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Note 7 - Investment and Equity Securities - Amortized Cost and Fair Values of Securities Available for Sale (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Amortized cost | $ 158,487 | $ 108,937
Gross unrealized gains | 4,939 | 5,435
Gross unrealized losses | (369) | (12)
Investment securities available for sale, at fair value | 163,057 | 114,360
Subordinated Debt Securities [Member] |  |
Amortized cost | 32,300 | 21,050
Gross unrealized gains | 378 | 254
Gross unrealized losses | (58) | (7)
Investment securities available for sale, at fair value | 32,620 | 21,297
Taxable Municipal Bonds [Member] |  |
Amortized cost | 500 | 500
Gross unrealized gains | 2 | 2
Gross unrealized losses | 0 | 0
Investment securities available for sale, at fair value | 502 | 502
Nontaxable Municipal Bonds [Member] |  |
Amortized cost | 114,603 | 73,157
Gross unrealized gains | 4,194 | 4,643
Gross unrealized losses | (251) | 0
Investment securities available for sale, at fair value | 118,546 | 77,800
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Amortized cost | 11,084 | 14,230
Gross unrealized gains | 365 | 536
Gross unrealized losses | (60) | (5)
Investment securities available for sale, at fair value | $ 11,389 | $ 14,761

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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=123581744&loc=d3e27161-111563 + Details
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