Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 12,191	$ 729
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	9,708	7,889
Accretion of asset retirement obligations	41	152
Settlement of asset retirement obligations	(52)	0
Gain on sale of oil and gas properties	(449)	0
Total loss (gain) on derivative contracts, net	5,275	(4,460)
Operating portion of net cash paid in settlement of derivative contracts	(4,275)	(586)
Stock-based compensation	1,940	1,311
Deferred income taxes	249	(38)
Amortization of deferred financing costs	69	79
Changes in assets and liabilities:
Decrease in accounts receivable	737	5,920
Increase in prepaid expenses and other current assets	(314)	(214)
Decrease in accounts payable and accrued expenses	(17,611)	(1,710)
Increase (decrease) in revenues and royalties payable	8,595	(5,161)
Increase in advances	662	455
Net cash provided by operating activities	16,766	4,366
Cash flows from investing activities:
Additions to oil and gas properties	(33,372)	(4,168)
Additions to office and other equipment	(15)	0
Proceeds from sales of oil and gas properties	195	0
Net cash used in investing activities	(33,192)	(4,168)
Cash flows from financing activities:
Proceeds from borrowings	20,000	0
Repayments of borrowings	(15,000)	(392)
Cash paid related to the exchange and cancellation of Class A Common Stock	(468)	0
Deferred financing costs	(3)	0
Net cash provided by (used in) financing activities	4,529	(392)
Net decrease in cash and cash equivalents	(11,897)	(194)
Cash at beginning of period	22,955	10,200
Cash at end of period	11,058	10,006
Cash paid for:
Interest	383	147
Non-cash investing and financing activities:
Accrued capital expenditures	8,967	1,575
Asset retirement obligations	$ (181)	$ 21