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		Oct. 31, 2020	Apr. 30, 2020
Assets		$ 110,837	$ 109,728
Liabilities		51,609	56,189
EAM Trust [Member]
Assets		63,549	61,335
Liabilities	[1]	6,529	4,192
EAM Trust [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Assets	[2]	60,351	59,165
Liabilities
Value Line Maximum Exposure to Loss		$ 60,351	$ 59,165

[1] At October 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 $4,165,000 and $2,949,000, respectively.

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