Interim Financial Statements - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended	65 Months Ended
	Sep. 02, 2018	Feb. 28, 2019	Feb. 28, 2019	Feb. 28, 2019	Jan. 31, 2019	Jan. 30, 2019
Accounting Standards Update 2014-09
Equity, Class of Treasury Stock [Line Items]
Increase to retained earnings	$ 5.5
Share Repurchase Program - 2013
Equity, Class of Treasury Stock [Line Items]
Remaining authorized repurchase amount		$ 100.0	$ 100.0	$ 100.0	$ 100.0	$ 88.0
Stock repurchased during period, shares		0	0
Stock repurchase program total cost of repurchased shares				$ 137.0
Repurchase of common stock, shares				3,206,226