Segment reporting (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Feb. 03, 2017 USD ($)	Oct. 28, 2016 USD ($)	Jul. 29, 2016 USD ($)	Apr. 29, 2016 USD ($)	Jan. 29, 2016 USD ($)	Oct. 30, 2015 USD ($)	Jul. 31, 2015 USD ($)	May 01, 2015 USD ($)	Feb. 03, 2017 USD ($) segment	Jan. 29, 2016 USD ($) segment	Jan. 30, 2015 USD ($) segment
Net sales data for classes of similar products
Net sales	$ 6,009,246	$ 5,320,029	$ 5,391,891	$ 5,265,432	$ 5,286,938	$ 5,067,048	$ 5,095,904	$ 4,918,672	$ 21,986,598	$ 20,368,562	$ 18,909,588
Number of reportable segments
Number of reportable operating segments | segment									1	1	1
Consumables
Net sales data for classes of similar products
Net sales									$ 16,798,881	$ 15,457,611	$ 14,321,080
Seasonal
Net sales data for classes of similar products
Net sales									2,674,319	2,522,701	2,344,993
Home products
Net sales data for classes of similar products
Net sales									1,373,397	1,289,423	1,205,373
Apparel
Net sales data for classes of similar products
Net sales									$ 1,140,001	$ 1,098,827	$ 1,038,142