Asset Retirement Obligation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Asset Retirement Obligation [Abstract]
Balance at beginning of period			$ 7,357	$ 5,120
Accretion expense	$ 206	$ 77	510	232
Additions from Carbon California Company, LLC			2,921
Additions from Seneca Acquisition			639
Additions From Liberty Acquisition			30
Additions during period				5
Obligations on sale of oil & gas properties				(93)
Total			11,837	5,264
Less: ARO recognized as a current liability			(902)	(144)
Balance at end of period	$ 10,935	$ 5,120	$ 10,935	$ 5,120