Other Income and Other Expenses (Schedule of Interest Income and Expense of Continuing Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Other Income and Expenses [Abstract]
Interest income	$ 2,225	$ 4,505	$ 10,251	$ 9,002
Foreign currency gains (losses), net	105	(124)	114	(127)
Other, net	409	83	1,497	131
Other income (expense), net	$ 2,739	$ 4,464	$ 11,862	$ 9,006