Note 3 - Variable Interest Entity - Total Assets, the Maximum Exposure to Loss, and Value of the Assets and Liabilities in EAM (Details) - USD ($) $ in Thousands		Jul. 31, 2020	Apr. 30, 2020
Assets		$ 110,891	$ 109,728
Liabilities		54,135	56,189
EAM Trust [Member]
Assets		62,563	61,335
Liabilities	[1]	5,672	4,192
EAM Trust [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Assets	[2]	59,744	59,165
Liabilities
Value Line Maximum Exposure to Loss		$ 59,744	$ 59,165

[1] At July 31, 2020 and April 30, 2020, EAM's total liabilities included a payable to VLI for its accrued non-voting revenues interest and non-voting profits interest of $3,607,000 and $2,949,000, respectively.

[2] Reported within Long-Term Assets on Consolidated Balance Sheets.