Disclosure of Compensation Related Costs, Share-based Payments [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 [Axis] Award Type [Axis] Award Type [Domain] Equity Award [Domain] Stock Options Employee Stock Option [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Share-based Compensation Arrangement by Share-based Payment Award Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Fair value of stock options granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value Vesting period of options Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Expiration period of options Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Total intrinsic value of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Cash received for options exercised Proceeds from Stock Options Exercised Intrinsic value of exercisable options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Options available for future grant under the Company's option plans (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Weighted average fair value of options granted (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Debt Disclosure [Abstract] Schedule of Principal Terms of Senior Notes Outstanding Schedule of Maturities of Long-term Debt [Table Text Block] Accounting Policies [Abstract] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Principles of Consolidation Consolidation, Policy [Policy Text Block] Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Receivables Receivables, Policy [Policy Text Block] Investments in Marketable Securities Marketable Securities, Policy [Policy Text Block] Fair Value Measurements Fair Value Measurement, Policy [Policy Text Block] Acquired Client Relationships and Goodwill Goodwill and Intangible Assets, Policy [Policy Text Block] Fixed Assets Property, Plant and Equipment, Policy [Policy Text Block] Leases Lessee, Leases [Policy Text Block] Issuance Costs Debt, Policy [Policy Text Block] Derivative Financial Instruments Derivatives, Policy [Policy Text Block] Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Contingent Payment Arrangements Business Combinations Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Foreign Currency Translation Foreign Currency Transactions and Translations Policy [Policy Text Block] Concentration of Credit Risk Concentration Risk, Credit Risk, Policy [Policy Text Block] Earnings Per Share Earnings Per Share, Policy [Policy Text Block] Share-Based Compensation Plans Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Recent Accounting Developments New Accounting Pronouncements, Policy [Policy Text Block] Fixed Assets and Lease Commitments [Abstract] Fixed Assets and Lease Commitments [Abstract] Schedule of Fixed Assets Property, Plant and Equipment [Table Text Block] Schedule of Aggregate Future Minimum Payments for Operating Leases Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Marketable Securities [Abstract] Cost Marketable Securities, Cost Marketable Securities, Cost Unrealized gains Marketable Securities, Unrealized Gains Marketable Securities, Unrealized Gains Unrealized losses Marketable Securities, Unrealized Losses Marketable Securities, Unrealized Losses Fair value Marketable Securities Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Deferred Tax Assets Deferred Tax Assets, Net [Abstract] Deferred compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits State net operating loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards, State and Local Foreign loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards, Foreign Tax benefit of uncertain tax positions Deferred Tax Assets, Tax Benefit on Uncertain Tax Positions Represents the tax benefit as of the balance sheet date of the amount of future tax deductions arising from uncertain tax positions. Deferred income Deferred Tax Assets, Deferred Income Accrued expenses Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Other Deferred Tax Assets, Other Total deferred tax assets Deferred Tax Assets, Gross Valuation allowance Deferred Tax Assets, Valuation Allowance Deferred tax assets, net of valuation allowance Deferred Tax Assets, Net of Valuation Allowance Deferred Tax Liabilities Deferred Tax Liabilities, Gross [Abstract] Intangible asset amortization Deferred Tax Liabilities, Intangible Assets Convertible securities interest Deferred Tax Liabilities, Convertible Securities Interest The cumulative amount of the estimated future tax effects attributable to the difference between the tax basis of convertible securities interest and the basis of convertible securities interest computed in accordance with generally accepted accounting principles. Non-deductible intangible amortization Deferred Tax Liabilities, Nondeductible Intangible Assets, Amortization Represents the tax effect of future book amortization of intangibles that do not qualify for step-up and amortization for tax purposes. Deferred income Deferred Tax Liabilities, Tax Deferred Income Other Deferred Tax Liabilities, Other Total deferred tax liabilities Deferred Tax Liabilities, Gross Deferred income tax liability (net) Deferred Income Tax Liabilities, Net Affiliate Equity [Abstract] Affiliate Equity [Abstract] Affiliate Equity [Table] Affiliate Equity [Table] Affiliate Equity [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Controlling Interest Affiliated Entity [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Non- controlling Interests Noncontrolling Interest [Member] Affiliate Equity Expense Affiliate Equity [Line Items] [Line Items] for Affiliate Equity [Table] Controlling interest Compensation Expenses Related to Affiliate Equity Represents the compensation expenses related to Affiliate equity. Non-controlling interests Affiliate Equity Compensation Expense, Attributable to Noncontrolling Interest Affiliate Equity Compensation Expense, Attributable to Noncontrolling Interest Total Affiliate Equity Compensation Expense, Including Portion Attributable to Noncontrolling Interest Affiliate Equity Compensation Expense, Including Portion Attributable to Noncontrolling Interest Unrecognized Affiliate Equity Expense Unrecognized Affiliate Equity Expense [Abstract] Unrecognized Affiliate Equity Expense [Abstract] Controlling Interest Unrecognized Compensation Expenses Related to Affiliate Equity Attributable to Controlling Interest Unrecognized Compensation Expenses Related to Affiliate Equity Attributable to Controlling Interest Remaining Life Affiliate Equity, Unrecognized Compensation Expense, Weighted Average Period of Recognition Affiliate Equity, Unrecognized Compensation Expense, Weighted Average Period of Recognition Non-controlling Interests Affiliate Equity Unrecognized Compensation Expense, Attributable to Noncontrolling Interest Affiliate Equity Unrecognized Compensation Expense, Attributable to Noncontrolling Interest Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Acquired Client Relationships (Net) Customer Relationships [Member] Goodwill Goodwill [Line Items] Goodwill impairment Goodwill, Impairment Loss Intangible amortization expense Amortization of Intangible Assets Intangible future amortization expense in 2019 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Intangible future amortization expense in 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Two Intangible future amortization expense in 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Three Intangible future amortization expense in 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Four Intangible future amortization expense in 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Five Definite-lived and indefinite-lived intangibles impairments Asset Impairment Charges Statement of Financial Position [Abstract] Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Treasury stock, shares (in shares) Treasury Stock, Shares Equity Method Investments and Joint Ventures [Abstract] Equity Investments in Affiliates Equity Method Investments and Joint Ventures Disclosure [Text Block] Forward Equity Sale Agreements -- None. No documentation exists for this element. -- Equity Distribution Program Forward Equity Sale Agreements [Text Block] Information about forward equity sale agreements, which may include amounts outstanding and capacity to sell. Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Commitments and Contingencies Disclosure [Abstract] Commitment and Contingencies [Table] Commitment and Contingencies [Table] Represents commitments and contingencies of the entity. Consolidated Affiliates Consolidated Entities [Member] Equity Method Investee Equity Method Investee [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Non-US Non-US [Member] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Scenario, Forecast Scenario, Forecast [Member] Commitments and Contingencies Commitment and Contingencies [Line Items] -- None. No documentation exists for this element. -- Co-investment commitments in partnership Investment Commitment, Amount The amount that the entity agreed to co-invest in certain investment partnerships where the entity serves as the general partner. Other commitments Other Commitment Other commitment, expected payments Other Commitment Expected Payments Other Commitment Expected Payments Other commitments, present value of expected payments Other Commitment Present Value of Expected Payments Other Commitment Present Value of Expected Payments Ownership percentage held by minority interest in affiliated to the Company Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Noncontrolling interest, sale of ownership percentage Noncontrolling Interest, Notification of Possible Sale of Noncontrolling Interest, Percentage Noncontrolling Interest, Notification of Possible Sale of Noncontrolling Interest, Percentage Statement of Cash Flows [Abstract] Cash flow from (used in) operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Adjustments to reconcile Net income to net cash flow from operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Intangible amortization and impairments Amortization and Impairments of Intangible Assets Amortization and Impairments of Intangible Assets Depreciation and other amortization Depreciation and Other Amortization The aggregate expense charged against earnings to allocate the cost of tangible assets to periods in which the assets are used and held and to allocate the cost of issuing debt to periods in which the debt is outstanding. As a noncash expense, this element is added back to net income when calculating cash provided by (used in) operations using the indirect method. Deferred income tax provision Deferred Income Tax Expense (Benefit) Equity method (income) loss (net) Income (Loss) from Equity Method Investments Distributions of earnings received from equity method investments Proceeds from Equity Method Investment, Distribution Share-based compensation and Affiliate equity expense Share-based Compensation and Affiliate Equity Expense Share-based Compensation and Affiliate Equity Expense Other non-cash items Other Noncash Income (Expense) Changes in assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Purchases of securities by Affiliate sponsored consolidated products Purchases of Securities by Affiliate Sponsored Consolidated Products Purchases of Securities by Affiliate Sponsored Consolidated Products Sales of securities by Affiliate sponsored consolidated products Sale of Securities by Affiliate Sponsored Consolidated Products Sale of Securities by Affiliate Sponsored Consolidated Products (Increase) decrease in receivables Increase (Decrease) in Receivables Increase in other assets Increase (Decrease) in Other Operating Assets Increase (decrease) in payables, accrued liabilities and other liabilities Increase (Decrease) in Operating Liabilities Cash flow from operating activities Net Cash Provided by (Used in) Operating Activities Cash flow from (used in) investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Investments in Affiliates Payments to Acquire Interest in Subsidiaries and Affiliates Purchase of fixed assets Payments to Acquire Property, Plant, and Equipment Purchase of investment securities Payments to Acquire Marketable Securities Sale of investment securities Payments for (Proceeds from) Investments Cash flow from (used in) investing activities Net Cash Provided by (Used in) Investing Activities Cash flow from (used in) financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Borrowings of senior bank debt and senior notes Proceeds from Issuance of Long-term Debt Repayments of senior bank debt and senior notes Repayments of Long-term Debt Repurchase of common stock Payments for Repurchase of Common Stock Issuance of common stock Proceeds from Issuance of Common Stock Dividends paid on common stock Payments of Ordinary Dividends, Common Stock Distributions to non-controlling interests Payments of Ordinary Dividends, Noncontrolling Interest Affiliate equity issuances and repurchases Proceeds from (Payments for) Affiliate Equity Issuances and Repurchases The net cash inflow (outflow) resulting from the affiliate share transaction. Subscriptions to Affiliate sponsored consolidated products, net of redemptions Subscriptions to Affiliate Sponsored Consolidated Products, Net of Redemptions Subscriptions to Affiliate Sponsored Consolidated Products, Net of Redemptions Other financing items Proceeds from (Payments for) Other Financing Activities Cash flow from (used in) financing activities Net Cash Provided by (Used in) Financing Activities Effect of foreign currency exchange rate changes on cash and cash equivalents Effect of Exchange Rate on Cash and Cash Equivalents Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Net cash outflows upon the consolidation and deconsolidation of Affiliate sponsored products Cash Divested from Deconsolidation Cash and cash equivalents at end of period Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Interest paid Interest Paid, Excluding Capitalized Interest, Operating Activities Income taxes paid Income Taxes Paid, Net Supplemental disclosure of non-cash financing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Payables recorded for Affiliate equity repurchases Payables Recorded for Affiliate Equity Purchases Payables recorded for affiliate equity purchases. Payables recorded for share repurchases Payables Recorded, But Not Yet Paid, Share Repurchases Payables Recorded, But Not Yet Paid, Share Repurchases Stock issued upon vesting of restricted stock units Stock Issued Under Other Incentive Plans Stock Issued Under Other Incentive Plans Stock received for tax withholdings on share-based payments Shares Received for Tax Withholding for Share Based Compensation, Value Shares Received for Tax Withholding for Share Based Compensation, Value Stock received for the exercise of stock options Shares Received From Stock Options Exercised, Value Shares Received From Stock Options Exercised, Value Share-Based Compensation Expense Allocated Share-based Compensation Expense Tax Benefit Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative [Table] Derivative [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Derivatives in Net Investment Hedging Relationship Net Investment Hedging [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Forward contracts Foreign Exchange Forward [Member] Put options Put Option [Member] Call options Call Option [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Interest Expense Interest Expense [Member] Derivative [Line Items] Derivative [Line Items] Gain (Loss) Recognized in Other Comprehensive Income Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), Net of Tax Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), Net of Tax Gain (Loss) Recognized in Earnings from Excluded Components Gain (Loss) on Derivative Used in Net Investment Hedge, after Tax Variable Interest Entities -- None. No documentation exists for this element. -- Investments in Affiliates and Affiliate Sponsored Investment Products Variable Interest Entities Disclosure [Text Block] This element represents the disclosure of variable interest entities (VIE), including, but not limited to the nature, purpose, size, and activities of the VIE, the carrying amount and classification of consolidated assets that are collateral for the VIE's obligations, lack of recourse if creditors (or beneficial interest holders) of a consolidated VIE have no recourse to the general credit of the primary beneficiary. Which also include information related to Sponsored Investment Funds and Trust Preferred Vehicles related to variable interest entities (VIE). Investments in Marketable Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Goodwill and Acquired Client Relationships Goodwill and Intangible Assets Disclosure [Text Block] Noncontrolling Interest [Abstract] Noncontrolling Interest [Table] Noncontrolling Interest [Table] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Affiliate sponsored investment products Sponsored Investment Funds [Member] Represents investment funds in to which the entity is not the primary beneficiary of these VIEs. Noncontrolling