Equity Based Compensation - Summary of Option Activity for Stock Options (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares, Outstanding, Beginning Balance	600,000
Shares, Granted	0	0
Shares, Exercised	0
Shares, Expired	0
Shares, Forfeited	0
Shares, Outstanding, Ending Balance	600,000		600,000
Shares, Exercisable	600,000
Shares, Expected to vest	0
Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 8.65
Weighted Average Exercise Price, Granted	$ 0
Weighted Average Exercise Price, Exercised	$ 0
Weighted Average Exercise Price, Expired	$ 0
Weighted Average Exercise Price, Forfeited	$ 0
Weighted Average Exercise Price, Outstanding, Ending Balance	$ 8.65		$ 8.65
Weighted Average Exercise Price, Exercisable	$ 8.65
Weighted Average Exercise Price, Expected to vest	$ 0
Weighted Average Remaining Contractual Life (Yrs.), Outstanding	4 years 9 months 29 days		5 years 29 days
Weighted Average Remaining Contractual Life (Yrs.), Exercisable	4 years 9 months 29 days
Weighted Average Remaining Contractual Life (Yrs.), Expected to vest	0 years
Aggregate Intrinsic Value, Outstanding	$ 14,972
Aggregate Intrinsic Value, Exercisable	14,972
Aggregate Intrinsic Value, Expected to vest	$ 0

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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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 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 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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Amount by which the current fair value of the underlying stock exceeds the exercise price of fully vested and expected to vest options outstanding.

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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 remaining contractual term for fully vested and expected to vest options 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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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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