CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Net Income (loss)	$ (31)	$ 278,295
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Net unrealized gain (loss) from pension and postretirement plans, net of tax of $10 and $953, respectively	(658)	1,831
Other comprehensive income (loss)	(658)	1,831
Comprehensive income (loss)	(689)	280,126
Subsidiaries [Member]
Net Income (loss)	27,535	288,081
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Net unrealized gain (loss) from pension and postretirement plans, net of tax of $10 and $953, respectively	36	3,588
Amortization of treasury interest rate swaps to earnings, net of tax of $26 and $26, respectively	97	97
Other comprehensive income (loss)	133	3,685
Comprehensive income (loss)	$ 27,668	$ 291,766