CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income (loss)	$ (447,710)	$ 666,051	$ 170,935
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Net gain on divestiture activity	(43,031)	(646)	(27,974)
Depletion, depreciation, amortization, and asset retirement obligation liability accretion	921,009	767,532	822,872
Exploratory dry hole expense	36,612	44,427	5,846
Impairment of proved properties	468,679	84,480	172,641
Abandonment and impairment of unproved properties	78,643	75,638	46,105
Impairment of other property and equipment	49,369	0	0
Stock-based compensation expense	27,467	32,694	32,347
Change In Net Profits Plan Liability	(19,525)	(29,849)	(21,842)
Derivative gain	(408,831)	(583,264)	(3,080)
Derivative settlement gain	512,566	12,615	22,062
Amortization of deferred financing costs	7,710	6,146	5,390
Non-cash loss on extinguishment of debt	4,123	0	0
Deferred income taxes	(276,722)	397,780	105,555
Plugging and abandonment	(7,496)	(8,796)	(9,946)
Other, net	13,761	1,069	2,775
Changes in current assets and liabilities:
Accounts receivable	140,200	24,088	(79,398)
Prepaid expenses and other	2,563	(1,822)	98
Accounts payable and accrued expenses	(86,267)	9,466	91,516
Accrued derivative settlements	5,232	(41,034)	2,612
Net Cash Provided by Operating Activities	978,352	1,456,575	1,338,514
Cash flows from investing activities:
Net proceeds from the sale of oil and gas properties	357,938	43,858	424,849
Capital expenditures	(1,493,608)	(1,974,798)	(1,553,536)
Acquisition of proved and unproved oil and gas properties	(7,984)	(544,553)	(61,603)
Other, net	(985)	(3,256)	(2,613)
Net Cash Used in Investing Activities	(1,144,639)	(2,478,749)	(1,192,903)
Cash flows from financing activities:
Proceeds from credit facility	1,872,500	1,285,500	1,203,000
Repayment of credit facility	(1,836,500)	(1,119,500)	(1,543,000)
Debt issuance costs related to credit facility	0	(3,388)	(3,444)
Net proceeds from Senior Notes	490,951	589,991	490,185
Repayment of Senior Notes	350,000	0	0
Proceeds from sale of common stock	4,844	4,877	6,858
Dividends paid	(6,772)	(6,723)	(6,663)
Net share settlement from issuance of stock awards	(8,678)	(10,624)	(16,220)
Other, net	(160)	(87)	(5)
Net Cash Provided by Financing Activities	166,185	740,046	130,711
Net change in cash and cash equivalents	(102)	(282,128)	276,322
Cash and cash equivalents at beginning of period	120	282,248	5,926
Cash and cash equivalents at end of period	18	120	282,248
Supplemental schedule of additional cash flow information and non-cash activities:
Cash paid for interest, net of capitalized interest	126,988	89,145	70,702
Net cash paid (refunded) for income taxes	$ 1,630	$ 1,936	$ (204)