Segment Reporting [Abstract] Net income Net Income (Loss) Attributable to Parent Number of operating segments Number of Reportable Segments Variable Interest Entities [Abstract] Variable interest entities. Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Divestiture of Omaha Operations [Table] Cash Proceeds From Divestiture [Table] Cash Proceeds From Divestiture [Table] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Purchase Price Allocation [Axis] Purchase Price Allocation [Axis] Purchase Price Allocation [Axis] Purchase Price Allocation [Domain] Purchase Price Allocation [Domain] [Domain] for Purchase Price Allocation [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Cash Proceeds From Divestiture [Line Items] Cash Proceeds From Divestiture [Line Items] [Line Items] for Cash Proceeds From Divestiture [Table] Proceeds from sale of operations Proceeds from Divestiture of Businesses Accounts receivable Accounts Receivable, Net, Current Other current assets Other Assets, Current Goodwill Goodwill Intangible assets, net Finite-Lived Intangible Assets, Net Property and equipment, net of accumulated depreciation of $6,055 and $5,673 Property, Plant and Equipment, Net Accounts payable and accrued liabilities Accounts Payable and Accrued Liabilities, Current Other liabilities Other Liabilities, Noncurrent Gain on sale of operations Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Disaggregation of Revenue [Abstract] Disaggregation of Revenue [Table Text Block] Disaggregation of Revenue [Table Text Block] 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] Fair Value Disclosures [Abstract] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [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] Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block] Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block] Employee Benefits and Share-based Compensation, Noncash [Abstract] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type Award Type [Axis] Equity Award Equity Award [Domain] DomesticEmployeeServiceAward [Member] DomesticEmployeeServiceAward [Member] DomesticEmployeeServiceAward [Member] Performance Shares [Member] Performance Shares [Member] DomesticServiceAndPerformanceAward [Member] DomesticServiceAndPerformanceAward [Member] DomesticServiceAndPerformanceAward [Member] CanadianEmployeeServiceAward [Member] CanadianEmployeeServiceAward [Member] CanadianEmployeeServiceAward [Member] Restricted Stock Restricted Stock [Member] Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Allocated Share-based Compensation Expense Allocated Share-based Compensation Expense Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] LONG-TERM INCENTIVE COMPENSATION Compensation and Employee Benefit Plans [Text Block] Consolidation, Variable Interest Entity, Policy [Policy Text Block] Consolidation, Variable Interest Entity, Policy [Policy Text Block] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Fair Value Hierarchy Including NAV [Axis] Fair Value Hierarchy Including NAV [Axis] Fair Value Hierarchy Including NAV [Axis] Fair Value Hierarchy Including NAV [Domain] Fair Value Hierarchy Including NAV [Domain] [Domain] for Fair Value Hierarchy Including NAV [Axis] Inputs, Net Asset Value [Member] Inputs, Net Asset Value [Member] Inputs, Net Asset Value [Member] Investments in securities: Investments, Fair Value Disclosure [Abstract] Investments in trading securities Trading Securities Fair Value, Net Asset (Liability) Fair Value, Net Asset (Liability) Subsequent Events [Abstract] Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] SUBSEQUENT EVENTS Subsequent Events [Text Block] Schedule Of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Variable Interest Entities Variable Interest Entities [Axis] Variable Interest Entity, Classification Variable Interest Entity, Classification [Domain] VIE Variable Interest Entity [Member] Variable interest entity. Common Trust Funds Common Trust Funds [Member] Common trust funds. UCITS Fund Undertaking For Collective Investment In Transferable Securities [Member] Undertaking for collective investment in transferable securities. Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Fee revenues from Westwood VIEs Variable Interest Entity, Measure of Activity, Revenues Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Goodwill [Table Text Block] Schedule of Goodwill [Table Text Block] Document And Entity Information [Abstract] Document and entity information. Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding 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. 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] Non-vested, beginning balance, shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Non-vested, ending balance, shares Non-vested, beginning 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 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 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 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 Non-vested, ending balance, (dollars per share) Investments, Debt and Equity Securities [Abstract] Schedule Of Investments [Table] Schedule of Investments [Table] Investment Type [Axis] Investment Type [Axis] Investments Investments [Domain] Money market funds Money Market Funds [Member] Equity funds Equity Funds [Member] Private Equity Funds [Member] Private Equity Funds [Member] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] U.S. Government