Additional Premium Real Estate Investment Banking Services, Additional Premium [Member] Real Estate Investment Banking Services, Additional Premium Definite life, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Servicing fees and other Servicing Fees And Other [Member] Servicing Fees And Other [Member] Maximum period of loans held for sale sold Maximum Period Of Loans Held For Sale Sold Maximum period of loans held for sale sold. Accounts payable, accrued expenses and other liabilities Business Combination, Recognized Liability Assumed, Liability, Current Award Timing Predetermined Award Timing Predetermined [Flag] Beginning Balance Ending Balance Valuation Allowance for Impairment of Recognized Servicing Assets, Balance Indefinite-lived Intangible Assets [Axis] Indefinite-Lived Intangible Assets [Axis] Class of warrant or right, issued upon conversion (in shares) Class Of Warrant Or Right, Issued Upon Conversion Class Of Warrant Or Right, Issued Upon Conversion Loans, forgivable loans and other receivables from employees and partners, net Increase (Decrease) in Due from Employee, Current Entity File Number Entity File Number Additional Paid-in Capital Additional Paid-in Capital [Member] Tabular List, Table Tabular List [Table Text Block] Recently Adopted Accounting Pronouncements and New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] SOFR Secured Overnight Financing Rate (SOFR) [Member] Investment sales Investment Advice [Member] Measurement Basis Measurement Basis [Axis] Adjustment to Compensation: Adjustment to Compensation [Axis] Related Party Transactions Related Party Transactions Disclosure [Text Block] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Restricted cash Restricted Cash, Current, At Fair Value Restricted Cash, Current, At Fair Value Other Other Assets, Miscellaneous, Current Revenues from Contracts with Customers Revenue from Contract with Customer [Text Block] Purchase Price Business Combination, Consideration Transferred [Abstract] Schedule of Stock by Class [Table] Stock, Class of Stock [Table] Schedule of Cash and Cash Equivalents Schedule of Cash and Cash Equivalents [Table Text Block] Other Other Assets, Miscellaneous, Noncurrent Adjustment to Compensation, Amount Adjustment to Compensation Amount Concentration risk percentage Concentration Risk, Percentage Other assets Increase (Decrease) in Other Operating Assets Consolidation Consolidation, Policy [Policy Text Block] CF Group Management, Inc. CF Group Management, Inc. [Member] CF Group Management, Inc. Schedule of Provisions for Risk Sharing Schedule Of Provision For Risk Sharing Obligations [Table Text Block] Schedule of provision for risk sharing obligations. Employee Stock Option Share-Based Payment Arrangement, Option [Member] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Taxes Income Taxes Paid Grantee Status [Domain] Grantee Status [Domain] Dividends to common stockholders Dividends, Common Stock, Cash Total stockholders’ equity Equity, Attributable to Parent Measurement Frequency Measurement Frequency [Axis] Insider Trading Policies and Procedures [Line Items] Schedule of Components of Fixed Assets, Net Property, Plant and Equipment [Table Text Block] Common stock, authorized (in shares) Common Stock, Shares Authorized Class of warrant or right, rights receiving exchangeability (in shares) Class Of Warrant Or Right, Rights Receiving Exchangeability Class Of Warrant Or Right, Rights Receiving Exchangeability Assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Issuance of Class A common stock for Newmark RSUs (in shares) Stock Issued During Period, Shares, New Issues Consolidated net income (loss), adjusted for non-cash and non-operating items Net Income Loss After Adjustments For Non-Cash And Nonoperating Items Net income loss after adjustments for noncash and nonoperating items. Fair Value, Recurring Fair Value, Recurring [Member] Liabilities Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value Warehouse facility due October 3, 2026 Warehouse Facility Due October Four Two Thousand Twenty Six [Member] Warehouse Facility Due October Four Two Thousand Twenty Six Award Period Two Award Period Two [Member] Award Period Two Liabilities, Redeemable Partnership Interests, and Equity: Liabilities and Equity [Abstract] Cover [Abstract] Cover [Abstract] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Maximum Maximum [Member] Newmark exchange shares (in shares) Incremental Common Shares Attributable To Exchange Incremental Common Shares Attributable To Exchange Property, Plant and Equipment, Net [Abstract] Property, Plant and Equipment, Net [Abstract] Less: Net income (loss) attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Non Distribution Earning Units Non Distribution Earning Units [Member] Non Distribution Earning Units [Member] Definite life, net carrying amount Finite-Lived Intangible Assets, Net Personal Asset Trust Howard W. Lutnick, Personal Asset Trust [Member] Howard W. Lutnick, Personal Asset Trust Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Unrealized gains (losses) outstanding Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss) Debt Instrument 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] Concentrations of Credit Risk Concentration Risk Disclosure [Text Block] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Estimated fair value of the post-termination payout Estimated fair value of limited partnership units Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Outstanding Grant Date Fair Value Share based compensation arrangement by share based payment award equity instruments other than options outstanding grant date fair value. Contributions of capital to and from Cantor for equity-based compensation Equity-Based Compensation, Contributions Of Capital To And From Cantor Equity-Based Compensation, Contributions Of Capital To And From Cantor Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Income (loss) before income taxes and noncontrolling interests Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Payable related to tax receivable agreement Payable related to Tax Receivable Agreement Tax Receivable Agreement, Liability, Noncurrent Tax Receivable Agreement, Liability, Noncurrent Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Schedule of Capital Markets Summary Of Capital Markets [Table Text Block] Summary of gains from mortgage banking activities, net. Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Schedule of Other Current Assets Schedule of Other Current Assets [Table Text Block] Earnings and tax distributions to limited partnership interests and other noncontrolling interests Payments to Noncontrolling Interests Texas TEXAS Right-of-use liabilities Operating Lease, Liability, Current Newmark Holdings, L.P. Newmark Holdings Limited Partnership [Member] Newmark holdings limited partnership. Software, including software development costs Software and Software Development Costs [Member] Document Fiscal Period Focus Document Fiscal Period Focus Receivables, net Receivable [Policy Text Block] Balance at beginning of period Balance at end of period Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Nonvested, Fair Value Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Nonvested, Fair Value Schedule of Quantitative Information about Level 3 Fair Value Measurements Fair Value Option, Disclosures [Table Text Block] Award Timing Method Award Timing Method [Text Block] Capital Markets Capital Markets Capital Markets [Member] Capital Markets Award Type Award Type [Axis] Newmark Holdings Units Parent Company Parent Company [Member] Mortgage Banking [Abstract] Mortgage Banking [Abstract] Trading Symbol Trading Symbol Fair value of non-vested Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested 2029 Lessee, Operating Lease, Liability, to be Paid, Year Four Interest expense Interest Expense, Long-Term Debt Schedule of Components of Other Intangible Assets Schedule of Intangible Assets and Goodwill [Table Text Block] Other (in shares) Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture Entity Address, City Entity Address, City or Town Probability of meeting earnout and contingencies Measurement Input Expected Earnout And Contingencies Rate [Member] Measurement input expected earnout and contingencies rate. Class of Financing Receivable [Axis] Class of Financing Receivable [Axis] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Proceeds from the sale of limited partnership interests Proceeds from Partnership Contribution Income Statement Location Statement of Income Location, Balance [Domain] Restricted Stock Units Restricted Stock Units (RSUs) [Member] Current Expected Credit Losses and Financial Guarantee Liability Credit Loss, Financial Instrument [Policy Text Block] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Total Business combination, consideration transferred Business Combination, Consideration Transferred Entity Emerging Growth Company Entity Emerging Growth Company Principal payments on warehouse facilities Repayments of Lines of Credit 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] Less: debt issue cost Debt Issuance Costs, Net Gain (loss) recognized in income for derivatives Derivative, Gain (Loss) on Derivative, Net Additions Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases Indefinite life, intangible assets Indefinite-Lived Intangible Assets (Excluding Goodwill) Common stock, outstanding (in shares) Shares outstanding at beginning of period (in shares) Shares outstanding at end of period (in shares) Common Stock, Shares, Outstanding Other Related Party Transactions With the CEO Other Related Party Transactions With the CEO [Member] Other Related Party Transactions With the CEO Provision (reversal) for doubtful accounts Accounts Receivable, Credit Loss Expense (Reversal) Mr. Gosin Chief Executive Officer [Member] Accrued compensation Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Accrued Compensation Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Accrued Compensation Reimbursement Premium Real Estate Investment Banking Services, Reimbursement Premium [Member] Real Estate Investment Banking Services, Reimbursement Premium Schedule of Revenues from Contracts with Customers and Our Other Sources of Revenues Disaggregation of Revenue [Table Text Block] Schedule of Changes in Common Stock Outstanding Schedule of Common Stock Outstanding Roll Forward [Table Text Block] Class of Financing Receivable [Domain] Class of Financing Receivable [Domain] Capital Markets Gains From Capital Markets [Member] Gains from mortgage banking activities/originations, net. Unit granted during