Leases - Components of Operating Lease Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 28, 2021	Feb. 29, 2020	Feb. 28, 2021	Feb. 29, 2020
Leases [Abstract]
Operating lease expense	$ 3,625	$ 3,424	$ 7,493	$ 6,850
Short-term lease expense	1,280	3,217	2,586	4,730
Total	$ 4,905	$ 6,641	$ 10,079	$ 11,580