Related Party Transactions (Detail Textuals 1) (USD $) In Millions, unless otherwise specified	May 31, 2012	Dec. 31, 2011 Value Line Convertible Fund	May 31, 2012 Value Line New York Tax Exempt Trust	May 31, 2012 Value Line Tax Exempt Fund	Mar. 31, 2013 Value Line Core Bond Fund
Related Party Transaction [Line Items]
Assets under management	$ 20	$ 20	$ 15	$ 90	$ 100

The carrying amount of assets an investment adviser manages on behalf of investors.

No definition available.

Name:	us-gaap_AssetsUnderManagementCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant