CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities:
Net income (loss)	$ 239,661,000	$ (318,708,000)
Adjustments to reconcile net income (loss) to net cash provided from operating activities:
Deferred income tax expense (benefit)	170,046,000	(171,464,000)
Depletion, depreciation and amortization and impairment	302,325,000	285,991,000
Exploration dry hole costs	161,000	0
Abandonment and impairment of unproved properties	9,613,000	17,687,000
Derivative fair value (income) loss	(276,752,000)	75,890,000
Cash settlements on derivative financial instruments	(794,000)	207,544,000
Allowance for bad debt	300,000	450,000
Amortization of deferred financing costs, loss on extinguishment of debt and other	2,557,000	3,437,000
Deferred and stock-based compensation	1,952,000	71,718,000
(Gain) loss on the sale of assets	(23,407,000)	4,947,000
Changes in working capital:
Accounts receivable	(13,610,000)	41,955,000
Inventory and other	3,716,000	10,500,000
Accounts payable	18,426,000	(19,194,000)
Accrued liabilities and other	(22,866,000)	(37,552,000)
Net cash provided from operating activities	411,328,000	173,201,000
Investing activities:
Additions to natural gas and oil properties	(469,644,000)	(241,109,000)
Additions to field service assets	(2,966,000)	(1,304,000)
Acreage purchases	(37,987,000)	(23,554,000)
Proceeds from disposal of assets	27,288,000	190,803,000
Purchases of marketable securities held by the deferred compensation plan	(19,665,000)	(22,115,000)
Proceeds from the sales of marketable securities held by the deferred compensation plan	21,356,000	22,997,000
Net cash used in investing activities	(481,618,000)	(74,282,000)
Financing activities:
Borrowings on credit facilities	946,000,000	647,000,000
Repayments on credit facilities	(874,000,000)	(739,000,000)
Repayment of senior notes	(500,000)	0
Debt issuance costs	0	(124,000)
Dividends paid	(9,914,000)	(6,796,000)
Taxes paid for shares withheld	(6,077,000)	(3,597,000)
Change in cash overdrafts	10,839,000	(6,804,000)
Proceeds from the sales of common stock held by the deferred compensation plan	4,148,000	10,313,000
Net cash provided from (used in) financing activities	70,496,000	(99,008,000)
Increase (decrease) in cash and cash equivalents	206,000	(89,000)
Cash and cash equivalents at beginning of period	314,000	471,000
Cash and cash equivalents at end of period	$ 520,000	$ 382,000