Temporary Differences and Carryforwards of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Aug. 31, 2013	Aug. 31, 2012
Deferred income tax assets:
Operating loss and tax credit carryforwards	$ 35,071	$ 16,393
Compensation related liabilities	20,812	9,909
Postretirement benefits	7,731	10,679
Inventory reserves	7,049	8,045
Book reserves and other items	11,523	12,781
Total deferred income tax assets	82,186	57,807
Valuation allowance	(22,777)	(8,153)
Net deferred income tax assets	59,409	49,654
Deferred income tax liabilities:
Depreciation and amortization	(129,498)	(156,751)
Other items	(1,985)	(2,098)
Deferred income tax liabilities	(131,483)	(158,849)
Net deferred income tax liability	$ (72,074)	$ (109,195)