CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net Income	$ 96,254	$ 146,157	$ 400,351	$ 412,384
Other comprehensive income, before tax:
Foreign currency translation adjustments	0	0	0	142
Recognition of previously deferred post-retirement benefit plan costs	1,388	1,031	4,165	3,092
Realized gain on available-for-sale investment during the period	0	0	0	(20,800)
Other comprehensive income (loss), before tax	1,388	1,031	4,165	(17,566)
Income tax effect related to components of other comprehensive income	(356)	(265)	(1,067)	4,520
Other comprehensive income (loss), net of tax	1,032	766	3,098	(13,046)
Comprehensive income	97,286	146,923	403,449	399,338
Comprehensive (income) loss attributable to redeemable noncontrolling interest	(71)	(92)	240	(516)
Total comprehensive income	$ 97,215	$ 146,831	$ 403,689	$ 398,822