CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Reclassification out of Accumulated Other Comprehensive Income
Amortization of prior service cost	[1]	$ 74	$ 72
Amortization of net loss	[1]	1,051	934
Total reclassification, before tax - pension and postretirement benefits		1,125	1,006
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	[2]	(289)	(259)
Reclassifications		836	747
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
AOCI - Beginning Balance		(43,358)	(36,284)
Reclassifications		836	747
AOCI - Ending Balance		(42,522)	(35,537)
Accumulated Defined Benefit Pension Items
Reclassification out of Accumulated Other Comprehensive Income
Reclassifications		836	747
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
AOCI - Beginning Balance		(43,358)	(36,284)
Reclassifications		836	747
AOCI - Ending Balance		$ (42,522)	$ (35,537)

[1] Amortization of these items is included in IDACORP's condensed consolidated income statements in other operating expenses and in Idaho Power's condensed consolidated statements of income in other expense, net.

[2] The tax benefit is included in income tax expense in the condensed consolidated statements of income of both IDACORP and Idaho Power.