Basis of presentation and accounting policies - Revenue, Advertising (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Feb. 03, 2017	Oct. 28, 2016	Jul. 29, 2016	Apr. 29, 2016	Jan. 29, 2016	Oct. 30, 2015	Jul. 31, 2015	May 01, 2015	Feb. 03, 2017	Jan. 29, 2016	Jan. 30, 2015
Revenue and gain recognition
Liability for outstanding gift cards	$ 3,400				$ 2,800				$ 3,400	$ 2,800
Breakage income related to the gift card program									500	600
Advertising costs
Advertising costs									82,700	89,300	$ 77,300
Expenses related to vendor funding for cooperative advertising offset									35,900	36,700	35,000
Accounting standards
Income tax benefit									$ (714,495)	$ (687,944)	$ (615,516)
Earnings Per Share, Diluted	$ 1.49	$ 0.84	$ 1.08	$ 1.03	$ 1.30	$ 0.86	$ 0.95	$ 0.84	$ 4.43	$ 3.95	$ 3.49
New accounting guidance effect
Accounting standards
Income tax benefit									$ 11,000
Earnings Per Share, Diluted									$ 0.04
Tax benefit of share-based awards									$ 13,700	$ 12,100