Convertible Notes (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2011	Dec. 31, 2010
Convertible Notes
Principal amount of convertible notes	$ 172,500	$ 172,500
Unamortized discount	(42,146)	(51,000)
Total convertible notes	130,354	121,500
Total long-term convertible notes	130,354	121,500
5% Convertible Senior Notes due 2014
Convertible Notes
Principal amount of convertible notes	172,500	172,500
Unamortized discount	(42,146)	(51,000)
Total convertible notes	$ 130,354	$ 121,500
Convertible notes stated interest rate (as a percent)	5.00%	5.00%

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

Including the current and noncurrent portions, carrying value as of the balance sheet date of a written promise to pay a note, initially due after one year or beyond the operating cycle if longer, which can be exchanged for a specified amount of one or more securities (typically common stock), at the option of the issuer or the holder.

+ References

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-Name Accounting Standards Codification

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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.

+ References

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-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 21

-Paragraph 16, 20

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

Interest rate stated in the contractual debt agreement.

+ References

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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.

+ References

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