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LOANS AND ALLOWANCE FOR CREDIT LOSSES - Allowance for Credit Losses (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022 | Dec. 31, 2022
Allowance for credit loss - loans |  |  |  |  |
Beginning balance | $ 63,284 | $ 55,542 | $ 61,059 | $ 49,869 |
Charge-offs | (2,942) | (2,688) | (8,930) | (6,991) |
Recoveries | 1,693 | 2,330 | 5,464 | 5,711 |
Provision | 2,910 | 5,179 | 7,352 | 11,703 |
Ending balance | 64,945 | 60,363 | 64,945 | 60,363 |
Accrued interest receivable on loans | 28,400 |  | 28,400 |  |
Purchase of loans |  |  |  | 436,900 |
Amount pledged | 9,385,121 |  | 9,385,121 |  | $ 8,748,335
Amounts outstanding | 315,800 |  | 315,800 |  |
Sale of secondary market eligible residential consumer mortgage loans |  |  | 4,600 | 4,500 |
Liabilities for off-balance-sheet |  |  |  |  |
Beginning balance | 933 | 1,223 | 1,123 | 803 |
Charge-offs | 0 | 0 | 0 | 0 |
Recoveries | 0 | 0 | 0 | 0 |
PCD Allowance at Acquisition |  |  |  | 0 |
Provision | (32) | (118) | (222) | 302 |
Ending balance | 901 | 1,105 | 901 | 1,105 |
Allowance for credit loss |  |  |  |  |
Beginning balance | 64,217 | 56,765 | 62,182 | 50,672 |
Charge-offs | (2,942) | (2,688) | (8,930) | (6,991) |
Recoveries | 1,693 | 2,330 | 5,464 | 5,711 |
PCD Allowance at Acquisition |  |  |  | 71 |
Provision | 2,878 | 5,061 | 7,130 | 12,005 |
Ending balance | 65,846 | 61,468 | 65,846 | 61,468 |
Assets pledged as collateral | Borrowings from FHLB and FRB |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Amount pledged | 4,300,000 |  | 4,300,000 |  |
Elmira Savings Bank ("Elmira") |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Ending balance | 64,900 | 60,400 | 64,900 | 60,400 |
Commercial Loan |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Charge-offs |  |  | (618) |  |
Purchase of loans |  |  |  | 125,300 |
Consumer indirect |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Charge-offs |  |  | (6,490) |  |
Purchase of loans |  |  |  | 9,400 |
Consumer direct |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Charge-offs |  |  | (1,366) |  |
Purchase of loans |  |  |  | 12,500 |
Home equity |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Charge-offs |  |  | (90) |  |
Purchase of loans |  |  |  | 18,300 |
Consumer mortgage |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Charge-offs |  |  | (366) |  |
Purchase of loans |  |  |  | 271,400 |
Commercial Portfolio Segment | Commercial Loan |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Beginning balance | 25,291 | 23,241 | 23,297 | 22,995 |
Charge-offs | (139) | (495) | (618) | (650) |
Recoveries | 152 | 755 | 437 | 1,249 |
Provision | 740 | 430 | 2,928 | 266 |
Ending balance | 26,044 | 23,931 | 26,044 | 23,931 |
Allowance for credit loss |  |  |  |  |
PCD Allowance at Acquisition |  |  |  | 71 |
Residential Portfolio Segment | Home equity |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Beginning balance | 1,600 | 1,470 | 1,594 | 1,814 |
Charge-offs | (6) | (32) | (90) | (69) |
Recoveries | 2 | 11 | 13 | 132 |
Provision | (2) | 132 | 77 | (296) |
Ending balance | 1,594 | 1,581 | 1,594 | 1,581 |
Allowance for credit loss |  |  |  |  |
PCD Allowance at Acquisition |  |  |  | 0 |
Residential Portfolio Segment | Consumer mortgage |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Beginning balance | 14,553 | 12,631 | 14,343 | 10,017 |
Charge-offs | (143) | (113) | (366) | (230) |
Recoveries | 3 | 4 | 35 | 21 |
Provision | 558 | 1,296 | 959 | 4,010 |
Ending balance | 14,971 | 13,818 | 14,971 | 13,818 |
Allowance for credit loss |  |  |  |  |
PCD Allowance at Acquisition |  |  |  | 0 |
Consumer Portfolio Segment | Consumer indirect |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Beginning balance | 17,808 | 14,378 | 17,852 | 11,737 |
Charge-offs | (2,100) | (1,706) | (6,490) | (5,183) |
Recoveries | 1,319 | 1,386 | 4,342 | 3,732 |
Provision | 1,263 | 2,960 | 2,586 | 6,732 |
Ending balance | 18,290 | 17,018 | 18,290 | 17,018 |
Allowance for credit loss |  |  |  |  |
PCD Allowance at Acquisition |  |  |  | 0 |
Consumer Portfolio Segment | Consumer direct |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Beginning balance | 3,032 | 2,822 | 2,973 | 2,306 |
Charge-offs | (554) | (342) | (1,366) | (859) |
Recoveries | 217 | 174 | 637 | 577 |
Provision | 351 | 361 | 802 | 991 |
Ending balance | 3,046 | 3,015 | 3,046 | 3,015 |
Allowance for credit loss |  |  |  |  |
PCD Allowance at Acquisition |  |  |  | 0 |
Unallocated Financing Receivables |  |  |  |  |
Allowance for credit loss - loans |  |  |  |  |
Beginning balance | 1,000 | 1,000 | 1,000 | 1,000 |
Charge-offs | 0 | 0 | 0 | 0 |
Recoveries | 0 | 0 | 0 | 0 |
Provision | 0 | 0 | 0 | 0 |
Ending balance | $ 1,000 | $ 1,000 | $ 1,000 | 1,000 |
Allowance for credit loss |  |  |  |  |
PCD Allowance at Acquisition |  |  |  | $ 0 |

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