CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (12,670)	$ (5,277)
Adjustments to reconcile net loss to net cash provided by operating activities
Provision for doubtful accounts	283	72
Depreciation, depletion, and amortization	27,489	39,408
Impairment	7,970	0
Debt issuance costs amortization	159	117
(Gain) loss on derivative contracts	(10,226)	209
Cash received on settlement of derivative contracts	4,087	5,078
Stock-based compensation	169	996
Other	156	(35)
Changes in operating assets and liabilities	686	(8,998)
Net cash provided by operating activities	18,103	31,570
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures for property, plant and equipment	(5,452)	(62,254)
Acquisition of assets	0	326
Proceeds from sale of assets	989	341
Net cash used in investing activities	(4,463)	(61,587)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from borrowings	21,000	39,596
Repayments of borrowings	(32,500)	(19,596)
Reduction of financing lease liability	(366)	(293)
Cash paid for tax withholdings on vested stock awards	(1)	0
Net cash (used in) provided by financing activities	(11,867)	19,707
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS and RESTRICTED CASH	1,773	(10,310)
CASH, CASH EQUIVALENTS and RESTRICTED CASH, beginning of year	5,968	19,645
CASH, CASH EQUIVALENTS and RESTRICTED CASH, end of period	7,741	9,335
Supplemental Disclosure of Cash Flow Information
Cash paid for interest, net of amounts capitalized	(540)	(408)
Cash received for income taxes	616	0
Supplemental Disclosure of Noncash Investing and Financing Activities
Purchase of PP&E in accounts payable	1,066	43,425
Right-of-use assets obtained in exchange for financing lease obligations	$ 67	$ 1,992