Note 4 - Investment Securities (Details Textual)	12 Months Ended
Dec. 31, 2021 USD ($) security	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Investment Securities [Line Items]
Proceeds from sale of investment securities	$ 282,000	$ 6,930,000	$ 47,851,000
Other than temporary impairment charges recognized for debt securities	0	0	0
Other than temporary impairment, credit losses recognized in earnings	0	0	0
Available-for-sale securities pledged as collateral	$ 264,154,000	$ 220,934,000
Debt Securities, Available-for-Sale, Restriction Type [Extensible Enumeration]	us-gaap:AssetPledgedAsCollateralMember	us-gaap:AssetPledgedAsCollateralMember
Investment equity securities	$ 12,410,000	$ 12,849,000
Unrealized (gains) losses, net of tax	9,375,000	(5,411,000)	(7,368,000)
Proceeds from sale of investment equity securities	7,768,000	4,767,000	11,838,000
Debt Securities [Member]
Investment Securities [Line Items]
Income tax expense (benefit) related to net realized gains (losses) on sales of securities	$ 4,000	5,000	(5,000)
PreTSL IV [Member]
Investment Securities [Line Items]
Number of trust preferred securities \| security	1
Equity Securities [Member]
Investment Securities [Line Items]
Income tax expense (benefit) related to net realized gains (losses) on sales of securities	$ 784,000	$ 155,000	$ 737,000

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

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 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 954
-SubTopic 210
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=120413173&loc=SL6242262-115580

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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

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
-Paragraph 1A
-Subparagraph (b)(2)
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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), classified as current.

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Amount, after tax and before adjustment, of unrealized holding gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Excludes unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.

+ References

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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

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Amount of other-than-temporary impairment (OTTI) on investment in debt security, recognized in earnings.

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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).

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