INVESTMENTS: Investments Level 4 (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Summary of investments in debt and equity securities
Equity method investment	$ 9,897	$ 10,311
Investments in affordable housing	57,286	29,454
Other Investments	3,751	2,796
Total investments	163,971	121,352
Earnings of unconsolidated equity-method investments	12,426	11,511	$ 11,435
Debt Securities, Held-to-Maturity, Purchase	$ (1,617)	(31,224)	0
Idaho Power Company
Summary of investments in debt and equity securities
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	33.00%
Corporate Fixed-Income And Asset-Backed Debt Securities
Summary of investments in debt and equity securities
Debt Securities, Held-to-Maturity, Purchase	$ 1,600	31,200
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value	3,300	5,000
Idaho Power Company
Summary of investments in debt and equity securities
Equity method investment	24,078	14,187
Cash, Cash Equivalents, and Short-term Investments	36,617	33,687
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss, Noncurrent	31,639
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss, Current	30,475
Executive Deferred Compensation Plan Assets	703	442
Total investments	$ 93,037	78,791
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	33.00%
Earnings of unconsolidated equity-method investments	$ 10,540	10,211	10,211
Proceeds from sales	8,921	63,857	11,328
Gross realized gains from sales	0	0	0
Debt Securities, Held-to-Maturity, Purchase		(31,224)	0
Bridger Coal Company
Summary of investments in debt and equity securities
Earnings of unconsolidated equity-method investments	$ 10,540	10,211	10,211
Ida-West Energy
Summary of investments in debt and equity securities
Jointly Owned Utility Plant, Proportionate Ownership Share	50.00%
Earnings of unconsolidated equity-method investments	$ 1,886	$ 1,300	$ 1,224

Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(9))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1