CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Operating activities:
Net (loss) income	$ (38,901)	$ 185,904
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation, depletion and amortization	88,732	84,081
Amortization of acquired intangibles, net	2,714	3,350
Amortization of debt issuance costs and accretion of debt discount	579	559
Loss (gain) on disposal of assets	138	(321)
Accretion on asset retirement obligations	11,122	12,400
Employee benefit plans, net	11,628	9,592
Deferred income taxes	(12,663)	6,341
Stock-based compensation	7,455	6,304
Equity loss in affiliates	13,696	7,557
Other, net	(214)	(516)
Changes in operating assets and liabilities	(8,874)	18,948
Net cash provided by operating activities	75,412	334,199
Investing activities:
Capital expenditures	(73,092)	(124,718)
Proceeds from disposal of assets	95	594
Purchases of investment securities	(29,303)	(26,940)
Sales and maturities of investment securities	30,630	26,179
Capital contributions to equity affiliates	(23,509)	(15,659)
Other, net	12	13
Net cash used in investing activities	(95,167)	(140,531)
Financing activities:
Principal repayments of long-term debt	(865)	(1,191)
Debt issuance costs	(2,142)	0
Dividend equivalents paid	(415)	(3,077)
Common stock repurchases and related expenses	(5,155)	(117,648)
Other, net	(696)	(622)
Net cash used in financing activities	(9,273)	(122,538)
Net (decrease) increase in cash and cash equivalents and restricted cash	(29,028)	71,130
Cash and cash equivalents and restricted cash at beginning of period	604,161	384,125
Cash and cash equivalents and restricted cash at end of period	575,133	455,255
Supplemental disclosure of noncash investing and financing activities:
Accrued capital expenditures	7,831	6,379
Accrued common stock repurchases and stock repurchase excise tax	$ 0	$ 4,652