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		Jan. 31, 2022	Apr. 30, 2021
Assets		$ 129,752	$ 121,136
Liabilities		50,351	54,123
EAM Trust [Member]
Assets		65,144	64,197
Liabilities	[1]	7,910	6,870
EAM Trust [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Assets	[2]	60,882	60,977
Liabilities		0	0
Value Line Maximum Exposure to Loss		$ 60,882	$ 60,977

[1] At October 31, 2021 and April 30, 2021, EAM's total liabilities included a payable to VLI for its accrued non-voting revenues interest and non-voting profits interest of $4,830,000 and $4,664,000, respectively.

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