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Note 12 - Fair Value Measurements - Balances of Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands | Mar. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Fair value, available for sale securities | $ 128,660 | $ 120,983
Fair Value, Inputs, Level 1 [Member] |  |
Fair value, available for sale securities |  |
Fair Value, Inputs, Level 2 [Member] |  |
Fair value, available for sale securities |  | 120,983
Fair Value, Inputs, Level 3 [Member] |  |
Fair value, available for sale securities |  |
Fair Value, Recurring [Member] |  |
Fair value, available for sale securities | 128,660 |
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair value, available for sale securities |  |
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair value, available for sale securities | 128,660 |
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair value, available for sale securities |  |
US Agency and Mortgage-backed Securities [Member] |  |
Fair value, available for sale securities | 102,597 | 94,905
US Agency and Mortgage-backed Securities [Member] | Fair Value, Recurring [Member] |  |
Fair value, available for sale securities | 102,597 | 94,905
US Agency and Mortgage-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair value, available for sale securities |  |
US Agency and Mortgage-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair value, available for sale securities | 102,597 | 94,905
US Agency and Mortgage-backed Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair value, available for sale securities |  |
Municipal Bonds [Member] |  |
Fair value, available for sale securities | 26,063 | 26,078
Municipal Bonds [Member] | Fair Value, Recurring [Member] |  |
Fair value, available for sale securities | 26,063 | 26,078
Municipal Bonds [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair value, available for sale securities |  |
Municipal Bonds [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair value, available for sale securities | 26,063 | 26,078
Municipal Bonds [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair value, available for sale securities |  |

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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=121558606&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=121553693&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=121645371&loc=d3e27161-111563 + Details
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