, net Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization Interest income includes interest earned on loans and notes receivable from related parties Interest Income, Financing Receivable, before Allowance for Credit Loss Schedule of Other Current Liabilities Other Current Liabilities [Table Text Block] Trade Names Trade Names [Member] Expiration Date Trading Arrangement Expiration Date Other Commitments [Domain] Other Commitments [Domain] Noncontrolling interest Effective Income Tax Rate Reconciliation, Noncontrolling Interest Income (Loss), Percent Product Information [Line Items] Product Information [Line Items] Net loss per share: Net Income (Loss) Attributable to Parent [Abstract] Africa and Latin America Africa and Latin America [Member] Africa and Latin America Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Accounts receivable Increase (Decrease) in Accounts Receivable Entity Current Reporting Status Entity Current Reporting Status Receivables [Abstract] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Deferred Bonus and Profit Sharing Arrangements, Individual Contracts, Type of Deferred Compensation [Axis] Deferred Bonus and Profit Sharing Arrangements, Individual Contracts, Type of Deferred Compensation [Axis] Statement of Financial Position [Abstract] Executive Category: Executive Category [Axis] Non-personnel costs Other Operating Income (Expense), Net State and local taxes Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Loss contingency, accrual, current Loss Contingency, Accrual, Current Stewardship funds Stewardship Funds [Member] Stewardship Funds Finance lease liabilities Finance Lease, Liability, Current Current Fiscal Year End Date Current Fiscal Year End Date Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Schedule of Accounts Receivable, Net Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Redeemable Noncontrolling Interest Noncontrolling Interest Disclosure [Text Block] Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Antidilutive securities (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Purchase obligation Unrecorded Unconditional Purchase Obligation Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Accounts payable and other accrued expenses Accounts Payable and Accrued Liabilities, Current 2027 Long-Term Debt, Maturity, Year Two Leases Lessee, Operating Leases [Text Block] Net cash used in financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Measure: Measure [Axis] Write-offs, net of recoveries Accounts Receivable, Allowance for Credit Loss, Writeoff Net Of Recoveries Accounts Receivable, Allowance for Credit Loss, Writeoff Net Of Recoveries Reserves on loans and notes receivable from related parties Provision Financing Receivable, Credit Loss, Expense (Reversal) Private Client Services Private Client Services [Member] Private Client Services Summary of Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Long-Lived Tangible Asset [Domain] Long-Lived Tangible Asset [Domain] Cost of services (excluding depreciation and amortization) Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization Issuance of loans and notes receivable from related parties Origination of Notes Receivable from Related Parties Number of businesses acquired Business Combination, Number of Businesses Acquired Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Entity Tax Identification Number Entity Tax Identification Number Deferred consideration Business Combination, Separately Recognized Transactions, Deferred Consideration, Current Business Combination, Separately Recognized Transactions, Deferred Consideration, Current Common stock, shares, issued (in shares) Common Stock, Shares, Issued Weighted average remaining lease term in years—operating leases Operating Lease, Weighted Average Remaining Lease Term 2029 Long-Term Debt, Maturity, Year Four Schedule of Redeemable Noncontrolling Interest Redeemable Noncontrolling Interest [Table Text Block] Distributions payable to related parties Dividends Payable, Current Entity Public Float Entity Public Float Interest expense Interest Expense, Nonoperating Trading Arrangement: Trading Arrangement [Axis] Total Shareholder Return Amount Total Shareholder Return Amount Loss Contingencies [Line Items] Loss Contingencies [Line Items] Remeasurement (gain)/loss Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Contingent Consideration Contingent Consideration [Member] Contingent Consideration Security Exchange Name Security Exchange Name Capitalization of intangible assets Capitalized Computer Software, Net Purchases of property and equipment included in accounts payable and other accrued expenses Capital Expenditures Incurred but Not yet Paid Line of credit facility Line of Credit Facility, Maximum Borrowing Capacity Proceeds from IPO, net of underwriting discounts and commissions Proceeds from Issuance Initial Public Offering Operating expenses: Operating Expenses [Abstract] Prepaid expenses Prepaid Expense, Current Indefinite-Lived Intangible