Supplementary Cash Flow Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2012
Supplemental Cash Flow Elements [Abstract]
State and local income tax payments	$ (114)	$ (120)	$ (159)
Federal income tax payments to the Parent	$ (2,254)	$ (1,877)	$ (845)