Stockholders' Equity - Summary of Restricted Stock, Restricted Stock Unit and Performance Stock Unit Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015
Schedule Of Restricted Stock Restricted Stock Unit And Performance Stock Unit Activity [Line Items]
Weighted Average Grant Price, Outstanding, December 31, 2014	$ 4.79
Weighted Average Grant Price, Granted	$ 4.18
Weighted Average Grant Price, Forfeited	$ 4.82
Weighted Average Grant Price,Outstanding, March 31, 2015	$ 4.57
Weighted Average Grant Price, Expected to vest, March 31, 2015	$ 4.47
Weighted Average Remaining Contractual Term, Outstanding	1 year 9 months 18 days
Weighted Average Remaining Contractual Term, Expected to vest	2 years 1 month 6 days
Aggregate Intrinsic Value, Outstanding, March 31, 2015	$ 1,469
Aggregate Intrinsic Value, Expected to vest, March 31, 2015	$ 1,136
Restricted Stock, Restricted Stock Units and Performance Stock Units [Member]
Schedule Of Restricted Stock Restricted Stock Unit And Performance Stock Unit Activity [Line Items]
Restricted Stock, Restricted Stock Units, and Performance Stock Units Outstanding, December 31, 2014	1,048
Restricted Stock, Restricted Stock Units, and Performance Stock Units, Granted	556
Restricted Stock, Restricted Stock Units, and Performance Stock Units, Forfeited	(31)
Restricted Stock, Restricted Stock Units, and Performance Stock Units Outstanding, March 31, 2015	1,570
Restricted Stock, Restricted Stock Units, and Performance Stock Units Expected to vest, March 31, 2015	1,092
Class A Common Stock [Member]
Schedule Of Restricted Stock Restricted Stock Unit And Performance Stock Unit Activity [Line Items]
Weighted Average Grant Price Common Stock, Vested	$ 4.83
Class A Common Stock [Member] \| Restricted Stock, Restricted Stock Units and Performance Stock Units [Member]
Schedule Of Restricted Stock Restricted Stock Unit And Performance Stock Unit Activity [Line Items]
Restricted Stock, Restricted Stock Units, and Performance Stock Units Common Stock, Vested	(3)

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

+ References

No definition available.

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- Definition

The number of equity-based awards other than stock options that are expected to vest.

+ References

No definition available.

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- Definition

The weighted average fair value as of the grant date of equity-based awards other than stock options for awards that are expected to vest.

+ References

No definition available.

+ Details

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- Definition

Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMns' format, that are expected to vest.

+ References

No definition available.

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- Definition

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

+ References

No definition available.

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of grants made 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).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

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).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (e)(1)

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(2)

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