CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net income	$ 8,154	$ 2,020
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	9,514	3,820
Amortization of deferred loan costs	293	134
Stock-based compensation	1,280	873
Provision for bad debts	(39)	(76)
Non cash operating lease expense	(4)
Deferred income taxes	1
Changes in operating assets and liabilities:
Receivables	(4,025)	1,188
Income taxes	1,511	91
Inventories	855	(154)
Prepaid expenses	1,071	845
Accounts payable	703	(10,458)
Accrued expenses	2,462	(5,901)
Net cash provided by (used in) operating activities	21,854	(7,466)
Cash flows from investing activities:
Change in construction payable	497	(2,876)
Acquisition of property and equipment	(6,427)	(10,839)
Net cash used in investing activities	(5,930)	(13,715)
Cash flows from financing activities:
Proceeds from exercise of stock options	2,409
Principal payments on long-term debt	(22,500)
Net cash (used in) provided by financing activities	(20,091)
Change in cash and cash equivalents	(4,167)	(21,181)
Cash and cash equivalents at beginning of period	28,310	60,539
Cash and cash equivalents at end of period	24,143	$ 39,358
Supplemental disclosure of cash flow information:
Cash paid for interest, net of amounts capitalized	$ 1,328