Note 2 - Investments - Unrealized Gains and Losses (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Statement [Line Items]
Net gains and losses recognized during the period on equity securities		$ 270	$ (3,049)	$ (2,599)	$ (3,098)
Less: Net gains and losses recognized during the period on equity securities sold during the period		(13)	(5)	(13)	179
Unrealized gains and losses recognized during the reporting period on equity securities still held at the reporting date (1)	[1]	$ 283	$ (3,044)	$ (2,586)	$ (3,277)

[1] Includes $1.8 million of net losses for the nine months ended March 31, 2023, as a result of the measurement alternative. There were no net gains (losses) as a result of the measurement alternative for the three months ended March 31, 2023, or for the three and nine months ended March 31, 2022.