period (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period 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] Schedule of Estimated Future Amortization Expense of Definite Life Intangible Assets Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Accrued compensation Increase (Decrease) in Accrued Salaries Provision (benefit) for income taxes Income Tax Expense (Benefit) Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Warehouse facility due September 25, 2026 Warehouse Facility Due September Twenty Five Two Thousand Twenty Six [Member] Warehouse Facility Due September Twenty Five Two Thousand Twenty Six Class B Common Stock Common Class B [Member] Opening Balance Closing Balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Document Information Document Information [Line Items] Fair Value Restricted Cash, Fair Value [Abstract] Restricted Cash, Fair Value Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Axis] Total, cost Property, Plant and Equipment, Gross Servicing fees Contractually Specified Servicing Fees, Amount Increase in discount rate Percentage Of Increase In Discount Rate Of Servicing Rights Percentage of increase in discount rate of servicing rights. RSUs (Treasury stock method) (in shares) Incremental Common Shares Attributable To Other Instruments Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of other instruments. Schedule of Guarantor Obligations [Table] Guarantor Obligation [Table] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Acquisitions Goodwill, Acquired During Period Distributions of income Temporary Equity, Distribution Of Income Temporary Equity, Distribution Of Income Compensation and employee benefits Cost, Direct Labor 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] Compliance with Regulatory Capital Requirements under Banking Regulations Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Outstanding limited partnership units - unvested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Exchange of Cantor Units for Newmark Class A common stock Stock Issued During Period, Value, Conversion Of Units, Fair Value Adjustments Stock Issued During Period, Value, Conversion Of Units, Fair Value Adjustments 6.125% Senior Notes Six Point One Two Five Percent Senior Notes [Member] Six point one two five percent senior notes. Operating lease, future contracted revenues and sublease income Operating Lease, Future Contracted Revenues And Sublease Income Operating Lease, Future Contracted Revenues And Sublease Income Net cash provided by (used in) operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Equity Method Investments and Joint Ventures [Abstract] Equity Method Investments and Joint Ventures [Abstract] Outstanding borrower advances, reimbursement period Outstanding Borrower Advances To Investors, Reimbursement Period Outstanding Borrower Advances To Investors, Reimbursement Period 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 Long-term Debt, Type Long-Term Debt, Type [Axis] Depreciation expense Depreciation 2026 Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year Allocations Business Combination, Recognized Asset Acquired, Asset [Abstract] Equity Components Equity Components [Axis] Property, Plant and Equipment Property, Plant and Equipment [Line Items] Sublease income Sublease Income Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Contingent consideration liability, measurement input Business Combination, Contingent Consideration, Liability, Measurement Input Number of reportable segments Number of Reportable Segments Share-based liabilities paid Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Share-Based Liabilities Paid Software development costs capitalized Capitalized Computer Software, Additions Mr. Joseph Alvarado Mr. Joseph Alvarado [Member] Mr. Joseph Alvarado Class of warrant or right, conversion ratio Class Of Warrant Or Right, Conversion Ratio Class Of Warrant Or Right, Conversion Ratio Entity Address, State Entity Address, State or Province Lease impairment Operating Lease, Impairment Loss Mortgage servicing rights, net Net Balance Servicing Asset Total current liabilities Liabilities, Current Limited Partnership Units Limited Partnership Units [Member] Limited partnership units. Individual: Individual [Axis] Employee loan amortization and other non-cash compensation expense Amortization Liabilities Liabilities, Total [Member] Beginning Balance Ending Balance Servicing Asset at Amortized Cost Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Entity Interactive Data Current Entity Interactive Data Current Conversion of common stock (in shares) Conversion Of Common Stock Conversion of common stock. Warehouse facilities collateralized by U.S. Government Sponsored Enterprises Outstanding draws Warehouse Agreement Borrowings Restricted cash and short-term investments Restricted cash and short-term investments Restricted Cash and Investments, Current Maximum loss potential Financial Guarantee Liability, Maximum Potential Loss Financial Guarantee Liability, Maximum Potential Loss Cantor Credit Agreement Cantor Credit Agreement [Member] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Property, Plant and Equipment, Type [Axis] Long-Lived Tangible Asset [Axis] Details for the Senior Notes Senior Notes [Abstract] Other assets (see Note 17) Total Other Assets, Noncurrent Entity Central Index Key Entity Central Index Key PEO Name PEO Name Total Revenues Revenues Total Revenues Redeemed/exchanged units (in shares) Share Based Compensation Arrangement By Share Based Payment Award Non Option Equity Instrument Redeemed Exchanged Number of exchangeable limited partnership units redeemed or exchanged into the Company's class A common stock during the period. 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] Fair Value, Balance Sheet Grouping, Financial Statement Captions Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Loan originations—loans held for sale Payment for Origination, Loan, Mortgage, Held-for-Sale Opening Balance Closing Balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Schedule of Basic Earnings Per Share Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table Text Block] Defined Benefit Plan [Table] Defined Benefit Plan [Table] Loans, Forgivable Loans and Other Receivables from Employees and Partners, net Loans, Forgivable Loans And Other Receivables From Employees And Partners, Net [Policy Text Block] Loans, Forgivable Loans And Other Receivables From Employees And Partners, Net Contingent consideration Business Combination, Contingent Consideration, Liability, Noncurrent Monthly payment on sublease Lessor, Operating Sublease, Lease Payment Lessor, Operating Sublease, Lease Payment Tranche One Share-Based Payment Arrangement, Tranche One [Member] Schedule of Fair Value of Derivative Contracts Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Exercise Price Award Exercise Price Entity Filer Category Entity Filer Category Class of Stock Class of Stock [Domain] Unrecognized compensation expense Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Subsequent Event Type Subsequent Event Type [Axis] Contingent consideration Business Combination, Contingent Consideration, Liability, Current Schedule of Changes in Level 3 RBC Forwards, Rate Lock Commitments, Forwards and Contingent Consideration Measured at Fair Value on Recurring Basis Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table Text Block] Fair value assets and liabilities measured on recurring basis unobservable input reconciliation. Long-term debt Long-Term Debt, Excluding Current Maturities Nonrelated Party Nonrelated Party [Member] Class of Warrant or Right [Domain] Class of Warrant or Right [Domain] 2029 Finite-Lived Intangible Asset, Expected Amortization, Year Three Vesting [Domain] Vesting [Domain] Mortgage Servicing Rights Mortgage Servicing Rights [Member] Mortgage servicing rights. 7.500% Senior Notes Seven Point Five Zero Zero Percent Senior Notes [Member] Seven Point Five Zero Zero Percent Senior Notes Definite life, gross amount 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] Additions Servicing Asset at Amortized Cost, Additions Entity Address, Street Entity Address, Address Line One Redeemable partnership interests Balance at beginning of period: Balance at end of period Temporary Equity, Including Noncontrolling Interest Allowance for doubtful accounts Accounts Receivable, Allowance for Credit Loss, Current Outstanding borrower advances Outstanding Borrower Advances To Investors Outstanding borrower advances to investors. Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract] Derivatives Derivative Instruments and Hedging Activities Disclosure [Text Block] Limited partnership units exchange ratio Limited Partnership Units Exchange Ratio Limited partnership units exchange ratio. Fair Value as of Grant Date Award Grant Date Fair Value Fair Value Amount Fair Value Amount [Roll Forward] Fair Value Amount [Roll Forward] Limited partnership units amortization RSU amortization Employee Benefits and Share-Based Compensation Schedule of Long-Term Debt Schedule of Long-Term Debt Instruments [Table Text Block] Total compensation and employee benefits Labor and related expense Labor and Related Expense Servicing Asset at Amortized Cost [Table] Servicing Asset at Amortized Cost [Table] Number of conversion rights 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 Related Party Transaction Related Party Transaction [Line Items] Document Quarterly Report Document Quarterly Report Schedule of Units Redeemed Share-Based Payment Arrangement, Outstanding Award, Activity, Excluding Option [Table Text Block] Long-term debt, fair value Long-Term Debt, Fair Value Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Counterparty Name [Domain] Counterparty Name [Domain] 2027 Lessee, Operating Lease, Liability, to be Paid, Year Two Financial Guarantee Liability Guarantees [Text Block] Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract] Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract] Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Warehouse line was temporarily increased Line of Credit Facility, Increase (Decrease), Net Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount General partners' capital account, units outstanding (in shares) General Partners' Capital Account, Units Outstanding Shares purchased for award (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Purchased for Award Cash Payments to Acquire Businesses, Gross Non-PEO NEO Non-PEO NEO [Member] Restricted cash and short-term investments Restricted Cash And Investments, Current, At Fair Value Restricted Cash And