Summary of Available-for-Sale Debt Securities in Unrealized Loss Position and Included in Accumulated Other Comprehensive (Loss), Aggregated by Length of Time Investments (Detail) - USD ($) $ in Thousands	May 31, 2023	May 31, 2022
Investments, Debt and Equity Securities [Abstract]
Total investments with unrealized losses, fair value	$ 24,245	$ 22,702
Unrealized losses with a loss position for less than 12 months, fair value	6,285	16,273
Unrealized losses with a loss position for more than 12 months, fair value	17,960	6,429
Total investments with unrealized losses, gross unrealized losses	(1,855)	(1,342)
Unrealized losses with a loss position for less than 12 months, gross unrealized losses	(72)	(543)
Unrealized losses with a loss position for more than 12 months, gross unrealized losses	$ (1,783)	$ (799)