Derivative Instruments - Effects of Cash Flow Hedges Included in Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended
	Nov. 30, 2021	Nov. 30, 2020
Derivative [Line Items]
Revenue	$ 550.7	$ 403.0
Cost of revenue	503.1	362.3
Interest and foreign exchange	12.6	11.1
Sales
Derivative [Line Items]
Amount of gain (loss) on cash flow hedge activity	(0.2)	(0.3)
Interest and Foreign Exchange
Derivative [Line Items]
Amount of gain (loss) on cash flow hedge activity	$ (1.3)	$ (1.3)