FAIR VALUE MEASUREMENTS: Fair Value Carrying Amounts and Estimated Fair Values (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable	[1]	$ 3,804	$ 3,804
Long-term debt	[1]	1,836,659	1,834,788
Carrying Amount | Idaho Power Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	[1]	1,836,659	1,834,788
Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable	[1]	3,804	3,804
Long-term debt	[1]	2,083,931	1,942,773
Estimated Fair Value | Idaho Power Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	[1]	$ 2,083,931	$ 1,942,773

[1] Notes receivable and long-term debt are categorized as Level 3 and Level 2, respectively, of the fair value hierarchy, as defined earlier in this Note 17 - "Fair Value Measurements."