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Note 3 - Debt Securities Available for Sale and Held to Maturity (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2025
Notes Tables |
Debt Securities, Available-for-sale and Held-to-maturity [Table Text Block] |
|  | At September 30, 2025 |
|  |  |  |  |  | Gross |  |  | Gross |  |  |  |  |
|  | Amortized |  |  | Unrealized |  |  | Unrealized |  |  | Fair |
|  | Cost |  |  | Gains |  |  | Losses |  |  | Value |
|  | (In thousands) |
Debt securities available for sale: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Agency residential mortgage-backed securities ("MBS") |  | $ | 203,929 |  |  | $ | 6 |  |  | $ | (11,445 | ) |  | $ | 192,490 |
Agency commercial MBS |  |  | 398,586 |  |  |  | 788 |  |  |  | (2,210 | ) |  |  | 397,164 |
Securities of U.S. Government sponsored entities |  |  | 313,025 |  |  |  | 55 |  |  |  | (7,888 | ) |  |  | 305,192 |
Obligations of states and political subdivisions |  |  | 52,418 |  |  |  | 8 |  |  |  | (573 | ) |  |  | 51,853 |
Corporate securities |  |  | 1,917,181 |  |  |  | - |  |  |  | (119,619 | ) |  |  | 1,797,562 |
Collateralized loan obligations |  |  | 562,034 |  |  |  | 512 |  |  |  | (1,483 | ) |  |  | 561,063 |
Total debt securities available for sale |  |  | 3,447,173 |  |  |  | 1,369 |  |  |  | (143,218 | ) |  |  | 3,305,324 |
Debt securities held to maturity: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Agency residential MBS |  |  | 46,433 |  |  |  | 26 |  |  |  | (2,566 | ) |  |  | 43,893 |
Obligations of states and political subdivisions |  |  | 39,528 |  |  |  | 15 |  |  |  | (45 | ) |  |  | 39,498 |
Corporate securities |  |  | 740,545 |  |  |  | 2,576 |  |  |  | (9,324 | ) |  |  | 733,797 |
Total debt securities held to maturity |  |  | 826,506 |  |  |  | 2,617 |  |  |  | (11,935 | ) |  |  | 817,188 |
Total |  | $ | 4,273,679 |  |  | $ | 3,986 |  |  | $ | (155,153 | ) |  | $ | 4,122,512 |
|  | At December 31, 2024 |
|  |  |  |  |  | Gross |  |  | Gross |  |  |  |  |
|  | Amortized |  |  | Unrealized |  |  | Unrealized |  |  | Fair |
|  | Cost |  |  | Gains |  |  | Losses |  |  | Value |
|  | (In thousands) |
Debt securities available for sale: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Agency residential MBS |  | $ | 229,050 |  |  | $ | 1 |  |  | $ | (17,991 | ) |  | $ | 211,060 |
Agency commercial MBS |  |  | 7,098 |  |  |  | - |  |  |  | (132 | ) |  |  | 6,966 |
Securities of U.S. Government sponsored entities |  |  | 311,201 |  |  |  | 1 |  |  |  | (19,085 | ) |  |  | 292,117 |
U.S. Treasury securities |  |  | 4,945 |  |  |  | 10 |  |  |  | - |  |  |  | 4,955 |
Obligations of states and political subdivisions |  |  | 63,878 |  |  |  | 9 |  |  |  | (1,701 | ) |  |  | 62,186 |
Corporate securities |  |  | 2,031,144 |  |  |  | 127 |  |  |  | (195,334 | ) |  |  | 1,835,937 |
Collateralized loan obligations |  |  | 987,155 |  |  |  | 642 |  |  |  | (5,208 | ) |  |  | 982,589 |
Total debt securities available for sale |  |  | 3,634,471 |  |  |  | 790 |  |  |  | (239,451 | ) |  |  | 3,395,810 |
Debt securities held to maturity: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Agency residential MBS |  |  | 57,927 |  |  |  | 23 |  |  |  | (4,218 | ) |  |  | 53,732 |
Obligations of states and political subdivisions |  |  | 51,261 |  |  |  | 12 |  |  |  | (377 | ) |  |  | 50,896 |
