CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (111,405)	$ (135,134)	$ (1,047,109)
Adjustments to reconcile net loss to net cash provided by (used for) operating activities:
Deferred and non-current income taxes	(18,080)	7,105	(155,249)
Loss on sale of oil and gas properties	1,060	14,315	112,085
Impairment of oil and gas properties	43,990	27,134	801,347
Dry hole costs, exploratory lease impairments and other exploration costs		84,144	70,694
Depreciation, depletion and amortization	123,557	141,487	321,323
(Gain) loss on derivative financial instruments	(16,753)	5,356	(2,676)
Cash settlements of derivative financial instruments	9,405	2,120	1,230
Gain on extinguishment of debt		(189,052)	(78,741)
Amortization of debt discount, premium and issuance costs	35,880	17,788	5,144
Interest paid in-kind	38,073	11,860
Stock-based compensation	5,923	4,660	8,149
Income taxes related to equity award vesting			2,044
Decrease (increase) in accounts receivable	(16,128)	(3,651)	30,248
Decrease (increase) in other current assets	(921)	169	8,112
Increase (decrease) in accounts payable and accrued expenses	80,013	(12,029)	(46,515)
Net cash provided by (used for) operating activities	174,614	(23,728)	30,086
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(180,481)	(57,424)	(264,210)
Proceeds from sales of oil and gas properties	1,528	27,855	102,485
Net cash used for investing activities	(178,953)	(29,569)	(161,725)
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings	8,000		790,000
Principal payments on debt	(8,000)		(465,000)
Payments to retire debt		(3,397)	(42,655)
Debt and equity issuance costs		(11,108)	(16,201)
Income tax withholdings related to equity awards	(312)	(313)	(526)
Income taxes related to equity award vesting			(2,044)
Common stock warrants exercised	2	13
Net cash provided by (used for) financing activities	(310)	(14,805)	263,574
Net increase (decrease) in cash and cash equivalents	(4,649)	(68,102)	131,935
Cash and cash equivalents, beginning of the year	65,904	134,006	2,071
Cash and cash equivalents, end of the year	$ 61,255	$ 65,904	$ 134,006