Impairment of Natural Gas and Crude Oil Properties (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Impairment of natural gas and crude oil properties [Line Items]
Document Period End Date			Sep. 30, 2019
Impairment of properties and equipment	$ 21	$ 0	$ 26,771	$ 0
Impairment of Leasehold	146	1,488	10,250	194,146
Amortization of Individually Insignificant Unproved Properties	0	0	0	84
Impairment of Oil and Gas Properties	167	1,488	37,021	194,230
Delaware Basin Unproved Property Impairment				6,300
Delaware Basin Assets [Member]
Impairment of natural gas and crude oil properties [Line Items]
Impairment of properties and equipment			26,800
Impairment of Leasehold	$ 100	$ 1,500	$ 10,300	$ 194,200