Accounting Policies [Abstract] Consolidation Consolidation, Policy [Policy Text Block] Reportable Segment Segment Reporting, Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Compensation and Benefits Compensation Related Costs, Policy [Policy Text Block] Share-Based Compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Earnings Per Share Earnings Per Share, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Cash and Cash Equivalents, Cash and Securities Segregated Under Federal and Other Regulations, Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Receivable From and Payables to Clients Receivable From and Payables to Clients [Policy Text Block] The net change during the reporting period in receivables and payables to clients, which includes amounts on cash and margin transactions, including interest on certain client balances. Advisor Loans [Policy Text Block] Advisor Loans [Policy Text Block] Disclosure of accounting policy for loan commitments extended to advisors, including the form of loans and assumptions used to extend credit. Receivables Receivables, Policy [Policy Text Block] Securities Owned and Securities Sold, But Not Yet Purchased Marketable Securities, Policy [Policy Text Block] Securities Borrowed Securities Borrowed and Loaned Policy [Policy Text Block] Fixed Assets Property, Plant and Equipment, Policy [Policy Text Block] Goodwill and Other Intangible Assets Goodwill and Intangible Assets, Policy [Policy Text Block] Debt Issuance Costs Debt, Policy [Policy Text Block] Derivative Financial Instruments Derivatives, Policy [Policy Text Block] Fair Value of Debt Instruments Fair Value of Debt Instruments [Policy Text Block] Disclosure of accounting policy for determining the fair value of debt instruments. Commitments and Contingencies Commitments and Contingencies, Policy [Policy Text Block] Leasehold Financing Obligation Policy [Policy Text Block] Leasehold Financing Obligation Policy [Policy Text Block] Disclosure of accounting policy for leasehold financing obligation. The leasehold financing obligation is a legal obligation associated with the construction and development of a long-lived asset. Recently Issued Accounting Pronouncements Description of New Accounting Pronouncements Not yet Adopted [Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [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] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Future amortization expense Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] 2015 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2016 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2017 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2018 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2019 Finite-Lived Intangible Assets, Amortization Expense, Year Five Thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Net Carrying Value Finite-Lived Intangible Assets, Net Investments, Debt and Equity Securities [Abstract] Held-to-Maturity Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Payables and Accruals [Abstract] Accounts Payable and Accrued Liabilities Accounts Payable and Accrued Liabilities Disclosure [Text Block] Income Tax Disclosure [Abstract] Summary of provision for income taxes Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Summary of effective income tax rate reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Components of the net deferred income taxes Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Summary of gross unrecognized tax benefits including interest and penalties reconciliation Summary of Income Tax Contingencies [Table Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Subsequent Event [Table] Subsequent Event [Table] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Dividends Payable, Date Declared Dividends Payable, Date Declared Dividends Payable, Amount Per Share Dividends Payable, Amount Per Share Dividends Payable, Date to be Paid Dividends Payable, Date to be Paid Dividends Payable, Date of Record Dividends Payable, Date of Record Investment Repurchase Agreement, Repurchase Date Investment Repurchase Agreement, Repurchase Date Stock Repurchased During Period, Shares Stock Repurchased During Period, Shares Treasury Stock Acquired, Average Cost Per Share Treasury Stock Acquired, Average Cost Per Share Brokers and Dealers [Abstract] Collateral Securities Repledged, Delivered, or Used Collateral Securities Repledged, Delivered, or Used Collateral security Customer Securities for which Entity has Right to Sell or Repledge, Fair Value Amount pledged with client-owned securities Customer Securities for which Entity has Right to Sell or Repledge, Fair Value of Securities Sold or Repledged Remaining collateral securities that can be sold, re-pledged or loaned Fair Value of Securities Received as Collateral that Can be Resold or Repledged Security Owned and Pledged as Collateral, Fair Value [Abstract] Security Owned and Pledged as Collateral, Fair Value [Abstract] Trading securities pledged to clearing organizations Security Owned and Pledged as Collateral, Fair Value Leasehold Financing Obligation Leasehold Financing Obligation Leasehold Financing Obligation Fair Value Disclosures [Abstract] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] National Retirement Partners [Member] National Retirement Partners [Member] National retirement partners. Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [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, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Payment of contingent consideration Payment of Contingent Consideration Obligation Cash paid related to the Company's contingent consideration obligation 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 and warrants [Member] Stock options and warrants [Member] Stock options and warrants [Member] Restricted stock awards and restricted stock units Restricted Stock [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Vesting Period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Expiration Period Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Share-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Long-term Debt, Gross Long-term Debt, Gross Debt Instrument, Fair Value Disclosure Debt Instrument, Fair Value Disclosure Receivables [Abstract] Receivables [Abstract] Free credit balances held Free credit balances held Represents free credit balances which are held pending re-investment by the clients. Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Receivable Type [Axis] Receivable Type [Axis] Receivable [Domain] Receivable [Domain] Receivables from clients [Member] Receivables from clients [Member] Receivables from clients for amounts due on cash and margin transactions [Member] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Allowance for Doubtful Accounts Receivable [Roll Forward] Allowance for Doubtful Accounts Receivable [Roll Forward] Beginning balance - January 1 Allowance for Doubtful Accounts Receivable Provision for doubtful accounts Provision for Doubtful Accounts Ending balance - December 31 Summary of amortized cost, gross unrealized loss, and fair value of securities held-to-maturity Held-to-maturity Securities [Table Text Block] Maturities of securities held-to-maturity Investments Classified by Contractual Maturity Date [Table Text Block] Earnings Per Share [Abstract] Basic and diluted earnings per share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Summary of activity in goodwill Schedule of Goodwill [Table Text Block] Components of intangible assets Schedule of Intangible Assets and Goodwill [Table Text Block] Amortization expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Property, Plant and Equipment [Abstract] Fixed Assets Property, Plant and Equipment Disclosure [Text Block] Finite-lived Intangible Assets Acquired Finite-lived Intangible Assets Acquired Goodwill [Roll Forward] Goodwill [Roll Forward] Goodwill, beginning balance Goodwill Goodwill acquired Goodwill, Acquired During Period Goodwill, ending balance Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Summary of Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Advisor Loans [Member] Advisor Loans [Member] Advisor Loans [Member] Statement, Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Statement [Line Items] Statement [Line Items] Allowance for Doubtful Accounts Receivable Accumulated amortization, Debt issuance costs Accumulated Amortization, Debt Issuance Costs Common stock, par value Common Stock, Par or Stated Value Per Share Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Treasury stock, shares Treasury Stock, Shares Compensation and Retirement Disclosure [Abstract] Employee and Advisor Benefit Plans Compensation and Employee Benefit Plans [Text Block] Document and Entity Information [Abstract] Entities [Table] Entities [Table] Entity Information [Line Items] Entity Information [Line Items] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Amendment Flag Amendment Flag Entity Filer Category Entity Filer Category Entity Public Float Entity Public Float Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Goodwill acquired during the period Intangible assets acquired during the period Total amortization expense of intangible assets Amortization of Intangible Assets Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party Transactions, by Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] TPG Capital [Member] TPG Capital [Member] TPG Capital Related Party Transaction [Line Items] Related Party Transaction [Line Items] Shareholder Percent Ownership in Company Shareholder Percent Ownership in Company Shareholder Percent Ownership in Company Related party revenues Revenue from Related Parties Related party expenses Related Party Transaction, Expenses from Transactions with Related Party Related party accounts payable Accounts Payable, Related Parties Related party accounts receivable Accounts Receivable, Related Parties Treasury stock purchases, shares Treasury Stock, Shares, Acquired Statement of Stockholders' Equity [Abstract] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-In Capital Additional Paid-in Capital [Member] Treasury Stock Treasury Stock [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Retained Earnings Retained Earnings [Member] BEGINNING BALANCE Stockholders' Equity Attributable to Parent BEGINNING BALANCE, shares Shares, Issued Net income and other comprehensive income, net of tax expense Comprehensive Income (Loss), Net of Tax, Attributable to Parent Net Income (Loss) Attributable to Parent Net Income (Loss) Attributable to Parent Issuance of common stock to settle restricted stock units Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Issuance of common stock to settle restricted stock units, shares Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Treasury stock purchases Treasury Stock, Value, Acquired, Cost Method Cash dividends on common stock Dividends, Common Stock, Cash Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Stock options exercises and other Stock Issued During Period, Value, Stock Options Exercised Stock options exercises and other, shares Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Excess tax benefits from share-based compensation Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net Share-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Share-based compensation, shares Stock Issued During Period, Shares, Share-based Compensation, Gross ENDING BALANCE ENDING BALANCE, shares Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Derivative [Table] Derivative [Table] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Cash Flow Hedge 3 [Member] Cash Flow Hedge 3 [Member] Cash Flow Hedge 3 [Member] Cash Flow Hedge 4 [Member] Cash Flow Hedge 4 [Member] Cash Flow Hedge 4 [Member] Derivative [Line Items] Derivative [Line Items] Hedged Notional Amount Derivative, Notional Amount Contractual INR/USD Foreign Exchange Rate Derivative, Forward Exchange Rate Stockholders' Equity Note [Abstract] Schedule of dividends paid per common share Dividends Declared [Table Text Block] Commitments and Contingencies Disclosure [Abstract] Future minimum payments Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Consolidation, Parent Ownership Interest [Table] Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Table] LPLH [Member] LPL Holdings Inc. [Member] LPL Holdings, Inc. LPL Financial [Member] Lpl Financial Llc [Member] LPL Financial LLC Fortigent [Member] Fortigent [Member] Fortigent Holdings Company, Inc. and its wholly owned subsidiaries Fortigent, LLC, Fortigent Reporting Company, LLC, and Fortigent Strategies Company, LLC. IAG [Member] Independent Advisors Group Corporation [Member] Independent Advisors Group Corporation LPLIA [Member] Lpl Insurance Associate [Member] LPL Insurance Associate. IASG [Member] LPL Independent Advisor Services Group LLC [Member] LPL Independent Advisor Services Group LLC UVEST [Member] Uvest [Member] UVEST. PTCH [Member] Ptc Holdings Inc [Member] PTC Holdings Inc. Consolidation, Parent Ownership Interest [Line Items] Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] Ownership interest percentage in subsidiary Ownership Interest Percentage In Subsidiary Ownership interest percentage in subsidiary. Number of states in which entity operates Number of States in which Entity Operates Concentration Risk Credit Risk Financial Instruments Off Balance Sheet Risk [Abstract] Concentration risk credit risk financial instruments off balance sheet risk. Financial Instruments with Off-Balance-Sheet Credit Risk and Concentrations of Credit Risk Concentration Risk Credit Risk Financial Instruments Off Balance Sheet Risk [Text Block] Description of financial instruments, excluding certain derivatives, with off-balance sheet credit risk (for example, standby letters of credit or financial guarantees), including (1) information about the (shared) activity, region or economic characteristic that identifies the concentration, (2) the face or contract amount of the instrument, (3) the nature and terms of the instrument, including the market risk, cash requirements and accounting policies for it, (4) the maximum amount of loss due to credit risk that would be incurred if the counterparties failed completely to perform according to the terms of the contracts, and any security or collateral that proved to be of no value, (5) the entity's policy of requiring collateral or other security to support financial instruments subject to credit risk, information about access to collateral or other security, and a brief description of the security supporting those financial instruments, and (6) the policy of entering into and a brief description of master netting arrangements to mitigate the credit risk, and the extent to which such arrangements would reduce the maximum amount of loss due to credit risk. Related Party Transactions Related Party Transactions Disclosure [Text Block] Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table] Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table] Exercise Price Range [Axis] Exercise Price Range [Axis] Exercise Price Range [Domain] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] $18.04 - $23.02 Range Two [Member] Range Two. $23.41 - $30.00 Range Three [Member] Range Three. $31.60 - $32.33 Range Four [Member] Range Four. $34.01 - $39.60 Range Five [Member] Range Five. $42.60 - $54.81 Range Six [Member] Range Six. Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] Summary of information about outstanding stock options and warrants Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, End of Period [Abstract] Total Number of Shares, Outstanding Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options Weighted-Average Remaining Life, Outstanding Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term Weighted-Average Exercise Price, Outstanding Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price Number of Shares, Exercisable Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options Weighted-Average Exercise Price, Exercisable Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price Summary of accounts payable and accrued liabilities Accounts Payable and Accrued Liabilities [Abstract] Advisor deferred compensation plan liability Deferred Compensation Arrangement with Individual, Recorded Liability Accrued payroll Accrued Salaries Deferred rent Deferred Rent Credit Accounts payable Accounts Payable Other accrued liabilities Other Accrued Liabilities Total accounts payable and accrued liabilities Accounts Payable and Accrued Liabilities Statement of Comprehensive Income [Abstract] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Net income Other comprehensive income, net of tax: Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax [Abstract] Unrealized gain on cash flow hedges, net of tax expense of $95, $132, and $722 for the years ended December 31, 2016, 2015, and 2014, respectively Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Reclassification adjustment for realized gain on cash flow hedges included in professional services in the consolidated statements of income, net of tax expense (benefit) of $252, $353, and $198 for the years ended December 31, 2016, 2015, and 2014, respectively Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Total other comprehensive income, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Total comprehensive income Schedule of non-deliverable foreign currency contracts Schedule of Derivative Instruments [Table Text Block] Forgivable Loans Amortization Period, Minimum Forgivable Loans Amortization Period, Minimum The minimum period which an advisor's forgivable loan is amortized over on a straight-line basis. Restructuring and Related Activities [Abstract] Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Restructuring Plan [Axis] Restructuring Plan [Axis] Restructuring Plan [Domain] Restructuring Plan [Domain] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Domain] Other Comprehensive Income Location [Domain] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Summary of changes in accrued restructuring expense balance Restructuring and Related Costs [Table Text Block] Due to and from Broker-Dealers and Clearing Organizations [Abstract] Receivables from Product Sponsors, Broker-Dealers and Clearing Organizations and Payables to Broker-Dealers and Clearing Organizations Due to and from Broker-Dealers and Clearing Organizations Disclosure [Text Block] Net income Basic weighted average number of shares outstanding Weighted Average Number of Shares Outstanding, Basic Dilutive common share equivalents Weighted Average Number Diluted Shares Outstanding Adjustment Diluted weighted average number of shares outstanding Weighted Average Number of Shares Outstanding, Diluted Basic earnings per share Earnings Per Share, Basic Diluted earnings per share Earnings Per Share, Diluted Dividend paid per share of common stock Common Stock, Dividends, Per Share, Cash Paid Dividends Dividends Total cash dividends paid during the quarter Debt Disclosure [Abstract] Debt Instruments [Abstract] Debt Instruments [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility [Member] Revolving Credit Facility [Member] Secured Debt [Member] Secured Debt [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Revolving Credit Facility Swingline Loan [Member] Revolving Credit Facility Swingline Loan [Member] Revolving Credit Facility Swingline Loan [Member] Term Loan A [Member] Term Loan A [Member] Term Loan A of Credit Agreement entered into on March 29, 2012 [Member] Amended Term Loan B [Member] Amended Term Loan B [Member] Amended Term Loan B of Credit Agreement entered into on May 13, 2013 [Member] Extended Term Loan B [Member] Extended Term Loan B [Member] Extended Term Loan B of Credit Agreement entered into on November 20, 2015 [Member] New Term Loan B [Member] New Term Loan B [Member] New Term Loan B of Credit Agreement entered into on November 20, 2015 [Member] Interest Base Rate By Type [Axis] Interest Base Rate By Type [Axis] Interest base rate by type. Interest Base Rate By Type [Domain] Interest Base Rate By Type [Domain] Interest base rate by type. Base Rate [Member] Base Rate [Member] London Interbank Offered Rate (LIBOR) [Member] London Interbank Offered Rate (LIBOR) [Member] Alternative Base Rate [Member] Alternative Base Rate [Member] Alternative Base Rate Debt Instrument [Line Items] Debt Instrument [Line Items] Debt Instrument, Basis Spread on Variable Rate Debt Instrument, Basis Spread on Variable Rate Benchmark Short-Term Interest Rate Benchmark Short-Term Interest Rate Benchmark Short-Term Interest Rate Long-term Debt, Current and Noncurrent [Abstract] Long-term Debt, Current and Noncurrent [Abstract] Balance Long-term Debt Interest Rate Debt Instrument, Interest Rate, Effective Percentage Deferred Finance Costs, Net Debt Issuance Costs, Net Cash Flow Hedge 1 [Member] Cash Flow Hedge 1 [Member] Cash Flow Hedge 1 [Member] Number of cash flow hedges entered into by the Company Number of cash flow hedges entered into by the Company The number of non-deliverable foreign currency contracts, which have been designated as cash flow hedges, entered into by the Company. Cash received on settlement of Cash Flow Hedge 1 Derivative, Cash Received on Hedge Share-based Arrangements with Employees and Nonemployees [Abstract] Share-based Arrangements with Employees and Nonemployees [Abstract] Award Recipient [Axis] Award Recipient [Axis] Award Recipient [Axis] Award Recipient Type [Domain] Award Recipient Type [Domain] [Domain] for Award Recipient Type [Axis] Employees, officers, and directors [Member] Employees, officers, and directors [Member] Employees, officers, and directors [Member] Advisors and Financial Institutions [Member] Advisors and Financial Institutions [Member] Advisors and financial institutions. Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Expected life (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Expected stock price volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Expected dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Fair value of options Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Tax expense (benefit) on adjustment for items reclassified to earnings Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Assets [Member] Other Assets [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Fair value of cash flow hedges Foreign Currency Cash Flow Hedge Derivative at Fair Value, Net Line of Credit [Member] Line of Credit [Member] Debt Instrument, Face Amount Debt Instrument, Face Amount Letters of credit, amount outstanding Letters of Credit Outstanding, Amount Applicable interest rate margin Number Of Uncommitted Lines Of Credit Number Of Uncommitted Lines Of Credit Number of uncommitted lines of credit mainted by the Company. Uncommitted lines of credit, unspecified limit Uncommitted lines of credit, unspecified limit The number of uncommitted lines of credit with an unspecified limit maintained by the Company. Line of credit, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Average Outstanding Amount Line of Credit Facility, Average Outstanding Amount Uncommitted lines of credit, utilized Uncommitted lines of credit, utilized Uncommitted lines of credit, utilized Debt Instrument, Interest Rate During Period Debt Instrument, Interest Rate During Period Summary of provision for income taxes Income Tax Expense (Benefit), Continuing Operations [Abstract] Current provision: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) State Current State and Local Tax Expense (Benefit) Total current provision Current Income Tax Expense (Benefit) Deferred benefit: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) State Deferred State and Local Income Tax Expense (Benefit) Total deferred benefit Deferred Income Tax Expense (Benefit) Provision for income taxes Income Tax Expense (Benefit) Summary of accounts payable and accrued liabilities Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2016 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2017 Operating Leases, Future Minimum Payments, Due in Two Years 2018 Operating Leases, Future Minimum Payments, Due in Three Years 2019 Operating Leases, Future Minimum Payments, Due in Four Years 2020 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total Operating Leases, Future Minimum Payments Due ASSETS Assets [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Cash and securities segregated under federal and other regulations Cash and Securities Segregated under Federal and Other Regulations Restricted Cash Restricted Cash and Cash Equivalents Receivables from: Clients, net Receivables from Customers Product sponsors, broker-dealers and clearing organizations Receivables from Brokers-Dealers and Clearing Organizations Advisor loans, net Loans Receivable, Net Others, net Other Receivables, Net, Current Securities owned: Marketable Securities [Abstract] Trading — at fair value Trading Securities Held-to-maturity Held-to-maturity Securities Securities borrowed Securities Borrowed Income taxes receivable Income Taxes Receivable Fixed assets, net Property, Plant and Equipment, Net Goodwill Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Other assets Other Assets Total assets Assets LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] LIABILITIES: Liabilities [Abstract] Drafts payable Drafts Payable Payables to clients Payables to Customers Payables to broker-dealers and clearing organizations Payables to Broker-Dealers and Clearing Organizations Accrued commission and advisory expenses payable Accrued Commissions And Advisory Fees Payable Balance of accrued commissions, recruiting bonus accruals, and other commissions payable. Accounts payable and accrued liabilities Income taxes payable Taxes Payable Unearned revenue Deferred Revenue, Current Securities sold, but not yet purchased — at fair value Financial Instruments Sold, Not yet Purchased, at Fair Value Senior secured credit facilities, net Deferred income taxes, net Deferred Income Tax Liabilities, Net Total liabilities Liabilities STOCKHOLDERS' EQUITY: Stockholders' Equity Attributable to Parent [Abstract] Common stock, $0.001 par value; 600,000,000 shares authorized; 119,917,854 shares and 119,572,352 shares issued at December 31, 2016 and 2015, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Treasury stock, at cost — 30,621,270 shares and 30,048,027 shares at December 31, 2016 and 2015, respectively Treasury Stock, Value Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Retained earnings Retained Earnings (Accumulated Deficit) Total stockholders' equity Total liabilities and stockholders' equity Liabilities and Equity Restricted Stock [Member] Restricted Stock Awards [Member] Restricted stock awards [Member] Share awards for directors that an entity has not yet issued because the agreed-upon consideration, such as employee services, has not yet been received. Restricted Stock Units [Member] Restricted Stock Units (RSUs) [Member] Allocated Share-based Compensation Expense Allocated Share-based Compensation Expense Summary of the status of the Company's restricted stock awards Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Number of Shares, Beginning Balance Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Number of Shares, Granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Number of Shares, Vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Number of Shares, Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Number of Shares, Ending Balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Weighted-Average Grant-Date Fair Value, Beginning Balance Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Weighted-Average Grant-Date Fair Value, Granted 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 Grant-Date Fair Value, Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Weighted-Average Grant-Date Fair Value, Ending Balance Weighted-Average Grant-Date Fair Value, Vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Number of Shares Outstanding, Beginning Balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Number of Shares, Granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Number of Shares, Exercised Number of Shares, Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Number of Shares Outstanding, Ending Balance Number of Shares, Exercisable, Ending Balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Weighted-Average Exercise Price, Outstanding, Beginning Balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Weighted-Average Exercise Price, Granted Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Weighted-Average Exercise Price, Exercised Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Weighted-Average Exercise Price, Forfeited Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Weighted-Average Exercise Price, Outstanding, Ending Balance Weighted-Average Exercise Price, Exercisable, Ending Balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted-Average Exercise Price, Exercisable and expected to vest (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Exercise Price Weighted-Average Remaining Contractual Term for Options Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Weighted-Average Remaining Contractual Term for