Investments - Equity Method Investment (Detail Textuals 1) (USD $)	6 Months Ended
	Oct. 31, 2013		Apr. 30, 2013
Schedule of Equity Method Investments [Line Items]
Investment in EAM Trust	$ 57,761,000		$ 57,511,000
EAM Trust
Schedule of Equity Method Investments [Line Items]
Investment in EAM Trust	57,761,000	[1]	57,511,000	[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 profits interest ("Profits Interest")	50.00%
Payable to VLI for its accrued non-voting revenues and non-voting profits interests	$ 1,835,000		$ 1,621,000

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