Pension and Other Postretirement Benefit Expense [Abstract] Pension Plans and Postretirement Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] Property, Plant and Equipment [Abstract] 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] Land, buildings and leasehold improvements Land, Buildings and Improvements [Member] Beef processing machinery and equipment Beef Processing Machinery And Equipment [Member] Beef Processing Machinery And Equipment [Member] Other machinery and equipment Machinery and Equipment [Member] Corporate aircraft Air Transportation Equipment [Member] Furniture, fixtures and office equipment Furniture and Fixtures [Member] Construction in progress Construction in Progress [Member] Other Other Capitalized Property Plant and Equipment [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property, equipment and leasehold improvements, gross Property, Plant and Equipment, Gross Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property, equipment and leasehold improvements, net Property, Plant and Equipment, Net Depreciable Lives Property, Plant and Equipment, Useful Life Investments [Abstract] Schedule of Investments [Table] Schedule of Investments [Table] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] U.S. government securities US Treasury and Government [Member] Residential mortgage-backed securities Residential Mortgage Backed Securities [Member] Commercial mortgage-backed securities Commercial Mortgage Backed Securities [Member] Other asset-backed securities Other Asset Backed Securities [Member] Other asset-backed securities. All other corporates Other Corporate Bonds [Member] Bonds and notes Debt Securities [Member] Banks, trusts and insurance companies Common Stock Banks Trusts And Insurance Companies [Member] Common stock Banks, trusts and insurance companies [Member] Industrial, miscellaneous and all other Common Stock Industrial Miscellaneous And All Other [Member] Common stock Industrial, Miscellaneous and All Other [Member] Equity securities Corporate Equity Securities [Member] Corporate Equity Securities [Member] Schedule of Investments [Line Items] Schedule of Investments [Line Items] Amortized Cost Available-for-sale Securities, Amortized Cost Basis Gross Unrealized Gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Estimated Fair Value Available-for-sale Securities Condensed Financial Information of Parent Company Only Disclosure [Abstract] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Parent Company Parent Company [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Prime Rate Prime Rate [Member] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Basis spread on variable rate Equity Method Subsidiaries, Basis Spread on Variable Rate Advances Equity Method Subsidiaries, Basis Spread on Variable Rate Advances Intercompany loans Expected Future Loans, Amount Expected Future Intercompany Loans, Amount Dividends received from subsidiaries Non-Cash Dividends Received From Subsidiaries Non-Cash Dividends Received From Subsidiaries Decrease of investments in subsidiaries Increase (Decrease) Of Investments in Subsidiaries Increase (Decrease) Of Investments in Subsidiaries Decrease of advances to subsidiaries Increase (Decrease) Of Advances To Subsidiaries Increase (Decrease) Of Advances To Subsidiaries Decrease of advances from subsidiaries Increase (Decrease) Of Advances From Subsidiaries Increase (Decrease) Of Advances From Subsidiaries Discontinued Operations and Disposal Groups [Abstract] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] Conwed Conwed [Member] Conwed [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Disposed of by Sale Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Cash Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents Receivables Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net Property, equipment and leasehold improvements, net Disposal Group, Including Discontinued Operation, Property, Plant and Equipment Intangible assets, net and goodwill Disposal Group, Including Discontinued Operation, Intangible Assets, net and Goodwill Disposal Group, Including Discontinued Operation, Intangible Assets, net and Goodwill Inventory Disposal Group, Including Discontinued Operation, Inventory Other assets Disposal Group, Including Discontinued Operation, Other Assets Assets held for sale Disposal Group, Including Discontinued Operation, Assets Statement of Cash Flows [Abstract] Net cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Adjustments to reconcile net income to net cash provided by (used for) operations: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Deferred income tax provision Deferred Income Tax Expense (Benefit), Including Discontinued Operations Deferred Income Tax Expense (Benefit), Including Discontinued Operations Depreciation and amortization of property, equipment and leasehold improvements Depreciation and amortization of property equipment and leasehold improvements Depreciation and amortization of property, equipment and leasehold improvements. Other amortization Other Depreciation and Amortization Share-based compensation Share-based Compensation Provision for doubtful accounts Provision for Doubtful Accounts Including Amounts Classified in Cost of Goods Sold Provision for Doubtful Accounts Including Amounts Classified in Cost of Goods Sold Net securities gains Gain (Loss) on Investments Income related to associated companies Income (Losses) Related to Associated Companies Including Income (Losses) Related to Subsidiary Associated Companies Primarily Classified as Revenues Income (Losses) Related to Associated Companies Including Income (Losses) Related to Subsidiary Associated Companies Primarily Classified as Revenues Distributions from associated companies Dividends Or Distributions From Associated Companies Dividends Or Distributions From Associated Companies Net losses related to property and equipment, and other assets Net gains losses related to real estate property and equipment and other assets Net (gains) losses related to real estate, property and equipment, and other assets. Gain on sale of subsidiaries Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Gain on disposal of discontinued operations Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax Change in estimated litigation reserve Loss Contingency Accrual, Period Increase (Decrease) Net change in: Increase (Decrease) in Operating Capital [Abstract] Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations Increase (Decrease) in Cash and Securities Segregated and on Deposit for Regulatory Purposes or Deposited with Clearing and Depository Organizations Increase Decrease in Cash and Securities Segregated and on Deposit for Regulatory Purposes or Deposited with Clearing and Depository Organizations Trading assets Increase (Decrease) in Trading Securities Investments in managed funds Increase (Decrease) In Investments in Managed Funds Increase (Decrease) In Investments in Managed Funds Securities borrowed Increase (Decrease) in Securities Borrowed Securities purchased under agreements to resell Increase (Decrease) in Securities Purchased Under Agreements to Resell Increase (Decrease) in Securities Purchased Under Agreements to Resell Receivables from brokers, dealers and clearing organizations Increase (Decrease) in Receivables from Brokers-Dealers and Clearing Organizations Receivables from customers of securities operations Increase (Decrease) Receivables from Customers of Securities Operations Increase (Decrease) Receivables from Customers of Securities Operations Other receivables Increase (Decrease) in Other Receivables Other assets Increase (Decrease) In Other Assets Increase Decrease In Other Assets Trading liabilities Increase (Decrease) in Trading Liabilities Securities loaned Increase (Decrease) in Securities Loaned Transactions Securities sold under agreements to repurchase Increase (Decrease) in Payables under Repurchase Agreements Payables to brokers, dealers and clearing organizations Increase (Decrease) in Payables to Broker-Dealers and Clearing Organizations Payables to customers of securities operations Increase (Decrease) in Payables to Customers Trade payables, expense accruals and other liabilities Increase (Decrease) in Trade Payables Expense Accruals and Other Liabilities Increase (Decrease) in Trade Payables Expense Accruals and Other Liabilities Other Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash provided by (used for) operating activities Net Cash Provided by (Used in) Operating Activities Net cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Acquisitions of property, equipment and leasehold improvements, and other assets Payments to Acquire Property, Plant, and Equipment, and Other Assets Payments to Acquire Property, Plant, and Equipment, and Other Assets Proceeds from disposals of property and equipment, and other assets Proceeds from disposals of property and equipment, and other assets Proceeds from disposals of property and equipment, and other assets. Proceeds from sale of subsidiary, net of expenses and cash of operations sold Proceeds From Sale Of Subsidiary, Net Of Expenses And Cash Of Operations Sold Proceeds From Sale Of Subsidiary, Net Of Expenses And Cash Of Operations Sold Proceeds from disposal of discontinued operations, net of expenses and cash of operations sold Proceeds From (Payments Related To) Disposal Of Discontinued Operations, Net Of Expenses And Cash Of Operations Sold Proceeds From (Payments Related To) Disposal Of Discontinued Operations, Net Of Expenses And Cash Of Operations Sold Acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Advances on notes, loans and other receivables Payments to Acquire Receivables Collections on notes, loans and other receivables Proceeds from Sale and Collection of Receivables Loans to and investments in associated companies Payments to Acquire Interest in Subsidiaries and Affiliates Capital distributions and loan repayment from associated companies Capital distributions and loan repayment from associated companies Capital distributions and loan repayment from associated companies. Proceeds from sale of associated companies Proceeds from Sale of Equity Method Investments Deconsolidation of subsidiary entities Cash of subsidiary entities deconsolidated Cash of subsidiary entities deconsolidated Purchases of investments (other than short-term) Purchases of investments other than short term Purchases of investments (other than short-term). Proceeds from maturities of investments Proceeds from maturities of investments Proceeds from maturities of investments. Proceeds from sales of investments Proceeds from sales of investments Proceeds from sales of investments. Other Payments for (Proceeds from) Other Investing Activities Net cash provided by (used for) investing activities Net Cash Provided by (Used in) Investing Activities Net cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Issuance of debt, net of issuance costs Proceeds from Other Debt Other changes in short-term borrowings, net Proceeds from (Repayments of) Short-term Debt Repayment of debt Repayments of Other Debt Net change in other secured financings Proceeds from other secured financings, Net Proceeds from other secured financings, net. Net change in bank overdrafts Proceeds from (Repayments of) Bank Overdrafts Issuance of common shares Proceeds from Issuance of Common Stock Net contributions from (distributions to) redeemable noncontrolling interests Net Contributions from Distributions to Redeemable Noncontrolling Interests Net Contributions from Distributions to Redeemable Noncontrolling Interests Distributions to noncontrolling interests Payments to Noncontrolling Interests Contributions from noncontrolling interests Proceeds from Noncontrolling Interests Purchase of common shares for treasury Payments for Repurchase of Common Stock Dividends paid Payments of Ordinary Dividends, Common Stock Other Proceeds from (Payments for) Other Financing Activities Net cash provided by (used for) financing activities Net Cash Provided by (Used in) Financing Activities Effect of foreign exchange rate changes on cash Effect of Exchange Rate on Cash and Cash Equivalents Change in cash classified as assets held for sale Change in Cash Classified as Assets Held for Sale Change in Cash Classified as Assets Held for Sale Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at January 1, Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at December 31, Share-based Compensation [Abstract] Compensation Plans Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Directors' Plan Directors Plan [Member] Directors Plan [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Value of shares to be granted to each non employee director Share Based Compensation Arrangement By Directors Stock Compensation Plan Value Of Shares For Each Director Value of annual grant to each non-employee director of restricted stock or deferred shares. Vesting period for award granted Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Shares issuable upon settlement of deferred shares Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Issuable upon Settlement of Deferred Shares Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Issuable upon Settlement of Deferred Shares Stock available for grant Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Accounting Developments Accounting Developments [Text Block] Disclosure of the adoption of new accounting pronouncements that may impact the entity's financial reporting. Derivative Instruments and Hedging Activities Disclosure [Abstract] A- or higher Fair Value Of OTC Derivatives Assets, Counterparty Credit Quality Fair value of OTC derivatives assets, counterparty credit quality A- or higher. BBB- to BBB Fair value of OTC derivatives assets, counterparty credit quality BBB minus to BBB plus Fair value of OTC derivatives assets, counterparty credit quality BBB- to BBB+. BB or lower Fair value of OTC derivatives assets, counterparty credit quality BB plus or lower Fair value of OTC derivatives assets, counterparty credit quality BB or lower. Unrated Fair Value Of Over Counter Derivatives Assets Counterparty Credit Quality Unrated Fair value of OTC derivatives assets, counterparty credit quality unrated. Total Otc Derivative Assets Included In Financial Instruments Owned OTC Derivative Assets Included In Financial Instruments Owned. 