Options Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Aggregate Intrinsic Value, Outstanding, Ending Balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Aggregate Intrinsic Value, Exercisable, Ending Balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value Net Capital and Regulatory Requirements Brokers and Dealers Disclosure [Text Block] Weighted-average assumptions used for calculating the fair value of its stock options and warrants with the Black-Scholes valuation model Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Summary of the Company's activity in its stock option and warrant plans Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Summary of information about outstanding stock options and warrants Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block] Summary of the status of the Company's restricted stock Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Increase to additional paid-in capital Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation Unrecognized tax benefits, net of the federal benefit on state issues, favorable income tax rate effect Unrecognized Tax Benefits that Would Impact Effective Tax Rate Unrecognized tax benefits, interest accrued Unrecognized Tax Benefits, Interest on Income Taxes Accrued Unrecognized tax benefits, penalties accrued Unrecognized Tax Benefits, Income Tax Penalties Accrued Reduction in unrecognized tax benefits related to the statute of limitations Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit Statement of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Noncash items: Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation Amortization of Intangible Assets Amortization of debt issuance costs Amortization of Debt Issuance Costs Share-based compensation Share-based Compensation Excess tax benefits related to share-based compensation Excess Tax Benefit from Share-based Compensation, Operating Activities Deferred income taxes Loss on extinguishment of debt Write off of Deferred Debt Issuance Cost Loan forgiveness Loan Forgiveness Forgiven portion of previously issued loans to certain shareholders, net of interest incurred. Other Other Noncash Income (Expense) Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Cash and securities segregated under federal and other regulations Increase (Decrease) in Restricted Cash and Investments for Operating Activities Increase in Restricted Cash Operating Activities Increase in Restricted Cash Operating Activities Amount of cash outflow associated with funds that are not available for withdrawal or use (such as held in escrow) and are associated with underlying transactions that are classified as operating activities. Increase (Decrease) in Restricted Cash for Operating Activities Increase (Decrease) in Restricted Cash for Operating Activities Decrease in Restricted Cash Operating Activities Decrease in Restricted Cash Operating Activities Amount of cash inflow associated with funds that are not available for withdrawal or use (such as held in escrow) and are associated with underlying transactions that are classified as operating activities. Receivables from clients Increase Decrease Receivables From Clients The net change during the reporting period in receivables from brokerage clients. Brokerage client balances include margin loans to clients stated, net of allowance for doubtful accounts. Receivables from product sponsors, broker-dealers and clearing organizations Increase (Decrease) in Receivables from Brokers-Dealers and Clearing Organizations Advisor Loans Increase (Decrease) in Other Loans Receivables from others Increase (Decrease) in Other Receivables Securities owned Increase (Decrease) in Trading Securities Securities borrowed Increase (Decrease) in Securities Borrowed Other assets Increase (Decrease) in Other Operating Assets Drafts payable Drafts Payable Changes In Operating Assets And Liabilities The net change during the reporting period in the amounts due on drafts payable during the reporting period. Payables to clients Increase Decrease Payables To Clients The net change during the reporting period in payables to clients, includes amounts payable on cash and margin transactions, including interest on certain client balances. Payables to broker-dealers and clearing organizations Increase (Decrease) in Payables to Broker-Dealers and Clearing Organizations Accrued commissions and advisory expenses payable Changes In Accrued Commissions And Advisory Fees Payable The net change in the balance of accrued commissions, recruiting bonus accruals, and other commissions payable over the reporting period. Accounts payable and accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Income taxes receivable/payable Increase (Decrease) in Income Taxes Unearned revenue Increase (Decrease) in Deferred Revenue Securities sold, but not yet purchased Increase (Decrease) in Financial Instruments Sold, Not yet Purchased 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 [Abstract] Capital expenditures Payments to Acquire Property, Plant, and Equipment Purchase of goodwill and other intangible assets Payments to Acquire Business Two, Net of Cash Acquired Proceeds from disposal of fixed assets Proceeds from Sale of Productive Assets Purchase of securities classified as held-to-maturity Payments to Acquire Held-to-maturity Securities Proceeds from maturity of securities classified as held-to-maturity Proceeds from Sale and Maturity of Held-to-maturity Securities Deposits of restricted cash Increase in Restricted Cash Release of restricted cash Decrease in Restricted Cash Proceeds from sale of equity investment Proceeds from Sale of Other Investments Purchases of minority interest investments Payments to Acquire Additional Interest in Subsidiaries Net cash 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 [Abstract] Proceeds from revolving credit facility Proceeds from Lines of Credit Repayments of revolving credit facility Repayments of Lines of Credit Repayment of senior secured term loans Repayments of Long-term Lines of Credit Proceeds from senior secured term loans Proceeds from Long-term Lines of Credit Payment of debt issuance costs Payments of Debt Issuance Costs Payment of contingent consideration Proceeds from (Payments for) Other Financing Activities Tax payments related to settlement of restricted stock units Payments Related to Tax Withholding for Share-based Compensation Repurchase of common stock Payments for Repurchase of Common Stock Dividends on common stock Payments of Dividends Excess tax benefits related to share-based compensation Excess Tax Benefit from Share-based Compensation, Financing Activities Proceeds from stock option exercises and other Proceeds from Stock Options Exercised Payment of Leasehold Financing Obligation Payment of Leasehold Financing Obligation Payment of Leasehold Financing Obligation Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS Cash and Cash Equivalents, Period Increase (Decrease) CASH AND CASH EQUIVALENTS - Beginning of year CASH AND CASH EQUIVALENTS - End of year SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION: Supplemental Cash Flow Information [Abstract] Interest paid Interest Paid Income taxes paid Income Taxes Paid NONCASH DISCLOSURES: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Capital expenditures included in accounts payable and accrued liabilities