Note 7 - Federal, State and Local Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017
Federal	$ 2,964	$ 3,853	$ 6,360
State and local	600	365	469
Current tax expense	3,564	4,218	6,829
Federal	(650)	(7,021)	(1,299)
State and local	1,162	(37)	(412)
Deferred tax expense (benefit):	512	(7,058)	(1,711)
Income tax provision	$ 4,076	$ (2,840)	$ 5,118