Employee Benefit Plans - Summary of Stock Options Outstanding (Detail) (Stock Options Outstanding [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Stock Options Outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Vested and expected to vest	8,759
Weighted Average Exercise Price, Vested and expected to vest	$ 6.84
Weighted Average Remaining Contractual Term (Years), Vested and expected to vest	3 years 2 months 12 days
Aggregate Intrinsic Value, Vested and expected to vest	$ 2,473
Number of Shares, Exercisable	6,823
Weighted Average Exercise Price, Exercisable	$ 7.03
Weighted Average Remaining Contractual Term (Years), Exercisable	2 years 4 months 24 days
Aggregate Intrinsic Value, Exercisable	$ 1,879

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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.

+ References

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-Name Accounting Standards Codification

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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.

+ References

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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.

+ References

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

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Weighted average remaining contractual term for fully vested and expected to vest options that are 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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Amount of difference between fair value of the underlying shares reserved for issuance and exercise prices of fully vested and expected to vest options outstanding.

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

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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.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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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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