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Stock-Based Compensation and Employee Benefit Plans - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified |
1 Months Ended | 9 Months Ended | 9 Months Ended | 9 Months Ended | 9 Months Ended | 9 Months Ended | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Aug. 21, 2012
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Sep. 30, 2012
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Dec. 31, 2011
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Sep. 30, 2012
Class A Common Stock [Member]
Vote
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Aug. 31, 2012
Class A Common Stock [Member]
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Dec. 31, 2011
Class A Common Stock [Member]
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Sep. 30, 2012
Class B Common Stock [Member]
Vote
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Aug. 31, 2012
Class B Common Stock [Member]
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Dec. 31, 2011
Class B Common Stock [Member]
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Dec. 31, 2011
Equity Incentive Plan [Member]
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Sep. 30, 2012
Employee Stock Purchase Plan [Member]
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Dec. 31, 2011
Employee Stock Purchase Plan [Member]
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Sep. 30, 2012
Restricted Stock Units [Member]
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Sep. 30, 2011
Restricted Stock Units [Member]
|
Sep. 30, 2012
Restricted Stock Awards [Member]
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Sep. 30, 2011
Restricted Stock Awards [Member]
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||||||||||||
| Weighted-average grant date fair value per share | $ 5.87 | $ 8.53 | $ 5.87 | $ 0.00 | ||||||||||||
| Eligible options to purchase shares | 1,327,000 | 591,000 | ||||||||||||||
| Restricted stock units Issued | 959,000 | |||||||||||||||
| Share based compensation expense Exchange Offer | $ 7.3 | |||||||||||||||
| Incremental value attributed to the modified options | 1.8 | |||||||||||||||
| Number of shares Repurchase | 1,152,000 | 500,000 | ||||||||||||||
| Aggregate repurchase price | $ 9.2 | |||||||||||||||
| Percentage of fair value market of common stock | 100.00% | |||||||||||||||
| Vesting period for new restricted stock units | 4 years | |||||||||||||||
| Term of option granted, minimum | 7 years | |||||||||||||||
| Term of option granted, maximum | 10 years | |||||||||||||||
| Shares authorized for issuance | 1,329,000 | 415,000 | ||||||||||||||
| Contribution of earnings by employees | 15.00% | |||||||||||||||
| Percentage of purchase of common stock | 85.00% | |||||||||||||||
| Percentage of common stock on the date of purchase | 85.00% | |||||||||||||||
| Common stock, shares authorized | 550,000,000 | 550,000,000 | 500,000,000 | 500,000,000 | 500,000,000 | 500,000,000 | ||||||||||
| Voting rights per share | 1 | 10 | ||||||||||||||
| Number of convertible common stock | 1 | |||||||||||||||