Intangibles and Other Assets, Net - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Feb. 28, 2019	Feb. 28, 2018	Feb. 28, 2019	Feb. 28, 2018
Schedule of Intangible Assets Disclosure [Line Items]
Amortization expense	$ 1.4	$ 1.4	$ 3.4	$ 2.7
Future amortization expense, 2019	5.8		5.8
Future amortization expense, 2020	5.1		5.1
Future amortization expense, 2021	5.1		5.1
Future amortization expense, 2022	3.7		3.7
Future amortization expense, 2023	$ 3.5		$ 3.5