Fair Value Measurements (Details Textual) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Debt Instrument Value (Textual) [Abstract]
Long term debt, Book value	$ 808,050,000	$ 620,000,000
Convertible Notes Due 2017 [Member]
Debt Instrument Value (Textual) [Abstract]
Fair value of 2017 convertible notes	277,500,000
Liability attributable to Fair value of 2017 convertible	226,100,000
8.625 % Senior Notes Due 2017 [Member]
Debt Instrument Value (Textual) [Abstract]
Long term debt, Book value	375,000,000
Long term debt, Fair Value	384,400,000	386,300,000
Fair value of 2017 convertible notes		375,000,000
6.75 % Senior Notes Due 2014 [Member]
Debt Instrument Value (Textual) [Abstract]
Long term debt, Book value	200,000,000	200,000,000
Long term debt, Fair Value	$ 201,000,000	$ 199,000,000

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Liability component of convertible debt.

+ References

No definition available.

+ Details

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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. Fair value of convertible debt at the balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Convertible Security

-URI http://asc.fasb.org/extlink&oid=6509036

+ Details

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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