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Note 4 - Investment and Equity Securities - Amortized Cost and Fair Values of Securities Available for Sale (Details) - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Amortized cost | $ 103,401 | $ 98,516
Gross unrealized gains | 2,466 | 855
Gross unrealized losses | (134) | (1,049)
Investment securities available for sale, at fair value | 105,733 | 98,322
Subordinated Debt Securities [Member] |  |
Amortized cost | 4,000 |
Gross unrealized gains | 126 |
Gross unrealized losses |  |
Investment securities available for sale, at fair value | 4,126 |
US Government Agencies Debt Securities [Member] |  |
Amortized cost |  | 7,442
Gross unrealized gains |  | 90
Gross unrealized losses |  | (61)
Investment securities available for sale, at fair value |  | 7,471
Taxable Municipal Bonds [Member] |  |
Amortized cost | 500 | 502
Gross unrealized gains | 1 | 10
Gross unrealized losses |  |
Investment securities available for sale, at fair value | 501 | 512
Nontaxable Municipal Bonds [Member] |  |
Amortized cost | 80,436 | 72,387
Gross unrealized gains | 2,065 | 667
Gross unrealized losses | (25) | (473)
Investment securities available for sale, at fair value | 82,476 | 72,581
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Amortized cost | 18,465 | 18,185
Gross unrealized gains | 274 | 88
Gross unrealized losses | (109) | (515)
Investment securities available for sale, at fair value | $ 18,630 | $ 17,758

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- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 + Details
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- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 + Details
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