Corporate securities |  |  | 735,447 |  |  |  | - |  |  |  | (32,237 | ) |  |  | 703,210 |
Total debt securities held to maturity |  |  | 844,635 |  |  |  | 35 |  |  |  | (36,832 | ) |  |  | 807,838 |
Total |  | $ | 4,479,106 |  |  | $ | 825 |  |  | $ | (276,283 | ) |  | $ | 4,203,648 |
Investments Classified by Contractual Maturity Date [Table Text Block] |
|  | At September 30, 2025 |
|  | Debt Securities Available |  |  | Debt Securities Held |
|  | for Sale |  |  | to Maturity |
|  | Amortized |  |  | Fair |  |  | Amortized |  |  | Fair |
|  | Cost |  |  | Value |  |  | Cost |  |  | Value |
|  | (In thousands) |
Maturity in years: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
1 year or less |  | $ | 168,382 |  |  | $ | 167,424 |  |  | $ | 29,562 |  |  | $ | 29,535 |
Over 1 to 5 years |  |  | 1,234,938 |  |  |  | 1,183,538 |  |  |  | 411,838 |  |  |  | 413,990 |
Over 5 to 10 years |  |  | 879,304 |  |  |  | 803,645 |  |  |  | 338,673 |  |  |  | 329,770 |
Subtotal |  |  | 2,282,624 |  |  |  | 2,154,607 |  |  |  | 780,073 |  |  |  | 773,295 |
Collateralized loan obligations |  |  | 562,034 |  |  |  | 561,063 |  |  |  | - |  |  |  | - |
Agency residential MBS |  |  | 203,929 |  |  |  | 192,490 |  |  |  | 46,433 |  |  |  | 43,893 |
Agency commercial MBS |  |  | 398,586 |  |  |  | 397,164 |  |  |  | - |  |  |  | - |
Total |  | $ | 3,447,173 |  |  | $ | 3,305,324 |  |  | $ | 826,506 |  |  | $ | 817,188 |
|  | At December 31, 2024 |
|  | Debt Securities Available |  |  | Debt Securities Held |
|  | for Sale |  |  | to Maturity |
|  | Amortized |  |  | Fair |  |  | Amortized |  |  | Fair |
|  | Cost |  |  | Value |  |  | Cost |  |  | Value |
|  | (In thousands) |
Maturity in years: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
1 year or less |  | $ | 124,667 |  |  | $ | 124,448 |  |  | $ | 13,508 |  |  | $ | 13,468 |
Over 1 to 5 years |  |  | 993,874 |  |  |  | 940,578 |  |  |  | 347,566 |  |  |  | 342,500 |
Over 5 to 10 years |  |  | 1,292,627 |  |  |  | 1,130,169 |  |  |  | 425,634 |  |  |  | 398,138 |
Subtotal |  |  | 2,411,168 |  |  |  | 2,195,195 |  |  |  | 786,708 |  |  |  | 754,106 |
Collateralized loan obligations |  |  | 987,155 |  |  |  | 982,589 |  |  |  | - |  |  |  | - |
Agency residential MBS |  |  | 229,050 |  |  |  | 211,060 |  |  |  | 57,927 |  |  |  | 53,732 |
Agency commercial MBS |  |  | 7,098 |  |  |  | 6,966 |  |  |  | - |  |  |  | - |
Total |  | $ | 3,634,471 |  |  | $ | 3,395,810 |  |  | $ | 844,635 |  |  | $ | 807,838 |
Schedule of Unrealized Loss on Investments 1 [Table Text Block] |
|  | Debt Securities Available for Sale |
|  | At September 30, 2025 |
|  | No. of |  |  | Less than 12 months |  |  | No. of |  |  | 12 months or longer |  |  | No. of |  |  | Total |
|  | Investment |  |  |  |  |  |  | Unrealized |  |  | Investment |  |  |  |  |  |  | Unrealized |  |  | Investment |  |  |  |  |  |  | Unrealized |
|  | Positions |  |  | Fair Value |  |  | Losses |  |  | Positions |  |  | Fair Value |  |  | Losses |  |  | Positions |  |  | Fair Value |  |  | Losses |
|  | ($ in thousands) |
Agency residential MBS |  |  | 5 |  |  | $ | 18,550 |  |  | $ | (337 | ) |  |  | 104 |  |  | $ | 173,381 |  |  | $ | (11,108 | ) |  |  | 109 |  |  | $ | 191,931 |  |  | $ | (11,445 | )
Agency commercial MBS |  |  | 33 |  |  |  | 233,147 |  |  |  | (2,210 | ) |  |  | - |  |  |  | - |  |  |  | - |  |  |  | 33 |  |  |  | 233,147 |  |  |  | (2,210 | )
