Cover [Abstract] Entity Registrant Name Entity Central Index Key Document Type Amendment Flag Current Fiscal Year End Date Entity Small Business Entity Shell Company Entity Emerging Growth Company Entity Current Reporting Status Document Period End Date Entity Filer Category Document Fiscal Period Focus Document Fiscal Year Focus Entity Common Stock Shares Outstanding Document Quarterly Report Document Transition Report Entity File Number Entity Incorporation State Country Code Entity Tax Identification Number Entity Address City Or Town Entity Address Address Line 2 Entity Address State Or Province Entity Address Postal Zip Code City Area Code Local Phone Number Security 12b Title Security Exchange Name Entity Interactive Data Current Entity Address Address Line 1 Trading Symbol CONSOLIDATED BALANCE SHEETS Assets Current assets: Cash and cash equivalents Investments [Investments] Receivables Inventories Other current assets Total current assets [Assets, Current] Property and equipment Operating lease assets Goodwill and other intangible assets Investment partnerships Other assets Total assets [Assets] Liabilities and shareholders' equity Liabilities Current liabilities: Accounts payable and accrued expenses Current portion of operating lease liabilities Current portion of notes payable and other borrowings Total current liabilities [Liabilities, Current] Long-term notes payable and other borrowings Operating lease liabilities Deferred taxes Asset retirement obligations Other liabilities Total liabilities [Liabilities] Shareholders' equity Common stock Additional paid-in capital Retained earnings Accumulated other comprehensive loss Treasury stock, at cost Biglari Holdings Inc. shareholders' equity Total liabilities and shareholders' equity [Liabilities and Equity] CONSOLIDATED STATEMENTS OF EARNINGS (Unaudited) Revenues Restaurant operations Insurance premiums and other Oil and gas Media and licensing Revenues [Revenues] Cost and expenses Restaurant cost of sales Insurance losses and underwriting expenses Oil and gas production costs Media and licensing costs Selling, general and administrative Impairments Depreciation and amortization Interest expense Total [Costs and Expenses] Other income Gain on debt extinguishment Investment gains Investment partnership gains (losses) Total [Other Income] Earnings (loss) before income taxes Income tax expense (benefit) Net earnings (loss) [Net Income (Loss) Attributable to Parent] Earnings per share Net earnings (loss) per equivalent Class A share * CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) Net earnings (loss) Other comprehensive income (loss): Foreign currency translation Other comprehensive income (loss), net Total comprehensive income (loss) CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) Operating activities Net earnings (loss) Adjustments to reconcile net earnings (loss) to operating cash flows: Depreciation and amortization Provision for deferred income taxes Asset impairments and other non-cash expenses (Gains) losses on disposal of assets Gain on debt extinguishment [Extinguishment of Debt, Amount] Investment gains [Gain (Loss) on Investments] Investment partnership (gains) losses Distributions from investment partnerships Changes in receivables and inventories Changes in other assets Changes in accounts payable and accrued expenses Net cash provided by operating activities [Net Cash Provided by (Used in) Operating Activities] Investing activities Capital expenditures [Payments to Acquire Property, Plant, and Equipment] Proceeds from property and equipment disposals Acquisition of business, net of cash acquired [Payments to Acquire Businesses, Net of Cash Acquired] Distributions from investment partnerships [General Partner Distributions] Purchases of limited partner interests Purchases of investments [Payments to Acquire Investments] Redemptions of fixed maturity securities Net cash used in investing activities [Net Cash Provided by (Used in) Investing Activities] Financing activities Proceeds from revolving credit facility Principal payments on long-term debt [Repayments of Long-term Debt] Principal payments on direct financing lease obligations [Principal payments on direct financing lease obligations] Net cash used in financing activities [Net Cash Provided by (Used in) Financing Activities] Effect of exchange rate changes on cash Decrease in cash, cash equivalents and restricted cash [Cash and Cash Equivalents, Period Increase (Decrease)] Cash, cash equivalents and restricted cash at beginning of year [Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents] Cash, cash equivalents and restricted cash at end of third quarter CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS EQUITY (Unaudited) Statement [Table] Statement [Line Items] Statement Equity Components [Axis] Common Stock Additional Paid-In Capital Retained Earnings Accumulated Other Comprehensive Income (Loss) Treasury Stock Balance, shares [Shares, Issued] Balance, amount Net earnings Adoption of accounting standards Other comprehensive income, net Adjustment to treasury stock for holdings in investment partnerships Balance, shares Balance, amount Summary of Significant Accounting Policies Note 1. Summary of Significant Accounting Policies Note 2. New Accounting Standards Note 3. Earnings Per Share Investments Note 4. Investments Investment Partnerships Note 5. Investment Partnerships Property and Equipment Note 6. Property and Equipment Goodwill and Other Intangible Assets Note 7. Goodwill and Other Intangible Assets Restaurant Operations Revenues Note 8. Restaurant Operations Revenues Accounts Payable and Accrued Expenses Note 9. Accounts Payable and Accrued Expenses Notes Payable and Other Borrowings Note 10. Notes Payable and Other Borrowings Leased Assets and Lease Commitments Note 11. Leased Assets and Lease Commitments Accumulated Other Comprehensive Income Note 12. Accumulated Other Comprehensive Income Income Taxes Note 13. Income Taxes Commitments and Contingencies Note 14. Commitments and Contingencies Fair Value of Financial Assets Note 15. Fair Value of Financial Assets Related Party Transactions Note 16. Related Party Transactions Business Segment Reporting Note 17. Business Segment Reporting Description of Business Business Acquisition Principles of Consolidation Change in Presentation Summary of outstanding shares Fair value and carrying value of our partnership interest Carrying value of investment partnerships net of deferred taxes Gains (loss) from investment partnerships Summarized financial information for equity in investment partnerships Schedule of Property and Equipment Schedule of goodwill Schedule of other intangible assets Restaurant Operations Revenues (Tables) Schedule of restaurant operations revenues Schedule of accounts payable and accrued expenses Schedule of notes payable and other borrowings Schedule of interest expense Schedule of lease cost Schedule of supplemental cash flow information related to leases Schedule of supplemental balance sheet information related to leases Schedule of weighted-average lease terms and discount rates Schedule of maturities of lease liabilities at September 30, 2020 Schedule of fair value assets Schedule of revenue by segment Schedule of earnings (losses) before income taxes by segment Ownership Axis Statement Class Of Stock Axis Mr. Biglari [Member] Class A Common Stock [Member] Class B Common Stock [Member] Equity method investment, ownership percentage Class A Common Stock [Member] Class B Common Stock [Member] Common stock authorized Common stock issued and outstanding Equivalent Class A weighted average number of common shares Equivalent Class A common stock outsanding Statement Business Segments Axis Southern Pioneer [Member] Available for sale investments Investments in equity securities and a related derivative position Gain on investment Fair value of investment Securities Financing Transaction [Axis] Fair Value [Member] Company Common Stock [Member] Carrying Value [Member] Partnership interest at Beginning Investment partnership gains (losses) [Income (Loss) from Equity Method Investments] Distributions (net of contributions) to investment partnerships Increase in proportionate share of Company stock held Partnership interest at Ending Carrying value of investment partnerships Deferred tax liability related to investment partnerships Carrying value of investment partnerships net of deferred taxes [Carrying value of investment partnerships net of deferred taxes] Gains (losses) on investment partnership Tax expense (benefit) Net earnings (loss) [Net earnings (loss)] Related Party Transactions By Related Party Axis Lion Fund [Member] Lion Fund II [Member] Total assets [Total assets] Total liabilities [Total liabilities] Revenue Earnings Biglari Holdings' ownership interest Proportionate share of Company stock held by investment partnerships at cost Land Buildings Land and leasehold improvements Equipment Oil and gas properties Construction in progress Property and equipment, gross Less accumulated depreciation and amortization [Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment] Property and equipment, net Oil and gas properties, depletion expenses Impairments charges Impairment to long-lived assets Goodwill, beginning balance [Goodwill] Goodwill from acquisition Change in foreign exchange rates during the first nine months of 2020 Goodwill, ending balance Fair Value By Asset Class Axis Indefinite Lived Intangible Assets By Major Class Axis