Interest [Line Items] Noncontrolling Interest [Line Items] Term of conditional right put interest Term Of Conditional Right to Put Interest Term Of Conditional Right to Put Interest Redeemable Non-controlling Interests Redeemable Noncontrolling Interest [Roll Forward] -- None. No documentation exists for this element. -- Balance, beginning of period Redeemable Noncontrolling Interest, Equity, Carrying Amount Changes attributable to Affiliate sponsored consolidated products Redeemable Noncontrolling Interest Change in Redemption Value Increase (decrease) in redeemable non-controlling interests during the period as a result of a change in the redemption value. Transfers to Other liabilities Noncontrolling Interest, Decrease from Transfers to Other Liabilities Noncontrolling Interest, Decrease from Transfers to Other Liabilities Transfers from Non-controlling interests Payments for Repurchase of Redeemable Noncontrolling Interest Changes in redemption value Noncontrolling Interest, Decrease from Redemptions Noncontrolling Interest, Decrease from Redemptions Balance, end of period Payables and Accruals [Abstract] Schedule of Accounts Payable and Accrued Liabilities Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Forward Contract Indexed to Issuer's Equity, Type [Axis] Forward Contract Indexed to Issuer's Equity, Type [Axis] Forward Contract Indexed to Issuer's Equity, Type [Domain] Forward Contract Indexed to Issuer's Equity, Type [Domain] Equity Distribution Program Forward Equity Agreement [Member] Forward Equity Agreement Class of Stock [Line Items] Class of Stock [Line Items] Stock program, maximum amount authorized Stock Issuable, Value, Maximum Stock Issuable, Value, Maximum Proceeds from issuance of common stock Variable Interest Entity [Abstract] Variable Interest Entity [Abstract] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Affiliates accounted for under the equity method Variable Interest Entities Previously Accounted for Under the Equity Method [Member] Variable Interest Entities Previously Accounted for Under the Equity Method Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Unconsolidated VIE Net Assets Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net Carrying Value and Maximum Exposure to Loss Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure Equity method investments in Affiliates (net) Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Carrying amount and maximum exposure to loss of equity method affiliates Equity Method Investments Net income (controlling interest) Net Income (Loss) Attributable to Parent Increase (decrease) in controlling interest paid-in capital from Affiliate equity issuances Adjustments to Additional Paid in Capital Increase in Carrying Amount of Redeemable Noncontrolling Interests Adjustments to Additional Paid in Capital Increase in Carrying Amount of Redeemable Noncontrolling Interests Decrease in controlling interest paid-in capital from Affiliate equity repurchases Adjustments to Additional Paid in Capital Decrease in Carrying Amount of Redeemable Noncontrolling Interests Adjustments to Additional Paid in Capital Decrease in Carrying Amount of Redeemable Noncontrolling Interests Net income (controlling interest) including the net impact of Affiliate equity transactions Increase (Decrease) in Equity Due to Profit (Loss) and Net Transfers with Noncontrolling Interests Increase (decrease) in equity during the period due to net income attributable to the parent company and net transfers with non-controlling interests. Assumptions used to determine fair value of options granted Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Expected volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Expected life of options (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Forfeiture rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions Forfeiture Rate Represents the expected rate the entity will cancel the stock option awards due to nonfulfillment of certain conditions of equity-based compensation arrangements. Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Unsecured Debt Unsecured Debt [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Revolver Senior Unsecured Credit Facility Revolver [Member] Senior Unsecured Credit Facility Revolver Term Loan Senior Unsecured Term Loan [Member] Senior Unsecured Term Loan Debt Instrument Debt Instrument [Line Items] Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Maximum borrowing capacity, additional amount Line of Credit Facility, Maximum Borrowing Capacity, Additional Amount Line of Credit Facility, Maximum Borrowing Capacity, Additional Amount Outstanding borrowings Long-term Line of Credit Weighted average interest rate Debt, Weighted Average Interest Rate Term loan outstanding Long-term Debt Weighted average interest rate on amount outstanding Long-term Debt, Weighted Average Interest Rate, at Point in Time Commitment fee amount Line of Credit Facility, Commitment Fee Amount Stockholders' Equity Note [Abstract] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Foreign Currency Translation Adjustment Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member] Realized and Unrealized Gains (Losses) on Derivative Financial Instruments Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] Change in net unrealized gain (loss) on investment securities Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member] Noncontrolling Interest Accumulated Net Investment Gain (Loss) Attributable to Noncontrolling Interest [Member] Total AOCI Including Portion Attributable to Noncontrolling Interest [Member] Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Beginning Balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Other comprehensive income (loss) before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Amounts reclassified Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Ending Balance Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Fair Value Measured at Net Asset Value Per Share [Member] Fair Value Measured at Net Asset Value Per Share [Member] Investment Type [Axis] Investment Type [Axis] Investment Type Categorization [Domain] Investments [Domain] Private equity Private Equity Funds [Member] Other funds Other Funds [Member] Investments held in other funds. Other investments Other than Securities Investment [Member] Controlling interests Parent [Member] NAV of investments at fair value Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] Alternative Investment Alternative Investment Unfunded Commitments Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments Life of funds (in years) Fair Value, Investments, Entities That Calculate NAVs, Life of Fund Fair Value, Investments, Entities That Calculate NAVs, Life of Fund Restricted Stock Restricted Stock [Member] Restricted Stock Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Unvested units - December 31, 2017 (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Units granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Units vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Units forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Unvested units - December 31, 2018 (in shares) Weighted Average Grant Date Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Unvested units - December 31, 2017 (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Units granted (in usd 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 Units vested (in usd 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 Units forfeited (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Unvested units - December 31, 2018 (in usd per share) Quarterly Financial Information Disclosure [Abstract] Selected Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Equipment Office Equipment [Member] Computer software Software and Software Development Costs [Member] Buildings Building [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] ASU 2016-02 Accounting Standards Update 2016-02 [Member] Fixed Assets Property, Plant and Equipment [Line Items] Number of operating segments Number of Operating Segments Estimated useful lives of office equipment, furniture and fixtures Property, Plant and Equipment, Useful Life Lease liability Operating Lease, Liability Right-of-use asset Operating Lease, Right-of-Use Asset Income Tax Provision [Table] Income Tax Provision [Table] Schedule reflecting information of income tax attributable to controlling and noncontrolling interests. Non-Controlling Interests Income tax provision Income Tax [Line Items] -- None. No documentation