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           Fair Value Disclosures (Details Textual) 
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           Sep. 30, 2014 
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           Dec. 31, 2013 
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           4.50% senior notes due two thousand eighteen [Member] 
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| Fair Value Disclosures (Textual) [Abstract] | ||
| Debt instrument, stated rate | 4.50% | 4.50% | 
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           7.15% senior notes due 2020 [Member] 
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| Fair Value Disclosures (Textual) [Abstract] | ||
| Debt instrument, stated rate | 7.15% | 7.15% | 
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           7.00% senior notes due 2022 [Member] 
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| Fair Value Disclosures (Textual) [Abstract] | ||
| Debt instrument, stated rate | 7.00% | 7.00% | 
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           1.875% convertible senior notes due 2032 [Member] 
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| Fair Value Disclosures (Textual) [Abstract] | ||
| Debt instrument, stated rate | 1.875% | 1.875% | 
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- Details 
          
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- Definition 
          Contractual interest rate for funds borrowed, under the debt agreement. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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