Securities of U.S. Government sponsored entities |  |  | - |  |  |  | - |  |  |  | - |  |  |  | 19 |  |  |  | 288,409 |  |  |  | (7,888 | ) |  |  | 19 |  |  |  | 288,409 |  |  |  | (7,888 | )
Obligations of states and political subdivisions |  |  | 1 |  |  |  | 1,311 |  |  |  | (2 | ) |  |  | 30 |  |  |  | 40,371 |  |  |  | (571 | ) |  |  | 31 |  |  |  | 41,682 |  |  |  | (573 | )
Corporate securities |  |  | - |  |  |  | - |  |  |  | - |  |  |  | 129 |  |  |  | 1,796,562 |  |  |  | (119,619 | ) |  |  | 129 |  |  |  | 1,796,562 |  |  |  | (119,619 | )
Collateralized loan obligations |  |  | 3 |  |  |  | 25,645 |  |  |  | (78 | ) |  |  | 9 |  |  |  | 84,308 |  |  |  | (1,405 | ) |  |  | 12 |  |  |  | 109,953 |  |  |  | (1,483 | )
Total |  |  | 42 |  |  | $ | 278,653 |  |  | $ | (2,627 | ) |  |  | 291 |  |  | $ | 2,383,031 |  |  | $ | (140,591 | ) |  |  | 333 |  |  | $ | 2,661,684 |  |  | $ | (143,218 | )
|  | Debt Securities Held to Maturity |
|  | At September 30, 2025 |
|  | No. of |  |  | Less than 12 months |  |  | No. of |  |  | 12 months or longer |  |  | No. of |  |  | Total |
|  | Investment |  |  |  |  |  |  | Unrecognized |  |  | Investment |  |  |  |  |  |  | Unrecognized |  |  | Investment |  |  |  |  |  |  | Unrecognized |
|  | Positions |  |  | Fair Value |  |  | Losses |  |  | Positions |  |  | Fair Value |  |  | Losses |  |  | Positions |  |  | Fair Value |  |  | Losses |
|  | ($ in thousands) |
Agency residential MBS |  |  | - |  |  | $ | - |  |  | $ | - |  |  |  | 63 |  |  | $ | 42,819 |  |  | $ | (2,566 | ) |  |  | 63 |  |  | $ | 42,819 |  |  | $ | (2,566 | )
Obligations of states and political subdivisions |  |  | 1 |  |  |  | 365 |  |  |  | - |  |  |  | 20 |  |  |  | 18,465 |  |  |  | (45 | ) |  |  | 21 |  |  |  | 18,830 |  |  |  | (45 | )
Corporate securities |  |  | 2 |  |  |  | 4,705 |  |  |  | (9 | ) |  |  | 27 |  |  |  | 373,660 |  |  |  | (9,315 | ) |  |  | 29 |  |  |  | 378,365 |  |  |  | (9,324 | )
Total |  |  | 3 |  |  | $ | 5,070 |  |  | $ | (9 | ) |  |  | 110 |  |  | $ | 434,944 |  |  | $ | (11,926 | ) |  |  | 113 |  |  | $ | 440,014 |  |  | $ | (11,935 | )
|  | Debt Securities Available for Sale |
|  | At December 31, 2024 |
|  | No. of |  |  | Less than 12 months |  |  | No. of |  |  | 12 months or longer |  |  | No. of |  |  | Total |
|  | Investment |  |  |  |  |  |  | Unrealized |  |  | Investment |  |  |  |  |  |  | Unrealized |  |  | Investment |  |  |  |  |  |  | Unrealized |
|  | Positions |  |  | Fair Value |  |  | Losses |  |  | Positions |  |  | Fair Value |  |  | Losses |  |  | Positions |  |  | Fair Value |  |  | Losses |
|  | ($ in thousands) |
Agency residential MBS |  |  | 12 |  |  | $ | 18,030 |  |  | $ | (471 | ) |  |  | 103 |  |  | $ | 192,963 |  |  | $ | (17,520 | ) |  |  | 115 |  |  | $ | 210,993 |  |  | $ | (17,991 | )
Agency commercial MBS |  |  | 2 |  |  |  | 6,966 |  |  |  | (132 | ) |  |  | - |  |  |  | - |  |  |  | - |  |  |  | 2 |  |  |  | 6,966 |  |  |  | (132 | )
Securities of U.S. Government sponsored entities |  |  | 3 |  |  |  | 12,085 |  |  |  | (53 | ) |  |  | 19 |  |  |  | 275,467 |  |  |  | (19,032 | ) |  |  | 22 |  |  |  | 287,552 |  |  |  | (19,085 | )
Obligations of states and political subdivisions |  |  | 2 |  |  |  | 2,764 |  |  |  | (21 | ) |  |  | 40 |  |  |  | 51,759 |  |  |  | (1,680 | ) |  |  | 42 |  |  |  | 54,523 |  |  |  | (1,701 | )
