Income Taxes (Schedule Of Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
CURRENT EXPENSE
Federal	$ 23,638	$ 18,239	$ 12,663
State	4,189	3,195	1,890
Total current expense	27,827	21,434	14,553
DEFERRED EXPENSE
Federal	8,607	10,179	3,024
State	1,292	1,450	1,311
Total deferred expense	9,899	11,629	4,335
Total expense	37,726	33,063	18,888
Other comprehensive income (loss)	4,391	(4,110)	(9,510)
Total comprehensive income tax expense	$ 42,117	$ 28,953	$ 9,378