Income taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 29, 2016	Jan. 30, 2015	Jan. 31, 2014	Jan. 29, 2016	Jan. 30, 2015
Current:
Federal	$ 590,120	$ 543,089	$ 530,728
Foreign	1,678	1,245	1,324
State	84,021	81,816	101,174
Total current income taxes	675,819	626,150	633,226
Deferred:
Federal	6,410	(7,697)	(16,132)
State	5,715	(2,937)	(13,880)
Total deferred income taxes	12,125	(10,634)	(30,012)
Total provision (benefit) for income taxes	687,944	615,516	603,214
Reconciliation between actual income taxes and amounts computed by applying federal statutory rate
U.S. federal statutory rate on earnings before income taxes	648,558	588,303	569,916
State income taxes, net of federal income tax benefit	59,700	49,819	56,822
Jobs credits, net of federal income taxes	(21,366)	(18,961)	(19,348)
Increase (decrease) in valuation allowances	(1,371)	1,453	(437)
Decrease in income tax reserves	(2,037)	(6,449)	(6,391)
Other, net	4,460	1,351	2,652
Total provision (benefit) for income taxes	$ 687,944	$ 615,516	$ 603,214
Reconciliation between actual income taxes rate and federal statutory rate
U.S. federal statutory rate on earnings before income taxes (as a percent)	35.00%	35.00%	35.00%
State income taxes, net of federal income tax benefit (as a percent)	3.20%	3.00%	3.50%
Jobs credits, net of federal income taxes (as a percent)	(1.20%)	(1.10%)	(1.20%)
Increase (decrease) in valuation allowances (as a percent)	(0.10%)	0.10%
Decrease in income tax reserves (as a percent)	(0.10%)	(0.40%)	(0.40%)
Other, net (as a percent)	0.30%		0.10%
Total provision (benefit) for income taxes (as a percent)	37.10%	36.60%	37.00%
Deferred tax assets:
Deferred compensation expense				$ 8,200	$ 8,842
Accrued expenses				8,139	5,146
Accrued rent				20,793	19,360
Accrued insurance				72,676	76,197
Accrued incentive compensation				19,902	14,866
Share based compensation				17,988	17,623
Interest rate hedges				3,702	4,318
Tax benefit of income tax and interest reserves related to uncertain tax positions				1,371	1,502
Deferred gain on sale- leaseback				22,637	24,385
Other				9,440	3,550
State tax credit carry forwards, net of federal tax				10,711	11,039
Total deferred tax assets, gross				195,559	186,828
Less valuation allowances				(1,474)	(2,845)
Total deferred tax assets				194,085	183,983
Deferred tax liabilities:
Property and equipment				(320,619)	(302,531)
Inventories				(72,456)	(73,188)
Trademarks				(433,548)	(433,328)
Other				(7,417)	(1,794)
Total deferred tax liabilities				(834,040)	(810,841)
Net deferred tax liabilities				(639,955)	(626,858)
State tax credit carryforwards that will expire beginning in 2021 through 2024				16,500
Increase (decrease) in valuation allowance for state tax credit carryforwards	$ (1,400)	$ 1,500	$ (400)
Reserves for uncertain tax benefits	9,343	19,583	22,237	6,964	9,343
Interest accrued related to uncertain tax benefits				900	1,000
Potential penalties accrued related to uncertain tax benefits				800	400
Reserve for uncertain tax positions for which a reduction is reasonably possible in the next twelve months				2,600
Reserve for uncertain tax positions that would impact effective tax rate if recognized				7,000
Reserves for uncertain tax benefits included in noncurrent Other liabilities				$ 8,700	$ 10,700
Income tax amounts associated with uncertain tax positions
Income tax expense (benefit)	(2,379)	(9,497)	(3,915)
Income tax related interest expense (benefit)	(23)	(1,445)	590
Income tax related penalty expense (benefit)	373	51	30
Reconciliation of the uncertain income tax positions
Beginning Balance	9,343	19,583	22,237
Increases - tax positions taken in the current year	214	198	3,484
Increases - tax positions taken in prior years	17	62	3,000
Decreases - tax positions taken in prior years	(106)	(8,636)	(608)
Statute expirations	(2,504)	(1,121)	(7,622)
Settlements		(743)	(908)
Ending Balance	$ 6,964	$ 9,343	$ 19,583