FAIR VALUE MEASUREMENTS: Level 4 (Details) - USD ($)		Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	[1]	$ 50,399,000	$ 97,833,000
Derivative Assets		4,285,000	3,655,000
Equity Securities, FV-NI		34,795,000	36,488,000
Derivative Liabilities		3,442,000	974,000
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount		0	0
Idaho Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds		30,981,000	79,228,000
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	[1]	50,399,000	97,833,000
Derivative Assets		4,088,000	3,655,000
Equity Securities, FV-NI		34,795,000	36,488,000
Derivative Liabilities		3,442,000	870,000
Fair Value, Inputs, Level 1 [Member] | Idaho Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds		30,981,000	79,228,000
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	[1]	0	0
Derivative Assets		197,000	0
Equity Securities, FV-NI		0	0
Derivative Liabilities		0	104,000
Fair Value, Inputs, Level 2 [Member] | Idaho Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds		0	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	[1]	0	0
Derivative Assets		0	0
Equity Securities, FV-NI		0	0
Derivative Liabilities		0	0
Fair Value, Inputs, Level 3 [Member] | Idaho Power Company
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds		$ 0	$ 0

[1] Holding company only. Does not include amounts held by Idaho Power.