Note B - Summary of Significant Accounting Policies - Property and Equipment, Estimated Useful Lives (Details)	9 Months Ended
	Jan. 31, 2022
Minimum [Member] | Furniture, Fixtures and Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)	3 years
Minimum [Member] | Leasehold Improvements [Member]
Property, Plant and Equipment, Useful Life (Year)	5 years
Minimum [Member] | Building and Building Improvements [Member]
Property, Plant and Equipment, Useful Life (Year)	18 years
Maximum [Member] | Furniture, Fixtures and Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)	7 years
Maximum [Member] | Leasehold Improvements [Member]
Property, Plant and Equipment, Useful Life (Year)	15 years
Maximum [Member] | Building and Building Improvements [Member]
Property, Plant and Equipment, Useful Life (Year)	39 years