Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
OPERATING ACTIVITIES:
Net loss	$ (1,032)	$ (3,660)
Deferred income taxes	(1,729)	(1,652)
Equity income – Sunrise Energy	0	(55)
Depreciation, depletion and amortization	10,307	10,627
Unrealized gain on marketable securities	0	(14)
Amortization of debt issuance costs	611	467
Asset retirement obligations accretion	363	333
Stock-based compensation	282	319
Change in current assets and liabilities:
Accounts receivable	781	12,885
Inventory	(9,373)	(9,113)
Parts and supplies	(385)	889
Prepaid income taxes	0	581
Prepaid expenses	(242)	159
Accounts payable and accrued liabilities	4,342	(1,691)
Other	135	2,277
Cash provided by operating activities	2,973	16,256
INVESTING ACTIVITIES:
Investment in Sunrise Energy	0	(112)
Capital expenditures	(5,720)	(6,022)
Proceeds from sale of marketable securities	0	2,310
Proceeds from maturities of certificates of deposit	0	245
Cash used in investing activities	(5,720)	(3,579)
FINANCING ACTIVITIES:
Payments on bank debt	(9,188)	(12,100)
Borrowings of bank debt	7,500	0
Taxes paid on vesting of RSUs	(2)	0
Dividends paid	0	(1,236)
Cash used in financing activities	(1,690)	(13,336)
Decrease in cash, cash equivalents, and restricted cash	(4,437)	(659)
Cash, cash equivalents, and restricted cash, beginning of period	12,071	13,311
Cash, cash equivalents, and restricted cash, end of period	7,634	12,652
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH CONSIST OF THE FOLLOWING:
Cash and cash equivalents	3,863	7,918
Restricted cash	3,771	4,734
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending Balance	7,634	12,652
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for interest	2,145	2,707
SUPPLEMENTAL NON-CASH FLOW INFORMATION:
Change in capital expenditures included in accounts payable and prepaid expense	1,872	3,516
Interest Rate Swap [Member]
OPERATING ACTIVITIES:
Change in fair value of derivative	(848)	2,593
Fuel Hedge [Member]
OPERATING ACTIVITIES:
Change in fair value of derivative	$ (239)	$ 1,311