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Stock Benefit Plans And Stock-Based Compensation (Summary Of Assumptions For Estimating Fair Value Of Stock-Based Awards) (Details) (USD $)
12 Months Ended
Nov. 30, 2011
years
Nov. 30, 2010
years
Nov. 30, 2009
years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted-average grant-date fair value (per share) $ 26.51    
Stock Option [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected term of stock options, minimum (years) 4.8 4.8 4.7
Expected term of stock options, maximum (years) 5.1 5.1 5.1
Risk-free interest rate, minimum 0.90% 1.30% 1.70%
Risk-free interest rate, maximum 2.10% 2.40% 2.60%
Volatility, minimum 42.00% 42.00% 48.00%
Volatility, maximum 47.00% 44.00% 56.00%
Weighted-average grant-date fair value (per share) $ 10.70 $ 4.99 $ 3.42
Employee Stock Purchase Plans [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected term of ESPP (years) 0.5 0.5 0.5
Risk-free interest rate, minimum     0.30%
Risk-free interest rate, maximum     0.40%
Risk-free interest rate 0.20% 0.20%  
Volatility, minimum 38.00% 35.00% 51.00%
Volatility, maximum 39.00% 39.00% 71.00%
Weighted-average grant-date fair value (per share) $ 6.56 $ 2.87 $ 2.12