Stock Option Activity (Detail) (USD $)	1 Months Ended	9 Months Ended
Apr. 24, 2012	Sep. 30, 2012
Stock options
Outstanding, beginning balance		4,504
Granted	104,035	104,035
Exercised		(1,201)
Forfeited
Outstanding, ending balance		107,338
Exercisable, ending balance		3,303
Weighted Average Exercise price\Share
Outstanding, beginning balance		$ 13.98
Granted		$ 15.65
Exercised		$ 13.98
Forfeited
Outstanding, Ending balance		$ 15.60
Exercisable, Ending balance		$ 13.98
Weighted Average Remaining Contractual Life (in years)
Outstanding, Ending balance		9 years 6 months
Exercisable, Ending balance		1 year 9 months
Aggregate Instrinsic Value
Outstanding, Aggregate Instrinsic Value		$ 96,753
Exercisable, Aggregate Instrinsic Value		$ 8,324

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Share Based Compensation Arrangement by Share Based Payment Award Options Vested and Exercisable Aggregate Intrinsic Value

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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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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 price of options that were either forfeited or expired.

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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.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including 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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Amount of difference between fair value of the underlying shares reserved for issuance and exercise prices of fully vested and expected to vest options outstanding.

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