Knife River (KNF) 10-Q 7 May 24 2024 Q1 Quarterly report Financial data

Cover page

Cover page - shares	3 Months Ended
	Mar. 31, 2024	May 02, 2024
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	1-41642
Entity Registrant Name	Knife River Corporation
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	92-1008893
Entity Address, Address Line One	1150 West Century Avenue
Entity Address, Address Line Two	P.O. Box 5568
Entity Address, City or Town	Bismarck
Entity Address, State or Province	ND
Entity Address, Postal Zip Code	58506-5568
City Area Code	701
Local Phone Number	530-1400
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	KNF
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity common stock, shares outstanding		56,609,704
Entity Central Index Key	0001955520
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenue:
Revenue	$ 329,590	$ 307,900
Cost of revenue:
Cost of revenue	323,096	303,805
Gross profit	6,494	4,095
Selling, general and administrative expenses	60,221	48,658
Operating loss	(53,727)	(44,563)
Interest expense	13,976	9,495
Other income	3,748	826
Loss before income taxes	(63,955)	(53,232)
Income tax benefit	(16,326)	(11,912)
Net loss	$ (47,629)	$ (41,320)
Net loss per share:
Basic (in dollars per share)	$ (0.84)	$ (0.73)
Diluted (in dollars per share)	$ (0.84)	$ (0.73)
Weighted average common shares outstanding:
Basic (in shares)	56,590	56,566
Diluted (in shares)	56,590	56,566
Construction materials
Revenue:
Revenue	$ 204,095	$ 192,917
Cost of revenue:
Cost of revenue	209,830	194,129
Contracting services
Revenue:
Revenue	125,495	114,983
Cost of revenue:
Cost of revenue	$ 113,266	$ 109,676

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net loss	$ (47,629)	$ (41,320)
Other comprehensive income:
Reclassification adjustment for loss on derivative instruments included in net loss, net of tax of $— and $15 for the three months ended in 2024 and 2023, respectively	0	46
Amortization of postretirement liability losses included in net periodic benefit cost, net of tax of $25 and $15 for the three months ended in 2024 and 2023, respectively	78	47
Other comprehensive income	78	93
Comprehensive loss attributable to common stockholders	$ (47,551)	$ (41,227)

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Reclassification adjustment for loss on derivative instruments included in net income, tax	$ 0	$ 15
Amortization of postretirement liability losses included in net periodic benefit cost, tax	$ 25	$ 15

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Current assets:
Cash, cash equivalents and restricted cash	$ 170,658	$ 262,320	$ 7,218
Receivables, net	183,708	266,785	174,590
Costs and estimated earnings in excess of billings on uncompleted contracts	33,559	27,293	30,974
Due from related-party	0	0	16,860
Inventories	375,783	319,623	373,215
Prepayments and other current assets	54,051	37,522	36,301
Total current assets	817,759	913,543	639,158
Noncurrent assets:
Property, plant and equipment	2,609,594	2,579,734	2,512,655
Less accumulated depreciation, depletion and amortization	1,288,982	1,264,687	1,195,287
Net property, plant and equipment	1,320,612	1,315,047	1,317,368
Goodwill	274,478	274,478	274,540
Other intangible assets, net	10,277	10,821	12,763
Operating lease right-of-use assets	45,832	44,706	43,995
Investments and other	44,685	41,218	38,945
Total noncurrent assets	1,695,884	1,686,270	1,687,611
Total assets	2,513,643	2,599,813	2,326,769
Current liabilities:
Long-term debt - current portion	7,072	7,082	211
Related-party notes payable - current portion	0	0	238,000
Accounts payable	97,379	107,656	80,380
Billings in excess of costs and estimated earnings on uncompleted contracts	50,844	51,376	37,375
Accrued compensation	17,699	48,098	14,010
Accrued Interest	15,459	7,247	0
Due to related-party	0	0	23,521
Current operating lease liabilities	13,282	12,948	12,981
Other accrued liabilities	95,495	112,864	66,677
Total current liabilities	297,230	347,271	473,155
Noncurrent liabilities:
Long-term debt	673,539	674,577	359
Related-party notes payable	0	0	578,060
Deferred income taxes	174,122	174,542	175,077
Noncurrent operating lease liabilities	32,551	31,758	31,013
Other	117,574	105,653	94,336
Total liabilities	1,295,016	1,333,801	1,352,000
Commitments and contingencies
Commitments and contingencies
Stockholders' equity:
Common stock	570	570	800
Other paid-in capital	614,679	614,513	548,174
Retained earnings	618,245	665,874	441,680
MDU Resources common stock held by subsidiary at cost - $538,921 shares at March 31, 2023	0	0	(3,626)
Treasury stock held at cost - 431,136 shares	(3,626)	(3,626)	0
Accumulated other comprehensive loss	(11,241)	(11,319)	(12,259)
Total stockholders' equity	1,218,627	1,266,012	974,769
Total liabilities and stockholders' equity	$ 2,513,643	$ 2,599,813	$ 2,326,769

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - $ / shares	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Statement of Financial Position [Abstract]
Common stock, authorized (in shares)	300,000,000	300,000,000	80,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 10
Common stock, issued (in shares)	57,040,840	57,009,542
Common stock, outstanding (in shares)	56,609,704	56,578,406
Common stock held by subsidiary (in shares)			538,921
Treasury stock held at cost (in shares)	(431,136)	(431,136)

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common Stock	Other Paid-in Capital	Retained Earnings	MDU Resources' Stock Held by Subsidiary	Treasury Stock	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2022		80,000
Beginning balance at Dec. 31, 2022	$ 1,028,589	$ 800	$ 549,106	$ 494,661	$ (3,626)	$ 0	$ (12,352)
Common stock held by subsidiary, beginning balance (in shares) at Dec. 31, 2022					(538,921)
Treasury stock, beginning balance (in shares) at Dec. 31, 2022						0
Net loss	(41,320)			(41,320)
Other comprehensive income	93						93
Stock-based compensation	414		453	(39)
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholding	$ (13,007)		(1,385)	(11,622)
Ending balance (in shares) at Mar. 31, 2023		80,000
Common stock held by subsidiary, ending balance (in shares) at Mar. 31, 2023	(538,921)				(538,921)
Treasury stock, ending balance (in shares) at Mar. 31, 2023						0
Ending balance at Mar. 31, 2023	$ 974,769	$ 800	548,174	441,680	$ (3,626)	$ 0	(12,259)
Beginning balance (in shares) at Dec. 31, 2023	57,009,542	57,009,542
Beginning balance at Dec. 31, 2023	$ 1,266,012	$ 570	614,513	665,874	$ 0	$ (3,626)	(11,319)
Common stock held by subsidiary, beginning balance (in shares) at Dec. 31, 2023					0
Treasury stock, beginning balance (in shares) at Dec. 31, 2023	431,136					(431,136)
Net loss	$ (47,629)			(47,629)
Other comprehensive income	78						78
Stock-based compensation	1,811		1,811
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholding (in shares)		31,298
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholding	$ (1,645)		(1,645)
Ending balance (in shares) at Mar. 31, 2024	57,040,840	57,040,840
Common stock held by subsidiary, ending balance (in shares) at Mar. 31, 2024					0
Treasury stock, ending balance (in shares) at Mar. 31, 2024	431,136					(431,136)
Ending balance at Mar. 31, 2024	$ 1,218,627	$ 570	$ 614,679	$ 618,245	$ 0	$ (3,626)	$ (11,241)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating activities:
Net loss	$ (47,629)	$ (41,320)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, depletion and amortization	32,212	29,629
Deferred income taxes	(311)	(757)
Provision for credit losses	(6)	428
Amortization of debt issuance costs	691	132
Employee stock-based compensation costs	1,811	453
Pension and postretirement benefit plan net periodic benefit cost	303	298
Unrealized gains on investments	(1,212)	(892)
Gains on sales of assets	(1,249)	(2,816)
Equity in losses of unconsolidated affiliates	(4)	(11)
Changes in current assets and liabilities, net of acquisitions:
Receivables	76,816	34,268
Due from related-party	0	(810)
Inventories	(56,160)	(49,938)
Other current assets	(16,528)	(18,391)
Accounts payable	(4,183)	1,880
Due to related-party	0	4,588
Other current liabilities	(39,691)	(36,281)
Pension and postretirement benefit plan contributions	(128)	(150)
Other noncurrent changes	12,058	411
Net cash used in operating activities	(43,210)	(79,279)
Investing activities:
Capital expenditures	(43,689)	(42,409)
Net proceeds from sale or disposition of property and other	1,629	3,221
Investments	(3,009)	(1,566)
Net cash used in investing activities	(45,069)	(40,754)
Financing activities:
Issuance of long-term related-party notes, net	0	131,610
Repayment of long-term debt	(1,738)	(68)
Debt issuance costs	0	(21)
Tax withholding on stock-based compensation	(1,645)	0
Net transfers to Centennial	0	(14,360)
Net cash provided by (used in) financing activities	(3,383)	117,161
Decrease in cash, cash equivalents and restricted cash	(91,662)	(2,872)
Cash, cash equivalents and restricted cash -- beginning of year	262,320	10,090
Cash, cash equivalents and restricted cash -- end of period	$ 170,658	$ 7,218

Background

Background	3 Months Ended
	Mar. 31, 2024
Restructuring and Related Activities [Abstract]
Background	Background Knife River is a people-first construction materials and contracting services company. We provide construction materials and contracting services to build safe roads, bridges, airport runways, and other critical infrastructure needs, that connect people with where they want to go and with the supplies they need. Knife River is one of the leading providers of crushed stone and sand and gravel in the United States and operates across 14 states. We conduct our operations through five reportable segments: Pacific, Northwest, Mountain, Central and Energy Services. In the fourth quarter of 2023, we realigned our reportable segments to better support our operational strategies. As a result, a portion of the Pacific segment’s businesses are now reported under the Energy Services segment. In addition, the North Central and South operating regions have been aggregated into one reportable segment, Central. We also reallocated certain amounts to the operating segments that were previously reported within Corporate Services. All periods have been recast to conform with the revised presentation. See Note 14 for additional information. Separation from MDU Resources On May 31, 2023, MDU Resources completed the previously announced separation of Knife River through the distribution of approximately 90 percent of the outstanding shares of common stock, par value $.01 per share, of Knife River to the stockholders of record of MDU Resources as of the close of business on May 22, 2023. MDU Resources retained approximately 10 percent of the outstanding shares of Knife River common stock. The Distribution was structured as a pro rata distribution of one share of Knife River common stock for every four shares of MDU Resources common stock. In November 2023, MDU Resources disposed of all 5,656,621 retained shares of Knife River common stock in an underwritten public offering. As a result of the Distribution, Knife River is now an independent public company and its common stock is listed under the symbol “KNF” on the New York Stock Exchange. The Separation was completed pursuant to a separation and distribution agreement and other agreements with MDU Resources related to the Separation, including, but not limited to, a tax matters agreement, an employee matters agreement and a transition services agreement. For an interim period following the Separation, certain functions will continue to be provided by MDU Resources under a transition services agreement. For more information on the transition services agreement, see Note 16. We have incurred certain costs in establishing Knife River as an independent, publicly traded company and expect to incur ongoing additional costs associated with operating as an independent, publicly traded company. All share and earnings per share information has been retroactively adjusted for all periods presented to reflect the Distribution.

