Revenues from External Customers and Long-Lived Assets, by Geographical Areas (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended										12 Months Ended
	May 31, 2013		Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	May 31, 2012		Feb. 29, 2012	Nov. 30, 2011	Aug. 31, 2011	May 31, 2013		May 31, 2012		May 31, 2011
Revenues:
U.S.											$ 211,745	[1]	$ 214,354	[1]	$ 199,861	[1]
Other											36,986	[1],[2]	34,200	[1],[2]	28,868	[1],[2]
Total revenues	60,366		64,672	65,192	58,501	68,182		60,079	61,643	58,650	248,731	[1]	248,554	[1]	228,729	[1]
Net Long Lived Assets:
U.S.	198,956	[3]				207,449	[3]				198,956	[3]	207,449	[3]	176,268	[3]
Other	49,726	[2],[3]				49,595	[2],[3]				49,726	[2],[3]	49,595	[2],[3]	33,491	[2],[3]
Total net long-lived assets	$ 248,682	[3]				$ 257,044	[3]				$ 248,682	[3]	$ 257,044	[3]	$ 209,759	[3]

[1] Revenues by country are based on the location of shipping destination, whether the order originates in the U.S. parent or a foreign subsidiary.

[2] Other consists of other foreign countries. Each foreign country individually accounts for less that 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 and 2011 should not have included goodwill or intangibles (which totaled $4,310 at May 31, 2012 and $4,323 at May 31, 2011) and, accordingly, such amount has been excluded from the May 31, 2012 and 2011 balances, respectively, displayed in the table above.