Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net loss	$ (57,840)	$ (27,722)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	59,937	42,003
Stock-based compensation	3,637	985
Stock-based payments	(601)	0
Deferred taxes	(7,145)	(16,116)
Loss (gain) on derivative financial instruments	54,852	(6,505)
Settlements of derivative financial instruments	(16,323)	4,894
Impairment of oil and natural gas properties	12,169	27,081
Loss on abandoned property and equipment	171	0
Non-cash interest expense	4,556	4,375
Unrealized loss (gain) on warrants	2,105	(3,286)
Changes in operating assets and liabilities:
Accounts receivable	(4,596)	(5,214)
Prepaid expenses and other assets	(1,835)	(3,559)
Accounts payable and accrued expenses	6,733	11,531
Net cash provided by operating activities	55,820	28,467
Cash flows from investing activities
Acquisition of oil and gas properties	(4,762)	(109,031)
Development of oil and gas properties	(122,691)	(56,918)
Purchases of other property and equipment	(1,631)	(11,580)
Net cash used in investing activities	(129,084)	(177,529)
Cash flows from financing activities
Proceeds from borrowings and related party borrowings	348,744	102,988
Payments on borrowings and related party borrowings	(273,466)	(27,507)
Proceeds from the sale of preferred stock	0	77,800
Repurchase and retire Class B Common Stock	(10)	0
Cost to issue equity	0	(2,790)
Payments of debt issuance costs	0	(2,685)
Net cash provided by financing activities	75,268	147,806
Net increase in cash and cash equivalents	2,004	(1,256)
Cash and cash equivalents, beginning of the period	2,538	6,068
Cash and cash equivalents, end of the period	4,542	4,812
Supplemental information:
Cash paid for taxes	1,147	2,465
Cash paid for interest	22,324	11,060
Non-cash investing and financing activities:
Preferred stock issued for asset acquisition	0	10,795
Increase in asset retirement obligation	222	2,318
Increase in liabilities for capital expenditures	$ 16,988	$ 1,670