Note 2 - Investments - Income From Securities Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2023	Oct. 31, 2022
Dividend income	$ 133	$ 141	$ 278	$ 254
Interest income	487	158	876	201
Investment gains/(losses) recognized on sales of equity securities during the period	(14)	3	(3)	5
Unrealized gains/(losses) recognized on equity securities held at the end of the period	(1,685)	(577)	(1,475)	(434)
Other	0	7	0	0
Total investment gains/(losses)	$ (1,079)	$ (268)	$ (324)	$ 26