LONG-TERM DEBT - Narrative (Details) - USD ($) $ in Thousands	Oct. 22, 2024	Dec. 31, 2025	Oct. 01, 2025	Dec. 31, 2024	Oct. 04, 2011
Long-term debt
Total		$ 12,467		$ 13,503
Cal Water
Long-term debt
Operating lease term					15 years
Total		$ 700		$ 1,600
Senior Unsecured Notes Due On October 1, 2032
Long-term debt
Principal amount			$ 70,000
Interest rate			4.87%
Senior Unsecured Notes Due On October 1, 2035
Long-term debt
Principal amount			$ 100,000
Interest rate			5.22%
Senior Unsecured Notes Due On October 1, 2055
Long-term debt
Principal amount			$ 200,000
Interest rate			5.64%
Secured Debt
Long-term debt
Principal amount	$ 125,000
Secured Debt | Cal Water
Long-term debt
Interest rate	5.22%