Annual report pursuant to Section 13 and 15(d)

Weighted-Average Assumptions (Detail)

v2.4.0.8
Weighted-Average Assumptions (Detail)
12 Months Ended
Aug. 31, 2014
Aug. 31, 2013
Aug. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]      
Dividend yield 0.11% 0.14% 0.18%
Expected volatility 38.30% 38.36% 39.97%
Risk-free rate of return 0.70% 0.84% 1.19%
Expected forfeiture rate 14.18% 15.00% 15.00%
Expected life 6 years 1 month 6 years 1 month 6 days 6 years 1 month 6 days