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Weighted Average Assumptions used to Calculate Fair Value of Each Time Based Equity Award Using Black Scholes Option Pricing Model (Detail) (Time Based Option Award, USD $)	3 Months Ended		6 Months Ended
	Jul. 28, 2012	Jul. 30, 2011	Jul. 28, 2012	Jul. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value	$ 3.73	$ 6.24	$ 5.59	$ 6.09
Expected volatility	46.00%	46.00%	44.00%	43.00%
Expected term	4 years 9 months 18 days	4 years 9 months 18 days	4 years 9 months 18 days	4 years 9 months 18 days
Risk-free interest rate	0.70%	1.70%	0.90%	2.10%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	2.00%		0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield			2.00%

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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