Note 6 - Non-operating Income - Summary of Non-operating Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Dividends and net realized gains and losses on sales of securities	$ 1,690	$ 1,324	$ 4,604	$ 4,381
Interest income	2,222	1,373	5,571	3,572
Equity in earnings of unconsolidated investments	185	34	1,941	498
Total non-operating income	$ 4,097	$ 2,731	$ 12,116	$ 8,451