FAIR VALUE MEASUREMENTS: Fair Value, by Balance Sheet Grouping (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Receivable, Fair Value Disclosure	$ 3,472	[1]	$ 3,472	[1]
Loans Payable, Fair Value Disclosure	1,615,441	[1]	1,616,322	[1]
Reported Value Measurement [Member] | Idaho Power Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Payable, Fair Value Disclosure	1,615,441	[1]	1,616,322	[1]
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Receivable, Fair Value Disclosure	3,472	[1]	3,472	[1]
Loans Payable, Fair Value Disclosure	1,672,271	[1]	1,600,248	[1]
Estimate of Fair Value Measurement [Member] | Idaho Power Company
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Payable, Fair Value Disclosure	$ 1,672,271	[1]	$ 1,600,248	[1]

[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 12.