Income Taxes - Summary of Income Tax Expense/(Benefit) from Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Current:
Federal	$ 8,356	$ 693	$ 2,833
State	1,085	149	583
Foreign	4	4	5
Total current	9,445	846	3,421
Deferred:
Deferred federal	(3,222)	(11,266)	(2,442)
Deferred state	(336)	(1,233)	(245)
Total deferred	(3,558)	(12,499)	(2,687)
Total income tax expense/(benefit)	$ 5,887	$ (11,653)	$ 734