Related Party Transactions [Abstract] Related Party Transactions [Abstract] Document Type Document Type Level 3 Fair Value, Inputs, Level 3 [Member] Adjustments to Additional Paid in Capital, Other Adjustments to Additional Paid in Capital, Other APIC, Share-based Payment Arrangement, Increase for Cost Recognition APIC, Share-based Payment Arrangement, Increase for Cost Recognition Total current liabilities Liabilities, Current Variable Interest Entity, Classification Variable Interest Entity, Classification [Domain] Other current assets Increase (Decrease) in Other Current Assets Treasury stock, shares Treasury Stock, Shares Granted (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Vested (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Other Revenue, Net Other Revenue, Net Other Revenue, Net Security Exchange Name Security Exchange Name Target [Domain] Target [Domain] [Domain] for Target [Axis] Dividends payable, date to be paid Dividends Payable, Date to be Paid Accrued stock repurchases Accrued Stock Repurchases Accrued Stock Repurchases Total revenues Revenues Schedule of Investments [Line Items] Schedule of Investments [Line Items] Gross Unrealized Losses Debt Securities, Trading, Unrealized Loss Diluted (shares) Weighted average shares outstanding - diluted (shares) Weighted Average Number of Shares Outstanding, Diluted Issuance of restricted stock, net of forfeitures, shares Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Document And Entity Information [Abstract] Document And Entity Information [Abstract] Document and entity information. Cost Debt Securities, Trading, Amortized Cost CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Schedule of Investments [Table] Schedule of Investments [Table] Canada CANADA Asset Management [Member] Asset Management [Member] Property and equipment, net of accumulated depreciation of $8,099 and $8,056 Property, Plant and Equipment, Net AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] Schedule Of Available For Sale Securities [Line Items] Debt Securities, Available-for-sale [Line Items] Total assets Segment assets Assets Australia AUSTRALIA Entity Address, State or Province Entity Address, State or Province Service period of mutual fund share incentive award Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Subsequent Event [Member] Subsequent Event [Member] Subsequent Event, Description Subsequent Event, Description Purchases of treasury stock, shares Purchases of treasury stock, shares Treasury Stock, Shares, Acquired Scenario [Domain] Scenario [Domain] Computation of Basic and Diluted Shares Earnings Per Share Reconciliation [Abstract] Income taxes payable Accrued Income Taxes, Current Restricted Stock Restricted Shares Subject Only to a Service Condition Restricted Stock [Member] Operating Lease, Impairment Loss Operating Lease, Impairment Loss Net change in unrealized (appreciation) depreciation on investments Trading Securities, Change in Unrealized Holding Gain (Loss) Accounts receivable Increase (Decrease) in Accounts Receivable Current liabilities: Liabilities, Current [Abstract] stock repurchase authorization - subsequent event stock repurchase authorization - subsequent event stock repurchase authorization - authorization subsequent to financial statement date Forfeited (dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Contract with Customer, Sales Channel [Axis] Contract with Customer, Sales Channel [Axis] SEGMENT REPORTING Segment Reporting Disclosure [Text Block] Equity [Abstract] Equity [Abstract] Net intersegment revenues Net Intersegment Revenues Net intersegment revenues. Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Commitments and contingencies Commitments and Contingencies Professional services Professional Fees Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Schedule Of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Consolidation, Variable Interest Entity, Policy [Policy Text Block] Consolidation, Variable Interest Entity, Policy [Policy Text Block] Stock Repurchase Program, Remaining Authorized Repurchase Amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Consolidation Items [Domain] Consolidation Items [Domain] Money market funds Money Market Funds [Member] Unobservable input -book value multiple - weighted average Unobservable input -book value multiple - weighted average Unobservable input -book value multiple - weighted average Earnings per share: Earnings Per Share, Basic and Diluted [Abstract] Assets Under Management Assets under Management, Carrying Amount Amount at Risk Risk Of Loss The risk of loss on Investment in VIE. Investments Measured at NAV Fair Value Measured at Net Asset Value Per Share [Member] Investments carried at fair value, unrealized loss Investments carried at fair value, unrealized loss Investments carried at fair value, unrealized loss Remaining unrecognized compensation cost Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Treasury Stock [Member] Treasury Stock [Member] Segments [Axis] Segments [Axis] Private equity Private Equity Investments [Member] Private Equity Investments [Member] Treasury stock, at cost - 2,317,449 shares at March 31, 2021; 2,173,559 shares