Note 3 - Securities (Details Textual)	12 Months Ended
Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Equity Securities, FV-NI, Current	$ 0	$ 0
Equity Securities, FV-NI, Unrealized Gain	(0)	(0)	$ 333,000
Debt Securities, Available-for-sale, Restricted	150,400,000	189,791,000
Federal Home Loan Bank Letters of Credit Used as Additional Collateral Amount	275,000,000	245,000,000
Federal Reserve Bank Stock	6,500,000	6,458,000
Federal Home Loan Bank Stock	1,556,000	2,257,000
Other than Temporary Impairment Losses, Investments, Total	$ 0	$ 0
US Treasury Securities [Member]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions	17
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions	0
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Total	$ 0
US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions	26
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions	12
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Total	$ 0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions	18
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions	4
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Total	$ 0
Collateralized Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions	33
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions	4
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Total	$ 0
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions	39
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions	2
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Total	$ 0
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions	0
Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale, Total	$ 0

This line item represents federal home loan bank letters of credit which were used as additional collateral amount.

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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 continuous unrealized loss position for 12 months or longer, without an allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

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-Publisher FASB
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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).

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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.

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

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- Definition

Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Federal Reserve Bank stock represents an equity interest in the Federal Reserve Bank. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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The amount by which the fair value of an investment 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.

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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).

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