Stock Option Activity (Detail) (Stock Options [Member], USD $)	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012
Stock Options [Member]
Share Based Compensation [Line Items]
Number of Options Outstanding, Beginning Balance	243,886
Stock Options Exercised, Number of Shares	(37,558)
Stock Options Canceled, Forfeited or Expired, Number of Shares	(11,835)
Number of Options Outstanding, Ending Balance	194,493	243,886
Stock Options Exerciseable, Number of Shares	194,493
Options Outstanding, Beginning Balance, Weighted Average Exercise Price	$ 20.08
Stock Options Exercised, Weighted Average Exercise Price	$ 6.95
Stock Options Canceled, Forfeited or Expired, Weighted Average Exercise Price	$ 20.02
Options Outstanding, Ending Balance, Weighted Average Exercise Price	$ 22.62	$ 20.08
Stock Options Exerciseable, Weighted Average Exercise Price	$ 22.62
Options Outstanding, Weighted Average Contractual Life	9 months 29 days	1 year 7 months 28 days
Stock Options Exerciseable, Weighted Average Contractual Life	9 months 29 days

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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 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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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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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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