Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2015		Aug. 31, 2014
Assets:
Nonqualified savings plan investments	$ 12,439		$ 10,223
Fair Value, Measurements, Recurring
Assets:
Derivative financial instruments	1,434		200
Nonqualified savings plan investments	12,439		10,223
Cash equivalents	5,058		35,036
Assets, Fair Value Disclosure, Total	18,931		45,459
Liabilities:
Derivative financial instruments	2,263		1,995
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring
Assets:
Nonqualified savings plan investments	12,439		10,223
Cash equivalents	5,058		35,036
Assets, Fair Value Disclosure, Total	17,497		45,259
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Assets:
Derivative financial instruments	1,434	[1]	200
Assets, Fair Value Disclosure, Total	1,434	[1]	200
Liabilities:
Derivative financial instruments	$ 2,263	[1]	$ 1,995

[1] Level 2 assets and liabilities include derivative financial instruments that are valued based on observable inputs. See Note 10 Derivative Instruments for further discussion.