Share-based payments (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jan. 29, 2021	Jan. 31, 2020	Feb. 01, 2019
Share-based payments
Number of shares of common stock authorized for grant	31,142,858
Share-based compensation expense
Pre-tax	$ 68,609	$ 48,589	$ 40,879
Net of tax	50,702	$ 36,393	$ 30,618
Total unrecognized compensation cost	$ 88,900
Expected weighted average expense recognition period (in years)	1 year 10 months 24 days
Employees
Share-based payments
Vesting period	4 years
Board members
Share-based payments
Vesting period	1 year
Stock options
Weighted average for key assumptions used in determining the fair value
Expected dividend yield (as a percent)	0.90%	1.10%	1.20%
Expected stock price volatility (as a percent)	26.40%	25.30%	25.00%
Weighted average risk-free interest rate (as a percent)	0.70%	2.30%	2.70%
Expected term of options	5 years 2 months 12 days	6 years 2 months 12 days	6 years 3 months 18 days
Options Issued
Balance at the beginning of the period (in shares)	3,319,719
Granted (in shares)	673,030
Exercise of share-based awards (in shares)	(960,890)
Canceled (in shares)	(120,319)
Balance, at the end of the period (in shares)	2,911,540	3,319,719
Exercisable at the end of the period (in shares)	1,330,225
Average Exercise Price
Balance at the beginning of the period (in dollars per share)	$ 85.34
Granted (in dollars per share)	157.19
Exercised (in dollars per share)	73.19
Canceled (in dollars per share)	115.92
Balance at the end of the period (in dollars per share)	104.69	$ 85.34
Exercisable at the end of the period (in dollars per share)	$ 82.04
Remaining Contractual Term
Balance, at the end of the period	7 years
Exercisable at the end of the period	5 years 7 months 6 days
Intrinsic Value
Balance at the end of the period	$ 262,156
Exercisable at the end of the period	$ 149,743
Weighted average grant date fair value (in dollars per share)	$ 34.60	$ 30.67	$ 24.37
Intrinsic value of options exercised	$ 116,100	$ 26,600	$ 15,400
Share-based compensation expense
Pre-tax	19,933	16,128	14,556
Net of tax	$ 14,730	$ 12,080	$ 10,902
Performance Share Units
Share-based payments
Vesting period	3 years
Weighted average grant date fair value of awards issued (in dollars per share)	$ 154.53	$ 117.13	$ 92.98
Intrinsic Value
Balance at the end of the period	$ 71,432
Units Issued
Awards outstanding at the beginning of the period (in shares or rights)	217,448
Granted (in shares or rights)	240,114
Converted to common stock (in shares or rights)	(73,227)
Canceled (in shares or rights)	(17,282)
Awards outstanding at the end of the period (in shares or rights)	367,053	217,448
Share-based compensation expense
Pre-tax	$ 27,388	$ 13,343	$ 8,597
Net of tax	$ 20,240	$ 9,994	$ 6,439
Performance Share Units | Minimum
Share-based payments
Performance period	1 year
Performance Share Units | Maximum
Share-based payments
Performance period	3 years
Restricted Stock Units
Share-based payments
Weighted average grant date fair value of awards issued (in dollars per share)	$ 155.73	$ 117.20	$ 93.16
Intrinsic Value
Balance at the end of the period	$ 71,981
Units Issued
Awards outstanding at the beginning of the period (in shares or rights)	418,669
Granted (in shares or rights)	190,156
Converted to common stock (in shares or rights)	(201,934)
Canceled (in shares or rights)	(37,020)
Awards outstanding at the end of the period (in shares or rights)	369,871	418,669
Share-based compensation expense
Pre-tax	$ 21,288	$ 19,118	$ 17,726
Net of tax	$ 15,732	$ 14,319	$ 13,277
Restricted Stock Units | Employees
Share-based payments
Vesting period	3 years