Note 13 - Stock-based Compensation (Details Textual) - USD ($)	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Feb. 20, 2018
Proceeds from Stock Options Exercised	$ 12,000	$ 89,000	$ 43,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 16,000	$ 96,000	$ 42,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)	0	0	0
Regular Quarterly Retainer of Vested Restricted Stock	$ 10,000	$ 10,000	$ 10,000
Monthly Meeting Fees Director Could Receive in Cash	800	800	800
Monthly Meeting Fees Director Could Receive in Vested Restricted Stock	1,000	1,000	1,000
Share-Based Payment Arrangement, Option [Member]
Share-Based Payment Arrangement, Expense	0	0
Restricted Stock [Member]
Share-Based Payment Arrangement, Expense	889,000	749,000	672,000
Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount	1,100,000	782,000	797,000
Restricted Stock [Member] \| Director [Member]
Share-Based Payment Arrangement, Expense	$ 603,000	$ 683,000	$ 779,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period (in shares)	16,474	20,474	27,986
Restricted Stock [Member] \| Minimum [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Month)	12 months
Restricted Stock [Member] \| Maximum [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Month)	36 months
Restricted Stock [Member] \| Cliff Vested [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Month)	36 months
The 2018 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)				675,000

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Gross number of share options (or share units) granted during the period.

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