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Note 11 - Fair Values - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) | Mar. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Debt Securities, Available-for-sale, Total | $ 434,257,000 | $ 387,347,000
Fair Value, Inputs, Level 1 [Member] |  |
Debt Securities, Available-for-sale, Total | 0 | 0
US Government Agencies Debt Securities [Member] |  |
Debt Securities, Available-for-sale, Total | 266,828,000 | 242,141,000
Collateralized Mortgage Backed Securities [Member] |  |
Debt Securities, Available-for-sale, Total | 35,808,000 | 24,890,000
Municipal General Obligation Bonds [Member] |  |
Debt Securities, Available-for-sale, Total | 115,537,000 | 107,824,000
Municipal Revenue Bonds [Member] |  |
Debt Securities, Available-for-sale, Total | 15,584,000 | 11,992,000
Other Debt and Equity Securities [Member] |  |
Debt Securities, Available-for-sale, Total | 500,000 | 500,000
Fair Value, Recurring [Member] |  |
Debt Securities, Available-for-sale, Total | 434,257,000 | 387,347,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt Securities, Available-for-sale, Total | 0 | 0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt Securities, Available-for-sale, Total | 433,491,000 | 386,581,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt Securities, Available-for-sale, Total | 766,000 | 766,000
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member] |  |
Debt Securities, Available-for-sale, Total | 266,828,000 | 242,141,000
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt Securities, Available-for-sale, Total | 0 | 0
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt Securities, Available-for-sale, Total | 266,828,000 | 242,141,000
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt Securities, Available-for-sale, Total | 0 | 0
Fair Value, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] |  |
Debt Securities, Available-for-sale, Total | 35,808,000 | 24,890,000
Fair Value, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt Securities, Available-for-sale, Total | 0 | 0
Fair Value, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt Securities, Available-for-sale, Total | 35,808,000 | 24,890,000
Fair Value, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt Securities, Available-for-sale, Total | 0 | 0
Fair Value, Recurring [Member] | Municipal General Obligation Bonds [Member] |  |
Debt Securities, Available-for-sale, Total | 115,537,000 | 107,824,000
Fair Value, Recurring [Member] | Municipal General Obligation Bonds [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt Securities, Available-for-sale, Total | 0 | 0
Fair Value, Recurring [Member] | Municipal General Obligation Bonds [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt Securities, Available-for-sale, Total | 114,771,000 | 107,058,000
Fair Value, Recurring [Member] | Municipal General Obligation Bonds [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt Securities, Available-for-sale, Total | 766,000 | 766,000
Fair Value, Recurring [Member] | Municipal Revenue Bonds [Member] |  |
Debt Securities, Available-for-sale, Total | 15,584,000 | 11,992,000
Fair Value, Recurring [Member] | Municipal Revenue Bonds [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt Securities, Available-for-sale, Total | 0 | 0
Fair Value, Recurring [Member] | Municipal Revenue Bonds [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt Securities, Available-for-sale, Total | 15,584,000 | 11,992,000
Fair Value, Recurring [Member] | Municipal Revenue Bonds [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt Securities, Available-for-sale, Total | 0 | 0
Fair Value, Recurring [Member] | Other Debt and Equity Securities [Member] |  |
Debt Securities, Available-for-sale, Total | 500,000 | 500,000
Fair Value, Recurring [Member] | Other Debt and Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Debt Securities, Available-for-sale, Total | 0 | 0
Fair Value, Recurring [Member] | Other Debt and Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Debt Securities, Available-for-sale, Total | 500,000 | 500,000
Fair Value, Recurring [Member] | Other Debt and Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Debt Securities, Available-for-sale, Total | $ 0 | $ 0

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