CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
OPERATING ACTIVITIES
Net income (loss)	$ 15,079	$ (9,662)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and other non-cash charges	19,343	17,800
Stock-based compensation expense	1,497	1,539
Gain on disposition of assets, net	(2,954)	(1,460)
Deferred income tax provision (benefit)	6,975	(752)
(Increase) decrease in assets:
Accounts receivable	(26,586)	(25,076)
Income taxes receivable	1,056	331
Inventories	(5,326)	2,800
Prepaid expenses	(3,771)	1,097
Other current assets	677	614
Other non-current assets	2,875	2,735
Increase (decrease) in liabilities:
Accounts payable	(168)	18,155
Income taxes payable	326	187
Accrued payroll and related expenses	6,529	4,638
Accrued insurance expenses	(4,749)	(1,046)
Accrued state, local and other taxes	1,091	1,751
Other accrued expenses	(1,746)	(1,611)
Pension liabilities	(2,548)	(1,788)
Long-term accrued insurance expenses	(1,142)	(1,279)
Other long-term liabilities	1,790	291
Net cash provided by operating activities	8,248	9,264
INVESTING ACTIVITIES
Capital expenditures	(19,084)	(11,750)
Proceeds from sale of assets	3,825	3,968
Net cash used for investing activities	(15,259)	(7,782)
FINANCING ACTIVITIES
Cash paid for common stock purchased and retired	(910)	(557)
Cash paid for finance lease	(1,323)
Net cash used for financing activities	(2,233)	(557)
Net (decrease) increase in cash and cash equivalents	(9,244)	925
Cash and cash equivalents at beginning of period	82,433	84,496
Cash and cash equivalents at end of period	73,189	85,421
Supplemental cash flows disclosure:
Income taxes refund, net	333	481
Interest paid	43	42
Supplemental disclosure of noncash investing activities:
Capital expenditures included in accounts payable	$ 7,020	$ 5,271