Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	May 31, 2016		Aug. 31, 2015
Assets:
Nonqualified savings plan investments	$ 15,093		$ 11,815
Fair Value, Measurements, Recurring
Assets:
Derivative financial instruments	3,640		1,913
Nonqualified savings plan investments	15,093		11,815
Cash equivalents	5,076		5,071
Assets, Fair Value Disclosure, Total	23,809		18,799
Liabilities:
Derivative financial instruments	9,029		3,206
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring
Assets:
Nonqualified savings plan investments	15,093		11,815
Cash equivalents	5,076		5,071
Assets, Fair Value Disclosure, Total	20,169		16,886
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Assets:
Derivative financial instruments	3,640	[1]	1,913
Assets, Fair Value Disclosure, Total	3,640	[1]	1,913
Liabilities:
Derivative financial instruments	$ 9,029	[1]	$ 3,206

[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.