and Government agency obligations US Treasury and Government [Member] Schedule Of Investments [Line Items] Schedule of Investments [Line Items] Cost Trading Securities, Cost Trading Securities, Unrealized Holding Gain Trading Securities, Unrealized Holding Gain Trading Securities, Unrealized Holding Loss Trading Securities, Unrealized Holding Loss Estimated Market Value DESCRIPTION OF THE BUSINESS Nature of Operations [Text Block] Date of incorporation Entity Incorporation, Date of Incorporation Disposal Groups, Including Discontinued Operations [Table Text Block] Disposal Groups, Including Discontinued Operations [Table Text Block] Restricted Stock Subject Only to a Service Condition Restricted Stock Subject Only To Service Condition [Member] Restricted stock subject only to service condition. Total Expense Recorded for Stock Based Compensation Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Status and Changes in Restricted Stock Grants that Subject to Service Condition Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] VARIABLE INTEREST ENTITIES Variable Interest Entity Disclosure [Text Block] Accounting Policies [Abstract] 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. 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. Revenue Recognition, Policy [Policy Text Block] Revenue Recognition, Policy [Policy Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] ACQUISITIONS, GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill and Intangible Assets Disclosure [Text Block] Related Party Transactions [Abstract] RELATED PARTY TRANSACTIONS Related Party Transactions Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments Operating Segments [Member] Westwood Holdings Corporate, Non-Segment [Member] Eliminations Intersegment Eliminations [Member] Segments [Axis] Segments [Axis] Segment [Domain] Segments [Domain] Trust Trust [Member] Trust. Advisory Advisory [Member] Advisory. Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] ReconciliationFromNetIncomeToNonGaapMeasure [Table Text Block] ReconciliationFromNetIncomeToNonGaapMeasure [Table Text Block] ReconciliationFromNetIncomeToNonGaapMeasure [Table Text Block] Net fee revenues from external sources Fees and Commissions Net intersegment revenues Net Intersegment Revenues Net intersegment revenues. Net interest and dividend revenue Investment Income, Net Other, net Other Revenue, Net Total revenues Revenues Net income Intangible amortization Amortization of Intangible Assets Deferred taxes on goodwill Deferred Other Tax Expense (Benefit) Economic Earnings Economic Earnings Losses Economic Earnings is a non-U.S. generally accepted accounting principles (“non-GAAP”) performance measure of segment profit or loss. We provide this measure in addition to, but not as a substitute for, net income, which is reported on a U.S. GAAP basis. Both our management and Board of Directors review Economic Earnings to evaluate our ongoing performance, allocate resources and review dividend policy. We believe that this non-GAAP performance measure of segment profit or loss, while not a substitute for GAAP net income, is useful for management and investors when evaluating our underlying operating and financial performance and our available resources. We do not advocate that investors consider this non-GAAP measure of segment profit or loss without considering financial information prepared in accordance with GAAP. Segment assets Assets Segment goodwill Investment Balances Trading Securities [Table Text Block] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer, Excluding Assessed Tax Revenue from Contract with Customer [Text Block] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Investment Advisory Services [Member] Investment Advisory Services [Member] Investment Advisory Services [Member] Mutual Fund Advisory [Member] Mutual Fund Advisory [Member] [Member] Mutual Fund Advisory [Member] [Member] Private Wealth Advisory [Member] Private Wealth Advisory [Member] Private Wealth [Member] Performance-based fees [Member] performance fee [Member] performance fee [Member] Trust Fees [Member] Trust Fee [Member] Trust Fee [Member] Other Revenue Misc Services [Member] Other Revenue Misc Services [Member] Other Revenue Misc Services [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Asia [Member] Asia [Member] Australia AUSTRALIA Canada CANADA Europe [Member] Europe [Member] United States [Member] UNITED STATES Contract with Customer, Sales Channel [Axis] Contract with Customer, Sales Channel [Axis] Contract with Customer, Sales Channel [Domain] Contract with Customer, Sales Channel [Domain] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue from Contract with Customer, Excluding Assessed Tax Revenue from Contract with Customer, Excluding Assessed Tax Loss Contingencies [Table] Loss Contingencies [Table] Litigation Case Litigation Case [Axis] Litigation Case Litigation Case [Domain] First Lawsuit by AGF First Lawsuit By A G F [Member] First lawsuit by AGF. Second Lawsuit by AGF Second Lawsuit By A G F [Member] Second lawsuit by AGF. Loss Contingency Nature Loss Contingency Nature [Axis] Loss Contingency, Nature Loss Contingency, Nature [Domain] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Other Commitment Other Commitment Lawsuit filing date Loss Contingency, Lawsuit Filing Date One-time litigation payment Litigation Settlement, Amount