v3.25.1
REVENUES: (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers $ 411,142 $ 417,897
Alternative revenue programs and other revenues 20,810 30,402
Retail revenues    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers 356,213 343,157
Idaho fixed cost adjustment mechanism    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers [1] 2,236 740
Alternative revenue programs and other revenues (2,236) (740)
Wholesale energy sales    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers 19,548 38,069
Transmission Service Agreement    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers 19,442 24,162
Energy efficiency program revenues    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers 5,232 4,291
Other revenues    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers 8,471 7,478
Derivative revenues    
Disaggregation of Revenue [Line Items]    
Alternative revenue programs and other revenues 23,046 31,142
Residential Retail Revenue | Retail revenues    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers [1] 190,705 184,300
Residential Retail Revenue | Idaho fixed cost adjustment mechanism    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers (2,193) (687)
Commercial Retail Revenue | Retail revenues    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers [1] 97,852 94,697
Commercial Retail Revenue | Idaho fixed cost adjustment mechanism    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers (43) (53)
Industrial Retail Revenue | Retail revenues    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers 68,607 65,206
Irrigation Retail Revenue | Retail revenues    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers 1,113 1,038
Deferred revenue-AFUDC | Retail revenues    
Disaggregation of Revenue [Line Items]    
Revenue from contracts with customers [2] (2,064) (2,084)
IPUC authorized AFUDC Collection HCC Relicensing - Gross | Idaho Power Company | Hells Canyon Complex    
Disaggregation of Revenue [Line Items]    
Regulatory liabilities $ (8,800) $ (8,800)
[1] The FCA mechanism is an alternative revenue program in the Idaho jurisdiction and does not represent revenue from contracts with customers.
[2] The IPUC allows Idaho Power to recover a portion of the AFUDC on construction work in progress related to the HCC relicensing process, even though the relicensing process is not yet complete and the costs have not been moved to utility plant in service. Idaho Power is collecting $8.8 million annually in the Idaho jurisdiction but is deferring revenue recognition of the amounts collected until the license is issued and the accumulated license costs approved for recovery are placed in service.