Business Segments - Disclosure of reportable segment information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Segment Reporting Information [Line Items]
Total revenues	$ 35,840	$ 36,609	$ 48,667
Depreciation and amortization	1,552	724	593
Gain from deconsolidation of subsidiaries			50,510	[1]
Revenues and profits interests in EAM Trust	6,260	5,890	2,355
Income before income taxes	10,506	11,298	61,463
Reportable business segments
Segment Reporting Information [Line Items]
Revenues from external customers			48,667
Intersegment revenues			7
Total revenues for reportable segments			48,674
Elimination of intersegment revenues			(7)
Total revenues			48,667
Depreciation and amortization			593
Depreciation related to corporate assets			(3)
Gain from deconsolidation of subsidiaries			50,510
Income from securities transactions			6
Segment profit (loss) from operations			8,536	[2]
Profit for reportable segments			59,052
Revenues and profits interests in EAM Trust			2,355
Income from securities transactions related to corporate assets			59
Depreciation related to corporate assets			(3)
Income before income taxes			61,463
Reportable business segments | Publishing
Segment Reporting Information [Line Items]
Revenues from external customers			37,974
Intersegment revenues			7
Total revenues for reportable segments			37,981
Elimination of intersegment revenues			(7)
Total revenues			37,974
Depreciation and amortization			579
Depreciation related to corporate assets			(3)
Gain from deconsolidation of subsidiaries				[1]
Income from securities transactions
Segment profit (loss) from operations			8,984	[2]
Profit for reportable segments			8,984
Reportable business segments | Investment Management
Segment Reporting Information [Line Items]
Revenues from external customers			10,693
Intersegment revenues
Total revenues for reportable segments			10,693
Elimination of intersegment revenues
Total revenues			10,693
Depreciation and amortization			14
Depreciation related to corporate assets
Gain from deconsolidation of subsidiaries			50,510	[1]
Income from securities transactions			6
Segment profit (loss) from operations			(448)	[2]
Profit for reportable segments			$ 50,068

[1] Represents the gain of $50,510,000 from deconsolidation of the asset management and Value Line Mutual Fund Distribution subsidiaries.

[2] Included in the Investment Management business segment in fiscal 2011 are expenses of $3,764,000 related to the Company's restructure of its Investment Management business segment, $914,000 of expenses related to its exit lease obligation for the office space previously occupied by EAM LLC, and non-cash post-employment compensation expense of $1,770,000 related to the value of the voting profits interest in EAM granted by VLI to a former employee of the Company who is presently the CEO of EAM. Fiscal 2011 Investment Management segment expenses included the reversal of $1,767,000 of previously recorded expenses associated with the Provision for Settlement due to a change in estimated costs to administer the Fair Fund.