Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Operating activities:
Net income	$ 89,515	$ 67,186
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	13,901	11,130
Amortization	116	1,044
Deferred income taxes	2,305	(1,600)
Provision for credit losses	(1,729)	(134)
Amortization of debt issuance costs	788	0
Stock-based compensation costs	2,870	689
Net unrealized gains on investments	(300)	(315)
Gain on sale of assets	(3,682)	(2,458)
Equity in earnings of unconsolidated affiliates, net of distributions	909	(955)
Changes in current assets and liabilities:
Receivables	(91,194)	(109,058)
Due from related-party	0	(1,920)
Contract assets	(77,453)	2,674
Inventories	(4,302)	(5,865)
Other current assets	1,577	2,830
Contract liabilities, net	23,050	2,626
Accounts payable	60,547	29,552
Due to related-party	0	1,568
Other current liabilities	14,268	4,752
Other noncurrent changes	1,284	2,005
Net cash provided by operating activities	32,470	3,751
Investing activities:
Capital expenditures	(31,623)	(16,517)
Net proceeds from sale or disposition of property	5,635	5,412
Proceeds from insurance contracts	2,174	0
Investments	(1,872)	(391)
Net cash used in investing activities	(25,686)	(11,496)
Financing activities:
Repayment of long-term debt	(7,500)	0
Tax withholding on stock-based compensation	(588)	0
Net amounts received from MDU Resources cash management program	0	31,925
Transfers to CEHI, LLC and MDU Resources	0	(25,425)
Net cash provided by (used in) financing activities	(8,088)	6,500
Decrease in cash, cash equivalents and restricted cash	(1,304)	(1,245)
Cash, cash equivalents and restricted cash - beginning of period	86,012	1,567
Cash, cash equivalents and restricted cash - end of period	84,708	322
Interest paid	10,143	5,717
Income taxes paid, net	29,698	25,618
Purchases of property, plant and equipment included in Accounts payable	$ 868	$ 193