Note I - Capital Stock (Details Textual) - USD ($)	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021
Common Stock, Shares Authorized (in shares)	50,000,000	50,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized (in shares)	1,000,000	1,000,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.01	$ 0.01
Preferred Stock, Shares Issued, Total (in shares)	0	0
Subsidiaries [Member]
Preferred Stock, Par or Stated Value Per Share (in dollars per share)	$ 1.00
Preferred Stock, Shares Issued, Total (in shares)	500,000
Preferred Stock, Dividend Rate, Percentage	8.00%
Preferred Stock Right of Shareholder, Amount of Shares (in shares)	400,000
Preferred Stock, Right to Shareholder Value of Redeemed Stock	$ 400,000