Awarded to Other Party Legal settlement expense Litigation Settlement, Expense Percentage of defense costs which will be covered by insurance Percentage Of Defense Costs Covered By Insurance Percentage of defense costs covered by insurance. Insurance proceeds Proceeds from Insurance Settlement, Operating Activities Receivable Loss Contingency, Receivable, Current Earnings Per Share [Abstract] Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities Antidilutive Securities [Axis] Antidilutive Securities, Name Antidilutive Securities, Name [Domain] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Anti-dilutive restricted shares Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Income Tax Disclosure [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Adoption of ASU 2016-09 [Member] Adoption of ASU 2016-09 [Member] Adoption of ASU 2016-09 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Effective Income Tax Rate Reconciliation, Percent Effective Income Tax Rate Reconciliation, Percent Provision for income taxes Income Tax Expense (Benefit) UnrecognizedTaxBenefitsIncreasesResultingFromCurrentAndPriorPeriodTaxPositions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentAndPriorPeriodTaxPositions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentAndPriorPeriodTaxPositions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Unrecognized Tax Benefits, Increase Resulting from Settlements with Taxing Authorities Unrecognized Tax Benefits, Increase Resulting from Settlements with Taxing Authorities Significant Change in Income Tax Provision is Reasonably Possible, Amount of Unrecorded Benefit Significant Change in Income Tax Provision is Reasonably Possible, Amount of Unrecorded Benefit Significant Change in Income Tax Provision is Reasonably Possible, Amount of Unrecorded Benefit Tax rate excluding ASU 2016-09 adoption Tax rate excluding ASU 2016-09 adoption Tax rate excluding ASU 2016-09 adoption Subsegments [Axis] Subsegments [Axis] Subsegments [Domain] Subsegments [Domain] Subsegments Consolidation Items [Axis] Subsegments Consolidation Items [Axis] Subsegments Consolidation Items [Domain] Subsegments Consolidation Items [Domain] Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock, Par Common Stock [Member] Additional Paid-In Capital Additional Paid-in Capital [Member] Treasury Stock Treasury Stock [Member] Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] Retained Earnings Retained Earnings [Member] Statement [Line Items] Statement [Line Items] BALANCE Stockholders' Equity Attributable to Parent BALANCE, shares Common Stock, Shares, Outstanding New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification Other comprehensive income Other Comprehensive Income (Loss), Net of Tax Issuance of restricted stock, net of forfeitures Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Issuance of restricted stock, net of forfeitures, shares Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Dividends declared Dividends, Common Stock Stock based compensation expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Reclassification of compensation liability to be paid in shares Adjustments to Additional Paid in Capital, Other Purchases of treasury stock Treasury Stock, Value, Acquired, Cost Method Treasury Shares Value Acquired for Benefit Plan Treasury Shares Value Acquired for Benefit Plan Treasury Shares Value Acquired for Benefit Plan Purchases of treasury stock, shares Treasury Stock, Shares, Acquired Restricted stock returned for payment of taxes Restricted Stock, Value, Shares Issued Net of Tax Withholdings Restricted stock returned for payment of taxes, shares Restricted Stock, Shares Issued Net of Shares for Tax Withholdings BALANCE BALANCE, shares Statement of Financial Position [Abstract] Property and equipment, accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Common stock, par value (dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Common stock, shares outstanding Treasury stock, shares Treasury Stock, Shares Dividends declared per share (dollars per share) Common Stock, Dividends, Per Share, Declared Dividends payable, date to be paid Dividends Payable, Date to be Paid Dividends payable, date of record Dividends Payable, Date of Record Stock Repurchase Program, Authorized Amount Stock Repurchase Program, Authorized Amount Computation of Basic and Diluted Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule Of Available For Sale Securities [Table] Schedule of Available-for-sale Securities [Table] Schedule Of Available For Sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Investment balances Trading Securities [Abstract] Gross Unrealized Gains Gross Unrealized Losses Schedule Of Related Party Transactions By Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party Related Party [Axis] Related Party Related Party [Domain] Trust Trust for Benefit of Employees [Member] Private Equity Investments [Member] Private Equity Investments [Member] Private Equity Investments [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Due from related party Due from Related Parties Fees earned from related party Revenue from Related Parties Fees unpaid from related party Accounts Receivable, Related Parties, Current Related Party Transaction, Purchases from Related Party Related Party Transaction, Purchases from Related Party Goodwill, Impairment Loss Goodwill, Impairment Loss Impairment of