Derivative Instruments - Fair Values of Derivative Instruments (Detail) - USD ($) $ in Millions	Nov. 30, 2021	Aug. 31, 2021
Designated as Hedging Instrument | Accounts Payable and Accrued Liabilities
Derivatives Fair Value [Line Items]
Liability Derivatives	$ 12.8	$ 10.3
Designated as Hedging Instrument | Accounts Receivable
Derivatives Fair Value [Line Items]
Asset Derivatives		0.1
Designated as Hedging Instrument | Foreign Exchange Contracts | Accounts Payable and Accrued Liabilities
Derivatives Fair Value [Line Items]
Liability Derivatives	5.7	0.3
Designated as Hedging Instrument | Foreign Exchange Contracts | Accounts Receivable
Derivatives Fair Value [Line Items]
Asset Derivatives		0.1
Designated as Hedging Instrument | Interest rate swap contracts | Accounts Payable and Accrued Liabilities
Derivatives Fair Value [Line Items]
Liability Derivatives	7.1	10.0
Not Designated as Hedging Instrument | Foreign Exchange Contracts | Accounts Payable and Accrued Liabilities
Derivatives Fair Value [Line Items]
Liability Derivatives	$ 0.1	$ 0.1