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Note 6 - Fair Values of Assets and Liabilities - Summary of Fair Value Hierarchy for Liabilities (Details) Other Proceeds from issuance of Senior notes, net of issuance costs Proceeds from Issuance of Senior Long-Term Debt Note 6 - Fair Value of Assets and Liabilities - Reconciliation of Level 3 Liabilities (Details) Note 6 - Fair Values of Assets and Liabilities - Measurement Inputs (Details) Total Receivables [Member] Represents total receivables. Note 6 - Fair Values of Assets and Liabilities - Summary of Other Relevant Data (Details) Note 7 - Variable Interest Entities - Summary of Variable Interest Entities (Details) us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery Recoveries Note 8 - Leases - Lease Cost (Details) Schedules of Concentration of Risk, by Risk Factor [Table Text Block] Note 8 - Leases - Maturities of Lease Liabilities (Details) Note 9 - Notes Payable - Schedule of Notes Payable at Face Value and Notes Payable to Related Parties (Details) Note 9 - Notes Payable - Schedule of Notes Payable at Face Value and Notes Payable to Related Parties (Details) (Parentheticals) Note 10 - Commitments and Contingencies - Schedule of Concentrations (Details) Note 11 - Net Income Attributable to Controlling Interests Per Common Share - Summary of Earning Per Share (Details) Note 12 - Stock-based Compensation - Summary of Restricted Stock and Restricted Stock Units (Details) Note 12 - Stock-based Compensation - Summary of Outstanding Options (Details) us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests Series A preferred stock, 400,000 shares issued and outstanding (liquidation preference - $40.0 million) at June 30, 2026 and December 31, 2025 (Note 5) (1) Notes To Financial Statements Notes To Financial Statements [Abstract] Amortizing debt facilities us-gaap_EffectiveIncomeTaxRateContinuingOperations Effective Income Tax Rate Reconciliation, Percent Issued, weighted average exercise price (in dollars per share) Exercised, weighted average exercise price (in dollars per share) us-gaap_Dividends Dividends us-gaap_LaborAndRelatedExpense Salaries and benefits Increase (decrease) in income tax liability Prepaid expenses and other assets, net Asset Pledged as Collateral [Member] Weighted Average [Member] us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet Increase in uncollected fees on earning assets us-gaap_SharesOutstanding Balance (in shares) Balance (in shares) atlc_TemporaryEquityConversionPricePerShare Temporary Equity, Conversion Price Per Share (in dollars per share) Represents the conversion price per share used in the denominator of the calculation to determine the number of shares of common stock into which temporary equity is convertible. Preferred Stock [Text Block] Thereafter, gross Amount of lessee's undiscounted obligation for lease payment for operating lease due after fourth fiscal year following current fiscal year. atlc_LessorOperatingLeasePaymentToBeReceivedAfterYearFour Thereafter, payments received from sublease Amount of lease payment to be received by lessor for operating lease after fourth fiscal year following current fiscal year. us-gaap_PreferredStockDividendRatePercentage Preferred Stock, Dividend Rate, Percentage Dividends [Axis] Segment Reporting [Text Block] Dividends [Domain] Thereafter, net lease payment Amount of net lease payments for operating lease, due after fourth fiscal year following latest fiscal year. 2027, net lease payment Amount of net lease payments for operating lease, due in first fiscal year following latest fiscal year. Award Type [Axis] Segment Reporting [Table Text Block] Adjustments to reconcile net income to net cash provided by operating activities: Series B preferred stock, no par value, 3,584,646 shares issued and outstanding at June 30, 2026 (liquidation preference - $89.6 million); 3,584,131 shares issued and outstanding at December 31, 2025 (liquidation preference - $89.6 million) (1) Plan Name [Axis] us-gaap_Liabilities Total liabilities Plan Name [Domain] Liabilities us-gaap_AllocatedShareBasedCompensationExpense Share-Based Payment Arrangement, Expense us-gaap_LiabilitiesAndStockholdersEquity Total liabilities, shareholders' equity and temporary equity Pledged Status [Domain] Segment Reporting [Table] Pledged Status [Axis] us-gaap_ShareBasedCompensation Stock-based compensation costs Lessee, Lease, Description [Table] Share-Based Payment Arrangement [Text Block] Changes in assets and liabilities: Preferred stock, shares issued (in shares) Preferred stock, shares outstanding (in shares) us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life (Year) Preferred stock, liquidation preference Variable Interest Entity Disclosure [Text Block] Cash and cash equivalents, and restricted cash and cash equivalents at end of period us-gaap_PreferredUnitsIssued Preferred Units, Issued (in shares) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period (in shares) Net margin Net margin Series B Preferred Stock [Member] Other Secured Debt [Member] Related to other secured debt. us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect Net decrease in cash and cash equivalents and restricted cash and cash equivalents us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue Fair value Fair value