Basis of presentation

Basis of presentation	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation	Basis of presentation The accompanying consolidated interim financial statements were prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Interim financial statements do not include all disclosures provided in annual financial statements and, accordingly, these financial statements should be read in conjunction with the Company's 2023 Annual Report on Form 10-K ("Annual Report"). The information is unaudited but includes adjustments that are, in the opinion of management, necessary for a fair presentation of the accompanying consolidated interim financial statements and are of a normal recurring nature. Prior to the Separation, Knife River operated as a wholly owned subsidiary of Centennial Energy Holdings, Inc., a direct wholly owned subsidiary of MDU Resources and the direct parent company of Knife River prior to the spinoff ("Centennial") and an indirect, wholly owned subsidiary of MDU Resources and not as a stand-alone company. The accompanying consolidated financial statements and footnotes for the periods prior to the Separation were prepared on a "carve-out" basis using a legal entity approach in conformity with GAAP and were derived from the consolidated financial statements of MDU Resources as if Knife River operated on a stand-alone basis during these periods. All revenues and costs, as well as assets and liabilities, directly associated with our business activities are included in the consolidated financial statements. In the periods prior to the Separation, the consolidated financial statements include expense allocations for certain functions provided by MDU Resources and Centennial, including, but not limited to certain general corporate expenses related to senior management, legal, human resources, finance and accounting, treasury, information technology, communications, procurement, tax, insurance and other shared services. These general corporate expenses are included in the Consolidated Statements of Operations within selling, general and administrative expenses and other income (expense). The amount allocated to Knife River was $4.9 million in selling, general and administrative expenses and $300,000 in other income for the three months ended March 31, 2023. These items were allocated on the basis of direct usage when identifiable, with the remainder principally allocated on the basis of percent of total capital invested or other allocation methodologies that were considered to be a reasonable reflection of the utilization of the services provided to the benefits received, including the following: number of employees paid and stated as cost per check; number of employees served; weighted factor of travel, managed units, national account spending, equipment and fleet acquisitions; purchase order dollars spent and purchase order line count; number of payments, vouchers or unclaimed property reports; labor hours; time tracked; and projected workload. The allocations may not, however, reflect the expenses we would have incurred as a stand-alone company for the periods presented. These costs also may not be indicative of the expenses that we will incur in the future or would have incurred if we had obtained these services from a third party. Prior to the Separation, Knife River participated in Centennial’s centralized cash management program, including its overall financing arrangements. Knife River also had related-party note agreements in place with Centennial for the financing of its capital needs, which are reflected as related-party notes payable on the Consolidated Balance Sheet as of March 31, 2023. Interest expense in the Consolidated Statements of Operations, for the periods prior to the Separation, reflects the allocation of interest on borrowing and funding associated with the related-party note agreements. Upon the completion of the Separation, we implemented our own financing agreements with lenders. For additional information on the Knife River's current debt financing, see Note 12. Related-party transactions between Knife River and MDU Resources or Centennial for general operating activities and intercompany debt have been included in the consolidated financial statements for periods prior to the Separation. Outstanding balances as of the periods presented were reflected on Consolidated Balance Sheets as “Due from related-party” or “Due to related-party” and “Related-party notes payable”. See Note 16 for additional information on related-party transactions. Prior to the Separation, income tax expense and tax balances in the consolidated financial statements were calculated on a separate tax return basis. The separate tax return method applies the accounting guidance for income taxes to the stand-alone financial statements as if Knife River were a separate taxpayer and a standalone enterprise. We believe the assumptions supporting the allocation and presentation of income taxes on a separate return basis are reasonable. As a stand-alone entity, we will file tax returns on our own behalf, and tax balances and effective income tax rate may differ from the amounts reported in the historical periods. Management has also evaluated the impact of events occurring after March 31, 2024, up to the date of issuance of these consolidated interim financial statements on May 7, 2024, that would require recognition or disclosure in the Consolidated Financial Statements. Principles of consolidation For all periods, the consolidated financial statements were prepared in accordance with GAAP and include the accounts of Knife River and its wholly owned subsidiaries. All intercompany accounts and transactions between the businesses comprising Knife River have been eliminated in the accompanying audited consolidated financial statements. Use of estimates The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, at the date of the consolidated financial statements, as well as the reported amounts of revenues and expenses during the reporting period. Estimates are used for items such as long-lived assets and goodwill; fair values of acquired assets and liabilities under the acquisition method of accounting; aggregate reserves; property depreciable lives; tax provisions; revenue recognized using the cost-to-cost measure of progress for contracts; expected credit losses; environmental and other loss contingencies; costs on contracting services contracts; actuarially determined benefit costs; asset retirement obligations; lease classification; present value of right-of-use assets and lease liabilities; and the valuation of stock-based compensation. These estimates are based on management’s best knowledge of current events, historical experience, actions that we may undertake in the future and on various other assumptions that are believed to be reasonable under the circumstances. As additional information becomes available, or actual amounts are determinable, the recorded estimates are revised. Consequently, operating results can be affected by revisions to prior accounting estimates. Cash, cash equivalents and restricted cash We consider all highly liquid investments with an original maturity of three months or less, when purchased, to be cash and cash equivalents. At March 31, 2024, the $170.7 million of cash, cash equivalents and restricted cash on the Consolidated Statements of Cash Flows is comprised of $128.4 million of cash and cash equivalents and $42.3 million of restricted cash. At March 31, 2023, the Company did not have any restricted cash. At December 31, 2023, the $262.3 million of cash, cash equivalents and restricted cash on the Consolidated Statements of Cash Flows is comprised of $219.3 million of cash and cash equivalents and $43.0 million of restricted cash. Restricted cash represents deposits held by our captive insurance company that is required by state insurance regulations to remain in the captive insurance company. Seasonality of operations Some of our operations are seasonal and revenues from, and certain expenses for, such operations may fluctuate significantly among quarterly periods, with lower activity in the winter months and higher activity in the summer months. Accordingly, the interim results for particular segments, and for Knife River as a whole, may not be indicative of results for the full fiscal year or other future periods.

New accounting standards

New accounting standards	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
New accounting standards	New accounting standards The following table provides a brief description of the accounting pronouncements applicable to Knife River and the potential impact on its consolidated financial statements and/or disclosures: Standard Description Standard Effective Date Impact on financial statements/disclosures Recently issued Financial Accounting Standards Board (FASB) accounting standards updates ("ASU") not yet adopted ASU 2023-07 - Improvements to Reportable Segment Disclosures In November 2023, the FASB issued guidance on modifying the disclosure requirements to improve reportable segment disclosure requirements through enhanced disclosures about significant segment expenses. The guidance also expands the interim disclosure requirements. The guidance is to be applied on a retrospective basis to the financial statements and footnotes and early adoption is permitted. Fiscal periods beginning after December 15, 2023 and interim periods beginning after December 31, 2024 The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2024 and interim periods for fiscal year 2025. ASU 2023-09 - Improvements to Income Tax Disclosures In December 2023, the FASB issued guidance on modifying the disclosure requirements to increase transparency about income tax information through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information. The guidance is to be applied on a prospective basis to the financial statements and footnotes, however, retrospective adoption is also permitted. The guidance also permits early adoption. Fiscal periods beginning after December 15, 2024 The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2025.

Receivables and allowance for e

Receivables and allowance for expected credit losses	3 Months Ended
	Mar. 31, 2024
Credit Loss [Abstract]
Receivables and allowance for expected credit loss	Receivables and allowance for expected credit losses Receivables consist primarily of trade and contract receivables for the sale of goods and services net of expected credit losses. A majority of our receivables are due in 30 days or less. The total balance of receivables past due 90 days or more was $12.6 million, $13.7 million and $16.7 million at March 31, 2024, March 31, 2023 and December 31, 2023, respectively. Receivables were as follows: March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Trade receivables $ 107,834 $ 100,487 $ 124,134 Contract receivables 50,427 52,487 112,037 Retention receivables 31,524 27,438 36,782 Receivables, gross 189,785 180,412 272,953 Less expected credit loss 6,077 5,822 6,168 Receivables, net $ 183,708 $ 174,590 $ 266,785 The Company's expected credit losses are determined through a review using historical credit loss experience; changes in asset specific characteristics; current conditions; and reasonable and supportable future forecasts, among other specific account data, and is performed at least quarterly. We develop and document our methodology to determine our allowance for expected credit losses. Risk characteristics used by management may include customer mix, knowledge of customers and general economic conditions of the various local economies, among others. Specific account balances are written off when management determines the amounts to be uncollectible. Management has reviewed the balance reserved through the allowance for expected credit losses and believes it is reasonable. Details of the Company's expected credit losses were as follows: Pacific Northwest Mountain Central Energy Services Total (In thousands) As of December 31, 2023 $ 2,053 $ 1,004 $ 2,293 $ 718 $ 100 $ 6,168 Current expected credit loss provision 177 (223) (47) 87 — (6) Less write-offs charged against the allowance (53) 133 2 3 — 85 At March 31, 2024 $ 2,283 $ 648 $ 2,244 $ 802 $ 100 $ 6,077 Pacific Northwest Mountain Central Energy Services Total (In thousands) As of December 31, 2022 $ 1,945 $ 1,253 $ 1,278 $ 901 $ 100 $ 5,477 Current expected credit loss provision 45 313 164 (90) — 432 Less write-offs charged against the allowance 1 68 18 — — 87 At March 31, 2023 $ 1,989 $ 1,498 $ 1,424 $ 811 $ 100 $ 5,822

Inventories

Inventories	3 Months Ended
	Mar. 31, 2024
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories on the Consolidated Balance Sheets were as follows: March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Finished products $ 242,952 $ 220,234 $ 225,319 Raw materials 95,132 114,735 61,776 Supplies and parts 37,699 38,246 32,528 Total $ 375,783 $ 373,215 $ 319,623 Inventories are valued at the lower of cost or net realizable value using the average cost method. Inventories include production costs incurred as part of our aggregate mining activities. These inventoriable production costs include all mining and processing costs associated with the production of aggregates. Stripping costs incurred during the production phase, which represent costs of removing overburden and waste materials to access mineral deposits, are a component of inventoriable production costs.

Net loss per share

Net loss per share	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Net loss per share	Net loss per share The calculation for basic and diluted earnings per share for any period presented prior to the Separation are based on the number of shares outstanding on May 31, 2023, the Separation and Distribution date. For periods prior to the Separation, it is assumed that there are no dilutive equity instruments as there were no Knife River stock-based awards outstanding at the time. Basic net loss per share is computed by dividing net loss by the weighted average number of shares of common stock outstanding during the applicable period. Diluted earnings per share is computed by dividing net income by the total of the weighted average number of shares of common stock outstanding during the applicable period, plus the effect of non-vested performance shares and restricted stock units. The Company's potentially dilutive securities have been excluded from the computation of diluted net loss per share as the effect would reduce the net loss per share and is considered antidilutive. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share is the same. Weighted average common shares outstanding is comprised of issued shares of 57,040,840 less shares held in treasury of 431,136. Basic and diluted earnings per share are calculated as follows, based on a reconciliation of the weighted-average common shares outstanding on a basic and diluted basis: Three Months Ended March 31, 2024 2023 (In thousands, except per share amounts) Net loss $ (47,629) $ (41,320) Weighted average common shares outstanding - basic 56,590 56,566 Effect of dilutive performance shares and restricted stock units — — Weighted average common shares outstanding - diluted 56,590 56,566 Shares excluded from the calculation of diluted loss per share 179 — Net loss per share - basic $ (.84) $ (.73) Net loss per share - diluted $ (.84) $ (.73)

Accumulated other comprehensive

Accumulated other comprehensive loss	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Accumulated other comprehensive loss	Accumulated other comprehensive loss The after-tax changes in the components of accumulated other comprehensive loss were as follows: Net Unrealized Postretirement Total (In thousands) As of December 31, 2023 $ — $ (11,319) $ (11,319) Amounts reclassified from accumulated other comprehensive loss — 78 78 Net current-period other comprehensive income — 78 78 At March 31, 2024 $ — $ (11,241) $ (11,241) Net Unrealized Postretirement Total (In thousands) As of December 31, 2022 $ (90) $ (12,262) $ (12,352) Amounts reclassified from accumulated other comprehensive loss 46 47 93 Net current-period other comprehensive income 46 47 93 At March 31, 2023 $ (44) $ (12,215) $ (12,259) The following amounts were reclassified out of accumulated other comprehensive loss into net loss. The amounts presented in parenthesis indicate a decrease to net loss on the Consolidated Statements of Operations. The reclassifications were as follows: Three Months Ended Location on Consolidated Statements of Operations March 31, 2024 2023 (In thousands) Reclassification adjustment for loss on derivative instruments included in net loss $ — $ (61) Interest expense — 15 Income taxes — (46) Amortization of postretirement liability losses included in net periodic benefit cost (103) (62) Other income 25 15 Income taxes (78) (47) Total reclassifications $ (78) $ (93)

