3.20.1 html 369 512 1 true 104 0 false 6 false false R1.htm 000 - Document - Document And Entity Information Sheet http://www.atlanticus.com/20191231/role/statement-document-and-entity-information Document And Entity Information Cover 1 false false R2.htm 001 - Statement - Consolidated Balance Sheets Sheet http://www.atlanticus.com/20191231/role/statement-consolidated-balance-sheets Consolidated Balance Sheets Statements 2 false false R3.htm 002 - Statement - Consolidated Balance Sheets (Parentheticals) Sheet http://www.atlanticus.com/20191231/role/statement-consolidated-balance-sheets-parentheticals Consolidated Balance Sheets (Parentheticals) Statements 3 false false R4.htm 003 - Statement - Consolidated Statements of Operations Sheet http://www.atlanticus.com/20191231/role/statement-consolidated-statements-of-operations Consolidated Statements of Operations Statements 4 false false R5.htm 004 - Statement - Consolidated Statements of Comprehensive Income Sheet http://www.atlanticus.com/20191231/role/statement-consolidated-statements-of-comprehensive-income Consolidated Statements of Comprehensive Income Statements 5 false false R6.htm 005 - Statement - Consolidated Statements of Shareholders' Equity (Deficit) Sheet http://www.atlanticus.com/20191231/role/statement-consolidated-statements-of-shareholders-equity-deficit Consolidated Statements of Shareholders' Equity (Deficit) Statements 6 false false R7.htm 006 - Statement - Consolidated Statements of Cash Flows Sheet http://www.atlanticus.com/20191231/role/statement-consolidated-statements-of-cash-flows Consolidated Statements of Cash Flows Statements 7 false false R8.htm 007 - Disclosure - Note 1 - Description of Our Business Sheet http://www.atlanticus.com/20191231/role/statement-note-1-description-of-our-business Note 1 - Description of Our Business Notes 8 false false R9.htm 008 - Disclosure - Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components Sheet http://www.atlanticus.com/20191231/role/statement-note-2-significant-accounting-policies-and-consolidated-financial-statement-components Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components Notes 9 false false R10.htm 009 - Disclosure - Note 3 - Segment Reporting Sheet http://www.atlanticus.com/20191231/role/statement-note-3-segment-reporting Note 3 - Segment Reporting Notes 10 false false R11.htm 010 - Disclosure - Note 4 - Shareholders' Equity and Preferred Stock Sheet http://www.atlanticus.com/20191231/role/statement-note-4-shareholders-equity-and-preferred-stock Note 4 - Shareholders' Equity and Preferred Stock Notes 11 false false R12.htm 011 - Disclosure - Note 5 - Investment in Equity-method Investee Sheet http://www.atlanticus.com/20191231/role/statement-note-5-investment-in-equitymethod-investee Note 5 - Investment in Equity-method Investee Notes 12 false false R13.htm 012 - Disclosure - Note 6 - Fair Values of Assets and Liabilities Sheet http://www.atlanticus.com/20191231/role/statement-note-6-fair-values-of-assets-and-liabilities Note 6 - Fair Values of Assets and Liabilities Notes 13 false false R14.htm 013 - Disclosure - Note 7 - Property Sheet http://www.atlanticus.com/20191231/role/statement-note-7-property Note 7 - Property Notes 14 false false R15.htm 014 - Disclosure - Note 8 - Leases Sheet http://www.atlanticus.com/20191231/role/statement-note-8-leases Note 8 - Leases Notes 15 false false R16.htm 015 - Disclosure - Note 9 - Notes Payable and Variable Interest Entities Notes http://www.atlanticus.com/20191231/role/statement-note-9-notes-payable-and-variable-interest-entities Note 9 - Notes Payable and Variable Interest Entities Notes 16 false false R17.htm 016 - Disclosure - Note 10 - Convertible Senior Notes Notes http://www.atlanticus.com/20191231/role/statement-note-10-convertible-senior-notes Note 10 - Convertible Senior Notes Notes 17 false false R18.htm 017 - Disclosure - Note 11 - Commitments and Contingencies Sheet http://www.atlanticus.com/20191231/role/statement-note-11-commitments-and-contingencies Note 11 - Commitments and Contingencies Notes 18 false false R19.htm 018 - Disclosure - Note 12 - Income Taxes Sheet http://www.atlanticus.com/20191231/role/statement-note-12-income-taxes Note 12 - Income Taxes Notes 19 false false R20.htm 019 - Disclosure - Note 13 - Net Income Attributable to Controlling Interests Per Common Share Sheet http://www.atlanticus.com/20191231/role/statement-note-13-net-income-attributable-to-controlling-interests-per-common-share Note 13 - Net Income Attributable to Controlling Interests Per Common Share Notes 20 false false R21.htm 020 - Disclosure - Note 14 - Stock-based Compensation Sheet http://www.atlanticus.com/20191231/role/statement-note-14-stockbased-compensation Note 14 - Stock-based Compensation Notes 21 false false R22.htm 021 - Disclosure - Note 15 - Employee Benefit Plans Sheet http://www.atlanticus.com/20191231/role/statement-note-15-employee-benefit-plans Note 15 - Employee Benefit Plans Notes 22 false false R23.htm 022 - Disclosure - Note 16 - Related Party Transactions Sheet http://www.atlanticus.com/20191231/role/statement-note-16-related-party-transactions Note 16 - Related Party Transactions Notes 23 false false R24.htm 023 - Disclosure - Significant Accounting Policies (Policies) Sheet http://www.atlanticus.com/20191231/role/statement-significant-accounting-policies-policies Significant Accounting Policies (Policies) Policies http://www.atlanticus.com/20191231/role/statement-note-2-significant-accounting-policies-and-consolidated-financial-statement-components 24 false false R25.htm 024 - Disclosure - Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components (Tables) Sheet http://www.atlanticus.com/20191231/role/statement-note-2-significant-accounting-policies-and-consolidated-financial-statement-components-tables Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components (Tables) Tables http://www.atlanticus.com/20191231/role/statement-note-2-significant-accounting-policies-and-consolidated-financial-statement-components 25 false false R26.htm 025 - Disclosure - Note 3 - Segment Reporting (Tables) Sheet http://www.atlanticus.com/20191231/role/statement-note-3-segment-reporting-tables Note 3 - Segment Reporting (Tables) Tables http://www.atlanticus.com/20191231/role/statement-note-3-segment-reporting 26 false false R27.htm 026 - Disclosure - Note 5 - Investment in Equity-method Investee (Tables) Sheet http://www.atlanticus.com/20191231/role/statement-note-5-investment-in-equitymethod-investee-tables Note 5 - Investment in Equity-method Investee (Tables) Tables http://www.atlanticus.com/20191231/role/statement-note-5-investment-in-equitymethod-investee 27 false false R28.htm 027 - Disclosure - Note 6 - Fair Values of Assets and Liabilities (Tables) Sheet http://www.atlanticus.com/20191231/role/statement-note-6-fair-values-of-assets-and-liabilities-tables Note 6 - Fair Values of Assets and Liabilities (Tables) Tables http://www.atlanticus.com/20191231/role/statement-note-6-fair-values-of-assets-and-liabilities 28 false false R29.htm 028 - Disclosure - Note 7 - Property (Tables) Sheet http://www.atlanticus.com/20191231/role/statement-note-7-property-tables Note 7 - Property (Tables) Tables http://www.atlanticus.com/20191231/role/statement-note-7-property 29 false false R30.htm 029 - Disclosure - Note 8 - Leases (Tables) Sheet http://www.atlanticus.com/20191231/role/statement-note-8-leases-tables Note 8 - Leases (Tables) Tables http://www.atlanticus.com/20191231/role/statement-note-8-leases 30 false false R31.htm 030 - Disclosure - Note 9 - Notes Payable and Variable Interest Entities (Tables) Notes http://www.atlanticus.com/20191231/role/statement-note-9-notes-payable-and-variable-interest-entities-tables Note 9 - Notes Payable and Variable Interest Entities (Tables) Tables http://www.atlanticus.com/20191231/role/statement-note-9-notes-payable-and-variable-interest-entities 31 false false R32.htm 031 - Disclosure - Note 10 - Convertible Senior Notes (Tables) Notes http://www.atlanticus.com/20191231/role/statement-note-10-convertible-senior-notes-tables Note 10 - Convertible Senior Notes (Tables) Tables http://www.atlanticus.com/20191231/role/statement-note-10-convertible-senior-notes 32 false false R33.htm 032 - Disclosure - Note 12 - Income Taxes (Tables) Sheet http://www.atlanticus.com/20191231/role/statement-note-12-income-taxes-tables Note 12 - Income Taxes (Tables) Tables http://www.atlanticus.com/20191231/role/statement-note-12-income-taxes 33 false false R34.htm 