CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income (loss)	$ (456,421)	$ (1,015,156)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Impairments and other valuation losses	629,326	1,570,886
Depreciation, depletion and amortization	251,976	434,229
Asset retirement obligation	4,048	3,778
Deferred income taxes	(260,419)	(570,795)
Stock compensation	13,018	10,143
(Gain) loss on derivative instruments	32,808
Settlements on derivative instruments	8,927
Changes in non-current assets and liabilities	2,548	2,942
Other, net	2,644	3,276
Changes in operating assets and liabilities:
Receivables, net	(4,327)	92,473
Other current assets	17,328	16,121
Accounts payable and other current liabilities	(27,752)	(177,352)
Net cash provided by operating activities	213,704	370,545
Cash flows from investing activities:
Oil and gas expenditures	(325,058)	(599,222)
Sales of oil and gas assets and other assets	12,854	9,233
Other capital expenditures	(17,774)	(35,882)
Net cash used by investing activities	(329,978)	(625,871)
Cash flows from financing activities:
Proceeds from sale of common stock		752,100
Financing and underwriting fees	(1)	(22,563)
Dividends paid	(22,655)	(28,129)
Proceeds from exercise of stock options and other	1,287	4,936
Net cash provided by financing activities	(21,369)	706,344
Net change in cash and cash equivalents	(137,643)	451,018
Cash and cash equivalents at beginning of period	779,382	405,862
Cash and cash equivalents at end of period	$ 641,739	$ 856,880