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Note 6 - Fair Value Measurements - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands | Jun. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Equity securities at fair value (Note 2) | $ 2,905 | $ 2,851
Securities available for sale (Note 2) | 372,525 | 339,579
Equity Securities [Member] |  |
Equity securities at fair value (Note 2) | 2,905 | 2,851
US Treasury and Government [Member] |  |
Equity securities at fair value (Note 2) | 2,065 | 17,215
Securities available for sale (Note 2) | 2,065 | 17,215
US Treasury Securities [Member] |  |
Equity securities at fair value (Note 2) | 2,070 | 2,008
Securities available for sale (Note 2) | 2,070 | 2,008
US States and Political Subdivisions Debt Securities [Member] |  |
Equity securities at fair value (Note 2) | 263,930 | 173,924
Securities available for sale (Note 2) | 263,930 | 173,924
Collateralized Mortgage Backed Securities [Member] |  |
Equity securities at fair value (Note 2) | 100,575 | 142,760
Securities available for sale (Note 2) | 100,575 | 142,760
Corporate Debt Securities [Member] |  |
Equity securities at fair value (Note 2) | 2,885 | 2,672
Securities available for sale (Note 2) | 2,885 | 2,672
Trust Preferred Securities [Member] |  |
Equity securities at fair value (Note 2) | 1,000 | 1,000
Securities available for sale (Note 2) | 1,000 | 1,000
Fair Value, Recurring [Member] |  |
Securities available for sale (Note 2) | 372,525 | 339,579
Fair Value, Recurring [Member] | Equity Securities [Member] |  |
Equity securities at fair value (Note 2) | 2,905 | 2,851
Fair Value, Recurring [Member] | US Treasury and Government [Member] |  |
Securities available for sale (Note 2) | 2,065 | 17,215
Fair Value, Recurring [Member] | US Treasury Securities [Member] |  |
Securities available for sale (Note 2) | 2,070 | 2,008
Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] |  |
Securities available for sale (Note 2) | 263,930 | 173,924
Fair Value, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] |  |
Securities available for sale (Note 2) | 100,575 | 142,760
Fair Value, Recurring [Member] | Corporate Debt Securities [Member] |  |
Securities available for sale (Note 2) | 2,885 | 2,672
Fair Value, Recurring [Member] | Trust Preferred Securities [Member] |  |
Securities available for sale (Note 2) | 1,000 | 1,000
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] |  |
Securities available for sale (Note 2) | 0 | 0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Equity Securities [Member] |  |
Equity securities at fair value (Note 2) | 1,425 | 1,379
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member] |  |
Securities available for sale (Note 2) | 0 | 0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | US Treasury Securities [Member] |  |
Securities available for sale (Note 2) | 0 | 0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] |  |
Securities available for sale (Note 2) | 0 | 0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] |  |
Securities available for sale (Note 2) | 0 | 0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member] |  |
Securities available for sale (Note 2) | 0 | 0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Trust Preferred Securities [Member] |  |
Securities available for sale (Note 2) | 0 | 0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] |  |
Securities available for sale (Note 2) | 360,380 | 327,212
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Equity Securities [Member] |  |
Equity securities at fair value (Note 2) | 0 | 0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member] |  |
Securities available for sale (Note 2) | 2,065 | 17,215
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | US Treasury Securities [Member] |  |
Securities available for sale (Note 2) | 2,070 | 2,008
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] |  |
Securities available for sale (Note 2) | 252,785 | 162,557
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] |  |
Securities available for sale (Note 2) | 100,575 | 142,760
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member] |  |
Securities available for sale (Note 2) | 2,885 | 2,672
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Trust Preferred Securities [Member] |  |
Securities available for sale (Note 2) | 0 | 0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] |  |
Securities available for sale (Note 2) | 12,145 | 12,367
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Equity Securities [Member] |  |
Equity securities at fair value (Note 2) | 1,480 | 1,472
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | US Treasury and Government [Member] |  |
Securities available for sale (Note 2) | 0 | 0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | US Treasury Securities [Member] |  |
Securities available for sale (Note 2) | 0 | 0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] |  |
Securities available for sale (Note 2) | 11,145 | 11,367
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] |  |
Securities available for sale (Note 2) | 0 | 0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Corporate Debt Securities [Member] |  |
Securities available for sale (Note 2) | 0 | 0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Trust Preferred Securities [Member] |  |
Securities available for sale (Note 2) | $ 1,000 | $ 1,000

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