Revenue from contracts with cus

Revenue from contracts with customers	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenue from contracts with customers	Revenue from contracts with customers Revenue is recognized when a performance obligation is satisfied by transferring control over a product or service to a customer. Revenue includes revenue from the sales of construction materials and contracting services. Revenue is measured based on consideration specified in a contract with a customer and excludes any sales incentives and amounts collected on behalf of third parties. Knife River is considered an agent for certain taxes collected from customers. As such, we present revenues net of these taxes at the time of sale to be remitted to governmental authorities, including sales and use taxes. Revenue for construction materials is recognized at a point in time when delivery of the products has taken place. Contracting revenue is recognized over time using an input method based on the cost-to-cost measure of progress on a project. Disaggregation In the following tables, revenue is disaggregated by category for each segment and includes sales of materials to both third parties and internal customers. Due to consolidation requirements, the internal sales revenues must be eliminated against the construction materials product used in downstream materials and contracting services to arrive at the external operating revenues. We believe this level of disaggregation best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. For more information on the Company’s reportable segments, see Note 14. Three Months Ended March 31, 2024 Pacific Northwest Mountain Central Energy Services Corporate Services and Eliminations Total (In thousands) Aggregates $ 19,549 $ 39,398 $ 9,455 $ 15,871 $ — $ — $ 84,273 Ready-mix concrete 31,220 31,776 13,835 23,024 — — 99,855 Asphalt 2,347 8,237 830 5,059 — — 16,473 Liquid asphalt — — — — 11,035 — 11,035 Other 25,330 3,574 5 1,898 3,062 5,142 39,011 Contracting services public-sector 5,475 36,044 25,859 21,033 — — 88,411 Contracting services private-sector 8,074 15,031 13,803 176 — — 37,084 Internal sales (13,608) (14,908) (3,962) (6,097) (2,981) (4,996) (46,552) Revenues from contracts with customers $ 78,387 $ 119,152 $ 59,825 $ 60,964 $ 11,116 $ 146 $ 329,590 Three Months Ended March 31, 2023 Pacific Northwest Mountain Central Energy Services Corporate Services and Eliminations Total (In thousands) Aggregates $ 18,697 $ 42,573 $ 9,667 $ 12,584 $ — $ — $ 83,521 Ready-mix concrete 26,144 33,905 14,370 22,350 — — 96,769 Asphalt 1,316 6,927 810 4,566 — — 13,619 Liquid asphalt — — — — 8,287 — 8,287 Other 23,420 2,682 2 1,585 2,191 426 30,306 Contracting services public-sector 3,971 17,003 28,238 22,860 — — 72,072 Contracting services private-sector 2,899 25,761 13,445 806 — — 42,911 Internal sales (10,804) (12,932) (5,914) (7,131) (2,222) (582) (39,585) Revenues from contracts with customers $ 65,643 $ 115,919 $ 60,618 $ 57,620 $ 8,256 $ (156) $ 307,900

Uncompleted contracts

Uncompleted contracts	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Uncompleted contracts	Uncompleted contracts The timing of revenue recognition may differ from the timing of invoicing to customers. The timing of invoicing to customers does not necessarily correlate with the timing of revenues being recognized under the cost-to-cost method of accounting. Contracts from contracting services are billed as work progresses in accordance with agreed upon contractual terms. Generally, billing to the customer occurs contemporaneous to revenue recognition. A variance in timing of the billings may result in a contract asset or a contract liability. A contract asset occurs when revenues are recognized under the cost-to-cost measure of progress, which exceeds amounts billed on uncompleted contracts. Such amounts will be billed as standard contract terms allow, usually based on various measures of performance or achievement. A contract liability occurs when there are billings in excess of revenues recognized under the cost-to-cost measure of progress on uncompleted contracts. Contract liabilities decrease as revenue is recognized from the satisfaction of the related performance obligation. The changes in contract assets and liabilities were as follows: March 31, 2024 December 31, 2023 Change Location on Consolidated Balance Sheets (In thousands) Contract assets $ 33,559 $ 27,293 $ 6,266 Costs and estimated earnings in excess of billings on uncompleted contracts Contract liabilities (50,844) (51,376) 532 Billings in excess of costs and estimated earnings on uncompleted contracts Net contract liabilities $ (17,285) $ (24,083) $ 6,798 March 31, 2023 December 31, 2022 Change Location on Consolidated Balance Sheets (In thousands) Contract assets $ 30,974 $ 31,145 $ (171) Costs and estimated earnings in excess of billings on uncompleted contracts Contract liabilities (37,375) (39,843) 2,468 Billings in excess of costs and estimated earnings on uncompleted contracts Net contract liabilities $ (6,401) $ (8,698) $ 2,297 The Company recognized $30.5 million in revenue for the three months ended March 31, 2024, which was previously included in contract liabilities at December 31, 2023. The Company recognized $20.3 million in revenue for the three months ended March 31, 2023, which was previously included in contract liabilities at December 31, 2022. The Company recognized a net increase in revenues of $9.2 million and $3.6 million for the three months ended March 31, 2024 and 2023, respectively, from performance obligations satisfied in prior periods. The remaining performance obligations, also referred to as backlog, include unrecognized revenues that we reasonably expect to be realized. These unrecognized revenues can include: projects that have a written award, a letter of intent, a notice to proceed, an agreed upon work order to perform work on mutually accepted terms and conditions and change orders or claims to the extent management believes additional contract revenues will be earned and are deemed probable of collection. The majority of our contracts for contracting services have an original duration of less than one year. At March 31, 2024, the Company's remaining performance obligations were $959.5 million. We expect to recognize the following revenue amounts in future periods related to these remaining performance obligations: $891.0 million within the next 12 months or less; $59.2 million within the next 13 to 24 months; and $9.3 million in 25 months or more.

Goodwill and other intangible a

Goodwill and other intangible assets	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and other intangible assets	Goodwill and other intangible assets The changes in the carrying amount of goodwill were as follows: Balance at January 1, 2024 Goodwill Acquired During the Year Measurement Period Adjustments Reallocation of Goodwill Balance at March 31, 2024 (In thousands) Pacific $ 32,621 $ — $ — $ — $ 32,621 Northwest 90,978 — — — 90,978 Mountain 26,816 — — — 26,816 North Central 75,879 — — — 75,879 South 38,708 — — — 38,708 Energy Services 9,476 — — — 9,476 Total $ 274,478 $ — $ — $ — $ 274,478 Balance at January 1, 2023 Goodwill Acquired During the Year Measurement Period Adjustments Reallocation of Goodwill Balance at March 31, 2023 (In thousands) Pacific $ 38,339 $ — $ — $ — $ 38,339 Northwest 90,978 — — — 90,978 Mountain 26,816 — — — 26,816 North Central 75,879 — — — 75,879 South 38,708 — — — 38,708 Energy Services 3,820 — — — 3,820 Total $ 274,540 $ — $ — $ — $ 274,540 Balance at January 1, 2023 Goodwill Acquired During the Year Measurement Period Adjustments Reallocation of Goodwill Balance at December 31, 2023 (In thousands) Pacific $ 38,339 $ — $ (62) $ (5,656) $ 32,621 Northwest 90,978 — — — 90,978 Mountain 26,816 — — — 26,816 North Central 75,879 — — — 75,879 South 38,708 — — — 38,708 Energy Services 3,820 — — 5,656 9,476 Total $ 274,540 $ — $ (62) $ — $ 274,478 Other amortizable intangible assets were as follows: March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Customer relationships $ 18,540 $ 18,540 $ 18,540 Less accumulated amortization 9,535 7,801 9,102 9,005 10,739 9,438 Noncompete agreements 3,820 4,039 4,039 Less accumulated amortization 3,315 3,113 3,473 505 926 566 Other 1,796 2,479 2,479 Less accumulated amortization 1,029 1,381 1,662 767 1,098 817 Total $ 10,277 $ 12,763 $ 10,821 Amortization expense for amortizable intangible assets for the three months ended March 31, 2024 and 2023 was $545,000 and $667,000, respectively. Estimated amortization expense for identifiable intangible assets as of March 31, 2024, was: Remainder of 2024 2025 2026 2027 2028 Thereafter (In thousands) Amortization expense $ 1,683 $ 1,918 $ 1,738 $ 1,716 $ 1,672 $ 1,550

Fair value measurements

Fair value measurements	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair value measurements	Fair value measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. The fair value guidance establishes a hierarchy for grouping assets and liabilities, based on the significance of inputs. The estimated fair values of the Company's assets and liabilities measured on a recurring basis are determined using the market approach. Financial instruments measured at fair value on a recurring basis We measure our investments in certain fixed-income and equity securities at fair value with changes in fair value recognized in income. We anticipate using these investments, which consist of insurance contracts, to satisfy our obligations under our unfunded, nonqualified defined benefit and defined contribution plans for the Company's executive officers and certain key management employees, and invests in these fixed-income and equity securities for the purpose of earning investment returns and capital appreciation. These investments, which totaled $27.1 million, $22.4 million and $24.9 million at March 31, 2024 and 2023, and December 31, 2023, respectively, are classified as investments on the Consolidated Balance Sheets. The net unrealized gains on these investments were $1.2 million and $827,000 for the three months ended March 31, 2024 and 2023, respectively. The change in fair value, which is considered part of the cost of the plan, is classified in other income on the Consolidated Statements of Operations. The Company's assets measured at fair value on a recurring basis were as follows: Fair Value Measurements at March 31, 2024, Using Quoted Prices in Significant Significant Balance at March 31, 2024 (In thousands) Assets: Money market funds $ — $ 3,845 $ — $ 3,845 Insurance contracts* — 27,059 — 27,059 Total assets measured at fair value $ — $ 30,904 $ — $ 30,904 * The insurance contracts invest approximately 36 percent in fixed-income investments, 22 percent in common stock of large-cap companies, 16 percent in cash equivalents, 10 percent in common stock of mid-cap companies, 8 percent target date investments, 5 percent in common stock of small-cap companies, 1 percent in international investments, 1 percent in real estate investments and 1 percent in high yield investments. Fair Value Measurements at March 31, 2023, Using Quoted Prices in Significant Significant Balance at March 31, 2023 (In thousands) Assets: Money market funds $ — $ 2,472 $ — $ 2,472 Insurance contracts* — 22,438 — 22,438 Total assets measured at fair value $ — $ 24,910 $ — $ 24,910 * The insurance contracts invest approximately 61 percent in fixed-income investments, 15 percent in common stock of large-cap companies, 8 percent in common stock of mid-cap companies, 7 percent target date investments, 6 percent in common stock of small-cap companies, 2 percent in cash equivalents, and 1 percent in international investments. Fair Value Measurements at December 31, 2023, Using Quoted Prices in Significant Significant Balance at December 31, 2023 (In thousands) Assets: Money market funds $ — $ 3,241 $ — $ 3,241 Insurance contracts* — 24,896 — 24,896 Total assets measured at fair value $ — $ 28,137 $ — $ 28,137 * The insurance contracts invest approximately 40 percent in fixed-income investments, 19 percent in common stock of large-cap companies, 18 percent in cash equivalents, 8 percent in target date investments, 8 percent in common stock of mid-cap companies, 6 percent in common stock of small-cap companies and 1 percent in international investments. The Company’s Level 2 money market funds are valued at the net asset value of shares held at the end of the period, based on published market quotations on active markets, or using other known sources including pricing from outside sources. The estimated fair value of the Company’s Level 2 insurance contracts is based on contractual cash surrender values that are determined primarily by investments in managed separate accounts of the insurer. These amounts approximate fair value. The managed separate accounts are valued based on other observable inputs or corroborated market data. Though we believe the methods used to estimate fair value are consistent with those used by other market participants, the use of other methods or assumptions could result in a different estimate of fair value. Nonfinancial instruments measured at fair value on a nonrecurring basis We apply the provisions of the fair value measurement standard to our nonrecurring, non-financial measurements, including long-lived asset impairments. These assets are not measured at fair value on an ongoing basis but are subject to fair value adjustments only in certain circumstances. We review the carrying value of our long-lived assets, excluding goodwill, whenever events or changes in circumstances indicate that such carrying amounts may not be recoverable. The Company's long-term debt is not measured at fair value on the Consolidated Balance Sheets and the fair value is being provided for disclosure purposes only. The fair value was categorized as Level 2 in the fair value hierarchy and was based on discounted cash flows using current market interest rates. The estimated fair value of the Company's Level 2 long-term debt was as follows: March 31, 2024 December 31, 2023 (In thousands) Carrying amount $ 695,247 $ 696,985 Fair value $ 715,962 $ 725,086 The carrying amounts of our remaining financial instruments included in current assets and current liabilities approximate their fair values.

