Note 5 - Non-operating Income - Summary of Non-operating Income (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Equity in earnings of unconsolidated investments		$ 589,000	$ 2,015,000	$ 477,000
Dividends and net realized gains or losses on the sale of securities		7,973,000	6,262,000	5,530,000
Interest income		10,104,000	8,383,000	5,134,000
Gain on sale of unconsolidated company	$ 1,024,000	1,024,000	(0)	(0)
Total non-operating income		$ 19,690,000	$ 16,660,000	$ 11,141,000