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Cover Page - USD ($)
12 Months Ended
Dec. 31, 2023
Feb. 15, 2024
Jun. 30, 2023
Cover [Abstract]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2023    
Current Fiscal Year End Date --12-31    
Document Transition Report false    
Entity File Number 1-03480    
Entity Registrant Name MDU RESOURCES GROUP INC    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 30-1133956    
Entity Address, Address Line One 1200 West Century Avenue    
Entity Address, Address Line Two P.O. Box 5650    
Entity Address, City or Town Bismarck    
Entity Address, State or Province ND    
Entity Address, Postal Zip Code 58506-5650    
City Area Code 701    
Local Phone Number 530-1000    
Title of 12(b) Security Common Stock, par value $1.00 per share    
Trading Symbol MDU    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag true    
Document Financial Statement Error Correction [Flag] false    
Entity Shell Company false    
Entity Public Float     $ 4,264,003,259
Entity Common Stock, Shares Outstanding   203,689,090  
Documents Incorporated by Reference
Relevant portions of the registrant's 2024 Proxy Statement, to be filed no later than 120 days from December 31, 2023, are incorporated by reference in Part III, Items 10, 11, 12, 13 and 14 of this Report.
   
Entity Central Index Key 0000067716    
Document Fiscal Year Focus 2023    
Document Fiscal Period Focus FY    
Amendment Flag false