Assets, Major Class Name [Domain] Indefinite-Lived Intangible Assets, Major Class Name [Domain] Other current liabilities Total other current liabilities Other Liabilities, Current Liabilities Other Sundry Liabilities, Current Increase (Decrease) in Temporary Equity [Roll Forward] Increase (Decrease) in Temporary Equity [Roll Forward] Statement [Line Items] Statement [Line Items] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Cash and cash equivalents Cash and Cash Equivalent Subsequent Event [Line Items] Subsequent Event [Line Items] Common Stock Common Stock [Member] Vested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Payments are contingent upon the continued employment term Deferred Compensation Arrangement with Individual, Maximum Contractual Term Effect of dilutive Class X Umbrella Units (in shares) Weighted Average Number of Shares Outstanding, Diluted, Adjustment Notes payable to related parties, current portion Notes Payable, Current Statistical Measurement [Domain] Statistical Measurement [Domain] Thereafter Lessee, Operating Lease, Liability, to be Paid, after Year Five Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Related Party Transaction [Axis] Related Party Transaction [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Leases [Abstract] Schedule of Other Liabilities Other Noncurrent Liabilities [Table Text Block] Unbilled services Unbilled Contracts Receivable Implementation Costs for Cloud Computing Arrangements Implementation Costs For Cloud Computing Arrangements [Policy Text Block] Implementation Costs For Cloud Computing Arrangements Post-service obligation payment period Post-Service Obligation Payment Period Post-Service Obligation Payment Period Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Net loss per share of Class A common stock, basic (in dollars per share) Loss per share attributable to Class A common stockholders, basic (in dollars per share) Earnings Per Share, Basic Accounts payable and other accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Common stock reserved for issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Subtotal Deferred Tax Assets, Gross Schedule of Reportable Operating Segment Information Schedule of Segment Reporting Information, by Segment [Table Text Block] Total held-to-maturity securities Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain Cumulative Effect, Period of Adoption [Domain] Cumulative Effect, Period of Adoption [Domain] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Accounts and Financing Receivables [Table] Accounts and Financing Receivables [Table] Compensation expenses Total Share-Based Payment Arrangement, Expense Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Goodwill and Intangible Assets Disclosure [Abstract] Current assets: Assets, Current [Abstract] Total liabilities, redeemable noncontrolling interest and stockholders' deficit/ members' equity Liabilities and Equity Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] If Balance Is Less Than $550,000 If Balance Is Less Than $550,000 [Member] If Balance Is Less Than $550,000 2028 Purchase Obligation, to be Paid, Year Three Accounting Policies [Abstract] Revenue Recognition and Deferred Revenue [Abstract] Schedule of Operating Lease Maturity Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] AT Umbrella LLC LTIP Units AT Umbrella LLC LTIP Units [Member] AT Umbrella LLC LTIP Units East US East Region [Member] AT Umbrella LLC AT Umbrella LLC [Member] AT Umbrella LLC Pay vs Performance Disclosure [Line Items] Present value of lease liabilities Total lease liabilities Operating Lease, Liability Number of votes Common Stock, Number Of Votes Common Stock, Number Of Votes Schedule of Reconciliation of Valuation Allowance Summary of Valuation Allowance [Table Text Block] Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Class H Aggregator Units Class H Aggregator Units [Member] Class H Aggregator Units Other liabilities Total other liabilities Other Liabilities, Noncurrent Goodwill impairment Goodwill, Impairment Loss Statement of Cash Flows [Abstract] Company Selected Measure Amount Company Selected Measure Amount 2028 Lessee, Operating Lease, Liability, to be Paid, Year Three Other liabilities Increase (Decrease) in Other Noncurrent Liabilities Name Measure Name Schedule of Components of Income (Loss) Before Income Tax Expense Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Schedule of Changes in Contingent Consideration Measured at Fair Value on Recurring Basis Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Class of Stock [Line Items] Class of Stock [Line Items] Deferred tax liability Deferred Income Tax Liabilities, Net Issuance of threshold (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Issuance Of Threshold Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Issuance Of Threshold 2025 Equity Incentive Plan 2025 Equity Incentive Plan [Member] 2025 Equity Incentive Plan Total Long-Term Debt Legal Entity [Axis] Legal Entity [Axis] Total