Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 62,101	$ 333,900	$ 423,860
Other comprehensive income (loss), net of tax:
Pension and other postretirement employee benefits	9,569	22,875	42,439
Cash flow hedges	(4,189)	118,015	35,312
Other comprehensive income, net of tax	5,380	140,890	77,751
Comprehensive income	$ 67,481	$ 474,790	$ 501,611