Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Property and Equipment
Proved oil and gas properties	$ 1,146,106		$ 1,146,106		$ 925,865
Unproved oil and gas properties	43,066		43,066		56,715
Furniture, fixtures, and other equipment	4,499		4,499		3,520
Less - Accumulated depreciation, depletion, and amortization	(355,574)		(355,574)		(284,804)
Net Furniture, Fixtures and other equipment	838,097		838,097		701,296
Disaggregation of Revenue [Line Items]
Oil and gas sales	72,014	$ 65,034	218,781	$ 169,134
Accounts Payable and Accrued Liabilities
Trade accounts payable	22,950		22,950		32,683
Accrued operating expenses	3,664		3,664		3,549
Accrued compensation costs	4,079		4,079		4,785
Asset retirement obligation - current portion	307		307		302
Accrued non-income based taxes	4,502		4,502		3,583
Accrued corporate and legal fees	314		314		534
Other payables	3,135		3,135		3,485
Total accounts payable and accrued liabilities	38,951		38,951		$ 48,921
Oil sales [Member]
Disaggregation of Revenue [Line Items]
Oil and gas sales	28,894	11,124	68,441	32,202
Natural gas sales [Member]
Disaggregation of Revenue [Line Items]
Oil and gas sales	37,051	43,697	131,925	115,833
NGL sales [Member]
Disaggregation of Revenue [Line Items]
Oil and gas sales	6,080	10,213	18,400	21,113
Other sales [Member]
Disaggregation of Revenue [Line Items]
Oil and gas sales	$ (11)	$ 0	$ 16	$ (14)