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Note 4 - Securities - Investment Securities Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands | Sep. 30, 2024 | Dec. 31, 2023
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Debt securities available for sale, less than twelve months, gross unrealized losses | $ (1,505) | $ (801)
Debt securities available for sale, less than twelve months, fair value | 20,421 | 15,845
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | (45,490) | (68,365)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 500,544 | 535,836
Debt Securities, Available for Sale, Gross Unrealized Losses | (46,994) | (69,166)
Debt Securities, Available for Sale, Fair Value | 520,965 | 551,681
Debt Securities held to maturity less than twelve months, gross unrealized losses | 0 | (1)
Debt securities, held to maturity, Less Than Twelve Months, Fair Value | 2,061 | 430
Debt Securities Held To Maturity, Twelve Months or More, Gross Unrealized Losses | (56,122) | (75,474)
Debt Securities, Held To Maturity, Twelve Months or More, Fair Value | 624,309 | 902,933
Debt Securities, Held To Maturity , Gross Unrealized Losses | (56,122) | (75,475)
Debt Securities,Held To Maturity, Fair Value | 626,369 | 903,363
State and municipal securities | 1,505 | 801
Collateralized Mortgage-Backed Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses | 0 | (6)
Debt securities available for sale, less than twelve months, fair value | 1 | 704
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | (19,120) | (25,973)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 193,011 | 214,393
Debt Securities, Available for Sale, Gross Unrealized Losses | (19,120) | (25,979)
Debt Securities, Available for Sale, Fair Value | 193,012 | 215,097
Debt Securities held to maturity less than twelve months, gross unrealized losses | 0 | (1)
Debt securities, held to maturity, Less Than Twelve Months, Fair Value | 2,061 | 430
Debt Securities Held To Maturity, Twelve Months or More, Gross Unrealized Losses | (39,398) | (50,024)
Debt Securities, Held To Maturity, Twelve Months or More, Fair Value | 383,853 | 411,585
Debt Securities, Held To Maturity , Gross Unrealized Losses | (39,398) | (50,025)
Debt Securities,Held To Maturity, Fair Value | 385,914 | 412,015
State and municipal securities | (0) | 6
US States and Political Subdivisions Debt Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses | 0 | 0
Debt securities available for sale, less than twelve months, fair value | 0 | 0
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | (826) | (1,178)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 9,273 | 9,777
Debt Securities, Available for Sale, Gross Unrealized Losses | (826) | (1,178)
Debt Securities, Available for Sale, Fair Value | 9,273 | 9,777
Debt Securities held to maturity less than twelve months, gross unrealized losses | 0 | 0
Debt securities, held to maturity, Less Than Twelve Months, Fair Value | 0 | 0
Debt Securities Held To Maturity, Twelve Months or More, Gross Unrealized Losses | (498) | (732)
Debt Securities, Held To Maturity, Twelve Months or More, Fair Value | 7,332 | 7,081
Debt Securities, Held To Maturity , Gross Unrealized Losses | (498) | (732)
Debt Securities,Held To Maturity, Fair Value | 7,332 | 7,081
State and municipal securities | (0) | 0
Corporate Debt Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses | (1,505) | (794)
Debt securities available for sale, less than twelve months, fair value | 20,420 | 15,141
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | (25,544) | (41,214)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 298,260 | 311,666
Debt Securities, Available for Sale, Gross Unrealized Losses | (27,048) | (42,009)
Debt Securities, Available for Sale, Fair Value | 318,680 | 326,807
State and municipal securities | 1,505 | 794
US Treasury Securities [Member] |  |
Debt Securities held to maturity less than twelve months, gross unrealized losses | 0 | 0
Debt securities, held to maturity, Less Than Twelve Months, Fair Value | 0 | 0
Debt Securities Held To Maturity, Twelve Months or More, Gross Unrealized Losses | (16,226) | (24,718)
Debt Securities, Held To Maturity, Twelve Months or More, Fair Value | 233,124 | 484,267
Debt Securities, Held To Maturity , Gross Unrealized Losses | (16,226) | (24,718)
Debt Securities,Held To Maturity, Fair Value | $ 233,123 | $ 484,267

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