Equity-Based Compensation - Summary of Activity for ISOs (Detail) - $ / shares	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of ISOs, outstanding, Beginning Balance	210,970	215,137
Number of ISOs, granted	0	0
Number of ISOs, exercised	0	0
Number of ISOs, forfeited	(5,334)	(8,834)
Number of ISOs, expired	(22,999)	0
Number of ISOs, outstanding, Ending Balance	182,637	206,303
Number of ISOs, exercisable	148,304	96,472
Number of ISOs, expected to vest, net of forfeitures	29,183	104,836
Weighted Average Exercise Price, Beginning Balance	$ 17.43	$ 17.35
Weighted Average Exercise Price, ISOs granted
Weighted Average Exercise Price, ISOs exercised
Weighted Average Exercise Price, ISOs forfeited	15.74	17.23
Weighted Average Exercise Price, ISOs expired	17.79
Weighted Average Exercise Price, Ending Balance	17.33	17.35
Weighted Average Exercise Price, ISOs exercisable	17.70	18.00
Weighted Average Exercise Price, ISOs expected to vest, net of forfeitures	15.74	16.80
Weighted Average Grant Date Fair Value, Beginning Balance	10.67	10.62
Weighted Average Grant Date Fair Value, ISOs granted
Weighted Average Grant Date Fair Value, ISOs exercised
Weighted Average Grant Date Fair Value, ISOs forfeited	9.60	10.54
Weighted Average Grant Date Fair Value, ISOs expired	10.90
Weighted Average Grant Date Fair Value, Ending Balance	10.61	10.62
Weighted Average Grant Date Fair Value, ISOs exercisable	10.84	11.03
Weighted Average Grant Date Fair Value, ISOs expected to vest, net of forfeitures	$ 9.60	$ 10.27

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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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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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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 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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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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Weighted average grant-date fair value of non-vested options forfeited.

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Weighted average grant-date fair value of non-vested options outstanding.

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

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Weighted average grant-date fair value of exercisable options.

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Share based compensation arrangement by share based payment award options expirations in period weighted average grant date fair value.

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