Investments, Current, At Fair Value Shares purchased for award (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Granted Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Granted Other Other Intangible Assets [Member] Decrease in fair value of servicing rights Servicing Asset at Fair Value, Period Increase (Decrease) Equity Award Award Type [Domain] 2026 Lessee, Operating Lease, Liability, to be Paid, Year One Noncontrolling interests Equity, Attributable to Noncontrolling Interest Equity Awards Adjustments Equity Awards Adjustments [Member] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Disaggregation of Revenue Disaggregation of Revenue [Line Items] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Compensation Amount Outstanding Recovery Compensation Amount Debt Instrument, Name Debt Instrument, Name [Domain] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Deferred revenue, revenue recognized Contract with Customer, Liability, Revenue Recognized Fair Value Estimate of Fair Value Measurement [Member] Committed Lines Committed Lines [Member] Committed lines. MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Other Current Assets and Other Assets Other Assets Disclosure [Text Block] Non-Exchangeable Mr. Merkel Holdings Non-Exchangeable Mr. Merkel Holdings [Member] Non-Exchangeable Mr. Merkel Holdings Contingent consideration, at cost Business Combination, Contingent Consideration, Liability, At Cost Business Combination, Contingent Consideration, Liability, At Cost Revenues: Revenues [Abstract] Rent and other deposits Deposit Assets Class of warrant or right, advance award (in shares) Class Of Warrant Or Right, Advance Award Class Of Warrant Or Right, Advance Award Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Joint Capital Raising and Advisory Services Authorization Joint Capital Raising and Advisory Services Authorization [Member] Joint Capital Raising and Advisory Services Authorization Schedule Of Acquired Finite And Indefinite Lived Intangible Asset By Major Class [Table] Schedule Of Acquired Finite And Indefinite Lived Intangible Asset By Major Class [Table] Schedule of acquired finite and indefinite lived intangible asset by major class. Financial Instruments Financial Instruments [Domain] Additions Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Award Date [Domain] Award Date [Domain] Warehouse Facilities Collateralized by U.S. Government Sponsored Enterprises Warehouse Lines Of Credit [Text Block] The entire disclosure for warehouse lines of credit. Percentage of contingent liability of actual losses incurred on outstanding loans Percentage Of Contingent Liability Of Actual Losses Incurred On Outstanding Loans Percentage of contingent liability of actual losses incurred on outstanding loans. Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Grant of exchangeability, redemption and issuance of Class A common stock Noncontrolling Interest Increase (Decrease) From Grant Of Exchangeability Redemption And Issuance Of Limited Partnership Interests Noncontrolling Interest Increase (Decrease) From Grant Of Exchangeability Redemption And Issuance Of Limited Partnership Interests Stock repurchased, gross (in shares) Stock Redeemed Or Called During Period, Shares, Gross Stock Redeemed Or Called During Period, Shares, Gross Finite-Lived Intangible Assets by Major Class Finite-Lived Intangible Assets by Major Class [Axis] Minimum Minimum [Member] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Banking Regulation, Regulatory Capital Requirement, Compliance [Table] Valuation Allowance Valuation Allowance for Impairment of Recognized Servicing Assets [Roll Forward] Measurement period and currency translation adjustments Goodwill, Measurement Period Adjustment Mr. Merkel Executive Vice President [Member] Accounts, Notes, Loans and Financing Receivable Accounts, Notes, Loans and Financing Receivable [Line Items] Company Selected Measure Name Company Selected Measure Name Fair Value Measurement Fair Value Measurement [Domain] Debt Debt Disclosure [Text Block] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Operating lease payments Operating Lease, Payments Forfeiture of Class A common stock Shares Issued, Value, Share-Based Payment Arrangement, Forfeited Allocated Revenue Real Estate Investment Banking Services, Allocated Revenue [Member] Real Estate Investment Banking Services, Allocated Revenue Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Net income (loss) for fully diluted shares Net income (loss) for fully diluted shares Net Income (Loss) Available to Common Stockholders, Diluted Goodwill Goodwill [Roll Forward] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Tranche Two Share-Based Payment Arrangement, Tranche Two [Member] Fully diluted weighted-average shares of common stock outstanding (in shares) Fully diluted weighted-average shares of common stock outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Segment Information Segment Reporting, Policy [Policy Text Block] Leasehold improvements, furniture and fixtures, and other fixed assets Lease Hold Improvements And Other Fixed Assets [Member] Leasehold improvements and other fixed assets. Exchange of Cantor Units for Newmark Class A common stock (in shares) Stock Issued During Period, Shares, Conversion of Units Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Restricted Stock Units Restricted Stock Award, Forfeitures [Abstract] Class of warrant or right percentage Class Of Warrant Or Right Percentage Class Of Warrant Or Right Percentage Entity Small Business Entity Small Business Outstanding limited partnership units (in shares) Limited Partners' Capital Account, Units Outstanding Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Document Transition Report Document Transition Report Net rentable area Net Rentable Area Debt discount amortization/Unused facility fee Debt Related Commitment Fees and Debt Issuance Costs Underlying Securities Award Underlying Securities Amount Repayment of debt Repayments of Other Long-Term Debt Uncommitted Lines Uncommitted Lines [Member] Uncommitted lines. Equity Component Equity Component [Domain] Document Period End Date Document Period End Date Number of employees Related Party Transaction, Number Of Sons Related Party Transaction, Number Of Sons Income Taxes Income Tax Disclosure [Text Block] Cash payment Class Of Warrant Or Right, Cash Waived Class Of Warrant Or Right, Cash Waived Allowance for credit loss Accounts Receivable, Allowance for Credit Loss Proceeds from warehouse facilities Proceeds from Lines of Credit Class A Common Stock Common Class A [Member] Total remaining draws on construction loans committed to fund Contractual Obligation Liquidation value of loans outstanding Liquidation Value Of Loans Outstanding Liquidation Value Of Loans Outstanding Number of tranches Class Of Warrant Or Right, Number Of Tranches Class Of Warrant Or Right, Number Of Tranches U.K. UNITED KINGDOM Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Short-term lease expense Short-Term Lease, Cost Higher borrowing capacity option Line Of Credit Facility, Accordion Feature, Higher Borrowing Capacity Option Line Of Credit Facility, Accordion Feature, Higher Borrowing Capacity Option Right-of-use liability Increase (Decrease) in Operating Lease Liability Total equity Balance at beginning of period Balance at end of period Equity, Including Portion Attributable to Noncontrolling Interest Shares repurchased price (in dollars per share) Average Price Paid per Share (in dollars per share) Shares Acquired, Average Cost Per Share Risks and Uncertainties [Abstract] Risks and Uncertainties [Abstract] Document Type Document Type Beginning balance (in shares) Ending 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] Earnings Per Share and Weighted-Average Shares Outstanding Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Loss Contingencies [Table] Loss Contingencies [Table] Product and Service Product and Service [Axis] Fannie Mae repurchase agreement, open maturity Fannie Mae Repurchase Agreement Open Maturity [Member] Fannie Mae repurchase agreement, open maturity. Revenues from contracts with customers: Mortgage Brokerage and Debt Placement Revenue from Contract with Customer, Excluding Assessed Tax Brokers and Dealers [Abstract] Broker-Dealer [Abstract] Total current assets Assets, Current Remaining from debt repurchase authorization Debt Instrument, Debt Repurchase Program Remaining Authorized Repurchase Amount Debt Instrument, Debt Repurchase Program Remaining Authorized Repurchase Amount Statistical Measurement [Axis] Statistical Measurement [Axis] Payout period for post-termination awards Post Termination Award Payout Period Post termination award payout period. Cash paid during the period for: Cash Paid During Period For [Abstract] Cash paid during period for. Equity-based compensation and allocation of net income to limited partnership units and FPUs Equity-based compensation and allocations of net income to limited partnership units and FPUs Equity Based Compensation And Allocation Of Net Income To Limited Partnership Units And FPUs Equity Based Compensation And Allocation Of Net Income To Limited Partnership Units And FPUs Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Capital and Liquidity Requirements Broker-Dealer Disclosure [Text Block] Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Net income (loss) available to common stockholders Net income (loss) available to common stockholders Net Income (Loss) Available to Common Stockholders, Basic Mortgage servicing right recognized Fees and Commissions, Mortgage Banking and Servicing Conversion percentage Class Of Warrant Or Right, Conversion Percentage Class Of Warrant Or Right, Conversion Percentage Current liabilities: Liabilities, Current [Abstract] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Schedule of Gain (Loss) on Change in Fair Value of Derivatives Included in Condensed Consolidated Statements of Operations Derivative Instruments, Gain (Loss) [Table Text Block] Operating expenses Operating Expenses Level 1 Fair Value, Inputs, Level 1 [Member] Long-term line of credit Long-Term Line of Credit Other Assets [Abstract] Other Assets [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Table] Fully diluted earnings per share (in dollars per share) Earnings Per Share, Diluted Receivables, net Accounts Receivable, after Allowance for Credit Loss, Current Supplemental disclosure of non-cash operating, investing and financing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Fair value, liability, recurring basis, unobservable input reconciliation, gain (loss), statement of income or comprehensive income flag Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Treasury stock, issued (in shares) Treasury Stock, Common, Shares Settled units (delivered shares) Share-Based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Settled, Fair Value Share-Based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Settled, Fair Value Securities Financing Transaction [Table] Security Financing Transaction [Table] Class of warrants or right, exchangeable (in shares) Class Of Warrants Or Right, Exchangeable Class Of Warrants Or Right, Exchangeable Investments Equity Method Investments and Joint Ventures Disclosure [Text Block] Percentage to preferred units per calendar year Percentage Of Profits Allocated To Preferred Partnership Units, Annual Percentage Rate Percentage Of Profits Allocated To Preferred Partnership Units, Annual Percentage Rate Accounts Payable, Accrued Expenses and Other Liabilities Accounts Payable and Accrued Liabilities Disclosure [Text Block] Other Stockholders' Equity, Other Foreclosure Loan Foreclosure [Member] Loan Foreclosure Michael J. Rispoli Chief Financial Officer [Member] Less: Interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Gains on originated mortgage servicing rights Gain On Originated Mortgage Servicing Rights Gain on originated mortgage servicing rights. 