Income taxes - (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 29, 2021	Jan. 31, 2020	Feb. 01, 2019	Feb. 02, 2018
Current:
Federal	$ 614,207	$ 368,451	$ 320,361
Foreign	127	102	159
State	100,002	65,215	53,091
Total current income taxes	714,336	433,768	373,611
Deferred:
Federal	32,433	45,966	48,262
Foreign	(104)	(15)	(38)
State	2,665	9,456	4,109
Total deferred income taxes	34,994	55,407	52,333
Total provision (benefit) for income taxes	749,330	489,175	425,944
Reconciliation between actual income taxes and amounts computed by applying federal statutory rate
U.S. federal statutory rate on earnings before income taxes	714,920	462,364	423,237
State income taxes, net of federal income tax benefit	81,117	60,936	44,584
Jobs credits, net of federal income taxes	(27,479)	(27,768)	(27,506)
Other, net	(19,228)	(6,357)	(14,371)
Total provision (benefit) for income taxes	$ 749,330	$ 489,175	$ 425,944
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%	21.00%	21.00%
State income taxes, net of federal income tax benefit (as a percent)	2.40%	2.80%	2.20%
Jobs credits, net of federal income taxes (as a percent)	(0.80%)	(1.30%)	(1.40%)
Other, net (as a percent)	(0.60%)	(0.30%)	(0.70%)
Total provision (benefit) for income taxes (as a percent)	22.00%	22.20%	21.10%
Increase in tax rate		1.10%
Decrease in tax rate	0.20%
Deferred tax assets:
Deferred compensation expense	$ 9,161	$ 7,556
Accrued expenses	52,195	16,788
Accrued rent	650	401
Lease liabilities	2,459,976	2,167,780
Accrued insurance	6,550	5,895
Accrued incentive compensation	46,083	16,721
Share based compensation	19,495	16,321
Interest rate hedges	730	1,076
Tax benefit of income tax and interest reserves related to uncertain tax positions	189	164
Other	6,823	3,702
State tax net operating loss carryforwards, net of federal tax	804	555
State tax credit carry forwards, net of federal tax	6,619	7,534
Total deferred tax assets, gross	2,609,275	2,244,493
Less valuation allowances, net of federal income taxes	(4,077)	(4,077)
Total deferred tax assets	2,605,198	2,240,416
Deferred tax liabilities:
Property and equipment	(481,279)	(389,080)
Lease assets	(2,433,195)	(2,143,996)
Inventories	(74,985)	(59,075)
Trademarks	(312,258)	(310,862)
Prepaid insurance	(13,532)	(11,933)
Other	(498)	(697)
Total deferred tax liabilities	(3,315,747)	(2,915,643)
Net deferred tax liabilities	(710,549)	(675,227)
State tax credit carryforwards that will expire beginning in 2022 through 2028	6,600
Apportioned state net operating loss carryforwards that will expire beginning in 2032 through 2039	20,900
Increase (decrease) in valuation allowance for state tax credit carryforwards		(400)		$ 4,400
Reserve for uncertain tax positions that would impact effective tax rate if recognized	7,500	5,100
Interest accrued related to uncertain tax benefits	500	400
Potential penalties accrued related to uncertain tax benefits	0	0
Reserves for uncertain tax benefits included in noncurrent Other liabilities	8,000	5,500
Reserve for uncertain tax positions for which a reduction is reasonably possible in the next twelve months	3,400
Income tax amounts associated with uncertain tax positions
Income tax expense (benefit)	2,411	130	$ 3,919
Income tax related interest expense (benefit)	104	(406)	133
Income tax related penalty expense (benefit)		(882)	33
Reconciliation of the uncertain income tax positions
Beginning Balance	5,090	4,960	1,041
Increases - tax positions taken in the current year			95
Increases - tax positions taken in prior years	3,857	1,239	3,914
Decreases - tax positions taken in prior years	(1,445)	(1,109)
Settlements			(90)
Ending Balance	$ 7,502	$ 5,090	$ 4,960	$ 1,041