Demand-side management expenditures funded through a rider mechanism on customer bills.

No definition available.

Name:	ida_DemandSideManagementRiderMechanism
Namespace Prefix:	ida_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Name:	ida_IdahoPowerCostAdjustmentMechanismLineItems
Namespace Prefix:	ida_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Total amount of increase or (decrease) in rates, whether approved or requested, as a result of the related rate case.

No definition available.

Name:	ida_IncreaseDecreaseInRates
Namespace Prefix:	ida_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

Net PCA rate increase after the impact of the offset of revenue sharing with customers.

No definition available.

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

Percentage of earnings to be Shared with Customers that is above the maximum authorized rate of return in the rate case.

No definition available.

Name:	ida_PercentageToBeSharedWithCustomers
Namespace Prefix:	ida_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Percentage of earnings to be Shared with the Entity that is above the maximum authorized rate of return in the rate case.

No definition available.

Name:	ida_PercentageToBeSharedWithEntity
Namespace Prefix:	ida_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The percentage of expences associated with PURPA power purchases that is allocated to customers.

No definition available.

Name:	ida_PercetangeSharingOfExpensesAssociatedWithPurpaPurchases
Namespace Prefix:	ida_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

REGULATORY MATTERS: Idaho Power Cost Adjustment Mechanism (Details) (Idaho Power Cost Adjustment, USD $)	Dec. 31, 2012	Jun. 01, 2012	Jun. 01, 2011	Jun. 01, 2010
Idaho Power Cost Adjustment
Idaho Power Cost Adjustment Mechanism [Line Items]
Percentage to be Shared with Customers	95.00%
Percentage to be Shared with Entity	5.00%
Percetange Sharing of Expenses Associated with PURPA Purchases	100.00%
Increase (Decrease) in Rates		$ 43,000,000	$ (40,400,000)	$ (146,900,000)
Net PCA Rate Increase with Revenue Sharing		15,900,000
Demand-Side Management Rider Mechanism			$ 10,000,000