Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities
Net income	$ 1,962	$ 6,883
Adjustments to reconcile net income (loss) to net cash from operating activities:
Accretion of asset retirement obligations	141	128
Depreciation and amortization	5,002	4,116
Amortization of debt issuance costs	14	14
Stock-based compensation	923	894
Deferred income taxes	110	1,341
Changes in operating assets and liabilities:
Accounts receivable	4,836	(16,556)
Prepaid expenses and other current assets	(554)	1,010
Inventories	(8,197)	(842)
Other assets and liabilities	(214)	63
Accounts payable	2,649	(4,159)
Accrued expenses	(256)	1,031
Net cash from operating activities	6,416	(6,077)
Cash flow from investing activities:
Purchases of property, plant and equipment	(8,900)	(8,199)
Cash flows from financing activities
Proceeds from borrowings	22,200	26,500
Repayment of borrowings	(9,533)	(17,251)
Repayments of financed insurance payable	(281)	(171)
Net cash from financing activities	12,386	9,078
Net change in cash and cash equivalents and restricted cash	9,902	(5,198)
Cash and cash equivalents and restricted cash, beginning of period	6,865	7,380
Cash and cash equivalents and restricted cash, end of period	16,767	2,182
Supplemental cash flow information:
Cash paid for interest	242	249
Non-cash investing and financing activities:
Capital expenditures included in accounts payable and accrued expenses	2,689	4,332
Additional asset retirement obligations incurred	$ 9	$ 43