assets Assets 2026 Finite-Lived Intangible Asset, Expected Amortization, Year One Geographical [Domain] Geographical [Domain] Income Taxes Income Tax, Policy [Policy Text Block] Financing Receivable, Allowance for Credit Loss [Roll Forward] Financing Receivable, Allowance for Credit Loss [Roll Forward] Cash flows from operating activities: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Issuance of notes payable to related parties Notes Issued During Period, Value, Related Party Notes Issued During Period, Value, on Related Party Amortized Intangible Assets, Excluding Software In Development Amortized Intangible Assets, Excluding Software In Development [Member] Amortized Intangible Assets, Excluding Software In Development Notes payable to related parties, less current portion Notes Payable, Noncurrent Due between one and two years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, Between Year One And Two Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, Between Year One And Two Total held-to-maturity securities Debt Securities, Held-to-Maturity, Fair Value Variable Interest Entity Consolidation, Variable Interest Entity, Policy [Policy Text Block] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Change charged to income tax expense Valuation Allowance, Deferred Tax Asset, Effect on Income Tax Expense, Increase (Decrease) Valuation Allowance, Deferred Tax Asset, Effect on Income Tax Expense, Increase (Decrease) Right-of-use assets obtained in exchange for lease liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Adoption of ASC 326 Cumulative Effect, Period of Adoption, Adjustment [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Document Financial Statement Error Correction Document Financial Statement Error Correction [Flag] Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Operating Leases Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract] Related Party Related Party [Member] Schedule of Income Tax Expense (Benefit) Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Plan Name [Axis] Plan Name [Axis] Property and Equipment Property, Plant and Equipment, Policy [Policy Text Block] PEO PEO [Member] Office Leases To Extend Lease Term Office Leases To Extend Lease Term [Member] Office Leases To Extend Lease Term Lease Contractual Term [Domain] Lease Contractual Term [Domain] Interest income Investment Income, Interest Unpaid deferred offering costs included in accounts payable and other accrued expenses Unpaid Deferred Offering Costs Unpaid Deferred Offering Costs 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] 2030 Purchase Obligation, to be Paid, Year Five Undistributed Earnings and Accumulated Deficit Retained Earnings [Member] Income Tax Jurisdiction [Axis] Income Tax Jurisdiction [Axis] Share-Based Payment Arrangement [Abstract] Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement [Abstract] Thereafter Purchase Obligation, to be Paid, after Year Five Sale of Stock [Domain] Sale of Stock [Domain] Fair Value, Nonrecurring Fair Value, Nonrecurring [Member] If Balance Is At Least $550,000 If Balance Is At Least $550,000 [Member] If Balance Is At Least $550,000 Valuation Allowance [Roll Forward] Valuation Allowance [Roll Forward] Valuation Allowance Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Product and Service [Domain] Product and Service [Domain] Net (loss) income Net income Net (loss) income Net (loss) income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] City Area Code City Area Code Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Gain on reversal of legal accrual Gain (Loss) from Litigation Settlement Net deferred tax liability Deferred Tax Liabilities, Net Cash flows from investing activities: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Defined contribution plan, percent of match Defined Contribution Plan, Employer Matching Contribution, Percent of Match Related Party Transactions [Abstract] Total lease costs, net Lease, Cost Sales, general and administrative Selling, General and Administrative Expenses [Member] Cost of services Cost of Sales [Member] Goodwill Goodwill Schedule of Supplemental Cash Flow and Other Information Related to Leases Lease, Cost [Table Text Block] Lease Contractual Term [Axis] Lease Contractual Term [Axis] Reclassification of deferred offering costs paid in prior year to additional paid-in-capital upon IPO Reclassification of Deferred Offering Costs Paid in Prior Year to Additional Paid-In-Capital Upon IPO Reclassification of Deferred Offering Costs Paid in Prior Year to Additional Paid-In-Capital Upon IPO Federal Deferred Federal Income Tax Expense (Benefit) Auditor Name Auditor Name Organization and Business Description Nature of Operations [Text Block] Triggering Event [Axis] Triggering Event [Axis] Triggering Event Supplemental disclosures Supplemental Cash Flow Information [Abstract] Goodwill accumulated impairment Goodwill, Impaired, Accumulated Impairment Loss Other Performance Measure, Amount Other Performance