Investments - Composition of income from securities transactions (Details 1) - USD ($) $ in Thousands		12 Months Ended
		Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013
Investment Income, Net [Abstract]
Dividend income		$ 157	$ 147	$ 124
Interest income		3	5	$ 4
Capital gain distribution from ETFs	[1]	57	$ 36
Exchange loss		$ (16)
Interest expense			$ (5)
Other		$ (75)	(5)	$ (2)
Total income/(loss) from securities transactions and other, net		$ 126	$ 178	$ 126

[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.