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Note 3 - Investment Securities - Gross Unrealized Losses, Investment Securities Portfolio (Details) $ in Thousands | Jun. 30, 2025 USD ($) | Dec. 31, 2024 USD ($)
--- | --- | ---
Available for sale securities, less than 12 months, number of investment positions | 28 | 22
Held to Maturity securities, less than 12 months, number of investment positions | 21 | 47
Available for sale securities, less than 12 months, fair value | $ 149,425 | $ 66,670
Held to Maturity securities, less than 12 months, fair value | 59,597 | 267,612
Available for sale securities, less than 12 months, unrealized loss | (822) | (692)
Held to Maturity securities, less than 12 months, unrealized loss | $ (242) | $ (4,308)
Available for sale securities, 12 months or longer, number of investment positions | 314 | 332
Held to Maturity securities, 12 months or longer, number of investment positions | 127 | 141
Available for sale securities, 12 months or longer, fair value | $ 2,491,049 | $ 2,653,765
Held to Maturity securities, 12 months or longer, fair value | 521,651 | 530,005
Available for sale securities, 12 months or longer, unrealized loss | (165,711) | (238,759)
Held to Maturity securities, 12 months or longer, unrealized loss | $ (17,672) | $ (32,524)
Available for sale securities, total, number of investment positions | 342 | 354
Held to Maturity securities, total, number of investment positions | 148 | 188
Available for sale securities, total, fair value | $ 2,640,474 | $ 2,720,435
Held to Maturity securities, total, fair value | 581,248 | 797,617
Available for sale securities, total, unrealized loss | (166,533) | (239,451)
Held to Maturity securities, total, unrealized loss | $ (17,914) | $ (36,832)
Agency Residential MBS [Member] |  |
Available for sale securities, less than 12 months, number of investment positions | 9 | 12
Held to Maturity securities, less than 12 months, number of investment positions | 0 | 0
Available for sale securities, less than 12 months, fair value | $ 17,873 | $ 18,030
Held to Maturity securities, less than 12 months, fair value | 0 | 0
Available for sale securities, less than 12 months, unrealized loss | (549) | (471)
Held to Maturity securities, less than 12 months, unrealized loss | $ 0 | $ 0
Available for sale securities, 12 months or longer, number of investment positions | 102 | 103
Held to Maturity securities, 12 months or longer, number of investment positions | 69 | 80
Available for sale securities, 12 months or longer, fair value | $ 177,288 | $ 192,963
Held to Maturity securities, 12 months or longer, fair value | 46,038 | 52,771
Available for sale securities, 12 months or longer, unrealized loss | (12,372) | (17,520)
Held to Maturity securities, 12 months or longer, unrealized loss | $ (2,887) | $ (4,218)
Available for sale securities, total, number of investment positions | 111 | 115
Held to Maturity securities, total, number of investment positions | 69 | 80
Available for sale securities, total, fair value | $ 195,161 | $ 210,993
Held to Maturity securities, total, fair value | 46,038 | 52,771
Available for sale securities, total, unrealized loss | (12,921) | (17,991)
Held to Maturity securities, total, unrealized loss | $ (2,887) | $ (4,218)
US States and Political Subdivisions Debt Securities [Member] |  |
Available for sale securities, less than 12 months, number of investment positions | 4 | 2
Held to Maturity securities, less than 12 months, number of investment positions | 11 | 24
Available for sale securities, less than 12 months, fair value | $ 4,649 | $ 2,764
Held to Maturity securities, less than 12 months, fair value | 8,534 | 15,822
Available for sale securities, less than 12 months, unrealized loss | (15) | (21)
Held to Maturity securities, less than 12 months, unrealized loss | $ (8) | $ (78)
Available for sale securities, 12 months or longer, number of investment positions | 39 | 40
Held to Maturity securities, 12 months or longer, number of investment positions | 24 | 26
Available for sale securities, 12 months or longer, fair value | $ 49,443 | $ 51,759
Held to Maturity securities, 12 months or longer, fair value | 22,673 | 25,814
Available for sale securities, 12 months or longer, unrealized loss | (1,145) | (1,680)
Held to Maturity securities, 12 months or longer, unrealized loss | $ (123) | $ (299)
