Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Operating activities:
Net income	$ 146,492	$ 108,953
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	21,193	16,961
Amortization of intangible assets	116	1,538
Deferred income taxes	3,911	(5,570)
Provision for credit losses	(1,511)	(51)
Amortization of debt issuance costs	1,182	0
Stock-based compensation costs	4,788	1,034
Net unrealized gains on investments	(566)	(531)
Gain on sale of assets	(5,147)	(5,513)
Equity in earnings of unconsolidated affiliates, net of distributions	(4,091)	(4,788)
Changes in current assets and liabilities:
Receivables	(152,196)	(115,174)
Due from related-party	0	(763)
Contract assets	(83,428)	(10,275)
Inventories	(4,207)	(4,214)
Other current assets	6,335	(2,303)
Contract liabilities, net	62,528	23,833
Accounts payable	75,076	44,265
Due to related-party	0	10
Other current liabilities	36,342	32,760
Other noncurrent changes	1,823	2,510
Net cash provided by operating activities	108,640	82,682
Investing activities:
Capital expenditures	(42,119)	(34,506)
Net proceeds from sale or disposition of property, plant and equipment	8,269	9,587
Proceeds from insurance contracts	2,174	0
Investments	(1,971)	(570)
Net cash used in investing activities	(33,647)	(25,489)
Financing activities:
Repayment of long-term debt	(11,250)	0
Tax withholding on stock-based compensation	(588)	0
Net amounts received from MDU Resources cash management program	0	45,994
Transfers to CEHI, LLC and MDU Resources	0	(104,201)
Net cash used in financing activities	(11,838)	(58,207)
Increase (decrease) in cash, cash equivalents and restricted cash	63,155	(1,014)
Cash, cash equivalents and restricted cash - beginning of period	86,012	1,567
Cash, cash equivalents and restricted cash - end of period	149,167	553
Interest paid	15,083	8,825
Income taxes paid, net	46,245	39,183
Purchases of property, plant and equipment included in Accounts payable	$ 303	$ 293