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Securities (Tables) | 9 Months Ended
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Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract] |
Schedule of Amortized Cost and Fair Value of Investment Securities | The amortized cost and fair value of investment securities were as follows:
|  | September 30, 2024 |
|  | Amortized Cost |  |  | Gross Unrealized Gains |  |  | Gross Unrealized Losses |  |  | Fair Value |
|  | (Dollars in thousands) |
Available for Sale |  |  |  |  |  |  |  |  |  |  |  |
Corporate debt securities |  | $ | 14,350 |  |  | $ | 1,982 |  |  | $ | (50 | ) |  | $ | 16,282 |
Collateralized mortgage obligations |  |  | 208,902 |  |  |  | 22 |  |  |  | (2,125 | ) |  |  | 206,799 |
Mortgage-backed securities |  |  | 109,232 |  |  |  | 97 |  |  |  | (996 | ) |  |  | 108,333 |
Total |  | $ | 332,484 |  |  | $ | 2,101 |  |  | $ | (3,171 | ) |  | $ | 331,414 |
Held to Maturity |  |  |  |  |  |  |  |  |  |  |  |
U.S. Treasury securities and obligations of U.S. Government agencies |  | $ | 7,810 |  |  | $ | 17 |  |  | $ | (3 | ) |  | $ | 7,824 |
States and political subdivisions |  |  | 93,657 |  |  |  | 736 |  |  |  | (1,969 | ) |  |  | 92,424 |
Corporate debt securities |  |  | 12,000 |  |  |  | — |  |  |  | (3,600 | ) |  |  | 8,400 |
Collateralized mortgage obligations |  |  | 240,087 |  |  |  | 425 |  |  |  | (14,323 | ) |  |  | 226,189 |
Mortgage-backed securities |  |  | 10,615,788 |  |  |  | 5,721 |  |  |  | (992,286 | ) |  |  | 9,629,223 |
Total |  | $ | 10,969,342 |  |  | $ | 6,899 |  |  | $ | (1,012,181 | ) |  | $ | 9,964,060 |
|  | December 31, 2023 |
|  | Amortized Cost |  |  | Gross Unrealized Gains |  |  | Gross Unrealized Losses |  |  | Fair Value |
|  | (Dollars in thousands) |
Available for Sale |  |  |  |  |  |  |  |  |  |  |  |
Corporate debt securities |  | $ | 20,698 |  |  | $ | 1,827 |  |  | $ | (738 | ) |  | $ | 21,787 |
Collateralized mortgage obligations |  |  | 321,881 |  |  |  | 967 |  |  |  | (2,804 | ) |  |  | 320,044 |
Mortgage-backed securities |  |  | 97,779 |  |  |  | 96 |  |  |  | (1,118 | ) |  |  | 96,757 |
Total |  | $ | 440,358 |  |  | $ | 2,890 |  |  | $ | (4,660 | ) |  | $ | 438,588 |
Held to Maturity |  |  |  |  |  |  |  |  |  |  |  |
U.S. Treasury securities and obligations of U.S. Government agencies |  | $ | 7,631 |  |  | $ | — |  |  | $ | (52 | ) |  | $ | 7,579 |
States and political subdivisions |  |  | 116,497 |  |  |  | 1,864 |  |  |  | (2,306 | ) |  |  | 116,055 |
Corporate debt securities |  |  | 12,000 |  |  |  | — |  |  |  | (4,200 | ) |  |  | 7,800 |
Collateralized mortgage obligations |  |  | 263,250 |  |  |  | — |  |  |  | (20,864 | ) |  |  | 242,386 |
Mortgage-backed securities |  |  | 11,965,930 |  |  |  | 2,131 |  |  |  | (1,357,283 | ) |  |  | 10,610,778 |
Total |  | $ | 12,365,308 |  |  | $ | 3,995 |  |  | $ | (1,384,705 | ) |  | $ | 10,984,598 |
Securities in Continuous Loss Position | Securities with unrealized losses, segregated by length of time, that have been in a continuous loss position were as follows:
|  | September 30, 2024 |
|  | Less than 12 Months |  |  | 12 Months or More |  |  | Total |
|  | Estimated Fair Value |  |  | Unrealized Losses |  |  | Estimated Fair Value |  |  | Unrealized Losses |  |  | Estimated Fair Value |  |  | Unrealized Losses |
|  | (Dollars in thousands) |
Available for Sale |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Corporate debt securities |  | $ | — |  |  | $ | — |  |  | $ | 3,450 |  |  | $ | (50 | ) |  | $ | 3,450 |  |  | $ | (50 | )
Collateralized mortgage obligations |  |  | 36,514 |  |  |  | (204 | ) |  |  | 129,093 |  |  |  | (1,921 | ) |  |  | 165,607 |  |  |  | (2,125 | )
Mortgage-backed securities |  |  | 14,412 |  |  |  | (56 | ) |  |  | 90,003 |  |  |  | (940 | ) |  |  | 104,415 |  |  |  | (996 | )
Total |  | $ | 50,926 |  |  | $ | (260 | ) |  | $ | 222,546 |  |  | $ | (2,911 | ) |  | $ | 273,472 |  |  | $ | (3,171 | )
