| Cover page | Aug. 08, 2023 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Aug. 08, 2023 |
| Entity Registrant Name | Knife River Corporation |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 1-41642 |
| 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.01 par value |
| Trading Symbol | KNF |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001955520 |
| Amendment Flag | false |