2028 Finite-Lived Intangible Asset, Expected Amortization, Year Two Trade and Loans Receivables Held-for-sale, Net, Not Part of Disposal Group [Abstract] Accounts and Financing Receivables, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance [Abstract] Principal balance Long-Term Debt, Gross Accrued compensation Employee-related Liabilities, Current Fixed Assets, Net Property, Plant and Equipment Disclosure [Text Block] Total lease payments Lessee, Operating Lease, Liability, to be Paid Delinquent Delinquent Loan [Member] Delinquent Loan Investment Sales Investment Sales [Member] Capital Markets Commissions [Member] Expiration Date Trading Arrangement Expiration Date Equity: Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Unrealized loss on marketable securities Equity Securities, FV-NI, Unrealized Gain (Loss) Fixed assets, net Total, net Property, Plant and Equipment, Net Dividends to stockholders Payments of Capital Distribution Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Receivables, net Increase (Decrease) in Accounts Receivable Construction Loans Construction Loans [Member] Entity Current Reporting Status Entity Current Reporting Status Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Revenue from External Customers by Products and Services [Table] Segment Reporting, Revenue from External Customer, Product and Service [Table] Notional Value Notional Value Of Limited Partnership Units With Post Termination Pay Out Amount Notional value of limited partnership units with post termination pay out amount. Schedule of Servicing Fees and Escrow Interest Schedule Of Servicing Fees And Escrow Interest [Table Text Block] Schedule of servicing fees and escrow interest. Consolidated Entities Consolidated Entities [Domain] Financial Instrument Financial Instrument [Axis] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Executive Category: Executive Category [Axis] Number of loans Number Of Loans Number Of Loans Borrowings of long-term debt Proceeds from Issuance of Long-Term Debt Howard W. Lutnick, Spouse and Trusts Howard W. Lutnick, Spouse And Trusts [Member] Howard W. Lutnick, Spouse And Trusts Total Interest Expense, Operating and Nonoperating Current Fiscal Year End Date Current Fiscal Year End Date Technology Technology-Based Intangible Assets [Member] Schedule of Limited Partnership Units with a Post-Termination Payout Schedule of Share-Based Compensation, Employee Stock Purchase Plan, Activity [Table Text Block] Service Agreements Service Agreements [Member] Finite-Lived Intangible Assets, Major Class Name Finite-Lived Intangible Assets, Major Class Name [Domain] Shares available for future awards (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Other tax receivables Other Tax Receivable, Noncurrent Other Tax Receivable, Noncurrent Fees to related parties Professional and consulting fees Professional Fees Assets Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value Derivative liability Derivative Liability Contractually specified servicing fee income, statement of income or comprehensive income flag Contractually Specified Servicing Fee Income, Statement of Income or Comprehensive Income [Extensible Enumeration] Mr. Lutnick Board of Directors Chairman [Member] Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Amount of capital in excess of aggregate regulatory requirements Banking Regulation, Total Risk-Based Capital, Excess, Actual Allocations of net income to limited partnership interests in Newmark Holdings, net of tax Allocation Of Income Loss To Limited Partnership Interest Diluted Allocation of income loss to limited partnership interest diluted. Limited Servicing Portfolio, Loans With Mortgage Servicing Rights Limited Servicing Portfolio, Loans With Mortgage Servicing Rights [Member] Limited Servicing Portfolio, Loans With Mortgage Servicing Rights Schedule of Fair Value Hierarchy of Financial Assets and Liabilities under U.S. GAAP Guidance Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Spouse Howard W. Lutnick, Spouse [Member] Howard W. Lutnick, Spouse Acquisitions from 2022 through 2025 Acquisitions From Two Thousand Twenty Two Through Two Thousand Twenty Five [Member] Acquisitions from 2022 through 2025. Anti-dilutive securities excluded from computation of fully diluted earnings per share amount (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Weighted-average shares: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Liabilities, Unobservable Input Reconciliation: Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Leases Lessee, Operating Leases [Text Block] Net cash provided by (used in) financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Measure: Measure [Axis] Award Period Three Award Period Three [Member] Award Period Three Other Income (loss), Net Other Income (Loss) Net [Policy Text Block] Other Income (Loss) Net Discount Rate One Discount Rate One [Member] Discount rate one. Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Provision (reversal) for expected credit losses Provision for expected credit losses Provision (Reversal) For Risk Sharing Obligations Provision for risk-sharing obligations. Property, Plant and Equipment, Type [Domain] Long-Lived Tangible Asset [Domain] Remaining from debt repurchase authorization Approximate Dollar Value of Units and Shares That May Yet Be Repurchased/ Purchased Under the  Program Share Repurchase Program, Remaining Authorized, Amount Schedule of Current Portion of Accounts Payable, Accrued Expenses and Other Liabilities Schedule Of Accounts Payable Accrued Liabilities And Other Liabilities Current [Table Text Block] Schedule of accounts payable, accrued liabilities and other liabilities, current. Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Authorized amount Debt Instrument, Debt Repurchase Program Authorized Amount Debt Instrument, Debt Repurchase Program Authorized Amount Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Debt issue cost amortization Amortization of Debt Issuance Costs Entity Tax Identification Number Entity Tax Identification Number Grantee Status [Axis] Grantee Status [Axis] Issuance of common stock and exchangeability expenses Issuance of common stock and exchangeability expenses Common Stock, Exchangeability Granted, Issued, Expense Common Stock, Exchangeability Granted, Issued, Expense Common stock, conversion for each restricted stock unit settled (in shares) Common Stock, Conversion For Each Restricted Stock Unit Settled Common Stock, Conversion For Each Restricted Stock Unit Settled Limit on loans that have not yet been acquired or sold Related Party Transaction Limit On Loan Not Yet Acquired Or Sold Related Party Transaction Limit On Loan Not Yet Acquired Or Sold Present value of expected payments Valuation Technique, Discounted Cash Flow [Member] Allowance for doubtful accounts, period increase (decrease) Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease) Mortgage Servicing Rights Mortgage Servicing Rights [Line Items] Mortgage servicing rights. Delinquency threshold period Financial Guarantee Liability, Delinquency Threshold Period Financial Guarantee Liability, Delinquency Threshold Period Mortgage Servicing Rights, Net Mortgage Servicing Rights [Text Block] The entire disclosure for mortgage servicing rights. Seller/Servicer Agreements Seller Servicer Agreements [Member] Seller servicer agreements. Common stock, issued (in shares) Common Stock, Shares, Issued Conversion percentage, tranche four Class Of Warrant Or Right, Tranche Four Class Of Warrant Or Right, Tranche Four Weighted average lease term Operating Lease, Weighted Average Remaining Lease Term Schedule of Changes in Carrying Amount of Redeemable Partnership Interest Redeemable Noncontrolling Interest [Table Text Block] Common stock, votes per share Number Of Votes Per Common Share Number Of Votes Per Common Share Goodwill and Other Intangible Assets, Net Goodwill and Intangible Assets Disclosure [Text Block] Thereafter Finite-Lived Intangible Asset, Expected Amortization, after Year Four Finite-Lived Intangible Asset, Expected Amortization, after Year Four Schedule of Changes in Carrying Amount of Goodwill Schedule of Goodwill [Table Text Block] Trading Arrangement: Trading Arrangement [Axis] Derivative assets Derivative Asset, Current Total Shareholder Return Amount Total Shareholder Return Amount Loss Contingencies Loss Contingencies [Line Items] Total realized and unrealized gains (losses) included in Net income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Security Exchange Name Security Exchange Name Schedule of Acquired Finite And Indefinite Lived Intangible Asset By Major Class Schedule Of Acquired Finite And Indefinite Lived Intangible Asset By Major Class [Line Items] Schedule of acquired finite and indefinite lived intangible asset by major class. Loans Held for Sale, at Fair Value Financing Receivables [Text Block] Limited Partnership Interests in Newmark Holdings and BGC Holdings Partners' Capital Notes Disclosure [Text Block] Maximum revolving credit Line of Credit Facility, Maximum Borrowing Capacity Aggregated repurchased (in shares) Stock Repurchased During Period, Shares Prepaid expenses Prepaid Expense, Current Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-Lived Intangible Assets, Major Class Name [Domain] Annual cash