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ACQUISITIONS (Consideration Transferred) (Details) - USD ($) $ in Thousands |  | 3 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
Apr. 01, 2025 | Jun. 30, 2025 | Jun. 30, 2024 | Sep. 30, 2025 | Dec. 31, 2024 | Sep. 30, 2024
Business Acquisition [Line Items] |  |  |  |  |  |
Purchase price consideration |  | $ 1,275,247 | $ 505,746 |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract] |  |  |  |  |  |
Preliminary goodwill |  |  |  | $ 1,726,386 | $ 1,214,053 |
American National |  |  |  |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract] |  |  |  |  |  |
Total assets |  |  |  |  |  | $ 2,948,035
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract] |  |  |  |  |  |
Total liabilities |  |  |  |  |  | $ 2,730,061
Preliminary goodwill |  |  |  |  | $ 288,842 |
Sandy Spring |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Purchase price consideration | $ 1,275,969 |  |  |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract] |  |  |  |  |  |
Cash and cash equivalents | 270,211 |  |  |  |  |
Securities AFS | 1,266,925 |  |  |  |  |
Restricted Stock | 68,310 |  |  |  |  |
LHFI | 8,611,931 |  |  |  |  |
Premises and equipment | 59,402 |  |  |  |  |
Core deposit intangibles and other intangibles | 290,650 |  |  |  |  |
Bank owned life insurance | 170,482 |  |  |  |  |
Lease right of use asset | 40,808 |  |  |  |  |
Other assets | 327,088 |  |  |  |  |
Total assets | 12,974,597 |  |  | 12,974,597 |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract] |  |  |  |  |  |
Deposits | 11,227,922 |  |  |  |  |
Short-term borrowings | 272,201 |  |  |  |  |
Long-term borrowings | 560,761 |  |  |  |  |
Lease liabilities | 40,808 |  |  |  |  |
Other liabilities | 109,269 |  |  |  |  |
Total liabilities | 12,210,961 |  |  | 12,210,961 |  |
Fair value of net assets acquired | 763,636 |  |  |  |  |
Preliminary goodwill | 512,333 |  |  | $ 512,333 |  |
Sandy Spring | CRE |  |  |  |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract] |  |  |  |  |  |
LHFS | 1,839,638 |  |  |  |  |
Sandy Spring | Non-CRE |  |  |  |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract] |  |  |  |  |  |
LHFS | $ 29,152 |  |  |  |  |

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