Segment Information - Reconciliation of Earnings from Operations to Earnings (Loss) Before Income Tax and Earnings from Unconsolidated Affiliates (Detail) - USD ($) $ in Millions	12 Months Ended
	Aug. 31, 2023	Aug. 31, 2022	Aug. 31, 2021
Segment Reporting [Abstract]
Earnings (loss) from operations	$ 176.4	$ 118.0	$ 41.0
Interest and foreign exchange	85.4	57.4	43.3
Net loss on extinguishment of debt			6.3
Earnings (loss) before income tax and earnings from unconsolidated affiliates	$ 91.0	$ 60.6	$ (8.6)