Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] Additional Premium Real Estate Investment Banking Services, Additional Premium [Member] Real Estate Investment Banking Services, Additional Premium Maximum Maximum [Member] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Title of 12(b) Security Title of 12(b) Security Subsequent Event Subsequent Event [Member] Servicing fees and other Servicing Fees And Other [Member] Servicing Fees And Other [Member] Cost Basis Reported Value Measurement [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. Net income (loss) for fully diluted shares Net income (loss) for fully diluted shares Net Income (Loss) Available to Common Stockholders, Diluted Beginning Balance Ending Balance Valuation Allowance for Impairment of Recognized Servicing Assets, Balance Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Adjustment to Compensation, Amount Adjustment to Compensation Amount Financial Instrument Financial Instrument [Axis] Repurchase of Class A Common Stock Treasury Stock, Value, Acquired, Par Value Method Schedule of Estimated Future Amortization Expense of Definite Life Intangible Assets Intangible Asset, Finite-Lived, and Capitalized Cost, Software to be Sold, Leased, or Marketed, Estimated Amortization Expense [Table Text Block] Revenue from External Customers by Products and Services [Table] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Table] Accrued compensation Employee-related Liabilities, Current Deferred tax asset Noncash Deferred Tax Asset Noncash Deferred Tax Asset Proceeds from the sale of limited partnership interests Proceeds from Partnership Contribution Derivative Instrument Derivative Instrument [Axis] Servicing asset at fair value, amount Servicing Asset at Fair Value, Amount 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 Measurement Frequency Measurement Frequency [Axis] Restricted cash Restricted Cash, Current, At Fair Value Restricted Cash, Current, At Fair Value Divestiture Goodwill, Divestiture Consolidated Entities Consolidated Entities [Axis] Shares repurchased price (in dollars per share) Average Price Paid per Share (in dollars per share) Shares Acquired, Average Cost Per Share Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Thereafter Lessee, Operating Lease, Liability, to be Paid, after Year Five Fixed assets, net Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment Employee loan amortization and other non-cash compensation expense Amortization of software development costs Amortization Leases [Abstract] Leases [Abstract] 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. Consolidated Entities Consolidated Entities [Domain] Related Party Transactions Related Party Transactions Disclosure [Text Block] Earnings and tax distributions to limited partnership interests and other noncontrolling interests Payments to Noncontrolling Interests Schedule of Cash and Cash Equivalents Schedule of Cash and Cash Equivalents [Table Text Block] Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share 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 Other intangible assets, net Net carrying amount Intangible Asset, Excluding Goodwill, after Accumulated Amortization Outstanding limited partnership units - unvested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Tranche One Share-Based Payment Arrangement, Tranche One [Member] Service Agreements Service Agreements [Member] 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. Schedule of Activity Associated with Limited Partnership Units Share-Based Payment Arrangement, Activity [Table Text Block] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount 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 Construction Loans Construction Loans [Member] Award Period Two Award Period Two [Member] Award Period Two Arrangements and Non-arrangement Transactions Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Number of reportable segments Number of Reportable Segments Total current liabilities Liabilities, Current Accrued compensation Increase (Decrease) in Accrued Salaries Beginning Balance Ending Balance Servicing Asset at Amortized Cost Newmark exchange shares (in shares) Incremental Common Shares Attributable To Exchange Incremental Common Shares Attributable To Exchange Derivative liability Derivative Liability, Current Non Distribution Earning Units Non Distribution Earning Units [Member] Non Distribution Earning Units [Member] Concentration Risk [Table] Concentration Risk [Table] Entity Address, City Entity Address, City or Town Number of conversion rights granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Interest Expense and Amortization of Debt Issue Costs Interest Expense, Debt [Abstract] Class of Financing Receivable [Domain] Class of Financing Receivable [Domain] Share-based Compensation Arrangement by Share-based Payment Award Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] 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. Loans, forgivable loans and other receivables from employees and partners, net Other Receivable, after Allowance for Credit Loss, Noncurrent 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 Definite life, net carrying amount Intangible Asset, Finite-Lived, after Accumulated Amortization Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Capital Unit, Class Capital Unit, Class [Domain] Level 2 Fair Value, Inputs, Level 2 [Member] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Payable related to tax receivable agreement Payable related to Tax Receivable Agreement Tax Receivable Agreement, Liability, Noncurrent Tax Receivable Agreement, Liability, Noncurrent Payments on acquisition earn-outs Payments of Merger Related Costs, Financing Activities Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] U.S. UNITED STATES Newmark Holdings Units Parent Company Parent Company [Member] Debt