Weighted-Average Actuarial Assumptions used to Determine Net Periodic Benefit Cost (Detail)	12 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
Compensation And Retirement Disclosure [Abstract]
Expected long-term return on plan assets	5.10%	4.20%	4.20%
Rate of compensation increase	3.90%	3.30%	4.20%
Discount rate	4.10%	3.20%	4.90%