Comprehensive Income - Components of comprehensive income that are included in Consolidated Statement of Changes in Shareholders' Equity (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013
Comprehensive Income (Loss) Note [Abstract]
Change in unrealized gains on securities during the period, before tax	$ (274)	$ 28	$ 256
Change in unrealized gains on securities during the period, tax (expense)/(benefit)	96	(10)	(90)
Change in unrealized gains on securities during the period, net of tax	(178)	18	166
Less: Gains losses realized in net income, before tax	57	(36)
Less: Gains losses realized in net income, tax (expense)/(benefit)	(20)	13
Less: Gains realized in net income amount, net of tax	37	(23)
Other comprehensive income (loss), available-for-sale securities adjustment, before tax	(217)	(8)	256
Other comprehensive income (loss), available-for-sale securities, tax (expense)/(benefit)	76	3	(90)
Other comprehensive income (loss), available-for-sale securities adjustment, net of tax	$ (141)	$ (5)	$ 166