Estimated Fair Values of Assets Acquired and Liabilities Assumed (Detail) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2013	Aug. 31, 2012	May 31, 2012	Aug. 24, 2011
Business Acquisition [Line Items]
Total cash consideration				$ 10,673
Preliminary purchase price allocation:
Accounts receivable		972		542
Rental and lease equipment	235,568		243,173	15,896
Deferred tax liability				(2,092)
Deferred revenue				(479)
Net assets acquired				13,867
Bargain purchase gain, net of deferred taxes of $2,092				$ (3,194)