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 gains on available for sale securities Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member] Net unrealized foreign exchange losses Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member] Net unrealized losses in instrument specific credit risk Accumulated Net Gain (loss) on Instrument Specific Credit Risk Including Portion Attributable to Noncontrolling Interest [Member] Accumulated Net Gain (loss) on Instrument Specific Credit Risk Including Portion Attributable to Noncontrolling Interest [Member] Net unrealized losses on cash flow hedges Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] Net minimum pension liability Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member] AOCI attributable to Parent AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated other comprehensive income Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Variable Interest Entity, Measure of Activity [Abstract] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Eliminations Consolidation, Eliminations [Member] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Securitization Vehicles Securitization Vehicles [Member] Securitization Vehicles [Member] Real Estate Investment Vehicles Real Estate Investment Vehicles [Member] Real Estate Investment Vehicles [Member] Jefferies Jefferies Group Inc [Member] Jefferies Group Inc Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Cash Financial instruments owned Financial Instruments, Owned, at Fair Value Securities purchased under agreement to resell Securities Purchased under Agreements to Resell Receivables Receivables Receivables Loans to and investments in associated companies Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Other Other Assets Total assets Assets Other secured financings Other Secured Financings Long-term debt Long-term Debt Other Other Liabilities Total liabilities Liabilities Noncontrolling interests Stockholders' Equity Attributable to Noncontrolling Interest Secured financings eliminated in consolidation Secured financings eliminated in consolidation Secured financings eliminated in consolidation Intercompany Payables Intercompany Payables Intercompany Payables Commitments and Contingencies Disclosure [Abstract] Loss Contingencies [Table] Loss Contingencies [Table] Empire Insurance Company Empire Insurance Company [Member] Empire Insurance Company [Member] National Beef National Beef [Member] National Beef [Member] 54 Madison 54 Madison Capital, LLC [Member] 54 Madison Capital, LLC [Member] Jefferies Finance Jefferies Finance Llc [Member] Jefferies Finance, LLC [Member] Folger Hill Folger Hill Asset Management Llc [Member] Folger Hill Asset Management LLC [Member] Jefferies Plan Jefferies Group LLC [Member] Jefferies Group LLC Berkadia Berkadia [Member] Berkadia [Member] Other subsidiaries Other Subisidiaries [Member] Other Subisidiaries [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Jefferies Capital Partners LLC and Its Private Equity Funds Jefferies Capital Partners Llc And Private Equity Funds [Member] Jefferies Capital Partners LLC and Private Equity Funds [Member] Other Various Investments Other Various Investments [Member] Other Various Investments [Member] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Standby letters of credit Financial Standby Letter of Credit [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Noncancellable operating lease terms Noncancellable Operating Lease Terms Noncancellable Operating Lease Terms Rental expense (net of sublease rental income) Operating Leases, Rent Expense, Net Service charge commitment for city improvements Service Charge Commitment For City Improvements Service Charge Commitment For City Improvements Service charge commitment for city improvements, duration of payments Service Charge Commitment For City Improvements, Duration Of Payments Service Charge Commitment For City Improvements, Duration Of Payments Service charge commitment for city improvements, remaining amount Service Charge Commitment For City Improvements, Remaining Amount Service Charge Commitment For City Improvements, Remaining Amount Service charge commitment for city improvements future payment in 2018 Service Charge Purchase Commitment Estimated Future Payment Year One Service Charge Purchase Commitment Estimated Future Payment Year One Service charge commitment for city improvements future payment in 2019 Service Charge Purchase Commitment Estimated Future Payment Year Two Service Charge Purchase Commitment Estimated Future Payment Year Two Service charge commitment for city improvements future payment in subsequent years Service Charge Commitments For City Improvements Remaining Balance To Be Paid In Subsequent Years Service Charge Commitments For City Improvements Remaining Balance To Be Paid In Subsequent Years Maximum amount committed to invest as per agreement Maximum Amount Committed to Invest as Per Agreement Maximum Amount Committed to Invest as Per Agreement. Amount of contributed commitment Amount of Contributed Commitment Amount of Contributed Commitment Approved unfunded commitment Approved Unfunded Commitment Approved Unfunded Commitment Equity commitments Equity Commitments Committed equity capitalization. Loan commitments outstanding to clients Outstanding Loan Commitments to Clients Outstanding Loan Commitments to Clients. Line of credit commitment to associated companies, funded portion Line of credit commitment to associated companies, funded portion. Line of credit commitment to associated companies, funded portion. Line of credit facility commitment of Jefferies Line of Credit Facility, Commitment Under Joint Venture, Entity Portion Line of Credit Facility, Commitment Under Joint Venture, Entity Portion Entity line of credit facility, Original Term Entity line of credit facility, Original Term Entity line of credit facility, Original Term Entity line of credit facility Entity line of credit facility Entity line of credit facility. Number of days prior written notice for optional termination right Entity Line Of Credit Facility, Number Of Days Prior Written Notice For Optional Termination Right Entity Line Of Credit Facility, Number Of Days Prior Written Notice For Optional Termination Right Amount funded under credit facility Funded revolving credit facility Funded revolving credit facility. Fair value of derivative contracts meeting the definition of a guarantee Derivative Contracts Meeting Definition of A Guarantee Derivative Contracts Meeting Definition of A Guarantee Fair value of mortgage-related and other purchase commitments Fair value of mortgage-related and other purchase commitments Fair value of mortgage-related and other purchase commitments Reimbursement of losses incurred, maximum percentage Reimbursement Of Losses Incurred, Maximum Percentage Reimbursement of losses incurred, maximum percentage. Surety policy issued Surety policy issued Surety policy issued Aggregate amount of commercial paper outstanding Commercial Paper Lease obligations Contractual Obligation Letters of credit Letters of Credit Outstanding, Amount Debt instrument, term Expiration Period Expiration Period Number of seats in investment committee retained by Company Number Of Seats On Investment Committee Retained By Company Number Of Seats On Investment Committee Retained By Company Number of seats in investment committee Number Of Seats On Investment Committee Number Of Seats On Investment Committee Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] LIBOR London Interbank Offered Rate (LIBOR) [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] 3.875% Convertible Senior Debentures, due November 1, 2029 Three Point Eight Seven Five Percentage Convertible Senior Debentures Due Two Thousand Twenty Nine [Member] 3.875% Convertible Senior Debentures, due, 2029. Structured Notes Structured Notes [Member] Structured Notes [Member] Revolving Credit Facility Revolving Credit Facility [Member] Revolving Credit Facility and Term Loan Revolving Credit Facility And Term Loan [Member] Revolving Credit Facility And Term Loan [Member] Senior Notes Due 2030 Senior Notes Due 2030 [Member] Senior Notes Due 2030 [Member] Senior Notes Due 2027 Senior Notes Due 2027 [Member] Senior Notes Due 2027 [Member] Reducing Revolver Loan Reducing Revolver Loan [Member] Reducing Revolver Loan [Member] Foursight Credit Facilities Foursight Credit Facilities [Member] Foursight Credit Facilities [Member] Jefferies Jefferies [Member] Jefferies LLC [Member] Foursight Capital Foursight