CHANGES IN IDAHO POWER RETAINED EARNINGS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Changes in Retained Earnings [Line Items]
Balance at beginning of period	$ 1,734,103	$ 1,634,525
Net Income	44,800	37,458
Dividends to parent	(36,379)	(34,312)
Common stock dividends	(35,940)	(33,950)
Balance at end of period	1,742,994	1,638,065
Idaho Power Company
Changes in Retained Earnings [Line Items]
Balance at beginning of period	1,599,155	1,503,805
Net Income	44,369	36,776
Dividends to parent	(35,941)	(33,952)
Balance at end of period	$ 1,607,583	$ 1,506,629