CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net earnings	$ 69,915	$ 40,621
Adjustments to reconcile net earnings to net cash provided by operations:
Depreciation and amortization	57,642	51,109
Provision for deferred income taxes	9,411	12,573
Amortization of share-based compensation	6,408	5,808
Amortization of major maintenance costs	8,345	6,992
Other	1,607	(2,302)
Decrease in cash flows resulting from changes in operating assets and liabilities, net	(30,040)	(98,321)
Net cash provided by operating activities	123,288	16,480
Cash flows from investing activities:
Capital expenditures	(81,047)	(73,199)
Proceeds from disposition of assets	2,412	8,031
Net cash used in investing activities	(78,635)	(65,168)
Cash flows from financing activities:
Borrowings on bank credit facilities, net	43,575	112,691
Borrowings on long-term debt	0	240,000
Payments on long-term debt	0	(350,000)
Payment of debt issuance costs	(3)	(1,236)
Proceeds from exercise of stock options	1,509	118
Payments related to tax withholding for share-based compensation	(5,284)	(3,555)
Treasury stock purchases	(41,787)	(3,184)
Other	(24)	(24)
Net cash used in financing activities	(2,014)	(5,190)
Increase (decrease) in cash and cash equivalents	42,639	(53,878)
Cash and cash equivalents, beginning of year	32,577	80,577
Cash and cash equivalents, end of period	75,216	26,699
Cash paid during the period:
Interest paid	21,511	20,293
Income taxes paid, net	1,062	694
Operating cash outflow from operating leases	11,256	10,451
Non-cash investing activity:
Capital expenditures included in accounts payable	1,590	(8,197)
Right-of-use assets obtained in exchange for lease obligations	$ 5,088	$ 10,768