Basis of Presentation	9 Months Ended
Basis of Presentation	Sep. 30, 2025
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited consolidated financial statements included in this quarterly report do not include all of the information and footnotes required by U.S. Generally Accepted Accounting Principles ("GAAP") for a full year presentation and certain disclosures have been condensed or omitted in accordance with rules and regulations of the SEC. In the application of certain accounting policies, management is required to make assumptions regarding the effect of matters that are inherently uncertain. These estimates and assumptions affect the reported amounts of certain assets, liabilities, revenues, and expenses in the unaudited consolidated financial statements. Different amounts could be reported under different conditions, or if different assumptions were used in the application of these accounting policies. The accounting policy that management considers critical in this respect is the determination of the allowance for credit losses. In management’s opinion, the unaudited consolidated financial statements reflect all adjustments of a normal recurring nature. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year ended December 31, 2025. The unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024. Cash and cash equivalents in the consolidated statements of cash flow include cash and noninterest bearing balances due from banks, interest-bearing balances due from banks, and money market funds. Management regularly evaluates the credit risk associated with the counterparties to these transactions and believes that the Company is not exposed to any significant credit risk on cash and cash equivalents. The Company has evaluated subsequent events for potential recognition and/or disclosure as of the date of these unaudited consolidated financial statements, and determined that no further disclosures were required. The consolidated financial information included herein combines the results of operations, assets, liabilities, and shareholders’ equity of the Company and its subsidiaries. Amounts in the prior periods’ unaudited consolidated financial statements are reclassified when necessary to conform to the current period’s presentation. All significant intercompany balances and transactions are eliminated in consolidation. Newly Adopted Accounting Standards ASU No. 2023-07, "Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures." The amendments in this update improve financial reporting by requiring disclosure of incremental segment information on an annual and interim basis. The amendments in this ASU are effective for the Company for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024. Adoption did not have a significant effect on our financial statements or disclosures. ASU No. 2024-02, "Codification Improvements," removes all references to FASB Concepts Statements from the FASB Accounting Standards Codification to simplify the Codification. The amendments in this ASU are effective for the Company for fiscal years beginning after December 15, 2024, including interim periods within those fiscal years. Adoption did not have a significant effect on our financial statements or disclosures. Accounting Standards Pending Adoption ASU No. 2023-06, "Disclosure Improvements," amends the disclosure or presentation requirements related to various subtopics in the FASB Accounting Standards Codification. The new guidance is intended to align GAAP requirements with those of the SEC. The ASU will become effective for each amendment on the earlier of the date on which the SEC's removal of its related disclosure requirement from Regulation S-X or Regulation S-K becomes effective, or June 30, 2027. Early adoption is prohibited. Adoption of ASU 2023 - 06 is not expected to have a material impact on our consolidated financial statements. ASU No. 2023-09, "Income Taxes (Topic 740) - Improvements to Income Tax Disclosures." The amendments in this update relate to the rate reconciliation and income taxes paid disclosures to improve the transparency of income tax disclosures by requiring (1) consistent categories and greater disaggregation of information in the rate reconciliation and (2) income taxes paid disaggregated by jurisdiction. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024. Tompkins is currently evaluating the potential impact of ASU 2023-09 on our consolidated financial statements. ASU No. 2024-03, "Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses," requires new financial statement disclosures in tabular format, disaggregating information about prescribed categories underlying any relevant income statement expense captions, including employee compensation, depreciation, and intangible asset amortization. Tompkins is required to adopt this ASU prospectively for annual periods beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. Early adoption and retrospective application are permitted. The Company reviews new accounting standards as issued. Management has not identified any other new standards that it believes will have a material impact on the Company’s financial statements.