Note 8 - Federal, State and Local Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2020	Jan. 31, 2019
Federal	$ 1,347	$ 513	$ 3,480	$ 2,118
State and local	300	173	915	333
Current tax expense	1,647	686	4,395	2,451
Federal	154	429	100	434
State and local	(2)	197	270	(57)
Deferred tax expense (benefit):	152	626	370	377
Income tax provision	$ 1,799	$ 1,312	$ 4,765	$ 2,828