exists for this element. -- Current tax Current Income Tax Expense (Benefit) Intangible-related deferred taxes Deferred Income Tax Expense Related to Intangibles The component of income tax expense for the period representing the tax effect of the difference between amortization of intangibles for book purposes and amortization of intangibles for tax purposes. Other deferred taxes Deferred Other Tax Expense (Benefit) Deferred taxes Income tax expense Income Tax Expense (Benefit) Income before income taxes (controlling interest) Income (Loss) from Continuing Operations before Income Taxes Attributable to Parent This element represents the income or loss from continuing operations, before income taxes, which is attributable to the controlling interest. Effective tax rate (controlling interest) Income Tax Expense from Controlling Interest to Pretax, Income from Continued Operations Attributable to Controlling Interest Ratio A ratio calculated by dividing the amount of income tax expense attributable to the controlling interest by pretax income from continuing operations attributable to the controlling interest. Reconciliation of beginning and ending amount of unrecognized tax benefits Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Balance, beginning of period Unrecognized Tax Benefits Additions based on current year tax positions Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Additions based on prior years’ tax positions Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Reduction for prior years’ tax positions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Reductions related to lapses of statutes of limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Settlements Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities Additions (reductions) related to foreign exchange rates Unrecognized Tax Benefits, Increase (Decrease) Related to Foreign Exchange Rates The gross amount of additions (reductions) related to foreign exchange rates resulting from settlements with taxing authorities. Balance, end of period Fair value of restricted stocks granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Vesting period of restricted stocks Restricted stocks available for future grant under the Company's option plans (in shares) Schedule of Carrying Value of Convertible Securities Schedule of Convertible Securities [Table Text Block] Tabular disclosure of the carrying amount and fair value of convertible securities. Income Statement [Abstract] Consolidated revenue Revenue from Contract with Customer, Excluding Assessed Tax Consolidated expenses: Operating Expenses [Abstract] Compensation and related expenses Labor and Related Expense Selling, general and administrative Selling, General and Administrative Expense Interest expense Interest Expense Other expenses (net) Other Cost and Expense, Operating Total consolidated expenses Operating Expenses Equity method income (loss) (net) Investment and other income Investment and Other Income (Loss) The amount of income from cost method investments, foreign currency transaction gain or loss and other income recognized during the period. Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax expense Net income Net income (non-controlling interests) Noncontrolling Interest in Net Income (Loss) Other Noncontrolling Interests, Redeemable Net income (controlling interest) Average shares outstanding (basic) (in shares) Weighted Average Number of Shares Outstanding, Basic Average shares outstanding (diluted) (in shares) Weighted Average Number of Shares Outstanding, Diluted Earnings per share (basic) (in dollars per share) Earnings Per Share, Basic Earnings per share (diluted) (in dollars per share) Earnings Per Share, Diluted SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract] Schedule II Valuation and Qualifying Accounts SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Senior Notes Long-term Debt [Text Block] Equity [Abstract] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Voting Common Stock Common Class A [Member] Common Class B Common Class B [Member] Common Stock Common Stock [Member] Preferred Stock Preferred Stock [Member] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] January 2018 Program January 2018 Plan [Member] January 2018 Plan January 2017 Program January 2017 Plan [Member] January 2017 Plan Forward Equity Agreement Stock repurchase program, number of shares authorized (in shares) Stock Repurchase Program, Number of Shares Authorized to be Repurchased Shares repurchased (in shares) Treasury Stock, Shares, Acquired Average price of stock repurchased (in dollars per share) Treasury Stock Acquired, Average Cost Per Share Stock repurchase plan, number of remaining shares to be repurchased (in shares) Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased Maximum number of shares available for sale under agreement (in shares) Forward Contract Indexed to Issuer's Equity, Shares Average share price on forward basis (in dollars per share) Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share Number of shares issued to settle portion of forward equity sale (in shares) Forward Contract Indexed to Issuer's Equity, Indexed Shares Number of shares issued to settle portion of forward equity sale in cash (in shares) Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Shares, at Fair Value Average share price of shares settled in cash (in dollars per share) Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Average Price Per Share Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Average Price Per Share Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Acquired Client Relationships Under Equity Method Investments Acquired Client Relationships of Equity Method Investments [Member] Represent the description related to acquired client relationships of the entity's equity method investments. Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Investment One Sole Significant Equity Method Affiliate [Member] Sole Significant Equity Method Affiliate Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Fair value assumptions, average projected growth rate Fair Value Assumptions, Average Projected Growth Rate Fair Value Assumptions, Average Projected Growth Rate Fair value assumptions, discount rate for asset based fees Fair Value Assumptions, Discount Rate For Assets Based Fees Fair Value Assumptions, Discount Rate For Assets Based Fees Fair value assumptions, discount rate for performance based fees Fair Value Assumptions, Discount Rate For Performance Fees Fair Value Assumptions, Discount Rate For Performance Fees Fair value assumptions, market participant tax rate Fair Value Assumptions, Market Participant Tax Rate Fair Value Assumptions, Market Participant Tax Rate Impairment of equity method investment Equity Method Investment, Other than Temporary Impairment Equity method and cost method impairments Equity Method and Cost-method Investments, Other than Temporary Impairment Equity Method and Cost-method Investments, Other than Temporary Impairment Undistributed earnings from equity method affiliates Retained Earnings, Undistributed Earnings from Equity Method Investees Revenue of equity method investment affiliate investment Equity Method Investment, Summarized Financial Information, Revenue Net income of equity method affiliate investment Equity Method Investment, Summarized Financial Information, Net Income (Loss) Earnings Per Share [Abstract] Earnings Per Share Earnings Per Share [Text Block] Schedule of Tax Effects Allocated to each Component of Other Comprehensive Income Comprehensive Income (Loss) [Table Text Block] Schedule of Components of Accumulated Other Comprehensive Income, Net of Taxes Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Domestic Income (Loss) from Continuing Operations before Income Taxes, Domestic International Income (Loss) from Continuing Operations before Income Taxes, Foreign Total Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] United States UNITED STATES United Kingdom UNITED KINGDOM Other OTHER [Member] OTHER Segment Reporting Information Segment Reporting Information [Line Items] Fixed Assets (net) Property, Plant and Equipment, Net Senior Notes Senior Notes [Member] 2024 Senior Notes Senior Notes Four Point Two Five Percent Due 2024 [Member] [Member] Senior Notes Four Point Two Five Percent Due 2024 [Member] 2025 Senior Notes Senior Notes Three Point Five Zero Percent Due 2025 [Member] Senior Notes 3.50% Due 2025 Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Treasury Rate Treasury Rate [Member] Treasury Rate Debt Instrument Par value (in millions) Debt Instrument, Face Amount Stated coupon Debt Instrument, Interest Rate, Stated Percentage Redemption price percentage Debt Instrument, Redemption Price, Percentage Applicable basis spread over redemption price percentage Debt Instrument, Make Whole Premium, Discount Rate, Basis Spread on Variable Rate Debt Instrument, Make Whole Premium, Discount Rate, Basis Spread on Variable Rate Schedule of Changes in Redeemable Non-Controlling Interests Redeemable Noncontrolling Interest [Table Text Block] Related Party Transactions [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Retirement Benefits [Abstract] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Discretionary contributions to benefit plans Defined Contribution Plan, Employer Discretionary Contribution Amount Stock Options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Unexercised options outstanding - December 31, 2017 (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Options granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures Options exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Options forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Unexercised options outstanding - December 31, 2018 (in shares) Exercisable at December 31, 2018 (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Unexercised options outstanding - December 31, 2017 (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Options granted (in usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Options exercised (in usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Options forfeited (in usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Unexercised stock options outstanding - December 31, 2018 (in usd per share) Exercisable stock options at December 31, 2018 (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted Average Remaining Contractual Life (years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Stock options outstanding at December 31, 2018 (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Exercisable stock options at December 31, 2018 (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Carrying Value and Maximum Exposure to Loss Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Share-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Redeemable Non-Controlling Interests Noncontrolling Interest Disclosure [Text Block] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] Income Tax Valuation Allowance SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] Other Allowances SEC Schedule, 12-09, Allowance, Notes Receivable [Member] Valuation and Qualifying Accounts SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] Reconciliation of beginning and ending balances of valuation and qualifying accounts SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] Balance Beginning of Period SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount Additions Charged to Costs and Expenses SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Cost and Expense Additions Charged to Other Accounts SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Other Account Deductions SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction Balance End of Period Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Level 3 Fair Value, Inputs, Level 3 [Member] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Contingent payment arrangements Contingent Payment Arrangements [Member] Represents contingent payment arrangements of the entity. Affiliate equity repurchase obligations Obligations to Related Parties [Member] Represents the obligations of the entity towards related parties. Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Discounted cash flow Discounted Cash-Flow Valuation Technique [Member] Represents the discounted cash flow technique used to measure fair value. Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Growth rates Measurement Input, Long-term Revenue Growth Rate [Member] Discount rates Measurement Input, Discount Rate [Member] Weighted Average Weighted Average [Member] Quantitative information for Level 3 Fair Value Measurements Liabilities Fair Value Measurement Inputs and Valuation Techniques [Line Items] Fair value liabilities Financial and Nonfinancial Liabilities, Fair Value Disclosure Contingent payment arrangement, measurement input Contingent Payment Arrangement, Measurement Input Contingent Payment Arrangement, Measurement Input Obligations to related parties, measurement input Obligations to Related Parties, Measurement Input Obligations to Related Parties, Measurement Input Convertible Securities Convertible Securities [Text Block] Information about convertible debt arrangements, which may include amounts of borrowings, the underlying arrangements, repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, and other matters important to users of the financial statements. Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Prior Owner Prior Owner [Member] Prior Owner of entity Affiliated Entity Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Liabilities Other Liabilities [Member] Related Party Transactions Related Party Transaction [Line Items] Investment partnerships with prior owners Investment Partnerships with Prior Owners Investment Partnerships with Prior Owners Contingent liabilities arrangements to related parties Business Combination, Contingent Consideration, Liability Payments associated with contingent liabilities arrangements to related parties Payment for Contingent Consideration Liability, Operating Activities Imputed interest expenses of contingent payment arrangements Imputed Interest Expense (Income) And Contingent Payment Arrangements Imputed Interest Expense (Income) And Contingent Payment Arrangements Current: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) State Current State and Local Tax Expense (Benefit) Foreign Current Foreign Tax Expense (Benefit) Total current Deferred: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) State Deferred State and Local Income Tax Expense (Benefit) Foreign Deferred Foreign Income Tax Expense (Benefit) Total deferred Statement of Stockholders' Equity [Abstract] Dividends paid (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Schedule of Revenue and Fixed Assets, net of the Company by Geographic Location Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block] Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] State and Local Jurisdiction State and Local Jurisdiction [Member] Foreign Tax Authority Foreign Tax Authority [Member] Tax Period [Axis] Tax Period [Axis] Tax Period [Domain] Tax Period [Domain] Expire over a 20-year period Expire Over Twenty Year Period [Member] Expire Over Twenty Year Period Valuation Allowance by Deferred Tax Asset [Axis] Valuation Allowance by Deferred Tax Asset [Axis] Deferred Tax Asset [Domain] Deferred Tax Asset [Domain] Valuation Allowance, Operating Loss Carryforwards SEC Schedule, 12-09, Valuation Allowance, Operating Loss Carryforward [Member] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Provisional one-time net benefit from changes in U.S. tax laws Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit) Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit) Net income tax benefit resulting from re-measurement of Company's deferred tax assets and liabilities Tax Cuts and Jobs Act of 2017, Change in Tax Rate, Income Tax Expense (Benefit) Tax Cuts and Jobs Act of 2017, Change in Tax Rate, Income Tax Expense (Benefit) Transition tax deemed on repatriated foreign earnings and profits Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings Provisional Income Tax (Expense) Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings Provisional Income Tax (Expense) Expense recorded to reduce the carrying value of equity method affiliate Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Amount Income tax benefit related to equity method investment fair value adjustment Operating loss carryforwards Operating Loss Carryforwards State net operating loss carryforwards, expiration period Operating Loss Carryforwards, State and Local Expiration Period The period (in years) over which the state net operating loss carryforwards included in total operating loss carryforwards shall expire. Foreign operating loss carryforwards, expiration period Operating Loss Carryforwards, Foreign, Expiration Period Operating Loss Carryforwards, Foreign, Expiration Period Operating loss carryforwards, valuation allowance Increase in valuation allowance on