033 - Disclosure - Note 13 - Net Income Attributable to Controlling Interests Per Common Share (Tables) Sheet http://www.atlanticus.com/20191231/role/statement-note-13-net-income-attributable-to-controlling-interests-per-common-share-tables Note 13 - Net Income Attributable to Controlling Interests Per Common Share (Tables) Tables http://www.atlanticus.com/20191231/role/statement-note-13-net-income-attributable-to-controlling-interests-per-common-share 34 false false R35.htm 034 - Disclosure - Note 14 - Stock-based Compensation (Tables) Sheet http://www.atlanticus.com/20191231/role/statement-note-14-stockbased-compensation-tables Note 14 - Stock-based Compensation (Tables) Tables http://www.atlanticus.com/20191231/role/statement-note-14-stockbased-compensation 35 false false R36.htm 035 - Disclosure - Note 1 - Description of Our Business (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-1-description-of-our-business-details-textual Note 1 - Description of Our Business (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-1-description-of-our-business 36 false false R37.htm 036 - Disclosure - Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-2-significant-accounting-policies-and-consolidated-financial-statement-components-details-textual Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-2-significant-accounting-policies-and-consolidated-financial-statement-components-tables 37 false false R38.htm 037 - Disclosure - Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components - Summary of Allowance for Uncollectible Loans and Fees Receivable (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-2-significant-accounting-policies-and-consolidated-financial-statement-components-summary-of-allowance-for-uncollectible-loans-and-fees-receivable-details Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components - Summary of Allowance for Uncollectible Loans and Fees Receivable (Details) Details 38 false false R39.htm 038 - Disclosure - Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components - Summary of Aging of Delinquent Loans and Fees Receivable (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-2-significant-accounting-policies-and-consolidated-financial-statement-components-summary-of-aging-of-delinquent-loans-and-fees-receivable-details Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components - Summary of Aging of Delinquent Loans and Fees Receivable (Details) Details 39 false false R40.htm 039 - Disclosure - Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components - Summary of Troubled Debt Restructurings (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-2-significant-accounting-policies-and-consolidated-financial-statement-components-summary-of-troubled-debt-restructurings-details Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components - Summary of Troubled Debt Restructurings (Details) Details 40 false false R41.htm 040 - Disclosure - Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components - Summary of Fees and Related Income on Earning Assets (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-2-significant-accounting-policies-and-consolidated-financial-statement-components-summary-of-fees-and-related-income-on-earning-assets-details Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components - Summary of Fees and Related Income on Earning Assets (Details) Details 41 false false R42.htm 041 - Disclosure - Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components - Components of Revenue from Contracts with Customers (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-2-significant-accounting-policies-and-consolidated-financial-statement-components-components-of-revenue-from-contracts-with-customers-details Note 2 - Significant Accounting Policies and Consolidated Financial Statement Components - Components of Revenue from Contracts with Customers (Details) Details 42 false false R43.htm 042 - Disclosure - Note 3 - Segment Reporting (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-3-segment-reporting-details-textual Note 3 - Segment Reporting (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-3-segment-reporting-tables 43 false false R44.htm 043 - Disclosure - Note 3 - Segment Reporting - Summary of Operating