Note 1 - Organization and Summary of Significant Accounting Policies (Details Textual) - USD ($)		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022
Investments		$ 4,062,000	$ 5,180,000
Share-Based Payment Arrangement, Expense		$ 150,000	$ 210,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)		0	0
The 2020 Non-employee Director Stock Option Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period		6,021	8,808
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)	[1],[2],[3]	6,021	8,808
General and Administrative Expense [Member]
Depreciation		$ 6,256,000	$ 5,697,000
Computer Software, Intangible Asset [Member]
Amortization of Intangible Assets		$ 0	0
Computer Software, Intangible Asset [Member] | Minimum [Member]
Finite-Lived Intangible Asset, Useful Life		3 years
Computer Software, Intangible Asset [Member] | Maximum [Member]
Finite-Lived Intangible Asset, Useful Life		7 years
Customer Relationships [Member]
Amortization of Intangible Assets		$ 133,000	133,000
Customer Relationships [Member] | Other Long-term Assets [Member]
Finite-Lived Intangible Assets, Net		$ 34,000	$ 167,000

[1] Indicates plans with stock grants.

[2] Indicates plans with stock options.

[3] The 2020 Non-Employee Directors’ Stock Incentive Plan (the “2020 Plan”) was approved by shareholders in August 2020, which replaces the 2011 Director Plan and authorizes the issuance of 200,000 shares of common stock to non-employee directors. We expect to grant each independent director $50,000 of stock on the date of each subsequent Annual Meeting.