Intangible Assets (Excluding Goodwill) Impairment of Intangible Assets (Excluding Goodwill) Amortization of Intangible Assets Intangible Assets reduction from divestiture Intangible Assets reduction from divestiture Intangible Assets reduction from divestiture Goodwill reduction from divestiture Goodwill, Written off Related to Sale of Business Unit Westwood Funds® Westwood Funds [Member] Westwood funds. Westwood Hospitality Fund I LLC [Member] Westwood Hospitality Fund I LLC [Member] Westwood Hospitality Fund I LLC [Member] Private Wealth Private Wealth [Member] Private wealth. Institutional Institutional [Member] Institutional. Variable Interest Entities Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract] Assets Under Management Assets under Management, Carrying Amount Amount at Risk Risk Of Loss The risk of loss on Investment in VIE. Statement of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation Depreciation Amortization of intangible assets Unrealized (gains) losses on trading investments Trading Securities, Change in Unrealized Holding Gain (Loss) Stock based compensation expense Share-based Compensation Deferred income taxes Deferred Income Tax Expense (Benefit) Gain on sale of operations Gain on sale of operations Gain on sale of operations Other Operating Activities, Cash Flow Statement Other Operating Activities, Cash Flow Statement Change in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Net sales (purchases) of investments - trading securities Increase (Decrease) in Trading Securities Accounts receivable Increase (Decrease) in Accounts Receivable Other current assets Increase (Decrease) in Other Current Assets Accounts payable and accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Compensation and benefits payable Increase (Decrease) in Employee Related Liabilities Income taxes payable Increase (Decrease) in Accrued Taxes Payable Other liabilities Increase (Decrease) in Other Operating Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Purchase of property and equipment Payments to Acquire Property, Plant, and Equipment Payments to Acquire Investments Payments to Acquire Investments Payments to Acquire Businesses, Net of Cash Acquired Payments to Acquire Businesses, Net of Cash Acquired Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Purchases of treasury stock Payments for Repurchase of 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 Restricted stock returned for payment of taxes Payments Related to Tax Withholding for Share-based Compensation Excess tax benefits from stock based compensation Excess Tax Benefit from Share-based Compensation, Financing Activities Cash dividends paid Payments of Dividends Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations Effect of currency rate changes on cash Effect of Exchange Rate on Cash and Cash Equivalents Net Change in Cash and Cash Equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents, beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents, end of period Supplemental cash flow information: Supplemental Cash Flow Elements [Abstract] Cash paid during the period for income taxes Income Taxes Paid, Net Common stock issued for acquisition Business Combination, Consideration Transferred, Equity Interests Issued and Issuable DividendsAccrued DividendsAccrued DividendsAccrued Capital Expenditures Incurred but Not yet Paid Capital Expenditures Incurred but Not yet Paid BALANCE SHEET COMPONENTS Stockholders' Equity Note Disclosure [Text Block] Restricted Shares Subject Only to a Service Condition Forfeited (shares) INVESTMENTS Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] ASSETS Assets [Abstract] Current Assets: Assets, Current [Abstract] Cash and cash equivalents Investments, at fair value Short-term Investments Income Taxes Receivable, Current Income Taxes Receivable, Current Total current assets Assets, Current Long-term Investments Long-term Investments Deferred income taxes Deferred Tax Assets, Net, Noncurrent Total assets LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable and accrued liabilities Dividends payable Dividends Payable, Current Compensation and benefits payable Employee-related Liabilities, Current Income taxes payable Accrued Income Taxes, Current Total current liabilities Liabilities, Current Accrued dividends Dividends Payable Non Current Dividends payable non current. Accrued Income Taxes, Noncurrent Accrued Income Taxes, Noncurrent Deferred rent Deferred Rent Credit, Noncurrent Total liabilities Liabilities Commitments and contingencies Commitments and Contingencies Stockholders' Equity: Stockholders' Equity Attributable to Parent [Abstract] Common stock, $0.01 par value, authorized 25,000,000 shares, issued 10,204,887 and outstanding 9,026,806 shares at June 30, 2018; issued 9,980,827 and outstanding 8,899,587 shares at December 31, 2017 Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Treasury stock, at cost - 1,178,081 shares at June 30, 2018; 1,081,240 shares at December 31, 2017 Treasury Stock, Value Foreign currency translation adjustment Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax Retained earnings Retained Earnings (Accumulated Deficit) Total stockholders' equity Total liabilities and stockholders' equity Liabilities and Equity Earnings Per Share, Policy [Policy Text Block] Earnings Per Share, Policy [Policy Text Block] Components of accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Significant