Share-Based Compensation - Aggregated Information Regarding Stock Options Granted (Detail) (USD $)	6 Months Ended	12 Months Ended
Aug. 03, 2013	Jan. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Beginning balance, Number of Options	916,612
Granted, Number of Options	56,800
Exercised, Number of Options	(74,805)
Expired or canceled, Number of Options	(21,424)
Ending balance, Number of Options	877,183	916,612
Exercisable, Number of Options	690,035
Beginning balance, Weighted Average Exercise Price	$ 8.46
Granted, Weighted Average Exercise Price	$ 10.54
Exercised, Weighted Average Exercise Price	$ 7.71
Expired or canceled, Weighted Average Exercise Price	$ 9.40
Ending balance, Weighted Average Exercise Price	$ 8.64	$ 8.46
Exercisable, Weighted Average Exercise Price	$ 8.61
Weighted Average Remaining Contractual Life (in Years)	4 years 6 months	4 years 4 months 24 days
Exercisable, Weighted Average Remaining Contractual Life (in Years)	3 years 4 months 24 days
Beginning balance, Aggregated Intrinsic Value	$ 1,624,000
Ending balance, Aggregated Intrinsic Value	2,522,901	1,624,000
Exercisable, Aggregate Intrinsic Value	$ 2,011,494

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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-Subparagraph (c)(1)(iv)(3)-(4)

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Gross number of share options (or share units) granted during the period.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

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