Segment Information - Reconciliation of Earnings (Loss) from Operations to Earnings (Loss) Before Income Tax and Earnings from Unconsolidated Affiliates (Detail) - USD ($) $ in Millions	3 Months Ended
	Nov. 30, 2021	Nov. 30, 2020
Segment Reporting [Abstract]
Earnings (loss) from operations	$ 11.8	$ (2.1)
Interest and foreign exchange	12.6	11.1
Loss before income tax and earnings (loss) from unconsolidated affiliates	$ (0.8)	$ (13.2)