instrument, variable interest rate, type flag Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration] Loan sales—loans held for sale Proceeds from Sale, Loan, Mortgage, Held-for-Sale Subsequent Event Type Subsequent Event Type [Axis] Schedule of Capital Markets Summary Of Capital Markets [Table Text Block] Summary of gains from mortgage banking activities, net. Concentration Risk Type Concentration Risk Type [Axis] Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Schedule of Revenue by Segment Segment Reporting [Table Text Block] Newmark Holdings, L.P. Newmark Holdings Limited Partnership [Member] Newmark holdings limited partnership. Related Party, Type [Axis] Related and Nonrelated Parties [Axis] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Banking Regulation, Regulatory Capital Requirement, Compliance [Table] Principal payments on warehouse facilities Repayments of Lines of Credit 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 Capital Markets Capital Markets Capital Markets [Member] Capital Markets Non-contractual customers Customer-Related Intangible Assets [Member] Guarantor Obligations Guarantor Obligations [Line Items] Schedule of Minimum Lease Payments Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] Supplemental disclosure of non-cash operating, investing and financing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Accounts payable, accrued expenses and other liabilities Business Combination, Recognized Liability Assumed, Liability, Current Document Period End Date Document Period End Date Debt instrument face amount Debt Instrument, Face Amount 2027 Lessee, Operating Lease, Liability, to be Paid, Year Two Basic earnings per share Earnings Per Share, Basic [Abstract] Treasury stock at cost: 96,545,653 and 86,125,782 shares of Class A common stock at June 30, 2026 and December 31, 2025, respectively Treasury Stock, Common, Value Aggregate annual compensation, cash award granted Compensation Arrangement With Individual, Aggregate Annual Compensation, Cash Award Granted Compensation Arrangement With Individual, Aggregate Annual Compensation, Cash Award Granted Lessee, Lease, Description Lessee, Lease, Description [Line Items] Probability of meeting earnout and contingencies Measurement Input Expected Earnout And Contingencies Rate [Member] Measurement input expected earnout and contingencies rate. Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company Class B Common Stock Common Class B [Member] 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 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] Right-of-use liabilities Operating Lease, Liability, Current Convertible debt and other contract assets Convertible Debt And Other Contract Assets, Noncurrent Convertible Debt And Other Contract Assets, Noncurrent Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract] Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract] Trademark and trade names Trademark and trade names Trademarks and Trade Names [Member] Earnings Per Share and Weighted-Average Shares Outstanding Earnings Per Share [Text Block] Per share data: Earnings Per Share [Abstract] Document Fiscal Period Focus Document Fiscal Period Focus Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Product and Service, Revenue [Line Items] Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Number of Settled units (delivered shares) (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Exercised Schedule of Changes in the Carrying Amount of Mortgage Servicing Rights Servicing Asset at Amortized Cost [Table Text Block] Chief Operating Officer Chief Operating Officer [Member] Total liabilities Liabilities Trading Symbol Trading Symbol Partner Type Partner Type [Axis] Discount rate Measurement Input, Discount Rate [Member] Accumulated Other Comprehensive Income (Loss) AOCI Including Portion Attributable to Noncontrolling Interest [Member] Purchases of fixed assets Payments to Acquire Property, Plant, and Equipment Other Related Party Transactions With the CEO Other Related Party Transactions With the CEO [Member] Other Related Party Transactions With the CEO 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] Company Selected Measure Name Company Selected Measure Name Schedule of Restricted Cash Restrictions on Cash and Cash Equivalents [Table Text Block] Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] 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 Concentration Risk Concentration Risk [Line Items] Fully diluted earnings per share Fully diluted earnings per share: Earnings Per Share, Diluted [Abstract] Lines available Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases Restricted Stock Units Restricted Stock Award, Forfeitures [Abstract] Credit Facility Credit Facility [Domain] Depreciation and amortization Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction CASH FLOWS FROM OPERATING ACTIVITIES: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Financing receivable, nonaccrual Financing Receivable, Nonaccrual Dividends declared and paid per share of common stock (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] 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 Schedule of Other Current Assets Schedule of Other Current Assets [Table Text Block] Fair Value Restricted Cash, Fair Value [Abstract] Restricted Cash, Fair Value Type of Arrangement and Non-arrangement Transactions Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Increase in discount rate Percentage Of Increase In Discount Rate Of Servicing Rights Percentage of increase in discount rate of servicing rights. Receivable from related parties Increase (Decrease) in Accounts Receivable, Related Parties Other Other Intangible Assets [Member] 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. Operating lease payments Operating Lease, Payments Award Timing Predetermined Award Timing Predetermined [Flag] Distributions of income Temporary Equity, Distribution Of Income Temporary Equity, Distribution Of Income Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Restricted stock units compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Level 1 Fair Value, Inputs, Level 1 [Member] Grantee Status [Domain] Grantee Status [Domain] 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 Class of Financing Receivable [Axis] Class of Financing Receivable [Axis] Right-of-use liability Increase (Decrease) in Operating Lease Liability Outstanding borrower advances, reimbursement period Outstanding Borrower Advances To Investors, Reimbursement Period Outstanding Borrower Advances To Investors, Reimbursement Period Long-term debt, fair value Long-Term Debt, Fair Value Depreciation expense Depreciation Plan Name Plan Name [Domain] Vesting [Domain] Vesting [Domain] 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] Partner Type of Partners' Capital Account, Name Partner Type of Partners' Capital Account, Name [Domain] Right-of-use assets Operating Lease, Right-of-Use Asset Concentration Risk Type Concentration Risk Type [Domain] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Options to extend leases Lessee, Operating Lease, Renewal Term Total Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Debt Instrument, Name Debt Instrument, Name [Domain] Long-term line of credit Long-Term Line of Credit Expiration Date Trading Arrangement Expiration Date Aggregate annual compensation Compensation Arrangement With Individual, Aggregate Annual Compensation Compensation Arrangement With Individual, Aggregate Annual Compensation 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 Total equity Balance at beginning of period Balance at end of period Equity, Including Portion Attributable to Noncontrolling Interest Warehouse facility due May 4, 2027 Warehouse Facility Due May Four Two Thousand Twenty Seven [Member] Warehouse Facility Due May Four Two Thousand Twenty Seven Nonrelated Party Nonrelated Party [Member] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Limited Partnership Units Limited Partnership Units [Member] Limited partnership units. Receivables, net Business Combination, Recognized Asset Acquired, Receivable, Current CASH FLOWS FROM INVESTING ACTIVITIES: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Related Party Transaction Related Party Transaction [Axis] Deferred rent Deferred Rent Credit, Noncurrent Segments [Domain] Segments [Domain] Mortgage Banking [Abstract] Mortgage Banking [Abstract] Conversion of common stock (in shares) Conversion Of Common Stock Conversion of common stock. Debt Debt Disclosure [Text Block] Forfeited of shares (in shares) Shares Issued, Shares, Share-Based Payment Arrangement, Forfeited Total remaining draws on construction loans committed to fund Contractual Obligation Less: debt issue cost Debt Issuance Costs, Net Business Combination [Table] Business Combination [Table] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract] Maximum loss potential Financial Guarantee Liability, Maximum Potential Loss Financial Guarantee Liability, Maximum Potential Loss Cantor Credit Agreement Cantor Credit Agreement [Member] Total operating expenses Costs and Expenses Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Dividends to common stockholders Dividends, Common Stock, Cash Total stockholders’ equity Equity, Attributable to Parent Assets: Assets [Abstract] Fair Value, Measurements, Nonrecurring Fair Value, Nonrecurring [Member] Fees to related parties Professional and consulting fees Professional Fees Insider Trading Policies and Procedures [Line Items] Measurement period and currency translation adjustments Goodwill, Measurement Period Adjustment Accounts Payable, Accrued Expenses and Other Liabilities Accounts Payable and Accrued Liabilities Disclosure [Text Block] Allowance for doubtful accounts Accounts Receivable, Allowance for Credit Loss, Current Software development costs capitalized Property, Plant, and Equipment, before Accumulated Depreciation, Addition 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. Liabilities, Unobservable Input Reconciliation: Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Deferred tax provision (benefit) Deferred Income Tax Expense (Benefit) Interest expense, net Interest expense, net Interest Income (Expense), Nonoperating Partnership interest in investment, percentage Partnership Interest In Investment, Percentage Partnership Interest In Investment, Percentage 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 Monthly payment on sublease Lessor, Operating Sublease, Lease Payment Lessor, Operating Sublease, Lease Payment 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 Schedule of Changes in Carrying Amount of Goodwill Goodwill [Table Text Block] Entity Central Index Key Entity Central Index Key Accumulated depreciation and amortization Property, Plant, and Equipment, Accumulated Depreciation, Depletion, and Amortization Additional paid-in capital Additional Paid in Capital, Common Stock Schedule of Guarantor Obligations [Table] Guarantor Obligation [Table] Equity [Abstract] Equity [Abstract] 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] Mr. Merkel Executive Vice President [Member] Less: Comprehensive income (loss) attributable to noncontrolling interests, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest Other Stockholders' Equity, Other Tax Receivable Agreement liability Noncash Tax Receivable Agreement, Liability Noncash Tax Receivable Agreement, Liability 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. Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Axis] 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 Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Variable Rate Variable Rate [Domain] All Individuals All Individuals [Member] Ancillary fees Ancillary Fee Income Generated by Servicing Financial Assets, Amount Outstanding borrower advances Outstanding Borrower Advances To Investors Outstanding borrower advances to investors. Schedule of Revenue by Geographic Area Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue [Table Text Block] Assets, Unobservable Input Reconciliation: Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Cost not yet recognized, period for recognition Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Contingent consideration Business Combination, Contingent Consideration, Liability, Noncurrent Limited partnership units exchange ratio Limited Partnership Units Exchange Ratio Limited partnership units exchange ratio. Statement Statement [Line Items] Total assets Total assets Assets Defined Benefit Plan [Table] Defined Benefit Plan [Table] Lessee, Operating Lease, Liability, Payment, Due Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract] Fair Value Amount Fair Value Amount [Roll Forward] Fair Value Amount [Roll Forward] Realized gain (loss) on marketable securities Equity Securities, FV-NI, Realized Gain (Loss) Compensation Share-Based Payment Arrangement [Text Block] PEO PEO [Member] Capital and Liquidity Requirements Broker-Dealer Disclosure [Text Block] Other long-term liabilities (see Note 26) Total Other Liabilities, Noncurrent Goodwill Beginning balance Ending balance Goodwill Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Retained Earnings Retained Earnings [Member] Right-of-use liabilities Operating Lease, Liability, Noncurrent Operating expenses Operating Expenses Restricted cash and short-term investments Restricted Cash And Investments, Current, At Fair Value Restricted Cash And Investments, Current, At Fair Value Revolving Credit Facility Revolving Credit Facility [Member] Lease impairment Operating Lease, Impairment Loss Software, including software development costs Software, In-Development, Internally Developed, and Purchased [Member] Increase (Decrease) in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] 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 Award Timing Disclosures [Line Items] Fully diluted earnings per share (in dollars per share) Earnings Per Share, Diluted 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 Intangible amortization expense Intangible Asset, Finite-Lived, Amortization Expense Proceeds from long-term lines of credit Proceeds from Long-Term Lines of Credit Additions Servicing Asset at Amortized Cost, Additions Brokers and Dealers [Abstract] Broker-Dealer [Abstract] Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] Revenues from contracts with customers: Mortgage Brokerage and Debt Placement Revenue from Contract with Customer, Excluding Assessed Tax Committed Lines Committed Lines [Member] Committed lines. Repayment of debt Repayments of Other Long-Term Debt 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 Assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Loans, forgivable loans and other receivables from employees and partners, net Increase (Decrease) in Due from Employee, Current Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] 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, advance award (in shares) Class Of Warrant Or Right, Advance Award Class Of Warrant Or Right, Advance Award Purchase of restricted short-term investments Payments to Acquire Short-Term Investments Gross amount Intangible Asset, Excluding Goodwill, before Accumulated Amortization 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. 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. 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 Escrow funds amount Escrow Deposit Gain (loss) recognized in income for derivatives Derivative, Gain (Loss) on Derivative, Net Income (loss) from operations Operating Income (Loss) Revenue, remaining performance obligation, amount Revenue, Remaining Performance Obligation, Amount Warrants and rights outstanding Warrants and Rights Outstanding Allocated Revenue Real Estate Investment Banking Services, Allocated Revenue [Member] Real Estate Investment Banking Services, Allocated Revenue Limited Partnership Interests in Newmark Holdings and BGC Holdings Partners' Capital Notes Disclosure [Text Block] Related Party Transaction Related Party Transaction [Domain] Acquisitions Business Combination [Text Block] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Leasehold improvements, furniture and fixtures, and other fixed assets Lease Hold Improvements And Other Fixed Assets [Member] Leasehold improvements and other fixed assets. Shares purchased for award (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Purchased for Award Common stock, issued (in shares) Common Stock, Shares, Issued Opening Balance Closing Balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Class of warrant or right percentage Class Of Warrant Or Right Percentage Class Of Warrant Or Right Percentage Servicing Asset at Amortized Cost [Line Items] Servicing Asset at Amortized Cost [Line Items] Other Current Assets and Other Assets Other Assets Disclosure [Text Block] Forward Sales Contracts Forward Contracts [Member] Receivables, net Increase (Decrease) in Accounts Receivable Product and Service [Domain] Product and Service [Domain] Class of Stock Class of Stock [Line Items] California CALIFORNIA Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Uncommitted Lines Uncommitted Lines [Member] Uncommitted lines. Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] Number of employees Related Party Transaction, Number Of Sons Related Party Transaction, Number Of Sons Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Limited partner interest Limited Partner [Member] Unrealized gains (losses) outstanding Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss) Liabilities Liabilities, Total [Member] Cash payment Class Of Warrant Or Right, Cash Waived Class Of Warrant Or Right, Cash Waived Liquidation value of loans outstanding Liquidation Value Of Loans Outstanding Liquidation Value Of Loans Outstanding 2028 Lessee, Operating Lease, Liability, to be Paid, Year Three Termination Date Trading Arrangement Termination Date Number of tranches Class Of Warrant Or Right, Number Of Tranches Class Of Warrant Or Right, Number Of Tranches Subsequent Events [Abstract] Subsequent Events [Abstract] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Higher borrowing capacity option Line Of Credit Facility, Accordion Feature, Higher Borrowing Capacity Option Line Of Credit Facility, Accordion Feature, Higher Borrowing Capacity Option Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] 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] Derivative assets Derivative Asset, Current Fair Value as of Grant Date Award Grant Date Fair Value Fannie Mae repurchase agreement, open maturity Fannie Mae Repurchase Agreement Open Maturity [Member] Fannie Mae repurchase agreement, open maturity. Increase (Decrease) in Temporary Equity Increase (Decrease) in Temporary Equity [Roll Forward] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] 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 Arrangement Duration Trading Arrangement Duration Investment sales Investment Advice [Member] Remaining from debt repurchase authorization Debt Instrument, Debt Repurchase Program Remaining Authorized Repurchase Amount Debt Instrument, Debt Repurchase Program Remaining Authorized Repurchase Amount Payout period for post-termination awards Post Termination Award Payout Period Post termination award payout period. Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Cash paid during the period for: Cash Paid During Period For [Abstract] Cash paid during period for. 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Enumeration] Common stock, authorized (in shares) Common Stock, Shares Authorized Concentrations of Credit Risk Concentration Risk Disclosure [Text Block] Schedule of Activity Associated with Restricted Stock Units Share-Based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] Exercise Price Award Exercise Price Fair Value, Recurring Fair Value, Recurring [Member] Document Quarterly Report Document Quarterly Report Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Texas TEXAS Warehouse facilities collateralized by U.S. Government Sponsored Enterprises Outstanding draws Warehouse Agreement Borrowings Provision (reversal) for expected credit losses Provision (Reversal) For Risk Sharing Obligations And Settlement Provision (Reversal) For Risk Sharing Obligations And Settlement Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Mortgage brokerage and debt placement Mortgage Brokerage and Debt Placement Mortgage Brokerage And Debt Placement [Member] Mortgage Brokerage And Debt Placement Equity Component Equity Component [Domain] Measurement Input Type Measurement Input Type [Domain] 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 Adoption Date Trading Arrangement Adoption Date Securities Financing Transaction Securities Financing Transaction [Line Items] Counterparty Name [Domain] Counterparty Name [Domain] Mortgage servicing rights, net Net Balance Servicing Asset Newmark Holdings NPSUs Newmark Holdings NPSUs [Member] Newmark Holdings NPSUs Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Accounting Policies [Abstract] Accounting Policies [Abstract] Dividends to stockholders Payments of Capital Distribution Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Operating lease, liability Present value of lease liability Operating Lease, Liability Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Schedule of Company Lines Available and Borrowings Outstanding Schedule of Line of Credit Facilities [Table Text Block] Number of shares authorized to be repurchased (in shares) Share Repurchase Program, Authorized, Number of Shares Derivative Instruments, Gain (Loss) Derivative Instruments, Gain (Loss) [Line Items] Business Combination Business Combination [Domain] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Restricted Stock Units Restricted Stock Units (RSUs) [Member] Weighted Average Weighted Average [Member] 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 All Adjustments to Compensation All Adjustments to Compensation [Member] Other Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Other Item Business Combination Business Combination [Axis] Net cash provided by (used in) operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Income Statement [Abstract] Income Statement [Abstract] Document Transition Report Document Transition Report 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 Deferred tax assets Deferred Income Tax Assets, Net Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Receivable related to tax receivable agreement Tax Receivable Agreement, Asset, Noncurrent Tax Receivable Agreement, Asset, Noncurrent City Area Code City Area Code BGC Holdings, L.P. B G C Holding Partnership Units [Member] BGC Partnership units. Document Information [Table] Document Information [Table] Subsequent Events Subsequent Events [Text Block] Name Forgone Recovery, Individual Name Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Entity [Domain] Entity [Domain] Limited partnership units amortization RSU amortization Employee Benefits and Share-Based Compensation Schedule of Units Redeemed Share-Based Payment Arrangement, Outstanding Award, Activity, Excluding Option [Table Text Block] Other assets Increase (Decrease) in Other Operating Assets Issuance of Class A common stock for Newmark RSUs (in shares) Stock Issued During Period, Shares, New Issues Accounts payable, accrued expenses and other liabilities (see Note 26) Total Accounts Payable and Other Accrued Liabilities, Current Class of warrant or right, rights exchanged (in