Accounts Payable and Accrued Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Nov. 30, 2014	Aug. 31, 2014	Nov. 30, 2013	Aug. 31, 2013
Accounts Payable and Accrued Liabilities [Line Items]
Trade payables	$ 223,093	$ 204,744
Other accrued liabilities	62,009	66,421
Accrued payroll and related liabilities	53,432	64,959
Accrued maintenance	15,510	14,329
Accrued warranty	8,896	9,340	11,479	12,128
Other	7,932	3,787
Income taxes payable	3,637	19,709
Accounts payable and accrued liabilities	$ 374,509	$ 383,289