Debt

Debt	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Debt	Debt Certain debt instruments of the Company contain restrictive covenants and cross-default provisions. In order to borrow under the debt agreements, we must be in compliance with the applicable covenants and certain other conditions, all of which management believes the Company, as applicable, was in compliance with at March 31, 2024. In the event we do not comply with the applicable covenants and other conditions, alternative sources of funding may need to be pursued. Long-term debt Long-term Debt Outstanding Long-term debt outstanding was as follows: Weighted Average Interest Rate at March 31, 2024 March 31, 2024 December 31, 2023 (In thousands) Term loan agreement due on May 31, 2028 7.19 % $ 269,844 $ 271,562 Senior notes due on May 1, 2031 7.75 % 425,000 425,000 Other notes due on January 1, 2061 — % 403 423 Less unamortized debt issuance costs 14,636 15,326 Total long-term debt 680,611 681,659 Less current maturities 7,072 7,082 Net long-term debt $ 673,539 $ 674,577 Schedule of Debt Maturities Long-term debt maturities, which excludes unamortized debt issuance costs, at March 31, 2024, were as follows: Remainder of 2024 2025 2026 2027 2028 Thereafter (In thousands) Long-term debt maturities $ 5,353 $ 10,518 $ 13,750 $ 17,188 $ 223,438 $ 425,000

Cash flow information

Cash flow information	3 Months Ended
	Mar. 31, 2024
Supplemental Cash Flow Information [Abstract]
Cash flow information	Cash flow information Cash expenditures for interest and income taxes were as follows: Three Months Ended March 31, 2024 2023 (In thousands) Interest paid, net $ 5,764 $ 7,081 Income taxes paid, net $ — $ 150 Noncash investing and financing transactions were as follows: Three Months Ended March 31, 2024 2023 (In thousands) Right-of-use assets obtained in exchange for new operating lease liabilities $ 4,802 $ 1,894 Property, plant and equipment additions in accounts payable $ 6,046 $ 2,607

Business segment data

Business segment data	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Business segment data	Business segment data We focus on the vertical integration of our products and services by offering customers a single source for construction materials and related contracting services. We operate in 14 states across the United States through our operating segments: Pacific, Northwest, Mountain, North Central, South and Energy Services. These operating segments are used to determine the Company’s reportable segments, Pacific, Northwest, Mountain, Central and Energy Services, which are based on our method of internal reporting and management of our business. Four of the reportable segments are aligned by key geographic areas due to the production of construction materials and related contracting services and one is based on product line. Each segment is led by a segment manager who reports to the Company’s chief operating officer, who is also the Company's chief operating decision maker, along with the chief executive officer. The chief operating decision maker evaluates the performance of the segments and allocates resources to them based on earnings before interest, taxes, depreciation, depletion and amortization ("EBITDA"). In the fourth quarter of 2023, we realigned our reportable segments to better support our operational strategies. The liquid asphalt and related services portion of the Pacific segment's businesses are now reported under the Energy Services segment. In addition, the North Central and South operating regions have been aggregated into one reportable segment, Central. We also reallocated certain amounts to the operating segments that were previously reported within Corporate Services. All periods have been recast to conform with the revised presentation. Each geographic segment offers a vertically integrated suite of products and services, including aggregates, ready-mix concrete, asphalt and contracting services, while the Energy Services segment produces and supplies liquid asphalt, primarily for use in asphalt road construction, and is a supplier to some of the other segments. Each geographic segment mines, processes and sells construction aggregates (crushed stone and sand and gravel); produces and sells asphalt; and produces and sells ready-mix concrete as well as vertically integrating its contracting services to support the aggregate-based product lines. Contracting services include heavy-civil construction, asphalt and concrete paving, and site development and grading. Although not common to all locations, the geographic segments also sell cement, merchandise and other building materials and related services . Corporate Services represents the unallocated costs of certain corporate functions, such as accounting, legal, treasury, information technology, human resources and other corporate expenses that support the operating segments. We account for intersegment sales and transfers as if the sales or transfers were to third parties. The accounting policies applicable to each segment are consistent with those used in the audited consolidated financial statements. The information below follows the same accounting policies as described in the audited financial statements and notes included in the Company's 2023 Annual Report. Information on the Company's segments was as follows: Three Months Ended March 31, 2024 2023 (In thousands) External operating revenues: Pacific $ 78,387 $ 65,643 Northwest 119,152 115,919 Mountain 59,825 60,618 Central 60,964 57,620 Energy Services 11,116 8,256 Corporate Services and Eliminations 146 (156) Total external operating revenues $ 329,590 $ 307,900 Intersegment operating revenues: Pacific $ 13,608 $ 10,804 Northwest 14,908 12,932 Mountain 3,962 5,914 Central 6,097 7,131 Energy Services 2,981 2,222 Corporate Services and Eliminations 4,996 582 Total intersegment operating revenues $ 46,552 $ 39,585 EBITDA: Pacific $ (743) $ 148 Northwest 20,154 13,996 Mountain (6,064) (3,753) Central (18,722) (16,899) Energy Services (2,483) (2,977) Corporate Services and Eliminations (12,738) (4,623) Total segment EBITDA $ (20,596) $ (14,108) A reconciliation of consolidated operating revenues to reportable segment operating revenues is as follows: Three Months Ended March 31, 2024 2023 (In thousands) Consolidated operating revenues $ 329,590 $ 307,900 Plus: Intersegment operating revenues 46,552 39,585 Less: Corporate Services revenue 5,142 426 Total reportable segment operating revenues $ 371,000 $ 347,059 A reconciliation of consolidated loss before income taxes to reportable segment EBITDA is as follows: Three Months Ended March 31, 2024 2023 (In thousands) Total consolidated loss before income taxes $ (63,955) $ (53,232) Plus: Depreciation, depletion and amortization 32,212 29,629 Interest expense, net* 11,147 9,495 Less: Corporate Services EBITDA (12,738) (4,623) Total EBITDA for reportable segments $ (7,858) $ (9,485) * Interest, net is interest expense net of interest income.

Commitments and contingencies

Commitments and contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Commitments and contingencies The Company is party to claims and lawsuits arising out of its business and that of its consolidated subsidiaries, which may include, but are not limited to, matters involving property damage, personal injury, and environmental, contractual and statutory obligations. We accrue a liability for those contingencies when the incurrence of a loss is probable and the amount can be reasonably estimated. If a range of amounts can be reasonably estimated and no amount within the range is a better estimate than any other amount, then the minimum of the range is accrued. We do not accrue liabilities when the likelihood that the liability has been incurred is probable but the amount cannot be reasonably estimated or when the liability is believed to be only reasonably possible or remote. For contingencies where an unfavorable outcome is probable or reasonably possible and which are material, we disclose the nature of the contingency and, in some circumstances, an estimate of the possible loss. Accruals are based on the best information available, but in certain situations management is unable to estimate an amount or range of a reasonably possible loss including, but not limited to when: (1) the damages are unsubstantiated or indeterminate, (2) the proceedings are in the early stages, (3) numerous parties are involved, or (4) the matter involves novel or unsettled legal theories. At March 31, 2024 and 2023, and December 31, 2023, we accrued contingent liabilities as a result of litigation, which have not been discounted, of $1.2 million, $2.0 million and $873,000, respectively. At March 31, 2024 and 2023 and December 31, 2023, we also recorded corresponding insurance receivables of $400,000, $1.3 million and $42,000, respectively, related to the accrued liabilities. Most of these claims and lawsuits are covered by insurance, thus the Company's exposure is typically limited to its deductible amount. Management will continue to monitor each matter and adjust accruals as might be warranted based on new information and further developments. Management believes that the outcomes with respect to probable and reasonably possible losses in excess of the amounts accrued, net of insurance recoveries, while uncertain, either cannot be estimated or will not have a material effect upon the Company's financial position, results of operations or cash flows. Unless otherwise required by GAAP, legal costs are expensed as they are incurred. Environmental matters The Company is a party to claims for the cleanup of a superfund site in Portland, Oregon. There were no material changes to the environmental matters that were previously reported in the audited financial statements and notes included in the Company's 2023 Annual Report. Guarantees Knife River and certain of its subsidiaries have outstanding obligations to third parties where the Company has guaranteed their performance. These guarantees are related to contracts for contracting services and certain other guarantees. At March 31, 2024, the fixed maximum amounts guaranteed under these agreements aggregated to $11.5 million, all of which have no scheduled maturity date. Certain of the guarantees also have no fixed maximum amounts specified. There were no amounts outstanding under the previously mentioned guarantees at March 31, 2024. Knife River and certain of its subsidiaries have outstanding letters of credit to third parties related to insurance policies, cement purchases and other agreements. At March 31, 2024, the fixed maximum amounts guaranteed under these letters of credit aggregated $21.0 million. At March 31, 2024, the amounts of scheduled expiration of the maximum amounts guaranteed under these letters of credit aggregate to $20.6 million in 2024, $332,000 in 2025, $0 in 2026 and $104,000 in 2027. There were no amounts outstanding under the previously mentioned letters of credit at March 31, 2024. In the normal course of business, we have surety bonds related to contracts for contracting services, reclamation obligations and insurance policies of its subsidiaries. In the event a subsidiary of Knife River does not fulfill a bonded obligation, the Company would be responsible to the surety bond company for completion of the bonded contract or obligation. A large portion of the surety bonds are expected to expire within the next 12 months; however, we will likely continue to enter into surety bonds for our subsidiaries in the future. At March 31, 2024, approximately $902.3 million of surety bonds were outstanding, which were not reflected on the Consolidated Balance Sheet.

Related party transactions

Related party transactions	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
Related party transactions	Related-party transactions Transition services agreements As part of the Separation, MDU Resources is providing transition services to Knife River and Knife River is providing transition services to MDU Resources in accordance with the Transition Services Agreement entered into on May 30, 2023. For the three months ended March 31, 2024, the Company paid $816,000 related to these activities, which were reflected in selling, general and administrative expenses on the Consolidated Statements of Operations. For the three months ended March 31, 2024, the Company received $76,000 related to these activities, which were reflected in other income on the Consolidated Statements of Operations. The majority of the transition services are expected to be completed over a period of one year, but no longer than two years after the Separation. For additional information on the presentation of related-party transactions, see Note 2.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net loss	$ (47,629)	$ (41,320)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Basis of presentation (Policies

