Share Based Compensation (Stock Option Activity) (Details) (USD $)	9 Months Ended
	Oct. 29, 2011
Stock option activity
Number of Shares Outstanding at January 29, 2011	2,316,648
Number of Shares Outstanding, Weighted average Exercise Price	$ 39.51
Exercised, Number of Shares	(1,094,103)
Exercised, Weighted average Exercise Price	$ 30.94
Forfeited or cancelled, Number of Shares	(27,100)
Forfeited or cancelled, Weighted-Average Exercise Price	52.71
Number of Shares Outstanding at October 29, 2011	1,195,445
Number of Shares Outstanding, Weighted average Exercise Price	$ 47.06
Number of Shares Outstanding, Aggregate Intrinsic Value	$ 36,048,435
Number of Shares Outstanding, Weighted- Average Remaining Contractual Life	3.1
Stock options exercisable at October 29, 2011	1,102,395
Stock options exercisable, Weighted-Average Exercise Price	$ 46.10
Stock options exercisable, Aggregate Intrinsic Value	34,241,480
Stock options exercisable, Weighted-Average Remaining Contractual Life	2.8
Stock options expected to become exercisable in the future as of October 29, 2011	90,358
Stock options expected to become exercisable in the future as of October 29, 2011, Aggregate Intrinsic Value	$ 1,746,708
Stock options expected to become exercisable in the future as of October 29, 2011, Weighted Average Exercise Price	$ 58.54
Stock options expected to become exercisable in the future as of October 29, 2011, Weighted Average Remaining Contractual Life	6.6