Accumulated Other Comprehensive Loss - Amounts Reclassified out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Feb. 29, 2024	Feb. 28, 2023	Feb. 29, 2024	Feb. 28, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest and foreign exchange	$ 24.6	$ 21.6	$ 47.8	$ 41.2
Total before tax	(38.9)	(45.8)	(80.6)	(21.4)
Income tax expense	9.3	11.9	19.3	8.1
Unrealized (Gain) Loss on Derivative Financial Instruments | Reclassification out of Accumulated Other Comprehensive loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total before tax	(5.0)	(2.3)	(9.4)	(3.1)
Income tax expense	1.0	0.7	1.9	1.0
Net of tax	(4.0)	(1.6)	(7.5)	(2.1)
Unrealized (Gain) Loss on Derivative Financial Instruments | Reclassification out of Accumulated Other Comprehensive loss | Foreign Exchange Contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Revenue and Cost of revenue	(0.8)	0.1	(0.9)	0.3
Unrealized (Gain) Loss on Derivative Financial Instruments | Reclassification out of Accumulated Other Comprehensive loss | Interest rate swap contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest and foreign exchange	$ (4.2)	$ (2.4)	$ (8.5)	$ (3.4)