Share-based payments (Details) (USD $)	3 Months Ended	12 Months Ended							12 Months Ended			12 Months Ended						1 Months Ended		12 Months Ended
	Feb. 03, 2012	Feb. 01, 2013	Feb. 03, 2012	Jan. 28, 2011	Feb. 01, 2013 Stock options	Feb. 03, 2012 Stock options	Jan. 28, 2011 Stock options	Oct. 28, 2011 Stock options item	Feb. 03, 2012 Equity Appreciation Rights	Jan. 28, 2011 Equity Appreciation Rights	Feb. 01, 2013 Equity Appreciation Rights	Feb. 01, 2013 Restricted Stock Units	Feb. 03, 2012 Restricted Stock Units	Jan. 28, 2011 Restricted Stock Units	Feb. 01, 2013 Performance Stock Units	Feb. 03, 2012 Performance Stock Units	Jan. 28, 2011 Performance Stock Units	Apr. 06, 2012 Performance based restricted stock awards Chairman and chief executive officer	Feb. 01, 2013 2007 Stock incentive plan	Feb. 01, 2013 2007 Stock incentive plan Stock options Time Options	Feb. 03, 2012 2007 Stock incentive plan Stock options Time Options	Jan. 28, 2011 2007 Stock incentive plan Stock options Time Options	Feb. 01, 2013 2007 Stock incentive plan Stock options Performance Options	Feb. 03, 2012 2007 Stock incentive plan Stock options Performance Options	Jan. 28, 2011 2007 Stock incentive plan Stock options Performance Options	Feb. 01, 2013 2007 Stock incentive plan Stock options Time Options and Performance Options	Feb. 01, 2013 2007 Stock incentive plan Stock options Other stock option	Feb. 03, 2012 2007 Stock incentive plan Stock options Other stock option	Jan. 28, 2011 2007 Stock incentive plan Stock options Other stock option	Feb. 01, 2013 2007 Stock incentive plan Stock options Other stock option Board of directors	Feb. 01, 2013 2007 Stock incentive plan Stock options Other stock option Employee	Feb. 01, 2013 2007 Stock incentive plan Restricted Stock Units and Performance Stock Units	Feb. 03, 2012 2007 Stock incentive plan Restricted Stock Units and Performance Stock Units	Jan. 28, 2011 2007 Stock incentive plan Restricted Stock Units and Performance Stock Units
Share-based payments
Number of shares of common stock authorized for grant																			31,142,858
Shares available for future grants																			20,140,249
Vesting period																										5 years				3 years	4 years	3 years
Awards granted, purchase price (in dollars per unit)																		$ 0														$ 0	$ 0	$ 0
Grant date fair value of awards issued (in dollars per share)												$ 45.33	$ 33.16		$ 45.25			$ 45.25
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)					26.80%	38.70%	39.10%
Weighted average risk-free interest rate (as a percent)					1.50%	2.30%	2.80%
Expected term of options					6 years 3 months 18 days	6 years 9 months 18 days	7 years
Contractual term of options																										10 years
Expiration period of call option subsequent to the date of grant																										5 years
Number of companies in peer group for expected stock price volatility								4
Options Issued
Balance at the beginning of the period (in shares)																				4,258,581			3,968,237				217,137
Granted (in shares)																											1,063,303		0
Exercised (in shares)																				(2,861,681)			(2,661,902)				(8,532)
Canceled (in shares)																				(46,258)			(41,509)				(60,137)
Balance, at the end of the period (in shares)																				1,350,642	4,258,581		1,264,826	3,968,237			1,211,771	217,137
Exercisable at the end of the period (in shares)																				723,335			916,223				142,026
Average Exercise Price
Balance at the beginning of the period (in dollars per share)																				$ 10.55			$ 10.75				$ 29.05
Granted (in dollars per share)																											$ 45.46
Exercised (in dollars per share)																				$ 8.97			$ 9.12				$ 13.36
Canceled (in dollars per share)																				$ 16.10			$ 16.87				$ 45.14
Balance at the end of the period (in dollars per share)																				$ 13.69	$ 10.55		$ 13.96	$ 10.75			$ 42.77	$ 29.05
Exercisable at the end of the period (in dollars per share)																				$ 11.42			$ 12.61				$ 28.76
Remaining Contractual Term
Balance, at the end of the period																				5 years 10 months 24 days			6 years				8 years 10 months 24 days
Exercisable at the end of the period																				5 years 4 months 24 days			5 years 9 months 18 days				7 years 3 months 18 days
Intrinsic Value
Balance at the end of the period																				$ 44,017,000			$ 40,879,000				$ 4,416,000
Balance at the end of the period												13,372,000			7,529,000
Exercisable at the end of the period																				25,215,000			30,850,000				2,489,000
Weighted average grant date fair value (in dollars per share)																					$ 13.47	$ 12.61		$ 13.47	$ 12.61		$ 13.54	$ 13.14	$ 0.00
Intrinsic value of options exercised																				117,300,000	41,400,000	5,500,000	106,400,000	41,800,000	14,700,000		300,000	1,600,000	15,500,000
Units Issued
Awards outstanding at the beginning of the period (in shares or rights)											0	13,024
Granted (in shares or rights)									818,847			305,618		0	171,497	0	0	326,037
Vested (in shares or rights)									(768,561)			(4,873)
Canceled (in shares or rights)									(50,286)			(24,842)			(8,809)
Awards outstanding at the end of the period (in shares or rights)											0	288,927	13,024		162,688
Intrinsic Value
Total unrecognized compensation cost		27,700,000
Expected weighted average expense recognition period (in years)		1 year 8 months 12 days
Share-based compensation expense
Pre-tax	8,600,000	21,664,000	23,981,000	30,171,000	14,078,000	15,121,000	12,722,000		8,731,000	17,366,000		3,504,000	129,000	83,000	4,082,000
Net of tax	$ 5,300,000	$ 13,200,000	$ 14,604,000	$ 18,393,000	$ 8,578,000	$ 9,208,000	$ 7,755,000		$ 5,317,000	$ 10,587,000		$ 2,135,000	$ 79,000	$ 51,000	$ 2,487,000