Stock-Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended	12 Months Ended
	Jul. 28, 2012	Jan. 28, 2011
Stock option activity
Common Stock Options, Beginning Balance	1,600
Common Stock Options, Granted	121
Common stock options, Exercised	(48)
Common stock options, Expired or forfeited	(13)
Common Stock Options, Ending Balance	1,660
Common Stock Options, Vested	1,006
Weighted- Average Exercise Price, Beginning Balance	$ 18.41
Weighted- Average Exercise Price, Granted	$ 27.40
Weighted - Average Exercise Price, Exercised	$ 6.16
Weighted- Average Exercise Price, Expired or forfeited	$ 19.92
Weighted- Average Exercise Price, Ending Balance	$ 19.40
Weighted- Average Exercise Price, Vested	$ 14.18
Weighted- Average Remaining Contractual Term, Beginning Balance	7 years 3 months 4 days	7 years 3 months 26 days
Weighted- Average Remaining Contractual Term, Ending Balance	7 years 3 months 4 days	7 years 3 months 26 days
Weighted- Average Remaining Contractual Term, Vested	6 years 1 month 28 days
Aggregate Intrinsic Value, Beginning Balance	$ 15,680
Aggregate Intrinsic Value, Ending Balance	14,610
Aggregate Intrinsic Value, Vested	$ 13,916