Interim Financial Statements - Additional Information (Detail) - USD ($) $ in Thousands	Feb. 28, 2021	Sep. 01, 2020	Aug. 31, 2020
Equity Class Of Treasury Stock [Line Items]
Retained earnings	$ 848,192		$ 885,460
ASU 2016-13
Equity Class Of Treasury Stock [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Sep. 01, 2020
ASU 2016-13 | Cumulative Effect Adjustment Due to Adoption
Equity Class Of Treasury Stock [Line Items]
Retained earnings		$ (500)