Segment Information (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-3-segment-reporting-summary-of-operating-segment-information-details Note 3 - Segment Reporting - Summary of Operating Segment Information (Details) Details 44 false false R45.htm 044 - Disclosure - Note 4 - Shareholders' Equity and Preferred Stock (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-4-shareholders-equity-and-preferred-stock-details-textual Note 4 - Shareholders' Equity and Preferred Stock (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-4-shareholders-equity-and-preferred-stock 45 false false R46.htm 045 - Disclosure - Note 5 - Investment in Equity-method Investee (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-5-investment-in-equitymethod-investee-details-textual Note 5 - Investment in Equity-method Investee (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-5-investment-in-equitymethod-investee-tables 46 false false R47.htm 046 - Disclosure - Note 5 - Investment in Equity-method Investee - Summary of Equity-method Investee (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-5-investment-in-equitymethod-investee-summary-of-equitymethod-investee-details Note 5 - Investment in Equity-method Investee - Summary of Equity-method Investee (Details) Details 47 false false R48.htm 047 - Disclosure - Note 6 - Fair Values of Assets and Liabilities (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-6-fair-values-of-assets-and-liabilities-details-textual Note 6 - Fair Values of Assets and Liabilities (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-6-fair-values-of-assets-and-liabilities-tables 48 false false R49.htm 048 - Disclosure - Note 6 - Fair Values of Assets and Liabilities - Summary of Fair Value Hierarchy for Assets (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-6-fair-values-of-assets-and-liabilities-summary-of-fair-value-hierarchy-for-assets-details Note 6 - Fair Values of Assets and Liabilities - Summary of Fair Value Hierarchy for Assets (Details) Details 49 false false R50.htm 049 - Disclosure - Note 6 - Fair Values of Assets and Liabilities - Reconciliation of Level 3 Assets (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-6-fair-values-of-assets-and-liabilities-reconciliation-of-level-3-assets-details Note 6 - Fair Values of Assets and Liabilities - Reconciliation of Level 3 Assets (Details) Details 50 false false R51.htm 050 - Disclosure - Note 6 - Fair Values of Assets and Liabilities - Quantitative Information about Level 3 Assets and Liabilities Fair Value Measurements (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-6-fair-values-of-assets-and-liabilities-quantitative-information-about-level-3-assets-and-liabilities-fair-value-measurements-details Note 6 - Fair Values of Assets and Liabilities - Quantitative Information about Level 3 Assets and Liabilities Fair Value Measurements (Details) Details 51 false false R52.htm 051 - Disclosure - Note 6 - Fair Values of Assets and Liabilities - Summary of Fair Value Hierarchy for Liabilities (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-6-fair-values-of-assets-and-liabilities-summary-of-fair-value-hierarchy-for-liabilities-details Note 6 - Fair Values of Assets and Liabilities - Summary of Fair Value Hierarchy for Liabilities (Details) Details 52 false false R53.htm 052 - Disclosure - Note 6 - Fair Values of Assets and Liabilities - Reconciliation of Level 3 Liabilities (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-6-fair-values-of-assets-and-liabilities-reconciliation-of-level-3-liabilities-details Note 6 - Fair Values of Assets and Liabilities - Reconciliation of Level 3 Liabilities (Details) Details 53 false false R54.htm 053 - Disclosure - Note 6 - Fair Values of Assets and Liabilities - Summary of Other Relevant Data (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-6-fair-values-of-assets-and-liabilities-summary-of-other-relevant-data-details Note 6 - Fair Values of Assets and Liabilities - Summary of Other Relevant Data (Details) Details 54 false false R55.htm 054 - Disclosure - Note 7 - Property (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-7-property-details-textual Note 7 - Property (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-7-property-tables 