Note 2 - Investments - Securities Measured and Carried at Fair Value on Recurring Basis With Significant Unobservable Inputs (Details) $ in Thousands	Mar. 31, 2023 USD ($)		Jun. 30, 2022 USD ($)
Statement [Line Items]
Investments in equity securities	$ 13,184		$ 14,300
Investments in debt securities	$ 7,649	[1]	$ 10,625
Measurement Input, Discount Rate [Member]
Statement [Line Items]
Investments in debt securities, unobservable input	0.150
Valuation Technique, Option Pricing Model [Member]
Statement [Line Items]
Investments in equity securities	$ 222
Investments in debt securities, unobservable input	101,500
Valuation Technique, Binomial Lattice Model [Member]
Statement [Line Items]
Investments in debt securities, unobservable input	0.998
Investments in debt securities	$ 7,649

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