Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
OPERATING ACTIVITIES:
Net loss	$ (3,754)	$ (6,220)
Deferred income taxes	26	(2,060)
Equity income – Sunrise Energy	(364)	(1,054)
Cash distribution - Sunrise Energy	0	1,125
Depreciation, depletion and amortization	39,973	39,644
Asset impairment	1,588	1,799
Gain on extinguishment of debt	(10,000)	0
Loss on sale of assets	317	38
Unrealized gain on marketable securities	0	(14)
Amortization of debt issuance costs	2,564	2,296
Asset retirement obligations accretion	1,504	1,381
Asset retirement obligations change in estimate	(3,510)	0
Stock-based compensation	1,004	1,211
Change in current assets and liabilities:
Accounts receivable	830	11,166
Inventory	16,964	2,893
Parts and supplies	(1,112)	2,872
Prepaid income taxes	0	1,562
Prepaid expenses	(5,215)	0
Accounts payable and accrued liabilities	10,844	(1,405)
Other	(362)	(3,048)
Cash provided by operating activities	47,974	52,576
INVESTING ACTIVITIES:
Capital expenditures	(28,050)	(20,688)
Proceeds from sale of equipment	525	56
Proceeds from sale of marketable securities	0	2,310
Proceeds from maturities of certificates of deposit	0	245
Investment in Sunrise Energy	0	(113)
Cash used in investing activities	(27,525)	(18,190)
FINANCING ACTIVITIES:
Payments on bank debt	(46,249)	(49,662)
Borrowings of bank debt	(20,250)	(7,250)
Proceeds from PPP note	0	10,000
Debt issuance costs	(418)	(1,903)
Taxes paid on vesting of RSUs	(274)	(75)
Dividends	0	(1,236)
Cash used in financing activities	(26,691)	(35,626)
Decrease in cash, cash equivalents, and restricted cash	(6,242)	(1,240)
Cash, cash equivalents, and restricted cash, beginning of year	12,071	13,311
Cash, cash equivalents, and restricted cash, end of year	5,829	12,071
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH:
Cash and cash equivalents	2,546	8,041
Restricted cash	3,283	4,030
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending Balance	5,829	12,071
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for interest	8,720	10,971
SUPPLEMENTAL NON-CASH FLOW INFORMATION:
Change in capital expenditures included in accounts payable and prepaid expenses	8,520	1,199
Interest Rate Swap [Member]
OPERATING ACTIVITIES:
Change in fair value of derivative	(3,026)	68
Fuel Hedge [Member]
OPERATING ACTIVITIES:
Change in fair value of derivative	$ (297)	$ 322