Note 3 - Available-for-sale Securities (Details Textual) $ in Thousands	3 Months Ended
Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions	26		22
Number of Available-for-sale Securities	41		37
Unrealized Holding Losses Depreciation Percentage from Amortized Cost	3.60%		4.00%
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Total	$ 0
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Total	0
Payments to Acquire Debt Securities, Available-for-sale		$ 0
Proceeds from Sale of Debt Securities, Available-for-sale	0	$ 0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Payments to Acquire Debt Securities, Available-for-sale	10,900
SBA Loan Pools [Member]
Payments to Acquire Debt Securities, Available-for-sale	3,000
Available-For-Sale Securities Pledged to Secure Municipal Deposits [Member]
Debt Securities, Available-for-sale, Restricted	$ 5,600		$ 6,100

The number of available-for-sale securities held.

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- Definition

Unrealized holding losses depreciation percentage from amortized cost.

+ References

No definition available.

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- Definition

Amount of restricted 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 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

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- Definition

Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
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Amount of other-than-temporary impairment (OTTI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), recognized in earnings and other comprehensive loss (OCI).

+ References

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-Name Accounting Standards Codification
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-SubTopic 10
-Section 45
-Paragraph 8A
-URI http://asc.fasb.org/extlink&oid=121553693&loc=SL6284422-111562

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- Definition

The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

No definition available.

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- Definition

Amount of cash outflow to acquire 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
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- Definition

Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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-Publisher FASB
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