Segment reporting (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 04, 2017 USD ($) segment	Jul. 29, 2016 USD ($) segment	Aug. 04, 2017 USD ($) segment	Jul. 29, 2016 USD ($) segment
Net sales data for classes of similar products
Net sales	$ 5,828,305	$ 5,391,891	$ 11,437,930	$ 10,657,323
Number of reportable segments
Number of reportable operating segments | segment	1	1	1	1
Consumables
Net sales data for classes of similar products
Net sales	$ 4,484,359	$ 4,116,450	$ 8,799,872	$ 8,155,647
Seasonal
Net sales data for classes of similar products
Net sales	717,993	673,953	1,380,631	1,297,803
Home products
Net sales data for classes of similar products
Net sales	327,648	315,598	660,798	638,446
Apparel
Net sales data for classes of similar products
Net sales	$ 298,305	$ 285,890	$ 596,629	$ 565,427