CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
OPERATING ACTIVITIES
Net income	$ 27,467	$ 71,524
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	30,004	24,125
Stock-based compensation expense	1,926	1,802
Gain on disposition of assets, net	(1,214)	(2,936)
Deferred income tax provision	730	2,536
Pension settlement charges		17,375
Other non-cash adjustments	135	6
(Increase) decrease in assets:
Accounts receivable	(4,812)	16,209
Income taxes receivable	6,000	18,057
Inventories	(1,488)	(959)
Prepaid expenses	2,535	1,725
Other current assets	121	141
Other non-current assets	(1,044)	(236)
Increase (decrease) in liabilities:
Accounts payable	19,759	(3,389)
Income taxes payable	1,335	14
Unearned revenue	(15,171)
Accrued payroll and related expenses	(10,163)	(13,193)
Accrued insurance expenses	370	865
Accrued state, local and other taxes	(263)	1,691
Other accrued expenses	(2,168)	(1,074)
Pension and retirement plan liabilities	313	(4,723)
Long-term accrued insurance expenses	400	2,018
Other long-term liabilities	1,787	945
Net cash provided by operating activities	56,559	132,523
INVESTING ACTIVITIES
Capital expenditures	(52,778)	(65,300)
Proceeds from sale of assets	3,772	4,285
Net cash used for investing activities	(49,006)	(61,015)
FINANCING ACTIVITIES
Payment of dividends	(8,621)	(8,679)
Cash paid for common stock purchased and retired	(9,858)	(11,349)
Cash paid for finance lease and finance obligations	(185)
Net cash used for financing activities	(18,664)	(20,028)
Net (decrease) increase in cash and cash equivalents	(11,111)	51,480
Cash and cash equivalents at beginning of period	223,310	126,424
Cash and cash equivalents at end of period	212,199	177,904
Supplemental cash flows disclosure:
Income tax payments, net	187	922
Interest paid	42	41
Supplemental disclosure of noncash investing activities:
Capital expenditures included in accounts payable	$ 11,054	$ 11,866