CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Reclassification out of Accumulated Other Comprehensive Income
Amortization of prior service cost	[1]	$ 74	$ 73	$ 148	$ 145
Amortization of net loss	[1]	1,052	933	2,103	1,867
Total reclassification, before tax - pension and postretirement benefits		1,126	1,006	2,251	2,012
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	[2]	(290)	(259)	(579)	(518)
Reclassifications		836	747	1,672	1,494
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
AOCI - Beginning Balance		(42,522)	(35,537)	(43,358)	(36,284)
Reclassifications		836	747	1,672	1,494
AOCI - Ending Balance		(41,686)	(34,790)	(41,686)	(34,790)
Accumulated Defined Benefit Pension Items
Reclassification out of Accumulated Other Comprehensive Income
Reclassifications		836	747	1,672	1,494
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
AOCI - Beginning Balance		(42,522)	(35,537)	(43,358)	(36,284)
Reclassifications		836	747	1,672	1,494
AOCI - Ending Balance		$ (41,686)	$ (34,790)	$ (41,686)	$ (34,790)

[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.