Leases - Components of Operating Lease Costs (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Feb. 28, 2022	Feb. 28, 2021	Feb. 28, 2022	Feb. 28, 2021
Leases [Abstract]
Operating lease expense	$ 2.5	$ 3.6	$ 5.2	$ 7.5
Short-term lease expense	1.4	1.3	2.7	2.6
Total	$ 3.9	$ 4.9	$ 7.9	$ 10.1