55 false false R56.htm 055 - Disclosure - Note 7 - Property - Schedule of Property (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-7-property-schedule-of-property-details Note 7 - Property - Schedule of Property (Details) Details 56 false false R57.htm 056 - Disclosure - Note 8 - Leases (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-8-leases-details-textual Note 8 - Leases (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-8-leases-tables 57 false false R58.htm 057 - Disclosure - Note 8 - Leases - Lease Cost (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-8-leases-lease-cost-details Note 8 - Leases - Lease Cost (Details) Details 58 false false R59.htm 058 - Disclosure - Note 8 - Leases - Maturities of Lease Liabilities (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-8-leases-maturities-of-lease-liabilities-details Note 8 - Leases - Maturities of Lease Liabilities (Details) Details 59 false false R60.htm 059 - Disclosure - Note 9 - Notes Payable and Variable Interest Entities (Details Textual) Notes http://www.atlanticus.com/20191231/role/statement-note-9-notes-payable-and-variable-interest-entities-details-textual Note 9 - Notes Payable and Variable Interest Entities (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-9-notes-payable-and-variable-interest-entities-tables 60 false false R61.htm 060 - Disclosure - Note 9 - Notes Payable and Variable Interest Entities - Summary of Variable Interest Entities (Details) Notes http://www.atlanticus.com/20191231/role/statement-note-9-notes-payable-and-variable-interest-entities-summary-of-variable-interest-entities-details Note 9 - Notes Payable and Variable Interest Entities - Summary of Variable Interest Entities (Details) Details 61 false false R62.htm 061 - Disclosure - Note 9 - Notes Payable and Variable Interest Entities - Schedule of Structured Financing Notes Payable (Details) Notes http://www.atlanticus.com/20191231/role/statement-note-9-notes-payable-and-variable-interest-entities-schedule-of-structured-financing-notes-payable-details Note 9 - Notes Payable and Variable Interest Entities - Schedule of Structured Financing Notes Payable (Details) Details 62 false false R63.htm 062 - Disclosure - Note 9 - Notes Payable and Variable Interest Entities - Schedule of Structured Financing Notes Payable (Details) (Parentheticals) Notes http://www.atlanticus.com/20191231/role/statement-note-9-notes-payable-and-variable-interest-entities-schedule-of-structured-financing-notes-payable-details-parentheticals Note 9 - Notes Payable and Variable Interest Entities - Schedule of Structured Financing Notes Payable (Details) (Parentheticals) Details 63 false false R64.htm 063 - Disclosure - Note 9 - Notes Payable and Variable Interest Entities - Schedule of Notes Payable at Face Value and Notes Payable to Related Parties (Details) Notes http://www.atlanticus.com/20191231/role/statement-note-9-notes-payable-and-variable-interest-entities-schedule-of-notes-payable-at-face-value-and-notes-payable-to-related-parties-details Note 9 - Notes Payable and Variable Interest Entities - Schedule of Notes Payable at Face Value and Notes Payable to Related Parties (Details) Details 64 false false R65.htm 064 - Disclosure - Note 9 - Notes Payable and Variable Interest Entities - Schedule of Notes Payable at Face Value and Notes Payable to Related Parties (Details) (Parentheticals) Notes http://www.atlanticus.com/20191231/role/statement-note-9-notes-payable-and-variable-interest-entities-schedule-of-notes-payable-at-face-value-and-notes-payable-to-related-parties-details-parentheticals Note 9 - Notes Payable and Variable Interest Entities - Schedule of Notes Payable at Face Value and Notes Payable to Related Parties (Details) (Parentheticals) Details 65 false false R66.htm 065 - Disclosure - Note 10 - Convertible Senior Notes (Details Textual) Notes http://www.atlanticus.com/20191231/role/statement-note-10-convertible-senior-notes-details-textual Note 10 - Convertible Senior Notes (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-10-convertible-senior-notes-tables 66 false false R67.htm 066 - Disclosure - Note 10 - Convertible Senior Notes - Summary of Convertible Senior Notes (Details) Notes