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Asset Retirement Obligations - Summary of Asset Retirement Obligation (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Asset Retirement Obligation Disclosure [Abstract]    
Balance, beginning of period $ 4,468 $ 4,196
Liabilities settled (54) (178)
Accretion expense 480 450
Balance, end of period 4,894 4,468
Less: Included in liabilities held for sale (105) (105)
Less: Current portion (121) (121)
Non-current Portion $ 4,668 $ 4,242