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Number of operating segments Number of Reportable Segments Sales and marketing Selling and Marketing Expense Trading Symbol Trading Symbol 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 Legal Entity Legal Entity [Axis] 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 (loss) 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] Entity Entity [Domain] Unrealized 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 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 City Area Code City Area Code Restricted Stock Award, Forfeitures Restricted Stock Award, Forfeitures Title of 12(b) Security Title of 12(b) Security 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 (loss) 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. 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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. 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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. 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Restricted stock returned for payment of taxes 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] 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 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 Purchases of treasury stock Treasury Stock, Value, Acquired, Cost Method Security Exchange Name Security Exchange Name 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] Document Transition Report Document Transition Report Investment Advisory Services [Member] Investment Advisory Services [Member] Investment Advisory Services [Member] 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 Income Statement [Abstract] Income Statement [Abstract] VARIABLE INTEREST ENTITIES Variable Interest Entity Disclosure [Text Block]