Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Apr. 30, 2020
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 9,940		$ 8,907
Unrecognized tax benefits that would impact effective tax rate	7,875
Accrued interest and penalties related to unrecognized tax benefits	420		$ 354
Net interest and penalties included in income tax expense	66	$ 57
Expected decrease in unrecognized tax benefits	$ 1,800