Segment reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Aug. 03, 2012	Jul. 29, 2011	Aug. 03, 2012 ReportableSegments	Jul. 29, 2011 ReportableSegments
Segment reporting
Number of reportable segments			1	1
Net sales data for classes of similar products
Net sales	$ 3,948,655	$ 3,575,194	$ 7,849,860	$ 7,026,891
Consumables
Net sales data for classes of similar products
Net sales	2,920,821	2,611,070	5,798,103	5,140,140
Seasonal
Net sales data for classes of similar products
Net sales	536,738	502,569	1,061,231	959,626
Home products
Net sales data for classes of similar products
Net sales	255,915	235,803	514,913	470,011
Apparel
Net sales data for classes of similar products
Net sales	$ 235,181	$ 225,752	$ 475,613	$ 457,114