at December 31, 2020 Treasury Stock, Value Product and Service [Domain] Product and Service [Domain] Vested (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 Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Westwood Hospitality Fund I LLC [Member] Westwood Hospitality Fund I LLC [Member] Westwood Hospitality Fund I LLC [Member] Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Operating Income (Loss) Operating Income (Loss) Entity Small Business Entity Small Business Goodwill Goodwill Segment [Domain] Segments [Domain] Statement [Line Items] Statement [Line Items] Revenue from Contract with Customer, Excluding Assessed Tax Revenue from Contract with Customer, Excluding Assessed Tax Disaggregation of Revenue [Table Text Block] Disaggregation of Revenue [Table Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Basic (dollars per share) Earnings Per Share, Basic Dividends declared per share (dollars per share) Common Stock, Dividends, Per Share, Declared Amendment Flag Amendment Flag Investments in securities: Investments, Fair Value Disclosure [Abstract] Earnings Per Share, Policy [Policy Text Block] Earnings Per Share, Policy [Policy Text Block] Total comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Plan Name [Axis] Plan Name [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Mutual Fund Advisory [Member] Mutual Fund Advisory [Member] [Member] Mutual Fund Advisory [Member] [Member] Dividends payable Dividends Payable, Current Change in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Common stock, shares outstanding BALANCE, shares BALANCE, shares Common Stock, Shares, Outstanding Consolidation Items [Axis] Consolidation Items [Axis] Level 1 Fair Value, Inputs, Level 1 [Member] Entity Central Index Key Entity Central Index Key Private investment fund Private Equity Funds [Member] Liabilities, Noncurrent Liabilities, Noncurrent Plan Name [Domain] Plan Name [Domain] STOCKHOLDERS' EQUITY Stockholders' Equity Note Disclosure [Text Block] Gain (Loss) on Disposition of Assets Gain (Loss) on Disposition of Assets Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax Foreign Currency Translation Adjustment, Description Foreign Currency Translation Adjustment, Description Proceeds from Sale of Productive Assets Proceeds from Sale of Productive Assets Accounts receivable Accounts Receivable, after Allowance for Credit Loss, Current Contract with Customer, Sales Channel [Domain] Contract with Customer, Sales Channel [Domain] Long-term Investments Carried at Fair Value Long-term Investments Carried at Fair Value Long-term Investments Carried at Fair Value Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Equity Securities Equity Securities [Member] Total Expense Recorded for Stock Based Compensation Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Variable Interest Entity, Consolidated, Assets, Noncurrent Variable Interest Entity, Consolidated, Assets, Noncurrent Tax Adjustments, Settlements, and Unusual Provisions Tax Adjustments, Settlements, and Unusual Provisions Institutional Institutional [Member] Institutional. Total current assets Assets, Current Net Change in Cash and Cash Equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Treasury Stock, Value, Acquired, Par Value Method Treasury Stock, Value, Acquired, Par Value Method Debt Securities, Trading, Gain (Loss) [Abstract] Debt Securities, Trading, Gain (Loss) [Abstract] Net income Net Income (Loss) Attributable to Parent Net Income (Loss) Attributable to Parent Common Stock [Member] Common Stock [Member] Current Assets: Assets, Current [Abstract] Title of 12(b) Security Title of 12(b) Security Leases [Abstract] Leases [Abstract] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Estimated Fair Value Private Equity Securities, FV-NI Status and Changes in Restricted Stock Grants that Subject to Service Condition Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] Product and Service [Axis] Product and Service [Axis] Net interest and dividend revenue Investment Income, Net UCITS Fund Undertaking For Collective Investment In Transferable Securities [Member] Undertaking for collective investment in transferable securities. Scenario [Axis] Scenario [Axis] Payments to Acquire Investments Payments to Acquire Investments Share Based Compensation Arrangement By Share Based Payment Award Available For Grant, Original Share Based Compensation Arrangement By Share Based Payment Award Available For Grant, Original Share Based Compensation Arrangement By Share Based Payment Award Available For Grant, Original Expense related to mutual fund share incentive awards Share-based Payment Arrangement, Expense Share-based Payment Arrangement, Expense Westwood Holdings Corporate, Non-Segment [Member] Total liabilities and stockholders' equity Liabilities and Equity Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Employee Benefit and Share-based Payment Arrangement, Noncash Expense [Abstract] Employee Benefit and Share-based Payment Arrangement, Noncash Expense [Abstract] Operating Lease, Liability, Noncurrent Operating Lease, Liability, Noncurrent Variable Interest Entities Variable Interest Entities [Axis] Stockholders' Equity: Stockholders' Equity