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INVESTMENT SECURITIES - Amortized Cost of Investment Securities Held to Maturity (Details) - USD ($) $ in Thousands | Mar. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | $ 2,048,877 | $ 2,074,465
Aaa |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 1,088,307 | 1,107,845
Aa1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 149,926 | 148,923
Aa2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 183,052 | 184,341
Aa3 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 185,117 | 185,166
A1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 65,659 | 65,665
A2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 20,321 | 20,317
Non-rated |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 356,495 | 362,208
U.S. Government-sponsored agency securities |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 341,245 | 345,531
U.S. Government-sponsored agency securities | Aaa |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 341,245 | 345,531
U.S. Government-sponsored agency securities | Aa1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
U.S. Government-sponsored agency securities | Aa2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
U.S. Government-sponsored agency securities | Aa3 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
U.S. Government-sponsored agency securities | A1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
U.S. Government-sponsored agency securities | A2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
U.S. Government-sponsored agency securities | Non-rated |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
State and municipal |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 1,079,688 | 1,085,921
State and municipal | Aaa |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 120,618 | 120,801
State and municipal | Aa1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 149,926 | 148,923
State and municipal | Aa2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 183,052 | 184,341
State and municipal | Aa3 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 185,117 | 185,166
State and municipal | A1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 65,659 | 65,665
State and municipal | A2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 20,321 | 20,317
State and municipal | Non-rated |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 354,995 | 360,708
U.S. Government-sponsored mortgage-backed securities |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 626,444 | 641,513
U.S. Government-sponsored mortgage-backed securities | Aaa |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 626,444 | 641,513
U.S. Government-sponsored mortgage-backed securities | Aa1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
U.S. Government-sponsored mortgage-backed securities | Aa2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
U.S. Government-sponsored mortgage-backed securities | Aa3 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
U.S. Government-sponsored mortgage-backed securities | A1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
U.S. Government-sponsored mortgage-backed securities | A2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
U.S. Government-sponsored mortgage-backed securities | Non-rated |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
Foreign investment |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 1,500 | 1,500
Foreign investment | Aaa |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
Foreign investment | Aa1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
Foreign investment | Aa2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
Foreign investment | Aa3 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
Foreign investment | A1 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
Foreign investment | A2 |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | 0 | 0
Foreign investment | Non-rated |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Total | $ 1,500 | $ 1,500

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