Note 7 - Federal, State and Local Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Current tax expense:
Federal	$ 3,853	$ 6,360	$ 3,799
State and local	365	469	219
Current tax expense	4,218	6,829	4,018
Deferred tax expense (benefit):
Federal	(7,021)	(1,299)	(839)
State and local	(37)	(412)	(462)
Deferred tax expense (benefit):	(7,058)	(1,711)	(1,301)
Income tax provision	$ (2,840)	$ 5,118	$ 2,717