Attributable to Parent [Abstract] Gross Unrealized Gains Equity Securities, FV-NI, Unrealized Gain Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] SUBSEQUENT EVENTS Subsequent Events [Text Block] REVENUES: Revenues [Abstract] Severance Costs Severance Costs LONG-TERM INCENTIVE COMPENSATION Compensation and Employee Benefit Plans [Text Block] Investments carried at fair value, unrealized gain Investments carried at fair value, unrealized gain Investments carried at fair value, unrealized gain VIE Variable Interest Entity [Member] Variable interest entity. Award Type Award Type [Axis] Treasury Stock Acquired, Average Cost Per Share Treasury Stock Acquired, Average Cost Per Share Income taxes payable Increase (Decrease) in Accrued Taxes Payable Trust performance-based Trust performance-based [Member] Trust performance-based Subsequent Events [Abstract] Subsequent Events [Abstract] Gross Unrealized Losses Equity Securities, FV-NI, Unrealized Loss RELATED PARTY TRANSACTIONS Related Party Transactions Disclosure [Text Block] EXPENSES: Costs and Expenses [Abstract] Treasury Stock, Common, Value Treasury Stock, Common, Value Stock Repurchased During Period, Value Stock Repurchased During Period, Value Geographical [Axis] Geographical [Axis] Debt Securities, Trading Investments in trading securities Debt Securities, Trading Retained Earnings [Member] Retained Earnings [Member] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Line Items] Subsequent Event [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period LEASES Lessee, Operating Leases [Text Block] Accrued purchase of property and equipment Capital Expenditures Incurred but Not yet Paid Weighted average shares outstanding: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Statement [Table] Statement [Table] Other current assets Other Assets, Current Performance-based fees [Member] performance fee [Member] performance fee [Member] Cash dividends paid Payments of Dividends Mutual Fund [Member] Mutual Fund [Member] GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill and Intangible Assets Disclosure [Text Block] Net fee revenues from external sources Revenue From External Sources Revenue From External Sources Total number of shares that may be issued under the stock based compensation Plan (including predecessor plans to the Plan) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Mutual Fund Share Incentive Awards Mutual Fund Share Incentive Awards [Member] Mutual Fund Share Incentive Awards Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block] Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block] Related Party Related Party [Domain] Share price Share Price Asia [Member] Asia [Member] Antidilutive Securities, Name Antidilutive Securities, Name [Domain] Retained earnings (accumulated deficit) Retained Earnings (Accumulated Deficit) Legal Entity Legal Entity [Axis] Purchases of treasury stock Amount of shares purchased in the open market Payments for Repurchase of Common Stock City Area Code City Area Code Scenario [Axis] Target [Axis] Target [Axis] Schedule Of Available For Sale Securities [Table] Schedule of Available-for-sale Securities [Table] Other Income Other Income Document Period End Date Document Period End Date Revenue [Policy Text Block] Revenue [Policy Text Block] Diluted (dollars per share) Earnings Per Share, Diluted Dilutive potential shares from unvested restricted shares (shares) Incremental Common Shares Attributable To Nonvested Restricted Shares Incremental common shares attributable to nonvested restricted shares. Number of operating segments Number of Reportable Segments Sales and marketing Selling and Marketing Expense Investments, Debt and Equity Securities [Abstract] Investments, Debt and Equity Securities [Abstract] Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Treasury Stock [Text Block] Treasury Stock [Text Block] Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Entity Entity [Domain] Trust Trust for Benefit of Employees [Member] Deferred income taxes Deferred Income Tax Expense (Benefit) Statistical Measurement [Domain] Statistical Measurement [Domain] Disaggregation of Revenue [Abstract] Disaggregation of Revenue [Abstract] Adjustments to reconcile net income to net cash (used in) provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Investment Owned, at Fair Value Investment Owned, at Fair Value Net Cash Provided by (Used in) Financing Activities Net Cash Provided by (Used in) Financing Activities Other Revenue Misc Services [Member] Other Revenue Misc Services [Member] Other Revenue Misc Services [Member] Unrealized gains (losses) on private investments Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Income tax expense (benefit) Income Tax Expense (Benefit) Vesting [Axis] Vesting [Axis] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Unobservable input -book value multiple - minimum Unobservable input -book value multiple - minimum Unobservable input -book value multiple - minimum Restricted Stock Award, Forfeitures Restricted Stock Award, Forfeitures Related Party Related Party [Axis] Foreign Currency Transaction Gain (Loss), before Tax Foreign Currency Transaction Gain (Loss), before Tax Long-term Investments Long-term Investments Cost Equity Securities, FV-NI, Cost Earnings per share: Earnings Per Share [Abstract] Purchases of common stock with respect to awards granted Share Based Compensation Arrangement By Share Based Payment Award Available For Grant Share based awards available for future grants. Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Deferred income taxes Deferred Income Tax Assets, Net Granted (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 Compensation and benefits payable Increase (Decrease) in Employee Related Liabilities Income (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Interactive Data Current Entity Interactive Data Current ASSETS Assets [Abstract] Gain on sale of operations Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Non-cash lease expense Non-cash lease expense Non-cash lease expense Entity Registrant Name Entity Registrant Name DESCRIPTION OF THE BUSINESS Nature of Operations [Text Block] INVESTMENTS Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Performance Shares [Member] Performance Shares [Member] Wealth Management Private Wealth [Member] Private wealth. Stock Issued During Period, Value, Restricted Stock Award, Forfeitures Stock Issued During Period, Value, Restricted Stock Award, Forfeitures Europe [Member] Europe [Member] Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] Segment Reporting [Abstract] Segment Reporting [Abstract] Westwood Funds® Westwood Funds [Member] Westwood funds. Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Intangible assets, net Finite-Lived Intangible Assets, Net Investment Income, Investment Expense Investment Income, Investment Expense Trust Trust [Member] Trust. Restricted Shares Subject to Service and Performance Conditions Restricted Shares Subject To Service And Performance Conditions [Member] Restricted shares subject to service and performance conditions. Income Statement Location Income Statement Location [Domain] Statistical Measurement [Axis] Statistical Measurement [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Realized Investment Gains (Losses) Realized Investment Gains (Losses) Revenue from Contract with Customer, Including Assessed Tax Revenue from Contract with Customer, Including Assessed Tax Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Accounts payable and accrued liabilities Accounts Payable and Accrued Liabilities, Current CanadianEmployeeServiceAward [Member] CanadianEmployeeServiceAward [Member] CanadianEmployeeServiceAward [Member] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Document Transition Report Document Transition Report Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Stock Repurchased During Period, Shares Stock Repurchased During Period, Shares Cash paid during the period for income taxes Income Taxes Paid, Net Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Tax Fund purchases of common stock Fund Purchases Of Common Stock Fund purchases of common stock. Trust Fees [Member] Trust Fee [Member] Trust Fee [Member] Purchase of treasury stock under employee stock plans (in shares) Treasury Stock, Shares, Acquired, Employee Stock Plan Treasury Stock, Shares, Acquired, Employee Stock Plan Variable Interest Entities [Abstract] Variable Interest Entities [Abstract] Variable interest entities. Impairment of Intangible Assets (Excluding Goodwill) Impairment of Intangible Assets (Excluding Goodwill) Discrete tax expense from stock-based compensation Discrete tax expense from stock-based compensation Discrete tax expense from stock-based compensation Document Quarterly Report Document Quarterly Report Common stock, shares authorized Common Stock, Shares Authorized Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Nonvested restricted shares Non-vested, beginning balance, shares Non-vested, ending balance, shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Investment Balances Debt Securities, Trading, and Equity Securities, FV-NI [Table Text Block] Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] Stock based compensation expense Share-based Payment Arrangement, Noncash Expense Operating Lease, Liability, Current Operating Lease, Liability, Current Computation of Basic and Diluted Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Entity File Number Entity File Number Accrued dividends DividendsAccrued DividendsAccrued Effect of currency rate changes on cash Effect of Exchange Rate on Cash and Cash Equivalents Compensation and benefits payable Employee-related Liabilities, Current Level 2 Fair Value, Inputs, Level 2 [Member] Income Tax Disclosure [Text Block] Income Tax Disclosure [Text Block] Payments to Acquire Intangible Assets Payments to Acquire Intangible Assets Stock Repurchased and Retired During Period, Shares Stock Repurchased and Retired During Period, Shares Dividends payable, date of record Dividends Payable, Date of Record Antidilutive Securities Antidilutive Securities [Axis] Restricted Stock Subject To Service And Performance Conditions Policy [Text Block] Restricted Stock Subject To Service And Performance Conditions Policy [Text Block] Restricted stock subject to service and performance