bonus Related Party Transaction, Annual Cash Bonus Related Party Transaction, Annual Cash Bonus Asset Class Asset Class [Domain] Interest rate in the period Line of Credit Facility, Interest Rate During Period Total realized and unrealized gains (losses) included in Net income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Increase (Decrease) in Temporary Equity Increase (Decrease) in Temporary Equity [Roll Forward] Accounts payable and accrued expenses Accounts Payable And Accrued Expenses Current Accounts payable and accrued expenses, current. Conversion percentage, tranche two Class Of Warrant Or Right, Tranche Two Class Of Warrant Or Right, Tranche Two Statement Statement [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Cash and cash equivalents Cash and Cash Equivalent Subsequent Event Subsequent Event [Line Items] Additional share authorized (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized Loan originations related fees and sales premiums, net Loan Originations Related Fees and Sales Premiums, Net Loan Originations Related Fees And Sales Premiums Net [Member] Loan Originations Related Fees And Sales Premiums Net Common Stock Common Stock [Member] Net increase (decrease) in cash and cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Ancillary fee income, servicing financial asset, statement of income or comprehensive income flag Ancillary Fee Income, Servicing Financial Asset, Statement of Income or Comprehensive Income [Extensible Enumeration] Dividends declared and paid per share of common stock (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Guarantor Obligations Guarantor Obligations [Line Items] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Chief Operating Officer Chief Operating Officer [Member] Statistical Measurement [Domain] Statistical Measurement [Domain] Fixed assets, net Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment Thereafter Lessee, Operating Lease, Liability, to be Paid, after Year Five Operating lease, liability, current, statement of financial position flag Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Restricted cash Restricted Cash, Current Related Party Transaction 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] Gross amount Intangible Assets, Gross (Excluding Goodwill) Asset Class Asset Class [Axis] Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Leases [Abstract] Leases [Abstract] Basic earnings per share Earnings Per Share, Basic [Abstract] Schedule of Other Long-term Liabilities Other Noncurrent Liabilities [Table Text Block] BGC Holdings Units B G C Holdings Limited Partnership [Member] BGC Holdings Limited Partnership. Interest expense, net Interest expense, net Interest Income (Expense), Nonoperating Loans, forgivable loans and other receivables from employees and partners, net Other Receivable, after Allowance for Credit Loss, Noncurrent Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Warrants and rights outstanding (in shares) Class of Warrant or Right, Outstanding Federal Funds Rate Fed Funds Effective Rate Overnight Index Swap Rate [Member] Basic earnings per share (in dollars per share) Earnings Per Share, Basic Gains (losses) recognized on change in fair value on loans held for sale Gains Losses Recognized For Change In Fair Value On Loans Held For Sale Gains (losses) recognized on change in fair value on loans held for sale. Schedule of Company Lines Available and Borrowings Outstanding Schedule of Line of Credit Facilities [Table Text Block] Percentage to preferred units Percentage Of Profits Allocated To Preferred Partnership Units Percentage of profits allocated to preferred partnership units. Schedule of Restricted Cash and Short-Term Investments Restrictions On Cash, Cash Equivalent And Investment [Table Text Block] Restrictions On Cash, Cash Equivalent And Investment Award Date [Axis] Award Date [Axis] Discount rate Measurement Input, Discount Rate [Member] Schedule of Revenue by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Interest income on loans held for sale Interest and Fee Income, Loan, Mortgage, Held-for-Sale Compensation and employee benefits Cost Of Services Direct Labor [Member] Cost of services direct labor. Revenue, remaining performance obligation, amount Revenue, Remaining Performance Obligation, Amount Measurement Input Type Measurement Input Type [Domain] Unrealized gains (losses) outstanding Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Restricted short-term investments (greater than three months maturity) Restricted Short-Term Investments, Current, At Fair Value Restricted Short-Term Investments, Current, At Fair Value Capital Units by Class Capital Units by Class [Axis] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Accounts and Financing Receivables [Table] Related party transaction, one time cash payment Related Party Transaction, One Time Cash Payment Related Party Transaction, One Time Cash Payment Derivative Instruments, Gain (Loss) Derivative Instruments, Gain (Loss) [Line Items] Compensation expense (benefit) Total compensation expense Share-Based Payment Arrangement, Expense Hedging Designation Hedging Designation [Domain] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Current assets: Assets, Current [Abstract] Total liabilities, redeemable partnership interests, and equity Liabilities and Equity Concentration Risk Benchmark Concentration Risk Benchmark [Axis] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Schedule of Changes in the Carrying Amount of Mortgage Servicing Rights Servicing Asset at Amortized Cost [Table Text Block] Income allocation Temporary Equity, Net Income License agreements (GSE) Licensing Agreements [Member] Unrealized (gains) on loans held for sale Unrealized (Gains) Loss On Loans Held For Sale Unrealized gains loss on loans held for sale. Guarantees [Abstract] Guarantees [Abstract] Accounting Policies [Abstract] Accounting Policies [Abstract] Advances on long-term contracts Advances On Contracts, Noncurrent Advances On Contracts, Noncurrent Schedule of Minimum Lease Payments Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] Concentration Risk Type Concentration Risk Type [Domain] Forward Sales Contracts Forward Contracts [Member] Treasury Stock Treasury Stock, Common [Member] Pay vs Performance Disclosure [Line Items] Share issuances: Share Issuance [Abstract] Share issuance. Class of Warrant or Right [Axis] Class of Warrant or Right [Axis] Operating lease, liability Present value of lease liability Operating Lease, Liability Management Services Management Services [Member] Management services. Outstanding loan balances Financial Guarantee Liability, Credit Risk Service Loans Financial Guarantee Liability, Credit Risk Service Loans Acquisitions Business Combination [Text Block] Depreciation and amortization Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Stock repurchased (in shares) Stock Redeemed or Called During Period, Shares Other long-term liabilities (see Note 26) Total Other Liabilities, Noncurrent Assets, Unobservable Input Reconciliation: Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Exchangeable Limited Partnership Interests Exchangeable Limited Partnership Interests [Member] Exchangeable Limited Partnership Interests Goodwill impairment loss Goodwill, Impairment Loss Newmark Equity Plan Long Term Equity Incentive Plan [Member] Long term equity incentive plan. Accounts payable, accrued expenses and other liabilities Increase (Decrease) in Other Accounts Payable and Accrued Liabilities Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Company Selected Measure Amount Company Selected Measure Amount 2028 Lessee, Operating Lease, Liability, to be Paid, Year Three Debt issuance costs, gross Debt Issuance Costs, Gross Fair value, asset, recurring basis, unobservable input reconciliation, gain (loss), statement of income or comprehensive income flag Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Comprehensive income (loss) available to common stockholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Measurement Input Type Measurement Input Type [Axis] Guaranty Liability: Guaranty Liabilities [Roll Forward] Guaranty Liabilities [Roll Forward] Name Measure Name Non-Exchangeable Newmark Holdings PSUs Non-Exchangeable Newmark Holdings PSUs [Member] Non-Exchangeable Newmark Holdings PSUs Employee Loans, Compensation Expense Employee Loans, Compensation Expense [Member] Employee Loans, Compensation Expense Class of Stock Class of Stock [Line Items] Payroll and other taxes payable Accrued Payroll And Other Taxes Payable, Noncurrent Accrued Payroll And Other Taxes Payable, Noncurrent Mortgage Servicing Rights [Table] Mortgage Servicing Rights [Table] Mortgage servicing rights. Escrow and Custodial Funds Escrow And Custodial Funds [Text Block] Escrow and custodial funds. Payables to related parties Increase (Decrease) in Accounts Payable, Related Parties Total Long-term debt Long-Term Debt Legal Entity Legal Entity [Axis] Total assets Total assets Assets 2027 Finite-Lived Intangible Asset, Expected Amortization, Year One Settled units (delivered shares) (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Geographical Geographical [Domain] Advisory fee, percentage Related Party Transaction, Advisory Fee, Gross Proceeds, Percentage Related Party Transaction, Advisory Fee, Gross Proceeds, Percentage CASH FLOWS FROM OPERATING ACTIVITIES: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Debt instrument, adjustment rate Debt Instrument, Adjustment Rate Debt Instrument, Adjustment Rate Weighted- Average Remaining Life (Years) Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life Concentration Risk Type Concentration Risk Type [Axis] Capital Markets Capital Markets [Text Block] Capital Markets Founding partner interest General Partner [Member] Related party transaction, annual compensation, cash-based and share-based awards Related Party Transaction, Annual Compensation, Cash-Based And Share-Based Awards Related Party Transaction, Annual Compensation, Cash-Based And Share-Based Awards 2030 Finite-Lived Intangible Asset, Expected Amortization, Year Four Impairment charges Impairment, Long-Lived Asset, Held-for-Use Dividends declared per share of common stock (in dollars per share) Common Stock, Dividends, Per Share, Declared Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Total Contractually Specified Servicing Fees Ancillary Fees Escrow Interest And Placement Fees Earned In Exchange For Servicing Financial Assets Contractually specified servicing fees, ancillary fees, escrow interest and placement fees earned in exchange for servicing financial assets. Right-of-use