Commitments and contingencies (Detail) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 29, 1999	Jan. 29, 2016 USD ($)	Jan. 30, 2015 USD ($)	Jan. 31, 2014 USD ($) item	Aug. 31, 2007 USD ($)
Commitments and contingencies
Number of store locations sold and leased back | item				233
Period for which asset was taken on lease under sale and leaseback transaction	23 years			15 years
Cash proceeds under sale and leaseback transaction				$ 281,600
Deferred gain under sale and leaseback transaction				67,200
Face value of promissory note purchased					$ 34,300
Future minimum payments for operating leases
2016		$ 866,444
2017		831,367
2018		783,564
2019		720,569
2020		632,998
Thereafter		3,394,301
Total minimum payments		7,229,243
Total minimum payments for capital leases		5,900
Present value of net minimum capital lease payments		4,800
Gross property and equipment recorded under capital lease		29,800	$ 29,800
Accumulated depreciation on property and equipment recorded under capital lease		12,400	10,600
Operating lease rent expenses
Minimum rentals		849,115	776,103	674,849
Contingent rentals		7,793	9,099	12,058
Operating lease rent expenses		856,908	785,202	686,907
Amortization of leasehold interests		$ 900	$ 5,800	$ 11,900
Maximum
Commitments and contingencies
Typical period of primary lease term for operating lease, build-to-suit, maximum		15 years