CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Net Income (loss)	$ (93,710)	$ 49,569	$ 151,089	$ 293,804
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 $1,233 and $1,000, $3,139 and $3,369, respectively	2,896	1,608	6,558	6,379
Other comprehensive income (loss)	2,896	1,608	6,558	6,379
Comprehensive income (loss)	(90,814)	51,177	157,647	300,183
Subsidiaries [Member]
Net Income (loss)	(67,813)	74,125	213,950	351,959
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 $1,233 and $1,000, $3,139 and $3,369, respectively	4,639	3,757	11,814	12,674
Amortization of treasury interest rate swaps to earnings, net of tax of $26 and $25, $76 and $77, respectively	95	97	290	289
Other comprehensive income (loss)	4,734	3,854	12,104	12,963
Comprehensive income (loss)	$ (63,079)	$ 77,979	$ 226,054	$ 364,922