Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Statement Of Other Comprehensive Income [Abstract]
Net income	$ 6,619	$ 6,925	$ 37,782
Other comprehensive income, net of tax:
Change in unrealized gains on securities, net of taxes	166	22	65
Other comprehensive income	166	22	65
Comprehensive income	$ 6,785	$ 6,947	$ 37,847