CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
OPERATING ACTIVITIES
Net income	$ 195,113	$ 218,363	$ 7,217
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	108,123	83,017	72,686
Stock-based compensation expense	7,881	6,375	6,576
Gain on disposition of assets, net	(9,344)	(8,804)	(10,882)
Deferred income tax provision	8,647	19,496	4,888
Pension settlement charges	18,286	2,921
Other non-cash adjustments	126	647	(180)
(Increase) decrease in assets:
Accounts receivable	104,574	(157,894)	(91,082)
Income taxes receivable	(9,866)	16,101	24,439
Inventories	(12,341)	(18,413)	3,951
Prepaid expenses	5,233	(7,980)	(650)
Other current assets	311	406	90
Other non-current assets	(1,285)	9,306	(1,170)
Increase (decrease) in liabilities:
Accounts payable	(34,519)	35,759	32,900
Income taxes payable	(224)	(157)	(459)
Unearned Revenue	15,743
Accrued payroll and related expenses	(2,223)	17,864	(3,080)
Pension liabilities	(5,419)
Accrued insurance expenses	2,108	(6,897)	4,640
Accrued state, local and other taxes	165	2,391	(883)
Other accrued expenses	(5,732)	(3,703)	(4,061)
Pension and retirement plan liabilities	618	(4,589)	(1,065)
Long-term accrued insurance expenses	3,053	(4,621)	(52)
Other long-term liabilities	5,735	1,698	3,896
Net cash provided by operating activities	394,763	201,286	47,719
INVESTING ACTIVITIES
Capital expenditures	(181,005)	(139,552)	(67,645)
Proceeds from sale of assets	18,091	15,837	20,014
Purchase of business	(78,798)
Net cash used for investing activities	(241,712)	(123,715)	(47,631)
FINANCING ACTIVITIES
Payment of dividends	(34,562)	(8,645)
Cash paid for common stock purchased and retired	(21,088)	(918)	(567)
Cash paid for finance lease and finance obligations	(515)	(24,017)	(1,584)
Net cash used for financing activities	(56,165)	(33,580)	(2,151)
Net increase (decrease) in cash and cash equivalents	96,886	43,991	(2,063)
Cash and cash equivalents at beginning of period	126,424	82,433	84,496
Cash and cash equivalents at end of period	223,310	126,424	82,433
Supplemental cash flows disclosure:
Income tax payments, net	62,226	35,809	(20,903)
Interest paid	166	170	166
Supplemental disclosure of noncash investing activities:
Capital expenditures included in accounts payable	$ 9,036	$ 9,334	$ 4,282