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Share-Based Compensation Expense - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
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]        
Share-based compensation expense $ 3.0 $ 4.3 $ 7.1 $ 7.0