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Equity Compensation (Summary of Significant Assumptions Used in Estimating Fair Value of Options Granted) (Detail)	12 Months Ended
	Dec. 25, 2011	Dec. 26, 2010	Dec. 27, 2009
Assumptions (weighted average):
Risk-free interest rate	1.50%	1.80%	1.30%
Expected dividend yield	0.00%	0.00%	0.00%
Expected volatility	0.41%	0.43%	0.41%
Expected term (in years)	3 years 8 months 12 days	3 years 8 months 12 days	3 years 8 months 12 days

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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