Held to Maturity |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
U.S. Treasury securities and obligations of U.S. Government agencies |  | $ | — |  |  | $ | — |  |  | $ | 1,989 |  |  | $ | (3 | ) |  | $ | 1,989 |  |  | $ | (3 | )
States and political subdivisions |  |  | 647 |  |  |  | (1 | ) |  |  | 49,214 |  |  |  | (1,968 | ) |  |  | 49,861 |  |  |  | (1,969 | )
Corporate debt securities |  |  | — |  |  |  | — |  |  |  | 8,400 |  |  |  | (3,600 | ) |  |  | 8,400 |  |  |  | (3,600 | )
Collateralized mortgage obligations |  |  | 29 |  |  |  | — |  |  |  | 196,396 |  |  |  | (14,323 | ) |  |  | 196,425 |  |  |  | (14,323 | )
Mortgage-backed securities |  |  | 1,420 |  |  |  | (12 | ) |  |  | 9,353,645 |  |  |  | (992,274 | ) |  |  | 9,355,065 |  |  |  | (992,286 | )
Total |  | $ | 2,096 |  |  | $ | (13 | ) |  | $ | 9,609,644 |  |  | $ | (1,012,168 | ) |  | $ | 9,611,740 |  |  | $ | (1,012,181 | )
|  | December 31, 2023 |
|  | Less than 12 Months |  |  | 12 Months or More |  |  | Total |
|  | Estimated Fair Value |  |  | Unrealized Losses |  |  | Estimated Fair Value |  |  | Unrealized Losses |  |  | Estimated Fair Value |  |  | Unrealized Losses |
|  | (Dollars in thousands) |
Available for Sale |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Corporate debt securities |  | $ | 7,300 |  |  | $ | (738 | ) |  | $ | — |  |  | $ | — |  |  | $ | 7,300 |  |  | $ | (738 | )
Collateralized mortgage obligations |  |  | 54,611 |  |  |  | (729 | ) |  |  | 114,758 |  |  |  | (2,075 | ) |  |  | 169,369 |  |  |  | (2,804 | )
Mortgage-backed securities |  |  | 1,154 |  |  |  | (13 | ) |  |  | 92,211 |  |  |  | (1,105 | ) |  |  | 93,365 |  |  |  | (1,118 | )
Total |  | $ | 63,065 |  |  | $ | (1,480 | ) |  | $ | 206,969 |  |  | $ | (3,180 | ) |  | $ | 270,034 |  |  | $ | (4,660 | )
Held to Maturity |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
U.S. Treasury securities and obligations of U.S. Government agencies |  | $ | 7,580 |  |  | $ | (52 | ) |  | $ | — |  |  | $ | — |  |  | $ | 7,580 |  |  | $ | (52 | )
States and political subdivisions |  |  | 23,085 |  |  |  | (79 | ) |  |  | 41,039 |  |  |  | (2,227 | ) |  |  | 64,124 |  |  |  | (2,306 | )
Corporate debt securities |  |  | — |  |  |  | — |  |  |  | 7,800 |  |  |  | (4,200 | ) |  |  | 7,800 |  |  |  | (4,200 | )
Collateralized mortgage obligations |  |  | 50,147 |  |  |  | (470 | ) |  |  | 192,205 |  |  |  | (20,394 | ) |  |  | 242,352 |  |  |  | (20,864 | )
Mortgage-backed securities |  |  | 52,853 |  |  |  | (807 | ) |  |  | 10,354,514 |  |  |  | (1,356,476 | ) |  |  | 10,407,367 |  |  |  | (1,357,283 | )
Total |  | $ | 133,665 |  |  | $ | (1,408 | ) |  | $ | 10,595,558 |  |  | $ | (1,383,297 | ) |  | $ | 10,729,223 |  |  | $ | (1,384,705 | )
Investment Securities by Contractual Maturity | The table below summarizes the amortized cost and fair value of investment securities at September 30, 2024, by contractual maturity. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations at any time with or without call or prepayment penalties.
|  | Held to Maturity |  |  | Available for Sale |
|  | Amortized Cost |  |  | Fair Value |  |  | Amortized Cost |  |  | Fair Value |
|  | (Dollars in thousands) |
Due in one year or less |  | $ | 17,607 |  |  | $ | 17,629 |  |  | $ | — |  |  | $ | — |
Due after one year through five years |  |  | 48,525 |  |  |  | 48,545 |  |  |  | — |  |  |  | — |
Due after five years through ten years |  |  | 39,826 |  |  |  | 35,711 |  |  |  | 14,350 |  |  |  | 16,282 |
Due after ten years |  |  | 7,509 |  |  |  | 6,763 |  |  |  | — |  |  |  | — |
Subtotal |  |  | 113,467 |  |  |  | 108,648 |  |  |  | 14,350 |  |  |  | 16,282 |
Mortgage-backed securities and collateralized mortgage obligations |  |  | 10,855,875 |  |  |  | 9,855,412 |  |  |  | 318,134 |  |  |  | 315,132 |
Total |  | $ | 10,969,342 |  |  | $ | 9,964,060 |  |  | $ | 332,484 |  |  | $ | 331,414 |

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