Note 2 - Investments - Assets and Liabilities (Details) - EAM Trust [Member] - USD ($) $ in Thousands		Oct. 31, 2018	Apr. 30, 2018
EAM's total assets		$ 60,284	$ 60,203
EAM's total liabilities (1)	[1]	(3,303)	(3,128)
EAM's total equity		$ 56,981	$ 57,075

[1] At October 31, 2018 and April 30, 2018, EAM's total liabilities included a payable to VLI for its accrued non-voting revenues interest and non-voting profits interest of $2,317,000 and $2,113,000, respectively.