CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (44,373)	$ (51,725)
Adjustments to reconcile net loss to net cash provided by (used for) operating activities:
Deferred income taxes	855	4,519
Net loss on sale of oil and gas properties		907
Exploratory lease impairments		7,753
Impairment of oil and gas properties		24,460
Depreciation, depletion and amortization	60,226	74,865
Gain on derivative financial instruments	(13,155)	(674)
Cash settlements of derivative financial instruments	1,896	2,120
Gain on extinguishment of debt		(89,576)
Amortization of debt discount, premium and issuance costs	15,000	2,533
Interest paid in-kind	18,594
Stock-based compensation	2,815	2,493
Decrease (increase) in accounts receivable	(9,657)	331
Increase in other current assets	(908)	(346)
Increase (decrease) in accounts payable and accrued expenses	24,222	(8,864)
Net cash provided by (used for) operating activities	55,515	(31,204)
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(85,829)	(33,654)
Proceeds from sales of oil and gas properties		2,067
Net cash used for investing activities	(85,829)	(31,587)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments to retire debt		(3,397)
Common stock warrants exercised	2
Debt and equity issuance costs		(93)
Tax withholdings related to equity awards	(271)	(313)
Net cash used for financing activities	(269)	(3,803)
Net decrease in cash and cash equivalents	(30,583)	(66,594)
Cash and cash equivalents, beginning of period	65,904	134,006
Cash and cash equivalents, end of period	$ 35,321	$ 67,412