Share-based Compensation - Schedule of Share-Based Compensation, Stock Options, Activity (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options Outstanding, Beginning Balance	47,000
Options Outstanding, granted
Options Outstanding, exercised or exchanged	(7,000)
Options Outstanding, canceled
Options Outstanding, Ending Balance	40,000
Options Outstanding, Exercisable	40,000
Options outstanding, Weighted Average Exercise Price per Share, Beginning Balance	$ 23.19
Options granted, Weighted Average Exercise Price per Share
Options exercised or exchanged, Weighted Average Exercise Price per Share	$ 10.31
Options canceled, Weighted Average Exercise Price per Share
Weighted Average Exercise Price per Share, Ending Balance	$ 25.44
Exercisable, Weighted Average Exercise Price per Share	$ 25.44
Weighted Average Remaining Contractual Life (in years), Ending balance	4 years 10 months 24 days
Weighted Average Remaining Contractual Life (in years), Exercisable	4 years 10 months 24 days
Options outstanding, Aggregate Intrinsic Value, Ending Balance	$ 309
Aggregate Intrinsic Value, Exercisable	$ 309

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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.

+ References

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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Weighted average price of options that were either forfeited or expired.

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- Definition

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

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No definition available.

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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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No definition available.

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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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