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Rate and Regulatory Matters (Narrative) (Details) - USD ($) $ in Thousands | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Nov. 30, 2016 | Jun. 30, 2016 | Apr. 30, 2016 | Nov. 30, 2015 | Oct. 31, 2015 | Aug. 31, 2015 | Oct. 31, 2014 | Aug. 31, 2014 | Jun. 30, 2014 | Dec. 31, 2016 | Dec. 31, 2015
Regulatory Liabilities [Line Items] |  |  |  |  |  |  |  |  |  |  |
Regulatory Liability - Cost of Utility Plant Removal |  |  |  |  |  |  |  |  |  | $ 11,337 | $ 10,876
Acquisition premiums to be recovered |  |  |  |  |  |  |  |  |  | 500 |
Pinelands Water Company [Member] |  |  |  |  |  |  |  |  |  |  |
Regulatory Liabilities [Line Items] |  |  |  |  |  |  |  |  |  |  |
Approved increase in annual operating revenues |  |  | $ 200 |  |  |  |  |  |  |  |
Originally filed increase in annual operating revenue |  |  |  |  | $ 500 |  |  |  |  |  |
Pinelands Wastewater [Member] |  |  |  |  |  |  |  |  |  |  |
Regulatory Liabilities [Line Items] |  |  |  |  |  |  |  |  |  |  |
Approved increase in annual operating revenues |  |  | $ 100 |  |  |  |  |  |  |  |
Twin Lakes [Member] |  |  |  |  |  |  |  |  |  |  |
Regulatory Liabilities [Line Items] |  |  |  |  |  |  |  |  |  |  |
Approved increase in annual operating revenues |  | $ 100 |  |  |  |  |  |  |  |  |
Originally filed increase in annual operating revenue |  |  |  | $ 200 |  |  |  |  |  |  |
New Jersey Board Of Public Utilities [Member] |  |  |  |  |  |  |  |  |  |  |
Regulatory Liabilities [Line Items] |  |  |  |  |  |  |  |  |  |  |
Approved increase in annual operating revenues |  |  |  |  |  | $ 5,000 |  |  |  |  |
New Jersey Board Of Public Utilities [Member] | Middlesex [Member] |  |  |  |  |  |  |  |  |  |  |
Regulatory Liabilities [Line Items] |  |  |  |  |  |  |  |  |  |  |
Approved increase in annual operating revenues |  |  |  |  |  |  |  |  | $ 4,200 |  |
Originally filed increase in annual operating revenue | $ 100 |  |  |  |  |  |  |  |  |  |
Amended filed increase in annual operating revenue |  |  |  |  |  |  |  |  |  | 5,000 |
Base rate amount |  |  |  |  |  |  |  |  | $ 208,600 | $ 219,000 |
Return on equity |  |  |  |  |  |  |  |  | 9.75% | 9.75% |
New Jersey Board Of Public Utilities [Member] | TESI [Member] |  |  |  |  |  |  |  |  |  |  |
Regulatory Liabilities [Line Items] |  |  |  |  |  |  |  |  |  |  |
Approved increase in annual operating revenues |  |  |  |  |  |  | $ 100 |  |  |  |
Delaware Public Service Commission [Member] | Tidewater [Member] |  |  |  |  |  |  |  |  |  |  |
Regulatory Liabilities [Line Items] |  |  |  |  |  |  |  |  |  |  |
Approved increase in annual operating revenues |  |  |  |  |  |  |  |  |  | $ 300 |
Amended filed increase in annual operating revenue |  |  |  |  |  |  |  | $ 800 |  |  |
Base rate amount |  |  |  |  |  |  |  |  |  | $ 208,600 |
Return on equity |  |  |  |  |  |  |  |  |  | 9.75% |
Delaware Public Service Commission [Member] | TESI [Member] |  |  |  |  |  |  |  |  |  |  |
Regulatory Liabilities [Line Items] |  |  |  |  |  |  |  |  |  |  |
Approved increase in annual operating revenue (percentage) |  |  |  |  |  |  | 33.50% |  |  |  |
Delaware Public Service Commission [Member] | Southern Shores [Member] |  |  |  |  |  |  |  |  |  |  |
Regulatory Liabilities [Line Items] |  |  |  |  |  |  |  |  |  |  |
Originally filed increase in annual operating revenue |  |  |  |  |  |  |  |  |  | $ 100 |

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