Changes in Accrued Warranty Balances (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Nov. 30, 2013		Nov. 30, 2012		Nov. 30, 2013		Nov. 30, 2012
Product Liability Contingency [Line Items]
Beginning Balance	$ 9,842		$ 14,527		$ 9,330		$ 14,751
Deductions	(7,179)	[1]	(4,082)	[1]	(11,975)	[1]	(7,987)	[1]
Provision charged to SG&A expense	5,916		4,693		11,224		8,374
Ending Balance	$ 8,579		$ 15,138		$ 8,579		$ 15,138

[1] Primarily claims paid during the year.