Derivative Instruments - Fair Values of Derivative Instruments (Detail) - USD ($) $ in Millions	Feb. 29, 2024	Aug. 31, 2023
Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Asset Derivatives	$ 37.4	$ 37.4
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Accounts Receivable, after Allowance for Credit Loss	Accounts Receivable, after Allowance for Credit Loss
Liability Derivatives	$ 0.2	$ 0.2
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Accounts Payable and Accrued Liabilities
Designated as Hedging Instrument | Foreign Exchange Contracts
Derivatives Fair Value [Line Items]
Asset Derivatives	$ 5.3	$ 2.5
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Accounts Receivable, after Allowance for Credit Loss	Accounts Receivable, after Allowance for Credit Loss
Liability Derivatives	$ 0.1	$ 0.1
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities
Designated as Hedging Instrument | Interest rate swap contracts
Derivatives Fair Value [Line Items]
Asset Derivatives	$ 32.1	$ 34.9
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Accounts Receivable, after Allowance for Credit Loss	Accounts Receivable, after Allowance for Credit Loss
Liability Derivatives	$ 0.1	$ 0.1
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Accounts Payable and Accrued Liabilities
Not Designated as Hedging Instrument | Foreign Exchange Contracts
Derivatives Fair Value [Line Items]
Asset Derivatives		$ 0.5
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Accounts Receivable, after Allowance for Credit Loss
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Accounts Payable and Accrued Liabilities