Note 8 - Federal, State and Local Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Federal	$ 1,556	$ 1,351	$ 3,022	$ 2,664
State and local	325	344	594	697
Current tax expense	1,881	1,695	3,616	3,361
Federal	77	(59)	118	30
State and local	(134)	(15)	(343)	(4)
Deferred tax expense (benefit):	(57)	(74)	(225)	26
Income tax provision	$ 1,824	$ 1,621	$ 3,391	$ 3,387