Revenue Recognition (Deferred Revenue) (Details) - POM - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018
Movement in Deferred Revenue [Roll Forward]
Balance, end of the period	$ 148,600
Deferred Revenue
Movement in Deferred Revenue [Roll Forward]
Balance, beginning of the period	212,511	$ 218,274
Amounts deferred	4,222	3,459
Amounts recognized on previous deferrals	(68,088)	(71,074)
Balance, end of the period	148,645	150,659
Deferred Wages
Movement in Deferred Revenue [Roll Forward]
Balance, beginning of the period	27,306	32,683
Amounts deferred	29	80
Amounts recognized on previous deferrals	(9,430)	(10,752)
Balance, end of the period	$ 17,905	$ 22,011