Basis of presentation (Policies)	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation	The accompanying consolidated interim financial statements were prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Interim financial statements do not include all disclosures provided in annual financial statements and, accordingly, these financial statements should be read in conjunction with the Company's 2023 Annual Report on Form 10-K ("Annual Report"). The information is unaudited but includes adjustments that are, in the opinion of management, necessary for a fair presentation of the accompanying consolidated interim financial statements and are of a normal recurring nature. Prior to the Separation, Knife River operated as a wholly owned subsidiary of Centennial Energy Holdings, Inc., a direct wholly owned subsidiary of MDU Resources and the direct parent company of Knife River prior to the spinoff ("Centennial") and an indirect, wholly owned subsidiary of MDU Resources and not as a stand-alone company. The accompanying consolidated financial statements and footnotes for the periods prior to the Separation were prepared on a "carve-out" basis using a legal entity approach in conformity with GAAP and were derived from the consolidated financial statements of MDU Resources as if Knife River operated on a stand-alone basis during these periods. All revenues and costs, as well as assets and liabilities, directly associated with our business activities are included in the consolidated financial statements. In the periods prior to the Separation, the consolidated financial statements include expense allocations for certain functions provided by MDU Resources and Centennial, including, but not limited to certain general corporate expenses related to senior management, legal, human resources, finance and accounting, treasury, information technology, communications, procurement, tax, insurance and other shared services. These general corporate expenses are included in the Consolidated Statements of Operations within selling, general and administrative expenses and other income (expense). The amount allocated to Knife River was $4.9 million in selling, general and administrative expenses and $300,000 in other income for the three months ended March 31, 2023. These items were allocated on the basis of direct usage when identifiable, with the remainder principally allocated on the basis of percent of total capital invested or other allocation methodologies that were considered to be a reasonable reflection of the utilization of the services provided to the benefits received, including the following: number of employees paid and stated as cost per check; number of employees served; weighted factor of travel, managed units, national account spending, equipment and fleet acquisitions; purchase order dollars spent and purchase order line count; number of payments, vouchers or unclaimed property reports; labor hours; time tracked; and projected workload. The allocations may not, however, reflect the expenses we would have incurred as a stand-alone company for the periods presented. These costs also may not be indicative of the expenses that we will incur in the future or would have incurred if we had obtained these services from a third party. Prior to the Separation, Knife River participated in Centennial’s centralized cash management program, including its overall financing arrangements. Knife River also had related-party note agreements in place with Centennial for the financing of its capital needs, which are reflected as related-party notes payable on the Consolidated Balance Sheet as of March 31, 2023. Interest expense in the Consolidated Statements of Operations, for the periods prior to the Separation, reflects the allocation of interest on borrowing and funding associated with the related-party note agreements. Upon the completion of the Separation, we implemented our own financing agreements with lenders. For additional information on the Knife River's current debt financing, see Note 12. Related-party transactions between Knife River and MDU Resources or Centennial for general operating activities and intercompany debt have been included in the consolidated financial statements for periods prior to the Separation. Outstanding balances as of the periods presented were reflected on Consolidated Balance Sheets as “Due from related-party” or “Due to related-party” and “Related-party notes payable”. See Note 16 for additional information on related-party transactions. Prior to the Separation, income tax expense and tax balances in the consolidated financial statements were calculated on a separate tax return basis. The separate tax return method applies the accounting guidance for income taxes to the stand-alone financial statements as if Knife River were a separate taxpayer and a standalone enterprise. We believe the assumptions supporting the allocation and presentation of income taxes on a separate return basis are reasonable. As a stand-alone entity, we will file tax returns on our own behalf, and tax balances and effective income tax rate may differ from the amounts reported in the historical periods. Management has also evaluated the impact of events occurring after March 31, 2024, up to the date of issuance of these consolidated interim financial statements on May 7, 2024, that would require recognition or disclosure in the Consolidated Financial Statements.
Principles of consolidation	Principles of consolidation
Use of estimates	Use of estimates The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, at the date of the consolidated financial statements, as well as the reported amounts of revenues and expenses during the reporting period. Estimates are used for items such as long-lived assets and goodwill; fair values of acquired assets and liabilities under the acquisition method of accounting; aggregate reserves; property depreciable lives; tax provisions; revenue recognized using the cost-to-cost measure of progress for contracts; expected credit losses; environmental and other loss contingencies; costs on contracting services contracts; actuarially determined benefit costs; asset retirement obligations; lease classification; present value of right-of-use assets and lease liabilities; and the valuation of stock-based compensation. These estimates are based on management’s best knowledge of current events, historical experience, actions that we may undertake in the future and on various other assumptions that are believed to be reasonable under the circumstances. As additional information becomes available, or actual amounts are determinable, the recorded estimates are revised. Consequently, operating results can be affected by revisions to prior accounting estimates.
Cash, cash equivalents and restricted cash	Cash, cash equivalents and restricted cash We consider all highly liquid investments with an original maturity of three months or less, when purchased, to be cash and cash equivalents. At March 31, 2024, the $170.7 million of cash, cash equivalents and restricted cash on the Consolidated Statements of Cash Flows is comprised of $128.4 million of cash and cash equivalents and $42.3 million of restricted cash. At March 31, 2023, the Company did not have any restricted cash. At December 31, 2023, the $262.3 million of cash, cash equivalents and restricted cash on the Consolidated Statements of Cash Flows is comprised of $219.3 million of cash and cash equivalents and $43.0 million of restricted cash. Restricted cash represents deposits held by our captive insurance company that is required by state insurance regulations to remain in the captive insurance company.
Seasonality of operations	Seasonality of operations Some of our operations are seasonal and revenues from, and certain expenses for, such operations may fluctuate significantly among quarterly periods, with lower activity in the winter months and higher activity in the summer months. Accordingly, the interim results for particular segments, and for Knife River as a whole, may not be indicative of results for the full fiscal year or other future periods.
New accounting standards	The following table provides a brief description of the accounting pronouncements applicable to Knife River and the potential impact on its consolidated financial statements and/or disclosures: Standard Description Standard Effective Date Impact on financial statements/disclosures Recently issued Financial Accounting Standards Board (FASB) accounting standards updates ("ASU") not yet adopted ASU 2023-07 - Improvements to Reportable Segment Disclosures In November 2023, the FASB issued guidance on modifying the disclosure requirements to improve reportable segment disclosure requirements through enhanced disclosures about significant segment expenses. The guidance also expands the interim disclosure requirements. The guidance is to be applied on a retrospective basis to the financial statements and footnotes and early adoption is permitted. Fiscal periods beginning after December 15, 2023 and interim periods beginning after December 31, 2024 The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2024 and interim periods for fiscal year 2025. ASU 2023-09 - Improvements to Income Tax Disclosures In December 2023, the FASB issued guidance on modifying the disclosure requirements to increase transparency about income tax information through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information. The guidance is to be applied on a prospective basis to the financial statements and footnotes, however, retrospective adoption is also permitted. The guidance also permits early adoption. Fiscal periods beginning after December 15, 2024 The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2025.
Accounts receivable and allowance for doubtful accounts	Receivables consist primarily of trade and contract receivables for the sale of goods and services net of expected credit losses. A majority of our receivables are due in 30 days or less.
Accounting Standards Update and Change in Accounting Principle	The following table provides a brief description of the accounting pronouncements applicable to Knife River and the potential impact on its consolidated financial statements and/or disclosures: Standard Description Standard Effective Date Impact on financial statements/disclosures Recently issued Financial Accounting Standards Board (FASB) accounting standards updates ("ASU") not yet adopted ASU 2023-07 - Improvements to Reportable Segment Disclosures In November 2023, the FASB issued guidance on modifying the disclosure requirements to improve reportable segment disclosure requirements through enhanced disclosures about significant segment expenses. The guidance also expands the interim disclosure requirements. The guidance is to be applied on a retrospective basis to the financial statements and footnotes and early adoption is permitted. Fiscal periods beginning after December 15, 2023 and interim periods beginning after December 31, 2024 The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2024 and interim periods for fiscal year 2025. ASU 2023-09 - Improvements to Income Tax Disclosures In December 2023, the FASB issued guidance on modifying the disclosure requirements to increase transparency about income tax information through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information. The guidance is to be applied on a prospective basis to the financial statements and footnotes, however, retrospective adoption is also permitted. The guidance also permits early adoption. Fiscal periods beginning after December 15, 2024 The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2025.
Expected credit loss	The Company's expected credit losses are determined through a review using historical credit loss experience; changes in asset specific characteristics; current conditions; and reasonable and supportable future forecasts, among other specific account data, and is performed at least quarterly. We develop and document our methodology to determine our allowance for expected credit losses. Risk characteristics used by management may include customer mix, knowledge of customers and general economic conditions of the various local economies, among others. Specific account balances are written off when management determines the amounts to be uncollectible.
Earnings per share	Basic net loss per share is computed by dividing net loss by the weighted average number of shares of common stock outstanding during the applicable period. Diluted earnings per share is computed by dividing net income by the total of the weighted average number of shares of common stock outstanding during the applicable period, plus the effect of non-vested performance shares and restricted stock units.
Disaggregation of revenue	Revenue is recognized when a performance obligation is satisfied by transferring control over a product or service to a customer. Revenue includes revenue from the sales of construction materials and contracting services. Revenue is measured based on consideration specified in a contract with a customer and excludes any sales incentives and amounts collected on behalf of third parties. Knife River is considered an agent for certain taxes collected from customers. As such, we present revenues net of these taxes at the time of sale to be remitted to governmental authorities, including sales and use taxes. Revenue for construction materials is recognized at a point in time when delivery of the products has taken place. Contracting revenue is recognized over time using an input method based on the cost-to-cost measure of progress on a project.
Fair value measurements	We measure our investments in certain fixed-income and equity securities at fair value with changes in fair value recognized in income.
Business segment data	Company’s reportable segments, Pacific, Northwest, Mountain, Central and Energy Services, which are based on our method of internal reporting and management of our business. Four of the reportable segments are aligned by key geographic areas due to the production of construction materials and related contracting services and one is based on product line. Each segment is led by a segment manager who reports to the Company’s chief operating officer, who is also the Company's chief operating decision maker, along with the chief executive officer. The chief operating decision maker evaluates the performance of the segments and allocates resources to them based on earnings before interest, taxes, depreciation, depletion and amortization ("EBITDA"). In the fourth quarter of 2023, we realigned our reportable segments to better support our operational strategies. The liquid asphalt and related services portion of the Pacific segment's businesses are now reported under the Energy Services segment. In addition, the North Central and South operating regions have been aggregated into one reportable segment, Central. We also reallocated certain amounts to the operating segments that were previously reported within Corporate Services. All periods have been recast to conform with the revised presentation.
Commitments and contingencies	The Company is party to claims and lawsuits arising out of its business and that of its consolidated subsidiaries, which may include, but are not limited to, matters involving property damage, personal injury, and environmental, contractual and statutory obligations. We accrue a liability for those contingencies when the incurrence of a loss is probable and the amount can be reasonably estimated. If a range of amounts can be reasonably estimated and no amount within the range is a better estimate than any other amount, then the minimum of the range is accrued. We do not accrue liabilities when the likelihood that the liability has been incurred is probable but the amount cannot be reasonably estimated or when the liability is believed to be only reasonably possible or remote. For contingencies where an unfavorable outcome is probable or reasonably possible and which are material, we disclose the nature of the contingency and, in some circumstances, an estimate of the possible loss. Accruals are based on the best information available, but in certain situations management is unable to estimate an amount or range of a reasonably possible loss including, but not limited to when: (1) the damages are unsubstantiated or indeterminate, (2) the proceedings are in the early stages, (3) numerous parties are involved, or (4) the matter involves novel or unsettled legal theories.

Receivables and allowance for_2

Receivables and allowance for expected credit losses (Tables)	3 Months Ended
	Mar. 31, 2024
Credit Loss [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable	Receivables were as follows: March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Trade receivables $ 107,834 $ 100,487 $ 124,134 Contract receivables 50,427 52,487 112,037 Retention receivables 31,524 27,438 36,782 Receivables, gross 189,785 180,412 272,953 Less expected credit loss 6,077 5,822 6,168 Receivables, net $ 183,708 $ 174,590 $ 266,785
Accounts Receivable, Allowance for Credit Loss	Details of the Company's expected credit losses were as follows: Pacific Northwest Mountain Central Energy Services Total (In thousands) As of December 31, 2023 $ 2,053 $ 1,004 $ 2,293 $ 718 $ 100 $ 6,168 Current expected credit loss provision 177 (223) (47) 87 — (6) Less write-offs charged against the allowance (53) 133 2 3 — 85 At March 31, 2024 $ 2,283 $ 648 $ 2,244 $ 802 $ 100 $ 6,077 Pacific Northwest Mountain Central Energy Services Total (In thousands) As of December 31, 2022 $ 1,945 $ 1,253 $ 1,278 $ 901 $ 100 $ 5,477 Current expected credit loss provision 45 313 164 (90) — 432 Less write-offs charged against the allowance 1 68 18 — — 87 At March 31, 2023 $ 1,989 $ 1,498 $ 1,424 $ 811 $ 100 $ 5,822

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2024
Inventory Disclosure [Abstract]
Inventories	Inventories on the Consolidated Balance Sheets were as follows: March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Finished products $ 242,952 $ 220,234 $ 225,319 Raw materials 95,132 114,735 61,776 Supplies and parts 37,699 38,246 32,528 Total $ 375,783 $ 373,215 $ 319,623

Net loss per share (Tables)

Net loss per share (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Schedule of Weighted Average Number of Shares	Basic and diluted earnings per share are calculated as follows, based on a reconciliation of the weighted-average common shares outstanding on a basic and diluted basis: Three Months Ended March 31, 2024 2023 (In thousands, except per share amounts) Net loss $ (47,629) $ (41,320) Weighted average common shares outstanding - basic 56,590 56,566 Effect of dilutive performance shares and restricted stock units — — Weighted average common shares outstanding - diluted 56,590 56,566 Shares excluded from the calculation of diluted loss per share 179 — Net loss per share - basic $ (.84) $ (.73) Net loss per share - diluted $ (.84) $ (.73)

