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Note 2 - Securities - Credit Quality Indicators for Held to Maturity Securities (Details) - USD ($) $ in Thousands | Sep. 30, 2023 | Dec. 31, 2022
--- | --- | ---
Amortized cost, held to maturity securities |  | $ 150,079 | $ 153,158
Moody's, Aaa Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 64,551 | 64,043
Moody's, Aa1/Aa2/Aa3 Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 8,842 | 9,447
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] | 73,686 | 76,668
US Treasury Securities [Member] |  |  |
Amortized cost, held to maturity securities |  | 38,862 | 38,211
US Treasury Securities [Member] | Moody's, Aaa Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 38,862 | 38,211
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 |  | 96,563 | 99,374
US Agency and Mortgage-backed Securities [Member] | Moody's, Aaa Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 22,877 | 22,706
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] | 73,686 | 76,668
US States and Political Subdivisions Debt Securities [Member] |  |  |
Amortized cost, held to maturity securities |  | 11,654 | 12,573
US States and Political Subdivisions Debt Securities [Member] | Moody's, Aaa Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 2,812 | 3,126
US States and Political Subdivisions Debt Securities [Member] | Moody's, Aa1/Aa2/Aa3 Rating [Member] |  |  |
Amortized cost, held to maturity securities |  | 8,842 | 9,447
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 governmental guarantees associated with these agencies

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