REGULATORY MATTERS: Open Access Transmission Tariff Rates (Details) - Federal Open Access Transmission Tariff Rates - USD ($)	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Open Access Transmission Tariff Rates [Line Items]
Load Change Adjustment Rate Or Open Access Same Time Draft Rates	$ 23.43	$ 22.48	$ 22.80	$ 21.29
Net Annual Transmission Revenue Requirement	$ 121,300,000

The load change adjustment rate is an element of the rate mechanism that recognizes the power supply expenses recovered through base rates change as loads increase or decrease. Rate is per megawatt-hour. This tag can also represent the open access same time draft rate, which is stated in kW/yr.

No definition available.

Name:	ida_LoadChangeAdjustmentRateOrOpenAccessSameTimeDraftRates
Namespace Prefix:	ida_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant