CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Revenues and other income:
Oil and gas revenue	$ 109,164	$ 212,853
Gain on sale of assets	22,751	23,769
Other income	642	439
Total revenues and other income	132,557	237,061
Costs and expenses:
Oil and gas production	32,100	16,323
Exploration expenses	98,941	12,809
General and administrative	38,667	27,413
Depletion and depreciation	37,007	46,378
Interest and other financing costs, net	10,751	9,137
Derivatives, net	(32,327)	(2,028)
Other expenses, net	628	1,277
Total costs and expenses	185,767	111,309
Income (loss) before income taxes	(53,210)	125,752
Income tax expense	25,699	50,783
Net income (loss)	$ (78,909)	$ 74,969
Net income (loss) per share:
Basic (in dollars per share)	$ (0.21)	$ 0.20
Diluted (in dollars per share)	$ (0.21)	$ 0.19
Weighted average number of shares used to compute net income (loss) per share:
Basic (in shares)	380,355	377,830
Diluted (in shares)	380,355	381,472