Note 5 - Non-operating Income - Summary of Non-operating Income (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2024	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Dividends and net realized gains and losses on sales of securities		$ 2,089,000	$ 1,683,000	$ 5,971,000	$ 5,462,000
Interest income		2,676,000	2,603,000	7,388,000	7,790,000
Equity in earnings/(loss) of unconsolidated investments		(105,000)	(62,000)	512,000	589,000
Gain on sale of unconsolidated company	$ 1,024,000	0	0	(0)	1,024,000
Total non-operating income		$ 4,660,000	$ 4,224,000	$ 13,871,000	$ 14,865,000