Annual report pursuant to Section 13 and 15(d)

Goodwill And Other Intangible Assets And Liabilities (Estimated Useful Lives Of Intangible Assets Subject To Periodic Amortization On A Straight-Line Basis) (Details)

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Goodwill And Other Intangible Assets And Liabilities (Estimated Useful Lives Of Intangible Assets Subject To Periodic Amortization On A Straight-Line Basis) (Details)
12 Months Ended
Dec. 31, 2011
Permits [Member]
 
Finite-Lived Intangible Assets [Line Items]  
Intangible Assets Estimated Useful Life Minimum 15
Intangible Assets Estimated Useful Life Maximum 28
Utility Contracts [Member]
 
Finite-Lived Intangible Assets [Line Items]  
Useful Life (years) 5
Lease Agreements [Member]
 
Finite-Lived Intangible Assets [Line Items]  
Intangible Assets Estimated Useful Life Minimum 1.5
Intangible Assets Estimated Useful Life Maximum 4.5