CHANGES IN ACCUMULATED OTHER COMPREHENSIVE INCOME Reclassifications out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reclassifications out of Accumulated Other Comprehensive Income before Tax [Abstract]
Reclassifications		$ 1,952	$ 2,886	$ 1,882
Accumulated Defined Benefit Pension Items
Reclassifications out of Accumulated Other Comprehensive Income before Tax [Abstract]
Amortization of prior service cost	[1]	96	98	127
Amortization of net loss	[1]	2,533	3,788	2,963
Total reclassifications, before tax - pension and postretirement benefits	[1]	2,629	3,886	3,090
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	[2]	(677)	(1,000)	(1,208)
Total reclassification, net of tax - pension and postretirement benefits		1,952	2,886	1,882
Reclassifications		$ 1,952	$ 2,886	$ 1,882

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

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