conditions. DomesticServiceAndPerformanceAward [Member] DomesticServiceAndPerformanceAward [Member] DomesticServiceAndPerformanceAward [Member] Dividends declared Dividends, Common Stock Document Fiscal Year Focus Document Fiscal Year Focus LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] Entity Current Reporting Status Entity Current Reporting Status Other long-term assets Other Assets, Noncurrent Other Comprehensive Income (Loss), Net of Tax Other Comprehensive Income (Loss), Net of Tax Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Accounts payable and accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Restricted Stock Subject Only To A Service Condition Policy [Text Block] Restricted Stock Subject Only To A Service Condition Policy [Text Block] Restricted stock subject only to a service condition. Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Purchase of property and equipment Payments to Acquire Property, Plant, and Equipment Income Taxes Receivable, Current Income Taxes Receivable, Current Due from related party Due from Related Parties Westwood International Advisors Inc Westwood International Advisors Inc [Member] Westwood International Advisors Inc. Net change in unrealized appreciation (depreciation) on private investments Unrealized Gain (Loss) on Investments Subsequent Event [Table] Subsequent Event [Table] Remaining unrecognized compensation cost recognized over a remaining weighted average period Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Restricted Stock Subject Only to a Service Condition Restricted Stock Subject Only To Service Condition [Member] Restricted stock subject only to service condition. Loss on Contract Termination Loss on Contract Termination Accounting Policies [Abstract] Accounting Policies [Abstract] Unrealized Gain on Securities Unrealized Gain on Securities Entity Address, City or Town Entity Address, City or Town Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Revenue from Contract with Customer, Excluding Assessed Tax Revenue from Contract with Customer [Text Block] Common Trust Funds Common Trust Funds [Member] Common trust funds. Unobservable Measurement Input, Uncertainty, Description Unobservable Measurement Input, Uncertainty, Description Equity funds Equity Funds [Member] 359000 Accrued Purchases Of Treasury Stock Accrued Purchases Of Treasury Stock United States [Member] UNITED STATES Net (purchases) sales of trading securities Increase (Decrease) in Debt Securities, Trading, and Equity Securities, FV-NI Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Fiduciary and Trust [Member] Fiduciary and Trust [Member] Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax Cost Debt Securities, Trading, and Equity Securities, FV-NI, Cost Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] Entity Tax Identification Number Entity Tax Identification Number Geographical [Domain] Geographical [Domain] Income Statement Location Income Statement Location [Axis] Operating Segments Operating Segments [Member] Eliminations Intersegment Eliminations [Member] Net Cash Provided by (Used in) Investing Activities Net Cash Provided by (Used in) Investing Activities us-gaap_EquitySecuritiesMember [Member] us-gaap_EquitySecuritiesMember [Member] Exchange-traded bond funds Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Current Fiscal Year End Date Current Fiscal Year End Date General and administrative General and Administrative Expense Canadian Plan Canadian Plan [Member] Canadian Plan. Significant Accounting Policies Significant Accounting Policies [Text Block] Shares Issued, Shares, Share-based Payment Arrangement, Forfeited Shares Issued, Shares, Share-based Payment Arrangement, Forfeited Westwood mutual funds Mutual Fund Administration And Distribution Expenses related to the administration, distribution and marketing of mutual funds. Document Fiscal Period Focus Document Fiscal Period Focus Common stock, shares issued Common Stock, Shares, Issued Total expenses Costs and Expenses Common stock, par value (dollars per share) Common Stock, Par or Stated Value Per Share Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Non-vested, beginning balance, (dollars per share) Non-vested, ending balance, (dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Restricted stock returned for payment of taxes Payment, Tax Withholding, Share-based Payment Arrangement Other, net Other revenue Other revenue EARNINGS PER SHARE Earnings Per Share [Text Block] Entity Filer Category Entity Filer Category Shares remain available for issuance Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Information technology Communications and Information Technology Property and equipment, accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Equity Award Award Type [Domain] Fees earned from related party Revenue from Related Parties Employee compensation and benefits Labor and Related Expense Trust performance-based fees [Member] Trust performance-based fees [Member] Trust performance-based fees Variable Interest Entities Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract] DomesticEmployeeServiceAward [Member] DomesticEmployeeServiceAward [Member] DomesticEmployeeServiceAward [Member] Equity Securities, FV-NI, Gain (Loss) [Abstract] Equity Securities, FV-NI, Gain (Loss) [Abstract] Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease) Effective Income Tax Rate Reconciliation, Percent Effective Income Tax Rate Reconciliation, Percent Accrued liability Mutual Fund Incentive Award Liability Mutual fund incentive award liability. Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Accrued dividends Dividends Payable Non Current Dividends payable non current. Investments [Domain] Investments [Domain] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Total liabilities Liabilities Common stock, $0.01 par value, authorized 25,000,000 shares, issued 10,630,452 and outstanding 8,313,003 shares at March 31, 2021; issued 10,500,549 and outstanding 8,326,948 shares at December 31, 2020 Common Stock, Value, Issued Fair Value Inputs [Abstract] (Deprecated 2018-01-31) Fair Value Inputs [Abstract] (Deprecated 2018-01-31) Vesting [Domain] Vesting [Domain] Private Wealth Advisory [Member] Private Wealth Advisory [Member] Private Wealth [Member] Advisory Advisory [Member] Advisory. Restricted Stock, Value, Shares Issued Net of Tax Withholdings Restricted Stock, Value, Shares Issued Net of Tax Withholdings Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Gross Unrealized Gains Debt Securities, Trading, Unrealized Gain Basic (shares) Weighted average shares outstanding - basic (shares) Weighted Average Number of Shares Outstanding, Basic Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Equity Components Equity Components [Axis] Gain (Loss) on Investments Gain (Loss) on Investments Gross Unrealized Gains Debt Securities, Trading, and Equity Securities, Unrealized Gain Debt Securities, Trading, and Equity Securities, Unrealized Gain Beginning balance Ending balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Total stockholders' equity BALANCE BALANCE Stockholders' Equity Attributable to Parent Amortization of intangible assets Amortization of Intangible Assets Other liabilities Increase (Decrease) in Other Operating Liabilities Supplemental cash flow information: Supplemental Cash Flow Elements [Abstract] Local Phone Number Local Phone Number Forfeited (shares) Forfeited (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Schedule Of Related Party Transactions By Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] FAIR VALUE MEASUREMENTS Fair Value Disclosures [Text Block] Estimated Fair Value Estimated Fair Value Total assets measured at fair value Debt Securities, Trading, and Equity Securities, FV-NI Entity Address, Address Line One Entity Address, Address Line One Entity Emerging Growth Company Entity Emerging Growth Company Investment Type [Axis] Investment Type [Axis] Revenue Disaggregation by Geographic Location [Table Text Block] Revenue Disaggregation by Geographic Location [Table Text Block] [Table Text Block] for Revenue Disaggregation by Geographic Location [Table] stock repurchase program stock repurchase program stock repurchase program - authorization increase subsequent to financial statement date Treasury Stock, Value, Acquired, Cost Method Treasury Stock, Value, Acquired, Cost Method Anti-dilutive restricted shares Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Depreciation Depreciation Additional paid-in capital Additional Paid in Capital, Common Stock Payment for Repurchases of Stock for Benefit Plan Payment for Repurchases of Stock for Benefit Plan Payment for Repurchases of Stock for Benefit Plan Net Cash Provided by (Used in) Operating Activities Net Cash Provided by (Used in) Operating Activities Restricted shares subject only to a service condition: Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Equity Component Equity Component [Domain] Investment Advisory Services [Member] Investment Advisory Services [Member] Investment Advisory Services [Member] Trading Symbol Trading Symbol Investments, at fair value Short-term Investments Fees unpaid from related party Accounts Receivable, Related Parties, Current CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Stock Repurchase Program, Authorized Amount Stock Repurchase Program, Authorized Amount Gross Unrealized Losses Debt Securities, Trading, and Equity Securities, Unrealized Loss Debt Securities, Trading, and Equity Securities, Unrealized Loss U.S. Government and Government agency obligations US Treasury and Government [Member] Goodwill, Impairment Loss Goodwill, Impairment Loss Investment Performance [Member] Investment Performance [Member] Fee revenues from Westwood VIEs Variable Interest Entity, Measure of Activity, Revenues Unobservable input -book value multiple - maximum Unobservable input -book value multiple - maximum Unobservable input -book value multiple - maximum Restricted stock returned for payment of taxes, shares Restricted Stock, Shares Issued Net of Shares for Tax Withholdings Entity Shell Company Entity Shell Company Income Statement [Abstract] Income Statement [Abstract] VARIABLE INTEREST ENTITIES Variable Interest Entity Disclosure [Text Block] Proceeds from Sale of Debt and Equity Securities, FV-NI, Held-for-investment Proceeds from Sale of Debt and Equity Securities, FV-NI, Held-for-investment