Fair Value Measures - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands		Feb. 28, 2021	Aug. 31, 2020
Assets:
Nonqualified savings plan investments		$ 44,150	$ 35,744
Fair Value, Measurements, Recurring
Assets:
Derivative financial instruments		6	582
Nonqualified savings plan investments		44,150	35,744
Cash equivalents		203,760	203,509
Assets, Fair Value Disclosure, Total		247,916	239,835
Liabilities:
Derivative financial instruments		12,903	15,907
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring
Assets:
Nonqualified savings plan investments		44,150	35,744
Cash equivalents		203,760	203,509
Assets, Fair Value Disclosure, Total		247,910	239,253
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Assets:
Derivative financial instruments	[1]	6	582
Assets, Fair Value Disclosure, Total	[1]	6	582
Liabilities:
Derivative financial instruments	[1]	$ 12,903	$ 15,907

[1] Level 2 assets and liabilities include derivative financial instruments that are valued based on observable inputs. See Note 11 - Derivative Instruments for further discussion.