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           Supplemental Cash Flow Information and Disclosures of Non-Cash Transactions (Details) (USD $) 
        In Thousands, unless otherwise specified  | 
        9 Months Ended | |
|---|---|---|
| 
           Sep. 30, 2012 
         | 
        
           Sep. 30, 2011 
         | 
      |
| Supplemental Cash Flow Information [Abstract] | ||
| Cash paid during the year for interest, net of amounts capitalized | $ 117,190 | $ 108,455 | 
| Construction-in-process funded with accrued liabilities | $ 52,830 | $ 0 | 
| X | ||||||||||
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- Definition 
          Future cash outflow to pay for construction in progress expenditures that have occurred. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          The amount of cash paid for interest during the period net of cash paid for interest that is capitalized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Details 
          
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