Note 5 - Variable Interest Entity - Schedule of Total Assets, the Maximum Exposure to Loss, Value of the Assets and Liabilities in EAM (Details) - USD ($)		Apr. 30, 2017	Apr. 30, 2016
Equity Method Investments		$ 58,223,000	$ 57,942,000
EAM Trust [Member]
Value Line Liabilities
Value Line Liabilities		58,223,000	57,942,000
VIE Assets		60,432,000	60,292,000
Equity Method Investments	[1]	$ 58,223,000	$ 57,942,000

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