shares) Class Of Warrant Or Right, Rights Exchanged Class Of Warrant Or Right, Rights Exchanged Contractual customers Customer Contracts [Member] Compensation expense (benefit) Total compensation expense Share-Based Payment Arrangement, Expense Measurement Basis Measurement Basis [Axis] 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. Additional share authorized (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized Unit exercised during period (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period Acquisitions Goodwill, Acquired During Period 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 Deferred revenue, revenue recognized Contract with Customer, Liability, Revenue Recognized Subsequent Event Type Subsequent Event Type [Domain] Payables and Accruals [Abstract] Corporate taxes payable Taxes Payable, Current 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 Cash Business Combination, Recognized Asset Acquired, Cash and Cash Equivalent Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Rent and other deposits Deposit Assets Advances for principal and interest Advances For Principal And Interest Advances For Principal And Interest Entity Current Reporting Status Entity Current Reporting Status Net cash provided by (used in) financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Mortgage servicing right recognized Fees and Commissions, Mortgage Banking and Servicing Non-cash changes in acquisition related earn-outs Noncash Changes In Acquisition Earnouts Noncash Changes In Acquisition Earnouts Payables to related parties Increase (Decrease) in Accounts Payable, Related Parties 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] Fixed assets, net Total, net Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization Financial Instruments Financial Instruments [Domain] Number of authorized classes of common stock Number Of Authorized Classes Of Common Stock Number of authorized classes of common stock. Derivative asset Derivative Asset Intangible Asset, Finite-Lived, Class Intangible Asset, Finite-Lived, Class [Axis] Allowance for doubtful accounts, period (decrease) increase Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease) Goodwill and Other Intangible Assets, Net Intangible Asset and Goodwill [Text Block] Underlying Securities Award Underlying Securities Amount Fair Value Estimate of Fair Value Measurement [Member] Revenues from Contracts with Customers Revenue from Contract with Customer [Text Block] Cantor purchase of Cantor units from Newmark Holdings upon redemption/ exchange of FPUs Stock Issued During Period, Value, New Issues Prepaid expenses Prepaid Expense, Current Reportable Segment Reportable Segment [Member] Reportable Segment Weighted average discount rate Operating Lease, Weighted Average Discount Rate, Percent Outside broker payable Outside Broker Payable, Current Outside broker payable, current. Shares available for future awards (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Income allocation Temporary Equity, Net Income Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Table] Computer and communications equipment Computer Equipment [Member] Guarantees [Abstract] Guarantees [Abstract] Business acquisition, aggregate revenue contribution Business Combination, Acquiree's Revenue since Acquisition Date, Actual Contingent consideration Business Combination, Contingent Consideration, Liability, Current Other current assets (see Note 17) Total Other Assets, Current Michael J. Rispoli Chief Financial Officer [Member] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Opening Balance Closing Balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] LPU redemption/exchange (in shares) Exchange Or Redemption For Limited Partnership Unit Exchange or redemption for limited partnership unit. Current Fiscal Year End Date Current Fiscal Year End Date Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Mortgage Servicing Rights Servicing Asset at Amortized Cost, Balance [Roll Forward] Issuance and other Temporary Equity, Stock Issued During Period, Value, New Issues Aggregated repurchased (in shares) Stock Repurchased During Period, Shares 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] Dividends declared per share of common stock (in dollars per share) Common Stock, Dividends, Per Share, Declared Entity File Number Entity File Number Servicing fees Contractually Specified Servicing Fees, 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] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Measure: Measure [Axis] Investments Equity Method Investments and Joint Ventures Disclosure [Text Block] Fair value of non-vested Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested Treasury stock, issued (in shares) Treasury Stock, Common, Shares 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. Equity Components Equity Components [Axis] Related party transaction, annual compensation Related Party Transaction, Annual Compensation Related Party Transaction, Annual Compensation Related Party Related Party [Member] Class A Common Stock Common Class A [Member] Entity Interactive Data Current Entity Interactive Data Current Variable Rate Variable Rate [Axis] Less: Net income (loss) attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Exchange of Cantor Units for Newmark Class A common stock (in shares) Stock Issued During Period, Shares, Conversion of Units Entity Small Business Entity Small Business Comprehensive income (loss) available to common stockholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Shares withheld for tax withholding obligation (in shares) Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Property, Plant, and Equipment Property, Plant, and Equipment [Line Items] Weighted- Average Remaining Life (Years) Intangible Asset, Finite-Lived, Acquired, Weighted-Average Amortization