Interim Financial Statements - Additional Information (Detail) - USD ($)		3 Months Ended	62 Months Ended
	Sep. 01, 2018	Nov. 30, 2018	Nov. 30, 2018	Jan. 31, 2019
Accounting Standards Update 2014-09
Equity, Class of Treasury Stock [Line Items]
Increase to retained earnings	$ 5,500,000
Share Repurchase Program - 2013
Equity, Class of Treasury Stock [Line Items]
Remaining authorized repurchase amount		$ 88,000,000	$ 88,000,000
Stock repurchased during period, shares		0
Stock repurchase program total cost of repurchased shares			$ 137,000,000
Repurchase of common stock, shares			3,206,226
Subsequent Event | Share Repurchase Program - 2013
Equity, Class of Treasury Stock [Line Items]
Remaining authorized repurchase amount				$ 100,000,000