Measure, Amount Central US Central Region [Member] US Central Region Investments in held-to-maturity debt securities, current Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss, Current Fixed Bonus Percentage Based on Revenues Generated Fixed Bonus Percentage Based on Revenues Generated [Member] Fixed Bonus Percentage Based on Revenues Generated Fair Value Measurement Fair Value Measurement, Policy [Policy Text Block] Related and Nonrelated Parties [Domain] Related and Nonrelated Parties [Domain] Distributions to members Dividends Dividends Over-Allotment Option Over-Allotment Option [Member] Net change in cash and cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Excluding Exchange Rate Effect, Including Discontinued Operation Deferred compensation final payment Deferred Compensation Arrangement with Individual, Distribution Paid Leases Lessee, Finance Leases [Text Block] Other current assets Other Assets, Current Entity [Domain] Entity [Domain] Net cash provided by (used in) investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Current portion of deferred revenue Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period 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] 2026 Purchase Obligation, to be Paid, Year One Interest paid Interest Paid, Excluding Capitalized Interest, Operating Activity Document Fiscal Year Focus Document Fiscal Year Focus Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Loans and notes receivable from related parties, net of allowance for credit losses of $2,513 and $1,480, respectively Financing Receivable, after Allowance for Credit Loss, Current Effective tax rate Effective Income Tax Rate Reconciliation, Percent Fixed lease costs Operating Lease, Cost Plan Name [Domain] Plan Name [Domain] Weighted-average period cost not yet recognized Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Fair value Debt Securities, Held-to-Maturity, Fair Value, Maturity [Abstract] Less valuation allowance Valuation allowance Balance at beginning of period Balance at end of period Deferred Tax Assets, Valuation Allowance Equity [Abstract] Deferred compensation term (in years) Deferred Compensation Arrangement with Individual, Requisite Service Period Amounts Payable to Related Parties Pursuant to Tax Receivable Agreement Payable to Related Parties Pursuant to Tax Receivable Agreement [Policy Text Block] Payable to Related Parties Pursuant to Tax Receivable Agreement Total Purchase Obligation West US West Region [Member] Segment Reporting Segment Reporting Disclosure [Text Block] Due within one year or less Debt Securities, Held-to-Maturity, Unrealized Gain, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Year One Debt Securities, Held-to-Maturity, Unrealized Gain, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Year One Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Loans and notes receivable from related parties, allowance for credit loss Financing Receivable, Allowance for Credit Loss, Current Federal Current Federal Tax Expense (Benefit) Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Schedule of Minimum Payments Other Commitments [Table Text Block] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Contingent consideration Business Combination, Contingent Consideration, Liability Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Amortization expense Amortization of Intangible Assets Leases Lessee, Leases [Policy Text Block] Sales, general and administrative Sales, general and administrative expenses Selling, General and Administrative Expense Depreciation and amortization Depreciation, Depletion and Amortization Loans and notes receivable from related parties, net of allowance for credit losses of $8,222 and $7,131, respectively Financing Receivable, after Allowance for Credit Loss, Noncurrent Revolving Credit Facility Revolving Credit Facility [Member] Accounts Receivable and Allowance for Credit Losses Accounts Receivable [Policy Text Block] Arrangement Duration Trading Arrangement Duration Other liabilities Other Sundry Liabilities, Noncurrent Computer equipment Computer Equipment [Member] Segments [Axis] Segments [Axis] Anderson Group Inc Anderson Group Inc [Member] Anderson Group Inc Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Local Phone Number Local Phone Number Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Thereafter Long-Term Debt, Maturity, after Year Five Equity-Based Compensation Share-Based Payment Arrangement [Text Block] Cancellation of Class B common stock (in shares) Stock Repurchased and Retired During Period, Shares Lessee, number of office leases Lessee, Operating Lease, Number Of Contracts Lessee, Operating Lease, Number Of Contracts Carrying amount Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure Assets Assets [Abstract] Credit Facility [Axis] Credit Facility [Axis] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Other Commitments [Axis] Other Commitments [Axis] Debt Instrument [Axis] Debt Instrument [Axis] Financial