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Rate and Regulatory Matters (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Regulatory Liabilities [Line Items]
Deferred income tax benefits	$ (2,319)	$ 117
Middlesex [Member] | New Jersey Board Of Public Utilities [Member]
Regulatory Liabilities [Line Items]
Additional annual costs	100
Tidewater [Member] | Delaware Public Service Commission Member
Regulatory Liabilities [Line Items]
Approved increase in annual operating revenues	$ 200
Corporate tax rate	3.35%
Base rate amount	$ 1,000
Line of credit	700
Pinelands Water Company [Member]
Regulatory Liabilities [Line Items]
Approved increase in annual operating revenues	200
Pinelands Wastewater [Member]
Regulatory Liabilities [Line Items]
Approved increase in annual operating revenues	$ 500

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