Note 3 - Variable Interest Entity - Total Assets, the Maximum Exposure to Loss, and Value of the Assets and Liabilities in EAM (Details) - USD ($)		Oct. 31, 2017	Apr. 30, 2017
Equity Method Investments		$ 58,588,000	$ 58,223,000
EAM Trust [Member]
VIE Assets		61,204,000	60,432,000
Equity Method Investments	[1]	58,588,000	58,223,000
Value Line Liabilities
Value Line Liabilities		$ 58,588,000	$ 58,223,000

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