Instruments and Fair Value Measurements Fair Value Disclosures [Text Block] Credit Facility [Domain] Credit Facility [Domain] Stockholders' deficit/ members' equity: Equity, Attributable to Parent [Abstract] Vesting percentage Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage Interest rate Debt Instrument, Interest Rate, Stated Percentage Investment, Name [Axis] Investment, Name [Axis] Operating lease liabilities, noncurrent Operating leases Operating Lease, Liability, Noncurrent Entity Voluntary Filers Entity Voluntary Filers Deferred consideration, net of current portion Deferred Consideration Liability, Classified, Noncurrent Deferred Consideration Liability, Classified, Noncurrent Unrealized gains Debt Securities, Held-to-Maturity, Unrealized Gain, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date [Abstract] Debt Securities, Held-to-Maturity, Unrealized Gain, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date Held to maturity debt securities Interest Income, Debt Securities, Held-to-Maturity Total accounts receivable, net Accounts Receivable, after Allowance for Credit Loss Property, Plant and Equipment [Abstract] Entity Registrant Name Entity Registrant Name Other assets Increase (Decrease) in Other Noncurrent Assets Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Deferred compensation, net of current portion Deferred Compensation Liability, Classified, Noncurrent Investments in held-to-maturity debt securities Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss, Noncurrent Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Granted Other Receivable, after Allowance for Credit Loss, Current, Related Party [Extensible Enumeration] Other Receivable, after Allowance for Credit Loss, Current, Related Party [Extensible Enumeration] Number of operating segments Number of Operating Segments Partnership income not subject to tax Effective Income Tax Rate Reconciliation, Partnership Income Not Subject To Tax Effective Income Tax Rate Reconciliation, Partnership Income Not Subject To Tax Amortization of discount on held-to-maturity debt securities Accretion (Amortization) of Discounts and Premiums, Investments Granted, weighted average grant date fair value (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Related and Nonrelated Parties [Axis] Related and Nonrelated Parties [Axis] Cumulative Effect, Period of Adoption [Axis] Cumulative Effect, Period of Adoption [Axis] Member Notes Member Notes [Member] Member Notes Schedule of Intangible Assets, Net Schedule of Finite-Lived Intangible Assets [Table Text Block] Restatement Determination Date: Restatement Determination Date [Axis] Foreign Deferred Foreign Income Tax Expense (Benefit) Members' equity Balance Balance Members' Equity Interest expense Interest Expense, Debt Name Trading Arrangement, Individual Name Settlement of deferred compensation liability with LTIP Unit issuance and corresponding issuance of Class B common stock Conversion of units Stock Issued During Period, Value, Conversion of Units Payments for capitalized internal-use software costs Payments to Acquire Software Aggregate principal amount Debt Instrument, Face Amount Deferred Tax Asset, Valuation Allowance [Table] Deferred Tax Asset, Valuation Allowance [Table] Name Awards Close in Time to MNPI Disclosures, Individual Name Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Minimum future commitment Other Commitment Reclassification of members' equity to redeemable noncontrolling interest Reclassification of members' equity to redeemable noncontrolling interest Reclassification of Members' Equity to Noncontrolling Interests, Amount Reclassification of Members' Equity to Noncontrolling Interests, Amount ICFR Auditor Attestation Flag ICFR Auditor Attestation Flag Defined contribution plan, total compensation (as percent) Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Due between one and two years Debt Securities, Held-to-Maturity, Unrealized Loss, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Between Year One And Two Debt Securities, Held-to-Maturity, Unrealized Loss, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Between Year One And Two Equity-based compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Litigation Case [Axis] Litigation Case [Axis] Liability Class [Axis] Liability Class [Axis] Auditor Firm ID Auditor Firm ID Segments [Domain] Segments [Domain] U.S. federal and state net operating loss Deferred Tax Assets, Operating Loss Carryforwards, State and Local Statement of Income Location, Balance [Axis] Statement of Income Location, Balance [Axis] Foreign Income (Loss) from Continuing Operations before Income Taxes, Foreign Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Loss per Share Earnings Per Share, Policy [Policy Text Block] Principles of Consolidation and Redeemable Noncontrolling Interest Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block] Preferred stock, par value $0.0001 per share: 100,000,000 shares authorized, no shares issued and