Capital [Member] Foursight Capital [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Senior Notes Senior Notes [Member] Credit Facility Line of Credit [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Assets pledged for indebtedness Assets pledged for indebtedness Assets pledged for indebtedness Nonrecourse indebtedness collateralized by assets Secured Debt Structured notes matures in 2018 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months Debt subject to mandatory redemption, 2019 Long-term Debt, Maturities, Repayments of Principal in Year Two Debt subject to mandatory redemption, 2020 Long-term Debt, Maturities, Repayments of Principal in Year Three Debt subject to mandatory redemption, 2021 Long-term Debt, Maturities, Repayments of Principal in Year Four Structured notes matures in 2022 Long-term Debt, Maturities, Repayments of Principal in Year Five Debt called amount Extinguishment of Debt, Amount Interest rate Debt Instrument, Interest Rate, Stated Percentage Debt instrument, face amount Debt Instrument, Face Amount Redemption price as percentage of principal amount redeemed Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed Debt Instrument, Principal Amount of Debt Issued, Net of Retirements Debt Instrument, Principal Amount of Debt Issued, Net of Retirements Debt Instrument, Principal Amount of Debt Issued, Net of Retirements Long-term debt, fair value Long-term Debt, Fair Value Credit facility term loan, maximum amount Line of Credit Facility, Maximum Borrowing Capacity Decrease on each annual anniversary of debt agreement Line of Credit Facility, Decrease On Each Annual Anniversary Of Debt Agreement Line of Credit Facility, Decrease On Each Annual Anniversary Of Debt Agreement Amount drawn on debt Debt Instrument, Amount Drawn Debt Instrument, Amount Drawn Percentage added to base rate or LIBOR rate Debt Instrument, Basis Spread on Variable Rate Aggregate outstanding letters of credit Amount of revolver available Revolving Credit Facility, Amount Available Revolving Credit Facility, Amount Available Number of warehouse credit commitment Number of Warehouse Credit Commitment Number of Warehouse Credit Commitment Property, Equipment and Leasehold Improvements, Net Property, Plant and Equipment Disclosure [Text Block] Equity Method Investments and Joint Ventures [Abstract] Investment [Table] Investment [Table] Joint Venture Cash Flows Allocation Plans [Axis] Joint Venture Cash Flows Allocation Plans [Axis] Joint Venture Cash Flows Allocation Plans [Axis] Joint Venture Cash Flows Allocation Plans [Domain] Joint Venture Cash Flows Allocation Plans [Domain] [Domain] for Joint Venture Cash Flows Allocation Plans [Axis] Plan One Plan One [Member] Plan One [Member] Plan Two Plan Two [Member] Plan Two [Member] Plan Three Plan Three [Member] Plan Three [Member] Garcadia Companies Garcadia [Member] Garcadia Garff Enterprises, Inc Garff Enterprises, Inc [Member] Garff Enterprises, Inc [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Garff Corporate Joint Venture [Member] Investment [Line Items] Investment [Line Items] Number of automobile dealerships Number of Automobile Dealerships Number of automobile dealership. Corporate Joint Venture, Percentage of Cash Flows Allocated Corporate Joint Venture, Percentage of Cash Flows Allocated Corporate Joint Venture, Percentage of Cash Flows Allocated Fair Value Disclosures [Abstract] Fair Value, Option, Quantitative Disclosures [Table] Fair Value, Option, Quantitative Disclosures [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Long-term debt Long-term Debt [Member] Short-term borrowings Short-term Debt [Member] Securities or Other Assets Sold under Agreements to Repurchase [Axis] Securities or Other Assets Sold under Agreements to Repurchase [Axis] Assets Sold under Agreements to Repurchase, Type [Domain] Assets Sold under Agreements to Repurchase, Type [Domain] Financial instruments sold Financial Instruments Sold [Member] Financial Instruments Sold [Member] Fair Value, Option, Quantitative Disclosures [Line Items] Fair Value, Option, Quantitative Disclosures [Line Items] Loans and other receivables Fair Value, Option, Credit Risk, Gains (Losses) on Assets Loans Fair Value, Option, Credit Risk, Gains (Losses) on Loans Fair Value, Option, Credit Risk, Gains (Losses) on Loans Loan commitments Fair Value, Option, Credit Risk, Gains (Losses) on Liabilities Other changes in fair value Fair Value, Option, Changes in Fair Value, Gain (Loss) Equity commitment Equity Commitment Equity commitment. Funded equity commitments Funded Equity Commitments Funded amount of the committed equity capitalization at the balance sheet date. Investment commitment extension Investment Commitment Extension Period Investment Commitment Extension Period Termination notice Termination Notice Termination Notice Total line of credit facility commitment under joint venture Total line of credit facility commitment under joint venture Total line of credit facility commitment under joint venture. Credit facility, extension period Line of Credit Facility, Extension Period Line of Credit Facility, Extension Period Funded portion of line of credit commitment Interest income and unfunded commitment fees related to facility commitment Interest Income And Unfunded Commitment Fees Related To Facility Commitment Interest Income And Unfunded Commitment Fees Related To Facility Commitment Investment banking Investment Banking Revenue Origination fees Loan Processing Fee Placement agent fees Placement Agent Fees Placement Agent Fees Service fee income Service Fee Income Service Fee Income Other assets Payables, expense accruals and other liabilities Payables, expense accruals and other liabilities Payables, expense accruals and other liabilities Net underwriting fees Fees and Commissions Trading assets, at fair value Financial instruments owned trading assets, at fair value Financial Instruments, Owned, Trading Assets, at Fair Value Common Shares Subject to Option Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Beginning balance (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Granted (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Exercised (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Cancelled (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Ending balance (shares) Exercisable (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted- Average Exercise Prices Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Weighted-Average Exercise Prices, Beginning balance (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Weighted-Average Exercise Prices, Granted (USD per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Weighted-Average Exercise Prices, Exercised (USD per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Weighted-Average Exercise Prices, Cancelled (USD per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Weighted-Average Exercise Prices, Ending balance (USD per share) Weighted-Average Exercise Prices, Exercisable (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted-Average Remaining Contractual Term Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Weighted-Average Remaining Contractual Term, Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Aggregate Intrinsic Value, Exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Aggregate Intrinsic Value, Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Aggregate Intrinsic Value, Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Collateralized Transactions [Abstract] Collateralized Transactions [Abstract] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Corporate equity securities Equity Securities [Member] Corporate debt securities Corporate Debt Securities [Member] Mortgage- and asset-backed securities Collateralized Mortgage Backed Securities and Asset-backed Securities [Member] Collateralized Mortgage Backed Securities and Asset-backed Securities [Member] U.S. government and federal agency securities US Government Corporations and Agencies Securities [Member] Municipal securities Municipal Bonds [Member] Sovereign securities Sovereign Debt Securities [Member] Loans and other receivables Loans and Finance Receivables [Member] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Securities Lending Arrangements Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred Repurchase Agreements Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement Total Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement Linkem Linkem [Member] Linkem [Member] Percentage of ownership owned Equity Method Investment, Ownership Percentage Dividend rate on preferred stock Preferred Stock, Dividend Rate, Percentage Percentage of ownership upon conversion of preferred shares Ownership Percentage Upon Conversion Of Preferred Shares Ownership Percentage Upon Conversion of Preferred Shares Percentage of total voting securities Equity Method Investment, Voting Percentage The voting percentage of common stock or equity participation in the investee accounted for under the equity method of accounting. Excess investment amortization period, years Excess investment amortization period Excess investment amortization period Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Forecast Scenario, Forecast [Member] Dividend Equivalents Dividend Equivalents [Member] Dividend Equivalents [Member] Growth Rate Benchmark [Axis] Growth Rate Benchmark [Axis] Growth Rate Benchmark [Axis] Growth Rate Category [Domain] Growth Rate Category [Domain] [Domain] for Growth Rate Category [Axis] Benchmark Two Benchmark Two [Member] Benchmark Two [Member] Benchmark Three Benchmark Three [Member] Benchmark Three [Member] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Senior Executives Senior Executives [Member] Senior Executives [Member] Senior Executive Compensation Plan Senior Executive Compensation Plan [Member] Senior Executive Compensation Plan [Member] 2016 Plan Senior Executive Compensation Plan 2016 [Member] Senior Executive Compensation Plan 2016 [Member] 2017 Plan Senior Executives Compensation Plan 2017 [Member] Senior Executives Compensation Plan 2017 [Member] 2018 Plan Senior Executives Compensation Plan 2018 [Member] Senior Executives Compensation Plan 2018 [Member] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Long-term Cash Long-term Cash [Member] Long-term Cash [Member] Award performance measurement period Employee Service Share-Based Compensation, Performance Measurement Period Employee Service Share-based Compensation, Performance Measurement Period Number of awards eligible Employee Service Share-Based Compensation, Number Of Award Eligible Employee Service Share-based Compensation, Number of Award Eligible Percentage of compensation beyond base salary will be performance-based Employee Service Share-Based Compensation, Percentage Of Compensation Beyond Base Salary Will Be Performance-Based Employee Service Share-based Compensation, Percentage of Compensation Beyond Base Salary Will Be Performance-based Employee service share-based compensation, holding period Employee Service Share-based Compensation, Holding Period Employee Service Share-based Compensation, Holding Period Stock price (USD per share) Share Price Performance measurement benchmark, percentage Employee Service Share-based Compensation, Performance Measurement Benchmark, Percentage Employee Service Share-based Compensation, Performance Measurement Benchmark, Percentage Additional incentive compensation, percentage Employee Service Share-Based Compensation, Additional Incentive Compensation, Percentage Employee Service Share-based Compensation, Additional Incentive Compensation, Percentage Dividend equivalents declared on restricted stock units Dividend Equivalents Declared On Restricted Stock Units Dividend equivalents declared on restricted stock units. Grants, weighted average grant date fair value (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Employee Service Share-based Compensation, Performance Measurement, Targeted Long-Term Compensation Employee Service Share-based Compensation, Performance Measurement, Targeted Long-Term Compensation Employee Service Share-based Compensation, Performance Measurement, Targeted Long-Term Compensation Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Trading Securities Trading Securities [Member] Investment in FXCM Investment in FXCM [Member] Investment in FXCM [Member] FXCM Fxcm [Member] FXCM Global Brokerage Global Brokerage Holdings [Member] Global Brokerage Holdings [Member] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Senior secured term loan receivable Senior secured term loan receivable Senior secured term loan receivable Loan receivable interest rate percentage Loan Receivable Interest Rate Percentage Loan Receivable Interest Rate Percentage Increase in Interest rate per annum each quarter Loan Receivable Interest Rate Increase Loan Receivable Interest Rate Increase Principal and interest payments received Principal and Interest Received Principal and interest received Loan receivable interest rate during period Loan Receivable Interest Rate During Period Loan Receivable Interest Rate during Period Principal, interest and fees received Principal, Interest And Fees Received Principal, Interest And Fees Received Initial investment amount Initial Investment Amount Initial Investment Amount Unrealized and realized gains and interest income Principal Transactions Revenue, Net Maximum percentage of all distributions Equity Method Investment, Maximum Percentage of All Distributions Equity Method Investment, Maximum Percentage of All Distributions Number of board of directors Number Of Directors on Board Number Of Directors on Board Number of directors appointed by Company Number of Directors Appointed by Company Number of Directors Appointed by Company Percentage of distributions from sale of assets or certain other events until loan repayment Percentage of distributions from sale of assets or certain other events until loan repayment Percentage of distributions from sale of assets or certain other events until loan repayment Percentage of distributions from sale of assets or certain other events until next milestone amount Percentage of distributions from sale of assets or certain other events until next milestone amount Percentage of distributions from sale of assets or certain other events until next milestone amount Distributions milestone after loan repayment Distributions milestone after loan repayment Distributions milestone after loan repayment Percentage of distributions from sale of assets or certain other events until milestone two Percentage of distributions from sale of assets or certain other events until milestone two Percentage of distributions from sale of assets or certain other events until milestone two Percentage of distributions from sale of assets or certain other events thereafter Percentage of distributions from sale of assets or certain other events thereafter Percentage of distributions from sale of assets or certain other events thereafter Distributions milestone two after loan repayment Distributions milestone two after loan repayment Distributions milestone two after loan repayment Number of terminated employees as percentage of global workforce Restructuring and Related Cost, Expected Number of