Temporary Differences and Carryforwards of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Aug. 31, 2015	Aug. 31, 2014
Deferred income tax assets:
Operating loss and tax credit carryforwards	$ 19,419	$ 18,062
Compensation related liabilities	27,047	23,496
Postretirement benefits	5,462	5,082
Inventory	3,253	2,775
Book reserves and other items	11,976	12,214
Total deferred income tax assets	67,157	61,629
Valuation allowance	(8,053)	(5,608)
Net deferred income tax assets	59,104	56,021
Deferred income tax liabilities:
Depreciation and amortization	(109,447)	(124,688)
Other items	(4,539)	(5,728)
Deferred income tax liabilities	(113,986)	(130,416)
Net deferred income tax liability	$ (54,882)	$ (74,395)