CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (228,449,000)	$ (18,561,000)
Adjustments to reconcile net loss to net cash provided by operating activities
Provision for doubtful accounts	283,000	(91,000)
Depreciation, depletion, and amortization	42,576,000	81,813,000
Impairment	209,754,000	0
Debt issuance costs amortization	318,000	238,000
Write off of debt issuance costs	0	142,000
(Gain) loss on derivative contracts	(12,467,000)	209,000
Cash received on settlement of derivative contracts	10,577,000	5,078,000
Loss (gains) on sale of assets	78,000	0
Stock-based compensation	749,000	3,104,000
Other	68,000	(57,000)
Changes in operating assets and liabilities	(10,025,000)	(9,402,000)
Net cash provided by operating activities	13,462,000	62,473,000
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures for property, plant and equipment	(6,814,000)	(123,676,000)
Acquisition of assets	0	236,000
Proceeds from sale of assets	1,506,000	852,000
Net cash used in investing activities	(5,308,000)	(122,588,000)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from borrowings	39,000,000	112,596,000
Repayments of borrowings	(37,500,000)	(60,596,000)
Reduction of financing lease liability	(694,000)	(635,000)
Debt issuance costs	0	(901,000)
Cash paid for tax withholdings on vested stock awards	(1,000)	(205,000)
Net cash provided by financing activities	805,000	50,259,000
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS and RESTRICTED CASH	8,959,000	(9,856,000)
CASH, CASH EQUIVALENTS and RESTRICTED CASH, beginning of year	5,968,000	19,645,000
CASH, CASH EQUIVALENTS and RESTRICTED CASH, end of period	14,927,000	9,789,000
Supplemental Disclosure of Cash Flow Information
Cash paid for interest, net of amounts capitalized	(812,000)	(949,000)
Cash received for income taxes	616,000	0
Supplemental Disclosure of Noncash Investing and Financing Activities
Purchase of PP&E in accounts payable	704,000	17,224,000
Right-of-use assets obtained in exchange for financing lease obligations	$ 67,000	$ 2,655,000