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           Summary of Significant Accounting Policies 
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        6 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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           Jul. 30, 2011 
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| Summary of Significant Accounting Policies [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Summary of significant accounting policies | 
   
    
2. Summary of significant accounting policies
    
   Information regarding the Company’s significant accounting policies is contained in Note 2,
   “Summary of significant accounting policies,” to the financial statements in the Company’s Annual
   Report on Form 10-K for the fiscal year ended January 29, 2011. Presented below in this and the
   following notes is supplemental information that should be read in conjunction with “Notes to
   Financial Statements” in the Annual Report.
    
   
Fiscal quarter
    
   The Company’s quarterly periods are the 13 weeks ending on the Saturday closest to April 30, July
   31, October 31, and January 31. The Company’s second quarters in fiscal 2011 and 2010 ended on July
   30, 2011 and July 31, 2010, respectively.
    
   
Share-based compensation
    
   The Company measures share-based compensation cost on the grant date, based on the fair value of
   the award, and recognizes the expense over the requisite service period for awards expected to
   vest. The Company estimated the grant date fair value of stock options using a Black-Scholes
   valuation model using the following assumptions for the periods indicated:
    
   
 The Company granted 124 and 745 stock options during the six months ended July 30, 2011 and July
   31, 2010, respectively. The weighted-average grant date fair value of these options was $28.62 and
   $11.38, respectively.
    
   The Company recorded stock compensation expense of $2,388 and $2,487 for the three months ended
   July 30, 2011 and July 31, 2010, respectively. The Company recorded stock compensation expense of
   $5,196 and $4,222 for the six months ended July 30, 2011 and July 31, 2010, respectively. At July
   30, 2011, there was approximately $21,290 of unrecognized compensation expense related to unvested
   options and restricted stock.
    
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