Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net Income	$ 95,632	$ 100,725	$ 255,584	$ 498,825
Other Comprehensive Income (Loss):
Actuarially Determined Long-Term Liability Adjustments (Net of tax: ($111), $274, ($332), $822)	385	(901)	1,155	(2,702)
Unrealized Gain (Loss) on Investments in Available-for-Sale Securities (Net of tax: ($69), $2, ($28), $15)	238	(6)	95	(49)
Other Comprehensive Income (Loss)	623	(907)	1,250	(2,751)
Comprehensive Income (Loss)	$ 96,255	$ 99,818	$ 256,834	$ 496,074