us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents Cash and cash equivalents, and restricted cash and cash equivalents at end of period Series A Preferred Stock [Member] Preferred Units by Name [Axis] New Accounting Pronouncements, Policy [Policy Text Block] us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations Cash and cash equivalents and restricted cash equivalents at beginning of period Cash and cash equivalents and restricted cash equivalents at end of period Statement [Table] Credit Facility [Axis] Cash paid under operating leases, gross Decrease in lease liability Credit Facility [Domain] Revolving Credit Facility [Member] Loans at fair value Loans, interest and fees receivable, at fair value Variable rate Committed capacity Line of Credit Facility, Maximum Borrowing Capacity Contributions by owners of noncontrolling interests us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber Outstanding (in shares) Outstanding (in shares) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue Outstanding, weighted average grant date fair value (in dollars per share) Outstanding, weighted average grant date fair value (in dollars per share) Financing Receivable, Past Due [Table Text Block] Issued (in shares) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod Issued, weighted average grant date fair value (in dollars per share) Long-Term Debt, Type [Axis] us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod Forfeited (in shares) Product and Service [Domain] Product and Service [Axis] Revolving credit facilities Consolidated Entities [Axis] Consolidated Entities [Domain] Vested, weighted average grant date fair value (in dollars per share) us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod Vested (in shares) 2028, net lease payment Amount of net lease payments for operating lease, due in second fiscal year following latest fiscal year. Operating Lease, Liability and Payments to be Received, Maturity [Table Text Block] Th tabular disclosure of operating lease liability, both payments to be received as a lessor and payments to be made on liability as a lessee. us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue Gross, gross atlc_WeightedAverageNumberOfSharesUnvestedSharebasedPaymentAwardsBasic Weighted Average Number of Shares, Unvested Share-based Payment Awards, Basic (in shares) Represents basic weighted average number of shares related to unvested share-based payment awards. 2030, net lease payment Amount of net lease payments for operating lease, due in fourth fiscal year following latest fiscal year. 2029, net lease payment Amount net lease payments for operating lease, due in third fiscal year following latest fiscal year. Weighted average discount rate Accounts payable and accrued expenses Asset Class [Axis] Revolving Credit Facility, Expiring October 2031 [Member] Revolving Credit Facility, Expiring October 2031 2027, gross atlc_OperatingLeasesNetLeasePaymentsDueTotal Total lease payments, net lease payment Amount of net lease payments for operating lease. Revolving Credit Facility Expiring August 2028 [Member] Represents Revolving Credit Facility Expiring August 2028. Proceeds from earning assets us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) 2026 (Remainder of 2026), gross Exercisable (in shares) Exercisable, weighted average exercise price (in dollars per share) Measurement Frequency [Axis] 2029, gross us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber Outstanding (in shares) Outstanding (in shares) Assets Commitments and Contingencies Disclosure [Text Block] 2028, gross us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice Outstanding, weighted average exercise price (in dollars per share) Outstanding, weighted average exercise price (in dollars per share) Statement [Line Items] Liability Class [Axis] Commercial Paper Rates [Member] Related to commercial paper interest rates. Fair Value Hierarchy and NAV [Axis] 2030, gross Outstanding, aggregate intrinsic value Common stock, issued (in shares) Common stock, outstanding (in shares) Award Type [Domain] us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears 2030, payments received from sublease us-gaap_LessorOperatingLeasePaymentsToBeReceived Sublease income, payments received from sublease Common stock, authorized (in shares) us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths 2027, payments received from sublease us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear 2026 (Remainder of 2026), payments received from sublease us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears 2029, payments received from sublease atlc_SharebasedCompensationTaxChargesToAdditionalPaidInCapitalFromExerciseAndVesting Share-based Compensation, Tax Charges to Additional Paid in Capital From Exercise and Vesting The value of tax charges to additional paid in capital from exercise and vesting under share-based compensation. us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears 2028, payments received from sublease Common Stocks [Member] Represents common stocks. Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] us-gaap_ExtinguishmentOfDebtAmount Extinguishment of Debt, Amount Common stock, no par value, 150,000,000 shares authorized: 15,170,081 and 14,922,462 shares issued and outstanding at June 30, 2026 and December 31, 2025, respectively 2028 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo Income tax liability 2029 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree 2027 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths Proceeds from issuance of common stock Proceeds from Issuance of Common Stock us-gaap_ProceedsFromIssuanceOfPreferredStockAndPreferenceStock Proceeds from Issuance of Preferred Stock and Preference Stock Unpaid principal balance of loans at fair value and are 90 days or more past due (which also coincides with finance charge and fee non-accrual policies) over the fair value of such loans, interest and fees receivable us-gaap_PolicyTextBlockAbstract Accounting Policies 2026 (Remainder of 2026) us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear Noncontrolling interests contributions us-gaap_DisclosureTextBlockAbstract Notes to Financial Statements 2030 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour Auto Finance Receivables [Member] Represents auto finance receivable. us-gaap_TableTextBlock Notes Tables Revolving Credit Facility, Expiring April 2029 3 [Member] Revolving Credit Facility, Expiring April 2029 Subsequent Events [Text Block] Concentration Risk Type [Axis] Interchange Revenues, Other Revenue [Member] Represents interchange revenues included in other revenue. Service Charges and Other Customer Related Fees, Other Revenue [Member] Represents service charges and other customer related fees included in other revenue. Servicing Income, Other Revenue [Member] Represents serving income included in other revenue. Significant Accounting Policies [Text Block] us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount Less imputed interest, gross Revolving Credit Facility Expiring October 30, 2026 [Member] Represents Revolving Credit Facility Expiring October 30, 2026. Operating lease liabilities Operating lease liabilities Contractual Obligations [Member] Related to contractual obligations. Merchant Fees [Member] Represents merchant fees. Other Revenue [Member] Represents other revenue. Fair Value, Assets Measured on Recurring Basis [Table Text Block] Revolving Credit Facility Expiring September 15, 2027 [Member] The revolving credit facility expiring September 15, 2027. Notes Receivable [Member] Concentration Risk Type [Domain] us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue Balance Balance Capitalization, Equity [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Aggregate unpaid gross balance of loans carried at fair value Amount of aggregate unpaid gross balance of loans receivable at fair value. Revolving Credit Facility Expiring March 31, 2028 [Member] The revolving credit facility expiring March 31, 2028. Fair Value, Liabilities Measured on Recurring Basis [Table Text Block] Proceeds from recoveries on charged off receivables Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] atlc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetWriteOffs Changes in fair value due to current period finance and fee charge-offs Amount of write offs of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Changes in fair value of liabilities, included in earnings us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings Proceeds from borrowings Statement of Stockholders' Equity [Abstract] Intangible Asset, Finite-Lived, Class [Axis] Loss Contingencies [Table] Intangible Asset, Finite-Lived, Class [Domain] Statement of Cash Flows [Abstract] Senior Notes 2029 [Member] Represents the bond maturing on January 31, 2029 that takes priority over other debt securities sold by the issuer. In the event the issuer goes bankrupt, senior debt holders receive priority for (must receive) repayment prior to (relative to) junior and unsecured (general) creditors. Long-Term Debt, Type [Domain] us-gaap_LossContingencyEstimateOfPossibleLoss Loss Contingency, Estimate of Possible Loss Equity Components [Axis] Senior Notes 2026 [Member] Represents the bond maturing on November 30, 2026 that takes priority over other debt securities sold by the issuer. In the event the issuer goes bankrupt, senior debt holders receive priority for (must receive) repayment prior to (relative to) junior and unsecured (general) creditors. Proceeds from exercise of stock options Equity Component [Domain] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Equity [Text Block] Fair Value, Inputs, Level 1 [Member] Additional Paid-in Capital [Member] Retained Earnings [Member] us-gaap_CostOfGoodsAndServicesSold Card and loan servicing Financial Asset, Aging [Axis] Property at cost, net of depreciation Subsequent Event [Table] Financing Receivable, Current, Allowance for Credit Loss [Table Text Block] Financial Asset, Aging [Domain] Sale of Stock [Axis] atlc_PaymentsForPurchasesAndDevelopmentOfPropertyNetOfDisposals Purchases and development of property Represents payments to acquire and develop property, net of disposals. Financial Asset, 30 to 59 Days Past Due [Member] Stock-based compensation costs Fair Value Option, Disclosures [Table Text Block] Financial Asset, 60 to 89 Days Past Due [Member] Financial Asset, Equal to or Greater than 90 Days Past Due [Member] us-gaap_FairValueOptionCreditRiskGainsLossesOnAssets Fair Value, Option, Credit Risk, Gains (Losses) on Assets Share-Based Payment Arrangement, Option, Activity [Table Text Block] Aggregate fair value of loans at