outstanding as of December 31, 2025 Preferred Stock, Value, Issued All Executive Categories All Executive Categories [Member] Schedule of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Common stock, value Common Stock, Value, Issued Commitments and contingencies (Note 17) Commitments and Contingencies Management Holdco Management Holdco [Member] Management Holdco Schedule of Nonvested Share Activity Schedule of Nonvested Share Activity [Table Text Block] Valuation Allowance [Line Items] Valuation Allowance [Line Items] Equity method investment, ownership percentage Equity Method Investment, Ownership Percentage Net deferred tax asset Deferred Tax Assets, Net Write-offs Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Other Balance Sheet Components Supplemental Balance Sheet Disclosures [Text Block] Scenario [Axis] Scenario [Axis] Stewardship Funds Maturing on December 31, 2033 Stewardship Funds Maturing on December 31, 2033 [Member] Stewardship Funds Maturing on December 31, 2033 Allowance for expected credit losses Debt Securities, Held-to-Maturity, Allowance for Credit Loss Proceeds from issuance of Class B common stock Proceeds from Issuance of Common Stock All Individuals All Individuals [Member] Long-Term Debt, Type [Domain] Long-Term Debt, Type [Domain] Fair Value Disclosures [Abstract] Loans and notes receivable from related parties, allowance for credit loss Financing Receivable, Allowance for Credit Loss, Noncurrent Payments for purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Point in time Transferred at Point in Time [Member] Name Forgone Recovery, Individual Name 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] Shares outstanding percentage Share-Based Compensation Arrangement by Share-Based Payment Award, Percentage of Outstanding Stock Maximum Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Intangible Asset, Finite-Lived [Table] Intangible Asset, Finite-Lived [Table] Class X Aggregator Units Class X Aggregator Units [Member] Class X Aggregator Units Geographical [Axis] Geographical [Axis] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Employee loans Employee Loan Program [Member] Employee Loan Program Forecast Forecast [Member] Depreciation and amortization Cost, Depreciation and Amortization Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Offering costs Offering Cost, Expense Title of 12(b) Security Title of 12(b) Security Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Reallocation of equity Reallocation of equity to controlling and noncontrolling interests Adjustments To Additional Paid In Capital, Reallocation Of Equity Adjustments To Additional Paid In Capital, Reallocation Of Equity Impairment of Long-Lived Assets Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block] Earnings Per Share [Abstract] 2030 Lessee, Operating Lease, Liability, to be Paid, Year Five Ownership percentage Subsidiary, Ownership Percentage, Parent Thereafter Finite-Lived Intangible Asset, Expected Amortization, After Year Three Finite-Lived Intangible Asset, Expected Amortization, After Year Three Schedule of Outstanding Share Totals With a Potentially Dilutive Impact Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Deferred revenue Increase (Decrease) in Contract with Customer, Liability Assets under construction Asset under Construction [Member] Accretion to redemption value of redeemable noncontrolling interest Redemption Premium Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Forfeitures Supplemental Balance Sheet Disclosures [Table] Supplemental Balance Sheet Disclosures [Table] Supplemental Balance Sheet Disclosures Award Timing Disclosures [Line Items] Measurement Frequency [Domain] Measurement Frequency [Domain] Vested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Exercised Stockholders’ Equity Equity [Text Block] State Deferred State and Local Income Tax Expense (Benefit) Maturity period Financing Receivable, Maturity Period Financing Receivable, Maturity Period Financing receivable, term Financing Receivable, Term Financing Receivable, Term Net loss attributable to Andersen Group Inc. Net loss Net Income (Loss) Attributable to Parent Subsequent Event [Table] Subsequent Event [Table] Schedule of Effective Income Tax Rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Annual anniversary of the vesting commencement Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Accounts Receivable, Allowance for Credit Loss [Roll Forward] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Annual shares authorized increase, percent of outstanding shares Share-Based Compensation Arrangement By Share-Based Payment Award, Authorized Shares Annual Increase, Board Of Directors Decision, Number Of Shares Share-Based Compensation Arrangement By Share-Based Payment Award, Authorized Shares Annual Increase, Board Of Directors Decision, Number Of Shares Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Preferred stock, authorized to issue (in shares) Preferred Stock, Shares Authorized