BASIS OF PRESENTATION, CORPORATE TRANSACTIONS, SIGNIFICANT ACCOUNTING POLICIES, AND RECENT ACCOUNTING PRONOUNCEMENTS - Corporate Transactions (Details)				3 Months Ended
	Jun. 08, 2023 USD ($) $ / shares shares	Feb. 01, 2023 USD ($) mi² service_connection	Jul. 14, 2015 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Oct. 26, 2023 USD ($)	Jun. 24, 2016 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Advances in aid of construction				$ 6,700,000
Growth premiums received				800,000	$ 400,000
Accumulated growth premiums received				$ 11,500,000
Farmers Water Company
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of active water connections | service_connection		3,300
Square miles of approved service area | mi²		21.5
Maximum payout of growth premium receivable		$ 3,500,000
Growth premiums received		$ 1,400,000
Valencia Water Company
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Growth premium receivable for each new water meter installed			$ 3,000,000
Period for maximum payout of growth premium receivable			20 years
Maximum payout of growth premium receivable			$ 45,000,000
Private Placement Offering
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of common stock to be issued and sold (in shares) | shares	230,000
Purchase price (in dollars per share) | $ / shares	$ 12.07
Gross proceeds from sale of stock	$ 2,800,000
Private Placement Offering | Affiliates
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of common stock issued (in shares) | shares	30,000
Senior Notes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt instrument, interest rate							4.55%
Aggregate amount							$ 115,000,000
$6.91% Senior Secured Notes, maturing January 2034 | Senior Notes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt instrument, interest rate				6.91%		6.91%
Aggregate amount						$ 20,000,000