assets and liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Grant of exchangeability, redemption and issuance of Class A common stock (in shares) Grant Of Exchangeability Redemption And Issuance Of Limited Partnership Interests And Issuance Of Common Stock Shares Grant of exchangeability, redemption and issuance of limited partnership interests and issuance of common stock, shares. Level 2 Fair Value, Inputs, Level 2 [Member] Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Business Combination Business Combination [Domain] Lessee, Operating Lease, Liability, Payment, Due Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract] Related Party Related Party [Member] Medical benefits period Restructuring And Related Cost, Severance Costs, Medical Benefits, Period Restructuring And Related Cost, Severance Costs, Medical Benefits, Period Plan Name Plan Name [Axis] Document Information [Table] Document Information [Table] PEO PEO [Member] Ancillary fees Ancillary Fee Income Generated by Servicing Financial Assets, Amount U.S. UNITED STATES 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] Limit on loans outstanding Related Party Transaction Limit On Loan Outstanding Related Party Transaction Limit On Loan Outstanding Sale of Class A Common Stock to Company Sale of Class A Common Stock to Company [Member] Sale of Class A Common Stock to Company Retained Earnings Retained Earnings [Member] Mr. Lutnick Howard W. Lutnick [Member] Howard W. Lutnick Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] Cash and cash equivalents and restricted cash at beginning of period Cash and cash equivalents and restricted cash at end of period Cash and cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement [Abstract] Income Statement [Abstract] Derivative asset Derivative Asset Corporate taxes payable Taxes Payable, Current Fair Value, Measurements, Nonrecurring Fair Value, Nonrecurring [Member] Issuance and other Temporary Equity, Stock Issued During Period, Value, New Issues Marketable securities Investments, Fair Value Disclosure Other intangible assets, net Net carrying amount Intangible Assets, Net (Excluding Goodwill) Provision (benefit) for credit losses on the financial guarantee liability Off-Balance-Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal) Other Other Geographical Areas [Member] Other Geographical Areas Product and Service [Domain] Product and Service [Domain] Consolidated net income (loss) Consolidated net income (loss) Consolidated net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Total Liabilities, Fair Value Disclosure Business Combination [Table] Business Combination [Table] Notional Amounts Derivative, Notional Amount Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Tax receivable agreement, cash savings, percentage Tax Receivable Agreement, Cash Savings, Percentage Tax Receivable Agreement, Cash Savings, Percentage Schedule of Components of Purchase Consideration Transferred and Preliminary Allocation of Assets Acquired and Liabilities Assumed Business Combination, Recognized Asset Acquired and Liability Assumed [Table Text Block] Contingent consideration Contingent Consideration Liability [Member] Contingent Consideration Liability [Member] Equity-based compensation and allocations of net income to limited partnership units and FPUs Equity-Based Compensation And Allocations Of Net Income To Limited Partnership Units And FPUs Equity-Based Compensation And Allocations Of Net Income To Limited Partnership Units And FPUs Schedule of Fully Diluted Earnings Per Share Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table Text Block] City Area Code City Area Code Shares withheld for tax withholding obligation (in shares) Stock Redeemed Or Called During Period, Shares Withheld For Tax Withholding Obligation, Shares Stock Redeemed Or Called During Period, Shares Withheld For Tax Withholding Obligation, Shares Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Proceeds from long-term lines of credit Proceeds from Long-Term Lines of Credit Lines available Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases CASH FLOWS FROM INVESTING ACTIVITIES: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Operating, administrative and other General and Administrative Expense Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Related Party Transactions [Abstract] Related Party Transactions [Abstract] Rent expense Lease, Cost Goodwill Beginning balance Ending balance Goodwill Interest Expense and Amortization of Debt Issue Costs Interest Expense, Debt [Abstract] Concentration Risk [Table] Concentration Risk [Table] Minimum gross revenue threshold Class Of Warrant Or Right, Threshold, Minimum Gross Revenue Class Of Warrant Or Right, Threshold, Minimum Gross Revenue Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] Receivables, net Business Combination, Recognized Asset Acquired, Receivable, Current Revenue from External Customer Revenue from External Customer [Line Items] Other Performance Measure, Amount Other Performance Measure, Amount Weighted- Average Grant Date Fair Value Per Share Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Schedule of Restricted Cash Restrictions on Cash and Cash Equivalents [Table Text Block] Related party transaction, referral fee, amounts received Related Party Transaction, Referral Fee, Amounts Received Related Party Transaction, Referral Fee, Amounts Received Maximum amount per loan Related Party Transaction Maximum Amount Per Loan Related Party Transaction Maximum Amount Per Loan Related Party, Type [Domain] Related and Nonrelated Parties [Domain] Dividends declared per share of common stock, increase (in dollars per share) Common Stock, Dividends, Per Share, Declared, Increase (Decrease) Common Stock, Dividends, Per Share, Declared, Increase (Decrease) Credit Concentration Risk Credit Concentration Risk [Member] Operating lease, liability, including sublease receivables Operating Lease, Liability, Including Sublease Receivables Operating Lease, Liability, Including Sublease Receivables Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] Forfeited of shares (in shares) Shares Issued, Shares, Share-Based Payment Arrangement, Forfeited Derivative Instrument Derivative Instrument [Axis] Vesting [Axis] Vesting [Axis] Liabilities: Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Other current assets (see Note 17) Total Other Assets, Current Additional paid-in capital Additional Paid in Capital, Common Stock Entity [Domain] Entity [Domain] Net cash provided by (used in) investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Revenue, remaining performance obligation, expected timing of satisfaction, period 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] Interest 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] Right-of-use assets Operating Lease, Right-of-Use Asset Provision (reversal) for expected credit losses Provision (Reversal) For Risk Sharing Obligations And Settlement Provision (Reversal) For Risk Sharing Obligations And Settlement Operating lease costs Operating Lease, Cost Plan Name Plan Name [Domain] Cost Basis Reported Value Measurement [Member] Cost not yet recognized, period for recognition Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Receivable from related parties Increase (Decrease) in Accounts Receivable, Related Parties Unit exercised during period (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period Mortgage brokerage and debt placement Mortgage Brokerage and Debt Placement Mortgage Brokerage And Debt Placement [Member] Mortgage Brokerage And Debt Placement Equity [Abstract] Equity [Abstract] Financing receivable, nonaccrual Financing Receivable, Nonaccrual Goodwill and Other Intangible Assets, net Goodwill and Intangible Assets, Policy [Policy Text Block] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Not Designated as Hedging Instrument Not Designated as Hedging Instrument [Member] New Accounting Pronouncements or Change in Accounting Principle New Accounting Pronouncements or Change in Accounting Principle [Line Items] Increase (Decrease) in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Newmark Holdings NPSUs Newmark Holdings NPSUs [Member] Newmark Holdings NPSUs Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Contingent consideration Contingent consideration Business Combination, Contingent Consideration, Liability Number of shares authorized to be repurchased (in shares) Share Repurchase Program, Authorized, Number of Shares Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Weighted Average Weighted Average [Member] Intangible amortization expense Amortization of Intangible Assets Deferred tax assets Deferred Income Tax Assets, Net Deferred rent Deferred Rent Credit, Noncurrent Revolving Credit Facility Revolving Credit Facility [Member] Arrangement Duration Trading Arrangement Duration Other Other Sundry Liabilities, Noncurrent Derivative, gain (loss), statement of income or comprehensive income flag Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Computer and communications equipment Computer Equipment [Member] Segments [Axis] Segments [Axis] Fair value of expected net future cash flows from servicing recognized at commitment, net Fair Value of Expected Net Future Cash Flows from Servicing Recognized at Commitment, Net Servicing [Member] Servicing Payments for acquisitions, net of cash acquired and proceeds from divestitures Payments To Acquire Businesses, Net Of Cash Acquired And Proceeds From Divestiture Of Business, Net Of Cash Divested Payments To Acquire Businesses, Net Of Cash Acquired And Proceeds From Divestiture Of Business, Net Of Cash Divested Limited partner interest Limited Partner [Member] Local Phone Number Local Phone Number Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Arrangements and Non-arrangement Transactions Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Share price (in dollars per share) Share Price Other Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Other Item Compensation Share-Based Payment Arrangement [Text Block] Other intangible assets, net Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Excluding Goodwill Cash Business Combination, Recognized Asset Acquired, Cash and Cash Equivalent Assets: Assets [Abstract] Share-based payment arrangement, vesting period Restructuring And Related Cost, Share-Based Payment Arrangement, Vesting Period Restructuring And Related Cost, Share-Based Payment Arrangement, Vesting Period Credit Facility Credit Facility [Axis] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Debt Instrument Debt Instrument [Axis] Forfeited units (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Fair Value of Financial Assets and Liabilities Fair Value Disclosures [Text Block] Business Combination Business Combination [Line Items] Credit Facility Credit Facility [Domain] Receivable related to tax receivable agreement Tax Receivable Agreement, Asset, Noncurrent Tax Receivable Agreement, Asset, Noncurrent Derivative liability Derivative Liability, Current Treasury stock repurchases Treasury Stock, Value, Acquired, Cost Method BGC Holdings, L.P. B G C Holding Partnership Units [Member] BGC Partnership units. Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Right-of-use liabilities Operating Lease, Liability, Noncurrent Allocations of net income to limited partnership units and FPUs Distribution Made to Limited Partner, Cash Distributions Declared Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Abstract] Entity Registrant Name Entity Registrant Name Securities Financing Transaction Securities Financing Transaction [Line Items] Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Warehouse facility due May 5, 2026 Warehouse Facility Due May Five Two Thousand Twenty Six [Member] Warehouse Facility Due May Five Two Thousand Twenty Six Amortization of software development costs Capitalized Computer Software, Amortization Impairment, long-lived asset, held-for-use, statement of income or comprehensive income flag Impairment, Long-Lived Asset, Held-for-Use, Statement of Income or Comprehensive Income [Extensible Enumeration] Total Assets, Fair Value Disclosure Issued (in shares) Number of units, Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Granted Class of warrant or right, rights exchanged (in shares) Class Of Warrant Or Right, Rights Exchanged Class Of Warrant Or Right, Rights Exchanged Servicing asset at fair value, amount Servicing Asset at Fair Value, Amount Purchase of non-marketable investments Payments to acquire investments Payments to Acquire Equity Securities, FV-NI Partnership units (in shares) Incremental Common Shares Attributable To Limited Partnership Interests Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of limited partnership interests in BGC Holdings. Schedule of Debt Schedule of Debt [Table Text Block] Granted (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 Party, Type [Axis] Related and Nonrelated Parties [Axis] Fair value, asset, recurring basis, still held, unrealized gain (loss), statement of income or comprehensive income flag Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Repayments of long-term lines of credit Repayments of Long-Term Lines of Credit Type of Arrangement and Non-arrangement Transactions Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Restatement Determination Date: Restatement Determination Date [Axis] Guaranty liabilities Beginning balance Ending balance Financial guarantee liability Guaranty Liabilities Advances for principal and interest Advances For Principal And Interest Advances For Principal And Interest Name Trading Arrangement, Individual Name Loans held for sale, at fair value Loan, Held-for-Sale, Fair Value Disclosure Debt instrument face amount Debt Instrument, Face Amount Schedule of Activity Associated with Limited Partnership Units Share-Based Payment Arrangement, Activity [Table Text Block] Non-cash changes in acquisition related earn-outs Noncash Changes In Acquisition Earnouts Noncash Changes In Acquisition Earnouts Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Name Awards Close in Time to MNPI Disclosures, Individual Name Balance at the beginning of period (in dollars per share) Balance at the end of period (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Escrow funds amount Escrow Deposit Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Less: Comprehensive income (loss) attributable to noncontrolling interests, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest Number of authorized classes of common stock Number Of Authorized Classes Of Common Stock Number of authorized classes of common stock. Debt securities Non-marketable investments Alternative Investment Schedule of Grant of Conversion Rights Schedule of Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Grant Date Intrinsic Value [Table Text Block] Restricted stock units compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Reportable Segment Reportable Segment [Member] Reportable Segment Accumulated Other Comprehensive Income (Loss) AOCI Including Portion Attributable to Noncontrolling Interest [Member] Segments [Domain] Segments [Domain] Income Statement Location Statement of Income Location, Balance [Axis] Outside broker payable Outside Broker Payable Current Outside broker payable, current. Schedule of Revenue Remaining Performance Obligation Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Domain] Cost Basis Restructuring and Related Cost, Expected Cost [Abstract] Class of warrant or right, number of securities called by warrants or rights (in shares) Class of Warrant or Right, Number of Securities Called by Warrants or Rights Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment LPU redemption/exchange (in shares) Exchange Or Redemption For Limited Partnership Unit Exchange or redemption for limited partnership unit. Revenue Recognition Revenue [Policy Text Block] Senior Notes Senior Notes [Member] Mortgage Servicing Rights Servicing Asset at Amortized Cost, Balance [Roll Forward] All Executive Categories All Executive Categories [Member] Common stock value Common Stock, Value, Issued Employee Share-Based Payment Arrangement, Employee [Member] Fair Value, Assets And Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Commitments and contingencies (see Note 28) Commitments and Contingencies Business Combination Business Combination [Axis] Comprehensive income (loss), net of tax Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Maximum DB Cayman credit protection Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure New Accounting Pronouncements or Change in Accounting Principle [Table] Accounting Standards Update and Change in Accounting Principle [Table] Schedule of Revenue by Geographic Area Revenue from External Customers by Geographic Areas [Table Text Block] Noncontrolling Interests Noncontrolling Interest [Member] Other assets Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Other Assets Business combination recognized identifiable assets acquired and liabilities assumed other assets. Shares registered to be delivered pursuant to awards granted (in shares) Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Registered Share-based compensation arrangement by share-based payment award, number of shares registered. Related party transaction, annual compensation Related Party Transaction, Annual Compensation Related Party Transaction, Annual Compensation Concentration Risk Concentration Risk [Line Items] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Long-term debt term Long-Term Debt, Term Fully diluted earnings per share Fully diluted earnings per share: Earnings Per Share, Diluted [Abstract] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Hedging Designation Hedging Designation [Axis] Fair value, liability, recurring basis, still held, unrealized gain (loss), statement of income or comprehensive income flag Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Accounts payable, accrued expenses and other liabilities (see Note 26) Total Accounts Payable and Other Accrued Liabilities, Current California CALIFORNIA Derivative Contract Derivative Contract [Domain] Total Finite-Lived Intangible Asset, Expected Amortization, Expense Total amount of future amortization expense expected to be recognized following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life. All Individuals All Individuals [Member] Long-term Debt, Type Long-Term Debt, Type [Domain] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Purchases of fixed assets Payments to Acquire Property, Plant, and Equipment 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] 2025 Acquisitions 2025 Acquisitions [Member] 2025 Acquisitions Notional Value Notional Value Of Limited Partnership Units Eligible For Conversion Notional Value Of Limited Partnership Units Eligible For Conversion Schedule of Loans Held for Sale Schedule Of Loans Held For Sale [Table Text Block] Schedule of loans held for sale. Repurchase of Class A Common Stock Treasury Stock, Value, Acquired, Par Value Method Lessor, operating sublease, lease received Lessor, Operating Sublease, Lease Received Lessor, Operating Sublease, Lease Received Leasing and Other Commissions Leasing and Other Commissions Leasing And Other Commissions [Member] Leasing and other commissions. Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Related party transaction, upfront advance award, base for calculating number of grants in period Related Party Transaction, Upfront Advance Award, Base For Calculating Number Of Rights In Period Related Party Transaction, Upfront Advance Award, Base For Calculating Number Of Rights In Period Referral fee payment Related Party Transaction, Referral Fee, Percentage Related Party Transaction, Referral Fee, Percentage Geographical Geographical [Axis] 7.500% Senior Notes 7.500% Senior Notes Due January 12, 2029 [Member] 7.500% Senior Notes Due January 12, 2029 Lessee, Lease, Description Lessee, Lease, Description [Line Items] Non-contractual customers Customer-Related Intangible Assets [Member] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Partner Type of Partners' Capital Account, Name Partner Type of Partners' Capital Account, Name [Domain] Number of installments Class Of Warrant Or Right, Number Of Installments Class Of Warrant Or Right, Number Of Installments Related party transaction, rate Related Party Transaction, Rate Award Period One Award Period One [Member] Award Period One Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Concentration Risk Benchmark Concentration Risk Benchmark [Domain] Title of 12(b) Security Title of 12(b) Security Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Payroll taxes payable Accrued Payroll Taxes, Current Per share data: Earnings Per Share [Abstract] 2030 Lessee, Operating Lease, Liability, to be Paid, Year Five Non-compete agreements Noncompete Agreements [Member] Special servicing portfolio Special Servicing Portfolio Special servicing portfolio. Payments on acquisition earn-outs Payments of Merger Related Costs, Financing Activities Divestiture Goodwill, Written off Related to Sale of Business Unit Percentage of freddie Mac's liquidity requirement of outstanding principal of TAH loans serviced Percentage Of Liquidity Requirement Of Outstanding Principal Of Targeted