Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013
Current:
Federal	$ 2,506	$ 4,253	$ 4,103
State	501	686	847
Current Income Tax Expense (Benefit), Total	3,007	4,939	4,950
Deferred:
Federal	(697)	557	131
State	(36)	70	33
Deferred Income Tax Expense (Benefit), Net of Valuation Allowance, Total	(733)	627	164
Income tax expense	$ 2,274	$ 5,566	$ 5,114