Note 2 - Investments - Securities Measured and Carried at Fair Value on Recurring Basis With Significant Unobservable Inputs (Details) $ in Thousands	Dec. 31, 2022 USD ($)		Jun. 30, 2022 USD ($)
Investments in equity securities	$ 13,264		$ 14,300
Investments in debt securities	$ 8,127	[1]	$ 10,625
Measurement Input, Price Volatility [Member]
Investments in equity securities, unobservable inputs	0.958
Investments in debt securities, unobservable input	1.051
Measurement Input, Discount Rate [Member]
Investments in debt securities, unobservable input	0.158
Valuation Technique, Option Pricing Model [Member]
Investments in equity securities	$ 26
Valuation Technique, Binomial Lattice Model [Member]
Investments in debt securities	$ 8,127

[1] Principal payments of $750,000 are due quarterly with a final maturity date in January 2026.