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Note 2 - Securities - Credit Quality Indicators for Held to Maturity Securities (Details) - USD ($) $ in Thousands | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Amortized cost, held to maturity securities |  | $ 125,941 | $ 148,351
Moody's, Aaa Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 45,073 | 64,828
Moody's, Aa1/Aa2/Aa3 Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 8,843 | 8,842
Moody's, Baa1/ Baa2/ Baa3 Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 3,000 | 3,000
Not Rated - Agency [Member] |  |  |
Amortized cost, held to maturity securities | [1] | 69,025 | 71,681
US Treasury Securities [Member] |  |  |
Amortized cost, held to maturity securities |  | 19,277 | 39,085
US Treasury Securities [Member] | Moody's, Aaa Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 19,277 | 39,085
US Treasury Securities [Member] | Moody's, Aa1/Aa2/Aa3 Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 0 | 0
US Treasury Securities [Member] | Moody's, Baa1/ Baa2/ Baa3 Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 0 | 0
US Treasury Securities [Member] | Not Rated - Agency [Member] |  |  |
Amortized cost, held to maturity securities | [1] | 0 | 0
US Agency and Mortgage-backed Securities [Member] |  |  |
Amortized cost, held to maturity securities |  | 92,019 | 94,617
US Agency and Mortgage-backed Securities [Member] | Moody's, Aaa Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 22,994 | 22,936
US Agency and Mortgage-backed Securities [Member] | Moody's, Aa1/Aa2/Aa3 Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 0 | 0
US Agency and Mortgage-backed Securities [Member] | Moody's, Baa1/ Baa2/ Baa3 Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 0 | 0
US Agency and Mortgage-backed Securities [Member] | Not Rated - Agency [Member] |  |  |
Amortized cost, held to maturity securities | [1] | 69,025 | 71,681
US States and Political Subdivisions Debt Securities [Member] |  |  |
Amortized cost, held to maturity securities |  | 11,645 | 11,649
US States and Political Subdivisions Debt Securities [Member] | Moody's, Aaa Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 2,802 | 2,807
US States and Political Subdivisions Debt Securities [Member] | Moody's, Aa1/Aa2/Aa3 Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 8,843 | 8,842
US States and Political Subdivisions Debt Securities [Member] | Moody's, Baa1/ Baa2/ Baa3 Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 0 | 0
US States and Political Subdivisions Debt Securities [Member] | Not Rated - Agency [Member] |  |  |
Amortized cost, held to maturity securities | [1] | 0 | 0
Corporate Debt Securities [Member] |  |  |
Amortized cost, held to maturity securities |  | 3,000 | 3,000
Corporate Debt Securities [Member] | Moody's, Aaa Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 0 | 0
Corporate Debt Securities [Member] | Moody's, Aa1/Aa2/Aa3 Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 0 | 0
Corporate Debt Securities [Member] | Moody's, Baa1/ Baa2/ Baa3 Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 3,000 | 3,000
Corporate Debt Securities [Member] | Not Rated - Agency [Member] |  |  |
Amortized cost, held to maturity securities | [1] | $ 0 | $ 0
[1] | Generally considered not to have credit risk given the implied governmental guarantees associated with these agencies.

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