Investments (Detail Textuals 1) (USD $)	3 Months Ended
	Jul. 31, 2012		Jul. 31, 2011	Apr. 30, 2012
Investment in Unconsolidated Entities, Equity Method Investment [Line Items]
Value Line Investment in EAM Trust (1)	$ 57,306,000	[1]		$ 56,331,000	[1]
Fair value of contributed capital at inception	55,805,000			55,805,000
Cash and liquid securities in excess of working capital requirements contributed to capital account	5,820,000			5,820,000
Non-voting revenue interest	1,394,000		1,491,000
Net income	1,776,000		2,076,000
Total assets	82,927,000			84,369,000
Total liabilities	50,295,000			52,055,000
EULAV Asset Management LLC
Investment in Unconsolidated Entities, Equity Method Investment [Line Items]
Total investment management fees earned from value line funds	3,080,000		3,301,000
Distribution and service (12b-1)	891,000		928,000
Other income			4,000
Total investment management fee waivers	179,000		230,000
Distribution and service fee waivers (12b-1)	541,000		618,000
Non-voting revenue interest	1,394,000		1,491,000
Net income	158,000		162,000
Total assets	58,838,000		58,091,000
Total liabilities	2,472,000		1,471,000
Payable to VLI for its accrued non-voting revenues and non-voting profits interests	1,482,000
Total equity	56,366,000		56,620,000
Quarterly obligation for distributions to all interest holders	$ 1,539,000

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