Note 4 - Marketable Equity Securities (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Investment Income, Dividend	$ 1,448,000	$ 1,266,000	$ 1,309,000
Equity Securities, FV-NI, Total	7,373,000	10,221,000
Equity Securities, FV-NI, Unrealized Loss	$ 2,419,000	$ 4,967,000
Margin Account Borrowings [Member]
Debt, Weighted Average Interest Rate	0.68%	0.75%
Margin Account Borrowings [Member] | Accrued Expenses and Other Liabilities [Member]
Short-term Debt, Total	$ 1,214,000	$ 11,251,000