Weighted Average Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Cost (Detail)	12 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
Assumptions for benefit obligations:
Discount rate	4.90%	3.90%	5.00%
Assumptions for net periodic benefit cost:
Discount rate	3.90%	5.00%	4.60%
Expected return on plan assets	7.75%	7.90%	8.00%