Share-based payments (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jan. 31, 2020	Feb. 01, 2019	Feb. 02, 2018
Share-based payments
Number of shares of common stock authorized for grant	31,142,858
Share-based compensation expense
Pre-tax	$ 48,589	$ 40,879	$ 34,323
Net of tax	36,393	$ 30,618	$ 21,373
Total unrecognized compensation cost	$ 76,100
Expected weighted average expense recognition period (in years)	2 years 1 month 6 days
Board members
Share-based payments
Vesting period	1 year
Other Stock Option | Employee
Share-based payments
Vesting period	4 years
Stock options
Weighted average for key assumptions used in determining the fair value
Expected dividend yield (as a percent)	1.10%	1.20%	1.30%
Expected stock price volatility (as a percent)	25.30%	25.00%	25.50%
Weighted average risk-free interest rate (as a percent)	2.30%	2.70%	2.10%
Expected term of options	6 years 2 months 12 days	6 years 3 months 18 days	6 years 3 months 18 days
Share-based compensation expense
Pre-tax	$ 16,128	$ 14,556	$ 11,599
Net of tax	$ 12,080	$ 10,902	$ 7,223
Stock options | Other Stock Option
Options Issued
Balance at the beginning of the period (in shares)	3,257,250
Granted (in shares)	649,139
Exercise of share-based awards (in shares)	(470,777)
Canceled (in shares)	(115,893)
Balance, at the end of the period (in shares)	3,319,719	3,257,250
Exercisable at the end of the period (in shares)	1,533,231
Average Exercise Price
Balance at the beginning of the period (in dollars per share)	$ 76.76
Granted (in dollars per share)	119.05
Exercised (in dollars per share)	71.33
Canceled (in dollars per share)	90.13
Balance at the end of the period (in dollars per share)	85.34	$ 76.76
Exercisable at the end of the period (in dollars per share)	$ 72.81
Remaining Contractual Term
Balance, at the end of the period	6 years 10 months 24 days
Exercisable at the end of the period	5 years 7 months 6 days
Intrinsic Value
Balance at the end of the period	$ 225,983
Exercisable at the end of the period	$ 123,582
Weighted average grant date fair value (in dollars per share)	$ 30.67	$ 24.37	$ 17.66
Intrinsic value of options exercised	$ 26,600	$ 15,400	$ 7,300
Performance Share Units
Share-based payments
Vesting period	3 years
Weighted average grant date fair value of awards issued (in dollars per share)	$ 117.13	$ 92.98	$ 70.68
Intrinsic Value
Balance at the end of the period	$ 33,359
Units Issued
Awards outstanding at the beginning of the period (in shares or rights)	210,989
Granted (in shares or rights)	108,584
Converted to common stock (in shares or rights)	(89,562)
Canceled (in shares or rights)	(12,563)
Awards outstanding at the end of the period (in shares or rights)	217,448	210,989
Share-based compensation expense
Pre-tax	$ 13,343	$ 8,597	$ 6,159
Net of tax	$ 9,994	$ 6,439	$ 3,835
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)	$ 117.20	$ 93.16	$ 70.90
Intrinsic Value
Balance at the end of the period	$ 64,228
Units Issued
Awards outstanding at the beginning of the period (in shares or rights)	450,039
Granted (in shares or rights)	230,577
Converted to common stock (in shares or rights)	(211,511)
Canceled (in shares or rights)	(50,436)
Awards outstanding at the end of the period (in shares or rights)	418,669	450,039
Share-based compensation expense
Pre-tax	$ 19,118	$ 17,726	$ 16,565
Net of tax	$ 14,319	$ 13,277	$ 10,315
Restricted Stock Units | Employee
Share-based payments
Vesting period	3 years