Stock-Based Compensation (Summary Of Fair Value Assumptions) (Details) (USD $)	3 Months Ended	6 Months Ended
Jul. 31, 2011	Aug. 01, 2010 years	Jul. 31, 2011	Aug. 01, 2010 years
Stock-Based Compensation
Expected lives, in years		5.0		5.0
Range of expected lives, lower limit	4.4		4.4
Range of expected lives, upper limit	4.7		4.7
Estimated volatility	41.00%	40.00%		40.00%
Range of estimated volitility, lower limit			40.00%
Range of estimated volitility, upper limit			41.00%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Range of risk-free interest rate, lower limit	1.60%	1.80%	1.60%	1.80%
Range of risk-free interest rate, upper limit	1.65%	2.10%	1.80%	2.30%
Weighted average fair value on grant date	$ 10.09	$ 6.46	$ 8.54	$ 6.39

Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Term Lower Limit.

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Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Term Upper Limit

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Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate Lower Limit

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Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate Upper Limit

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Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Lower Limit

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Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Upper Limit

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph e(2)(c)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Name Accounting Standards Codification
-Topic 718
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-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-Subparagraph (SAB TOPIC 14.D.2)
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-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14
-Section D
-Subsection 2

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph e(2)(b)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph c(1)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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