v3.26.1
Related-Party and Exempt Party-In-Interest Transactions (Details) - EBP 001 - USD ($)
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Sep. 03, 2024
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments $ 212,248,664 $ 177,574,238  
Total investments 221,342,104    
Notes receivable from participants 3,646,998 3,265,295 $ 3,200,000
Investment, Identifier [Axis]: Collective Trust Funds, Core Plus Fixed Income Fund      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 2,906,136    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement 2010 Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 889,414    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement 2015 Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 2,024,591    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement 2020 Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 6,076,947    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement 2025 Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 9,934,699    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement 2030 Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 12,913,620    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement 2035 Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 13,548,681    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement 2040 Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 15,970,906    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement 2045 Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 15,782,746    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement 2050 Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 10,366,898    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement 2055 Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 8,659,375    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement 2060 Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 3,697,938    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement 2065 Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 631,810    
Investment, Identifier [Axis]: Collective Trust Funds, Retirement Balanced Trust Class F      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 668,094    
Investment, Identifier [Axis]: Collective Trust Funds, Small/Mid Cap Core Equity Fund - Class I      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 5,793,085    
Investment, Identifier [Axis]: Common Stock, Everus      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 10,100,000 7,200,000  
Total investments 10,145,135    
Investment, Identifier [Axis]: Common Stock, MDU Resources      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments   $ 6,000,000.0  
Investment, Identifier [Axis]: Fully Benefit-Responsive Investment Contract, New York Life Anchor Account III      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 9,093,440    
Investment, Identifier [Axis]: Mutual Funds, 500 Index Fund      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 30,110,075    
Investment, Identifier [Axis]: Mutual Funds, Diversified Real Asset R6 Fund      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 55,569    
Investment, Identifier [Axis]: Mutual Funds, EUPAC R6 Fund      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 5,456,595    
Investment, Identifier [Axis]: Mutual Funds, Extended Market Index Fund      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 7,692,422    
Investment, Identifier [Axis]: Mutual Funds, Inflation Protected Bond Instl Fund      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 729,603    
Investment, Identifier [Axis]: Mutual Funds, International Value I Fund      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 7,097,095    
Investment, Identifier [Axis]: Mutual Funds, Large-Cap Growth Fund - I Class      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 21,149,538    
Investment, Identifier [Axis]: Mutual Funds, Total International Index Fund      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 3,116,981    
Investment, Identifier [Axis]: Mutual Funds, U.S. Bond Index Fund      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 6,142,814    
Investment, Identifier [Axis]: Mutual Funds, U.S. Equity Research Fund - I Class      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Total investments 10,687,897    
Common stock      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Cost of asset 2,600,000    
Selling price 1,800,000    
Realized gain (loss) $ 291,100    
Investment, number of shares (in shares) 118,573 109,231  
EBP, Nonemployer, Common Stock | Related party | MDU Resources      
EBP, Related Party and Party-in-Interest Transactions [Line Items]      
Selling price $ 6,000,000.0    
Realized gain (loss) $ (2,500,000)    
Investment, number of shares (in shares)   335,527