Finite-Lived Intangible Assets [Member] Franchise Agreement [Member] Other [Member] Indefinite-lived Intangible Assets [Member] Trade names [Member] Gross carrying amount Accumulated amortization Total intangible assets Amortization expense Effect of preliminary price allocation on goodwill Impairment charges Net sales Franchise royalties and fees Franchise partner fees Other Restaurant operations revenue Accounts payable Gift card and other marketing Salaries and wages Taxes payable Insurance accruals Deferred revenue Other [Other Accrued Liabilities, Current] Accounts payable and accrued expenses [Accounts Payable and Accrued Liabilities, Noncurrent] Current portion of notes payable and other borrowings Notes Payable, Current [Abstract] Notes payable Unamortized original issue discount and debt issuance costs Western Sizzlin revolver Finance obligations Finance lease liabilities Total current portion of notes payable and other borrowings Long-term notes payable and other borrowings Notes Payable, Noncurrent [Abstract] Notes payable [Notes Payable, Noncurrent] Unamortized original issue discount and debt issuance costs [Unamortized original issue discount and debt issuance costs] Finance obligations [Long-term Debt and Lease Obligation] Finance lease liabilities [Finance Lease, Liability, Noncurrent] Total long-term notes payable and other borrowings Interest expense [Interest Expense, Debt] Interest on finance leases and obligations Total interest expense Subsequent Event Type [Axis] Debt Instrument Axis Subsequent Event [Member] Western Sizzlin [Member] Steak n Shake Credit Facility [Member] Secured debt retired Fair value of long-term debt Reduction in revolver Debt instrument, interest rate Debt instrument, face amount Debt instrument, maturity date Debt instrument, outstanding balance Loan amortization rate Debt, line of credit Finance lease costs: Amortization of right-of-use assets Interest on lease liabilities Operating lease costs Total lease costs Cash paid for amounts included in the measurement of lease liablities: Financing cash flows from finance leases Operating cash flows from finance leases Operating cash flows from operating leases Right-of-use assets obtained in exchange for lease obligations: Finance lease liabilities [Right-of-Use Asset Obtained in Exchange for Finance Lease Liability] Operating lease liabilities [Right-of-Use Asset Obtained in Exchange for Operating Lease Liability] Finance leases: Property and equipment, net [Capital Leases, Lessee Balance Sheet, Assets by Major Class, Other Property, Plant, and Equipment, Net] Current portion of notes payable and other borrowings Long-term notes payable and other borrowings Total finance lease liablities Weighted-average remaining lease terms: Finance leases Operating leases Weighted-average discount rates: Finance leases [Finance Lease, Weighted Average Discount Rate, Percent] Operating leases [Operating Lease, Weighted Average Discount Rate, Percent] Plan Name Axis Operating Leases [Member] Finance Leases [Member] 2020 2021 2022 2023 2024 After 2024 Total lease payments Less interest Total lease liabilities Accumulated other comprehensive loss increase/decrease Accumulated other comprehensive loss Income tax (benefit) expense Unrecognized tax benefits Investment partnership pretax gains (losses) Fair Value By Fair Value Hierarchy Level Axis Level 1 [Member] Level 2 [Member] Level 3 [Member] Assets Assets, Fair Value Disclosure [Abstract] Cash equivalents Equity securities Bonds Options on equity securities Non-qualified deferred compensation plan investments Total assets at fair value Services Agreement [Member] Biglari Entities [Member] Period fees payment Services fees Steak n Shake [Member] Western Sizzlin [Member] [Western Sizzlin [Member]] Total Restaurant Operations [Member] First Guard [Member] Southern Pioneer [Member] [Southern Pioneer [Member]] Total Insurance Operations [Member] Southern Oil [Member] Maxim [Member] Total revenues Product Or Service Axis Income Statement Location Axis Restaurant [Member] Steak n Shake [Member] [Steak n Shake [Member]] Western Sizzlin [Member] Total Restaurant Operations [Member] Operating Business [Member] First Guard [Member] Southern Pioneer [Member] Total Insurance Operations [Member] Southern Oil [Member] Maxim [Member] Corporate [Member] Corporate 1 [Member] Investment Gains [Member] Investment Partnership Gains (Losses) [Member] Total Corporate And Investments [Member] Reconciliation Of Segments [Member] Interest expense on notes payable and other borrowings [Member] Earnings (loss) before income taxes [Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest] Weighted average remaining lease term for finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and