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LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES (Schedule for Allowance for Loan Loss Activity, by Portfolio Segment, Balances for Allowance for Credit Losses, and Loans Based on Impairment Methodology) (Details) - USD ($) $ in Thousands |  | 3 Months Ended | 9 Months Ended
--- | --- | --- | ---
Apr. 01, 2025 | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Allowance for loan losses: |  |  |  |  |
Balance, beginning of period |  | $ 315,574 | $ 158,131 | $ 178,644 | $ 132,182
Loans charged off |  | (40,440) | (2,719) | (45,905) | (11,701)
Recoveries credited to allowance |  | 1,847 | 2,053 | 4,368 | 4,378
Provision charged to operations |  | 16,054 | 3,220 | 38,125 | 18,701
Balance, end of period |  | 293,035 | 160,685 | 293,035 | 160,685
American National |  |  |  |  |
Allowance for loan losses: |  |  |  |  |
Initial ACL at acquisition |  |  | 0 |  | (3,896)
Initial Provision - non-PCD loans |  |  | 0 |  | 13,229
Sandy Spring |  |  |  |  |
Allowance for loan losses: |  |  |  |  |
Initial ACL at acquisition |  | 0 |  | (28,265) |
Initial Provision - non-PCD loans |  | 0 |  | 89,538 |
Initial ACL recognized charge offs before acquisition | $ 53,500 | 53,500 |  | 53,500 |
Measurement period adjustment |  | 19,000 |  | 19,000 |
Sandy Spring | PCD |  |  |  |  |
Allowance for loan losses: |  |  |  |  |
Initial ACL at acquisition | $ (28,265) |  |  |  |
Commercial Portfolio Segment [Member] |  |  |  |  |
Allowance for loan losses: |  |  |  |  |
Balance, beginning of period |  | 257,403 | 131,139 | 148,887 | 105,896
Loans charged off |  | (39,575) | (1,642) | (42,958) | (8,675)
Recoveries credited to allowance |  | 1,223 | 1,292 | 2,999 | 2,881
Provision charged to operations |  | 14,708 | 1,931 | 38,836 | 18,796
Balance, end of period |  | 233,759 | 132,720 | 233,759 | 132,720
Commercial Portfolio Segment [Member] | American National |  |  |  |  |
Allowance for loan losses: |  |  |  |  |
Initial ACL at acquisition |  |  | 0 |  | (2,609)
Initial Provision - non-PCD loans |  |  | 0 |  | 11,213
Commercial Portfolio Segment [Member] | Sandy Spring |  |  |  |  |
Allowance for loan losses: |  |  |  |  |
Initial ACL at acquisition |  | 0 |  | (21,255) |
Initial Provision - non-PCD loans |  | 0 |  | 64,740 |
Consumer Portfolio Segment [Member] |  |  |  |  |
Allowance for loan losses: |  |  |  |  |
Balance, beginning of period |  | 58,171 | 26,992 | 29,757 | 26,286
Loans charged off |  | (865) | (1,077) | (2,947) | (3,026)
Recoveries credited to allowance |  | 624 | 761 | 1,369 | 1,497
Provision charged to operations |  | 1,346 | 1,289 | (711) | (95)
Balance, end of period |  | 59,276 | 27,965 | 59,276 | 27,965
Consumer Portfolio Segment [Member] | American National |  |  |  |  |
Allowance for loan losses: |  |  |  |  |
Initial ACL at acquisition |  |  | 0 |  | (1,287)
Initial Provision - non-PCD loans |  |  | $ 0 |  | $ 2,016
Consumer Portfolio Segment [Member] | Sandy Spring |  |  |  |  |
Allowance for loan losses: |  |  |  |  |
Initial ACL at acquisition |  | 0 |  | (7,010) |
Initial Provision - non-PCD loans |  | $ 0 |  | $ 24,798 |

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