Revenues from External Customers and Long-Lived Assets, by Geographical Areas (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Feb. 28, 2013		Feb. 29, 2012		Feb. 28, 2013		Feb. 29, 2012		May 31, 2012
Revenues:
U.S.	$ 56,069	[1]	$ 51,986	[1]	$ 161,611	[1]	$ 155,563	[1]
Other	8,603	[1],[2]	8,093	[1],[2]	26,754	[1],[2]	24,809	[1],[2]
Total revenues	64,672	[1]	60,079	[1]	188,365	[1]	180,372	[1]
Net Long-Lived Assets:
U.S.	198,290	[3]			198,290	[3]			207,449	[3]
Other	51,113	[2],[3]			51,113	[2],[3]			49,595	[2],[3]
Total net long-lived assets	$ 249,403	[3]			$ 249,403	[3]			$ 257,044	[3]

[1] Revenues by country are based on the location of shipping destination, and not whether the order originates in the United States parent or a foreign subsidiary.

[2] Other consists of foreign countries. Each foreign country individually accounts for less than 10% of the total revenues and long-lived assets.

[3] Net long-lived assets include rental and lease equipment and other property, net of accumulated depreciation and amortization. Subsequent to the issuance of the May 31, 2012 consolidated financial statements, we determined that, for geographic disclosure purposes, the previously reported amount of net long-lived assets as of May 31, 2012 should not have included goodwill and intangibles (which totaled $4,310 at that date) and, accordingly, such amount has been excluded from the May 31, 2012 balance displayed in the table above.