Positions Eliminated, As Percentage of Global Workforce Restructuring and Related Cost, Expected Number of Positions Eliminated, As Percentage of Global Workforce FXCM term loan Fair Value of Senior Secured Term Loan Receivable Fair Value of Senior Secured Term Loan Receivable Equity method investments Equity Method Investments Carrying value of Senior Secured Term Loan receivable and rights to future distributions Senior Secured Term Loan Receivable and Loans to and Investments in Associated Companies Senior Secured Term Loan Receivable and Loans to and Investments in Associated Companies Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying Amount Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] 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] Notes and loans receivable Notes and Loans Receivable Notes and loans receivable Short-term borrowings Short-term Debt Disposal Group, Including Discontinued Operation, Additional Disclosures [Abstract] Discontinued Operations and Assets Held for Sale Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Selected Quarterly Financial Information [Abstract] Selected Quarterly Financial Data Quarterly Financial Information [Text Block] Nonoperating Income (Expense) [Abstract] Other Results of Operations Information Other Results Of Operations Information Text Block Other Results of Operations Information. Available for Sale Securities Investment Holdings [Text Block] HomeFed Homefed Corporation [Member] HomeFed Corporation - Member Company Chairman Company Chairman [Member] Company Chairman [Member] Shares of common stock owned Investment Owned, Balance, Shares Maximum voting rights as a percentage of total voting securities voting Percentage Limit Of Voting Rights Contractually Agreed Percentage Limit Of Voting Rights Contractually Agreed Ownership percentage of company Ownership Percentage of Company Ownership Percentage of Company Number of executives from the Company Schedule Of Assets And Liabilities Measured On Recurring Basis At Fair Value Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Investments Measured At Fair Value Based On Net Asset Value Investments Measured At Fair Value Based On Net Asset Value [Table Text Block] Investments Measured At Fair Value Based On Net Asset Value Summary Of Changes In Fair Value Of Financial Assets And Liabilities Classified As Level 3 Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table Text Block] Reconciliation of beginning Level 3 assets and liabilities to ending Level 3 assets and liabilities (specifically disaggregating purchases, sales, settlements, issuances, transfers to Level 3 and transfers out of Level 3). Quantitative Information About Significant Unobservable Inputs Used In Level 3 Fair Value Measurements Fair Value Inputs Assets And Liabilities Quantitative Information [Table Text Block] Tabular disclosure of quantitative information about significant unobservable inputs used in the fair value measurement of Level 3 financial assets and liabilities, including valuation technique and range of inputs Summary Of Gains (Losses) Due To Changes In Instrument Specific Credit Risk For Loans and Other Receivables And Loan Commitments Measured At Fair Value Under Fair Value Option Fair Value, Option, Quantitative Disclosures [Table Text Block] Summary Of Amount By Which Contractual Principal Exceeds Fair Value For Loans And Other Receivables Measured At Fair Value Under Fair Value Option Schedule Of Financial Instrument Contractual Principal In Excess Of Fair Value [Table Text Block] Schedule of financial instrument contractual principal in excess of fair value. Segment Reporting [Abstract] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Americas Americas [Member] Europe Europe [Member] Asia Asia [Member] Revenues from External Customers and Long-Lived Assets [Line Items] Revenues from External Customers and Long-Lived Assets [Line Items] Net revenues Revenues, Net of Interest Expense Condensed Financial Statements [Table] Condensed Financial Statements [Table] Condensed Financial Statements, Captions [Line Items] Condensed Financial Statements, Captions [Line Items] Supplemental Cash Flow Information Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Temporary Equity Disclosure [Abstract] Redeemable Noncontrolling Interest, by Legal Entity [Table] Redeemable Noncontrolling Interest, by Legal Entity [Table] Redeemable Noncontrolling Interest [Line Items] Redeemable Noncontrolling Interest [Line Items] Redeemable Noncontrolling Interest [Roll Forward] Redeemable Noncontrolling Interest [Roll Forward] Redeemable Noncontrolling Interest [Roll Forward] Beginning balance Redeemable Noncontrolling Interests Carrying Amount Redeemable Noncontrolling Interests Carrying Amount Income allocated to redeemable noncontrolling interests Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Distributions to redeemable noncontrolling interests Distributions To Redeemable Noncontrolling Interests Distributions To Redeemable Noncontrolling Interests Increase in fair value of redeemable noncontrolling interests charged to additional paid-in capital Change In Fair Value Of Redeemable Noncontrolling Interests Change In Fair Value Of Redeemable Noncontrolling Interests Ending balance Brokers and Dealers [Abstract] Net Capital Requirements [Table] Net Capital Requirements [Table] Net Capital Requirements [Table] Jefferies LLC Jefferies LLC [Member] Jefferies LLC [Member] Net Capital Requirements [Line Items] Net Capital Requirements [Line Items] Net Capital Requirements [Line Items] Net Capital Net Capital Excess Net Capital Alternative Excess Net Capital Statement of Comprehensive Income [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Net unrealized holding gains (losses) on investments arising during the period, net of income tax provision (benefit) of $3,450, $2,262 and $(5,029) Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Less: reclassification adjustment for net (gains) losses included in net income, net of income tax provision (benefit) of $124, $2 and $6,068 Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Net change in unrealized holding gains (losses) on investments, net of income tax provision (benefit) of $3,326, $2,260 and $(11,097) Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Net unrealized foreign exchange gains (losses) arising during the period, net of income tax provision (benefit) of $14,616, $(3,530) and $(5,174) Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Less: reclassification adjustment for foreign exchange (gains) losses included in net income, net of income tax provision (benefit) of $1,086, $0 and $0 Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax Net change in unrealized foreign exchange gains (losses), net of income tax provision (benefit) of $13,530, $(3,530) and $(5,174) Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Net unrealized gains (losses) on instrument specific credit risk arising during the period, net of income tax provision (benefit) of $(13,215), $(4,251) and $0 Other Comprehensive Income (Loss), Unrealized Gains (Losses) On Instrument Specific Credit Risk Arising During Period, Net Of Tax Other Comprehensive Income (Loss), Unrealized Gains (Losses) On Instrument Specific Credit Risk Arising During Period, Net Of Tax Net change in unrealized instrument specific credit risk gains (losses), net of income tax provision (benefit) of $(13,215), $(4,251) and $0 Other Comprehensive Income (Loss), Unrealized Gains (Losses) On Instrument Specific Credit Risk Adjustment During Period, Net Of Tax Other Comprehensive Income (Loss), Unrealized Gains (Losses) On Instrument