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ACQUISITIONS - Supplemental pro forma financial information (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2022
Pro Forma |  |  |
Total revenue, net of interest expense |  | $ 175,595 | $ 512,687
Net income |  | 49,016 | 141,138
Elmira Savings Bank ("Elmira") |  |  |
Pro Forma |  |  |
Acquisitions-related expenses | $ 400 | $ 400 | $ 4,700

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