Income taxes (Detail) - USD ($) $ in Thousands			12 Months Ended
	Jan. 01, 2018	Dec. 31, 2017	Feb. 02, 2018	Feb. 03, 2017	Jan. 29, 2016
Current:
Federal			$ 426,933	$ 613,009	$ 590,120
Foreign			105	135	1,678
State			79,011	88,990	84,021
Total current income taxes			506,049	702,134	675,819
Deferred:
Federal			(159,728)	11,053	6,410
Foreign			(22)
State			22,021	1,308	5,715
Total deferred income taxes			(137,729)	12,361	12,125
Total provision (benefit) for income taxes			368,320	714,495	687,944
Reconciliation between actual income taxes and amounts computed by applying federal statutory rate
U.S. federal statutory rate on earnings before income taxes			643,326	687,969	648,558
Impact of tax rate changes			(310,756)
State income taxes, net of federal income tax benefit			61,201	60,168	59,700
Jobs credits, net of federal income taxes			(26,759)	(18,952)	(21,366)
Increase (decrease) in valuation allowances, net of federal taxes			4,435	(1,474)	(1,371)
Stock-based compensation programs			(2,227)	(9,915)
Decrease in income tax reserves			(1,837)	(2,161)	(2,037)
Other, net			937	(1,140)	4,460
Total provision (benefit) for income taxes			$ 368,320	$ 714,495	$ 687,944
Reconciliation between actual income taxes rate and federal statutory rate
U.S. federal statutory rate on earnings before income taxes (as a percent)	21.00%	35.00%	33.70%	35.00%	35.00%
Impact of tax rate changes (as a percent)			(16.30%)
State income taxes, net of federal income tax benefit (as a percent)			3.20%	3.10%	3.20%
Jobs credits, net of federal income taxes (as a percent)			(1.40%)	(1.00%)	(1.20%)
Increase (decrease) in valuation allowances, net of federal taxes (as a percent)			0.20%	(0.10%)	(0.10%)
Stock-based compensation programs (as a percent)			(0.10%)	(0.50%)
Decrease in income tax reserves (as a percent)			(0.10%)	(0.10%)	(0.10%)
Other, net (as a percent)			0.10%	(0.10%)	0.30%
Effective income tax rates (as a percent)			19.30%	36.30%	37.10%
Total provisonal tax benefit			$ 335,000
Provisonal tax benefit after the rate reduction			$ 24,200
Decrease in tax rate			17.00%
Deferred tax assets:
Deferred compensation expense			$ 6,522	$ 7,626
Accrued expenses			3,324	6,958
Accrued rent			23,418	24,077
Accrued insurance			8,630	72,990
Accrued incentive compensation			6,394	15,170
Share based compensation			13,442	18,908
Interest rate hedges			1,765	3,175
Tax benefit of income tax and interest reserves related to uncertain tax positions			365	746
Deferred gain on sale- leaseback			12,847	20,872
Other			3,900	12,591
State tax net operating loss carryforwards, net of federal tax			602
State tax credit carry forwards, net of federal tax			8,350	8,765
Total deferred tax assets, gross			89,559	191,878
Less valuation allowances, net of federal taxes			(4,435)
Total deferred tax assets			85,124	191,878
Deferred tax liabilities:
Property and equipment			(255,215)	(334,430)
Inventories			(46,244)	(65,844)
Trademarks			(269,820)	(434,045)
Prepaid insurance			(22,875)
Other			(6,672)	(10,400)
Total deferred tax liabilities			(600,826)	(844,719)
Net deferred tax liabilities			(515,702)	(652,841)
State tax credit carryforwards that will expire beginning in 2022 through 2027			10,600
Apportioned state net operating loss carryforwards that will expire beginning in 2033 through 2038			17,600
Increase (decrease) in valuation allowance for state tax credit carryforwards				(1,500)
Reserve for uncertain tax positions that would impact effective tax rate if recognized			1,000
Interest accrued related to uncertain tax benefits			700	800
Potential penalties accrued related to uncertain tax benefits			800	900
Reserves for uncertain tax benefits included in noncurrent Other liabilities			2,500	4,800
Income tax amounts associated with uncertain tax positions
Income tax expense (benefit)			(2,076)	(3,795)	$ (2,379)
Income tax related interest expense (benefit)			(123)	(31)	(23)
Income tax related penalty expense (benefit)			(9)	50	373
Reconciliation of the uncertain income tax positions
Beginning Balance			3,117	6,964	9,343
Increases - tax positions taken in the current year			66	41	214
Increases - tax positions taken in prior years			27	52	17
Decreases - tax positions taken in prior years				(1,435)	(106)
Statute expirations			(2,169)	(2,453)	(2,504)
Settlements				(52)
Ending Balance			$ 1,041	$ 3,117	$ 6,964