Water And Wastewater Rates (Details) $ in Thousands		1 Months Ended	12 Months Ended
	May 24, 2019 USD ($)	May 31, 2019 USD ($)	Dec. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($) item	Dec. 31, 2017 USD ($) item
Water And Wastewater Rates [Line Items]
Increase in annual revenue due to rate filings			$ 76,493
Provision for income taxes (benefit)			$ (13,017)	$ (13,669)	$ 16,914
Infrastructure rehabilitation surcharge percentage, reset level upon new base rates			0.00%
Infrastructure rehabilitation surcharges			$ 16,007	31,836	10,255
Pennsylvania [Member]
Water And Wastewater Rates [Line Items]
Distribution system improvement charges	$ 29,493
Distribution system improvement charges over base rate	7.50%
Base rate increase designed to increase total operating revenues on an annual basis	$ 47,000
Target		$ 3,000
Provision for income taxes (benefit)		158,865
Revenues realized		28,396
New Jersey [Member]
Water And Wastewater Rates [Line Items]
Public Utilities, Approved Rate Increase (Decrease), Amount		5,000
Revenues realized		$ 2,917
Other Subsidiaries [Member]
Water And Wastewater Rates [Line Items]
Public Utilities, Approved Rate Increase (Decrease), Amount			$ 974	$ 11,558	$ 7,558
Number of rate decisions | item			2	5	5
Revenues realized			$ 974	$ 7,270	$ 6,343
Minimum [Member]
Water And Wastewater Rates [Line Items]
Infrastructure rehabilitation surcharges, capped percentage			5.00%
Maximum [Member]
Water And Wastewater Rates [Line Items]
Infrastructure rehabilitation surcharges, capped percentage			12.75%