Capital Expenditures Incurred but Not yet Paid Fixed assets acquired under built-to-suit lease Fixed assets acquired under built-to-suit lease Fixed assets resulting from a built-to-suit lease. Finance Obligation related to real estate projects non cash finance obligation The increase during the period in finance obligations related to real estate projects that results in no cash inflows or outflows during the period in which they occur. Discount on proceeds from senior secured credit facilities recorded as debt issuance costs Discount On Proceeds From Senior Credit Facilities Recorded As Debt Issuance Costs Discount on proceeds from senior credit facilities recorded as debt issuance costs Amount reclassified to Other expenses Prior Period Reclassification Adjustment Employee and Advisor Benefit Plans [Abstract] Employee and Advisor Benefit Plans (Textuals) [Abstract] Employee and Advisor Benefit Plans. Percentage of eligible compensation matched by employer Defined Contribution Plan, Employer Matching Contribution, Percent of Match Percentage of employee compensation eligible for match Defined Contribution Plan, Employee Compensation Eligible for Match, Percent Defined Contribution Plan, Employee Compensation Eligible for Match, Percent Total contribution cost recognized Defined Contribution Plan, Cost Recognized Employee stock purchase plan purchase price discount Employee Stock Purchase Plan Purchase Price Discount Discount percentage on purchase price per share of common stock at market value of the shares at the lower of the grant date price (first day of the offering period) and the purchase date price (last day of the offering period). Deferred Compensation Arrangements [Abstract] Deferred Compensation Arrangements [Abstract] Deferred Compensation Arrangement with Individual, Recorded Liability Deferred Compensation Arrangement with Individual, Employer Contribution Deferred Compensation Arrangement with Individual, Employer Contribution Deferred Compensation Arrangement with Individual, Compensation Expense Deferred Compensation Arrangement, Rabbi Trust, Employer Contribution The amount of payment into the fund established for purposes of making future disbursements to the individuals in accordance with the terms and understanding of the deferred compensation arrangement. Deferred Compensation Arrangement, Rabbi Trust, Recorded Liability Deferred Compensation Arrangement, Rabbi Trust, Recorded Liability The carrying amount of the liability as of the balance sheet date to individuals under a deferred compensation arrangement. This amount may be the result of periodic accruals made over the period of active employment, or reflect termination benefits resulting contractual terms or a death benefit. Depreciation and amortization expense Depreciation, Depletion and Amortization Interest expense from operations (did not exceed) Other Cost and Expense, Operating Leases [Abstract] Portion of design and construction costs company is obligated to pay Portion of Design and Construction Costs Company is Obligated to Pay Portion of Design and Construction Costs Company is Obligated to Pay Expected design and construction costs for South Carolina Other Commitment Future South Carolina office space lease term Lessee Leasing Arrangements, Operating Leases, Term of Contract Leases, Operating [Abstract] Leases, Operating [Abstract] Rent expense for operating leases Operating Leases, Rent Expense, Net Future minimum sublease rental income Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals Income Taxes Income Tax Disclosure [Text Block] Advisors and Financial Institutions [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Stock options and warrants [Member] Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Share-based Compensation [Abstract] Share-based Compensation [Abstract] Authorized shares Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Authorized unissued shares Share Based Compensation Arrangement By Share Based Payment Award Shares Reserved Share based compensation arrangement by share based payment award shares reserved. Share based compensation expense Share based compensation cost unrecognized Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Non-vested compensation cost weighted-average period Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Summary of company's effective income tax rate reconciliation Effective Income Tax Rate Reconciliation, Percent [Abstract] Federal statutory income tax rates 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 Non-deductible expenses Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent Share-based compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Percent Business energy tax credit Effective Income Tax Rate Reconciliation, Tax Credit, Percent Goodwill derecognition Effective Income Tax Rate Reconciliation, Nondeductible Expense, Goodwill Derecognition, Percent Effective Income Tax Rate Reconciliation, Nondeductible Expense, Goodwill Derecognition, Percent Contingent consideration obligations Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Percent Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Percent Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Percent Effective Income Tax Rate Reconciliation, Tax Credit, Research, Percent Effective Income Tax Rate Reconciliation, Tax Credit, Research, Percent Other Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Effective income tax rates Effective Income Tax Rate Reconciliation, Percent Schedule of Held-to-maturity Securities [Table] Schedule of Held-to-maturity Securities [Table] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Debt Security [Axis] Debt Security [Axis] Major Types of Debt Securities [Domain] Major Types of Debt Securities [Domain] U.S. Treasury Securities [Member] US Treasury Securities [Member] Schedule of Held-to-maturity Securities [Line Items] Schedule of Held-to-maturity Securities [Line Items] Maturities of securities held-to-maturity Held-to-maturity Securities, Debt Maturities [Abstract] U.S. government notes - at amortized cost, Within one year Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount U.S. government notes - at amortized cost, After one but within five years Held-to-maturity Securities, Debt Maturities, after One Through Five Years, Net Carrying Amount U.S. government notes - at amortized cost, After five but within ten years Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount U.S. government notes - at amortized cost, Total U.S. government notes - at fair value, Within one year Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value U.S. government notes - at fair value, After one but within five years Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value U.S. government notes - at fair value, After five but within ten years Held-to-maturity Securities, Debt Maturities, Year Six Through Ten, Fair Value U.S. government notes - at fair value, Total Held-to-maturity Securities, Fair Value Fair Value Measurements Fair Value Disclosures [Text Block] Restructuring Charges [Member] Restructuring Charges [Member] Outsourcing and other related costs Outsourcing and Other Related Costs [Member] Outsourcing and Other Related Costs [Member] Technology transformation costs Technology Transformation Costs [Member] Technology Transformation Costs [Member] Employee severance obligations and other related costs Employee Severance [Member] Asset impairments Tangible Asset Impairment Charges [Member] Tangible Asset Impairment Charges [Member] Employee Relocation [Member] Employee Relocation [Member] Facility Closing [Member] Facility Closing [Member] Asset Impairment Charges [Member] Asset Impairment Charges [Member] Asset Impairment Charges [Member] Restructuring Reserve [Roll Forward] Restructuring Reserve [Roll Forward] Accrued Balance, Beginning of Period Restructuring Reserve Costs incurred Restructuring and Related Cost, Incurred Cost Payments Payments for Restructuring Restructuring Reserve, Settled without Cash Restructuring Reserve, Settled without Cash Accrued Balance, End of Period Cumulative Costs Incurred to Date Restructuring and Related Cost, Cost Incurred to Date Net Capital Net Capital Alternative Net Capital Requirement Alternative Net Capital Requirement Minimum Net Capital Required for Broker-Dealer Subsidiary Minimum Net Capital Required for Broker-Dealer Subsidiary 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] Internally developed software [Member] Software Development [Member] Computers and software [Member] Other Capitalized Property Plant and Equipment [Member] Furniture and equipment [Member] Furniture and Fixtures [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Impairment of Intangible Assets (Excluding Goodwill) Impairment of Intangible Assets (Excluding Goodwill) Other Cost and Expense, Operating Fixed assets useful life (in years) Property, Plant and Equipment, Useful Life Impairment charge for certain fixed assets Tangible Asset Impairment Charges Summary of gross unrecognized tax benefits including interest and penalties reconciliation Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Balance - Beginning of year Unrecognized Tax Benefits Increases for tax positions related to the current year Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Reductions as a result of a lapse of the applicable statute of limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Balance - End of year Schedule of Trading Securities and Other Trading Assets, Major Types of Trading Securities and Assets [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Trading Securities and Assets [Domain] Major Types of Debt and Equity Securities [Domain] Money Market Funds [Member] Money Market Funds [Member] Mutual Funds [Member] Mutual Funds [Member] An investment vehicle that is made up of a pool of funds collected from many investors for the purpose of investing in securities such as stocks, bonds, money market instruments and similar assets. Mutual funds are operated by money managers, who invest the fund's capital and attempt to produce capital gains and income for the fund's investors. Equity Securities [Member] Equity Securities [Member] Debt Securities [Member] Debt Securities [Member] U.S. Treasury Obligations [Member] Certificates of Deposit [Member] Certificates of Deposit [Member] Security Owned and Sold, Not yet Purchased, at Fair Value [Axis] Security Owned and Sold, Not yet Purchased, at Fair Value [Axis] Security Owned and Sold, Not yet Purchased Fair Value, Security Name [Domain] Security Owned and Sold, Not yet Purchased Fair Value, Security Name [Domain] Securities Sold, Not yet Purchased [Member] Securities Sold, Not yet Purchased [Member] Cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Securities owned — trading Other assets Other Assets, Fair Value Disclosure Total assets at fair value Assets, Fair Value Disclosure, Recurring Securities sold, but not yet purchased Accounts payable and accrued liabilities Accounts Payable and Accrued Liabilities, Fair Value Disclosure Total liabilities at fair value Financial and Nonfinancial Liabilities, Fair Value Disclosure Class of Treasury Stock [Table] Class of Treasury Stock [Table] January 2016 [Member] January 2016 [Member] January 2016 [Member] Goldman, Sachs and Co. [Member] Goldman, Sachs and Company [Member] Goldman, Sachs and Company [Member] TPG Capital [Member] Equity, Class of Treasury Stock [Line Items] Equity, Class of Treasury Stock [Line Items] Stock Repurchase Program, Remaining Authorized Repurchase Amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Increased number of shares authorized for the share repurchase program (in shares) Stock Repurchase Program, Authorized Amount Stock Repurchased During Period, Value Accelerated Share Repurchases, Cash or Stock Settlement Number of shares remaining in share repurchase program (in shares) Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased Treasury Stock Acquired, Average Cost Per Share Treasury Stock, Value, Acquired, Cost Method Schedule of Intangible Assets by Major Class [Table] Schedule of Intangible Assets by Major Class [Table] Schedule of Intangible Assets by Major Class [Table] Advisor and financial institution relationships [Member] Advisor And Financial Institution Relationships [Member] Advisor and financial institution relationships. Product sponsor relationships [Member] Product Sponsor Relationships [Member] Product sponsor relationships. Client relationships [Member] Customer Relationships [Member] Trade names [Member] Trade Names [Member] Indefinite-lived Intangible Assets by Major Class [Axis] Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Trademarks and Trade Names [Member] Trademarks and Trade Names [Member] Intangible Assets [Line Items] Intangible Assets [Line Items] Intangible Assets [Line Items] Weighted-Average Life Remaining (in years) Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Total intangible assets Definite-lived intangible assets: Finite-Lived Intangible Assets, Net [Abstract] Gross Carrying Value Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Indefinite-lived intangible assets: Intangible Assets, Net (Excluding Goodwill) [Abstract] Net Carrying Value Indefinite-Lived Intangible Assets (Excluding Goodwill) Securities borrowed, contract value Securities borrowed, collateral market value Securities Borrowed, Fair Value Disclosure Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Receivables: Receivables from Brokers-Dealers and Clearing Organizations [Abstract] Commissions receivable from product sponsors and others Commissions and Floor Brokerage Receivables Receivable from clearing organizations Receivables from Clearing Organizations Receivable from broker-dealers Receivable From Broker Dealers Receivable from broker-dealers. Securities failed-to-deliver Securities Failed-to-Deliver Total receivables Payables: Payables to Broker-Dealers and Clearing Organizations [Abstract] Payable to clearing organizations Payable To Clearing Organizations Payable to clearing organizations. Payable to broker-dealers Payable To Broker Dealers Payable to broker-dealers. Securities failed-to-receive Securities Failed-to-Receive Total payables Restructuring Restructuring and Related Activities Disclosure [Text Block] Summary of amortized cost, gross unrealized loss, and fair value of securities held-to-maturity Held-to-maturity Securities, Classified [Abstract] Gross unrealized loss Held-to-maturity Securities, Accumulated Unrecognized Holding Loss U.S. government notes - at fair value, Total Components of the net deferred tax liabilities Components of Deferred Tax Assets and Liabilities [Abstract] Deferred tax assets: Deferred Tax Assets, Net [Abstract] Accrued liabilities Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Severance Payments Share-based compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost State taxes Deferred Tax Assets, Operating Loss Carryforwards, State and Local Deferred rent Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Deferred Rent Provision for bad debts Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts Net operating losses Deferred Tax Assets, Operating Loss Carryforwards Deferred Tax Assets, Tax Deferred Expense, Forgivable Loans Deferred Tax Assets, Tax Deferred Expense, Forgivable Loans Amount before allocation of valuation allowance of deferred tax asset attributable to deductible temporary differences from forgivable loans Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Self Insurance Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Self Insurance Deferred Tax Assets, Tax Deferred Expenses, Forgivable Loans Deferred Tax Assets, Tax Deferred Expenses, Forgivable Loans Amount before allocation of valuation allowance of deferred tax assets attributable to deductible temporary differences from forgivable loans Other Deferred Tax Assets, Other Total deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Deferred tax liabilities: Deferred Tax Liabilities, Gross [Abstract] Amortization of intangible assets Deferred Tax Liabilities, Intangible Assets Depreciation of fixed assets Deferred Tax Liabilities, Property, Plant and Equipment Other Deferred Tax Liabilities, Other Total deferred tax liabilities Deferred Tax Liabilities, Gross Deferred income taxes, net Deferred Tax Liabilities, Net Earnings per Share Earnings Per Share [Text Block] Antidilutive securities excluded from computation of Earnings per Share amount Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Income Statement [Abstract] REVENUES: Revenues [Abstract] Commission Brokerage Commissions Revenue Advisory Investment Advisory Fees Asset-based Asset Based Fees Revenue recognized in the period for fees from cash sweep programs, sponsorship programs, omnibus processing and networking services. Transaction and fee Transaction And Other Fees Revenue recognized in the period from transaction fees and ticket charges, subscription fees, IRA custodian fees, contract and license fees, conference fees and small or inactive account fees. Interest income, net of interest expense Interest Income (Expense), Net Other Other Income Total net revenues Revenues EXPENSES: Operating Expenses [Abstract] Commission and advisory Commissions And Advisory Fees Gross commissions and advisory fees that are earned and paid out to customers based on the sale of various products and services, production bonuses for achieving production levels, share-based compensation expense for stock options and warrants granted to customers, and deferred commissions for customers as part of a non-qualified deferred compensation plan. Compensation and benefits Labor and Related Expense Promotional Promotional Expenses The total expense recognized in the period for promotional items and business development costs. Depreciation and amortization Professional services Professional Fees Occupancy and equipment Occupancy, Net Brokerage, clearing, and exchange Floor Brokerage, Exchange and Clearance Fees Communications and data processing Communications and Information Technology Restructuring charges Restructuring Charges Other Other Expenses Total operating expenses Operating Expenses Non-operating interest expense Interest Expense, Subordinated Notes and Debentures Loss on extinguishment of debt Gain (Loss) on Extinguishment of Debt INCOME BEFORE PROVISION FOR INCOME TAXES Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest PROVISION FOR INCOME TAXES NET INCOME EARNINGS PER SHARE (NOTE 15) Earnings per share, basic Earnings per share, diluted Weighted-average shares outstanding, basic Weighted-average shares outstanding, diluted Goodwill and Intangible Assets Disclosure [Abstract] Goodwill impairment loss Goodwill, Impairment Loss Impairment of Intangible Assets (Excluding Goodwill) [Abstract] Impairment of Intangible Assets (Excluding Goodwill) [Abstract] Impairment of intangible assets, indefinite-lived (excluding goodwill) Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) Impairment of intangible assets, finite-lived Impairment of Intangible Assets, Finite-lived Finite-lived intangible assets, useful life Finite-Lived Intangible Asset, Useful Life Goodwill and Intangible Asset Impairment Goodwill and Intangible Asset Impairment Quarterly Financial Information Disclosure [Abstract] Net revenues Dividends declared per share Common Stock, Dividends, Per Share, Declared Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Loss Contingencies [Table] Loss Contingencies [Table] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Loss Contingency, Range of Possible Loss, Portion Not Accrued Loss Contingency, Range of Possible Loss, Portion Not Accrued Forgivable Loans Amortization Period, Maximum Forgivable Loans Amortization Period, Maximum The minimum period which an advisor's forgivable loan is amortized over on a straight-line basis. Forgivable Advisor Loans Forgivable Loans Forgivable Loans Receivables from others [Member] Receivables from others [Member] Receivables from others consisting primarily of other accrued fees from product sponsors and advisors [Member] Charge-offs, net of recoveries Allowance for Doubtful Accounts Receivable, Write-offs Selected Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Leasehold improvements [Member] Leasehold Improvements [Member] Building [Member] Building [Member] Land [Member] Land [Member] Construction in Progress [Member] Construction in Progress [Member] Total fixed assets Property, Plant and Equipment, Gross Development in Process Development in Process Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Fixed assets, net Schedule of selected quarterly financial data Quarterly Financial Information [Table Text Block] Debt Debt Disclosure [Text Block] Outstanding borrowings Schedule of Long-term Debt Instruments [Table Text Block] Summary of minimum calendar year payments and maturities of the senior secured borrowings Schedule of Maturities of Long-term Debt [Table Text Block] Financial assets and financial liabilities measured at fair value on a recurring basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] 2016 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2017 Long-term Debt, Maturities, Repayments of Principal in Year Two 2018 Long-term Debt, Maturities, Repayments of Principal in Year Three 2019 Long-term Debt, Maturities, Repayments of Principal in Year Four 2020 Long-term Debt, Maturities, Repayments of Principal in Year Five Thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five Total The components of fixed assets Property, Plant and Equipment [Table Text Block] Schedule for uncollectible amounts due from clients Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Organization and Description of the Company Nature of Operations [Text Block] Receivables from Product Sponsors, Broker-Dealers and Clearing Organizations and Payables to Broker-Dealers and Clearing Organizations Schedule of Due to (from) Broker-Dealers and Clearing Organizations [Table Text Block]