Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net Income	$ 58,061	$ 167,723	$ 159,952	$ 398,100
Other Comprehensive Income (Loss):
Actuarially Determined Long-Term Liability Adjustments (Net of tax: ($110), $274, ($221), $548)	(385)	900	(770)	1,801
Unrealized Loss on Investments in Available-for-Sale Securities (Net of tax: $5, $77, $41, $13)	(17)	(255)	(143)	(43)
Other Comprehensive Income (Loss)	368	(1,155)	627	(1,844)
Comprehensive Income	$ 58,429	$ 166,568	$ 160,579	$ 396,256