Debt - Additional Information (Detail) (USD $)
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6 Months Ended | 1 Months Ended | 3 Months Ended | 6 Months Ended | 3 Months Ended | 6 Months Ended | 1 Months Ended | 1 Months Ended | |||||
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Jun. 30, 2012
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Jun. 30, 2011
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Jan. 31, 2012
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Jan. 31, 2012
Convertible Debt
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Jun. 30, 2012
Convertible Debt
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Jun. 30, 2012
Convertible Debt
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Jun. 30, 2012
Convertible Debt
Proceeds
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Jun. 30, 2012
Convertible Debt
Debt Offering
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Jun. 30, 2012
Convertible Debt
Debt Offering
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Jun. 30, 2012
Convertible Debt
American Depository Shares
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Jan. 31, 2012
3.5% exchangeable senior notes due 2032
Finance
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Jan. 09, 2012
3.5% exchangeable senior notes due 2032
Finance
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Jul. 31, 2012
3.5% exchangeable senior notes due 2032
Finance
Interest Expense
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Debt Disclosure [Line Items] | |||||||||||||
Convertible senior notes, principal amount | $ 150,000,000 | ||||||||||||
Convertible senior notes, stated interest rate | 3.50% | 3.50% | |||||||||||
Convertible senior notes, due date | 2032 | ||||||||||||
Convertible senior notes, net proceeds | 144,316,000 | 144,316,000 | 144,316,000 | ||||||||||
Convertible senior notes, exchange rate of ADS per $1,000 principal amount of notes | 113.4752 | ||||||||||||
Convertible senior notes, total ADS into which the debt is exchangeable | 17,021,280 | ||||||||||||
Convertible senior notes, payment start date | Jul. 15, 2012 | ||||||||||||
Convertible senior notes, maturity date | Jan. 15, 2032 | Jan. 15, 2032 | |||||||||||
Value of shares in excess of principal amount of Notes based on closing price | 96,100,000 | ||||||||||||
Additional interest rate on notes per annum | 0.50% | 0.50% | |||||||||||
Convertible senior notes, repurchase price at option of the issuer | 100.00% | ||||||||||||
Proceeds allocated to conversion option | 23,800,000 | ||||||||||||
Fair value of the liability component | 150,000,000 | 126,200,000 | 126,200,000 | ||||||||||
Note, estimated remaining life | 24 months | ||||||||||||
Effective interest rate | 13.50% | ||||||||||||
Unamortized debt discount | 3,800,000 | 3,800,000 | 18,800,000 | ||||||||||
Debt discount amortization period | 24 months | ||||||||||||
Convertible senior notes, carrying amount net of unamortized discount | 127,400,000 | 127,400,000 | |||||||||||
Convertible senior notes, interest expense | 4,500,000 | 8,500,000 | |||||||||||
Interest expense, contractual coupon interest accrual | 2,700,000 | 5,000,000 | |||||||||||
Interest expense, amortization of discount | 1,300,000 | 2,500,000 | 500,000 | 1,000,000 | |||||||||
Accrued interest on convertible note | 2,700,000 | 2,700,000 | |||||||||||
Interest payment on notes | $ 2,700,000 |