Accumulated other comprehensi_2

Accumulated other comprehensive loss (Tables)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The after-tax changes in the components of accumulated other comprehensive loss were as follows: Net Unrealized Postretirement Total (In thousands) As of December 31, 2023 $ — $ (11,319) $ (11,319) Amounts reclassified from accumulated other comprehensive loss — 78 78 Net current-period other comprehensive income — 78 78 At March 31, 2024 $ — $ (11,241) $ (11,241) Net Unrealized Postretirement Total (In thousands) As of December 31, 2022 $ (90) $ (12,262) $ (12,352) Amounts reclassified from accumulated other comprehensive loss 46 47 93 Net current-period other comprehensive income 46 47 93 At March 31, 2023 $ (44) $ (12,215) $ (12,259)
Reclassification out of Accumulated Other Comprehensive Income	The following amounts were reclassified out of accumulated other comprehensive loss into net loss. The amounts presented in parenthesis indicate a decrease to net loss on the Consolidated Statements of Operations. The reclassifications were as follows: Three Months Ended Location on Consolidated Statements of Operations March 31, 2024 2023 (In thousands) Reclassification adjustment for loss on derivative instruments included in net loss $ — $ (61) Interest expense — 15 Income taxes — (46) Amortization of postretirement liability losses included in net periodic benefit cost (103) (62) Other income 25 15 Income taxes (78) (47) Total reclassifications $ (78) $ (93)

Revenue from contracts with c_2

Revenue from contracts with customers (Tables)	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	Three Months Ended March 31, 2024 Pacific Northwest Mountain Central Energy Services Corporate Services and Eliminations Total (In thousands) Aggregates $ 19,549 $ 39,398 $ 9,455 $ 15,871 $ — $ — $ 84,273 Ready-mix concrete 31,220 31,776 13,835 23,024 — — 99,855 Asphalt 2,347 8,237 830 5,059 — — 16,473 Liquid asphalt — — — — 11,035 — 11,035 Other 25,330 3,574 5 1,898 3,062 5,142 39,011 Contracting services public-sector 5,475 36,044 25,859 21,033 — — 88,411 Contracting services private-sector 8,074 15,031 13,803 176 — — 37,084 Internal sales (13,608) (14,908) (3,962) (6,097) (2,981) (4,996) (46,552) Revenues from contracts with customers $ 78,387 $ 119,152 $ 59,825 $ 60,964 $ 11,116 $ 146 $ 329,590 Three Months Ended March 31, 2023 Pacific Northwest Mountain Central Energy Services Corporate Services and Eliminations Total (In thousands) Aggregates $ 18,697 $ 42,573 $ 9,667 $ 12,584 $ — $ — $ 83,521 Ready-mix concrete 26,144 33,905 14,370 22,350 — — 96,769 Asphalt 1,316 6,927 810 4,566 — — 13,619 Liquid asphalt — — — — 8,287 — 8,287 Other 23,420 2,682 2 1,585 2,191 426 30,306 Contracting services public-sector 3,971 17,003 28,238 22,860 — — 72,072 Contracting services private-sector 2,899 25,761 13,445 806 — — 42,911 Internal sales (10,804) (12,932) (5,914) (7,131) (2,222) (582) (39,585) Revenues from contracts with customers $ 65,643 $ 115,919 $ 60,618 $ 57,620 $ 8,256 $ (156) $ 307,900

Uncompleted contracts (Tables)

Uncompleted contracts (Tables)	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Contract with Customer, Contract Asset, Contract Liability, and Receivable	The changes in contract assets and liabilities were as follows: March 31, 2024 December 31, 2023 Change Location on Consolidated Balance Sheets (In thousands) Contract assets $ 33,559 $ 27,293 $ 6,266 Costs and estimated earnings in excess of billings on uncompleted contracts Contract liabilities (50,844) (51,376) 532 Billings in excess of costs and estimated earnings on uncompleted contracts Net contract liabilities $ (17,285) $ (24,083) $ 6,798 March 31, 2023 December 31, 2022 Change Location on Consolidated Balance Sheets (In thousands) Contract assets $ 30,974 $ 31,145 $ (171) Costs and estimated earnings in excess of billings on uncompleted contracts Contract liabilities (37,375) (39,843) 2,468 Billings in excess of costs and estimated earnings on uncompleted contracts Net contract liabilities $ (6,401) $ (8,698) $ 2,297

Goodwill and other intangible_2

Goodwill and other intangible assets (Tables)	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in the carrying amount of goodwill were as follows: Balance at January 1, 2024 Goodwill Acquired During the Year Measurement Period Adjustments Reallocation of Goodwill Balance at March 31, 2024 (In thousands) Pacific $ 32,621 $ — $ — $ — $ 32,621 Northwest 90,978 — — — 90,978 Mountain 26,816 — — — 26,816 North Central 75,879 — — — 75,879 South 38,708 — — — 38,708 Energy Services 9,476 — — — 9,476 Total $ 274,478 $ — $ — $ — $ 274,478 Balance at January 1, 2023 Goodwill Acquired During the Year Measurement Period Adjustments Reallocation of Goodwill Balance at March 31, 2023 (In thousands) Pacific $ 38,339 $ — $ — $ — $ 38,339 Northwest 90,978 — — — 90,978 Mountain 26,816 — — — 26,816 North Central 75,879 — — — 75,879 South 38,708 — — — 38,708 Energy Services 3,820 — — — 3,820 Total $ 274,540 $ — $ — $ — $ 274,540 Balance at January 1, 2023 Goodwill Acquired During the Year Measurement Period Adjustments Reallocation of Goodwill Balance at December 31, 2023 (In thousands) Pacific $ 38,339 $ — $ (62) $ (5,656) $ 32,621 Northwest 90,978 — — — 90,978 Mountain 26,816 — — — 26,816 North Central 75,879 — — — 75,879 South 38,708 — — — 38,708 Energy Services 3,820 — — 5,656 9,476 Total $ 274,540 $ — $ (62) $ — $ 274,478
Schedule of Finite-Lived Intangible Assets	Other amortizable intangible assets were as follows: March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Customer relationships $ 18,540 $ 18,540 $ 18,540 Less accumulated amortization 9,535 7,801 9,102 9,005 10,739 9,438 Noncompete agreements 3,820 4,039 4,039 Less accumulated amortization 3,315 3,113 3,473 505 926 566 Other 1,796 2,479 2,479 Less accumulated amortization 1,029 1,381 1,662 767 1,098 817 Total $ 10,277 $ 12,763 $ 10,821
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	Estimated amortization expense for identifiable intangible assets as of March 31, 2024, was: Remainder of 2024 2025 2026 2027 2028 Thereafter (In thousands) Amortization expense $ 1,683 $ 1,918 $ 1,738 $ 1,716 $ 1,672 $ 1,550

Fair value measurements (Tables

Fair value measurements (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The Company's assets measured at fair value on a recurring basis were as follows: Fair Value Measurements at March 31, 2024, Using Quoted Prices in Significant Significant Balance at March 31, 2024 (In thousands) Assets: Money market funds $ — $ 3,845 $ — $ 3,845 Insurance contracts* — 27,059 — 27,059 Total assets measured at fair value $ — $ 30,904 $ — $ 30,904 * The insurance contracts invest approximately 36 percent in fixed-income investments, 22 percent in common stock of large-cap companies, 16 percent in cash equivalents, 10 percent in common stock of mid-cap companies, 8 percent target date investments, 5 percent in common stock of small-cap companies, 1 percent in international investments, 1 percent in real estate investments and 1 percent in high yield investments. Fair Value Measurements at March 31, 2023, Using Quoted Prices in Significant Significant Balance at March 31, 2023 (In thousands) Assets: Money market funds $ — $ 2,472 $ — $ 2,472 Insurance contracts* — 22,438 — 22,438 Total assets measured at fair value $ — $ 24,910 $ — $ 24,910 * The insurance contracts invest approximately 61 percent in fixed-income investments, 15 percent in common stock of large-cap companies, 8 percent in common stock of mid-cap companies, 7 percent target date investments, 6 percent in common stock of small-cap companies, 2 percent in cash equivalents, and 1 percent in international investments. Fair Value Measurements at December 31, 2023, Using Quoted Prices in Significant Significant Balance at December 31, 2023 (In thousands) Assets: Money market funds $ — $ 3,241 $ — $ 3,241 Insurance contracts* — 24,896 — 24,896 Total assets measured at fair value $ — $ 28,137 $ — $ 28,137 * The insurance contracts invest approximately 40 percent in fixed-income investments, 19 percent in common stock of large-cap companies, 18 percent in cash equivalents, 8 percent in target date investments, 8 percent in common stock of mid-cap companies, 6 percent in common stock of small-cap companies and 1 percent in international investments.
Fair Value, by Balance Sheet Grouping	The estimated fair value of the Company's Level 2 long-term debt was as follows: March 31, 2024 December 31, 2023 (In thousands) Carrying amount $ 695,247 $ 696,985 Fair value $ 715,962 $ 725,086

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of Long-Term Debt Instruments	Long-term debt outstanding was as follows: Weighted Average Interest Rate at March 31, 2024 March 31, 2024 December 31, 2023 (In thousands) Term loan agreement due on May 31, 2028 7.19 % $ 269,844 $ 271,562 Senior notes due on May 1, 2031 7.75 % 425,000 425,000 Other notes due on January 1, 2061 — % 403 423 Less unamortized debt issuance costs 14,636 15,326 Total long-term debt 680,611 681,659 Less current maturities 7,072 7,082 Net long-term debt $ 673,539 $ 674,577
Schedule of Maturities of Long-Term Debt	Long-term debt maturities, which excludes unamortized debt issuance costs, at March 31, 2024, were as follows: Remainder of 2024 2025 2026 2027 2028 Thereafter (In thousands) Long-term debt maturities $ 5,353 $ 10,518 $ 13,750 $ 17,188 $ 223,438 $ 425,000

Cash flow information (Tables)

Cash flow information (Tables)	3 Months Ended
	Mar. 31, 2024
Supplemental Cash Flow Information [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	Cash expenditures for interest and income taxes were as follows: Three Months Ended March 31, 2024 2023 (In thousands) Interest paid, net $ 5,764 $ 7,081 Income taxes paid, net $ — $ 150 Noncash investing and financing transactions were as follows: Three Months Ended March 31, 2024 2023 (In thousands) Right-of-use assets obtained in exchange for new operating lease liabilities $ 4,802 $ 1,894 Property, plant and equipment additions in accounts payable $ 6,046 $ 2,607

Business segment data (Tables)

Business segment data (Tables)	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Information on the Company's segments was as follows: Three Months Ended March 31, 2024 2023 (In thousands) External operating revenues: Pacific $ 78,387 $ 65,643 Northwest 119,152 115,919 Mountain 59,825 60,618 Central 60,964 57,620 Energy Services 11,116 8,256 Corporate Services and Eliminations 146 (156) Total external operating revenues $ 329,590 $ 307,900 Intersegment operating revenues: Pacific $ 13,608 $ 10,804 Northwest 14,908 12,932 Mountain 3,962 5,914 Central 6,097 7,131 Energy Services 2,981 2,222 Corporate Services and Eliminations 4,996 582 Total intersegment operating revenues $ 46,552 $ 39,585 EBITDA: Pacific $ (743) $ 148 Northwest 20,154 13,996 Mountain (6,064) (3,753) Central (18,722) (16,899) Energy Services (2,483) (2,977) Corporate Services and Eliminations (12,738) (4,623) Total segment EBITDA $ (20,596) $ (14,108)
Reconciliation of Revenue from Segments to Consolidated	A reconciliation of consolidated operating revenues to reportable segment operating revenues is as follows: Three Months Ended March 31, 2024 2023 (In thousands) Consolidated operating revenues $ 329,590 $ 307,900 Plus: Intersegment operating revenues 46,552 39,585 Less: Corporate Services revenue 5,142 426 Total reportable segment operating revenues $ 371,000 $ 347,059
Segment, Reconciliation of Other Items from Segments to Consolidated	A reconciliation of consolidated loss before income taxes to reportable segment EBITDA is as follows: Three Months Ended March 31, 2024 2023 (In thousands) Total consolidated loss before income taxes $ (63,955) $ (53,232) Plus: Depreciation, depletion and amortization 32,212 29,629 Interest expense, net* 11,147 9,495 Less: Corporate Services EBITDA (12,738) (4,623) Total EBITDA for reportable segments $ (7,858) $ (9,485) * Interest, net is interest expense net of interest income.

Background (Details)

Background (Details)	1 Months Ended	3 Months Ended
	Nov. 30, 2023 shares	Mar. 31, 2024 state reportableSegment $ / shares	Dec. 31, 2023 $ / shares	May 31, 2023 $ / shares	Mar. 31, 2023 $ / shares
Organization [Line Items]
Number of states in which entity operates | state		14
Number of reportable segments | reportableSegment		5
Separation transaction, percent of outstanding shares distributed				90%
Common stock, par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01	$ 0.01	$ 10
Separation transaction, distribution ratio				0.25
Separation transaction, outstanding shares distributed (in shares) | shares	5,656,621
Knife River
Organization [Line Items]
Subsidiary, ownership percentage, noncontrolling owner				10%

Basis of presentation (Details)

Basis of presentation (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Line Items]
Cash, cash equivalents and restricted cash	$ 7,218,000	$ 170,658,000	$ 262,320,000	$ 10,090,000
Cash and cash equivalents		128,400,000	219,300,000
Restricted cash	0	$ 42,300,000	$ 43,000,000
Related Party | Selling, General and Administrative Expenses
Accounting Policies [Line Items]
Costs and expenses, related party	4,900,000
Related Party | Other Nonoperating Income (Expense)
Accounting Policies [Line Items]
Costs and expenses, related party	$ 300,000

Receivables and allowance for_3

Receivables and allowance for expected credit losses - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Credit Loss [Abstract]
Accounts receivable, noncurrent, 90 days or more past due, still accruing	$ 12.6	$ 16.7	$ 13.7

Receivables and allowance for_4

Receivables and allowance for expected credit losses - Summary of Receivables (Details) - Trade Accounts Receivable - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade receivables	$ 107,834	$ 124,134	$ 100,487
Contract receivables	50,427	112,037	52,487
Retention receivables	31,524	36,782	27,438
Receivables, gross	189,785	272,953	180,412
Less expected credit loss	6,077	6,168	5,822	$ 5,477
Receivables, net	$ 183,708	$ 266,785	$ 174,590

Receivables and allowance for_5

Receivables and allowance for expected credit losses - Details of Expected Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Provision for credit losses	$ (6)	$ 428
Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	6,168	5,477
Provision for credit losses	(6)	432
Less write-offs charged against the allowance	85	87
Ending balance	6,077	5,822
Pacific | Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,053	1,945
Provision for credit losses	177	45
Less write-offs charged against the allowance	(53)	1
Ending balance	2,283	1,989
Northwest | Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,004	1,253
Provision for credit losses	(223)	313
Less write-offs charged against the allowance	133	68
Ending balance	648	1,498
Mountain | Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,293	1,278
Provision for credit losses	(47)	164
Less write-offs charged against the allowance	2	18
Ending balance	2,244	1,424
Central | Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	718	901
Provision for credit losses	87	(90)
Less write-offs charged against the allowance	3	0
Ending balance	802	811
Energy Services | Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	100	100
Provision for credit losses	0	0
Less write-offs charged against the allowance	0	0
Ending balance	$ 100	$ 100

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Inventory Disclosure [Abstract]
Finished products	$ 242,952	$ 225,319	$ 220,234
Raw materials	95,132	61,776	114,735
Supplies and parts	37,699	32,528	38,246
Total	$ 375,783	$ 319,623	$ 373,215

Net loss per share - Narrative

Net loss per share - Narrative (Details) - shares	Mar. 31, 2024	Dec. 31, 2023
Earnings Per Share [Abstract]
Common stock, issued (in shares)	57,040,840	57,009,542
Treasury stock held at cost (in shares)	431,136	431,136

Net loss per share - Reconcilia

Net loss per share - Reconciliation of the Weighted-Average Common Shares Outstanding on a Basic and Diluted Basis (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Net loss	$ (47,629)	$ (41,320)
Weighted average common shares outstanding - basic (in shares)	56,590	56,566
Effect of dilutive restricted stock units (in shares)	0	0
Weighted average common shares outstanding - diluted (in shares)	56,590	56,566
Shares excluded from the calculation of diluted earnings per share (in shares)	179	0
Basic (in dollars per share)	$ (0.84)	$ (0.73)
Diluted (in dollars per share)	$ (0.84)	$ (0.73)

Accumulated other comprehensi_3

Accumulated other comprehensive loss - After-Tax Changes in the Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accumulated other comprehensive loss [Roll Forward]
Beginning balance	$ 1,266,012	$ 1,028,589
Net current-period other comprehensive income	78	93
Ending balance	1,218,627	974,769
Net Unrealized Loss on Derivative Instruments Qualifying as Hedges
Accumulated other comprehensive loss [Roll Forward]
Beginning balance	0	(90)
Amounts reclassified from accumulated other comprehensive loss	0	46
Net current-period other comprehensive income	0	46
Ending balance	0	(44)
Postretirement Liability Adjustment
Accumulated other comprehensive loss [Roll Forward]
Beginning balance	(11,319)	(12,262)
Amounts reclassified from accumulated other comprehensive loss	78	47
Net current-period other comprehensive income	78	47
Ending balance	(11,241)	(12,215)
Total Accumulated Other Comprehensive Loss
Accumulated other comprehensive loss [Roll Forward]
Beginning balance	(11,319)	(12,352)
Amounts reclassified from accumulated other comprehensive loss	78	93
Net current-period other comprehensive income	78	93
Ending balance	$ (11,241)	$ (12,259)

Accumulated other comprehensi_4

Accumulated other comprehensive loss - Reclassification out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reclassification adjustment out of accumulated other comprehensive loss [Line Items]
Interest expense	$ (13,976)	$ (9,495)
Income tax benefit	16,326	11,912
Other income	3,748	826
Net loss	(47,629)	(41,320)
Reclassification out of accumulated other comprehensive loss
Reclassification adjustment out of accumulated other comprehensive loss [Line Items]
Net loss	(78)	(93)
Net Unrealized Loss on Derivative Instruments Qualifying as Hedges | Reclassification out of accumulated other comprehensive loss | Interest rate contract
Reclassification adjustment out of accumulated other comprehensive loss [Line Items]
Interest expense	0	(61)
Income tax benefit	0	15
Net loss	0	(46)
Amortization of postretirement liability losses included in net periodic benefit cost | Reclassification out of accumulated other comprehensive loss
Reclassification adjustment out of accumulated other comprehensive loss [Line Items]
Income tax benefit	25	15
Other income	(103)	(62)
Net loss	$ (78)	$ (47)

Revenue from contracts with c_3

Revenue from contracts with customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 329,590	$ 307,900
Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenue	(46,552)	(39,585)
Aggregates
Disaggregation of Revenue [Line Items]
Revenue	84,273	83,521
Ready-mix concrete
Disaggregation of Revenue [Line Items]
Revenue	99,855	96,769
Asphalt
Disaggregation of Revenue [Line Items]
Revenue	16,473	13,619
Other
Disaggregation of Revenue [Line Items]
Revenue	39,011	30,306
Contracting services public-sector
Disaggregation of Revenue [Line Items]
Revenue	88,411	72,072
Contracting services private-sector
Disaggregation of Revenue [Line Items]
Revenue	37,084	42,911
Liquid Asphalt
Disaggregation of Revenue [Line Items]
Revenue	11,035	8,287
Pacific | Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenue	(13,608)	(10,804)
Pacific | Aggregates
Disaggregation of Revenue [Line Items]
Revenue	19,549	18,697
Pacific | Ready-mix concrete
Disaggregation of Revenue [Line Items]
Revenue	31,220	26,144
Pacific | Asphalt
Disaggregation of Revenue [Line Items]
Revenue	2,347	1,316
Pacific | Other
Disaggregation of Revenue [Line Items]
Revenue	25,330	23,420
Pacific | Contracting services public-sector
Disaggregation of Revenue [Line Items]
Revenue	5,475	3,971
Pacific | Contracting services private-sector
Disaggregation of Revenue [Line Items]
Revenue	8,074	2,899
Pacific | Liquid Asphalt
Disaggregation of Revenue [Line Items]
Revenue	0	0
Northwest | Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenue	(14,908)	(12,932)
Northwest | Aggregates
Disaggregation of Revenue [Line Items]
Revenue	39,398	42,573
Northwest | Ready-mix concrete
Disaggregation of Revenue [Line Items]
Revenue	31,776	33,905
Northwest | Asphalt
Disaggregation of Revenue [Line Items]
Revenue	8,237	6,927
Northwest | Other
Disaggregation of Revenue [Line Items]
Revenue	3,574	2,682
Northwest | Contracting services public-sector
Disaggregation of Revenue [Line Items]
Revenue	36,044	17,003
Northwest | Contracting services private-sector
Disaggregation of Revenue [Line Items]
Revenue	15,031	25,761
Northwest | Liquid Asphalt
Disaggregation of Revenue [Line Items]
Revenue	0	0
Mountain | Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenue	(3,962)	(5,914)
Mountain | Aggregates
Disaggregation of Revenue [Line Items]
Revenue	9,455	9,667
Mountain | Ready-mix concrete
Disaggregation of Revenue [Line Items]
Revenue	13,835	14,370
Mountain | Asphalt
Disaggregation of Revenue [Line Items]
Revenue	830	810
Mountain | Other
Disaggregation of Revenue [Line Items]
Revenue	5	2
Mountain | Contracting services public-sector
Disaggregation of Revenue [Line Items]
Revenue	25,859	28,238
Mountain | Contracting services private-sector
Disaggregation of Revenue [Line Items]
Revenue	13,803	13,445
Mountain | Liquid Asphalt
Disaggregation of Revenue [Line Items]
Revenue	0	0
Central | Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenue	(6,097)	(7,131)
Central | Aggregates
Disaggregation of Revenue [Line Items]
Revenue	15,871	12,584
Central | Ready-mix concrete
Disaggregation of Revenue [Line Items]
Revenue	23,024	22,350
Central | Asphalt
Disaggregation of Revenue [Line Items]
Revenue	5,059	4,566
Central | Other
Disaggregation of Revenue [Line Items]
Revenue	1,898	1,585
Central | Contracting services public-sector
Disaggregation of Revenue [Line Items]
Revenue	21,033	22,860
Central | Contracting services private-sector
Disaggregation of Revenue [Line Items]
Revenue	176	806
Central | Liquid Asphalt
Disaggregation of Revenue [Line Items]
Revenue	0	0
Corporate Services and Eliminations | Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenue	(4,996)	(582)
Corporate Services and Eliminations | Aggregates
Disaggregation of Revenue [Line Items]
Revenue	0	0
Corporate Services and Eliminations | Ready-mix concrete
Disaggregation of Revenue [Line Items]
Revenue	0	0
Corporate Services and Eliminations | Asphalt
Disaggregation of Revenue [Line Items]
Revenue	0	0
Corporate Services and Eliminations | Other
Disaggregation of Revenue [Line Items]
Revenue	5,142	426
Corporate Services and Eliminations | Contracting services public-sector
Disaggregation of Revenue [Line Items]
Revenue	0	0
Corporate Services and Eliminations | Contracting services private-sector
Disaggregation of Revenue [Line Items]
Revenue	0	0
Corporate Services and Eliminations | Liquid Asphalt
Disaggregation of Revenue [Line Items]
Revenue	0	0
Energy Services | Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenue	(2,981)	(2,222)
Energy Services | Aggregates
Disaggregation of Revenue [Line Items]
Revenue	0	0
Energy Services | Ready-mix concrete
Disaggregation of Revenue [Line Items]
Revenue	0	0
Energy Services | Asphalt
Disaggregation of Revenue [Line Items]
Revenue	0	0
Energy Services | Other
Disaggregation of Revenue [Line Items]
Revenue	3,062	2,191
Energy Services | Contracting services public-sector
Disaggregation of Revenue [Line Items]
Revenue	0	0
Energy Services | Contracting services private-sector
Disaggregation of Revenue [Line Items]
Revenue	0	0
Energy Services | Liquid Asphalt
Disaggregation of Revenue [Line Items]
Revenue	$ 11,035	$ 8,287

Uncompleted contracts - Changes

Uncompleted contracts - Changes in Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Contract assets	$ 33,559	$ 30,974	$ 27,293	$ 31,145
Change in contract assets	6,266	(171)
Billings in excess of costs and estimated earnings on uncompleted contracts	(50,844)	(37,375)	(51,376)	(39,843)
Change in contract liabilities	532	2,468
Net contract liabilities	(17,285)	(6,401)	$ (24,083)	$ (8,698)
Change in net contract assets (liabilities)	$ 6,798	$ 2,297

Uncompleted contracts - Narrati

Uncompleted contracts - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Amounts included in contract liability at the beginning of the period	$ 30.5	$ 20.3
Contract with customer, performance obligation satisfied in previous period	9.2	$ 3.6
Remaining performance obligations	959.5
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 891
Remaining performance obligations, expected timing	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 59.2
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-04-01 | Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations, expected timing	13 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-04-01 | Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations, expected timing	24 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 9.3
Remaining performance obligations, expected timing	25 months

