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INVESTMENT SECURITIES - Investment Securities in a Continuous Unrealized Loss Position (Details) $ in Thousands | Sep. 30, 2023 USD ($) position | Dec. 31, 2022 USD ($) position
--- | --- | ---
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions |  |
Less than 12 months | position | 350 | 1,149
12 months or longer | position | 1,267 | 430
Total | position | 1,617 | 1,579
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value |  |
Less than 12 months | $ 176,969 | $ 1,955,294
12 months or longer | 2,584,226 | 2,106,692
Total | 2,761,195 | 4,061,986
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses |  |
Less than 12 months | 12,956 | 188,107
12 months or longer | 534,249 | 336,081
Total | $ 547,205 | $ 524,188
Number of positions |  |
Less than 12 Months | position | 39 | 23
12 Months or Longer | position | 0 | 0
Total | position | 39 | 23
Fair Value |  |
Less than 12 Months | $ 990,660 | $ 1,034,795
12 Months or Longer | 0 | 0
Total | 990,660 | 1,034,795
Gross Unrealized Losses |  |
Less than 12 Months | 134,880 | 44,900
12 Months or Longer | 0 | 0
Total | 134,880 | $ 44,900
Available-for-sale, allowance for credit losses | 0 |
Accrued interest receivable on available-for-sale debt securities | $ 11,800 |
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] | Interest Receivable |
Accrued interest and fees receivable | $ 2,900 |
U.S. Treasury and agency securities |  |
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions |  |
Less than 12 months | position | 0 | 41
12 months or longer | position | 64 | 61
Total | position | 64 | 102
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value |  |
Less than 12 months | $ 0 | $ 1,384,075
12 months or longer | 1,979,439 | 1,859,462
Total | 1,979,439 | 3,243,537
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses |  |
Less than 12 months | 0 | 132,511
12 months or longer | 399,168 | 284,498
Total | $ 399,168 | $ 417,009
Number of positions |  |
Less than 12 Months | position | 23 | 23
12 Months or Longer | position | 0 | 0
Total | position | 23 | 23
Fair Value |  |
Less than 12 Months | $ 967,588 | $ 1,034,795
12 Months or Longer | 0 | 0
Total | 967,588 | 1,034,795
Gross Unrealized Losses |  |
Less than 12 Months | 134,091 | 44,900
12 Months or Longer | 0 | 0
Total | $ 134,091 | $ 44,900
Obligations of state and political subdivisions |  |
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions |  |
Less than 12 months | position | 285 | 582
12 months or longer | position | 434 | 76
Total | position | 719 | 658
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value |  |
Less than 12 months | $ 165,835 | $ 370,524
12 months or longer | 263,067 | 47,923
Total | 428,902 | 418,447
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses |  |
Less than 12 months | 12,417 | 35,488
12 months or longer | 59,976 | 9,839
Total | $ 72,393 | $ 45,327
Government agency mortgage-backed securities |  |
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions |  |
Less than 12 months | position | 65 | 497
12 months or longer | position | 727 | 274
Total | position | 792 | 771
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value |  |
Less than 12 months | $ 11,134 | $ 190,727
12 months or longer | 325,079 | 189,919
Total | 336,213 | 380,646
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses |  |
Less than 12 months | 539 | 19,508
12 months or longer | 73,479 | 40,606
Total | $ 74,018 | $ 60,114
Number of positions |  |
Less than 12 Months | position | 16 |
12 Months or Longer | position | 0 |
Total | position | 16 |
Fair Value |  |
Less than 12 Months | $ 23,072 |
12 Months or Longer | 0 |
Total | 23,072 |
Gross Unrealized Losses |  |
Less than 12 Months | 789 |
12 Months or Longer | 0 |
Total | $ 789 |
Corporate debt securities |  |
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions |  |
Less than 12 months | position | 0 | 0
12 months or longer | position | 2 | 2
Total | position | 2 | 2
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value |  |
Less than 12 months | $ 0 | $ 0
12 months or longer | 7,174 | 7,114
Total | 7,174 | 7,114
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses |  |
Less than 12 months | 0 | 0
12 months or longer | 826 | 886
Total | $ 826 | $ 886
Government agency collateralized mortgage obligations |  |
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions |  |
Less than 12 months | position | 0 | 29
12 months or longer | position | 40 | 17
Total | position | 40 | 46
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value |  |
Less than 12 months | $ 0 | $ 9,968
12 months or longer | 9,467 | 2,274
Total | 9,467 | 12,242
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses |  |
Less than 12 months | 0 | 600
12 months or longer | 800 | 252
Total | $ 800 | $ 852

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