Stockholders' Equity - Summary of Nonvested Shares (Detail) (Restricted Stock Units (RSUs), USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Restricted Stock Units (RSUs)
Shares Underlying RSUs
Nonvested beginning balance (shares)	1,208,000
Granted (shares)	897,000
Vested and released (shares)	(443,312)
Forfeited (shares)	(162,000)
Nonvested ending balance (shares)	1,500,000
Average Grant Date Fair Value Price per Share
Nonvested beginning balance (usd per share)	$ 18.71
Granted (usd per share)	$ 27.77
Vested and released (usd per share)	$ 17.57
Forfeited (usd per share)	$ 23.48
Nonvested ending balance (usd per share)	$ 23.95
Weighted Remaining Vesting Period (in years)
Nonvested as of December 31, 2012	1 year 4 months 2 days
Aggregate Intrinsic Value
Nonvested as of December 31, 2012	$ 41,632

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Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeits In Period Weighted Average Grant Date Fair Value

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- Definition

Share based Compensation Arrangement by Share based Payment Award, Equity Instruments Other than Options, Nonvested, Total Intrinsic Value

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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options Vested And Released In Period Weighted Average Grant Date Fair Value

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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.

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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).

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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).

+ References

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

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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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- 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.

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

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-Name Accounting Standards Codification

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-Name Statement of Financial Accounting Standard (FAS)

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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.

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

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