Period Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Other assets (see Note 17) Total Other Assets, Noncurrent Document Type Document Type Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] 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. Other Other Assets, Miscellaneous, Current Subsequent Event Subsequent Event [Line Items] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Borrowings of long-term debt Proceeds from Issuance of Long-Term Debt Local Phone Number Local Phone Number Guaranty liabilities Beginning balance Ending balance Financial guarantee liability Guaranty Liabilities Income (loss) before income taxes and noncontrolling interests Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Commitments and contingencies (see Note 28) Commitments and Contingencies 2025 Acquisitions 2025 Acquisitions [Member] 2025 Acquisitions Schedule of Other Long-term Liabilities Other Noncurrent Liabilities [Table Text Block] Total, cost Property, Plant, and Equipment, before Accumulated Depreciation, Depletion, and Amortization Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] 2030 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Four New Accounting Pronouncements or Change in Accounting Principle [Table] Accounting Standards Update and Change in Accounting Principle [Table] 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. Executive Category: Executive Category [Axis] 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. 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] Counterparty Name [Axis] Counterparty Name [Axis] Liabilities, Redeemable Partnership Interests, and Equity: Liabilities and Equity [Abstract] 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 (as percent) Related Party Transaction, Referral Fee, Percentage Related Party Transaction, Referral Fee, Percentage 7.500% Senior Notes 7.500% Senior Notes Due January 12, 2029 [Member] 7.500% Senior Notes Due January 12, 2029 Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Acquisitions from 2022 through 2025 Acquisitions From Two Thousand Twenty Two Through Two Thousand Twenty Six [Member] Acquisitions from 2022 through 2026. Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Number of installments Class Of Warrant Or Right, Number Of Installments Class Of Warrant Or Right, Number Of Installments PEO Name PEO Name Award Period One Award Period One [Member] Award Period One Liabilities: Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Taxes Income Tax Paid, before Refund Received Property, Plant and Equipment, Type [Axis] Long-Lived Asset, Class [Axis] Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Contingent consideration liability, measurement input Business Combination, Contingent Consideration, Liability, Measurement Input Allocations Business Combination, Recognized Asset Acquired, Asset [Abstract] Revenue Recognition Revenue [Policy Text Block] Special servicing portfolio Special Servicing Portfolio Special servicing portfolio. Allocations of net income to limited partnership units and FPUs Distribution Made to Limited Partner, Cash Distributions Declared Entity Incorporation, State Entity Incorporation, State or Country Code Base Rate Base Rate [Member] Proceeds from maturity of restricted short-term investments Proceeds from Maturities, Prepayments and Calls of Short-Term Investments Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Additions Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases 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. Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] 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] Non-Exchangeable Rights for Newmark Holdings PPSUs Non-Exchangeable Rights For Newmark Holdings PPSUs [Member] Non-Exchangeable Rights For Newmark Holdings PPSUs Organization and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Comprehensive income (loss), net of tax Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Advisory fee, total Related Party Transaction, Advisory Fee, Maximum Related Party Transaction, Advisory Fee, Maximum Fair Value, Measurement Frequency Measurement Frequency [Domain] Debt Instrument Debt Instrument [Axis] Subsequent Event [Table] Subsequent Event [Table] Right-of-use assets Right-of-Use Asset Increase (Decrease) Right-of-Use Asset Increase (Decrease) Total compensation and employee benefits Labor and related expense Labor and Related Expense Rent expense Lease, Cost Newmark Holdings PPSU Newmark Holdings PPSU [Member] Newmark Holdings PPSU Schedule of Fair Value of Derivative Contracts Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Basic earnings per share (in dollars per share) Earnings Per Share, Basic Measurement Input Type Measurement Input Type [Axis] 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. Total current assets Assets, Current Insider Trading Arrangements [Line Items] Payroll taxes payable Accrued Payroll Taxes, Current Long-term debt Long-Term Debt, Excluding Current Maturities Short-term lease expense Short-Term Lease, Cost Deferred financing costs Payments of Financing Costs Receivables, net Accounts Receivable, after Allowance for Credit Loss, Current Schedule of Share Repurchase Activity Class of Treasury Stock [Table Text Block] Details for the Senior Notes Senior Notes [Abstract] 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] 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] Capital Units by Class Capital Units by Class [Axis] Redeemable partnership interests Balance at beginning of period: Balance at end of period Temporary Equity, Including Noncontrolling Interest 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 Contingent consideration Contingent consideration Business Combination, Contingent Consideration, Liability Fair Value Measurement Fair Value Measurement [Domain] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Cover [Abstract] U.K. UNITED KINGDOM