Document and Entity Information Document Type Document Annual Report Document Period End Date Document Transition Report Entity File Number Entity Registrant Name Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Address, Address Line One Entity Address, Adress Line Two Entity Address, City or Town Entity Address State Or Province Entity Address, Postal Zip Code City Area Code Local Phone Number Title of 12(b) Security Trading Symbol Security Exchange Name Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Interactive Data Current Entity Filer Category Entity Small Business Entity Emerging Growth Company Entity Ex Transition Period ICFR Auditor Attestation Flag Document Financial Statement Error Correction [Flag] Entity Shell Company Entity Public Float Entity Common Stock, Shares Outstanding Documents Incorporated by Reference [Text Block] Entity Central Index Key Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Period Focus Amendment Flag Auditor Name Auditor Location Auditor Firm ID Combined and Condensed Consolidated Balance Sheets Statement [Table] Class of Financing Receivable [Axis] Class of Financing Receivable [Domain] Represents information pertaining to investment in receivables. Investment In Receivables [Member] Investments in receivables, net Credit Card Receivable [Member] Credit card receivables Statement [Line Items] Statement [Line Items] Assets [Abstract] Assets Cash and Cash Equivalent Cash and cash equivalents Restricted Cash Restricted cash Accounts Receivable, after Allowance for Credit Loss Accounts receivable Other Assets Other assets Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss Balance, end of period Balance, beginning of period Receivables, net Total investments in receivables, net Property, Plant and Equipment, Net Property, plant and equipment, net Other Intangible Assets, Net Other intangible assets, net Goodwill Balance at the end Balance at the beginning Goodwill Assets Total Assets Liabilities and Equity [Abstract] Liabilities and Stockholder's Equity Liabilities [Abstract] Liabilities Sum of the carrying values as of the balance sheet date of obligations incurred through that date, including liabilities incurred and payable to vendors for goods and services received, taxes, interest, rent and utilities, compensation costs, payroll taxes and fringe benefits (other than pension and post retirement obligations), contractual rights and obligations, and statutory obligations except tax liabilities. Accounts Payable and Accrued Liabilities, Excluding Tax Liabilities Accounts payable and accrued expenses Other Liabilities Other liabilities Accrued Income Taxes Current tax liabilities Deferred Income Tax Liabilities, Net Deferred tax liabilities Notes Payable Notes payable, net Notes Payable, net Outstanding balance Liabilities Total Liabilities Members' Equity [Abstract] Stockholder's Equity Common Stock, Value, Issued Common Stock par value $0.0001 per share; 330,000,000 shares and 0 shares authorized as of December 31, 2025 and December 31, 2024 and 58,298,923 and 0 shares issued and outstanding as of December 31, 2025 and December 31, 2024 Additional Paid in Capital Additional paid-in capital Retained Earnings (Accumulated Deficit) Retained earnings Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive income (loss) Equity, Attributable to Parent Ending balance Beginning balance Total stockholder's equity Liabilities and Equity Total Liabilities and Stockholder's Equity Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest Allowance for credit losses at time of acquisition Ending balance Beginning balance Allowance for credit losses Common Stock, Par or Stated Value Per Share Common Stock, par value (in dollars per share) Common Stock, Shares Authorized Common Stock, shares authorized (in shares) Common Stock, Shares, Issued Ending balance (in shares) Beginning balance (in shares) Common Stock, shares issued (in shares) Common Stock, Shares, Outstanding Common Stock, shares outstanding (in shares) Combined and Condensed Consolidated Statements of Operations and Comprehensive Income Revenues [Abstract] Revenues Amount of portfolio income. Portfolio Income Total portfolio income Amount of increase (decrease) in recoveries relating to portfolio. Increase (Decrease) In Recoveries Changes in recoveries Amount of portfolio revenue after changes in recoveries. Portfolio Revenue After Recoveries Portfolio revenue Total portfolio revenue Amount of credit card revenue. Credit Card Revenue Credit card revenue Amount of servicing revenue. Servicing Revenue Servicing revenue Revenues Total Revenues Financing Receivable, Credit Loss, Expense (Reversal) Provision for credit losses Operating Expenses [Abstract] Operating Expenses Salary and Wage, NonOfficer, Excluding Cost of Good and Service Sold Salaries and benefits Amount of expenses relating to collections and customer service expenses associated with previously charged-off receivables. Servicing Expenses Servicing expenses Depreciation, Depletion and Amortization, Nonproduction Depreciation and amortization Professional Fees Professional fees Other Selling, General and Administrative Expense Other selling, general and administrative Operating Expenses Total Operating Expenses Operating Income (Loss) Net Operating Income Net Operating Income Nonoperating Income (Expense) [Abstract] Other Income (Expense) Other Income / (Expense): Interest Expense, Nonoperating Interest expense Total Interest Expense Gain (Loss), Foreign Currency Transaction, before Tax Foreign exchange and other income (expense) Foreign exchange and other income / (expense) Nonoperating Income (Expense) Total other expense Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income Before Income Taxes Income Tax Expense (Benefit) Provision for income taxes Provision for Income Taxes Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net income Net income Net Income (Loss) Attributable to Noncontrolling Interest Net income attributable to noncontrolling interest Net Income attributable to Jefferson Capital, Inc. Net income Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Foreign currency translation gain / (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive Income Earnings Per Share Earnings per share Earnings Per Share, Basic Earnings per share, Basic (in dollars per share) Basic EPS Earnings Per Share, Diluted Earnings per share, Diluted (in dollars per share) Diluted EPS Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted average common shares outstanding Denominator Weighted Average Number of Shares Outstanding, Basic Weighted average common shares outstanding, Basic (in shares) Weighted average shares outstanding Weighted Average Number of Shares Outstanding, Diluted Weighted