Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Supplemental Cash Flow Information [Abstract]
Interest paid, net	$ 78,780	$ 56,916	$ 54,925
Income taxes paid, net	41,765	62,181	76,689
Property, plant and equipment additions in accounts payable	25,840	22,167	12,672
Right-of-use assets obtained in exchange for new operating lease liabilities	15,811	20,777	14,967
Equity contribution from Centennial related to the Separation	0	0	64,724
Equity contribution to MDU Resources for asset/liability transfers related to the Separation	0	0	(1,537)
MDU Resources’ stock issued in connection with a business combination	0	0	383
Accrual for holdback payment related to a business combination	$ 5,686	$ 0	$ 0

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Amount of increase in right-of-use asset obtained in exchange for operating lease liability.

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The fair value of stock issued in noncash financing activities.

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