CHANGES IN IDAHO POWER RETAINED EARNINGS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Changes in Retained Earnings [Line Items]
Balance at beginning of period	$ 1,664,468	$ 1,563,399	$ 1,634,525	$ 1,531,543
Net Income	102,302	90,218	200,419	186,255
Dividends to parent			(101,999)	(95,871)
Common stock dividends	(33,960)	(31,933)	(101,896)	(95,919)
Balance at end of period	1,732,539	1,621,342	1,732,539	1,621,342
Idaho Power Company
Changes in Retained Earnings [Line Items]
Balance at beginning of period	1,531,566	1,438,019	1,503,805	1,409,245
Net Income	100,389	87,979	196,089	180,740
Dividends to parent	(33,959)	(31,932)	(101,898)	(95,919)
Balance at end of period	$ 1,597,996	$ 1,494,066	$ 1,597,996	$ 1,494,066