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Computation of Weighted Average Fair Value of Employee Stock Options using Black-Scholes Option Pricing Model Assumptions (Detail)
9 Months Ended
Jul. 31, 2012
Jul. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk-free interest rate 0.41% 0.68%
Dividend yield 4.20% 2.70%
Expected life of the option 3 years 329 days 3 years 6 months
Volatility factor 62.79% 51.68%