Schedule II - Valuation and Qualifying Accounts (Detail) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 17,875	$ 14,032	$ 15,682
Charges to Cost and Expenses	1,642	886	5,170
Charges to Other Accounts	8,119	3,939
Deductions	(2,463)	(982)	(6,820)
Balance at End of Period	$ 25,173	$ 17,875	$ 14,032