Fair Value Measures - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Feb. 28, 2019		Aug. 31, 2018
Assets:
Derivative financial instruments	$ 733		$ 1,557
Nonqualified savings plan investments	28,687		26,299
Cash equivalents	82,379		126,430
Assets, Fair Value Disclosure, Total	111,799		154,286
Liabilities:
Derivative financial instruments	2,813		1,566
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring
Assets:
Derivative financial instruments	0		0
Nonqualified savings plan investments	28,687		26,299
Cash equivalents	82,379		126,430
Assets, Fair Value Disclosure, Total	111,066		152,729
Liabilities:
Derivative financial instruments	0		0
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Assets:
Derivative financial instruments	733	[1]	1,557
Nonqualified savings plan investments	0	[1]	0
Cash equivalents	0	[1]	0
Assets, Fair Value Disclosure, Total	733	[1]	1,557
Liabilities:
Derivative financial instruments	2,813	[1]	1,566
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Assets:
Derivative financial instruments	0		0
Nonqualified savings plan investments	0		0
Cash equivalents	0		0
Assets, Fair Value Disclosure, Total	0		0
Liabilities:
Derivative financial instruments	$ 0		$ 0

[1] Level 2 assets and liabilities include derivative financial instruments that are valued based on observable inputs. See Note 13 - Derivative Instruments for further discussion.