Corporate securities |  |  | - |  |  |  | - |  |  |  | - |  |  |  | 138 |  |  |  | 1,824,327 |  |  |  | (195,334 | ) |  |  | 138 |  |  |  | 1,824,327 |  |  |  | (195,334 | )
Collateralized loan obligations |  |  | 3 |  |  |  | 26,825 |  |  |  | (15 | ) |  |  | 32 |  |  |  | 309,249 |  |  |  | (5,193 | ) |  |  | 35 |  |  |  | 336,074 |  |  |  | (5,208 | )
Total |  |  | 22 |  |  | $ | 66,670 |  |  | $ | (692 | ) |  |  | 332 |  |  | $ | 2,653,765 |  |  | $ | (238,759 | ) |  |  | 354 |  |  | $ | 2,720,435 |  |  | $ | (239,451 | )
|  | Debt Securities Held to Maturity |
|  | At December 31, 2024 |
|  | No. of |  |  | Less than 12 months |  |  | No. of |  |  | 12 months or longer |  |  | No. of |  |  | Total |
|  | Investment |  |  |  |  |  |  | Unrecognized |  |  | Investment |  |  |  |  |  |  | Unrecognized |  |  | Investment |  |  |  |  |  |  | Unrecognized |
|  | Positions |  |  | Fair Value |  |  | Losses |  |  | Positions |  |  | Fair Value |  |  | Losses |  |  | Positions |  |  | Fair Value |  |  | Losses |
|  | ($ in thousands) |
Agency residential MBS |  |  | - |  |  | $ | - |  |  | $ | - |  |  |  | 80 |  |  | $ | 52,771 |  |  | $ | (4,218 | ) |  |  | 80 |  |  | $ | 52,771 |  |  | $ | (4,218 | )
Obligations of states and political subdivisions |  |  | 24 |  |  |  | 15,822 |  |  |  | (78 | ) |  |  | 26 |  |  |  | 25,814 |  |  |  | (299 | ) |  |  | 50 |  |  |  | 41,636 |  |  |  | (377 | )
Corporate securities |  |  | 23 |  |  |  | 251,790 |  |  |  | (4,230 | ) |  |  | 35 |  |  |  | 451,420 |  |  |  | (28,007 | ) |  |  | 58 |  |  |  | 703,210 |  |  |  | (32,237 | )
Total |  |  | 47 |  |  | $ | 267,612 |  |  | $ | (4,308 | ) |  |  | 141 |  |  | $ | 530,005 |  |  | $ | (32,524 | ) |  |  | 188 |  |  | $ | 797,617 |  |  | $ | (36,832 | )
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Table Text Block] |
|  | For the Nine Months Ended September 30, |
|  | 2025 |  |  | 2024 |
|  | (In thousands) |
Allowance for credit losses: |  |  |  |  |  |  |  |
Beginning balance |  | $ | 1 |  |  | $ | 1 |
Provision |  |  | - |  |  |  | - |
Chargeoffs |  |  | - |  |  |  | - |
Recoveries |  |  | - |  |  |  | - |
Total ending balance |  | $ | 1 |  |  | $ | 1 |
Debt Securities, Held-to-Maturity, Credit Quality Indicator [Table Text Block] |
|  | Credit Risk Profile by Credit Rating |
|  | At September 30, 2025 |
|  | AAA/AA/A |  |  | BBB+/BBB |  |  | Not Rated |  |  | Total |
|  | (In thousands) |
Agency residential MBS |  | $ | 45,984 |  |  | $ | - |  |  | $ | 449 |  |  | $ | 46,433 |
Obligations of states and political subdivisions |  |  | 39,528 |  |  |  | - |  |  |  | - |  |  |  | 39,528 |
Corporate securities |  |  | 557,363 |  |  |  | 183,182 |  |  |  | - |  |  |  | 740,545 |
Total |  | $ | 642,875 |  |  | $ | 183,182 |  |  | $ | 449 |  |  | $ | 826,506 |
Interest Income from Investments [Table Text Block] |
|  | For the Three Months |  |  | For the Nine Months |
|  | Ended September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
|  | (In thousands) |
Taxable |  | $ | 38,402 |  |  | $ | 48,699 |  |  | $ | 118,529 |  |  | $ | 154,648 |
Tax-exempt from federal income tax |  |  | 735 |  |  |  | 892 |  |  |  | 2,398 |  |  |  | 2,839 |
Total interest income from investment securities |  | $ | 39,137 |  |  | $ | 49,591 |  |  | $ | 120,927 |  |  | $ | 157,487 |

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