Note 8 - Federal, State and Local Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Jan. 31, 2024	Apr. 30, 2023
Deferred tax liability	$ 12,822	$ 13,129
Domestic Tax Authority [Member]
Deferred gain on deconsolidation of EAM	10,669	10,669
Deferred non-cash post-employment compensation	(372)	(372)
Depreciation and amortization	70	59
Unrealized gain/(loss) on fixed income securities held for sale	(7)	99
Unrealized gain on equity securities	895	919
Right of Use Asset	(154)	(174)
Deferred charges	(133)	(136)
Other	(461)	(432)
Deferred tax liability	10,507	10,632
State and Local Jurisdiction [Member]
Deferred gain on deconsolidation of EAM	2,252	2,062
Deferred non-cash post-employment compensation	(78)	(72)
Depreciation and amortization	15	125
Unrealized gain/(loss) on fixed income securities held for sale	(2)	19
Unrealized gain on equity securities	189	178
Other	(61)	185
Deferred tax liability	$ 2,315	$ 2,497