Borrowing of debt Proceeds from Issuance of Other Long-Term Debt Concentration risk percentage Concentration Risk, Percentage Amount of capital in excess of aggregate regulatory requirements Banking Regulation, Total Risk-Based Capital, Excess, Actual Equity Awards Adjustments Equity Awards Adjustments [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Plan Name Plan Name [Axis] Conversion percentage, tranche three Class Of Warrant Or Right, Tranche Three Class Of Warrant Or Right, Tranche Three 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 General partners' capital account, units outstanding (in shares) General Partners' Capital Account, Units Outstanding Compliance with Regulatory Capital Requirements under Banking Regulations Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Schedule of Compensation Cost for Share-Based Payment Arrangements Share-Based Payment Arrangement, Cost by Plan [Table Text Block] Other income (loss), net Other Nonoperating Income (Expense) 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] Equity: Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Number of shares vested and converted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested, Number of Shares Purchase of non-marketable investments Payments to Acquire Investments 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 Schedule of Changes in Carrying Amount of Redeemable Partnership Interest Redeemable Noncontrolling Interest [Table Text Block] Operating, administrative and other General and Administrative Expense Discount Rate Two Discount Rate Two [Member] Discount rate two. Escrow interest and placement fees Escrow Interest And Placement Fees Amount Escrow interest and placement fees amount. 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. Hedging Designation Hedging Designation [Domain] FPU's Founding Working Partner Units [Member] Founding Working Partner Units Class of Stock Class of Stock [Domain] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Exchangeable units (in shares) Exchangeable Units Exchangeable Units Derivative, gain (loss), statement of income or comprehensive income flag Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Related party transaction, termination notice, period Related Party Transaction, Termination Notice, Period Related Party Transaction, Termination Notice, Period Income Taxes Income Tax Disclosure [Text Block] 2030 Lessee, Operating Lease, Liability, to be Paid, Year Five 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] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] 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 Total Business combination, consideration transferred Business Combination, Consideration Transferred Entity Filer Category Entity Filer Category Director Director [Member] Primary Servicing Portfolio Primary Servicing Portfolio [Member] Primary Servicing Portfolio Exchangeable preferred limited partnership units (in shares) Other Ownership Interests, Units Exchangeable Other Ownership Interests, Units Exchangeable Founding partner interest General Partner [Member] Exchangeable partnership units (in shares) Exchangeable Partnership Units Exchangeable Partnership Units Concentration Risk Benchmark Concentration Risk Benchmark [Domain] Operating lease, liability, current, statement of financial position flag Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Not Designated as Hedging Instrument Not Designated as Hedging Instrument [Member] Beginning balance (in shares) Ending balance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding, Number Equity Method Investments and Joint Ventures [Abstract] Equity Method Investments and Joint Ventures [Abstract] Unrealized gains (losses) outstanding Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) 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 Annual compensation Related Party Transaction, Employee Compensation, Annual Compensation Related Party Transaction, Employee Compensation, Annual Compensation 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] 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 Schedule of Stock by Class [Table] Stock, Class of Stock [Table] Consolidated net income (loss) Consolidated net income (loss) Consolidated net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Current assets: Assets, Current [Abstract] Derivative liability Derivative Liability Senior Notes Senior Notes [Member] Entity Address, Street Entity Address, Address Line One Right-of-use assets and liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability 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 Provision (benefit) for income taxes Income Tax Expense (Benefit) Newmark Holdings PSU Newmark Holdings PSU [Member] Newmark Holdings PSU 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 Risks and Uncertainties [Abstract] Risks and Uncertainties [Abstract] Consolidation Consolidation, Policy [Policy Text Block] 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 Present value of expected payments Valuation Technique, Discounted Cash Flow [Member] Statement [Table] Statement [Table] Tranche Two Share-Based Payment Arrangement, Tranche Two [Member] Cantor Cantor [Member] Cantor. Schedule of Revenue Remaining Performance Obligation Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Related party transaction, annual compensation, salary Related Party Transaction, Annual Compensation, Salary Related Party Transaction, Annual Compensation, Salary Federal Funds Rate Fed Funds Effective Rate Overnight Index Swap Rate [Member] Loans held for sale, at fair value Loan, Held-for-Sale, Fair Value Disclosure Accrued compensation Accrued Compensation, Noncurrent Accrued compensation, noncurrent. Long-term debt term Long-Term Debt, Term 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 Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract]