Note 6 - Components of comprehensive income that are included in Consolidated Statement of Changes in Shareholders' Equity (Details) - USD ($)	3 Months Ended
	Jul. 31, 2016	Jul. 31, 2015
Change in unrealized gains on securities	$ 238,000	$ (142,000)
Change in unrealized gains on securities	(84,000)	(50,000)
Change in unrealized gains on securities	154,000	(92,000)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent	238,000	(142,000)
Other comprehensive income (loss), available-for-sale securities, tax (expense)/(benefit)	(84,000)	(50,000)
Other comprehensive income (loss), available-for-sale securities adjustment, net of tax	154,000	(92,000)
Change in unrealized gains on securities	84,000	50,000
Other comprehensive income (loss), available-for-sale securities, tax (expense)/(benefit)	$ 84,000	$ 50,000