Changes in Accrued Warranty Balances (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Feb. 28, 2021	Feb. 29, 2020	Feb. 28, 2021	Feb. 29, 2020
Commitments And Contingencies Disclosure [Abstract]
Beginning Balance		$ 12,050	$ 10,555	$ 11,106	$ 10,414
Deductions	[1]	(4,745)	(4,622)	(18,327)	(16,002)
Provision charged to expense		5,473	4,804	19,999	16,325
Ending Balance		$ 12,778	$ 10,737	$ 12,778	$ 10,737

[1] Primarily claims paid during the year.