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Note 5 - Fair Value Measurements - Assets Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Total debt securities	$ 102,959	$ 105,733
Equity securities in financial institutions	550	710
Investment securities available for sale, at fair value	102,959	105,733
Subordinated Debt Securities [Member]
Total debt securities	4,221	4,126
Investment securities available for sale, at fair value	4,221	4,126
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Total debt securities	17,482	18,630
Investment securities available for sale, at fair value	17,482	18,630
Fair Value, Recurring [Member]
Total debt securities	102,959	105,733
Equity securities in financial institutions	550	710
Total	103,509	106,443
Investment securities available for sale, at fair value	102,959	105,733
Fair Value, Recurring [Member] | Subordinated Debt Securities [Member]
Total debt securities	4,221	4,126
Investment securities available for sale, at fair value	4,221	4,126
Fair Value, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member]
Total debt securities	81,256	82,977
Investment securities available for sale, at fair value	81,256	82,977
Fair Value, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Total debt securities	17,482	18,630
Investment securities available for sale, at fair value	17,482	18,630
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Total debt securities
Equity securities in financial institutions	550	710
Total	550	710
Investment securities available for sale, at fair value
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Subordinated Debt Securities [Member]
Total debt securities
Investment securities available for sale, at fair value
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member]
Total debt securities
Investment securities available for sale, at fair value
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Total debt securities
Investment securities available for sale, at fair value
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Total debt securities	102,959	105,733
Equity securities in financial institutions
Total	102,959	105,733
Investment securities available for sale, at fair value	102,959	105,733
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Subordinated Debt Securities [Member]
Total debt securities	4,221	4,126
Investment securities available for sale, at fair value	4,221	4,126
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Total debt securities	81,256	82,977
Investment securities available for sale, at fair value	81,256	82,977
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Total debt securities	17,482	18,630
Investment securities available for sale, at fair value	17,482	18,630
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Total debt securities
Equity securities in financial institutions
Total
Investment securities available for sale, at fair value
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Subordinated Debt Securities [Member]
Total debt securities
Investment securities available for sale, at fair value
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member]
Total debt securities
Investment securities available for sale, at fair value
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Total debt securities
Investment securities available for sale, at fair value

X

- 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

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- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740

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- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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