Changes in Accrued Warranty Balances (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Feb. 28, 2014		Feb. 28, 2013		Feb. 28, 2014		Feb. 28, 2013
Product Liability Contingency [Line Items]
Beginning Balance	$ 8,579		$ 15,138		$ 9,330		$ 14,751
Deductions	(4,584)	[1]	(4,908)	[1]	(16,559)	[1]	(12,895)	[1]
Provision charged to SG&A expense	3,761		3,407		14,985		11,781
Ending Balance	$ 7,756		$ 13,637		$ 7,756		$ 13,637

[1] Primarily claims paid during the year.