Note 7 - Non-operating Income - Summary of Non-operating Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Equity in earnings of unconsolidated investments	$ 14	$ 3,019	$ 5,320	$ 8,448
Dividends and net realized gains on sales of securities	2,365	2,084	6,242	5,997
Interest income	1,020	1,375	3,683	4,425
Total non-operating income	$ 3,399	$ 6,478	$ 15,245	$ 18,870