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SECURITIES (Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Values of Investment Securities) (Details) - USD ($) $ in Thousands | Dec. 31, 2022 | Dec. 31, 2021
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Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract] |  |
Total AFS securities | $ 3,204,361 | $ 3,448,784
Gross Unrealized Gains | 293 | 65,198
Gross Unrealized (Losses) | (462,838) | (32,332)
Total AFS securities, Estimated Fair Value | 2,741,816 | 3,481,650
U.S. government and agency securities |  |
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract] |  |
Total AFS securities | 70,196 | 73,830
Gross Unrealized Gains | 0 | 179
Gross Unrealized (Losses) | (8,253) | (160)
Total AFS securities, Estimated Fair Value | 61,943 | 73,849
Obligations of states and political subdivisions |  |
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract] |  |
Total AFS securities | 959,999 | 971,126
Gross Unrealized Gains | 137 | 39,343
Gross Unrealized (Losses) | (152,701) | (2,073)
Total AFS securities, Estimated Fair Value | 807,435 | 1,008,396
Corporate and other bonds |  |
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract] |  |
Total AFS securities | 243,979 | 150,201
Gross Unrealized Gains | 0 | 3,353
Gross Unrealized (Losses) | (17,599) | (178)
Total AFS securities, Estimated Fair Value | 226,380 | 153,376
Commercial |  |
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract] |  |
Total AFS securities | 349,598 | 468,893
Gross Unrealized Gains | 75 | 6,900
Gross Unrealized (Losses) | (43,512) | (4,636)
Total AFS securities, Estimated Fair Value | 306,161 | 471,157
Commercial | Agency |  |
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract] |  |
Total AFS securities | 250,186 | 361,806
Gross Unrealized Gains | 75 | 6,761
Gross Unrealized (Losses) | (39,268) | (4,215)
Total AFS securities, Estimated Fair Value | 210,993 | 364,352
Commercial | Non-agency |  |
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract] |  |
Total AFS securities | 99,412 | 107,087
Gross Unrealized Gains | 0 | 139
Gross Unrealized (Losses) | (4,244) | (421)
Total AFS securities, Estimated Fair Value | 95,168 | 106,805
Residential |  |
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract] |  |
Total AFS securities | 1,578,925 | 1,783,094
Gross Unrealized Gains | 81 | 15,423
Gross Unrealized (Losses) | (240,773) | (25,285)
Total AFS securities, Estimated Fair Value | 1,338,233 | 1,773,232
Residential | Agency |  |
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract] |  |
Total AFS securities | 1,510,110 | 1,691,651
Gross Unrealized Gains | 81 | 15,180
Gross Unrealized (Losses) | (233,961) | (24,337)
Total AFS securities, Estimated Fair Value | 1,276,230 | 1,682,494
Residential | Non-agency |  |
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract] |  |
Total AFS securities | 68,815 | 91,443
Gross Unrealized Gains | 0 | 243
Gross Unrealized (Losses) | (6,812) | (948)
Total AFS securities, Estimated Fair Value | 62,003 | 90,738
Other securities |  |
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract] |  |
Total AFS securities | 1,664 | 1,640
Gross Unrealized Gains | 0 | 0
Gross Unrealized (Losses) | 0 | 0
Total AFS securities, Estimated Fair Value | $ 1,664 | $ 1,640

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