fair value that are 90 days or more past due (which also coincides with finance charge and fee non-accrual policies) Fair Value Disclosures [Text Block] Share-Based Payment Arrangement, Option [Member] Supplemental cash flow information atlc_ProceedsFromIssuanceOfSeniorLongtermDebtGross Proceeds from Issuance of Senior Long-Term Debt, Gross The cash inflow before issuance costs and discounting from a borrowing with the highest claim on the assets of the entity in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle, if longer). Class B Preferred Units [Member] Represents class B preferred units. atlc_PreferredUnitsIssuedPercentageOfPreferredReturn Preferred Units Issued, Percentage of Preferred Return Represents the percentage of preferred return that units carry to be paid quarterly. Preferred stock, shares issued (in shares) us-gaap_TemporaryEquitySharesIssued Temporary Equity, Shares Issued (in shares) Preferred stock, shares outstanding (in shares) us-gaap_TemporaryEquitySharesOutstanding atlc_PreferredUnitPurchasePrice Preferred Unit Purchase Price (in dollars per share) Represents the preferred unit purchase price. Secured Overnight Financing Rate (SOFR) [Member] Preferred stock, shares authorized (in shares) us-gaap_TemporaryEquitySharesAuthorized us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments Income from accretion of discount associated with Loans at amortized cost, net Customer Concentration Risk [Member] us-gaap_PreferredStockLiquidationPreference Preferred Stock, Liquidation Preference Per Share (in dollars per share) us-gaap_SeniorNotes Senior notes, net Public Offering [Member] Information related to the public offering. Lease, Cost [Table Text Block] Proceeds from issuance of Series B preferred stock, net of issuance costs Proceeds from issuance of capital stock which provides for a specific dividend that is paid to the shareholders before any dividends to common stockholders and which takes precedence over common stockholders in the event of liquidation, after issuance costs. us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod Expired/Forfeited (in shares) Common stock, par value (in dollars per share) Expired/Forfeited, weighted average exercise price (in dollars per share) us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization Accumulated amortization Revolving Credit Facility, Expiring February 2032 [Member] Revolving Credit Facility, Expiring February 2032 us-gaap_PaymentsToAcquireLoansAndLeasesHeldForInvestment Payment for Acquisition, Loan and Lease, Held-for-Investment 2026 (Remainder of 2026), net lease payment The net lease operating payments payable in the remainder of the fiscal year. Other Commitments [Axis] Other Commitments [Domain] Deferred revenue us-gaap_FinancingReceivableDeferredIncome Financing Receivable, Deferred Commitment Fee atlc_PreferredStockAggregateOfferingPrice Preferred Stock, Aggregate Offering Price Represents the aggregate offering price for preferred stock. Income before income taxes us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest Income (loss) before income taxes Income before income taxes Revolving Credit Facility, Expiring October 2033 [Member] Revolving Credit Facility, Expiring October 2033 Paid-in capital Debt Disclosure [Text Block] Noncontrolling interests Loans, Assets [Member] Loans, Assets 1 us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1 Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1 Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Month) Issuance of stock Lessee, Operating Leases [Text Block] us-gaap_StockRepurchasedAndRetiredDuringPeriodValue Stock Repurchased and Retired During Period, Value Intangible Assets, Finite-Lived, Policy [Policy Text Block] us-gaap_NoninterestExpense Total operating expenses Total operating expenses us-gaap_DebtInstrumentFaceAmount Debt Instrument, Face Amount Operating expenses: Weighted average interest rate Stock option exercises and proceeds related thereto Schedule of Debt [Table Text Block] Financial Asset, Not Past Due [Member] Issuance of stock (in shares) Stock Issued During Period, Shares, New Issues (in shares) Revolving credit facility, expiration date Debt Instrument, Name [Domain] Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Stock option exercises and proceeds related thereto (in shares) Exercised (in shares) Fixed rate Debt Instrument, Interest Rate, Stated Percentage Fair Value Measurement Inputs and Valuation Techniques [Table] Compensatory stock issuances, net of forfeitures (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures (in shares) Class of Stock [Domain] Related and Nonrelated Parties [Axis] us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings Dividends us-gaap_StockRepurchasedAndRetiredDuringPeriodShares Stock Repurchased and Retired During Period, Shares (in shares) us-gaap_TemporaryEquityRedemptionPricePerShare Temporary Equity, Redemption Price Per Share (in dollars per share) Schedule of Long-Term Debt Instruments [Table] us-gaap_IncrementalCommonSharesAttributableToConversionOfPreferredStock Incremental Common Shares Attributable to Dilutive Effect of Conversion of Preferred Stock (in shares) Debt Instrument [Axis] us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet Unamortized debt issuance costs and discounts Preferred stock, no par value (in dollars per share) us-gaap_TemporaryEquityParOrStatedValuePerShare Operating activities Investing activities us-gaap_NetCashProvidedByUsedInOperatingActivities Net cash provided by operating activities Financing activities us-gaap_NetCashProvidedByUsedInInvestingActivities Net cash used in investing activities Revolving Credit Facility Expiring May 15, 2030 [Member] Represents the credit facility expiring 05/15/2030. Intangible Asset, Finite-Lived, and Capitalized Cost, Software to be Sold, Leased, or Marketed, Estimated Amortization Expense [Table Text Block] us-gaap_NetCashProvidedByUsedInFinancingActivities Net cash (used in) provided by financing activities atlc_PolicyTable Preferred stock, liquidation preference us-gaap_TemporaryEquityLiquidationPreference Temporary Equity, Liquidation Preference Income from merchant fees associated with Loans at fair value Amount of fees associated with loans at fair value. atlc_PreferredUnitsRedemptionPricePerUnit Preferred Units, Redemption Price Per Unit (in dollars per share) Redemption price per unit for preferred units. atlc_PreferredUnitsSharesRedeemedDuringPeriod Preferred Units, Shares, Redeemed During Period (in shares) Number of preferred units redeemed during a period of time. Term Secured Overnight Financing Rate [Member] Represents Term Secured Overnight Financing Rate. Accounting Policies [Abstract] Segments [Domain] Changes in fair value of loans at fair value, included in earnings Amount of change in fair value of loans recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3). atlc_AggregateUnpaidPrincipalBalanceOfLoansReceivableAtFairValue Aggregate Unpaid Principal Balance of Loans Receivable at Fair Value Amount of aggregate unpaid principal balance of loans receivable at fair value. Receivable [Policy Text Block] Revolving Credit Facility Expiring August 30, 2027 [Member] Represents Revolving Credit Facility Expiring August 30, 2027. Segments [Axis] Largest Retail Partner E [Member] Represents Largest Retail Partner E. Measurement Input Type [Axis] Largest Retail Partner B [Member] Represents Largest Retail Partner B. Income Statement [Abstract] Largest Retail Partner A [Member] Represents Largest Retail Partner A. Largest Retail Partner D [Member] Represents Largest Retail Partner D. Largest Retail Partner C [Member] Represents Largest Retail Partner C. Net income attributable to common shareholders—diluted us-gaap_NumberOfOperatingSegments Number of Operating Segments us-gaap_NumberOfReportableSegments Number of Reportable Segments us-gaap_AmortizationOfDeferredLoanOriginationFeesNet Amortization of debt issuance costs atlc_AdditionalPreferredUnitsIssued Additional Preferred Units Issued (in shares) Represents the number of additional preferred units issued. Measurement Input, Discount Rate [Member] Net income attributable to controlling interests Net income attributable to controlling interests Net income attributable to common shareholders—basic Net income attributable to common shareholders Financial Asset, Past Due [Member] atlc_OperatingLeasesOptionsToExtendForAdditionalPeriodsRevolvingPeriods Operating Leases, Options to Extend for Additional Periods, Revolving Periods (Year) Represents the duration of the revolving periods that generally apply to options to extend some, but not necessarily all, operating leases for additional periods. us-gaap_AmortizationOfFinancingCosts Amortization of Debt Issuance Costs us-gaap_AmortizationOfIntangibleAssets Intangible Asset, Finite-Lived, Amortization Expense Measurement Input Type [Domain] us-gaap_OtherCommitment Other Commitment Contingent consideration, measurement input Contingent Consideration [Member] Represents contingent consideration. Bank Partner Fees [Member] Represents bank partner fees. Measurement Input, Charge-off Volatility [Member] Measurement input using charge-off volatility. Measurement Input, Customer Payment Rate [Member] Measurement input using customer payment rate. Bank partner fees, measurement input Value of input used to measure liability in bank partner fees. Contingent consideration Restricted Stock [Member] Measurement Input, Charge-off Rate [Member] Measurement input using charge-off rate. Accounting Standards Update and Change in Accounting Principle [Table] Income Tax, Policy [Policy Text Block] us-gaap_OtherNoninterestExpense Other Other Related and Nonrelated Parties [Domain] Effect of dilutive preferred stock dividends and discount accretion The effect of dilutive securities on the net income (loss) available to common stockholders. Finance and fees, added to the account balance Amount of finance and fees of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Common Shares [Member] Represents common shares. O2021A Dividends [Member] Represents price per share of yearly dividends. Other non-operating income Fair Value Hierarchy and NAV [Domain] Measurement Frequency [Domain] us-gaap_RepaymentsOfLongTermDebt Repayment of borrowings Mercury Financial LLC [Member] Represents the company Mercury Financial LLC. Statement of Financial Position [Abstract] Senior notes, net us-gaap_ConvertibleDebtFairValueDisclosures Schedule of Variable Interest Entities [Table Text Block] Total Changes in fair value of loans Change in Contingent consideration and other purchase price adjustments (3) Internally Developed