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Stockholders' Equity - Summary of Restricted Stock, Restricted Stock Unit and Performance Stock Unit Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Grant Price, Outstanding, December 31, 2014	$ 4.79
Weighted Average Grant Price, Granted	4.25
Weighted Average Grant Price, Forfeited	5.10
Weighted Average Grant Price, Outstanding, September 30, 2015	4.42
Weighted Average Grant Price, Expected to vest, September 30, 2015	$ 4.43
Weighted Average Remaining Contractual Term, Outstanding	2 years
Weighted Average Remaining Contractual Term, Expected to vest	1 year 10 months 24 days
Aggregate Intrinsic Value, Outstanding, September 30, 2015 | $	$ 1,363
Aggregate Intrinsic Value, Expected to vest, September 30, 2015 | $	$ 1,137
Restricted Stock, Restricted Stock Units and Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock, Restricted Stock Units, and Performance Stock Units Outstanding, December 31, 2014 | shares	1,048
Restricted Stock, Restricted Stock Units, and Performance Stock Units, Granted | shares	579
Restricted Stock, Restricted Stock Units, and Performance Stock Units, Forfeited | shares	(286)
Restricted Stock, Restricted Stock Units, and Performance Stock Units Outstanding, September 30, 2015 | shares	988
Restricted Stock, Restricted Stock Units, and Performance Stock Units Expected to vest, September 30, 2015 | shares	829
Class A Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Grant Price Common Stock, Vested	$ 4.67
Class A Common Stock [Member] | Restricted Stock, Restricted Stock Units and Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Stock, Restricted Stock Units, and Performance Stock Units Common Stock, Vested | shares	(353)

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Intrinsic value of equity-based awards excluding options expected to vest.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Intrinsic value of equity-based compensation awards outstanding. Excludes stock and unit options.

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