Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Nov. 30, 2013		Aug. 31, 2013
Assets:
Nonqualified savings plan investments	$ 8,202		$ 7,687
Fair Value, Measurements, Recurring
Assets:
Derivative financial instruments	1,135		1,042
Nonqualified savings plan investments	8,202		7,687
Cash equivalents	1,005		1,004
Assets, Fair Value Disclosure, Total	10,342		9,733
Liabilities:
Derivative financial instruments	972		1,632
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring
Assets:
Nonqualified savings plan investments	8,202		7,687
Cash equivalents	1,005		1,004
Assets, Fair Value Disclosure, Total	9,207		8,691
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Assets:
Derivative financial instruments	1,135	[1]	1,042
Assets, Fair Value Disclosure, Total	1,135	[1]	1,042
Liabilities:
Derivative financial instruments	$ 972	[1]	$ 1,632

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