Software [Member] Represents the internally developed software. atlc_BusinessCombinationEarnoutPercentOfReceivablesLessThanChargeoffLevels Business Combination, Earnout Percent of Receivables Less than Charge-off Levels The earnout percentage for the business combination based on the charge-off levels of the receivables. Cash paid for income taxes, net of refunds atlc_BusinessCombinationEarnoutPaymentPeriod Business Combination, Earnout Payment Period (Year) Represents the earnout payment period for the business combination. us-gaap_MarketingAndAdvertisingExpense Marketing and solicitation Variable Interest Entity, Primary Beneficiary [Member] Fees and related income on earning assets Fees and related income on earning assets Fees and related income on earning assets primarily include: (1) lending fees; (2) fees associated with our credit card receivables; (3) changes in the fair value of loans and fees receivable; (4) changes in fair value of notes payable associated with structured financings; (5) income on investments in previously charged-off receivables; (6) gross profits and losses from auto sales; (7) gains associated with investments in securities; and (8) gains realized associated with our settlement of litigation. Variable Interest Entity [Table] us-gaap_DepreciationNonproduction Depreciation and amortization Revolving Credit Facility Expiring April 20, 2029 [Member] Revolving Credit Facility Expiring April 20, 2029 Senior Notes 2030 [Member] Senior Notes 2030 Revolving Credit Facility Expiring June 21, 2027 [Member] Revolving Credit Facility Expiring June 21, 2027 Revolving Credit Facility Expiring July 1, 2029 [Member] Revolving Credit Facility Expiring July 1, 2029 Fair Value, Recurring [Member] Revolving Credit Facility Expiring July 20, 2029 [Member] Revolving Credit Facility Expiring July 20, 2029 atlc_UnrealizedGainOnLoansAndFeesReceivableAndUnderlyingNotesPayableHeldAtFairValue Changes in fair value of loans The aggregate increase (decrease) in the market value on loans and fees receivable and underlying notes payable held at fair value whose gains (losses) were included in earnings. Revolving Credit Facility Expiring August 5, 2027 [Member] Revolving Credit Facility Expiring August 5, 2027 Increase in accounts payable and accrued expenses us-gaap_PaymentsForRepurchaseOfCommonStock Purchase and retirement of outstanding stock and preferred units atlc_WeightedAverageRemainingAccretionPeriodOfDeferredRevenue Weighted Average Remaining Accretion Period of Deferred Revenue (Month) Represents the weighted average remaining accretion period of deferred revenue during the reporting period. Document Type Document Information [Line Items] Document Quarterly Report us-gaap_LesseeOperatingLeaseTermOfContract Lessee, Operating Lease, Term of Contract (Year) us-gaap_ConcentrationRiskPercentage1 Concentration Risk, Percentage Weighted average remaining lease term - months (Month) Document Information [Table] us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) Entity Interactive Data Current us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year) Document Transition Report Auto Finance [Member] Information related to auto finance. us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding Diluted (including unvested share-based payment awards) (1) (in shares) Credit and Other Investments [Member] Information related to credit and other investments. Notes Payable, net held by VIEs Notes payable, at face value Effect of dilutive stock compensation arrangements and exchange of preferred stock (in shares) Basic (including unvested share-based payment awards) (1) (in shares) Loans at amortized cost, net (including $3.7 million and $4.1 million of allowance for credit losses at June 30, 2026 and December 31, 2025, respectively; and $18.2 million and $20.1 million of deferred revenue at June 30, 2026 and December 31, 2025, respectively) Antidilutive Security, Excluded EPS Calculation [Table] Net income attributable to common shareholders per common share—basic (in dollars per share) us-gaap_NotesPayable Total notes payable outstanding, net Loans at amortized cost, net for which it is practicable to estimate fair value and which are carried at net amortized cost This item represents a financial instrument (as defined) for which it is practicable to estimate fair value. This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents loan receivable as presented on the statement of financial position which may include mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts, or any other loans which are due the Company as of the balance sheet date. Intangible assets, net (Note 2) Aggregate unpaid principal balance included within loans at fair value This item represents the aggregate unpaid principal balance within loans and fees receivables that are reported at fair value for which the fair value option has been elected. Loans and Fees Receivable Pledged as Collateral, Fair Value [Member] Information related to loans and fees receivable pledged as collateral measured at fair value. Loans and Fees Receivable at Fair Value [Member] Information related to loans and fees receivable measure at fair value. us-gaap_FiniteLivedIntangibleAssetsNet Total amortization expense Depreciation, amortization and accretion, net Document Fiscal Period Focus Pledging