Interim Financial Statements - Additional Information (Detail) - USD ($)	3 Months Ended	9 Months Ended		33 Months Ended
	May 31, 2016	May 31, 2016	May 31, 2015	May 31, 2016	Oct. 31, 2013
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program total cost of repurchased shares		$ 32,373,000	$ 48,451,000
Share Repurchase Program - 2014
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program total cost of repurchased shares		$ 32,400,000		$ 137,000,000
Repurchase of common stock, shares	0	1,054,687		3,206,226
Remaining authorized repurchase amount	$ 88,000,000	$ 88,000,000		$ 88,000,000
Repurchase program expiration date	Jan. 01, 2018
Maximum | Share Repurchase Program - 2013
Equity, Class of Treasury Stock [Line Items]
Amount authorized for repurchase					$ 225,000,000