Note 6 - Investment Securities (Details Textual)	3 Months Ended
Mar. 31, 2020 USD ($) security	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Investment Securities [Line Items]
Proceeds from sale of investment securities	$ 5,975,000	$ 11,192,000
Available-for-sale securities pledged as collateral	$ 190,462,000		$ 205,016,000
Debt Securities, Available-for-sale, Restriction Type [Extensible List]	us-gaap:CollateralPledgedMember		us-gaap:CollateralPledgedMember
Investment equity securities	$ 9,417,000		$ 9,164,000
Proceeds from the sale of equity securities	0	358,000
Debt Securities [Member]
Investment Securities [Line Items]
Income tax expense (benefit) related to net realized gains (losses) on sales of securities	0	8,000
Other than temporary impairment, credit losses recognized in earnings	$ 0	0
PreTSL [Member]
Investment Securities [Line Items]
Number of trust preferred securities \| security	1
Available-for-sale, amortized cost	$ 85,000
Fair value	71,000
Equity Securities [Member]
Investment Securities [Line Items]
Income tax expense (benefit) related to net recognized gains (losses) on sales of securities	$ (849,000)	$ 295,000

Income tax expense (benefit) during the period related to net realized gains (losses) on sales of securities.

No definition available.

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- Definition

Income tax expense (benefit) during the period related to net recognized gains (losses) on sales of securities.

+ References

No definition available.

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- Definition

Investment securities.

+ References

No definition available.

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- Definition

The number of trust preferred securities held by the entity.

+ References

No definition available.

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- Definition

Proceeds from sale of investment in equity securities.

+ References

No definition available.

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- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

No definition available.

+ Details

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- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ 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

Indicates type of restriction 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://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

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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
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-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740

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- Definition

This item represents an increase to the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held for which a previous OTTI was recognized and the investor does not intend to sell the debt security and it is not more likely than not that the investor will be required to sell the debt security before recovery of its amortized cost basis.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 8B
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=SL6284393-111563

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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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
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