Consolidated Statements of Operations - USD ($) shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues:
Crude oil, natural gas and NGLs sales	$ 213,602,000	$ 110,841,000	$ 403,294,000	$ 186,208,000
Commodity price risk management gain, net of settlements	57,932,000	(92,801,000)	138,636,000	(81,745,000)
Other income	3,624,000	2,057,000	6,935,000	6,465,000
Total revenues	275,158,000	20,097,000	548,865,000	110,928,000
Costs, expenses and other:
Lease operating expenses	20,028,000	13,675,000	39,817,000	29,005,000
Production taxes	15,042,000	6,043,000	27,441,000	10,114,000
Transportation, gathering and processing expenses	6,488,000	4,465,000	12,390,000	8,506,000
General and administrative expense	29,531,000	23,579,000	55,846,000	46,358,000
Exploration, geologic, and geophysical expense	1,033,000	237,000	1,987,000	447,000
Depreciation, depletion and amortization	126,013,000	107,014,000	235,329,000	204,402,000
Results of Operations, Impairment of Oil and Gas Properties	27,566,000	4,170,000	29,759,000	5,171,000
Accretion of asset retirement obligation	1,666,000	1,811,000	3,434,000	3,623,000
(Gain) Loss on Disposition of Oil and Gas Property	(532,000)	260,000	(692,000)	176,000
Provision for uncollectible notes receivable	(40,203,000)	0	(40,203,000)	44,738,000
Other expenses	3,890,000	2,125,000	7,418,000	4,703,000
Total cost, expenses and other	190,522,000	163,379,000	372,526,000	357,243,000
Income (loss) from operations	84,636,000	(143,282,000)	176,339,000	(246,315,000)
Interest expense	(19,617,000)	(10,672,000)	(39,084,000)	(22,566,000)
Interest income	768,000	177,000	1,008,000	1,735,000
Income (loss) before income taxes	65,787,000	(153,777,000)	138,263,000	(267,146,000)
Income tax (expense) benefit	(24,537,000)	58,327,000	(50,867,000)	100,166,000
Net income (loss)	$ 41,250,000	$ (95,450,000)	$ 87,396,000	$ (166,980,000)
Earnings per share:
Basic	$ 0.63	$ (2.04)	$ 1.33	$ (3.78)
Diluted	$ 0.62	$ (2.04)	$ 1.32	$ (3.78)
Weighted-average common shares outstanding
Basic	65,859	46,742	65,804	44,175
Diluted	66,019	46,742	66,066	44,175