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Basis of Presentation (Details) - USD ($)
$ in Thousands
Sep. 30, 2019
Dec. 31, 2018
Change in Accounting Estimate [Line Items]    
Asset retirement obligation, current $ 13,968 $ 25,393
Asset retirement obligations, noncurrent 45,901 $ 34,671
Service Life    
Change in Accounting Estimate [Line Items]    
Asset retirement obligation, current 9,700  
Asset retirement obligations, noncurrent $ (9,700)