Note 1 - Summary of Significant Accounting Policies	3 Months Ended
Mar. 31, 2024
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	NOTE 1 - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation: BankFinancial Corporation, a Maryland corporation headquartered in Burr Ridge, Illinois, is the owner of all of the issued and outstanding capital stock of BankFinancial, National Association (the “Bank”). The interim unaudited consolidated financial statements include the accounts and transactions of BankFinancial Corporation, the Bank, and the Bank’s wholly-owned subsidiaries, Financial Assurance Services, Inc. and BFIN Asset Recovery Company, LLC (collectively, the “Company”), and reflect all normal and recurring adjustments that are, in the opinion of management, considered necessary for a fair presentation of the financial condition and results of operations for the periods presented. Such adjustments are the only adjustments reflected in the accompanying financial statements. All significant intercompany accounts and transactions have been eliminated. The results of operations for the three-month period ended March 31, 2024 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2024 or for any other period. Certain information and note disclosures normally included in financial statements prepared in conformity with accounting principles generally accepted in the United States of America (“US GAAP”) have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Use of Estimates: The preparation of the consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Although these estimates and assumptions are based on the best available information, actual information and actual results could differ from those estimates. Factored Receivables: The Company purchases invoices from its factoring customers in schedules or batches. These receivables are included in loans receivable on the Consolidated Statements of Financial Condition, and as commercial loans and leases in Note 4 - Loans Receivable. The face value of the invoices purchased or amount advanced is recorded by the Company as factored receivables, and the unadvanced portions of the invoices purchased, less fees, are considered customer reserves. The customer reserves are held to settle any payment disputes or collection shortfalls. Customer reserves may be used to pay customers’ obligations to various third parties as directed by the customer. Customer reserves are periodically released to or withdrawn by customers, and are reported as noninterest-bearing deposits in the Consolidated Statements of Financial Condition. The unpaid principal balances of these receivables were $3.5 million and $5.9 million at March 31, 2024 and December 31, 2023, respectively, and are included in commercial loans and leases. The customer reserves associated with the factored receivables were $755,000 and $2.1 million at March 31, 2024 and December 31, 2023, respectively. Factoring fees are recognized in interest income as incurred by the customer and deducted from the customer's reserve balances. Other factoring-related fees, which include wire transfer fees, broker fees, and other similar fees, are reported by the Company as loan servicing fees in noninterest income. Interest-Bearing Time Deposits in other Financial Institutions: Interest-bearing time deposits in other financial institutions are carried at cost. Prior year financial statement disclosures reported interest-bearing time deposits in other financial institutions, maturing in 90 days or more, with Securities. Reclassifications: Certain reclassifications have been made in the prior period’s financial statements to conform them to the current period’s presentation with no impact on previously reported net income or stockholders' equity. These unaudited consolidated financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, as filed with the SEC.

Note 1 - Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2024

Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]

NOTE 1 - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation: BankFinancial Corporation, a Maryland corporation headquartered in Burr Ridge, Illinois, is the owner of all of the issued and outstanding capital stock of BankFinancial, National Association (the “Bank”). The interim unaudited consolidated financial statements include the accounts and transactions of BankFinancial Corporation, the Bank, and the Bank’s wholly-owned subsidiaries, Financial Assurance Services, Inc. and BFIN Asset Recovery Company, LLC (collectively, the “Company”), and reflect all normal and recurring adjustments that are, in the opinion of management, considered necessary for a fair presentation of the financial condition and results of operations for the periods presented. Such adjustments are the only adjustments reflected in the accompanying financial statements. All significant intercompany accounts and transactions have been eliminated. The results of operations for the three-month period ended March 31, 2024 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2024 or for any other period.

Certain information and note disclosures normally included in financial statements prepared in conformity with accounting principles generally accepted in the United States of America (“US GAAP”) have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”).

Use of Estimates: The preparation of the consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Although these estimates and assumptions are based on the best available information, actual information and actual results could differ from those estimates.

Factored Receivables: The Company purchases invoices from its factoring customers in schedules or batches. These receivables are included in loans receivable on the Consolidated Statements of Financial Condition, and as commercial loans and leases in Note 4 - Loans Receivable. The face value of the invoices purchased or amount advanced is recorded by the Company as factored receivables, and the unadvanced portions of the invoices purchased, less fees, are considered customer reserves. The customer reserves are held to settle any payment disputes or collection shortfalls. Customer reserves may be used to pay customers’ obligations to various third parties as directed by the customer. Customer reserves are periodically released to or withdrawn by customers, and are reported as noninterest-bearing deposits in the Consolidated Statements of Financial Condition. The unpaid principal balances of these receivables were $3.5 million and $5.9 million at March 31, 2024 and December 31, 2023, respectively, and are included in commercial loans and leases. The customer reserves associated with the factored receivables were $755,000 and $2.1 million at March 31, 2024 and December 31, 2023, respectively.

Factoring fees are recognized in interest income as incurred by the customer and deducted from the customer's reserve balances. Other factoring-related fees, which include wire transfer fees, broker fees, and other similar fees, are reported by the Company as loan servicing fees in noninterest income.

Interest-Bearing Time Deposits in other Financial Institutions: Interest-bearing time deposits in other financial institutions are carried at cost. Prior year financial statement disclosures reported interest-bearing time deposits in other financial institutions, maturing in 90 days or more, with Securities.

Reclassifications: Certain reclassifications have been made in the prior period’s financial statements to conform them to the current period’s presentation with no impact on previously reported net income or stockholders' equity.

These unaudited consolidated financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, as filed with the SEC.