Stockholders' Equity - Summary of Stock Option Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Outstanding at December 31, 2012	1,936
Number of Shares, Granted	489
Number of Shares, Exercised	(524)
Number of Shares, Forfeited	(69)
Number of Shares, Outstanding at September 30 2013	1,832
Number of Shares, Exercisable at September 30 2013	866
Weighted Average Exercise Price Per Share, Outstanding, Beginning balance	$ 29.03
Weighted Average Exercise Price Per Share, Granted	$ 35.20
Weighted Average Exercise Price Per Share, Exercised	$ 25.46
Weighted Average Exercise Price Per Share, Forfeited	$ 32.05
Weighted Average Exercise Price Per Share, Outstanding, Ending balance	$ 31.58
Weighted Average Exercise Price Per Share, Exercisable at September 30, 2013	$ 28.73
Weighted Average Remaining Contractual Term, Outstanding at September 30, 2013	7 years 1 month 10 days
Weighted Average Remaining Contractual Term, Exercisable at September 30, 2013	5 years 1 month 21 days
Aggregate Intrinsic Value, Outstanding at September 30, 2013	$ 9,592
Aggregate Intrinsic Value, Exercisable at September 30, 2013	$ 6,995

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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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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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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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-Publisher FASB

-Name Accounting Standards Codification

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-Section 50

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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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The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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As of the balance sheet date, the weighted-average exercise price (at which grantees can acquire the shares reserved for issuance) for exercisable stock options that are fully vested or expected to vest.

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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 that were terminated.

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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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