Affordable Housing Loans Serviced Percentage of liquidity requirement of outstanding principal of targeted affordable housing loans serviced. Increase in deferred revenue Increase (Decrease) in Contract with Customer, Liability Non-Exchangeable Rights for Newmark Holdings PPSUs Non-Exchangeable Rights For Newmark Holdings PPSUs [Member] Non-Exchangeable Rights For Newmark Holdings PPSUs Advisory fee, total Related Party Transaction, Advisory Fee, Maximum Related Party Transaction, Advisory Fee, Maximum Payables to related parties Accounts Payable, Other, Current Restricted short-term investments Restricted short-term investments (greater than three months maturity) Restricted Investments, Current Right-of-use assets Right-of-Use Asset Increase (Decrease) Right-of-Use Asset Increase (Decrease) Number of units, Forfeited units/other (in shares) Number of Units, Forfeited units (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Forfeitures Newmark Holdings PPSU Newmark Holdings PPSU [Member] Newmark Holdings PPSU Fair Value, Assets And Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Treasury stock repurchases (in shares) Treasury stock repurchases (in shares) Share Repurchases, Total Number of Shares Repurchased (in shares) Treasury Stock, Shares, Acquired Management Services, Servicing Fees and Other Management Services, Servicing Fees and Other Management Services Servicing Fees And Other [Member] Management services, servicing fees and other. Award Timing Disclosures [Line Items] Servicing Asset at Amortized Cost [Line Items] Servicing Asset at Amortized Cost [Line Items] Fair Value, Measurement Frequency Measurement Frequency [Domain] Options to extend leases Lessee, Operating Lease, Renewal Term Number of Settled units (delivered shares) (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Exercised Borrowing of debt Proceeds from Issuance of Other Long-Term Debt Partner Type Partner Type [Axis] Amortization Servicing Asset at Amortized Cost, Amortization Stock Transactions and Unit Purchases Equity [Text Block] Interest rate during period Debt Instrument, Interest Rate During Period Loan sales—loans held for sale Proceeds from Sale, Loan, Mortgage, Held-for-Sale Net income (loss) available to common stockholders Net Income (Loss) Attributable to Parent Subsequent Event [Table] Subsequent Event [Table] Due from related party, percentage from sale Related Party Transaction, Due from (to) Related Party, Percentage From Sale Related Party Transaction, Due from (to) Related Party, Percentage From Sale Award vesting period Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Other sources of revenue Revenue Not from Contract with Customer Treasury stock repurchases Payments for Repurchase of Common Stock Adoption Date Trading Arrangement Adoption Date Base Rate Base Rate [Member] Remaining lease terms Lessee, Operating Lease, Term of Contract Income (loss) from operations Operating Income (Loss) Line of Credit Line of Credit [Member] Retained earnings Retained Earnings (Accumulated Deficit) Schedule of Share Repurchase Activity Class of Treasury Stock [Table Text Block] Schedule of Compensation Cost for Share-Based Payment Arrangements Share-Based Payment Arrangement, Cost by Plan [Table Text Block] 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] Capital Unit, Class Capital Unit, Class [Domain] Conversion percentage, tranche three Class Of Warrant Or Right, Tranche Three Class Of Warrant Or Right, Tranche Three Discount rates used in measuring fair value Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate Decrease (increase) Valuation Allowance for Impairment of Recognized Servicing Assets, Period Increase (Decrease) Earnings distributions to limited partnership interests and other noncontrolling interests Noncontrolling Interest, Earnings Distributions To Limited Partnership Interests And Other Noncontrolling Interest Noncontrolling Interest, Earnings Distributions To Limited Partnership Interests And Other Noncontrolling Interest Class of Stock Class of Stock [Axis] Subsequent Event Type 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] Payables and Accruals [Abstract] Other income (loss), net Other Nonoperating Income (Expense) Statement [Table] Statement [Table] Forfeited units Share-Based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Forfeited, Fair Value Share-Based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Forfeited, Fair Value Adjustments to reconcile net income to net cash provided by (used in) 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] Discount Rate Two Discount Rate Two [Member] Discount rate two. Total Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill Variable Rate Variable Rate [Domain] Deferred revenue Contract with Customer, Liability Escrow interest and placement fees Escrow Interest And Placement Fees Amount Escrow interest and placement fees amount. Organization and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Fannie Mae DUS or Freddie TAH Loans Fannie Mae D U S Or Freddie Targeted Affordable Housing Loans [Member] Fannie Mae DUS or Freddie targeted affordable housing loans. All Adjustments to Compensation All Adjustments to Compensation [Member] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Amendment Flag Amendment Flag Shares authorized to be delivered pursuant to awards granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized Transfers and Servicing [Abstract] Transfers and Servicing [Abstract] Treasury stock at cost: 95,557,475 and 86,125,782 shares of Class A common stock at March 31, 2026 and December 31, 2025, respectively Treasury Stock, Common, Value Termination Date Trading Arrangement Termination Date Exchangeable units (in shares) Exchangeable Units Exchangeable Units Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Related party transaction, termination notice, period Related Party Transaction, Termination Notice, Period Related Party Transaction, Termination Notice, Period Debt instrument, variable interest rate, type flag Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration] Tranche Three Share-Based Payment Arrangement, Tranche Three [Member] Weighted average discount rate Operating Lease, Weighted Average Discount Rate, Percent Business acquisition, aggregate revenue contribution Business Combination, Acquiree's Revenue since Acquisition Date, Actual Basic weighted-average shares of common stock outstanding (in shares) Common stock outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Warrants and rights outstanding Warrants and Rights Outstanding Granted Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Granted, Fair Value Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Granted, Fair Value Director Director [Member] Family Trust Howard W. Lutnick, Family Trust [Member] Howard W. Lutnick, Family Trust Related Party Transaction Related Party Transaction [Domain] Subsequent Events [Abstract] Subsequent Events [Abstract] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Primary Servicing Portfolio Primary Servicing Portfolio [Member] Primary Servicing Portfolio Number of shares vested and converted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested, Number of Shares Debt Disclosure [Abstract] Debt Disclosure [Abstract] Expenses: Costs and Expenses [Abstract] Exchangeable preferred limited partnership units (in shares) Other Ownership Interests, Units Exchangeable Other Ownership Interests, Units Exchangeable Exchangeable partnership units (in shares) Exchangeable Partnership Units Exchangeable Partnership Units 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 Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Consolidated Entities Consolidated Entities [Axis] Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Class of warrant or right, percentage receiving exchangeability Class Of Warrant Or Right, Percentage Receiving Exchangeability Class Of Warrant Or Right, Percentage Receiving Exchangeability Conversion percentage, tranche one Class Of Warrant Or Right, Tranche One Class Of Warrant Or Right, Tranche One Realized gain (loss) on marketable securities Equity Securities, FV-NI, Realized Gain (Loss) Annual compensation Related Party Transaction, Employee Compensation, Annual Compensation Related Party Transaction, Employee Compensation, Annual Compensation Mr. Robert Alvarado Mr. Robert Alvarado [Member] Mr. Robert Alvarado Lump sum payment, termination period Restructuring And Related Cost, Severance Costs, Lump Sum Payment, Termination Period Restructuring And Related Cost, Severance Costs, Lump Sum Payment, Termination Period Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Schedule of Non Current Other Assets Schedule of Other Assets, Noncurrent [Table Text Block] Newmark Holdings PSU Newmark Holdings PSU [Member] Newmark Holdings PSU Subsequent Events Subsequent Events [Text Block] Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Insider Trading Arrangements [Line Items] Newmark Holdings Units (in shares) Share Based Compensation Arrangement By Share Based Payment Award Units Redeemed Share based compensation arrangement by share based payment award units redeemed. Advisory fee, amounts received Related Party Transaction, Advisory Fee, Minimum Related Party Transaction, Advisory Fee, Minimum Rights for Previously Non-Exchangeable PSUs Rights For Previously Non-Exchangeable PSUs [Member] Rights For Previously Non-Exchangeable PSUs Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward] Total liabilities Liabilities Rate lock commitments Rate lock commitments Interest Rate Lock Commitments [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Class of warrant or right, percentage receiving exchangeability, pro rata Class Of Warrant Or Right, Percentage Receiving Exchangeability, Pro Rata Class Of Warrant Or Right, Percentage Receiving Exchangeability, Pro Rata Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Cantor Cantor [Member] Cantor. Trademark and trade names Trademark and trade names Trademarks and Trade Names [Member] Related party transaction, annual compensation, salary Related Party Transaction, Annual Compensation, Salary Related Party Transaction, Annual Compensation, Salary Variable Rate Variable Rate [Axis] Counterparty Name [Axis] Counterparty Name [Axis] Schedule of Activity Associated with Restricted Stock Units Share-Based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] Accrued compensation Accrued Compensation, Noncurrent Accrued compensation, noncurrent. Contractual customers Customer Contracts [Member] Entity Incorporation, State Entity Incorporation, State or Country Code Non-NEOs Non-NEOs [Member]