Goodwill and other intangible_3

Goodwill and other intangible assets - Goodwill Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Goodwill [Roll Forward]
Balance at January 1, 2024	$ 274,478	$ 274,540	$ 274,540
Goodwill Acquired During the Year	0	0	0
Measurement Period Adjustments	0	0	(62)
Reallocation of Goodwill	0	0	0
Balance at March 31, 2024	274,478	274,540	274,478
Pacific
Goodwill [Roll Forward]
Balance at January 1, 2024	32,621	38,339	38,339
Goodwill Acquired During the Year	0	0	0
Measurement Period Adjustments	0	0	(62)
Reallocation of Goodwill	0	0	(5,656)
Balance at March 31, 2024	32,621	38,339	32,621
Northwest
Goodwill [Roll Forward]
Balance at January 1, 2024	90,978	90,978	90,978
Goodwill Acquired During the Year	0	0	0
Measurement Period Adjustments	0	0	0
Reallocation of Goodwill	0	0	0
Balance at March 31, 2024	90,978	90,978	90,978
Mountain
Goodwill [Roll Forward]
Balance at January 1, 2024	26,816	26,816	26,816
Goodwill Acquired During the Year	0	0	0
Measurement Period Adjustments	0	0	0
Reallocation of Goodwill	0	0	0
Balance at March 31, 2024	26,816	26,816	26,816
Central
Goodwill [Roll Forward]
Balance at January 1, 2024	75,879	75,879	75,879
Goodwill Acquired During the Year	0	0	0
Measurement Period Adjustments	0	0	0
Reallocation of Goodwill	0	0	0
Balance at March 31, 2024	75,879	75,879	75,879
South
Goodwill [Roll Forward]
Balance at January 1, 2024	38,708	38,708	38,708
Goodwill Acquired During the Year	0	0	0
Measurement Period Adjustments	0	0	0
Reallocation of Goodwill	0	0	0
Balance at March 31, 2024	38,708	38,708	38,708
Energy Services
Goodwill [Roll Forward]
Balance at January 1, 2024	9,476	3,820	3,820
Goodwill Acquired During the Year	0	0	0
Measurement Period Adjustments	0	0	0
Reallocation of Goodwill	0	0	5,656
Balance at March 31, 2024	$ 9,476	$ 3,820	$ 9,476

Goodwill and other intangible_4

Goodwill and other intangible assets - Other Amortizable Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	$ 10,277	$ 10,821	$ 12,763
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	18,540	18,540	18,540
Less accumulated amortization	9,535	9,102	7,801
Intangible assets, net (excluding goodwill)	9,005	9,438	10,739
Noncompete agreements
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	3,820	4,039	4,039
Less accumulated amortization	3,315	3,473	3,113
Intangible assets, net (excluding goodwill)	505	566	926
Other
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	1,796	2,479	2,479
Less accumulated amortization	1,029	1,662	1,381
Intangible assets, net (excluding goodwill)	$ 767	$ 817	$ 1,098

Goodwill and other intangible_5

Goodwill and other intangible assets - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 545	$ 667

Goodwill and other intangible_6

Goodwill and other intangible assets - Schedule of Future Amortization Expense (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of 2024	$ 1,683
2025	1,918
2026	1,738
2027	1,716
2028	1,672
Thereafter	$ 1,550

Fair value measurements - Narra

Fair value measurements - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Investments used to satisfy nonqualified benefit plans obligations	$ 27,100	$ 22,400	$ 24,900
Net unrealized gain (loss) on investments used to satisfy obligations under nonqualified benefit plans	$ 1,200	$ 827

Fair value measurements - Asset

Fair value measurements - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Concentration risks, percentage [Abstract]
Percentage in fixed-income and other investments	36%	40%	61%
Percentage investment in cash and cash equivalents	16%	18%	2%
Percentage investment in common stock of large-cap companies	22%	19%	15%
Percentage investment in common stock of mid-cap companies	10%	8%	8%
Percentage investment in target date investments	8%	8%	7%
Percentage investment in real estate investments	1%
Percentage investment in high yield investments	1%
Percentage investment in common stock of small-cap companies	5%	6%	6%
Percentage investment in international investments	1%	1%	1%
Carrying amount
Concentration risks, percentage [Abstract]
Long-term debt, fair value	$ 695,247	$ 696,985
Fair value
Concentration risks, percentage [Abstract]
Long-term debt, fair value	715,962	725,086
Fair value, measurements, recurring
Fair value measurements [Line Items]
Total assets measured at fair value	30,904	28,137	$ 24,910
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value, measurements, recurring
Fair value measurements [Line Items]
Total assets measured at fair value	0	0	0
Significant Other Observable Inputs (Level 2) | Fair value, measurements, recurring
Fair value measurements [Line Items]
Total assets measured at fair value	30,904	28,137	24,910
Significant Unobservable Inputs (Level 3) | Fair value, measurements, recurring
Fair value measurements [Line Items]
Total assets measured at fair value	0	0	0
Money market funds | Fair value, measurements, recurring
Fair value measurements [Line Items]
Total assets measured at fair value	3,845	3,241	2,472
Money market funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value, measurements, recurring
Fair value measurements [Line Items]
Total assets measured at fair value	0	0	0
Money market funds | Significant Other Observable Inputs (Level 2) | Fair value, measurements, recurring
Fair value measurements [Line Items]
Total assets measured at fair value	3,845	3,241	2,472
Money market funds | Significant Unobservable Inputs (Level 3) | Fair value, measurements, recurring
Fair value measurements [Line Items]
Total assets measured at fair value	0	0	0
Insurance contracts | Fair value, measurements, recurring
Fair value measurements [Line Items]
Total assets measured at fair value	27,059	24,896	22,438
Insurance contracts | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair value, measurements, recurring
Fair value measurements [Line Items]
Total assets measured at fair value	0	0	0
Insurance contracts | Significant Other Observable Inputs (Level 2) | Fair value, measurements, recurring
Fair value measurements [Line Items]
Total assets measured at fair value	27,059	24,896	22,438
Insurance contracts | Significant Unobservable Inputs (Level 3) | Fair value, measurements, recurring
Fair value measurements [Line Items]
Total assets measured at fair value	$ 0	$ 0	$ 0

Fair value measurements - Fair

Fair value measurements - Fair Value of Long-Term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Carrying amount
Fair value, balance sheet grouping [Line Items]
Long-term debt, fair value	$ 695,247	$ 696,985
Fair value
Fair value, balance sheet grouping [Line Items]
Long-term debt, fair value	$ 715,962	$ 725,086

Debt - Long-Term Debt Outstandi

Debt - Long-Term Debt Outstanding (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Long-term debt outstanding [Line Items]
Less unamortized debt issuance costs	$ 14,636	$ 15,326
Total long-term debt	680,611	681,659
Long-term debt - current portion	7,072	7,082	$ 211
Net long-term debt	$ 673,539	674,577	$ 359
Senior Notes
Long-term debt outstanding [Line Items]
Weighted Average Interest Rate at March 31, 2024	7.75%
Long-term debt, gross	$ 425,000	425,000
Loans Payable
Long-term debt outstanding [Line Items]
Weighted Average Interest Rate at March 31, 2024	7.19%
Long-term debt, gross	$ 269,844	271,562
Other Notes
Long-term debt outstanding [Line Items]
Weighted Average Interest Rate at March 31, 2024	0%
Long-term debt, gross	$ 403	$ 423

Debt - Schedule of Debt Maturit

Debt - Schedule of Debt Maturities (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Debt Disclosure [Abstract]
Remainder of 2024	$ 5,353
2025	10,518
2026	13,750
2027	17,188
2028	223,438
Thereafter	$ 425,000

Cash flow information (Details)

Cash flow information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Supplemental Cash Flow Information [Abstract]
Interest paid, net	$ 5,764	$ 7,081
Income taxes paid, net	0	150
Right-of-use assets obtained in exchange for new operating lease liabilities	4,802	1,894
Property, plant and equipment additions in accounts payable	$ 6,046	$ 2,607

Business segment data - Narrati

Business segment data - Narrative (Details)	Mar. 31, 2024 state
Business Combination and Asset Acquisition [Abstract]
Number of states in which entity operates	14

Business segment data - Informa

Business segment data - Information on Segment Data (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Revenues	$ 329,590	$ 307,900
EBITDA:	(20,596)	(14,108)
Corporate, Non-Segment & Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	146	(156)
EBITDA:	(12,738)	(4,623)
Operating Segments
Segment Reporting Information [Line Items]
Revenues	371,000	347,059
EBITDA:	(7,858)	(9,485)
Operating Segments | Pacific
Segment Reporting Information [Line Items]
Revenues	78,387	65,643
EBITDA:	(743)	148
Operating Segments | Northwest
Segment Reporting Information [Line Items]
Revenues	119,152	115,919
EBITDA:	20,154	13,996
Operating Segments | Mountain
Segment Reporting Information [Line Items]
Revenues	59,825	60,618
EBITDA:	(6,064)	(3,753)
Operating Segments | Central
Segment Reporting Information [Line Items]
Revenues	60,964	57,620
EBITDA:	(18,722)	(16,899)
Operating Segments | Energy Services
Segment Reporting Information [Line Items]
Revenues	11,116	8,256
EBITDA:	(2,483)	(2,977)
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Revenues	5,142	426
EBITDA:	(12,738)	(4,623)
Intersegment eliminations
Segment Reporting Information [Line Items]
Revenues	(46,552)	(39,585)
Intersegment eliminations | Pacific
Segment Reporting Information [Line Items]
Revenues	(13,608)	(10,804)
Intersegment eliminations | Northwest
Segment Reporting Information [Line Items]
Revenues	(14,908)	(12,932)
Intersegment eliminations | Mountain
Segment Reporting Information [Line Items]
Revenues	(3,962)	(5,914)
Intersegment eliminations | Central
Segment Reporting Information [Line Items]
Revenues	(6,097)	(7,131)
Intersegment eliminations | Energy Services
Segment Reporting Information [Line Items]
Revenues	(2,981)	(2,222)
Intersegment eliminations | Corporate Services and Eliminations
Segment Reporting Information [Line Items]
Revenues	$ (4,996)	$ (582)

Business segment data - Operati

Business segment data - Operating Revenues Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ (329,590)	$ (307,900)
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	(371,000)	(347,059)
Corporate, Non-Segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	(5,142)	(426)
Total intersegment operating revenues
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 46,552	$ 39,585

Business segment data - EBITDA

Business segment data - EBITDA Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment, Reconciliation of Other Items from Segments to Consolidated [Line Items]
EBITDA:	$ (20,596)	$ (14,108)
Depreciation, depletion and amortization	32,212	29,629
Interest expense, net	11,147	9,495
Total consolidated loss before income taxes	(63,955)	(53,232)
Operating Segments
Segment, Reconciliation of Other Items from Segments to Consolidated [Line Items]
EBITDA:	(7,858)	(9,485)
Corporate, Non-Segment
Segment, Reconciliation of Other Items from Segments to Consolidated [Line Items]
EBITDA:	$ (12,738)	$ (4,623)

Commitments and contingencies (

Commitments and contingencies (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Loss Contingencies [Line Items]
Potential liabilities related to litigation and environmental matters	$ 1,200,000	$ 873,000	$ 2,000,000
Insurance receivables	400,000	$ 42,000	$ 1,300,000
Guarantor obligations, maximum exposure, undiscounted	11,500,000
Amount outstanding under guarantees that is reflected on balance sheet	0
Letters of credit set to expire current year	20,600,000
Letters of credit set to expire in next fiscal year	332,000
Letters of credit set to expire, year three	0
Letters of credit set to expire, year four	104,000
Outstanding letters of credit	$ 0
Surety bond expiration period	12 months
Amount of surety bonds outstanding	$ 902,300,000
Letter of Credit
Loss Contingencies [Line Items]
Line of credit facility, maximum borrowing capacity	$ 21,000,000

Related party transactions (Det

Related party transactions (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Related Party Transaction [Line Items]
Selling, general and administrative expenses	$ 60,221	$ 48,658
Other income	$ 3,748	$ 826
Minimum
Related Party Transaction [Line Items]
Transition services, period	1 year
Maximum
Related Party Transaction [Line Items]
Transition services, period	2 years
Related Party
Related Party Transaction [Line Items]
Selling, general and administrative expenses	$ 816
Other income	$ 76