CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
OPERATING ACTIVITIES
Net income (loss)	$ 62,018	$ (10,388)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and other non-cash charges	39,863	35,589
Stock-based compensation expense	3,192	3,010
Gain on disposition of assets, net	(4,752)	(4,571)
Deferred income tax provision (benefit)	7,788	(4,338)
(Increase) decrease in assets:
Accounts receivable	(98,745)	(18,779)
Income taxes receivable	13,027	31,941
Inventories	(11,172)	1,836
Prepaid expenses	1,054	3,465
Other current assets	540	508
Other non-current assets	5,290	1,191
Increase (decrease) in liabilities:
Accounts payable	23,824	12,168
Income taxes payable	(128)	303
Accrued payroll and related expenses	8,881	2,635
Accrued insurance expenses	(4,530)	(482)
Accrued state, local and other taxes	3,077	1,091
Other accrued expenses	(2,351)	49
Pension and retirement plans liabilities	(4,429)	113
Long-term accrued insurance expenses	(1,840)	(1,341)
Other long-term liabilities	2,246	866
Net cash provided by operating activities	42,853	54,866
INVESTING ACTIVITIES
Capital expenditures	(50,578)	(25,875)
Proceeds from sale of assets	7,148	8,094
Net cash used for investing activities	(43,430)	(17,781)
FINANCING ACTIVITIES
Cash paid for common stock purchased and retired	(910)	(566)
Cash paid for finance lease	(2,713)
Net cash used for financing activities	(3,623)	(566)
Net (decrease) increase in cash and cash equivalents	(4,200)	36,519
Cash and cash equivalents at beginning of period	82,433	84,496
Cash and cash equivalents at end of period	78,233	121,015
Supplemental cash flows disclosure:
Income taxes payment (refund), net	872	(28,386)
Interest paid	123	82
Supplemental disclosure of noncash investing activities:
Capital expenditures included in accounts payable	$ 8,248	$ 4,131