v3.8.0.1
Employee Benefit Plans - Employee Stock Purchase Plan (Details) - the ESPP - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
12 Months Ended
Feb. 03, 2018
Jan. 28, 2017
Jan. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Maximum subscription rate 15.00%    
Look-back period 24 months    
Percentage discount of purchase price per share of common shares 85.00%    
Offering period 2 years    
Purchase period 6 months    
Number of shares issued 7.0 2.3 5.9
Weighted-average price (in usd per share) $ 7.49 $ 7.33 $ 10.00
Unamortized compensation expense $ 30.1    
Number of shares available for future issuance 22.5