Stock-based Compensation - Summary of Status and Activity of Stock Options (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2018 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options, Outstanding at December 31, 2017 \| shares	942,537
Options, Granted \| shares	144,825
Options, Exercised \| shares	(79,055)
Options, Forfeited \| shares	(26,367)
Options, Outstanding at December 31, 2018 \| shares	981,940
Options, Exercisable at December 31, 2018 \| shares	642,092
Weighted Average Exercise Price per Option, Outstanding at December 31, 2017 \| $ / shares	$ 27.59
Weighted Average Exercise Price per Option, Granted \| $ / shares	41.50
Weighted Average Exercise Price per Option, Exercised \| $ / shares	26.37
Weighted Average Exercise Price per Option, Forfeited \| $ / shares	31.67
Weighted Average Exercise Price per Option, Outstanding at December 31, 2018 \| $ / shares	29.63
Weighted Average Exercise Price per Option, Exercisable at December 31, 2018 \| $ / shares	$ 29.03
Weighted Average Remaining Contractual Term, Outstanding at December 31, 2018	5 years 9 months 18 days
Weighted Average Remaining Contractual Term, Exercisable at December 31, 2018	4 years 6 months
Aggregate Intrinsic Value, Outstanding at December 31, 2018 \| $	$ 0
Aggregate Intrinsic Value, Exercisable at December 31, 2018 \| $	$ 0

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

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