Purpose [Axis] Customer [Domain] Intangible assets - gross carrying amount Document Fiscal Year Focus Pledging Purpose [Domain] Amendment Flag Common Stock [Member] us-gaap_SubleaseIncome Sublease income Change in unrealized losses for the period included in earnings (or changes in net assets) for assets held at the end of the period Document Period End Date Issued (in shares) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross Legal Entity [Axis] us-gaap_InterestAndDividendIncomeOperating Total operating revenue and other income Total operating revenue and other income Operating lease cost, gross Net Operating lease cost Business Combination [Domain] Revolving Credit Facility, Expiring January 2032 [Member] Revolving Credit Facility, Expiring January 2032 Loans at amortized cost individually evaluated for impairment Entity File Number Loans at amortized cost collectively evaluated for impairment Entity Tax Identification Number Business Combination [Axis] Revolving Credit Facility, Expiring June 2032 [Member] Revolving Credit Facility, Expiring June 2032 us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment Balance at end of period collectively evaluated for impairment Disaggregation of Revenue [Table Text Block] Entity [Domain] Entity Central Index Key Allowance for credit losses Balance at beginning of period Balance at end of period us-gaap_FinancingReceivableAllowanceForCreditLosses Entity Registrant Name Charge-offs Software, Internally Developed [Member] Entity Current Reporting Status Entity Incorporation, State or Country Code Current Fiscal Year End Date Entity Filer Category Preferred Stock, Dividends Per Share (in dollars per share) Preferred Stock, Dividends Per Share, Declared (in dollars per share) Entity Shell Company Entity Emerging Growth Company Entity Small Business atlc_NumberOfMajorCustomers Number of Major Customers In reference to the number of major customers. atlc_DebtInstrumentVariableRate Debt Instrument, Variable Rate The variable rate used for a debt instrument. Private Label Credit Receivable [Member] In reference to receivable private label credit. Employee Stock Purchase Plan [Member] Information related to the Employee Stock Purchase Plan (the "ESPP"). Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] us-gaap_PreferredStockDividendsIncomeStatementImpact Preferred stock and preferred unit dividends and discount accretion Senior Secured Term Loan Facility [Member] Information related to a Senior Secured Term Loan Facility. Aggregate unpaid gross balance of loans carried at fair value atlc_FairValueOptionLoansAndFeesReceivableUnpaidGrossBalance This item represents the aggregate gross balance within loans and fees receivables that are reported at fair value for which the fair value option has been elected. Revolving Credit Facility, Expiring January 2028 [Member] Revolving Credit Facility, Expiring January 2028 Revolving Credit Facility, Expiring December 2028 [Member] Revolving Credit Facility Expiring December 2028 Dove Ventures, LLC [Member] Information related to Dove Ventures, LLC, a Nevada limited liability company ("Dove"). Revolving Credit Facility, Expiring November 2029 [Member] Revolving Credit Facility, Expiring November 2029 us-gaap_InterestExpense Interest expense Interest expense atlc_CommonStockAggregateOfferingPrice Common Stock Aggregate Offering Price Represents the aggregate offering price for common stock. Decrease in accrued and unpaid preferred stock and preferred unit dividends The amount of change in accrued and unpaid preferred dividends. Total revenue and other income Total revenue and other income Revenue and other income: Revolving Credit Facility, Expiring April 2029 [Member] Revolving Credit Facility, Expiring April 2029 Revolving Credit Facility, Expiring February 2030 [Member] Revolving Credit Facility, Expiring February 2030 Entity Address, State or Province Entity Address, City or Town Revolving Credit Facility, Expiring May 2031 [Member] Revolving Credit Facility, Expiring May 2031 Revolving Credit Facility, Expiring September 2029, 2 [Member] Revolving Credit Facility, Expiring September 2029, 2 Retained earnings Revolving Credit Facility, Expiring July 2030 [Member] Revolving Credit Facility, Expiring July 2030 Entity Address, Address Line One Revolving Credit Facility, Expiring January 2031 [Member] Revolving Credit Facility, Expiring January 2031 Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Revolving Credit Facility, Expiring December 2030 [Member] Revolving Credit Facility, Expiring December 2030 City Area Code Amortization period (Month) The amortization period for the debt. Local Phone Number us-gaap_PaymentsForProceedsFromOtherLoansAndLeases Investments in earning assets Entity Address, Postal Zip Code Revolving Credit Facility, Expiring July 2028 [Member] Revolving Credit Facility, Expiring July 2028 Revolving Credit Facility, Expiring December 2031 [Member] Revolving Credit Facility, Expiring December 2031 Amount of securing assets This line item represents aggregate carrying amount of receivables and other assets that provides security for structured financing notes, as of balance sheet date. Revolving Credit Facility, Expiring April 2029, 2 [Member] Revolving Credit Facility, Expiring April 2029, 2 Preferred Stock [Member] Title of 12(b) Security