Note L - Commitments and Contingencies (Details Textual) - USD ($)	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Letters of Credit Outstanding, Amount	$ 250,000
Lessee, Operating Lease, Liability, to be Paid, Total	85,448,000
Operating Lease, Expense	8,000,000.0	$ 6,900,000	$ 6,700,000
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	7,300,000
Non-cancelable [Member]
Lessee, Operating Lease, Liability, to be Paid, Total	25,200,000
Reasonably Assured [Member]
Lessee, Operating Lease, Liability, to be Paid, Total	60,200,000
Owned or Controlled by One Preferred Shareholder [Member]
Lessee, Operating Lease, Liability, to be Paid, Total	$ 23,000,000,000
Minimum [Member]
Lessee, Operating Lease, Term of Contract (Year)	3 years
Minimum [Member] | Dealership Leases [Member]
Lessee, Operating Lease, Term of Contract (Year)	3 years
Maximum [Member]
Lessee, Operating Lease, Term of Contract (Year)	10 years
Maximum [Member] | Dealership Leases [Member]
Lessee, Operating Lease, Term of Contract (Year)	5 years