FAIR VALUE MEASUREMENTS: Fair Value, by Balance Sheet Grouping (Details) - USD ($) $ in Thousands		Mar. 31, 2022	Dec. 31, 2021
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Receivable	[1]	$ 3,804	$ 3,804
Held-to-maturity securities	[1]	29,366	0
Long-term debt	[1]	2,050,634	2,000,640
Carrying Amount | Idaho Power Company [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	[1]	29,366	0
Long-term debt	[1]	2,050,634	2,000,640
Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Receivable	[1]	3,804	3,804
Held-to-maturity securities	[1]	27,521	0
Long-term debt	[1]	2,166,197	2,381,172
Estimated Fair Value | Idaho Power Company [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	[1]	27,521	0
Long-term debt	[1]	$ 2,166,197	$ 2,381,172

[1] Notes receivable are categorized as Level 3 and held-to-maturity securities and long-term debt are categorized as Level 2 of the fair value hierarchy, as defined earlier in this Note 13 - "Fair Value Measurements."