Note 4 - Summary of Unrealized and Realized Gains and Losses Recognized in Net Income on Equity Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Equity Securities [Abstract]
Net (losses) gains recognized during the period on equity securities	$ (621)	$ 2,714	$ 538
Less: Net gains recognized during the period on equity securities sold during the period	405	1,788	585
Net unrealized (losses) gains recognized during the reporting period on equity securities still held at the reporting date	$ (1,026)	$ 926	$ (47)