Commitments and Contingent Liabilities (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) gal	Jun. 30, 2021 USD ($)
Purchase Commitment, Excluding Long-Term Commitment [Line Items]
Construction program | $			$ 90.0
Estimated obligation expenditure | $			35.0
Rental expenses under operating leases | $	$ 0.2	$ 0.2	$ 0.4	$ 0.4
Estimated incremental borrowing rate	4.03%		4.03%
NJ Water Supply Authority [Member]
Purchase Commitment, Excluding Long-Term Commitment [Line Items]
Purchase commitment expiration date of contract			Nov. 30, 2023
Water purchase per commitment | gal			27
Regulated Water Authority [Member]
Purchase Commitment, Excluding Long-Term Commitment [Line Items]
Purchase commitment expiration date of contract			Feb. 27, 2026
Water purchase per commitment | gal			3
City of Dover [Member]
Purchase Commitment, Excluding Long-Term Commitment [Line Items]
Water purchase per commitment | gal			15