Consolidated statements of operations - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Revenues:
Oil, NGL and natural gas sales		$ 431,734		$ 737,203	$ 664,844
Midstream service revenues		6,548		2,245	413
Sales of purchased oil		168,358		54,437	0
Total revenues		606,640		793,885	665,257
Costs and expenses:
Lease operating expenses		108,341		96,503	79,136
Production and ad valorem taxes		32,892		50,312	42,396
Midstream service expenses		5,846		5,429	3,368
Minimum volume commitments		5,235		2,552	891
Costs of purchased oil		174,338		53,967	0
Drilling rig fees		0		527	0
General and administrative	[1]	90,425		106,044	89,696
Restructuring expenses		6,042		0	0
Accretion of asset retirement obligations		2,423		1,787	1,475
Depletion, depreciation and amortization	[2]	277,724		246,474	233,944
Impairment expense		2,374,888		3,904	0
Total costs and expenses		3,078,154		567,499	450,906
Operating income (loss)		(2,471,514)		226,386	214,351
Gain (loss) on derivatives:
Commodity derivatives, net		214,291		327,920	79,902
Interest rate derivatives, net		0		0	(24)
Income (loss) from equity method investee		6,799		(192)	29
Interest expense	[3]	(103,219)		(121,173)	(100,327)
Interest and other income		426		294	163
Loss on early redemption of debt		(31,537)	[4]	0	0
Write-off of debt issuance costs		0		(124)	(1,502)
Loss on disposal of assets, net		(2,127)		(3,252)	(1,508)
Non-operating income (expense), net		84,633		203,473	(23,267)
Income (loss) from continuing operations before income taxes		(2,386,881)		429,859	191,084
Income tax benefit (expense):
Deferred		176,945		(164,286)	(74,507)
Total income tax benefit (expense)	[5]	176,945		(164,286)	(74,507)
Income (loss) from continuing operations		(2,209,936)		265,573	116,577
Income from discontinued operations, net of tax		0		0	1,423
Net income (loss)		$ (2,209,936)		$ 265,573	$ 118,000
Basic:
Income (loss) from continuing operations (in dollars per share)		$ (11.10)		$ 1.88	$ 0.88
Income from discontinued operations, net of tax (in dollars per share)		0.00		0.00	0.01
Net income (loss) per share (in dollars per share)		(11.10)		1.88	0.89
Diluted:
Income (loss) from continuing operations (in dollars per share)		(11.10)		1.85	0.87
Income from discontinued operations, net of tax (in dollars per share)		0.00		0.00	0.01
Net income (loss) per share (in dollars per share)		$ (11.10)		$ 1.85	$ 0.88
Weighted average common shares outstanding:
Basic (in shares)	[6]	199,158		141,312	132,490
Diluted (in shares)		199,158		143,554	134,378

[1] General and administrative costs were allocated based on the number of employees in the respective segment for the years ended December 31, 2015, 2014 and 2013. Certain components of general and administrative costs were not allocated and were based on actual costs for each segment, which primarily consisted of payroll, deferred compensation and vehicle costs for the years ended December 31, 2015 and 2014 and payroll and deferred compensation for the year ended December 31, 2013. Costs associated with land and geology were not allocated to the midstream and marketing segment for the years ended December 31, 2015, 2014 and 2013.

[2] Depletion, depreciation and amortization were based on actual costs for each segment with the exception of the allocation of depreciation of other fixed assets, which was based on the number of employees in the respective segment for the years ended December 31, 2015, 2014 and 2013.

[3] Interest expense was allocated to the exploration and production segment based on gross property and equipment for the years ended December 31, 2015, 2014 and 2013 and allocated to the midstream and marketing segment based on gross property and equipment and life-to-date contributions to the Company's equity method investee for the years ended December 31, 2015, 2014 and 2013.

[4] Loss on early redemption of debt was allocated to the exploration and production segment based on gross property and equipment for the year ended December 31, 2015 and allocated to the midstream and marketing segment based on gross property and equipment and life-to-date contributions to the Company's equity method investee for the year ended December 31, 2015.

[5] Income tax benefit or expense for the midstream and marketing segment was calculated by multiplying income (loss) from continuing operations before income taxes by 36%

[6] For the year ended December 31, 2015, weighted-average common shares outstanding used in the computation of basic and diluted net loss per share attributable to stockholders was computed taking into account the March 2015 Equity Offering. For the year ended December 31, 2013, weighted-average common shares outstanding used in the computation of basic and diluted net income per share attributable to stockholders was computed taking into account the August 2013 Equity Offering.