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PORTFOLIO LOANS - Schedule of Distribution of Portfolio Loans (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Jun. 30, 2025 | Dec. 31, 2024 | Sep. 30, 2024 | Jun. 30, 2024 | Dec. 31, 2023
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Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |
Total portfolio loans | $ 13,598,266 |  | $ 7,697,087 |  |  |
ACL | (174,181) | $ (183,334) | (83,404) | $ (84,981) | $ (85,226) | $ (91,740)
Portfolio loans, net | 13,424,085 |  | 7,613,683 |  |  |
Commercial loans |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |
Total portfolio loans | 10,919,490 |  | 5,552,288 |  |  |
Commercial loans | C&I and other commercial |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |
Total portfolio loans | 4,395,871 |  | 1,904,515 |  |  |
ACL | (59,436) | (68,578) | (21,589) | (21,009) | (20,286) | (21,256)
Commercial loans | CRE |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |
Total portfolio loans | 5,424,095 |  | 3,269,564 |  |  |
ACL | (70,844) | (70,935) | (32,301) | (33,735) | (35,104) | (35,465)
Commercial loans | Real estate construction |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |
Total portfolio loans | 1,099,524 |  | 378,209 |  |  |
ACL | (12,193) | (13,072) | (3,345) | (3,771) | (3,722) | (5,163)
Retail loans |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |
Total portfolio loans | 2,678,776 |  | 2,144,799 |  |  |
Retail loans | CRE |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |
Total portfolio loans | 2,196,246 |  | 1,696,457 |  |  |
ACL | (29,843) | (29,042) | (23,711) | (23,979) | (23,729) | (26,298)
Retail loans | Retail other |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |
Total portfolio loans | 482,530 |  | 448,342 |  |  |
ACL | $ (1,865) | $ (1,707) | $ (2,458) | $ (2,487) | $ (2,385) | $ (3,558)

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