CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues
Gain on sales of assets, net	$ 4	$ (134)	$ 79	$ (69)
Total revenues	111,580	36,282	188,791	71,268
Operating expenses
Lease operating	8,730	5,370	16,026	10,286
Production and ad valorem taxes	5,795	2,119	9,887	4,098
General and administrative	5,322	3,702	11,793	7,809
Depreciation, depletion and amortization	31,273	11,076	53,354	20,886
Total operating expenses	55,694	24,822	98,993	48,185
Operating income (loss)	55,886	11,460	89,798	23,083
Other income (expense)
Interest expense	(6,150)	(1,274)	(10,751)	(1,812)
Derivatives	(52,241)	11,061	(71,036)	28,077
Other, net	(16)	82	(74)	62
Income (loss) before income taxes	(2,521)	21,329	7,937	49,410
Income tax benefit (expense)	0	0	(163)	0
Net income (loss)	(2,521)	21,329	7,774	49,410
Net income (loss) attributable to common shareholders	$ (2,521)	$ 21,329	$ 7,774	$ 49,410
Net income (loss) per share:
Basic (in dollars per share)	$ (0.17)	$ 1.42	$ 0.52	$ 3.30
Diluted (in dollars per share)	$ (0.17)	$ 1.42	$ 0.51	$ 3.27
Weighted average shares outstanding – basic (in shares)	15,058	14,992	15,050	14,992
Weighted average shares outstanding – diluted (in shares)	15,058	15,050	15,171	15,097
Oil and Gas, Exploration and Production [Member]
Revenue from External Customer [Line Items]
Crude oil	$ 101,716	$ 32,351	$ 172,974	$ 62,424
Revenues
Revenue from Contract with Customer, Including Assessed Tax	101,716	32,351	172,974	62,424
Oil and Condensate [Member]
Revenue from External Customer [Line Items]
Crude oil	5,533	2,043	8,479	4,345
Revenues
Revenue from Contract with Customer, Including Assessed Tax	5,533	2,043	8,479	4,345
Natural Gas, Production [Member]
Revenue from External Customer [Line Items]
Crude oil	3,912	1,880	6,702	4,223
Revenues
Revenue from Contract with Customer, Including Assessed Tax	3,912	1,880	6,702	4,223
Product and Service, Other [Member]
Revenue from External Customer [Line Items]
Crude oil	415	142	557	345
Revenues
Revenue from Contract with Customer, Including Assessed Tax	415	142	557	345
Natural Gas, Gathering, Transportation, Marketing and Processing [Member]
Operating expenses
Cost of Goods and Services Sold	$ 4,574	$ 2,555	$ 7,933	$ 5,106