Employee Benefit and Stock Plans (Details 2)	12 Months Ended
Nov. 30, 2011 Year	Nov. 30, 2010 Year	Nov. 30, 2009 Year
Assumptions of Black-Scholes option-pricing model
Risk-free interest rate	0.90%	0.70%	1.90%
Expected volatility factor	65.60%	61.70%	64.30%
Expected dividend yield	3.90%	2.20%	1.60%
Expected term	5	3	4

The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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