Note 4 - Investments - Schedule of Carrying Value and Fair Value of Equity Securities (Details) - USD ($)	Apr. 30, 2024	Apr. 30, 2023
Equity securities, cost	$ 11,663,000	$ 10,169,000
Equity securities, fair value	16,344,000	14,546,000
Exchange Traded Funds [Member]
Equity securities, cost	11,663,000	10,169,000
Equity securities, gross unrealized gains	4,685,000	4,392,000
Equity securities, gross unrealized losses	(4,000)	(15,000)
Equity securities, fair value	$ 16,344,000	$ 14,546,000