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Note 3 - Debt Securities Available for Sale and Held to Maturity &#8211; Schedule of Estimated Market Value of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Investment securities available for sale, amortized cost, 1 year or less | $ 168,382 | $ 124,667
Investment securities available for sale, fair value, 1 year or less | 167,424 | 124,448
Investment securities held to maturity, amortized cost, 1 year or less | 29,562 | 13,508
Investment securities held to maturity, fair value, 1 year or less | 29,535 | 13,468
Investment securities available for sale, amortized cost, over 1 to 5 years | 1,234,938 | 993,874
Investment securities available for sale, fair value, over 1 to 5 years | 1,183,538 | 940,578
Investment securities held to maturity, amortized cost, over 1 to 5 years | 411,838 | 347,566
Investment securities held to maturity, fair value, over 1 to 5 years | 413,990 | 342,500
Investment securities available for sale, amortized cost, over 5 to 10 years | 879,304 | 1,292,627
Investment securities available for sale, fair value, over 5 to 10 years | 803,645 | 1,130,169
Investment securities held to maturity, amortized cost, over 5 to 10 years | 338,673 | 425,634
Investment securities held to maturity, fair value, over 5 to 10 years | 329,770 | 398,138
Investment securities available for sale, amortized cost, subtotal | 2,282,624 | 2,411,168
Investment securities available for sale, fair value, subtotal | 2,154,607 | 2,195,195
Investment securities held to maturity, amortized cost, subtotal | 780,073 | 786,708
Investment securities held to maturity, fair value, subtotal | 773,295 | 754,106
Debt securities available for sale, amortized cost | 3,447,173 | 3,634,471
Debt securities available for sale | 3,305,324 | 3,395,810
Debt securities held to maturity, amortized cost | 826,506 | 844,635
Deb Securities, Held-to-maturity, Excluding Accrued Interest, Fair Value | 817,188 | 807,838
Collateralized Debt Obligations [Member] |  |
Debt securities available for sale, amortized cost, without single date maturity | 562,034 | 987,155
Debt securities available for sale, without single date maturity | 561,063 | 982,589
Debt securities held to maturity, amortized cost, without single date maturity | 0 | 0
Debt securities held to maturity, fair value, without single date maturity | 0 | 0
Debt securities available for sale, amortized cost | 562,034 | 987,155
Debt securities available for sale | 561,063 | 982,589
Agency Residential MBS [Member] |  |
Debt securities available for sale, amortized cost, without single date maturity | 203,929 | 229,050
Debt securities available for sale, without single date maturity | 192,490 | 211,060
Debt securities held to maturity, amortized cost, without single date maturity | 46,433 | 57,927
Debt securities held to maturity, fair value, without single date maturity | 43,893 | 53,732
Debt securities available for sale, amortized cost | 203,929 | 229,050
Debt securities available for sale | 192,490 | 211,060
Debt securities held to maturity, amortized cost | 46,433 | 57,927
Deb Securities, Held-to-maturity, Excluding Accrued Interest, Fair Value | 43,893 | 53,732
Agency Commercial MBS [Member] |  |
Debt securities available for sale, amortized cost, without single date maturity | 398,586 | 7,098
Debt securities available for sale, without single date maturity | 397,164 | 6,966
Debt securities held to maturity, amortized cost, without single date maturity | 0 | 0
Debt securities held to maturity, fair value, without single date maturity | 0 | 0
Debt securities available for sale, amortized cost | 398,586 | 7,098
Debt securities available for sale | $ 397,164 | $ 6,966

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