Note 8 - Federal, State and Local Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Federal	$ 1,143	$ 871	$ 2,133	$ 1,605
State and local	319	72	615	160
Current tax expense	1,462	943	2,748	1,765
Federal	(38)	5	(54)	5
State and local	195	17	272	(254)
Deferred tax expense (benefit):	157	22	218	(249)
Income tax provision	$ 1,619	$ 965	$ 2,966	$ 1,516