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Organization, Summary of Significant Accounting Policies and Recent Developments (Narrative) (Details) - USD ($) $ in Millions | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Nov. 30, 2015 | Dec. 31, 2015 | Jun. 30, 2015 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Organization, Summary Of Significant Accounting Policies And Recent Developments [Line Items] |  |  |  |  |  |
Percent voting interest |  |  |  | 50.00% |  |
Percent of operating revenues |  |  |  | 88.00% |  |
Percent of total assets |  |  |  | 99.00% |  |
Allowance for doubtful accounts |  | $ 0.8 |  | $ 0.8 | $ 0.7 |
Bad debt expense |  |  |  | 0.8 | 0.7 | $ 0.7
Write-offs |  |  |  | $ 0.6 | $ 0.6 | $ 0.9
Pinelands Water [Member] |  |  |  |  |  |
Organization, Summary Of Significant Accounting Policies And Recent Developments [Line Items] |  |  |  |  |  |
Originally filed increase in annual operating revenue |  | 0.3 |  |  |  |
Pinelands Wastewater [Member] |  |  |  |  |  |
Organization, Summary Of Significant Accounting Policies And Recent Developments [Line Items] |  |  |  |  |  |
Originally filed increase in annual operating revenue |  | 0.2 |  |  |  |
Twin Lakes [Member] |  |  |  |  |  |
Organization, Summary Of Significant Accounting Policies And Recent Developments [Line Items] |  |  |  |  |  |
Originally filed increase in annual operating revenue | $ 0.2 | $ 0.2 |  |  |  |
New Jersey Board of Public Utilities [Member] |  |  |  |  |  |
Organization, Summary Of Significant Accounting Policies And Recent Developments [Line Items] |  |  |  |  |  |
Approved increase in annual operating revenues |  |  | $ 5.0 |  |  |

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