SCHEDULE II - Valuation and Qualifying Accounts (Detail) - Allowance for Doubtful Accounts - USD ($) $ in Thousands	12 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2019
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 1,521	$ 1,150	$ 632
Charged to Costs and Expenses	(254)	580	659
Uncollectable Accounts Charged to Allowance	(659)	(209)	(141)
Balance at End of Period	$ 608	$ 1,521	$ 1,150