Note 7 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Expense (Benefit), Total		$ 963,000	$ 269,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	21.00%
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount		$ 0	$ 19,000
Unrecognized Tax Benefits, Ending Balance		278,000	$ 295,000	$ 275,000
Unrecognized Tax Benefits, Income Tax Penalties Accrued		43,000
Unrecognized Tax Benefits, Interest on Income Taxes Accrued		0
Forecast [Member] | Maximum [Member]
Unrecognized Tax Benefits, Decrease Resulting from Foreign Taxes	$ 100,000
Domestic Tax Authority [Member]
Operating Loss Carryforwards		0
Domestic Tax Authority [Member] | Capital Loss Carryforward [Member]
Tax Credit Carryforward, Amount		2,679,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards		2,604,000
State and Local Jurisdiction [Member] | Capital Loss Carryforward [Member]
Tax Credit Carryforward, Amount		$ 129,000