deferred tax assets Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Amount of temporary difference due to repatriation of earnings from sale or liquidation of subsidiary Undistributed Earnings of Foreign Subsidiaries Unrecognized tax benefits that, if recognized, would affect effective tax rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Accrued income tax interest and related charges Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Net Investment Hedging Collar contracts Foreign Exchange Option [Member] Forward contract expiring 2024 Foreign Exchange Forward Expiring 2024 [Member] Foreign Exchange Forward Expiring 2024 Forward contract expiring 2021 Foreign Exchange Forward Expiring 2021 [Member] Foreign Exchange Forward Expiring 2021 Collar contract-call option Collar contract-put option Derivative, number of contracts Derivative, Number of Instruments Held Derivative, notional amount Derivative, Notional Amount Derivative, option strike price (in dollars per unit) Derivative, Foreign Currency Option Strike Price Cash collateral held from counterparty Derivative, Collateral, Obligation to Return Cash Cash collateral held at counterparty Derivative, Collateral, Right to Reclaim Cash Number of contracts with a contingent feature in a net liability position Derivative, Net Liability Position, Number of Instruments Derivative, Net Liability Position, Number of Instruments Accrued compensation Employee-related Liabilities Accrued income taxes Accrued Income Taxes Other Other Accrued Liabilities Payables and accrued liabilities Accounts Payable and Accrued Liabilities Fair Value, Assets and Liabilities, Measured on Recurring Basis Unobservable Input Reconciliation [Table] Fair Value, Assets and Liabilities, Measured on Recurring Basis Unobservable Input Reconciliation [Table] Summarization of the information required and determined to be provided for purposes of reconciling beginning and ending balances of fair value measurements of assets and liabilities using significant unobservable inputs (Level 3). Such reconciliation, separately presenting changes during the period, at a minimum, may include: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income, and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset and liability. Contingent Payment Arrangements Affiliate Equity Repurchase Obligations Other Expense, Net Other Operating Income (Expense) [Member] Level 3 reconciliation of assets and liabilities Fair Value, Assets and Liabilities, Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] -- None. No documentation exists for this element. -- Changes in level 3 assets and liabilities Fair Value, Assets and Liabilities, Measured on Recurring Basis, Unobservable Input Reconciliation Calculation [Roll Forward] -- None. No documentation exists for this element. -- Balance, beginning of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Net realized and unrealized (gains) losses Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings and Other Comprehensive Income (Loss) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings and Other Comprehensive Income (Loss) Purchases and issuances Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Purchases And Issuances Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Purchases And Issuances Settlements and reductions Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements And Reductions Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements And Reductions Balance, end of period Net change in unrealized (gains) losses relating to instruments still held at the reporting date Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss) Losses resulting from changes in expected payments Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings and Other Comprehensive Income (Loss) From Changes in Expected Payments Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings and Other Comprehensive Income (Loss) From Changes in Expected Payments Accretion expenses Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings and Other Comprehensive Income (Loss), Accretion Expense Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings and Other Comprehensive Income (Loss), Accretion Expense Statement of Comprehensive Income [Abstract] Other comprehensive income (loss), net of tax: Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract] Foreign currency translation gain (loss) Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Change in net realized and unrealized gain (loss) on derivative financial instruments Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments and Tax Change in net unrealized gain (loss) on investment securities Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax Other comprehensive income (loss), net of tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive income (non-controlling interests) Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive income (controlling interest) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Schedule of Changes in Goodwill Schedule of Goodwill [Table Text Block] Schedule of Changes in, and the Components of, Acquired Client Relationships Schedule of Intangible Assets by Major Class [Table Text Block] Tabular disclosure of intangibles assets, in total and by major class, including the gross carrying amount and accumulated amortization. A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company. Schedule of Company's Derivative Assets and Liabilities Measured at Fair Value on Recurring Basis Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Schedule of Effect of Derivative Financial Instruments on the Consolidated Statements of Comprehensive Income and Statements of Income Derivative Instruments, Gain (Loss) [Table Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Carrying Value Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Senior notes Notes Payable, Fair Value Disclosure Convertible securities Convertible Debt, Fair Value Disclosures Schedule of Net Assets and Liabilities and Maximum Risk of Losses Related to Unconsolidated VIEs Schedule of Variable Interest Entities [Table Text Block] Assets Assets [Abstract] Cash and cash equivalents Receivables Accounts Receivable, Net Investments in marketable securities Goodwill Goodwill Acquired client relationships (net) Intangible Assets, Net (Excluding Goodwill) Fixed assets (net) Other investments Other Investments Other assets Other Assets Total assets Assets Liabilities and Equity Liabilities and Equity [Abstract] Payable and accrued liabilities Senior bank debt Senior notes Senior Notes Convertible securities Convertible Debt Deferred income tax liability (net) Other liabilities Other Liabilities Total liabilities Liabilities Commitments and contingencies (Note 10) Commitments and Contingencies Redeemable non-controlling interests Equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Common stock ($0.01 par value, 153.0 shares authorized; 58.5 shares outstanding in 2017 and 2018) Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss) Attributable to Parent, Net of Tax Accumulated change in equity applicable to the parent entity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. Retained earnings Retained Earnings (Accumulated Deficit) Total stockholders' equity before treasury stock Stockholders' Equity before Treasury Stock Less: Treasury stock, at cost (3.4 shares in 2017 and 6.5 shares in 2018) Treasury Stock, Value Total stockholders' equity Stockholders' Equity Attributable to Parent Non-controlling interests Other Noncontrolling Interests Total equity Total liabilities and equity Liabilities and Equity Changes in goodwill Goodwill [Roll Forward] Balance, beginning of period Foreign currency translation Goodwill, Foreign Currency Translation Gain (Loss) Balance, end of period Affiliate Equity -- None. No documentation exists for this element. -- Other Assets Other Assets [Member] Affiliate Equity Distributions paid to affiliate partners Affiliate equity, conditional right to put interest, period Affiliate Equity, Conditional Right to Put Interest, Period Affiliate Equity, Conditional Right to Put Interest, Period Payments to acquire interest in affiliates Payments to Acquire Businesses and Interest in Affiliates Issuance of interest in affiliates Proceeds from Divestiture of Businesses and Interests in Affiliates Due from affiliates Due from Affiliates Due to affiliates Due to Affiliate Payables and Accrued Liabilities Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block] Senior Bank Debt Debt Disclosure [Text Block] Investments, All