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Lines of Credit and Long-Term Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jul. 31, 2024	Dec. 31, 2023	Nov. 15, 2023
Debt Instrument [Line Items]
Weighted-average interest rate on short-term	6.61%		6.48%
Line of Credit \| Revolving Credit Facility
Debt Instrument [Line Items]
Unused portion of line of credit	$ 256,765
Senior Notes \| Connecticut Water Company \| Series 2023 Notes
Debt Instrument [Line Items]
Aggregate principal amount				$ 25,000
Interest rate				6.46%
Senior Notes \| Connecticut Water Company \| Series 2024 Notes
Debt Instrument [Line Items]
Aggregate principal amount		$ 50,000
Interest rate		5.78%
Senior Notes \| San Jose Water Company \| Series Q Notes
Debt Instrument [Line Items]
Aggregate principal amount		$ 75,000
Interest rate		5.63%