average common shares outstanding, Diluted (in shares) Number of shares used for diluted EPS computation Combined and Condensed Consolidated Statements of Stockholder's Equity Equity Components [Axis] Equity Component [Domain] Common Stock [Member] Common Stock Represents information pertaining to contribution by stockholder. Contribution By Stockholder [Member] Contributions by Stockholder AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) Additional Paid-in Capital [Member] Additional Paid in Capital Retained Earnings [Member] Retained Earnings Noncontrolling Interest [Member] Non-Controlling Interests Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Equity, Including Portion Attributable to Noncontrolling Interest Ending balance Beginning balance Dividends, Common Stock Dividends to stockholders APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Reorganization adjustments Stock Issued During Period, Shares, New Issues Shares issued (in shares) Stock Issued During Period, Value, New Issues Shares issued APIC, Share-Based Payment Arrangement, ESPP, Increase for Cost Recognition Stock based compensation Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Foreign currency translation Stockholders' Equity, Other Other Common Stock, Dividends, Per Share, Declared Dividends to stockholders (in dollars per share) Combined and Condensed Consolidated Statements of Cash Flows Cash Provided by (Used in) Operating Activity, Continuing Operation [Abstract] Cash flows from operating activities Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Adjustments to reconcile net income to net cash and cash equivalents provided by operating activities: Depreciation, Depletion and Amortization Depreciation and amortization Amortization of Debt Issuance Costs Amortization of debt issuance costs Amortization of note payable origination costs Accounts Receivable, Credit Loss Expense (Reversal) Provision for credit losses Share-Based Payment Arrangement, Noncash Expense Stock-based compensation Amount of increase (decrease) of deferred taxes. Increase (Decrease) in Deferred Tax Deferred income tax Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Changes in assets and liabilities: Increase (Decrease) in Other Operating Assets Other assets Increase (Decrease) in Accounts Receivable Accounts receivable Increase (Decrease) in Accounts Payable and Accrued Liabilities Accounts payable and accrued expenses Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Net cash provided by operating activities Cash Provided by (Used in) Investing Activity, Continuing Operation [Abstract] Cash flows from investing activities Payments to Acquire Finance Receivables Purchases of receivables, net Proceeds from Collection of Finance Receivables Collections applied to receivables Payments to Acquire Businesses, Net of Cash Acquired Acquisition, net of cash acquired The cash outflow (inflow) associated with the acquisition/disposal of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Purchases Of Or Proceeds From Property And Equipment, Net Purchases of property and equipment, net Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Net cash used in investing activities Cash Provided by (Used in) Financing Activity, Continuing Operation [Abstract] Cash flow from financing activities Proceeds from Notes Payable Proceeds from notes payable Repayments of Notes Payable Payments on notes payable Payments of Debt Issuance Costs Payment of debt issuance costs Debt issuance costs Payments of Dividends Dividends paid to stockholders Proceeds from Issuance of Common Stock Proceeds from issuance of common stock Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Net cash (used in) / provided by financing activities Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Exchange rate effects on cash balances held in foreign currencies Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Net (decrease) increase in cash and cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Including Discontinued Operation Cash and cash equivalents and restricted cash, end of period Cash and cash equivalents and restricted cash, beginning of period Total cash and cash equivalents and restricted cash as shown in the combined and condensed consolidated statements of cash flows Supplemental Cash Flow Information [Abstract] Supplemental cash flow disclosures Interest Paid, Including Capitalized Interest, Operating and Investing Activities Interest paid Income Taxes Paid, Net Income taxes paid Total Right-of-Use Asset Obtained in Exchange for Operating Lease Liability New leases assumed Amount of increase (decrease) in deferred tax liability in connection with reorganization Increase (Decrease) in Deferred tax liability from reorganization Deferred tax liability recognized in connection with reorganization Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation [Abstract] The following table provides a reconciliation of cash and cash equivalents and restricted cash and cash equivalents reported within the accompanying combined and condensed consolidated balance sheets that sum to the total of the same such amounts shown in the combined and condensed consolidated statements of cash flows: Summary of Significant Accounting Policies Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] Summary of Significant Accounting Policies Earnings Per Share [Text Block] Earnings Per Share Acquisitions The entire disclosure for business combination and asset acquisition. Business Combination And Asset Acquisition [Text Block] Acquisitions Fair Value Measurements Fair Value Disclosures [Text Block] Fair Value Measurements Investment in receivables, net Financing Receivables [Text Block] Investment in receivables, net No definition available. Credit Card Receivables The entire disclosure for credit card receivables. Credit Card Receivables [Text Block] Credit Card Receivables Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Goodwill and Other Intangible Assets Notes Payable, Net Debt Disclosure [Text Block] Notes Payable, Net Leases Lessee, Operating Leases [Text Block] Leases Stock Based Compensation Share-Based Payment Arrangement [Text Block] Stock Based Compensation Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Commitments and Contingencies Income taxes Income Tax Disclosure [Text Block] Income taxes Related Party Transactions Related Party Transactions Disclosure [Text Block] Related Party Transactions Segment Reporting Segment Reporting Disclosure [Text Block] Segment Reporting Subsequent Events Subsequent Events [Text Block] Subsequent Events Basis of Accounting, Policy [Policy Text Block] Basis of Presentation Foreign Currency Transactions and Translations Policy [Policy Text Block] Translation of Foreign Currencies