Other Investments [Abstract] Other Investments Investment [Text Block] 2022 Senior Notes Senior Notes Five Point Two Five Percent Due 2022 [Member] Senior Notes5.25% Due 2022 Notes redeemed, canceled and retired Extinguishment of Debt, Amount Stated interest rate Number of senior notes outstanding Number of Debt Instruments, Outstanding Represents the number of debt instruments outstanding during the period. Junior Convertible Securities Junior Convertible Trust Preferred Securities [Member] Represents the junior convertible trust preferred securities. Principal amount at maturity Debt Instrument, Individual Security, Face Amount Debt Instrument, Individual Security, Face Amount Conversion ratio (in shares) Debt Instrument, Convertible, Conversion Ratio Conversion price (in usd per share) Debt Instrument, Convertible, Conversion Price Redemption closing price trigger (in usd per share) Debt Instrument, Convertible, Stock Price Trigger Number of trading days closing price has exceeded threshold Debt Instrument, Convertible, Threshold Trading Days Number of consecutive trading days Debt Instrument, Convertible, Threshold Consecutive Trading Days Deferred tax liability Deferred Tax Liability from Excess Interest Expense Calculation Represents the deferred taxes generated from the excess of the interest expense calculated under federal income tax regulations over interest expense as calculated for book purposes. 2019 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2020 Operating Leases, Future Minimum Payments, Due in Two Years 2021 Operating Leases, Future Minimum Payments, Due in Three Years 2022 Operating Leases, Future Minimum Payments, Due in Four Years 2023 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Consolidated rent expense Operating Leases, Rent Expense, Net Fixed Assets and Lease Commitments Fixed Assets and Lease Commitments Disclosure [Text Block] Disclosure of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Also includes the following disclosure for operating leases having initial or remaining non cancelable lease terms in excess of one year: (a) future minimum rental payments required as of the date of the latest balance sheet presented, in the aggregate and for each of the five succeeding fiscal years. Numerator Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Interest expense on convertible securities, net of taxes Interest on Convertible Debt, Net of Tax Net income (controlling interest), as adjusted Net Income (Loss) Available to Common Stockholders, Diluted Denominator Weighted Average Number of Shares Outstanding, Diluted [Abstract] Effect of dilutive instruments: Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Stock options and restricted stock units (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Convertible securities (in shares) Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities Average shares outstanding (diluted) (in shares) Schedule of Income Tax Provision Attributable to Controlling and Non-Controlling Interests Schedule of Components of Income Tax (Expense) Benefit by Controlling and Noncontrolling interests [Table Text Block] Tabular disclosure of the components of income tax expense attributable to controlling and non-controlling interests for each year presented including, income before income taxes and effective tax rate attributable to controlling interests. Schedule of Consolidated Provision for Income Taxes Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Components of Income before Income Taxes Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Schedule of Effective Income Tax Rate Computed Using Income before Income Taxes and Applying U.S. Federal Income Tax Rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of Components of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits Summary of Income Tax Contingencies [Table Text Block] Proceeds from sale of investments in marketable securities Proceeds from Sale and Maturity of Marketable Securities Net gains on sales of marketable securities Marketable Securities, Realized Gain (Loss) Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Schedule of Recent Share Repurchase Activity Class of Treasury Stock [Table Text Block] Schedule of Quarterly Results of Operations Quarterly Financial Information [Table Text Block] 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 Measured on a Recurring Basis Fair Value, Measurements, Recurring [Member] Level 1 Fair Value, Inputs, Level 1 [Member] Fair Value, Assets and Liabilities Measured on a Recurring and NonrecurringBasis Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Financial Assets Assets, Fair Value Disclosure [Abstract] Investments in marketable securities Investments, Fair Value Disclosure Derivative financial instruments Derivative Asset Financial Liabilities Liabilities, Fair Value Disclosure [Abstract] Contingent payment arrangements Obligations, Fair Value Disclosure Affiliate equity repurchase obligations Due to Related Parties, Fair Value Disclosure Due to Related Parties, Fair Value Disclosure Derivative financial instruments Derivative Liability Junior convertible securities Carrying Value Principal Amount at Maturity Debt instrument term Debt Instrument, Term Affiliate Equity Affiliate Equity [Text Block] Disclosures related to the conditional rights and obligations the company has to acquire Affiliate equity and the redeemable non-controlling interests on the consolidated balance sheets. Disclosure of the impact on the controlling interest's equity of changes in ownership at its Affiliates. Schedule of Intangible Assets, by Major Class [Table] Schedule of Intangible Assets, by Major Class [Table] Tabular disclosure of the major classes of acquired finite-lived and indefinite-lived intangible assets showing the amount, any significant residual value, weighted average amortization period, and other characteristics. A major class is composed of intangible assets that can be grouped together because they are similar, either by nature or by their use in the operations of the company. Intangible assets Intangible Asset [Line Items] -- None. No documentation exists for this element. -- Definite-lived Finite-lived Intangible Assets [Roll Forward] Beginning balance, gross book value Finite-Lived Intangible Assets, Gross Beginning balance, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Beginning balance, net book value Finite-Lived Intangible Assets, Net Intangible amortization and impairments Finite-Lived Amortization and Impairment Finite-Lived Amortization and Impairment Foreign currency translation Finite Lived Intangible Assets, Foreign Currency Translation Gain (Loss) Ending balance, gross book value Ending balance, accumulated amortization Ending balance, net book value Indefinite-lived Indefinite-lived Intangible Assets [Roll Forward] Beginning balance, net book value Indefinite-lived Intangible Assets (Excluding Goodwill) Intangible amortization and impairments Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) Foreign currency translation Indefinite-lived Intangible Assets, Foreign Currency Translation Gain (Loss) Ending balance, net book value Net Book Value Intangible Assets [Roll Forward] -- None. No documentation exists for this element. -- Beginning balance, net book value Intangible amortization and impairments Foreign currency translation Intangible Assets Net Excluding Goodwill Translation Adjustments Represents the amount of increase (decrease) to assets, excluding financial assets and goodwill, for foreign currency translation adjustments. Ending balance, net book value Geographic Information Segment Reporting Disclosure [Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] 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 [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Stock options and restricted stock units Employee Stock Options and Restricted Stock [Member] Employee Stock Options and Restricted Stock [Member] Convertible securities Convertible Debt Securities [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive securities excluded from computation of earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Schedule of Reconciliation of the Numerator and Denominator used in the Calculation of Basic and Diluted Earnings per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Diluted Earnings per Share Calculations, Excluding the Anti-dilutive Effect of Shares Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Statutory U.S. federal tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent