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Note 4 - Investment and Equity Securities - Gross Unrealized Losses and Fair Value (Details) - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Less than Twelve Months, Fair Value | $ 6,991 | $ 5,733
Less than Twelve Months, Gross Unrealized Losses | (12) | (27)
Twelve Months or Greater, Fair Value | 0 | 8,223
Twelve Months or Greater, Gross Unrealized Losses | 0 | (107)
Total, Fair Value | 6,991 | 13,956
Total, Gross Unrealized Losses | (12) | (134)
Subordinated Debt Securities [Member] |  |
Less than Twelve Months, Fair Value | 4,243 |
Less than Twelve Months, Gross Unrealized Losses | (7) |
Twelve Months or Greater, Fair Value | 0 |
Twelve Months or Greater, Gross Unrealized Losses | 0 |
Total, Fair Value | 4,243 |
Total, Gross Unrealized Losses | (7) |
Nontaxable Municipal Bonds [Member] |  |
Less than Twelve Months, Fair Value |  | 4,324
Less than Twelve Months, Gross Unrealized Losses |  | (25)
Twelve Months or Greater, Fair Value |  | 0
Twelve Months or Greater, Gross Unrealized Losses |  | 0
Total, Fair Value |  | 4,324
Total, Gross Unrealized Losses |  | (25)
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Less than Twelve Months, Fair Value | 2,748 | 1,409
Less than Twelve Months, Gross Unrealized Losses | (5) | (2)
Twelve Months or Greater, Fair Value | 0 | 8,223
Twelve Months or Greater, Gross Unrealized Losses | 0 | (107)
Total, Fair Value | 2,748 | 9,632
Total, Gross Unrealized Losses | $ (5) | $ (109)

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