CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Cash Flows from Operating Activities:
Net income (loss)	$ 7,869	$ (3,963)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	20,051	17,898
Accretion of asset retirement obligation	1,315	1,244
Amortization of deferred financing costs	151	151
Amortization of intangible assets	164	164
Stock-based compensation	2,394	2,557
Lower of cost or net realizable value inventory adjustments	1,754	1,855
Impairment of long-lived assets	1,866	2,208
(Gain) loss on disposal of assets	(1,456)	492
Allowance for doubtful accounts	62	0
Allowance for parts inventory obsolescence	2,041	472
Loss on equity investment	888	0
Equity in loss (earnings) of unconsolidated entities	232	(33)
Changes in operating assets and liabilities:
Trade accounts receivable, net	1,654	459
Other receivables, net	(1,482)	(250)
Inventory, net	13,601	9,326
Prepaid expenses and other current assets	827	2,275
Deferred tax assets, net	0	(1,114)
Accounts payable, accrued liabilities, and accrued employee compensation and benefits	(1,779)	(6,892)
Operating lease liabilities	(490)	(740)
Deferred other income	(1,128)	43,872
Other liabilities	2,326	(703)
Net cash provided by operating activities	50,860	69,278
Cash Flows from Investing Activities:
Additions to property, plant, equipment, mineral properties and other assets	(12,409)	(22,974)
Proceeds from sale of assets	3,482	4,651
Proceeds from redemptions/maturities of investments	1,000	1,500
Other investing, net	2,129	416
Net cash used in investing activities	(5,798)	(16,407)
Cash Flows from Financing Activities:
Repayments of short-term borrowings on credit facility	0	(4,000)
Payments of financing lease	(500)	(500)
Employee tax withholding paid for restricted stock upon vesting	(856)	(775)
Proceeds from exercise of stock options	38	0
Net cash used in financing activities	(1,318)	(5,275)
Net Change in Cash, Cash Equivalents and Restricted Cash	43,744	47,596
Cash, Cash Equivalents, and Restricted Cash, beginning of period	41,898	4,651
Cash, Cash Equivalents, and Restricted Cash, end of period	85,642	52,247
Supplemental disclosure of cash flow information
Interest	225	286
Income taxes	214	5
Amounts included in the measurement of operating lease liabilities	848	792
Accrued purchases for property, plant, equipment, and mineral properties	2,858	2,645
Right-of-use assets exchanged for operating lease liabilities	2,185	0
Right-of-use assets exchanged for financing lease liabilities	$ 524	$ 495