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Note 4 - Securities - Investment Securities Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands | Mar. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Debt securities available for sale, less than twelve months, gross unrealized losses | $ (416) | $ (1,758)
Debt securities available for sale, less than twelve months, fair value | 48,968 | 276,720
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | (38,309) | (44,570)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 468,986 | 472,739
Debt Securities, Available for Sale, Gross Unrealized Losses | (38,725) | (46,328)
Debt Securities, Available for Sale, Fair Value | 517,954 | 749,459
State and municipal securities | (38,309) | (44,570)
State and municipal securities | (38,725) | (46,328)
U.S. Treasury securities | (194) | (536)
U.S. Treasury securities | 27,978 | 40,115
U.S. Treasury securities | (62,173) | (74,835)
U.S. Treasury securities | 593,504 | 593,233
U.S. Treasury securities | (62,367) | (75,371)
U.S. Treasury securities | 621,482 | 633,348
U.S. Treasury securities | (416) | (1,758)
U.S. Treasury securities | 48,968 | 276,720
US Treasury Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses | (2) | (445)
Debt securities available for sale, less than twelve months, fair value | 29,490 | 250,547
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | 0 | 0
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 0 | 0
Debt Securities, Available for Sale, Gross Unrealized Losses | (2) | (445)
Debt Securities, Available for Sale, Fair Value | 29,490 | 250,547
State and municipal securities | 0 | 0
State and municipal securities | (2) | (445)
U.S. Treasury securities | 0 | 0
U.S. Treasury securities | 0 | 0
U.S. Treasury securities | (15,765) | (19,632)
U.S. Treasury securities | 233,692 | 229,771
U.S. Treasury securities | (15,765) | (19,632)
U.S. Treasury securities | 233,692 | 229,771
U.S. Treasury securities | (2) | (445)
U.S. Treasury securities | 29,490 | 250,547
Collateralized Mortgage-Backed Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses | (1) | (6)
Debt securities available for sale, less than twelve months, fair value | 351 | 577
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | (20,067) | (24,204)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 174,934 | 179,178
Debt Securities, Available for Sale, Gross Unrealized Losses | (20,068) | (24,210)
Debt Securities, Available for Sale, Fair Value | 175,285 | 179,755
State and municipal securities | (20,067) | (24,204)
State and municipal securities | (20,068) | (24,210)
U.S. Treasury securities | (194) | (536)
U.S. Treasury securities | 27,978 | 40,115
U.S. Treasury securities | (45,911) | (54,614)
U.S. Treasury securities | 352,468 | 356,215
U.S. Treasury securities | (46,105) | (55,150)
U.S. Treasury securities | 380,446 | 396,330
U.S. Treasury securities | (1) | (6)
U.S. Treasury securities | 351 | 577
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 | (830) | (1,000)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 9,240 | 9,072
Debt Securities, Available for Sale, Gross Unrealized Losses | (830) | (1,000)
Debt Securities, Available for Sale, Fair Value | 9,240 | 9,072
State and municipal securities | (830) | (1,000)
State and municipal securities | (830) | (1,000)
U.S. Treasury securities | 0 | 0
U.S. Treasury securities | 0 | 0
U.S. Treasury securities | (497) | (589)
U.S. Treasury securities | 7,344 | 7,247
U.S. Treasury securities | (497) | (589)
U.S. Treasury securities | 7,344 | 7,247
U.S. Treasury securities | 0 | 0
U.S. Treasury securities | 0 | 0
Corporate Debt Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses | (413) | (1,307)
Debt securities available for sale, less than twelve months, fair value | 19,127 | 25,596
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | (17,412) | (19,366)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 284,812 | 284,489
Debt Securities, Available for Sale, Gross Unrealized Losses | (17,825) | (20,673)
Debt Securities, Available for Sale, Fair Value | 303,939 | 310,085
State and municipal securities | (17,412) | (19,366)
State and municipal securities | (17,825) | (20,673)
U.S. Treasury securities | (413) | (1,307)
U.S. Treasury securities | $ 19,127 | $ 25,596

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