Accounting for Uncertainty in Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017
Change in Unrecognized Tax Benefits
Balance at beginning of year	$ 28	$ 30
Reductions for tax positions of prior years	0	(2)
Acquisitions, divestures, and other	900	0
Balance at end of year	$ 928	$ 28