Comprehensive Income - Components of comprehensive income that are included in Consolidated Statement of Changes in Shareholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
Comprehensive Income (Loss) Note [Abstract]
Change in unrealized losses on securities, Amount Before Tax			$ (147)	$ 6
Change in unrealized losses on securities, Tax Benefit			52	(2)
Change in unrealized losses on securities, Amount Net of Tax			(95)	4
Less: Gains realized in net income, Amount Before Tax			(105)	(57)
Less: Gains realized in net income, Tax Benefit			37	20
Less: Gains realized in net income, Amount Net of Tax			(68)	(37)
Add: Losses realized in net income, Amount Before Tax			15
Add: Losses realized in net income, Tax Benefit			(5)
Add: Losses realized in net income, Amount Net of Tax			10
Other comprehensive income (loss), available-for-sale securities adjustment, Amount Before Tax			(237)	(51)
Other comprehensive income (loss), available-for-sale securities, Tax Benefit			84	18
Other comprehensive income (loss), available-for-sale securities adjustment, Amount Net of Tax	$ (127)	$ (16)	$ (153)	$ (33)