Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Supplemental Cash Flow Information [Line Items]
Interest, net	$ 120,431	$ 55,240	$ 72,219
Income taxes paid, net	64,484	5,317	36,295
AFUDC borrowed	10,000	2,200	2,800
Property, plant and equipment additions in accounts payable	46,622	35,637	41,765
Right-of-use assets obtained in exchange for new operating lease liabilities	46,181	39,158	44,490
Debt for equity exchange of retained shares in Knife River	293,239	0	0
Continuing And Discontinued Operations
Supplemental Cash Flow Information [Line Items]
Income taxes paid, net	$ 62,500	$ 26,400	$ 70,900