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v3.25.2

INVESTMENT SECURITIES - Amortized cost and estimated fair value of investment securities (Details) - USD ($) $ in Thousands | 6 Months Ended | 12 Months Ended
--- | --- | ---
Jun. 30, 2025 | Dec. 31, 2024
Available-for-Sale Portfolio: |  |
Amortized Cost | $ 3,169,432 | $ 3,192,392
Gross Unrealized Gains | 338 | 325
Gross Unrealized Losses | 337,400 | 407,003
Fair Value | 2,832,370 | 2,785,714
Held-to-Maturity Portfolio: |  |
Amortized Cost | 1,430,991 | 1,345,155
Gross Unrealized Gains | 1,251 | 448
Gross Unrealized Losses | 96,167 | 125,435
Fair Value | 1,336,075 | 1,220,168
Other equity securities, at adjusted cost |  |
Equity securities, Fair values | 2,600 | 2,400
Equity securities without readily determinable fair value amount | 84,100 | 85,100
U.S. Treasury and agency securities |  |
Available-for-Sale Portfolio: |  |
Amortized Cost | 2,394,285 | 2,389,208
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | 239,341 | 305,422
Fair Value | 2,154,944 | 2,083,786
Held-to-Maturity Portfolio: |  |
Amortized Cost | 1,153,480 | 1,138,743
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | 95,300 | 123,194
Fair Value | 1,058,180 | 1,015,549
Obligations of state and political subdivisions |  |
Available-for-Sale Portfolio: |  |
Amortized Cost | 421,049 | 428,204
Gross Unrealized Gains | 272 | 288
Gross Unrealized Losses | 46,081 | 41,997
Fair Value | 375,240 | 386,495
Government agency mortgage-backed securities |  |
Available-for-Sale Portfolio: |  |
Amortized Cost | 343,413 | 360,102
Gross Unrealized Gains | 66 | 37
Gross Unrealized Losses | 51,552 | 58,915
Fair Value | 291,927 | 301,224
Held-to-Maturity Portfolio: |  |
Amortized Cost | 277,511 | 206,412
Gross Unrealized Gains | 1,251 | 448
Gross Unrealized Losses | 867 | 2,241
Fair Value | 277,895 | 204,619
Corporate debt securities |  |
Available-for-Sale Portfolio: |  |
Amortized Cost | 5,000 | 8,000
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | 171 | 303
Fair Value | 4,829 | 7,697
Government agency collateralized mortgage obligations |  |
Available-for-Sale Portfolio: |  |
Amortized Cost | 5,685 | 6,878
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | 255 | 366
Fair Value | 5,430 | 6,512
Held-to-Maturity Portfolio: |  |
Amortized Cost | 0 |
Fair Value | 0 |
Federal Home Loan Bank Common Stock |  |
Other equity securities, at adjusted cost |  |
Equity securities without readily determinable fair value amount | 44,900 | 45,400
Federal Reserve Bank Common Stock |  |
Other equity securities, at adjusted cost |  |
Equity securities without readily determinable fair value amount | 33,300 | 33,400
Other Equity Securities |  |
Other equity securities, at adjusted cost |  |
Equity securities without readily determinable fair value amount | $ 5,900 | $ 6,300

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