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INVESTMENT SECURITIES - Investment securities in a continuous unrealized loss position (Details) $ in Thousands | Sep. 30, 2024 USD ($) position | Dec. 31, 2023 USD ($)
--- | --- | ---
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value |  |
Less than 12 months | $ 19,575 | $ 72,127
12 months or longer | 2,775,680 | 2,720,541
Total | 2,795,255 | 2,792,668
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses |  |
Less than 12 months | 83 | 933
12 months or longer | 318,662 | 382,227
Total | 318,745 | 383,160
Fair Value |  |
Less than 12 Months | 61,169 | 555,836
12 Months or Longer | 1,088,812 | 522,743
Total | 1,149,981 | 1,078,579
Gross Unrealized Losses |  |
Less than 12 Months | 334 | 16,111
12 Months or Longer | 43,857 | 34,935
Total | 44,191 | 51,046
Available-for-sale, allowance for credit losses | 0 |
Accrued interest receivable on available-for-sale debt securities | $ 8,700 |
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] | Interest Receivable |
U.S. Treasury and agency securities |  |
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value |  |
Less than 12 months | $ 0 | 0
12 months or longer | 2,142,622 | 2,080,783
Total | 2,142,622 | 2,080,783
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses |  |
Less than 12 months | 0 | 0
12 months or longer | 244,022 | 300,385
Total | 244,022 | 300,385
Fair Value |  |
Less than 12 Months | 0 | 536,885
12 Months or Longer | 1,087,430 | 521,350
Total | 1,087,430 | 1,058,235
Gross Unrealized Losses |  |
Less than 12 Months | 0 | 15,953
12 Months or Longer | 43,848 | 34,913
Total | 43,848 | 50,866
Obligations of state and political subdivisions |  |
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value |  |
Less than 12 months | 19,552 | 63,541
12 months or longer | 302,843 | 287,191
Total | 322,395 | 350,732
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses |  |
Less than 12 months | 83 | 878
12 months or longer | 29,542 | 29,107
Total | 29,625 | 29,985
Government agency mortgage-backed securities |  |
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value |  |
Less than 12 months | 23 | 8,586
12 months or longer | 315,368 | 336,266
Total | 315,391 | 344,852
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses |  |
Less than 12 months | 0 | 55
12 months or longer | 44,452 | 51,557
Total | 44,452 | 51,612
Fair Value |  |
Less than 12 Months | 61,169 | 18,951
12 Months or Longer | 1,382 | 1,393
Total | 62,551 | 20,344
Gross Unrealized Losses |  |
Less than 12 Months | 334 | 158
12 Months or Longer | 9 | 22
Total | $ 343 | 180
Corporate debt securities |  |
Available-for-Sale Securities in Unrealized Loss Positions, Number of Positions |  |
Total | position | 2 |
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value |  |
Less than 12 months | $ 0 | 0
12 months or longer | 7,673 | 7,394
Total | 7,673 | 7,394
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses |  |
Less than 12 months | 0 | 0
12 months or longer | 327 | 606
Total | 327 | 606
Government agency collateralized mortgage obligations |  |
Available-for-Sale Securities, in Unrealized Loss Position, Fair Value |  |
Less than 12 months | 0 | 0
12 months or longer | 7,174 | 8,907
Total | 7,174 | 8,907
Available-for-Sale Securities, in Unrealized Loss Position, Gross Unrealized Losses |  |
Less than 12 months | 0 | 0
12 months or longer | 319 | 572
Total | $ 319 | $ 572

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