Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 74,861	$ 83,688	$ 63,141
Other comprehensive income (loss) net of tax:
Change in pension benefits, net of deferred taxes of $(573), $190 and $50, respectively	(1,682)	(422)	88
Total Comprehensive Income	$ 73,179	$ 83,266	$ 63,229