Accounting Policies [Text Block] Significant Accounting Policies [Text Block] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Share-based Compensation Award, First 50% of CEO and CIO Award Share-based Compensation Award, Tranche One [Member] Share-based Compensation Award, Second 50% of CEO and CIO Award Share-based Compensation Award, Tranche Two [Member] Share-based Compensation Award, All Other Performance Grants Share-based Compensation Award, Tranche Three [Member] Scenario [Axis] Target [Axis] Target [Axis] Target [Domain] Target [Domain] [Domain] for Target [Axis] Target [Member] Target [Member] Target [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Canadian Plan Canadian Plan [Member] Canadian Plan. Legal Entity Legal Entity [Axis] Entity Entity [Domain] Westwood International Advisors Inc Westwood International Advisors Inc [Member] Westwood International Advisors Inc. Defined Benefit Plan, Asset Categories [Axis] Defined Benefit Plan, Asset Categories [Axis] Plan Asset Categories [Domain] Plan Asset Categories [Domain] Mutual Fund [Member] Mutual Fund [Member] Share-based Compensation Arrangement by Share-based Payment Award, Shares Purchased for Award Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Share Pretax Income Goal Share Pretax Income Goal Share pretax income goal. Percentage of Pretax income Goal Earned Percentage of Pretax income Goal Earned Percentage of Pretax income Goal Earned 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 Shares remain available for issuance Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 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 Fund purchases of common stock Fund Purchases Of Common Stock Fund purchases of common stock. 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. Share price Share Price Amount of shares purchased in the open market Purchases of treasury stock, shares Remaining unrecognized compensation cost Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options Remaining unrecognized compensation cost recognized over a remaining weighted average period Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Nonvested restricted shares Mutual fund vesting period Share Based Compensation Arrangement With Individual Requisite Service Period Share based compensation arrangement with individual requisite service period. Service period of mutual fund share incentive award Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Expense related to mutual fund share incentive awards Accrued liability Mutual Fund Incentive Award Liability Mutual fund incentive award liability. FAIR VALUE MEASUREMENTS Fair Value Disclosures [Text Block] SEGMENT REPORTING Segment Reporting Disclosure [Text Block] Income Statement [Abstract] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] REVENUES: Revenues [Abstract] Advisory fees: Investment Advisory, Management and Administrative Fees [Abstract] Asset-based Investment Advisory Fees Performance-based Performance Fees Trust fees Trust Fees Total fees earned from providing trust and custody services. Other, net Investment Income And Loss Represents the total of realized and unrealized gains and losses on investments and interest and dividend income, including any amortization and accretion (as applicable) of discounts and premiums, earned from (1) investment securities; (2) federal funds; (3) dividend income; or (4) other investments not otherwise specified herein. EXPENSES: Costs and Expenses [Abstract] Employee compensation and benefits Labor and Related Expense Sales and marketing Selling and Marketing Expense Westwood mutual funds Mutual Fund Administration And Distribution Expenses related to the administration, distribution and marketing of mutual funds. Information technology Communications and Information Technology Professional services Professional Fees General and administrative General and Administrative Expense Total expenses Costs and Expenses Operating Income (Loss) Operating Income (Loss) Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Total comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Earnings per share: Basic (dollars per share) Earnings Per Share, Basic Diluted (dollars per share) Earnings Per Share, Diluted Weighted average shares outstanding: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Basic (shares) Weighted Average Number of Shares Outstanding, Basic Diluted (shares) Weighted Average Number of Shares Outstanding, Diluted Cash dividends declared per share (dollars per share) Components of Accumulated Other Comprehensive Loss Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Computation of Basic and Diluted Shares Earnings Per Share Reconciliation [Abstract] Weighted average shares outstanding - basic (shares) Dilutive potential shares from unvested restricted shares (shares) Incremental Common Shares Attributable To Nonvested Restricted Shares Incremental common shares attributable to nonvested restricted shares. Incremental Common Shares Attributable to Dilutive Effect of Contingently Issuable Shares Incremental Common Shares Attributable to Dilutive Effect of Contingently Issuable Shares Weighted average shares outstanding - diluted (shares) Earnings per share: Earnings Per Share, Basic and Diluted [Abstract] EARNINGS PER SHARE Earnings Per Share [Text Block] Income Tax Disclosure [Text Block] Income Tax Disclosure [Text Block]