http://www.atlanticus.com/20191231/role/statement-note-10-convertible-senior-notes-summary-of-convertible-senior-notes-details Note 10 - Convertible Senior Notes - Summary of Convertible Senior Notes (Details) Details 67 false false R68.htm 067 - Disclosure - Note 11 - Commitments and Contingencies (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-11-commitments-and-contingencies-details-textual Note 11 - Commitments and Contingencies (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-11-commitments-and-contingencies 68 false false R69.htm 068 - Disclosure - Note 12 - Income Taxes (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-12-income-taxes-details-textual Note 12 - Income Taxes (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-12-income-taxes-tables 69 false false R70.htm 069 - Disclosure - Note 12 - Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-12-income-taxes-schedule-of-components-of-income-tax-expense-benefit-details Note 12 - Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Details) Details 70 false false R71.htm 070 - Disclosure - Note 12 - Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-12-income-taxes-schedule-of-effective-income-tax-rate-reconciliation-details Note 12 - Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) Details 71 false false R72.htm 071 - Disclosure - Note 12 - Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-12-income-taxes-schedule-of-deferred-tax-assets-and-liabilities-details Note 12 - Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) Details 72 false false R73.htm 072 - Disclosure - Note 12 - Income Taxes - Unrecognized Tax Benefits Rollforward (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-12-income-taxes-unrecognized-tax-benefits-rollforward-details Note 12 - Income Taxes - Unrecognized Tax Benefits Rollforward (Details) Details 73 false false R74.htm 073 - Disclosure - Note 13 - Net Income Attributable to Controlling Interests Per Common Share (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-13-net-income-attributable-to-controlling-interests-per-common-share-details-textual Note 13 - Net Income Attributable to Controlling Interests Per Common Share (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-13-net-income-attributable-to-controlling-interests-per-common-share-tables 74 false false R75.htm 074 - Disclosure - Note 13 - Net Income Attributable to Controlling Interests Per Common Share - Summary of Earning Per Share (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-13-net-income-attributable-to-controlling-interests-per-common-share-summary-of-earning-per-share-details Note 13 - Net Income Attributable to Controlling Interests Per Common Share - Summary of Earning Per Share (Details) Details 75 false false R76.htm 075 - Disclosure - Note 14 - Stock-based Compensation (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-14-stockbased-compensation-details-textual Note 14 - Stock-based Compensation (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-14-stockbased-compensation-tables 76 false false R77.htm 076 - Disclosure - Note 14 - Stock-based Compensation - Summary of Outstanding Options (Details) Sheet http://www.atlanticus.com/20191231/role/statement-note-14-stockbased-compensation-summary-of-outstanding-options-details Note 14 - Stock-based Compensation - Summary of Outstanding Options (Details) Details 77 false false R78.htm 077 - Disclosure - Note 15 - Employee Benefit Plans (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-15-employee-benefit-plans-details-textual Note 15 - Employee Benefit Plans (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-15-employee-benefit-plans 78 false false R79.htm 078 - Disclosure - Note 16 - Related Party Transactions (Details Textual) Sheet http://www.atlanticus.com/20191231/role/statement-note-16-related-party-transactions-details-textual Note 16 - Related Party Transactions (Details Textual) Details http://www.atlanticus.com/20191231/role/statement-note-16-related-party-transactions 79 false false All Reports Book All Reports atlc-20191231.xml atlc-20191231.xsd atlc-20191231_cal.xml atlc-20191231_def.xml atlc-20191231_lab.xml atlc-20191231_pre.xml http://fasb.org/us-gaap/2019-01-31 http://xbrl.sec.gov/dei/2019-01-31 http://fasb.org/srt/2019-01-31 true true