INCOME TAXES: Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Deferred tax assets:
Regulatory liabilities	$ 121,489	$ 127,634
Deferred compensation	24,483	24,782
Deferred revenue	70,326	64,592
Tax credits	70,854	66,783
Partnership investments	24,157	18,450
Retirement benefits	19,533	26,495
Other	37,884	24,869
Total	368,726	353,605
Deferred tax liabilities:
Property, plant and equipment	235,849	243,454
Regulatory assets	821,346	811,054
Partnership investments	4,309	4,613
Retirement benefits	65,214	75,716
Deferred Tax Liabilities, Regulatory Assets	22,252	16,272
Other	22,641	24,727
Total	1,171,611	1,175,836
Net deferred tax liabilities	802,885	822,231
Idaho Power Company
Deferred tax assets:
Regulatory liabilities	121,489	127,634
Deferred compensation	24,483	24,782
Deferred revenue	70,326	64,592
Tax credits	67,930	53,859
Partnership investments	24,157	18,450
Retirement benefits	19,533	26,495
Other	37,831	24,826
Total	365,749	340,638
Deferred tax liabilities:
Property, plant and equipment	235,849	243,454
Regulatory assets	821,346	811,054
Partnership investments	0	0
Retirement benefits	65,214	75,716
Deferred Tax Liabilities, Regulatory Assets	22,252	16,272
Other	22,027	23,588
Total	1,166,688	1,170,084
Net deferred tax liabilities	$ 800,939	$ 829,446

The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the tax basis of pension liabilities funded in advance and the basis of a prepaid pension asset determined in accordance with generally accepted accounting principles. The difference in basis of such costs will increase future taxable income when such basis difference reverses. Prepaid pension costs represented the cumulative employer's contributions in excess of net pension cost recognized, before the adoption of the recognition provisions of FAS 158. Under FAS 158, prepaid pension costs are no longer recognized in the statement of financial position.

No definition available.