Share-based payments (Detail) (USD $)	12 Months Ended			1 Months Ended
	Jan. 30, 2015	Jan. 31, 2014	Feb. 01, 2013	Apr. 06, 2012
Share-based compensation expense
Pre-tax	$ 37,338,000	$ 20,961,000	$ 21,664,000
Net of tax	22,780,000	12,765,000	13,200,000
Total unrecognized compensation cost	55,200,000
Expected weighted average expense recognition period (in years)	1 year 4 months 24 days
Stock options
Weighted average for key assumptions used in determining the fair value
Expected dividend yield (as a percent)	0.00%	0.00%	0.00%
Expected stock price volatility (as a percent)	25.60%	26.20%	26.80%
Weighted average risk-free interest rate (as a percent)	1.90%	1.20%	1.50%
Expected term of options	6 years 3 months 18 days	6 years 3 months 18 days	6 years 3 months 18 days
Share-based compensation expense
Pre-tax	8,533,000	7,634,000	14,078,000
Net of tax	5,206,000	4,649,000	8,578,000
Performance Share Units
Share-based payments
Weighted average grant date fair value of awards issued (in dollars per share)	$ 57.91	$ 48.11	$ 45.25
Intrinsic Value
Balance at the end of the period	14,256,000
Units Issued
Awards outstanding at the beginning of the period (in shares or rights)	159,419
Granted (in shares or rights)	143,048
Vested (in shares or rights)	(68,187)
Canceled (in shares or rights)	(21,697)
Awards outstanding at the end of the period (in shares or rights)	212,583	159,419
Share-based compensation expense
Pre-tax	5,461,000	3,448,000	4,082,000
Net of tax	3,332,000	2,100,000	2,487,000
Restricted Stock Units
Share-based payments
Weighted average grant date fair value of awards issued (in dollars per share)	$ 57.87	$ 48.20	$ 45.33
Intrinsic Value
Balance at the end of the period	47,938,000
Units Issued
Awards outstanding at the beginning of the period (in shares or rights)	616,527
Granted (in shares or rights)	420,035
Vested (in shares or rights)	(230,907)
Canceled (in shares or rights)	(90,797)
Awards outstanding at the end of the period (in shares or rights)	714,858	616,527
Share-based compensation expense
Pre-tax	15,968,000	9,879,000	3,504,000
Net of tax	9,742,000	6,016,000	2,135,000
Restricted Stock | Chairman and chief executive officer
Share-based payments
Weighted average grant date fair value of awards issued (in dollars per share)				$ 45.25
Units Issued
Granted (in shares or rights)				326,037
Share-based compensation expense
Pre-tax	7,376,000
Net of tax	4,500,000
2007 Stock incentive plan
Share-based payments
Number of shares of common stock authorized for grant	31,142,858
Shares available for future grants	19,025,398
2007 Stock incentive plan | Other stock option | Board members
Share-based payments
Vesting period	3 years
2007 Stock incentive plan | Stock options | Other stock option
Options Issued
Balance at the beginning of the period (in shares)	1,840,542
Granted (in shares)	898,817
Exercise of share-based awards (in shares)	(159,205)
Canceled (in shares)	(181,030)
Balance, at the end of the period (in shares)	2,399,124	1,840,542
Exercisable at the end of the period (in shares)	633,841
Average Exercise Price
Balance at the beginning of the period (in dollars per share)	$ 45.26
Granted (in dollars per share)	$ 58.03
Exercised (in dollars per share)	$ 44.52
Canceled (in dollars per share)	$ 50.55
Balance at the end of the period (in dollars per share)	$ 49.69	$ 45.26
Exercisable at the end of the period (in dollars per share)	$ 42.43
Remaining Contractual Term
Balance, at the end of the period	8 years 1 month 6 days
Exercisable at the end of the period	7 years
Intrinsic Value
Balance at the end of the period	41,661,000
Exercisable at the end of the period	15,613,000
Weighted average grant date fair value (in dollars per share)	$ 17.26	$ 13.86	$ 13.54
Intrinsic value of options exercised	2,500,000	800,000	300,000
2007 Stock incentive plan | Stock options | Other stock option | Employee
Share-based payments
Vesting period	4 years
2007 Stock incentive plan | Stock options | Time Options
Options Issued
Balance at the beginning of the period (in shares)	464,563
Exercise of share-based awards (in shares)	(154,866)
Canceled (in shares)	(10,853)
Balance, at the end of the period (in shares)	298,844	464,563
Exercisable at the end of the period (in shares)	286,848
Average Exercise Price
Balance at the beginning of the period (in dollars per share)	$ 18.15
Exercised (in dollars per share)	$ 14.95
Canceled (in dollars per share)	$ 20.39
Balance at the end of the period (in dollars per share)	$ 19.74	$ 18.15
Exercisable at the end of the period (in dollars per share)	$ 19.30
Remaining Contractual Term
Balance, at the end of the period	4 years 8 months 12 days
Exercisable at the end of the period	4 years 7 months 6 days
Intrinsic Value
Balance at the end of the period	14,142,000
Exercisable at the end of the period	13,700,000
Intrinsic value of options exercised	6,800,000	39,400,000	117,300,000
2007 Stock incentive plan | Stock options | Performance Options
Options Issued
Balance at the beginning of the period (in shares)	376,309
Exercise of share-based awards (in shares)	(118,287)
Canceled (in shares)	(10,151)
Balance, at the end of the period (in shares)	247,871	376,309
Exercisable at the end of the period (in shares)	246,251
Average Exercise Price
Balance at the beginning of the period (in dollars per share)	$ 19.68
Exercised (in dollars per share)	$ 17.18
Canceled (in dollars per share)	$ 21.47
Balance at the end of the period (in dollars per share)	$ 20.79	$ 19.68
Exercisable at the end of the period (in dollars per share)	$ 20.73
Remaining Contractual Term
Balance, at the end of the period	4 years 10 months 24 days
Exercisable at the end of the period	4 years 10 months 24 days
Intrinsic Value
Balance at the end of the period	11,468,000
Exercisable at the end of the period	11,409,000
Intrinsic value of options exercised	$ 4,900,000	$ 39,100,000	$ 106,400,000
2007 Stock incentive plan | Stock options | Time Options and Performance Options
Share-based payments
Vesting period	5 years
Weighted average for key assumptions used in determining the fair value
Contractual term of options	10 years
2007 Stock incentive plan | Performance Share Units
Share-based payments
Vesting period	3 years
2007 Stock incentive plan | Restricted Stock Units
Share-based payments
Vesting period	3 years