Financial Statement Presentation	3 Months Ended
Mar. 31, 2025
Financial Statement Presentation [Abstract]
Financial Statement Presentation	(1) Financial Statement Presentation The unaudited Consolidated Interim Financial Statements of TrustCo Bank Corp NY (the “Company” or “TrustCo”) include the accounts of the Company’s subsidiary, Trustco Bank (also referred to as the “Bank”) and other subsidiaries after elimination of all significant intercompany accounts and transactions. Prior period amounts are reclassified when necessary to conform to the current period presentation. The net income reported for the three months ended March 31, 2025 is not necessarily indicative of the results that may be expected for the year ending December 31, 2025, or any interim periods. These financial statements consider events that occurred through the date of filing. In the opinion of the management of the Company, the accompanying unaudited Consolidated Interim Financial Statements contain all recurring adjustments necessary to present fairly the financial position as of March 31, 2025, the results of operations and cash flows for the three months ended March 31, 2025 and 2024. The accompanying unaudited Consolidated Interim Financial Statements should be read in conjunction with the Company’s year‑end Consolidated Financial Statements, including notes thereto, which are included in the Company’s Annual Report on Form 10‑K for the year ended December 31, 2024. The accompanying unaudited Consolidated Interim Financial Statements have been prepared in accordance with the applicable rules of the Securities and Exchange Commission (the “SEC”) and, therefore, do not include all information and notes necessary for a complete presentation of financial position, results of operations and cash flow activity required in accordance with accounting principles generally accepted in the United States. Results of operations for the three months ended March 31, 2025 are not necessarily indicative of the results that may be expected for the year ending December 31, 2025. The accounting policies of the Company, as applied in the Consolidated Interim Financial Statements presented herein, are substantially the same as those followed on an annual basis in the Annual Report on Form 10-K for the year ended December 31, 2024 filed with the SEC on March 14, 2025.

Financial Statement Presentation

3 Months Ended

Mar. 31, 2025

Financial Statement Presentation [Abstract]

(1) Financial Statement Presentation

The unaudited Consolidated Interim Financial Statements of TrustCo Bank Corp NY (the “Company” or “TrustCo”) include the accounts of the Company’s subsidiary, Trustco Bank (also referred to as the “Bank”) and other subsidiaries after elimination of all significant intercompany accounts and transactions. Prior period amounts are reclassified when necessary to conform to the current period presentation. The net income reported for the three months ended March 31, 2025 is not necessarily indicative of the results that may be expected for the year ending December 31, 2025, or any interim periods. These financial statements consider events that occurred through the date of filing.

In the opinion of the management of the Company, the accompanying unaudited Consolidated Interim Financial Statements contain all recurring adjustments necessary to present fairly the financial position as of March 31, 2025, the results of operations and cash flows for the three months ended March 31, 2025 and 2024. The accompanying unaudited Consolidated Interim Financial Statements should be read in conjunction with the Company’s year‑end Consolidated Financial Statements, including notes thereto, which are included in the Company’s Annual Report on Form 10‑K for the year ended December 31, 2024. The accompanying unaudited Consolidated Interim Financial Statements have been prepared in accordance with the applicable rules of the Securities and Exchange Commission (the “SEC”) and, therefore, do not include all information and notes necessary for a complete presentation of financial position, results of operations and cash flow activity required in accordance with accounting principles generally accepted in the United States. Results of operations for the three months ended March 31, 2025 are not necessarily indicative of the results that may be expected for the year ending December 31, 2025.

The accounting policies of the Company, as applied in the Consolidated Interim Financial Statements presented herein, are substantially the same as those followed on an annual basis in the Annual Report on Form 10-K for the year ended December 31, 2024 filed with the SEC on March 14, 2025.