Note 8 - Federal, State and Local Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2018	Jan. 31, 2017
Current tax expense:
Federal	$ 222	$ 851	$ 2,681	$ 5,424
State and local	55	166	303	506
Current tax expense	277	1,017	2,984	5,930
Deferred tax expense (benefit):
Federal	(6,014)	(282)	(6,326)	(870)
State and local	70	(326)	(79)	(387)
Deferred tax expense (benefit):	(5,944)	(608)	(6,405)	(1,257)
Income tax provision	$ (5,667)	$ 409	$ (3,421)	$ 4,673