Investments - Equity Method Investment (Detail Textuals 1) - USD ($)		Jan. 31, 2016	Apr. 30, 2015
Schedule of Equity Method Investments [Line Items]
Investment in EAM Trust		$ 58,079,000	$ 58,048,000
EAM Trust
Schedule of Equity Method Investments [Line Items]
Investment in EAM Trust	[1]	58,079,000	58,048,000
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

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