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Note 5 - Fair Value Measurements - Assets Measured on a Recurring Basis (Details) - USD ($) | Sep. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Total debt securities | $ 163,057,000 | $ 114,360,000
Equity securities in financial institutions | 833,000 | 609,000
Investment securities available for sale, at fair value | 163,057,000 | 114,360,000
Subordinated Debt Securities [Member] |  |
Total debt securities | 32,620,000 | 21,297,000
Investment securities available for sale, at fair value | 32,620,000 | 21,297,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Total debt securities | 11,389,000 | 14,761,000
Investment securities available for sale, at fair value | 11,389,000 | 14,761,000
Fair Value, Recurring [Member] |  |
Total debt securities | 163,057,000 | 114,360,000
Equity securities in financial institutions | 833,000 | 609,000
Total | 163,890,000 | 114,969,000
Investment securities available for sale, at fair value | 163,057,000 | 114,360,000
Fair Value, Recurring [Member] | Subordinated Debt Securities [Member] |  |
Total debt securities | 32,620,000 | 21,297,000
Investment securities available for sale, at fair value | 32,620,000 | 21,297,000
Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member] |  |
Total debt securities | 119,048,000 | 78,302,000
Investment securities available for sale, at fair value | 119,048,000 | 78,302,000
Fair Value, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Total debt securities | 11,389,000 | 14,761,000
Investment securities available for sale, at fair value | 11,389,000 | 14,761,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Total debt securities | 0 | 0
Equity securities in financial institutions | 833,000 | 609,000
Total | 833,000 | 609,000
Investment securities available for sale, at fair value | 0 | 0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Subordinated Debt Securities [Member] |  |
Total debt securities | 0 | 0
Investment securities available for sale, at fair value | 0 | 0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member] |  |
Total debt securities | 0 | 0
Investment securities available for sale, at fair value | 0 | 0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Total debt securities | 0 | 0
Investment securities available for sale, at fair value | 0 | 0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Total debt securities | 151,370,000 | 107,110,000
Equity securities in financial institutions | 0 | 0
Total | 151,370,000 | 107,110,000
Investment securities available for sale, at fair value | 151,370,000 | 107,110,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Subordinated Debt Securities [Member] |  |
Total debt securities | 20,933,000 | 14,047,000
Investment securities available for sale, at fair value | 20,933,000 | 14,047,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member] |  |
Total debt securities | 119,048,000 | 78,302,000
Investment securities available for sale, at fair value | 119,048,000 | 78,302,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Total debt securities | 11,389,000 | 14,761,000
Investment securities available for sale, at fair value | 11,389,000 | 14,761,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Total debt securities | 11,687,000 | 7,250,000
Equity securities in financial institutions | 0 | 0
Total | 11,687,000 | 7,250,000
Investment securities available for sale, at fair value | 11,687,000 | 7,250,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Subordinated Debt Securities [Member] |  |
Total debt securities | 11,687,000 | 7,250,000
Investment securities available for sale, at fair value | 11,687,000 | 7,250,000
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member] |  |
Total debt securities | 0 | 0
Investment securities available for sale, at fair value | 0 | 0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |
Total debt securities | 0 | 0
Investment securities available for sale, at fair value | $ 0 | $ 0

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- Definition Amount of 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://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=124260329&loc=d3e26610-111562 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563 + Details
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