Segment reporting (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 29, 2016 USD ($) segment	Jul. 31, 2015 USD ($) segment	Jul. 29, 2016 USD ($) segment	Jul. 31, 2015 USD ($) segment
Net sales data for classes of similar products
Net sales	$ 5,391,891	$ 5,095,904	$ 10,657,323	$ 10,014,576
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	$ 4,116,450	$ 3,867,635	$ 8,155,647	$ 7,621,613
Seasonal
Net sales data for classes of similar products
Net sales	673,953	642,525	1,297,803	1,228,818
Home products
Net sales data for classes of similar products
Net sales	315,598	304,305	638,446	607,329
Apparel
Net sales data for classes of similar products
Net sales	$ 285,890	$ 281,439	$ 565,427	$ 556,816