Available for sale securities, total, number of investment positions | 43 | 42
Held to Maturity securities, total, number of investment positions | 35 | 50
Available for sale securities, total, fair value | $ 54,092 | $ 54,523
Held to Maturity securities, total, fair value | 31,207 | 41,636
Available for sale securities, total, unrealized loss | (1,160) | (1,701)
Held to Maturity securities, total, unrealized loss | $ (131) | $ (377)
Agency Commercial MBS [Member] |  |
Available for sale securities, less than 12 months, number of investment positions | 6 | 2
Available for sale securities, less than 12 months, fair value | $ 26,624 | $ 6,966
Available for sale securities, less than 12 months, unrealized loss | $ (65) | $ (132)
Available for sale securities, 12 months or longer, number of investment positions | 0 | 0
Available for sale securities, 12 months or longer, fair value | $ 0 | $ 0
Available for sale securities, 12 months or longer, unrealized loss | $ 0 | $ 0
Available for sale securities, total, number of investment positions | 6 | 2
Available for sale securities, total, fair value | $ 26,624 | $ 6,966
Available for sale securities, total, unrealized loss | $ (65) | $ (132)
Corporate Debt Securities [Member] |  |
Available for sale securities, less than 12 months, number of investment positions | 0 | 0
Held to Maturity securities, less than 12 months, number of investment positions | 10 | 23
Available for sale securities, less than 12 months, fair value | $ 0 | $ 0
Held to Maturity securities, less than 12 months, fair value | 51,063 | 251,790
Available for sale securities, less than 12 months, unrealized loss | 0 | 0
Held to Maturity securities, less than 12 months, unrealized loss | $ (234) | $ (4,230)
Available for sale securities, 12 months or longer, number of investment positions | 132 | 138
Held to Maturity securities, 12 months or longer, number of investment positions | 34 | 35
Available for sale securities, 12 months or longer, fair value | $ 1,792,021 | $ 1,824,327
Held to Maturity securities, 12 months or longer, fair value | 452,940 | 451,420
Available for sale securities, 12 months or longer, unrealized loss | (139,558) | (195,334)
Held to Maturity securities, 12 months or longer, unrealized loss | $ (14,662) | $ (28,007)
Available for sale securities, total, number of investment positions | 132 | 138
Held to Maturity securities, total, number of investment positions | 44 | 58
Available for sale securities, total, fair value | $ 1,792,021 | $ 1,824,327
Held to Maturity securities, total, fair value | 504,003 | 703,210
Available for sale securities, total, unrealized loss | (139,558) | (195,334)
Held to Maturity securities, total, unrealized loss | $ (14,896) | $ (32,237)
US Government Agencies Debt Securities [Member] |  |
Available for sale securities, less than 12 months, number of investment positions | 2 | 3
Available for sale securities, less than 12 months, fair value | $ 6,512 | $ 12,085
Available for sale securities, less than 12 months, unrealized loss | $ (2) | $ (53)
Available for sale securities, 12 months or longer, number of investment positions | 19 | 19
Available for sale securities, 12 months or longer, fair value | $ 285,159 | $ 275,467
Available for sale securities, 12 months or longer, unrealized loss | $ (10,539) | $ (19,032)
Available for sale securities, total, number of investment positions | 21 | 22
Available for sale securities, total, fair value | $ 291,671 | $ 287,552
Available for sale securities, total, unrealized loss | $ (10,541) | $ (19,085)
Collateralized Debt Obligations [Member] |  |
Available for sale securities, less than 12 months, number of investment positions | 7 | 3
Available for sale securities, less than 12 months, fair value | $ 93,767 | $ 26,825
Available for sale securities, less than 12 months, unrealized loss | $ (191) | $ (15)
Available for sale securities, 12 months or longer, number of investment positions | 22 | 32
Available for sale securities, 12 months or longer, fair value | $ 187,138 | $ 309,249
Available for sale securities, 12 months or longer, unrealized loss | $ (2,097) | $ (5,193)
Available for sale securities, total, number of investment positions | 29 | 35
Available for sale securities, total, fair value | $ 280,905 | $ 336,074
Available for sale securities, total, unrealized loss | $ (2,288) | $ (5,208)

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