Intangibles and Other Assets, Net - Identifiable Intangible and Other Assets (Detail) - USD ($) $ in Millions	Aug. 31, 2023	Aug. 31, 2022
Intangibles and Other Assets by Major Class [Line Items]
Finite-Lived Intangible Assets, Net, Total	$ 39.1	$ 47.3
Intangible assets not subject to amortization	2.3	2.4
Prepaid and other assets	56.4	32.4
Operating lease right of use asset	$ 70.6	$ 54.2
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Total Intangible and other assets, net	Total Intangible and other assets, net
Nonqualified savings plan investments	$ 47.7	$ 40.3
Debt issuance costs, net	6.3	8.7
Assets held for sale	0.3	3.8
Deferred tax assets	33.1
Total Intangible and other assets, net	255.8	189.1
Customer and supplier relationships
Intangibles and Other Assets by Major Class [Line Items]
Finite lived intangible assets gross	87.5	87.5
Accumulated amortization	(69.1)	(66.1)
Other Intangible Assets
Intangibles and Other Assets by Major Class [Line Items]
Finite lived intangible assets gross	43.0	42.4
Accumulated amortization	$ (22.3)	$ (16.5)