Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive (Loss) Income
Beginning balance at Dec. 31, 2023	$ 1,343,442	$ 299	$ 547,861	$ 944,342	$ (149,060)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	101,891			101,891
Actuarially Determined Long-Term Liability Adjustments	385				385
Investments in Available-for-Sale Securities	(126)				(126)
Comprehensive Income (Loss)	102,150			101,891	259
Issuance of Common Stock	0	1	(1)
Repurchases of Common Stock	(55,881)	(6)	(11,264)	(44,611)
Excise Tax on Repurchases of Common Stock	(471)			(471)
Employee Stock-Based Compensation	5,129		5,118	11
Shares Withheld for Taxes	(5,551)		(5,551)
Ending balance at Mar. 31, 2024	1,388,818	294	536,163	1,001,162	(148,801)
Beginning balance at Dec. 31, 2023	1,343,442	299	547,861	944,342	(149,060)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	255,584
Actuarially Determined Long-Term Liability Adjustments	1,155
Investments in Available-for-Sale Securities	95
Comprehensive Income (Loss)	256,834
Ending balance at Sep. 30, 2024	1,529,495	294	538,054	1,138,957	(147,810)
Beginning balance at Mar. 31, 2024	1,388,818	294	536,163	1,001,162	(148,801)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	58,061			58,061
Actuarially Determined Long-Term Liability Adjustments	385				385
Investments in Available-for-Sale Securities	(17)				(17)
Comprehensive Income (Loss)	58,429			58,061	368
Issuance of Common Stock	0	1	(1)
Repurchases of Common Stock	(10,997)	(1)	(2,407)	(8,589)
Excise Tax on Repurchases of Common Stock	(82)			(82)
Employee Stock-Based Compensation	2,262		2,237	25
Shares Withheld for Taxes	(27)		(27)
Ending balance at Jun. 30, 2024	1,438,403	294	535,965	1,050,577	(148,433)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	95,632			95,632
Actuarially Determined Long-Term Liability Adjustments	385				385
Investments in Available-for-Sale Securities	238				238
Comprehensive Income (Loss)	96,255			95,632	623
Excise Tax on Repurchases of Common Stock	2			2
Employee Stock-Based Compensation	2,252		2,051	201
Shares Withheld for Taxes	38		38
Dividends on Common Shares	(7,348)			(7,348)
Dividend Equivalents Earned on Stock-Based Compensation Awards	(107)			(107)
Ending balance at Sep. 30, 2024	1,529,495	294	538,054	1,138,957	(147,810)
Beginning balance at Dec. 31, 2024	1,568,247	294	540,412	1,162,114	(134,573)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	(69,277)			(69,277)
Actuarially Determined Long-Term Liability Adjustments	378				378
Investments in Available-for-Sale Securities	(301)				(301)
Comprehensive Income (Loss)	(69,200)			(69,277)	77
Issuance of Common Stock	0	3	(3)
Merger with Arch	2,481,368	243	2,481,125
Repurchases of Common Stock	(101,259)	(14)	(25,296)	(75,949)
Employee Stock-Based Compensation	36,094		36,094
Shares Withheld for Taxes	(14,068)		(14,068)
Dividends on Common Shares	(5,364)			(5,364)
Dividend Equivalents Earned on Stock-Based Compensation Awards	(44)			(44)
Ending balance at Mar. 31, 2025	3,895,774	526	3,018,264	1,011,480	(134,496)
Beginning balance at Dec. 31, 2024	1,568,247	294	540,412	1,162,114	(134,573)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	(74,235)
Actuarially Determined Long-Term Liability Adjustments	1,134
Investments in Available-for-Sale Securities	569
Comprehensive Income (Loss)	(72,532)
Ending balance at Sep. 30, 2025	3,778,794	512	2,991,513	919,639	(132,870)
Beginning balance at Mar. 31, 2025	3,895,774	526	3,018,264	1,011,480	(134,496)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	(36,556)			(36,556)
Actuarially Determined Long-Term Liability Adjustments	378				378
Investments in Available-for-Sale Securities	464				464
Comprehensive Income (Loss)	(35,714)			(36,556)	842
Repurchases of Common Stock	(81,893)	(11)	(21,597)	(60,285)
Excise Tax on Repurchases of Common Stock	(1,245)			(1,245)
Employee Stock-Based Compensation	(4,067)		(4,067)	0
Dividends on Common Shares	(5,223)			(5,223)
Dividend Equivalents Earned on Stock-Based Compensation Awards	(46)			(46)
Ending balance at Jun. 30, 2025	3,767,586	515	2,992,600	908,125	(133,654)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	31,598			31,598
Actuarially Determined Long-Term Liability Adjustments	378				378
Investments in Available-for-Sale Securities	406				406
Comprehensive Income (Loss)	32,382			31,598	784
Repurchases of Common Stock	(19,439)	(3)	(5,003)	(14,433)
Excise Tax on Repurchases of Common Stock	(523)			(523)
Employee Stock-Based Compensation	3,916		3,916	0
Dividends on Common Shares	(5,128)			(5,128)
Ending balance at Sep. 30, 2025	$ 3,778,794	$ 512	$ 2,991,513	$ 919,639	$ (132,870)