CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net Income	$ 200,093	$ 131,940	$ 304,097	$ 266,227
Other comprehensive income, before tax:
Foreign currency translation adjustments	0	0	0	142
Recognition of previously deferred post-retirement benefit plan costs	1,327	1,085	2,777	2,061
Realized gain on available-for-sale investment during the period	0	0	0	(20,800)
Other comprehensive income (loss), before tax	1,327	1,085	2,777	(18,597)
Income tax effect related to components of other comprehensive income	(339)	(279)	(711)	4,785
Other comprehensive income (loss), net of tax	988	806	2,066	(13,812)
Comprehensive income	201,081	132,746	306,163	252,415
Comprehensive loss (income) attributable to redeemable noncontrolling interest	12	(371)	311	(424)
Total comprehensive income	$ 201,093	$ 132,375	$ 306,474	$ 251,991