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Note 7 - Stock-based Compensation (Details Textual) - USD ($)		3 Months Ended			6 Months Ended		12 Months Ended
	Jan. 04, 2017	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2019
Incentive Compensation Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)		2,580,000			2,580,000
Share-based Payment Arrangement, Expense		$ 96,000	$ 53,000		$ 203,000	$ 109,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total		$ 6,000			$ 6,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)					3 years
Performance Share Award Agreement [Member] | Performance Shares [Member]
Share-based Payment Arrangement, Expense							$ 108,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total				$ 434,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	161,766
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares)				129,000

X

- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
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Aggregate number of common shares reserved for future issuance.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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