Carrying Amount of the Components of the Convertible Notes (Detail) (4.5% Convertible Notes due 2012, USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
4.5% Convertible Notes due 2012
Debt Outstanding [Line Items]
Principal	$ 4,915	$ 230,000
Unamortized discount	(213)	(15,951)
Net carrying amount of liability component	4,702	214,049
Carrying amount of equity component	$ 35,201	$ 36,850

Debt Outstanding [Line Items]

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- Definition

Carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Convertible Notes Payable, excluding current portion. Convertible Notes Payable is a written promise to pay a note which can be exchanged for a specified amount of another, related security, at the option of the issuer and the holder.

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- Definition

The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

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- Definition

The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

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- Definition

The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

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