Investments (Detail Textuals) - USD ($)		12 Months Ended
		Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013
Schedule of Available-for-sale Securities [Line Items]
Aggregate cost of equity securities available for sale		$ 9,470,000	$ 8,847,000
Fair value of equity securities		9,632,000	9,226,000
Capital gain distribution from ETFs	[1]	57,000	36,000
Increase (decrease) in gross unrealized gains on equity securities classified as available-for-sale		(217,000)	(8,000)	$ 256,000
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		105,000	246,000
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Aggregate cost of equity securities available for sale		9,470,000	8,847,000
Fair value of equity securities		9,632,000	9,226,000
Increase (decrease) in gross unrealized gains on equity securities classified as available-for-sale		(217,000)	(8,000)
Deferred taxes on unrealized gains on securities		$ 76,000	$ 3,000
Proceeds from maturities and sales of government debt securities
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		$ 162,000	$ 380,000
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Deferred Tax Expense (Benefit)		$ 57,000	$ 134,000

[1] Capital gain distributions of $57,000 and $36,000 which were reclassified from Accumulated Other Comprehensive Income in the Consolidated Balance Sheets to the Consolidated Statements of Income in fiscal 2015 and 2014, respectively.