Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (140,499)	$ (157,541)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Depreciation, depletion and amortization	64,287	170,245
Exploration expense	28,952	7,118
Pension benefit costs		76
Stock-based compensation	5,464	3,394
Impairment of proved oil and gas properties	17,665	0
Accretion of asset retirement obligations	275	1,197
(Gain) loss on derivative instruments	8,407	(31,527)
Net cash receipts (payments) on settled derivatives	35,870	23,754
(Gain) loss on sale of assets	(944)	(5,183)
(Gain) loss on early extinguishment of debt	(14,489)	59,392
Deferred income taxes	540	(52,447)
Interest not paid in cash		1,232
Amortization of deferred financing costs	1,457	1,481
Amortization of debt discount	1,033	1,529
Changes in operating assets and liabilities:
Accounts receivable	(1,261)	23,126
Other assets	(1,902)	(619)
Accounts payable and accrued liabilities	(33,342)	15,491
Net cash provided by (used in) operating activities	(28,487)	60,718
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures for oil and gas properties	(92,204)	(410,527)
Capital expenditures for other property and equipment	(852)	(1,327)
Proceeds from sale of assets	14,887	37,287
Net cash used in investing activities	(78,169)	(374,567)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from issuance of long-term debt		538,466
Debt issuance costs	40	(13,232)
Repayments of long-term debt	(23,936)	(485,158)
Proceeds from issuance of common stock	124,361	440,000
Equity issuance costs	(484)	(5,875)
Employee tax withholding for settlement of equity compensation awards	(61)
Net cash provided by financing activities	99,920	474,201
Net increase (decrease) in cash and cash equivalents	(6,736)	160,352
Cash and cash equivalents at beginning of period	184,405	67,517
Cash and cash equivalents at end of period	177,669	227,869
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for interest	48,101	39,125
Cash paid for income taxes		284
SUPPLEMENTAL DISCLOSURE OF NON-CASH ACTIVITIES
Asset retirement obligations incurred, including changes in estimate	923	495
Additions of other property through debt financing		888
Additions to oil and natural gas properties - changes in accounts payable, accrued liabilities, and accrued capital expenditures	$ 26,055	(120,751)
Interest paid-in-kind		$ 14,786