State income taxes, net of federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Effect of foreign operations Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Percent Effect of changes in tax law, rates Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Reduction in carrying value of an equity method investment Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Percent Other Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Effective tax rate (controlling interest) Effect of income from non-controlling interests Effective Income Tax Rate Reconciliation, Noncontrolling Interest Income (Loss), Percent Effective tax rate Effective Income Tax Rate Reconciliation, Percent Statement [Table] Statement [Table] Additional Paid-In Capital Additional Paid-in Capital [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Retained Earnings Retained Earnings [Member] Treasury Stock at Cost Treasury Stock [Member] Statement Statement [Line Items] Increase (Decrease) in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance (in shares) Share-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Common stock issued under share-based incentive plans Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Shares repurchases Treasury Stock, Value, Acquired, Cost Method Forward equity Adjustments to Additional Paid in Capital, Other Common stock issued under forward equity agreement (in shares) Stock Issued During Period, Shares, New Issues Common stock issued under forward equity agreement Stock Issued During Period, Value, New Issues Issuance costs and other Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs and Other Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs and Other Dividends ($0.80 and $1.20 per share) Dividends, Common Stock, Cash Affiliate equity activity: Affiliate equity compensation Issuances Noncontrolling Interest, Increase from Subsidiary Equity Issuance Repurchases Noncontrolling Interest, Increase (Decrease) from Purchase of Interests Noncontrolling Interest, Increase (Decrease) from Purchase of Interests Changes in redemption value of Redeemable non-controlling interests Transfers to Redeemable non-controlling interests Noncontrolling Interest, Decrease from Transfers to Noncontrolling Interest Holders Noncontrolling Interest, Decrease from Transfers to Noncontrolling Interest Holders Capital contributions by Affiliate equity holders Noncontrolling Interest, Increase from Contributions from Affiliate Noncontrolling Interest, Increase from Contributions from Affiliate Distributions to non-controlling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Ending Balance (in shares) Document and Entity Information -- None. No documentation exists for this element. -- Entity Registrant Name Entity Central Index Key Document Type Document Period End Date Amendment Flag Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Public Float Entity Common Stock, Shares Outstanding Document Fiscal Year Focus Document Fiscal Period Focus Total fair value of share-based compensation awards vested Excess tax benefit recognized from share-based incentive plans Excess Tax Benefit from Share-based Compensation, Operating Activities Total compensation cost not yet recognized Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Weighted average period for recognition (in years) Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Schedule of Recent Share-Based Compensation Expense Schedule of Share-based Compensation Expense and Tax Benefit [Table Text Block] Tabular disclosure of share based compensation expense and the related tax benefit recorded by the entity. Schedule of Transactions of the Company's Stock Options Share-based Compensation, Activity [Table Text Block] Schedule of Assumptions Used to Determine Fair Value of Options Granted Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Schedule of Transactions of the Company's Restricted Stock Schedule of Nonvested Share Activity [Table Text Block] Fair Value, Measurements, Recurring Other Investments Other Investments [Member] Assets Derivative Asset, Fair Value, Gross Asset Liabilities Derivative Liability, Fair Value, Gross Liability Business and Summary of Significant Accounting Policies Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Foreign currency translation adjustment Change in net realized and unrealized gain (loss) on derivative financial instruments Pre-Tax Other Comprehensive Income (Loss), before Tax Tax Benefit (Expense) Other Comprehensive Income (Loss), Tax Schedule of Affiliate Equity Compensation Expense Summary of Affiliate Equity Compensation Expense [Table Text Block] Summary of Affiliate Equity Compensation Expense [Table Text Block] Schedule of Affiliate Equity Unrecognized Compensation Expense Summary of Affiliate Equity Unrecognized Compensation Expense [Table Text Block] Summary of Affiliate Equity Unrecognized Compensation Expense [Table Text Block] Schedule of the Effect of Changes in the Company's Ownership Interest in its Affiliates on the Controlling Interest's Equity Schedule of Net Income (Loss) Attributable to Entity and Net Transfers with Noncontrolling Interest [Table Text Block] Represents a schedule of net income (loss) attributable to the entity and net transfers to non-controlling interest. Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Schedule of Changes in Equity Method Investments in Affiliates Equity Method Investments [Table Text Block] Schedule of Financial Information for Affiliates Accounted for Under the Equity Method Comprehensive Income Comprehensive Income (Loss) Note [Text Block] Building and leasehold improvements Building and Leasehold Improvements [Member] Represents the long lived, depreciable structure held for productive use, including office, production, storage and distribution facilities and depreciable asset that is an addition or improvement to assets held under a lease arrangement. Software Furniture and fixtures Furniture and Fixtures [Member] Land, improvements and other Land and Land Improvements [Member] Fixed assets Fixed assets, at cost Property, Plant and Equipment, Gross Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Fixed assets (net) Schedule of Fair Value of Financial Assets and Liabilities Measured on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of Changes in Level 3 Financial Assets and Liabilities Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Schedule of Quantitative Information Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Schedule of Investments Fair Value Measurement, Inputs Based on Net Assets [Table Text Block] Tabular disclosure of investments that rely on net asset value as their fair value, including the nature of the investment and any related liquidation restrictions. Schedule of Financial Liabilities not Carried at Fair Value Summary of Other Financial Liabilities Not Carried at Fair Value [Table Text Block] Summary of Other Financial Liabilities Not Carried at Fair Value [Table Text Block] Revenue Net income Assets Equity Method Investment, Summarized Financial Information, Current Assets Liabilities and Non-controlling interests Equity Method Investment, Summarized Financial Information, Current Liabilities Change in Equity Method Investments in Affiliates [Roll Forward] Change in Equity Method Investments in Affiliates [Roll Forward] Change in Equity Method Investments in Affiliates Balance, beginning of period Equity method earnings Income (Loss) from Equity Method Investments Before Amortization of Intangibles Income (Loss) from Equity Method Investments Before Amortization of Intangibles Equity method intangible amortization and impairments Equity Method Investment, Intangible Asset Amortization and Impairments Equity Method Investment, Intangible Asset Amortization and Impairments Distributions of earnings from equity method investments Investments Payments to Acquire Equity Method Investments Foreign currency translation Equity Method Investment, Realized Gain (Loss) on Foreign Currency Translation Equity Method Investment, Realized Gain (Loss) on Foreign Currency Translation Other Equity Method Investment, Other Increase (Decrease) Equity Method Investment, Other Increase (Decrease) Balance, end of period Schedule of Cost, Gross Unrealized Gains and Losses, and Fair Value of Investments Marketable Securities [Table Text Block] Income before income taxes Effect of Fourth Quarter Events [Table] Effect of Fourth Quarter Events [Table] Effect of Fourth Quarter Events [Line Items] Effect of Fourth Quarter Events [Line Items]