Related Party Transactions (Detail Textuals) (USD $)	3 Months Ended			3 Months Ended			1 Months Ended	3 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Apr. 30, 2012	Jul. 31, 2012 EULAV Asset Management LLC	Jul. 31, 2011 EULAV Asset Management LLC	Apr. 30, 2012 EULAV Asset Management LLC	May 31, 2011 Value Line Inc	Jul. 31, 2012 Value Line Inc	Jul. 31, 2011 Value Line Inc	Jul. 31, 2012 Arnold Bernhard and Co Inc	Jul. 31, 2011 Arnold Bernhard and Co Inc	Apr. 30, 2012 Arnold Bernhard and Co Inc
Related Party Transaction [Line Items]
Total assets of value line funds managed by EAM				$ 2,000,000,000	$ 2,150,000,000
Percentage of assets decreased in funds				6.00%
Percentage of non voting profits interests due each quarter from EAM								90.00%
Non voting profits interest in variable entity not yet paid				1,482,000		497,000
Revenues and profits interests in EAM Trust	1,473,000	1,572,000						1,473,000	1,572,000
Non-voting revenue interest	1,394,000	1,491,000		1,394,000	1,491,000			1,394,000	1,491,000
Non-voting profits interest	79,000	81,000						79,000	81,000
Rental and accounting and other administrative support service income							44,000
Reimbursed income										0	101,000
Receivables due from Parent	40,000									40,000		0
Prepaid and refundable income taxes	$ 163,000		$ 779,000							$ 101,000		$ 530,000
Percentage of ownership of parent company	87.20%