Note 2 - Investments - Schedule of Assets and Liabilities (Details) - EAM Trust [Member] - USD ($) $ in Thousands		Jan. 31, 2017	Apr. 30, 2016
EAM's total assets		$ 60,354	$ 60,292
EAM's total liabilities (1)	[1]	(2,910)	(3,021)
EAM's total equity		$ 57,444	$ 57,271

[1] At January 31, 2017 and April 30, 2016, EAM's total liabilities included a payable to VLI for its accrued non-voting revenues, interest and the 90% distributable share of its non-voting profits interest of $1,921,000 and $1,750,000, respectively.