Quarterly report pursuant to Section 13 or 15(d)

Summary of significant accounting policies – Share-based compensation (Details)

v3.10.0.1
Summary of significant accounting policies – Share-based compensation (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended 6 Months Ended
Aug. 04, 2018
Jul. 29, 2017
Aug. 04, 2018
Jul. 29, 2017
Stock options        
Weighted-average assumptions to estimate fair value        
Volatility rate (as a percent)     29.00% 31.00%
Average risk-free interest rate (as a percent)     2.40% 1.60%
Average expected life     3 years 4 months 24 days 3 years 6 months
Dividend yield (as a percent)     0.00% 0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures     163 103
Compensation expense $ 2,215 $ 2,235 $ 4,423 $ 4,377
Weighted-average grant date fair value of options granted (in dollars per share)     $ 50.10 $ 70.12
Unrecognized compensation expense 21,720   $ 21,720  
Restricted stock units        
Weighted-average assumptions to estimate fair value        
Compensation expense 3,290 2,354 5,795 $ 4,453
Unrecognized compensation expense 25,569   $ 25,569  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period     92 42
Performance-based restricted stock units        
Weighted-average assumptions to estimate fair value        
Compensation expense 1,722 $ 1,569 $ 3,179 $ 2,819
Unrecognized compensation expense $ 12,426   $ 12,426  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period     33 21