Fair Value Measurements (Details)
$ in Thousands
3 Months Ended 6 Months Ended
Aug. 01, 2015
USD ($)
Aug. 02, 2014
USD ($)
stores
Aug. 01, 2015
USD ($)
Aug. 02, 2014
USD ($)
stores
Jan. 31, 2015
USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Impairment charge $ 0 $ 2,000 $ 0 $ 2,800  
Number of stores impaired during the period | stores   2   6  
Level 1 [Member] | Recurring [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
U.S. treasury securities money market funds 2,002   2,002   $ 166,602
Level 2 [Member] | Recurring [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
U.S. treasury securities money market funds 0   0   0
Level 3 [Member] | Recurring [Member]          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
U.S. treasury securities money market funds $ 0   $ 0   $ 0