OTHER DEFERRED CHARGES (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Deferred Costs [Abstract]
Preliminary surveys and investigations	$ 14,946	$ 12,845
Advances to operating agents of jointly owned facilities	8,457	2,750
Lease right-of-use assets	10,280	6,477
Other	18,818	14,049
Total other deferred charges	$ 52,501	$ 36,121

Net amount of other deferred costs capitalized at the end of the reporting period. Does not include deferred finance costs or deferred acquisition costs of insurance companies.

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(17))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Name:	us-gaap_OtherDeferredCostsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant