Income Tax Disclosure [Abstract] Schedule of components of income tax provision Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Components of deferred income tax expense (benefit) Components of deferred income tax expense (benefit) [Table Text Block] Tabular disclosure of the components of deferred income tax expense (or tax benefits) included in total income tax expense (or benefit) for each year presented. Schedule of effective income tax rate reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of deferred tax assets and liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule of unrecognized tax benefits Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Table] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Weighted average [Member] Weighted Average [Member] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Computer and communications software and equipment [Member] Computer And Communications Software And Equipment [Member] Long lived, depreciable assets used in the creation, maintenance, and utilization of information systems which include computers and peripherals, as well as capitalized costs of purchased software applications and capitalized costs to develop software for long-term internal use. Buildings and improvements [Member] Building and Building Improvements [Member] Leasehold improvements [Member] Leasehold Improvements [Member] Furniture and other equipment [Member] Furniture and Fixtures [Member] Leased land [Member] Other Capitalized Property Plant and Equipment [Member] Property and equipment Property, Plant and Equipment [Line Items] Estimated useful life Property, Plant and Equipment, Useful Life Land [Member] Land [Member] Compensation and related costs attributable to the development of computer software for internal use [Member] Software Development [Member] Property and equipment, gross Property, Plant and Equipment, Gross Less accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Total Property, Plant and Equipment, Net Property and equipment, additions Property, Plant and Equipment, Additions Revenues and Services [Abstract] Revenues and Services [Abstract] Revenue and Services [Table] Revenue and Services [Table] Summarization of information required and determined to be disclosed concerning advisory service revenues and the assets from which those revenues are derived, by customer and investment mandate. Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Sponsored U.S. mutual funds [Member] Sponsored Mutual Funds In U S [Member] Sponsored mutual funds in the U.S. Administrative and distribution services provided to sponsored U.S. mutual funds Revenues and Services [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Administrative fees Administrative Services Revenue Distribution and servicing fees Distribution Fees Stock Options [Abstract] Stock Options [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Employee global long-term incentive plan [Member] Employee Stock Based Compensation Programs [Member] Employee Stock-Based Compensation Programs Non-employee director [Member] Non Employee Director [Member] Non-employee director programs Schedule of Share-based Compensation Arrangements by Share-based Payment Award, Program [Axis] Schedule of Share-based Compensation Arrangements by Share-based Payment Award, Program [Axis] Pertinent data describing and reflecting disclosures pertaining to grants during the period in an equity-based compensation arrangement, by equity-based compensation program. Schedule of Share-based Compensation Arrangements by Share-based Payment Award, Program [Domain] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award Program [Domain] Pertinent data describing and reflecting disclosures pertaining to grants during the period in an equity-based compensation arrangement, by equity-based compensation program. Semiannual [Member] Semiannual [Member] Semiannual Programs New hire [Member] New Hire [Member] New Hire Programs Award Type [Axis] Equity Award [Domain] Stock option [Member] Employee Stock Option [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Compensation and related costs [Member] Compensation and related costs [Member] Compensation and related costs [Member] Stock-based compensation Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share based compensation nonvested awards compensation cost to be recognized, next calendar year Share based compensation nonvested awards compensation cost to be recognized, next calendar year A positive value represents the unrecognized cost of awards outstanding at the balance sheet date under share-based compensation plans that will be recognized during the next January through December period subsequent to the balance sheet date. Outstanding at December 31, 2014 Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Grants Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Expired Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period Outstanding at December 31, 2015 Exercisable at December 31, 2015 Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted-average exercise price of options outstanding at December 31, 2014 (in dollars per option) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Weighted-average exercise price of option grants (in dollars per option) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Weighted-average exercise price of options exercised (in dollars per option) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Weighted-average exercise price of options forfeited (in dollars per option) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Weighted-average exercise price of options expired (in dollars per option) Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Weighted-average exercise price of options outstanding at December 31, 2015 (in dollars per option) Weighted-average exercise price of options exercisable at December 31, 2015 (in dollars per option) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted-average remaining contractual term of options outstanding at December 31, 2015 Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Weighted-average remaining contractual term of options exercisable at December 31, 2015 Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Stock-based compensation expense (dollars) Allocated Share-based Compensation Expense Total intrinsic value of options exercised (dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Aggregate intrinsic value of in-the-money options outstanding (dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Aggregate intrinsic value of options exercisable (dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Earnings Per Share [Abstract] Earnings per share reconciliation Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Antidilutive securities Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Assets, Fair Value Disclosure [Abstract] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value, Liabilities Measured on Recurring Basis, Disclosure Items [Axis] Fair Value, Hierarchy [Axis] Fair Value, Liabilities Measured on Recurring Basis, Disclosure Items [Domain] Fair Value Hierarchy [Domain] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value by Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair value measurements Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Investments in sponsored funds Available-for-sale Securities, Equity Securities Investments held as trading Trading Securities Total Assets, Fair Value Disclosure, Recurring Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Rollforward of stock options Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Rollforward of nonvested restricted shares and restricted stock units Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Future stock-based compensation expense Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block] Stock-based compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Property and equipment table Property, Plant and Equipment [Table Text Block] Available-for-sale Securities [Abstract] Investments in sponsored funds reconciliation Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Stockholders' Equity Note [Abstract] Stockholders' equity Stockholders' Equity Note Disclosure [Text Block] Investments, All Other Investments [Abstract] Other investments Other Investments [Text Block] The entire disclosure that details the components of Other Investments included on the balance sheet. Document and Entity Information [Abstract] Document and Entity Information [Abstract] Document Type Document Type Document Period End Date Document Period End Date Current Fiscal Year End Date Current Fiscal Year End Date Document Fiscal Period Focus Document Fiscal Period Focus Document Fiscal Year Focus Document Fiscal Year Focus Entity Registrant Name Entity Registrant Name Entity Incorporation, State Country Name Entity Incorporation, State Country Name Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Listing, Par Value Per Share (in dollars per share) Entity Listing, Par Value Per Share Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Public Float (dollars) Entity Public Float Entity Common Stock, Shares Outstanding (shares) Entity Common Stock, Shares Outstanding Entity Central Index Key Entity Central Index Key Amendment Flag Amendment Flag Statement of Cash Flows [Abstract] Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Net income Net Income (Loss) Attributable to Parent Adjustments to reconcile net income to net cash provided by operating activities Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization of property and equipment Depreciation, Nonproduction Stock-based compensation expense Realized gains on the dispositions of sponsored funds Available-for-sale Securities, Gross Realized Gains Net losses (gains) recognized on other investments Other Noncash Income (Expense) Net change in trading securities held by consolidated sponsored investment portfolios Proceeds from (Payments for) Trading Securities, Short-term Changes in accounts receivable and accrued revenue Increase (Decrease) in Accounts Receivable Changes in payables and accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Other changes in assets and liabilities Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Investments in sponsored funds Payments to Acquire Available-for-sale Securities, Equity Dispositions of sponsored funds Proceeds from Sale of Available-for-sale Securities, Equity Investments in debt securities held by savings bank subsidiary Payments to Acquire Available-for-sale Securities, Debt Proceeds from debt securities held by savings bank subsidiary Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Additions to property and equipment Payments to Acquire Property, Plant, and Equipment Other investing activity Payments for (Proceeds from) Other Investing Activities Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Repurchases of common stock Payments for Repurchase of Common Stock Common share issuances under stock-based compensation plans Proceeds from stock options exercised, net of payments for repurchase of common stock for employee tax withholding obligations and strike price The cash inflow associated with the amount received from holders exercising their stock options net of 1) shares swapped by the employee to pay the cost of related employee stock option awards and 2) cash outflows paid by the company to cover an employee's income tax withholding obligation as part of a net-share settlement of a share-based award. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately. A positive value represents cash inflows in excess of cash outflows listed. A negative value represents cash outflows in excess of the cash inflow described. Excess tax benefits from stock-based compensation plans Excess Tax Benefit from Share-based Compensation, Financing Activities Dividends Payments of Dividends Change in savings bank subsidiary deposits Increase (Decrease) in Time Deposits Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) [Abstract] Net change during year Cash and Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect At beginning of year Cash and Cash Equivalents, at Carrying Value At end of year Organization, Consolidation and Presentation of Financial Statements [Abstract] Nature of operations Nature of Operations [Text Block] Basis of preparation - basis of accounting Basis of Accounting, Policy [Policy Text Block] Basis of preparation - use of estimates Use of Estimates, Policy [Policy Text Block] Basis of preparation - reclassifications Reclassifications [Text Block] Consolidation Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block] New accounting pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Cash equivalents Cash and Cash Equivalents, Unrestricted Cash and Cash Equivalents, Policy [Policy Text Block] Investments in sponsored funds - available for sale Marketable Securities, Available-for-sale Securities, Policy [Policy Text Block] Other investments - cost and equity method investments Equity and Cost Method Investments, Policy [Policy Text Block] Other investments - trading securities Marketable Securities, Trading Securities, Policy [Policy Text Block] Concentrations of risk Concentration Risk Disclosure [Text Block] Property and equipment Property, Plant and Equipment, Policy [Policy Text Block] Goodwill Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block] Revenue recognition - investment advisory, distribution, and servicing fees Management and Investment Advisory Fees, Policy [Policy Text Block] Revenue recognition - taxes billed to clients Revenue Recognition Accounting Policy, Gross and Net Revenue Disclosure [Policy Text Block] Advertising Advertising Cost, Policy, Expensed Advertising Cost [Policy Text Block] Stock-based compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Earnings per share Earnings Per Share, Policy [Policy Text Block] Comprehensive income Comprehensive Income, Policy [Policy Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Number of distinct operating segments through which we internally conduct and manage our operations Number of Operating Segments Number of distinct operating segments through which we report our operations Number of Reportable Segments Number of reportable business segments and units to which goodwill is attributed (reporting unit) Number of Reporting Units Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Net unrealized holding gains (losses) [Member] Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Currency translation adjustments [Member] Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Accumulated other comprehensive income [Member] AOCI Attributable to Parent [Member] Schedule of Available-for-sale Securities, Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Investments in sponsored funds [Member] Equity Securities [Member] Debt securities held by savings bank subsidiary [Member] Debt Securities [Member] Equity share of investments held by UTI [Member] Proportionate Share Of Available For Sale Securities Held By Equity Method Investee [Member] Proportionate share of available for sale securities held by equity method investee [Member] Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss) [Line Items] Balances Stockholders' Equity Attributable to Parent Other comprehensive income (loss) before reclassifications and income taxes OCI, before Reclassifications, before Tax, Attributable to Parent Reclassification adjustments recognized in non-operating investment income Reclassification from AOCI, Current Period, before Tax, Attributable to Parent Other comprehensive income (loss) before income taxes Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Deferred tax benefits (income taxes) Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Total other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Balances Reclassification Adjustments [Abstract] Reclassification adjustments [Abstract] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Member] Reclassification out of Accumulated Other Comprehensive Income [Member] Reclassification Out Of Accumulated Other Comprehensive Income, Causes [Axis] Reclassification Out Of Accumulated Other Comprehensive Income, Causes [Axis] Causes for reclassification adjustments out of accumulated other comprehensive income Reclassification Out Of Accumulated Other Comprehensive Income, Causes [Domain] Reclassification Out Of Accumulated Other Comprehensive Income, Causes [Domain] [Domain] for Causes for reclassification adjustments out of accumulated other comprehensive income Capital gain distributions [Member] Receipt of capital gain distributions [Member] Receipt of capital gain distributions [Member] Dispositions of individual securities [Member] Sale Of Individual Securities [Member] Sale of individual securities Other than temporary impairments [Member] Other Than Temporary Impairments Recognized [Member] Other than temporary impairments recognized Sale of Subsidiary Gain (Loss) [Member] Sale of Subsidiary Gain (Loss) [Member] Equity Components [Axis] Net unrealized holding gains or losses [Member] Major Types of Debt and Equity Securities [Axis] Reclassification adjustment out of accumulated other comprehensive income Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Provision for income taxes Income Tax Expense (Benefit) Non-operating investment income Investment Income, Nonoperating Accounts Receivable, Net [Abstract] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Receivables from sponsored mutual funds Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts receivable for advisory fees and advisory-related administrative services Accounts Receivable, Net Fair Value Disclosures [Abstract] Fair value measurements Fair Value Disclosures [Text Block] Deferred tax benefit (income tax) impact of the components of other comprehensive income Comprehensive Income (Loss) [Table Text Block] Changes in accumulated other comprehensive income Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Investment Income, Interest and Dividend [Abstract] Schedule of Investment Income, Reported Amounts, by Category [Table] Investment Income [Table] Schedule of Investment Income, Reported Amounts, by Category [Axis] Investment Type [Axis] Investment Income, Categories [Domain] Investments [Domain] Investment income Net Investment Income [Line Items] Dividends, excluding capital gain distributions Investment Income, Dividend Risks and Uncertainties [Abstract] Concentration Risk [Table] Concentration Risk [Table] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Geographic concentration [Member] Geographic Concentration [Member] Reflects the percentage of a disclosed value in notes to the financial statements in the period from one or more specified geographic areas is to a corresponding consolidated amount. Revenues and services concentration Concentration Risk [Line Items] Concentration risk, additional characteristic Concentration Risk, Additional Characteristic Concentration risk, percentage Concentration Risk, Percentage Concentration risk, benchmark description Concentration Risk, Benchmark Description Other investment portfolios [Member] Other Portfolios [Member] Other portfolios Investment Mandate [Axis] Investment Mandate [Axis] Segregates the information included within the table to which this axis relates by the underlying investment mandate. Investment Mandate [Domain] Investment Mandate [Domain] Segregates the information included within the table to which this axis relates by the underlying investment mandate. Stock and blended asset [Member] Stock And Blended Asset [Member] Stock and blended asset [Member] Bond and money market [Member] Bond And Money Market [Member] Bond and money market [Member] Bond, money market, and stable value [Member] Bond Money Market And Stable Value [Member] Bond, money market and stable value [Member] Investment advisory services Revenues from advisory services Investment Advisory Fees Average assets under management Assets under Management, Average Balance Period end assets under management Assets under Management, Carrying Amount Stockholders' Equity Note [Table] Stockholders' Equity Note [Table] Stockholders' Equity Note [Table] Dividends [Axis] Dividends [Axis] Dividends [Domain] Dividends [Domain] Regular cash dividend [Member] Ordinary Dividend [Member] Ordinary Dividend [Member] Special dividend [Member] Special Dividend [Member] Special Dividend [Member] Stockholders' Equity Note Stockholders' Equity Note [Line Items] [Line Items] for Stockholders' Equity Note [Table] Common shares authorized for future repurchase (shares) Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased Cash dividends declared per share Common Stock, Dividends, Per Share, Declared Cash dividends paid per share Common Stock, Dividends, Per Share, Cash Paid Restricted stockholders' equity (dollars) Amount of Restricted Net Assets for Consolidated and Unconsolidated Subsidiaries Quarterly Financial Information Disclosure [Abstract] Supplementary quarterly financial data Schedule of Quarterly Financial Information [Table Text Block] Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Cash and cash equivalents Accounts receivable and accrued revenue Other investments Other Investments Property and equipment, net Goodwill Goodwill, Gross Other assets Prepaid Expense and Other Assets Total assets Assets LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] Liabilities Liabilities [Abstract] Accounts payable and accrued expenses Accounts Payable and Other Accrued Liabilities Accrued compensation and related costs Employee-related Liabilities Income taxes payable Accrued Income Taxes Total liabilities Liabilities Commitments and contingent liabilities Commitments and Contingencies Stockholders' equity Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, undesignated, $.20 par value - authorized and unissued 20,000,000 shares Preferred Stock, Value, Issued Common stock, $.20 par value - authorized 750,000,000; issued 261,110,000 shares at December 31, 2014 and 250,469,000 at December 31, 2015 Common Stock, Value, Issued Additional capital in excess of par value Additional Paid in Capital, Common Stock Retained earnings Retained Earnings, Unappropriated Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders' equity Total liabilities and stockholders' equity Liabilities and Equity Shares Authorized For Stock-Based Compensation Programs [Abstract] Shares Authorized For Stock-Based Compensation Programs [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Stock-based compensation plan [Member] Stock Compensation Plan [Member] Employee stock purchase plan [Member] Employee Stock Purchase Plan [Member] Employee stock purchase plan Shares of unissued common stock authorized for issuance Share Based Compensation Arrangement By Share Based Payment Award, Remaining Number of Shares Authorized The difference between the maximum number of shares (or other type of equity) originally authorized for issuance under the plan (including the effects of amendments and adjustments), and the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan. Shares authorized for issuance Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract] Defined Contribution Plan [Table] Defined Contribution Plan [Table] Retirement Plans Defined Contribution Plan Disclosure [Line Items] Expense recognized for defined contribution retirement plans Defined Contribution Plan, Cost Recognized Less net income allocated to outstanding restricted stock and stock unit holders (basic) Participating Securities, Distributed and Undistributed Earnings (Loss), Basic Less net income allocated to outstanding restricted stock and stock unit holders (diluted) Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted Net income allocated to common stockholders (basic) Net Income (Loss) Available to Common Stockholders, Basic Net income allocated to common stockholders (diluted) Net Income (Loss) Available to Common Stockholders, Diluted Weighted-average common shares Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Outstanding (shares) Weighted Average Number of Shares Outstanding, Basic Outstanding assuming dilution (shares) Weighted Average Number of Shares Outstanding, Diluted Weighted-average outstanding stock options excluded (options) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Effect Of Special Cash Dividend [Abstract] Effect Of Special Cash Dividend [Abstract] Effect of special cash dividend Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Description and Terms Adjustment to options outstanding on the special dividend's ex-dividend date Share Based Compensation Arrangement By Share Based Payment Award Plan Modification Incremental Options Outstanding The increase in options outstanding due to a modification of all oustandiing options. The modification occured on the ex-dividend date as a result of a special dividend. Incremental compensation expense Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Stock and blended asset funds [Member] Equity Funds [Member] Bond funds [Member] Fixed Income Funds [Member] Investments in sponsored funds - available-for-sale Schedule of Available-for-sale Securities [Line Items] Aggregate cost Available-for-sale Equity Securities, Amortized Cost Basis Unrealized holding gains Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax Unrealized holding losses Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax Aggregate fair value Fund holdings with temporary unrealized holding losses (number of securities) Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Unrealized holding losses at period end are attributable to fund holdings with an aggregate fair value of Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Fund holdings with continuous loss position for 12 months or more (number of securities) Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year Fund holdings in a continuous loss position for 12 months or more with an aggregate fair value of Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Unrealized holding losses in continuous unrealized loss position for 12 months or more Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Income taxes Income Tax Disclosure [Text Block] Components of other investments Components of Other Investments [Text Block] Tabular disclosure of the components of other investments, including those accounted for under the cost, equity and other methods. Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Common stock [Member] Common Stock [Member] Additional capital in excess of par value [Member] Additional Paid-in Capital [Member] Retained earnings [Member] Retained Earnings, Unappropriated [Member] Statement Statement [Line Items] Balances (shares) Common Stock, Shares, Outstanding Other comprehensive income (loss), net of tax Dividends Dividends, Cash Common stock-based compensation plans activity Share-based Compensation [Abstract] Shares issued upon option exercises (shares) Stock Issued During Period Stock Options Exercised Net Of Shares For Tax Withholding Strike Price A positive value represents the number of shares of stock issued during the period as a result of option exercises, net of shares withheld for the payment of withholding taxes and shares swapped for payment of strike price. Shares issued upon option exercises Stock Issued During Period Value Stock Options Exercised Net of Tax Withholdings Strike Price A positive value represents the value of stock issued as a result of the exercise of stock options less values of underlying shares swapped by the employee to pay the cost of the related stock option award and withheld to pay related income tax obligations. Restricted shares issued, net of shares withheld for taxes (shares) Restricted Stock, Shares Issued Net of Shares for Tax Withholdings Restricted shares issued, net of shares withheld for taxes Restricted Stock, Value, Shares Issued Net of Tax Withholdings Shares issued upon vesting of restricted stock units, net of shares withheld for taxes (shares) Stock Issued During Period, Shares, Other Shares issued upon vesting of restricted stock units, net of shares withheld for taxes Stock Issued During Period, Value, Other Forfeiture of restricted awards (shares) Stock Issued During Period, Shares, Restricted Stock Award, Forfeited Forfeiture of restricted awards Stock Issued During Period, Value, Restricted Stock Award, Forfeitures Net tax benefits Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net Stock-based compensation expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Restricted stock units issued as dividend equivalents Dividends, Share-based Compensation, Paid-in-kind Common shares repurchased (shares) Stock Repurchased During Period, Shares Common shares repurchased Stock Repurchased During Period, Value Balances (shares) Information about Receivables, Revenues, and Services [Abstract] Information about Receivables, Revenues, and Services Components of revenues from advisory services Components of Investment Advisory Fees [Text Block] Tabular disclosure of the components of revenue recognized in the period for schedule-based fees earned for management of mutual funds based on average daily net assets and other investment management and advisory fees earned on other client portfolios based on asset valuations. Components of assets under management Components of Assets Under Management [Text Block] Tabular disclosure of the components of average assets under management and period end assets under management. Assets under management represents the market value of assets an investment adviser manages on behalf of investors and is the basis for determining investment advisory fee revenue. Components of other fees Components Of Other Fees [Table Text Block] Tabular disclosure of the components of revenue recognized in the period for other fees earned from sponsored mutual funds in the United States. Cash and Cash Equivalents [Abstract] Cash equivalent investments in our sponsored money market mutual funds Money Market Funds, at Carrying Value Other comprehensive income and accumulated other comprehensive income Comprehensive Income (Loss) Note [Text Block] Leases, Operating [Abstract] Rental expense Operating Leases, Rent Expense Future minimum operating lease payments Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] Future minimum operating lease payments, due in 2016 Operating Leases, Future Minimum Payments Due, Next Twelve Months Future minimum operating lease payments, due in 2017 Operating Leases, Future Minimum Payments, Due in Two Years Future minimum operating lease payments, due in 2018 Operating Leases, Future Minimum Payments, Due in Three Years Future minimum operating lease payments, due in 2019 Operating Leases, Future Minimum Payments, Due in Four Years Future minimum operating lease payments, due in 2020 Operating Leases, Future Minimum Payments, Due in Five Years Future minimum operating lease payments, due in later years Operating Leases, Future Minimum Payments, Due Thereafter Selected Quarterly Financial Information [Abstract] Net revenues Revenues, Net of Interest Expense Basic earnings on common stock Earnings Per Share, Basic Diluted earnings on common stock Earnings Per Share, Diluted Summary of significant accounting policies Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Duration of fund holding unrealized loss between quarter-ends generally presumed to represent other than temporary impairment Available For Sale Equity Securities In Unrealized Loss Position, Qualitative Disclosure, Other Than Temporary Impairment Policy, Loss Term The period of time between quarter ends after which available-for-sale equity securities in a continuous unrealized loss position will generally be considered other than temporarily impaired under the company's impairment policy. Disclosure Text Block Supplement [Abstract] Other disclosures Additional Financial Information Disclosure [Text Block] Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosures [Abstract] Accumulated Other Comprehensive Income (Loss) [Table] Net deferred tax benefits (income taxes) before reclassification adjustments Other Comprehensive Income (Loss) before Reclassifications, Tax Net deferred tax benefits on reclassification adjustments from accumulated other comprehensive income Reclassification from AOCI, Current Period, Tax Total deferred tax benefits (income taxes) Income Tax Uncertainties [Abstract] Balance at beginning of year Unrecognized Tax Benefits that Would Impact Effective Tax Rate Changes in tax positions related to current year Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Decreases in tax positions related to prior years Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Increases in tax positions related to prior years Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Changes in tax positions related to expired statute of limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Balance at end of year Net interest payable Unrecognized Tax Benefits, Interest on Income Taxes Accrued Supplementary quarterly financial data (unaudited) Quarterly Financial Information [Text Block] Fair value measurements table Fair Value, Assets Measured on Recurring Basis [Table Text Block] Components of Income Tax Provision [Table] Components of Income Tax Provision [Table] Disclosure of the components of our income tax provision during the period, including U.S. federal, foreign, state and local, and deferred taxes, by components, as well as a reconciliation of the statutory federal rate to the effective income tax rate. Deferred Tax Expense (Benefit) [Axis] Deferred Tax Expense (Benefit) [Axis] Description and amount of the components of deferred tax expense (benefit), by component. Deferred Tax Expense (Benefit) [Domain] Deferred Tax Expense Benefit [Domain] Identifies the component of deferred tax expense or benefit. Related to property and equipment [Member] Relating To Property And Equipment [Member] Relating to property and equipment [Member] Related to stock-based compensation [Member] Relating To Recognition Of Stock Based Compensation Expense [Member] Relating to the recognition of stock-based compensation expense [Member] Related to accrued and deferred compensation [Member] Relating to accrued compensation [Member] Relating to accrued compensation [Member] Related to other-than-temporary impairments of sponsored fund investments [Member] Attributable To Other Than Temporary Impairments Recognized On Our Sponsored Mutual Fund Investments [Member] Attributable to other than temporary impairments recognized on our sponsored mutual fund investments [Member] Relating to other [Member] Relating to Other [Member] Relating to other [Member] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Components of income tax provision Components of income tax provision [Line Items] Components of income tax provision [Line Items] Current income taxes Current Income Tax Expense (Benefit), Continuing Operations [Abstract] U.S. federal Current Federal Tax Expense (Benefit) State and local Current State and Local Tax Expense (Benefit) Foreign Current Foreign Tax Expense (Benefit) Deferred income taxes (tax benefits) Deferred Income Tax Expense (Benefit) Total Supplemental savings plan deferral period Supplemental Savings Plan Deferral Period Duration for which certain employees can defer their cash incentive compensation under a supplemental savings plan, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Statutory U.S. federal income tax rate (percentage) Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent State income taxes for current year, net of federal income tax benefits (percentage) Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Other items (percentage) Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Effective income tax rate (percentage) Effective Income Tax Rate Reconciliation, Percent Stockholders' equity Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized Preferred Stock, Shares Authorized Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Discontinued Operations and Disposal Groups [Abstract] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Groups, Including Discontinued Operations, Name [Domain] Disposal Group Name [Domain] Savings bank subsidiary [Member] Savings Bank Subsidiary [Member] Savings Bank Subsidiary [Member] Non-operating investment income [Member] Investment Income [Member] Source of Gain [Axis] Source of Gain [Axis] information by source of gain. Source of Gain [Domain] Source of Gain [Domain] [Domain] for information by source of gain. Portion of purchase price in excess of subsidiary net book value [Member] Portion Of Purchase Price In Excess Of Subsidiary Net Book Value [Member] Portion of purchase price in excess of subsidiary net book value [Member] Savings bank subsidiary Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Capital stock of subsidiary sold (percentage) Sale Of Subsidiary By Parent Percentage Ownership Sold A positive value represents the percentage ownership in a subsidiary sold during the period, Gain recognized Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax Proceeds from sale of subsidiary Proceeds from Divestiture of Interest in Consolidated Subsidiaries Income Statement [Abstract] Revenues Revenues, Net of Interest Expense [Abstract] Investment advisory fees Administrative fees Distribution and servicing fees Net revenue of savings bank subsidiary Interest Income (Expense), Net Net revenues Operating expenses Operating Expenses [Abstract] Compensation and related costs Labor and Related Expense Advertising and promotion Marketing and Advertising Expense Distribution and servicing costs Noninterest Expense Distribution and Servicing Fees Occupancy and facility costs Other General and Administrative Expense Other operating expenses Other Cost and Expense, Operating Total operating expenses Operating Expenses Net operating income Operating Income (Loss) Non-operating investment income Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Net income Earnings per share on common stock Basic (in dollars per share) Diluted (in dollars per share) Investments in sponsored funds - available-for-sale Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Statement of Comprehensive Income [Abstract] Other comprehensive income (loss) Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent [Abstract] Net unrealized holding gains (losses) on available-for-sale investments Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Reclassification adjustments recognized in non-operating investment income Reclassification Adjustments Recognized in Non-operating Investment Income [Abstract] Reclassification adjustments recognized in non-operating investment income [Abstract] Capital gain distributions Other Comprehensive Income (Loss) Adjustment For Capital Gain Distribution Received Before Tax 1 A positive value represents the before tax reduction in other comprehensive income upon reclassification of capital gain distributions included in non-operating income. Net gains realized on dispositions determined using average cost Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Other-than-temporary impairments Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, before Tax Net unrealized holding gains derecognized upon the sale of savings bank subsidiary Other Comprehensive Income Loss Reclassification Adjustment From AOCI For Sale Of Entity Holding Securities Before Tax Amount before tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) derecognized upon the sale of the entity holding the securities. Total reclassification adjustments Other Comprehensive Income (Loss) Reclassification Adjustment From AOCI For Available For Sale Securities Before Tax Amount before tax of all reclassification adjustments from accumulated other comprehensive income for unrealized gains (losses) related to available-for-sale securities. Total net unrealized holding gains (losses) recognized in other comprehensive income Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent Currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax Reclassification loss recognized in non-operating investment income upon deconsolidation of sponsored fund subsidiary Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax Total currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Parent Total comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Other Investments [Table] Other Investments [Table] Summarization of information required and determined to be disclosed concerning all Other Investments. The information is summarized by accounting treatment and separately identifies significant investees. Schedule of Equity Method Investment, Equity Method Investee, Name [Axis] Investment, Name [Axis] Equity Method Investee, Name [Domain] Investment, Name [Domain] 26% Interest in UTI Asset Management Company Limited (India) [Member] UTI Asset Management Company India [Member] UTI Asset Management Company India [Member] Sponsored fund investments [Member] Sponsored fund equity method investments [Member] Sponsored fund equity method investments [Member] Other equity method investments [Member] Other Equity Method Investments [Member] Other equity method investments Schedule of Securities Held as Trading [Axis] Schedule of Securities Held as Trading [Axis] This axis disagregates securities held as trading into general categories of investments required or determined to be disclosed. Schedule Of Securities Held As Trading [Domain] Schedule Of Securities Held As Trading [Domain] This domain disagregates securities held as trading into general categories of investments required or determined to be disclosed. Sponsored fund investments [Member] Sponsored Mutual Fund Investments [Member] Investments in our sponsored mutual fund products. Securities held by consolidated sponsored investment portfolios [Member] Securities Held By Consolidated Sponsored Mutual Funds [Member] Securities held by consolidated sponsored mutual funds [Member] Other investments Other Investments [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Cost method investments Cost Method Investments Equity method investments Equity Method Investments Investments held as trading U.S. Treasury note Held-to-maturity Securities Total Equity method investment (ownership percentage) Equity Method Investment, Ownership Percentage Deconsolidation value Deconsolidation Value A positive value represents the carrying value of the assets and liabilities deconsolidated during the period as valued on the date that the parent no longer had a controlling financial interest in the subsidiary. Loss recognized upon deconsolidation Deconsolidation, Gain (Loss), Amount Commitment to make additional contributions to various investment partnerships Other Commitment Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Assumptions used in option pricing model and grant date fair value of options Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Share-based Arrangements with Employees and Nonemployees [Abstract] Employee Stock-Based Compensation Programs [Member] Restricted shares and restricted stock units [Member] Restricted Stock And Restricted Stock Units [Member] Shares and stock units that an entity has not yet issued because the agreed-upon consideration, such as employee services, has not yet been received. Stock options [Member] Stock awards and options Stockholder-approved plans (plans) Stockholder approved plans for stock options The number of stockholder approved plans under which qualified incentive and nonqualified fixed stock options are granted. Shares available for future grant (shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Graded vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Term Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Weighted-average grant-date fair value per option awarded (in dollars per option) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Expected life assumption Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Expected volatility assumption Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Dividend yield assumption Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Risk-free interest rate assumption Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Earnings per share calculations Earnings Per Share [Text Block] Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Abstract] First quarter 2016 Share based compensation nonvested awards compensation cost to be recognized, next quarter A positive value represents the unrecognized cost of awards outstanding at the balance sheet date under share-based compensation plans that will be recognized during the first quarter following the balance sheet date. Second quarter 2016 Share based compensation nonvested awards compensation cost to be recognized, second quarter A positive value represents the unrecognized cost of awards outstanding at the balance sheet date under share-based compensation plans that will be recognized during the second quarter following the balance sheet date. Third quarter 2016 Share based compensation nonvested awards compensation cost to be recognized, third quarter A positive value represents the unrecognized cost of awards outstanding at the balance sheet date under share-based compensation