Adoption Date Trading Arrangement Adoption Date Customer relationships Customer Relationships [Member] Operating (loss) income Total operating (loss) income Operating Income (Loss) Line of Credit Line of Credit [Member] Compensation Arrangements Compensation Related Costs, Policy [Policy Text Block] Accumulated deficit Retained Earnings (Accumulated Deficit) Defined contribution plan, maximum annual contributions per employer (as percent) Defined Contribution Plan, Maximum Annual Contributions Per Employer, Percent Defined Contribution Plan, Maximum Annual Contributions Per Employer, Percent Deferred Compensation Plan Non-Partner Employees, Director [Member] Non-Partner Employees, Director 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] Over time Transferred over Time [Member] State Tax Payments State Tax Payments [Member] State Tax Payments Purchases of held-to-maturity debt securities Payments to Acquire Held-to-Maturity Securities Class of Stock Class of Stock [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] 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] Other income, net Other Nonoperating Income (Expense) Statement [Table] Statement [Table] Deferred income tax Total deferred taxes Deferred Income Tax Expense (Benefit) Adjustments to reconcile net (loss) income to net cash provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Cash flows from financing activities: Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Deferred revenue Contract with Customer, Liability Finance lease liability, net of current portion Finance Lease, Liability, Noncurrent Partnership level items Deferred Tax Liabilities, Partnership Level Items Deferred Tax Liabilities, Partnership Level Items All Adjustments to Compensation All Adjustments to Compensation [Member] Amendment Flag Amendment Flag Sale of stock, price per share (in dollars per share) Sale of Stock, Price Per Share Computer software Computer software Software Development [Member] Termination Date Trading Arrangement Termination Date Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Andersen Tax Holdings LLC Andersen Tax Holdings LLC [Member] Andersen Tax Holdings LLC Weighted-average shares of Class A common stock outstanding, basic (in shares) Weighted average number of shares of Class A common stock outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Schedule of Basic and Diluted Net Loss Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Deferred compensation Deferred Compensation Liability, Current Related Party Transaction [Domain] Related Party Transaction [Domain] Subsequent Events [Abstract] Segment Reporting [Abstract] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Debt Disclosure [Abstract] Scenario [Domain] Scenario [Domain] Loyalty Retention Program Loyalty Retention Program [Member] Loyalty Retention Program Total accounts receivable Accounts Receivable, before Allowance for Credit Loss Credit Agreement Credit Agreement [Member] Credit Agreement Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Use of Estimates Use of Estimates, Policy [Policy Text Block] Payments of dividends Payments of Dividends Subsequent Events Subsequent Events [Text Block] Insider Trading Arrangements [Line Items] Number of Units Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward] Total liabilities Liabilities Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Commitment fee (as percent) Line of Credit Facility, Commitment Fee Percentage Intellectual property Intellectual Property [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Settlement of deferred compensation liability with LTIP Unit issuance Settlement of Deferred Compensation Liability With Long-Term Incentive Plan Unit Issuance Settlement of Deferred Compensation Liability With Long-Term Incentive Plan Unit Issuance Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Capital Account Notes Capital Account Notes [Member] Capital Account Notes Tradenames and trademarks Trademarks and Trade Names [Member] Equity restructuring costs Net loss from equity restructuring Net loss from equity restructuring Share-Based Payment Arrangement, Expense From Equity Restructuring Share-Based Payment Arrangement, Expense From Equity Restructuring Notes Payable, Current, Related Party [Extensible Enumeration] Notes Payable, Current, Related Party [Extensible Enumeration] Issuance of common stock Stock Issued During Period, Value, New Issues Counterparty Name [Axis] Counterparty Name [Axis] Schedule of Stock Unit Share-Based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] Deferred tax liabilities: Components of Deferred Tax Liabilities [Abstract] Deferred consideration liability Business Combination, Separately Recognized Transactions, Liabilities Recognized Proceeds from maturity of held-to-maturity debt securities Proceeds from Maturities, Prepayments and Calls of Held-to-Maturity Securities Total held-to-maturity securities Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Non-NEOs Non-NEOs [Member]