Basis of presentation (Details) $ in Millions	3 Months Ended		12 Months Ended
	May 04, 2018 USD ($)	May 05, 2017 USD ($)	Feb. 01, 2019 period	Feb. 02, 2018 period
Basis of presentation
Fiscal year, number of weeks | period			52	52
Merchandise inventories
LIFO provision (benefit) | $	$ 2.1	$ 0.8