Stock-Based Compensation - Summary of Stock Options Activity (Detail) - $ / shares	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options, Outstanding ,Beginning Balance	571,883	509,097
Number of Options, Granted	0	123,739
Number of Options, Exercised	(3,133)	(110)
Number of Options, Forfeited	(1,627)	(12,619)
Number of Options, Expired	(3,824)
Number of Options Outstanding, Ending Balance	563,299	620,107
Number of Options, Options vested or expected to vest	417,637	464,458
Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 22.37	$ 23.84
Weighted Average Exercise Price, Granted		21.08
Weighted Average Exercise Price, Exercised	18.41	16.80
Weighted Average Exercise Price, Forfeited	19.46	26.19
Weighted Average Exercise Price, Expired	26.15
Weighted Average Exercise Price, Outstanding, Ending Balance	22.46	23.24
Weighted Average Exercise Price, Stock Options vested or expected to vest	$ 19.64	$ 24.44
Number of Options Exercisable, Outstanding, Beginning Balance	234,564	163,443
Number of Options Exercisable, Outstanding, Ending Balance	288,366

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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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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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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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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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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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As of the balance sheet date, the weighted-average exercise price for outstanding 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 of the plan that expired.

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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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