CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 83,216	$ 51,295
Adjustments to reconcile net income to net cash provided by operating activities
Provision for doubtful accounts	0	21
Depreciation, depletion, and amortization	8,365	7,667
Debt issuance costs amortization	0	36
Loss on derivative contracts	1,064	0
Cash paid on settlement of derivative contracts	(1,085)	0
Gain on sale of assets	0	(19,713)
Stock-based compensation	754	799
Other	76	71
Changes in operating assets and liabilities	(13,234)	(6,945)
Net cash provided by operating activities	79,156	33,231
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures for property, plant and equipment	(11,959)	(4,389)
Acquisition of assets	(1,431)	(3,545)
Purchase of other property and equipment	(49)	(59)
Proceeds from sale of assets	306	37,900
Net cash provided by (used in) investing activities	(13,133)	29,907
CASH FLOWS FROM FINANCING ACTIVITIES
Reduction of financing lease liability	(197)	(122)
Debt issuance costs	0	(81)
Proceeds from exercise of stock options	70	21
Cash paid for tax obligations on vested stock awards	(235)	(613)
Net cash used in financing activities	(362)	(795)
NET INCREASE IN CASH, CASH EQUIVALENTS and RESTRICTED CASH	65,661	62,343
CASH, CASH EQUIVALENTS and RESTRICTED CASH, beginning of year	139,524	28,266
CASH, CASH EQUIVALENTS and RESTRICTED CASH, end of period	205,185	90,609
Supplemental Disclosure of Cash Flow Information
Cash paid for interest, net of amounts capitalized	(167)
Cash paid for interest, net of amounts capitalized		(106)
Supplemental Disclosure of Noncash Investing and Financing Activities
Purchase of Plant, Property and Equipment in accounts payables and accrued expenses	10,858	1,260
Right-of-use assets obtained in exchange for financing lease obligations	$ 117	$ 363