Preferred Units, Class [Domain] Security Exchange Name Trading Symbol Class of Stock [Axis] Loans at Amortized Cost [Member] Related to loans at amortized cost. Prime Rate [Member] Balance of loans greater than 90-days delinquent still accruing interest and fees Variable Rate [Axis] Class of Financing Receivable [Axis] Total notes payable before unamortized debt issuance costs and discounts The gross amount of Notes Payable. Variable Rate [Domain] Class of Financing Receivable [Domain] Increase (Decrease) in Fair Value of Loans and Fees Receivable Recorded at Fair Value Represents the increase (decrease) during the period in the fair value of loans and fees receivable. Entity Common Stock, Shares Outstanding Unfunded Outstanding Floor-Plan Financing Commitment [Member] Information related to unfunded outstanding floor-plan financing commitments. Earnings Per Share [Text Block] Preferred stock, no par value (in dollars per share) Unfunded Individual Credit Commitment [Member] Information related to unfunded commitments related to consumers ability to borrow up to the maximum credit limit assigned to each individual account. us-gaap_NetIncomeLossAttributableToNoncontrollingInterest Net (loss) income attributable to noncontrolling interests Net income Net income Deferred income tax expense us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements Settlements Purchases Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] atlc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPrincipalWriteOffs Changes in fair value due to current period principal charge-offs, net of recoveries Amount of principal write offs of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] Exercisable, aggregate intrinsic value Credit Protection Program [Member] Related to the credit protection program. us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1 Balance at end of period individually evaluated for impairment Revolving Credit Facility Expiring May 17, 2027 [Member] Represents the Revolving Credit Facility Expiring May 17, 2027. Consumer loans, including past due fees Consumer loans, including past due fees Other Nonoperating Income (Expense) Other non-operating income Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] atlc_StockRepurchasedAndRetiredDuringPeriodSharesCommonShares Redemption and retirement of common shares (in shares) Number of common shares that have been repurchased and retired during the period. Sale of Stock [Domain] Total Assets held by VIEs Total assets Assets Total assets Five Largest Retail Partners [Member] Represents the five largest retail partners. atlc_StockRepurchasedAndRetiredDuringPeriodValueCommonShares Redemption and retirement of common shares Equity impact of the value of common stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital). atlc_StockRepurchasedAndRetiredDuringPeriodValuePreferredShares Redemption and retirement of preferred shares and preferred units Equity impact of the value of preferred stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital). Cash and cash equivalents us-gaap_CashAndCashEquivalentsAtCarryingValue Cash and cash equivalent Other revenue Financing receivable, gross Loans at amortized cost Net income attributable to common shareholders per common share—diluted (in dollars per share) Revenue from Contract with Customer [Policy Text Block] Customer [Axis] us-gaap_UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense Unrecognized Tax Benefits, Interest on Income Taxes Expense Restricted Stock and Restricted Stock Units [Member] Related to restricted stock and restricted stock units. Provision for credit losses Provision for credit losses Provision for credit losses Amount of expense for provision for losses on loans and fees receivable recorded at net realizable value. Asset Class [Domain] atlc_BankPartnerChangeFeesFairValue Change in bank partner fees carried at fair value The amount of fees related to the change of bank partners carried at fair value. us-gaap_FinitelivedIntangibleAssetsAcquired1 Finite-Lived Intangible Assets Acquired Consolidation, Policy [Policy Text Block] Fair Value by Liability Class [Domain] The Fourth Amended 2014 Plan [Member] Information related to the Fourth Amended 2014 Plan. Cash paid for interest Bank partner fees The fair value of the bank partner fees. Intangible Asset, Finite-Lived [Table Text Block] Intangible Asset, Finite-Lived [Table] us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest Total equity Balance Balance Shareholders' Equity Revolving Credit Facility Expiring April 7, 2028 [Member] Related to Revolving Credit Facility Expiring April 7, 2028. Noncontrolling Interest [Member] us-gaap_StockholdersEquity Total shareholders’ equity attributable to Atlanticus Holdings Corporation Forfeited, weighted average grant date fair value (in dollars per share) Stock, Class of Stock [Table] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Operating lease right-of-use assets us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock Preferred stock and preferred unit dividends ecd_Rule10b51ArrTrmntdFlag Rule 10b5-1 Arrangement Terminated [Flag] ecd_Rule10b51ArrAdoptedFlag Rule 10b5-1 Arrangement Adopted [Flag] us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax Revenue from contracts with customers Commitments and contingencies (Note 10)