plans that will be recognized during the third quarter following the balance sheet date. Fourth quarter 2016 Share based compensation nonvested awards compensation cost to be recognized, fourth quarter A positive value represents the unrecognized cost of awards outstanding at the balance sheet date under share-based compensation plans that will be recognized during the fourth quarter following the balance sheet date. Total 2016 2017 through 2021 Share based compensation nonvested awards compensation cost to be recognized, between second calendar year and vest date A positive value represents the unrecognized cost of awards outstanding at the balance sheet date under share-based compensation plans that will be recognized in the second January subsequent to the balance sheet date through each awards vesting date. Total Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Net deferred tax asset (liability) and other tax disclosures [Table] Net deferred tax asset (liability) and other tax disclosures [Table] Disclosure of the components of the net deferred tax asset or liability recognized in an entity's statement of financial position as well as other tax disclosures. Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other assets [Member] Other Assets [Member] Net deferred tax asset (liability) and other tax disclosures Net deferred tax asset (liability) and other tax disclosures [Line Items] [Line Items] for Disclosure of the components of the net deferred tax asset or liability recognized in an entity's statement of financial position as well as other tax disclosures. Deferred tax liabilities Deferred Tax Liabilities, Gross [Abstract] Related to property and equipment Deferred Tax Liabilities, Property, Plant and Equipment Recognized in other comprehensive income on net unrealized holding gains Deferred Tax Liabilities, Other Comprehensive Income Other Deferred Tax Liabilities, Other Total deferred tax liability Deferred Tax Liabilities, Gross Deferred tax assets Deferred Tax Assets, Gross [Abstract] Related to stock-based compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Related to other-than-temporary impairments of investments in sponsored funds Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Impairment Losses Related to accrued compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Other Recognized in other comprehensive income on currency translation adjustment Deferred Tax Assets, Other Comprehensive Loss Other Deferred Tax Assets, Other Total deferred tax asset Deferred Tax Assets, Gross Net deferred tax asset Deferred Income Tax Assets, Net Estimated unremitted earnings of foreign subsidiaries, for which a deferred tax liability has not been recognized Undistributed Earnings of Foreign Subsidiaries Tax refund receivables Income Taxes Receivable Net income taxes paid included in cash outflows from operating activities Income Taxes Paid, Net Additional income tax benefits from stock-based compensation plans activity that reduced the amount of income taxes that would have otherwise been payable Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options Cash equivalents Cash and Cash Equivalents Disclosure [Text Block] Information about receivables, revenues, and services Information About Receivables Revenues And Services Text Block This element is used to indicate facts reported for the continuing operations of a business entity including disclosure of receivables from sponsored mutual funds for both advisory fees and administrative services provided. This element also includes disclosure of the components of investment advisory fees and administrative fees earned as well as the components of average assets and period end assets under management. Restricted shares and stock units [Abstract] Restricted shares and stock units [Abstract] Award Type [Axis] Equity Award [Domain] Restricted shares [Member] Restricted Stock [Member] Restricted stock units [Member] Restricted Stock Units (RSUs) [Member] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Time based vesting [Member] Time Based [Member] Time Based [Member] Performance based vesting [Member] Performance Based [Member] Performance Based [Member] Schedule of Share-based Compensation Arrangement by Share-based payment award, Performance Condition Status [Axis] Schedule of Share-based Compensation Arrangement by Share-based payment award, Performance Condition Status [Axis] Schedule of Share-based Compensation Arrangement by Share-based payment award, Performance Condition Status [Axis] Schedule of Share-based Compensation Arrangement by Share-based payment award, Performance Condition Status [Domain] Schedule of Share-based Compensation Arrangement by Share-based payment award, Performance Condition Status [Domain] [Domain] for Schedule of Share-based Compensation Arrangement by Share-based payment award, Performance Condition Status [Axis] Performance threshold met [Member] Performance Conditions Met [Member] Performance Conditions Met [Member] Nonvested at December 31, 2014 Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (value at vest date was $60.1 million) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Value at vest date (dollars) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Nonvested at December 31, 2015 Weighted-average fair value of nonvested restricted shares and restricted stock units at December 31, 2014 (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Weighted-average fair value of restricted shares and restricted stock units granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Weighted-average fair value of restricted shares and restricted stock units vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Weighted-average fair value of restricted shares and restricted stock units forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Weighted-average fair value of nonvested restricted shares and restricted stock units at December 31, 2015 (in dollars per share) Vested stock units Vested restricted stock units The number of vested but unsettled awards (other than option plans) for which the company is obligated to issue equity instruments or transfer assets to a non-employee director. For these awards the non-employee director has satisfied the service or performance criteria necessary to gain title to the underlying shares but will not receive the shares until separation from the board. Property and equipment Property, Plant and Equipment Disclosure [Text Block]