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Discontinued Operations - Schedule of Impairment Charge (Details) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2015
Dec. 31, 2017
Dec. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]      
Net book value of assets conveyed $ 22,824    
Asset retirement obligations assumed by Purchaser (204)
Impairment charge recognized in 2015 $ 22,620