INVESTMENT ASSETS, NET (Details) - USD ($)	3 Months Ended
	Jul. 31, 2021	Jul. 31, 2020	Apr. 30, 2021
INVESTMENT ASSETS, NET
Land held for long-term investment	$ 9,775,000		$ 9,775,000
Buildings	10,003,000		10,003,000
Less accumulated depreciation	(6,299,000)		(6,196,000)
Buildings, net	3,704,000		3,807,000
Total	13,479,000		$ 13,582,000
Depreciation on buildings	$ 103,000	$ 105,000