CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) (in thousands, except per share amounts) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Operating revenues:
Oil, gas, and NGL production revenue	$ 623,109		$ 469,575
Other operating revenues	9,611		14,605
Total operating revenues	632,720		484,180
Operating expenses:
Oil, gas, and NGL production expense	163,709		125,633
Depletion, depreciation, amortization, and asset retirement obligation liability accretion	177,215		198,709
Exploration	21,335		15,398
Impairment of properties	2,801		21,521
General and administrative	35,051		32,280
Change in Net Profits Plan liability	(1,776)		(1,925)
Derivative loss	(97,662)	[1]	(30,572)	[1]
Other operating expense	8,089		15,794
Total operating expenses	504,086		437,982
Income from operations	128,634		46,198
Non-operating income (expense)
Interest income	26		12
Interest expense	(24,190)		(19,101)
Income before income taxes	104,470		27,109
Income tax expense	(38,863)		(10,382)
Net income	$ 65,607		$ 16,727
Basic weighted-average common shares outstanding	67,056		66,211
Diluted weighted-average common shares outstanding	68,126		67,521
Basic net income per common share	$ 0.98		$ 0.25
Diluted net income per common share	$ 0.96		$ 0.25
Dividends per common share	$ 0.05		$ 0.05

[1] (2) Total derivative loss is reported in the derivative loss line item on the condensed consolidated statements of cash flows within cash provided by operating activities.