Specific Credit Risk Adjustment During Period, Net Of Tax Net unrealized gains (losses) on cash flow hedges arising during the period, net of income tax provision (benefit) of $(593), $0 and $0 Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Net change in unrealized cash flow hedges gains (losses), net of income tax provision (benefit) of $(593), $0 and $0 Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Net pension gains (losses) arising during the period, net of income tax provision (benefit) of $2,018, $(2,516) and $7,152 Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax Less: reclassification adjustment for pension (gains) losses included in net income, net of income tax provision (benefit) of $(2,042), $(700) and $(17,159) Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax Net change in pension liability benefits, net of income tax provision (benefit) of $4,060, $(1,816) and $24,311 Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Other comprehensive income (loss), net of income taxes Other Comprehensive Income (Loss), Net of Tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive loss attributable to the noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive (income) loss attributable to the redeemable noncontrolling interests Comprehensive Income (Loss) Net Of Tax Attributable To Redeemable Noncontrolling Interests Comprehensive income or loss net of tax attributable to redeemable noncontrolling interests. Preferred stock dividends Preferred Stock Dividends, Income Statement Impact Comprehensive income (loss) attributable to Leucadia National Corporation common shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] U.S. Pension Plans United States Pension Plan of US Entity [Member] German Pension Plan Foreign Pension Plan [Member] Defined Benefit Plan, Asset Categories [Axis] Defined Benefit Plan, Asset Categories [Axis] Plan Asset Categories [Domain] Plan Asset Categories [Domain] WilTel Plan WilTel [Member] WilTel [Member] Jefferies Bache Limited Jefferies Bache Limited [Member] Jefferies Bache Limited [Member] Pension Plan Disclosure [Line Items] Pension Plan Disclosure [Line Items] Pension Plan Disclosure [Line Items] Number of participants offered Pension Settlement Arrangements, Numbers of Participants Offered Pension Settlement Arrangements, Numbers of Participants Offered Number of participants accepted Pension Settlement Arrangements, Numbers of Participants Accepted Pension Settlement Arrangements, Numbers of Participants Accepted Distributions paid Pension Settlement Arrangements, Distributions Paid Pension Settlement Arrangements, Distributions Paid Settlement charge Defined Benefit Plan, Settlements, Benefit Obligation Charge to accumulated other comprehensive income (loss) Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax Accrued pension cost Pension and Other Postretirement Defined Benefit Plans, Liabilities Estimated net loss that will be amortized from AOCI next year Defined Benefit Plan, Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year Estimated employer contributions in next fiscal year Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year Number of portfolios Plan Assets, Number of Portfolios Plan Assets, Number of Portfolios Current expected inflation rate Current Expected Inflation Rate Current Expected Inflation Rate Long duration risk free real rate of return Long Duration Risk Free Real Rate of Return Long Duration Risk Free Real Rate of Return Return premium for corporate credit risk Rate of Return Premium for Corporate Credit Risk Rate of Return Premium for Corporate Credit Risk Equity risk premium over cash Equity Risk Premium over Cash Equity Risk Premium over Cash Expected long-term rate of return assumption Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets Investment in Insurance contract Investment In Insurance Contract Investment in insurance contract. Payment to transfer defined benefit pension obligations and insurance contracts Defined Benefit Plan, Payment To Transfer Defined Benefit Obligation And Insurance Contracts Defined Benefit Plan, Payment To Transfer Defined Benefit Obligation And Insurance Contracts Consideration for release indemnity relating to pension obligation Consideration For Release of Indemnity Relating To Pension Obligations Consideration For Release of Indemnity Relating To Pension Obligations Pension expense Defined Contribution Plan, Cost Recognized Net Capital Requirements Regulatory Capital Requirements Disclosure [Text Block] Regulatory capital requirements disclosure. Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) [Table] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Interest rate swaps Derivative Financial Instruments, Liabilities [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest rate contracts Interest Rate Contract [Member] Foreign exchange contracts Foreign Exchange Contract [Member] Equity contracts Equity Contract [Member] Commodity contracts Commodity Contract [Member] Credit contracts Credit Risk Contract [Member] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Gains (losses) recognized in Interest expense of Jefferies Gain (Loss) on Fair Value Hedges Recognized in Earnings Unrealized and realized gains (losses) Gain (Loss) on Derivative Instruments, Net, Pretax Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Held-for-sale Disposal Group, Held-for-sale, Not Discontinued Operations [Member] Disposal Groups, Including Discontinued Operations, Name [Domain] Ownership percentage Ownership Percentage Ownership Percentage Cash consideration from sale of business Proceeds from Divestiture of Businesses Potential earn-out payment to be received from sale of subsidiary Disposal Group, Potential Earn-out Payment to be Received Disposal Group, Potential Earn-out Payment to be Received Net book value Disposal Group, Not Discontinued Operation, Net Book Value Disposal Group, Not Discontinued Operation, Net Book Value Pre-tax gain on disposal Liabilities held for sale Disposal Group, Including Discontinued Operation, Liabilities Investments in and Advances to Affiliates [Table] Investments in and Advances to Affiliates [Table] Associated Companies Associated Companies [Member] Associated Companies [Member] Investments in and Advances to Affiliates [Line Items] Investments in and Advances to Affiliates [Line Items] Assets Liabilities Revenues Total revenues of associated companies Total revenues of associated companies Income from continuing operations before extraordinary items Associated Companies Investments Summarized Financial Information Income Loss From Continuing Operations Before Extraordinary Items Associated Companies Investments Summarized Financial Information Income Loss From Continuing Operations Before Extraordinary Items Net income Net Income Loss Of Associated Companies Net Income Loss Of Associated Companies The Company’s income related to associated companies Undistributed earnings of equity method investments Undistributed Earnings of Equity Method Investments Undistributed Earnings of Equity Method Investments Accounting Policies [Abstract] Consolidation Consolidation, Policy [Policy Text Block] Revenue Recognition Policies Revenue Recognition, Policy [Policy Text Block] Hedge Accounting Derivatives, Methods of Accounting, Hedging Derivatives [Policy Text Block] Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Cash and Securities Segregated and on Deposit for Regulatory Purposes or Deposited With Clearing and Depository Organizations Cash And Securities Segregated And On Deposit For Regulatory Purposes Or Deposited With Clearing And Depository Organizations Policy [Text Block] Cash and Securities Segregated and on Deposit for Regulatory Purposes or Deposited With Clearing and Depository Organizations. Financial Instruments and Fair Value Fair Value of Financial Instruments, Policy [Policy Text Block] Fair Value Hierarchy Fair Value Measurement, Policy [Policy Text Block] Valuation Process for Financial Instruments Valuation Process for Financial Instruments [Policy Text Block] Valuation Process for Financial Instruments [Policy Text Block] Investments in Managed Funds Investments In Managed Funds Policy [Text Block] Disclosure of accounting policy for investments in managed funds and related-party managed funds accounted for under the equity method or fair value. Loans to and Investments in Associated Companies Loans to and Investments in Associated Companies [Policy Text Block] Loans to and Investments in Associated Companies [Policy Text Block] Receivables Receivables and Provision for Doubtful Accounts [Policy Text Block] Receivables and Provision for Doubtful Accounts [Policy Text Block] Securities Borrowed And Securities Loaned Securities Borrowed and Loaned Policy [Policy Text Block] Securities Purchased Under Agreements to Resell and Securities Sold Under Agreements to Repurchase Repurchase and Resale Agreements Policy [Policy Text Block] Property, Equipment and Leasehold Improvements Property, Plant and Equipment, Policy [Policy Text Block] Impairment of Long-Lived Assets Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Intangible Assets, Net and Goodwill Goodwill and Intangible Assets, Policy [Policy Text Block] Inventories and Cost of Sales Inventory, Policy [Policy Text Block] Payables, Expense Accruals and other Liabilities Payables, Expense Accruals and Other Liabilities [Policy Text Block] Payables, Expense Accruals and Other Liabilities [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Share-based Compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Foreign Currency Translation Foreign Currency Transactions and Translations Policy [Policy Text Block] Earnings per Common Share Earnings Per Share, Policy [Policy Text Block] Securitization Activities Transfers and Servicing of Financial Assets, Policy [Policy Text Block] Contingencies Commitments and Contingencies, Policy [Policy Text Block] Accounting Developments New Accounting Pronouncements, Policy [Policy Text Block] Collateralized Transactions Collateralized Financing Transactions [Text Block] Collateralized financing transactions. Schedule I - Condensed Financial Information of Registrant Condensed Financial Information of Parent Company Only Disclosure [Text Block] Accumulated Other Comprehensive Income Accumulated Other Comprehensive Income [Text Block] Accumulated Other Comprehensive Income [Text Block] Income Tax Disclosure [Abstract] Balance at beginning of period Unrecognized Tax Benefits Increases based on tax positions related to current period Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Increases based on tax positions related to prior periods Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Decreases based on tax positions related to prior periods Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Decreases related to settlements with taxing authorities Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities Balance at end of period Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Projected benefit obligation Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Net periodic pension benefit cost Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Discount rate Summary Of Property, Equipment And Leasehold Improvements Property, Plant and Equipment [Table Text Block] Offsetting [Abstract] Summary Of Offsetting Assets And Liabilities Offsetting Assets and Liabilities [Table Text Block] Offsetting Assets and Liabilities [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Nature of Operations Nature of Operations [Text Block] Document And Entity Information [Abstract] Document and Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Entity Central Index Key Entity Central Index Key Entity Registrant Name Entity Registrant Name Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Public Float Entity Public Float Earnings Per Share [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Stock options Employee Stock Option [Member] Redeemable Convertible Preferred Shares Redeemable Convertible Preferred Shares [Member] Redeemable Convertible Preferred Shares [Member] Investment Type [Axis] Investment Type [Axis] Investment [Domain] Investments [Domain] Warrants Warrant [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Securities excluded from computation of earnings per share amount Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Exercise price (USD per share) Class of Warrant or Right, Exercise Price per Share of Warrants or Rights Class of Warrant or Right, Exercise Price per Share of Warrants or Rights Convertible notes interest rate Number of common shares authorized to repurchase Stock Repurchase Program, Number of Shares Authorized to be Repurchased Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Income Statement [Abstract] Income tax provision (benefit) from discontinued operations Discontinued Operation, Tax Effect of Income (Loss) from Discontinued Operation During Phase-out Period Income tax provision (benefit) related to gain on disposal of discontinued operations Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation Gain (Loss) on Investments [Abstract] Net Realized Securities Gains (Losses) Gain (Loss) on Investments [Table Text Block] Schedule Of Other Income Schedule Of Other Income [Table Text Block] Schedule Of Other Income [Table Text Block] CLOs Collateralized Loan Obligations [Member] Consumer loan vehicles Consumer Loan [Member] Related party private equity vehicles Related Party Private Equity Vehicles [Member] Related Party Private Equity Vehicles [Member] Real estate investment vehicles Other private investment vehicles Other Private Investment Vehicles [Member] Other Private Investment Vehicles [Member] Financial statement carrying amount, assets Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets Financial statement carrying amount, liabilities Variable Interest Entity, Nonconsolidated, Carrying Amount, Liabilities Maximum Exposure to Loss Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount VIE Assets Variable Interest Entity, Assets of Non Consolidated Vie Variable Interest Entity, Assets of Non Consolidated Vie New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Sale of beef, pork and beef by-products Sale Of Beef, Pork And Beef By-Products [Member] Sale Of Beef, Pork And Beef By-Products [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Product Concentration Risk Product Concentration Risk [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Revenue Sales Revenue, Net [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2014-09 Accounting Standards Update 2014-09 [Member] Accounting Standards Update 2016-13 Accounting Standards Update 2016-13 [Member] Accounting Standards Update 2016-13 Accumulated Other Comprehensive Income (Loss) Retained Earnings Retained Earnings [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Reclassification of tax effects from accumulated other comprehensive income Tax Cuts And Jobs Act Of 2017 Reclassification From Aoci To Retained Earnings Amount of increase (decrease) in accumulated other comprehensive income (AOCI) for reclassification to retained earnings of tax effect from remeasurement of deferred tax pursuant to Tax Cuts and Jobs Act of 2017. 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