Segment reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Aug. 02, 2013	Aug. 03, 2012	Aug. 02, 2013 segment	Aug. 03, 2012 segment
Segment reporting
Number of reportable segments			1	1
Net sales data for classes of similar products
Net sales	$ 4,394,651	$ 3,948,655	$ 8,628,384	$ 7,849,860
Consumables
Net sales data for classes of similar products
Net sales	3,301,826	2,920,821	6,496,732	5,798,103
Seasonal
Net sales data for classes of similar products
Net sales	575,891	536,738	1,105,172	1,061,231
Home products
Net sales data for classes of similar products
Net sales	265,405	255,915	531,216	514,913
Apparel
Net sales data for classes of similar products
Net sales	$ 251,529	$ 235,181	$ 495,264	$ 475,613