CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net income	$ 17,941,000	$ 111,961,000
Adjustments to reconcile net income to net cash provided from operating activities:
Deferred income tax expense	38,295,000	98,054,000
Depletion, depreciation and amortization and impairment	510,172,000	525,753,000
Exploration dry hole costs	4,000	9,166,000
Abandonment and impairment of unproved properties	73,244,000	52,181,000
Derivative fair value loss (income)	151,890,000	(188,326,000)
Cash settlements on derivative financial instruments	(40,272,000)	16,062,000
Allowance for bad debts	(1,250,000)	1,050,000
Amortization of deferred financing costs and other	4,163,000	4,184,000
Deferred and stock-based compensation	41,252,000	3,937,000
Gain on the sale of assets	(149,000)	(23,509,000)
Changes in working capital:
Accounts receivable	(49,713,000)	(39,694,000)
Inventory and other	(822,000)	(1,504,000)
Accounts payable	(6,529,000)	44,715,000
Accrued liabilities and other	36,721,000	(13,498,000)
Net cash provided from operating activities	774,947,000	600,532,000
Investing activities:
Additions to natural gas and oil properties	(781,554,000)	(771,067,000)
Additions to field service assets	(1,230,000)	(4,687,000)
Acreage purchases	(50,461,000)	(46,967,000)
Proceeds from disposal of assets	24,339,000	27,583,000
Purchases of marketable securities held by the deferred compensation plan	(34,953,000)	(25,410,000)
Proceeds from the sales of marketable securities held by the deferred compensation plan	37,311,000	28,755,000
Net cash used in investing activities	(806,548,000)	(791,793,000)
Financing activities:
Borrowings on credit facilities	1,602,000,000	1,486,000,000
Repayments on credit facilities	(1,547,000,000)	(1,282,000,000)
Repayment of senior notes	0	(500,000)
Dividends paid	(14,950,000)	(14,876,000)
Debt issuance costs	(8,257,000)	(247,000)
Taxes paid for shares withheld	(3,143,000)	(6,971,000)
Change in cash overdrafts	(5,653,000)	5,588,000
Proceeds from the sales of common stock held by the deferred compensation plan	8,513,000	4,482,000
Net cash provided from financing activities	31,510,000	191,476,000
(Decrease) increase in cash and cash equivalents	(91,000)	215,000
Cash and cash equivalents at beginning of period	448,000	314,000
Cash and cash equivalents at end of period	$ 357,000	$ 529,000