Changes in Accrued Warranty Balances (Detail) - USD ($) $ in Thousands		12 Months Ended
		May 31, 2021	May 31, 2020	May 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Beginning Balance		$ 11,106	$ 10,414	$ 11,721
Deductions	[1]	(25,817)	(20,762)	(22,262)
Provision charged to expense		27,886	21,454	20,955
Ending Balance		$ 13,175	$ 11,106	$ 10,414

[1] Primarily claims paid during the year.