Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Thousands	Feb. 28, 2017	Nov. 30, 2016	Aug. 31, 2016	Feb. 29, 2016	Nov. 30, 2015	Aug. 31, 2015
Accounts Payable and Accrued Liabilities [Line Items]
Trade payables	$ 173,441		$ 182,334
Other accrued liabilities	68,594		71,260
Accrued payroll and related liabilities	65,042		76,058
Accrued maintenance	18,404		18,646
Accrued warranty	14,582	$ 11,737	12,159	$ 12,147	$ 11,609	$ 11,512
Income taxes payable	27,564		3,991
Other	4,694		5,306
Accounts payable and accrued liabilities	$ 372,321		$ 369,754