Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net income (loss)	$ 21,120	$ (162)
Adjustments to reconcile net income (loss) to net cash from operating activities:
Accretion of asset retirement obligations	461	428
Depreciation and amortization	18,861	15,601
Amortization of debt issuance costs	96	43
Stock-based compensation	3,919	3,119
Other income - employee retention tax credit	(5,407)
Other income - PPP Loan		(8,444)
Deferred income taxes	1,650	(37)
Changes in operating assets and liabilities:
Accounts receivable	(17,293)	(2,030)
Prepaid expenses and other current assets	5,611	630
Inventories	(1,933)	(8,027)
Other assets and liabilities	760	(1,154)
Accounts payable	7,515	3,409
Accrued expenses	2,397	(2,429)
Net cash from operating activities	37,757	947
Cash flow from investing activities:
Purchases of property, plant and equipment	(17,642)	(20,515)
Net cash from investing activities	(17,642)	(20,515)
Cash flows from financing activities
Proceeds from PPP Loan		8,444
Proceeds from borrowings	50,545	45,543
Payments of debt issuance cost	(2,356)
Repayments of borrowings	(24,900)	(32,597)
Repayments of financed insurance payable	(862)	(656)
Repayments of financing leased equipment	(1,253)
Restricted stock surrendered for withholding taxes payable	(327)	(193)
Net cash from financing activities	20,847	20,541
Net change in cash and cash equivalents and restricted cash	40,962	973
Cash and cash equivalents and restricted cash, beginning of period	6,710	6,865
Cash and cash equivalents and restricted cash, end of period	47,672	7,838
Supplemental cash flow information:
Cash paid for interest	852	820
Non-cash investing and financing activities:
Leased assets obtained under new financing leases	9,157
Capital expenditures included in accounts payable and accrued expenses	3,128	633
Additional asset retirement obligations incurred	$ 235	$ 172