Comprehensive Income - Components of comprehensive income that are included in the Consolidated Statement of Changes in Shareholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Comprehensive Income (Loss) Note [Abstract]
Change in unrealized gains (losses) on securities during the period, before tax	$ 255	$ 24	$ 32
Change in unrealized gains (losses) on securities during the period, tax expense	(195)	(33)	(14)
Change in unrealized gains (losses) on securities during the period, tax benefit	106	24	3
Change in unrealized gains (losses) on securities during the period, net of tax	166	15	21
Add: Losses realized in net income, before tax		11	68
Add: Losses realized in net income, tax expense		(4)	(24)
Add: Losses realized in net income, tax benefit
Add: Losses realized in net income, net of tax		7	44
Other comprehensive income (loss), available-for-sale securities adjustment, before tax	255	35	100
Other comprehensive income (loss), available-for-sale securities, tax expense	(195)	(37)	(38)
Other comprehensive income (loss), available-for-sale securities, tax benefit	106	24	3
Other comprehensive income (loss), available-for-sale securities adjustment, net of tax	$ 166	$ 22	$ 65