INVESTMENTS: Investments Level 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary of investments in debt and equity securities
Equity method investment	$ 11,123	$ 11,393
Exchange traded short-term bond funds and cash equivalents	24,459	44,942
Investments in affordable housing	9,909	12,762
Total investments	140,752	165,458
Earnings Losses of Unconsolidated Equity-Method Investments	11,128	12,372	$ 11,939
Idaho Power Company
Summary of investments in debt and equity securities
Equity method investment	95,159	96,219
Exchange traded short-term bond funds and cash equivalents	24,459	44,942
Executive Deferred Compensation Plan Assets	102	141
Other investments	0	1
Total investments	$ 119,720	141,303
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	33.00%
Earnings Losses of Unconsolidated Equity-Method Investments	$ 9,773	10,814	10,242
Proceeds from sales	34,243	0	25,661
Gross realized gains from sales	0	0	11,637
Gross realized losses from sales	0	0	0
Bridger Coal Company
Summary of investments in debt and equity securities
Earnings Losses of Unconsolidated Equity-Method Investments	$ 9,773	10,814	10,242
Ida-West Energy
Summary of investments in debt and equity securities
Jointly Owned Utility Plant, Proportionate Ownership Share	50.00%
Earnings Losses of Unconsolidated Equity-Method Investments	$ 1,355	1,614	1,707
IDACORP Financial Services Limited Partnership Interests
Summary of investments in debt and equity securities
Earnings Losses of Unconsolidated Equity-Method Investments	$ 0	$ (56)	$ (10)