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REGULATORY PROCEEDINGS (Details) - USD ($) |  |  |  |  |  |  | 12 Months Ended
--- | --- | --- | --- | --- | --- | --- | ---
Nov. 29, 2016 | May 31, 2016 | Nov. 24, 2015 | Aug. 18, 2015 | May 28, 2015 | Nov. 26, 2014 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Other Proceedings [Abstract] |  |  |  |  |  |  |  |  |
Percentage of Distribution System Improvement Charges annual rate increase application filed by company to regulatory | 4.71% | 2.30% | 1.57% |  | 1.15% | 0.34% |  |  |
Increase Amount Based On Eligible Plant Improvements Since Last Rate Increase | $ 16,600,000 | $ 10,300,000 | $ 7,000,000 |  | $ 4,600,000 | $ 1,300,000 |  |  |
Delaware [Member] |  |  |  |  |  |  |  |  |
Rate Proceedings [Abstract] |  |  |  |  |  |  |  |  |
Temporary annual rate increase subject to 15% gross water sales limitation |  |  |  |  |  |  | $ 2,500,000 |  |
Percentage of gross water sales |  |  |  |  |  |  | 15.00% |  |
Period to complete rate case by law |  |  |  |  |  |  | 7 months |  |
Percentage of rate relief allowed should a rate case not complete |  |  |  |  |  |  | 15.00% |  |
Other Proceedings [Abstract] |  |  |  |  |  |  |  |  |
Distribution System Improvement Charge rate increase applied between base rate filings |  |  |  |  |  |  | 7.50% |  |
Distribution System Improvement Charge rate increase within a 12-month period |  |  |  |  |  |  | 5.00% |  |
Artesian Water [Member] |  |  |  |  |  |  |  |  |
Rate Proceedings [Abstract] |  |  |  |  |  |  |  |  |
Percentage of revenue increase requested for new rates |  |  |  | 15.90% |  |  |  |  |
Increase in annual revenue expected from rate increase application approval |  |  |  | $ 10,000,000 |  |  |  |  |
Permanent rate increase in revenue |  |  |  | $ 6,000,000 |  |  |  |  |
Percentage of Permanent Rate Increases on an annualized basis (in hundredths) |  |  |  | 9.50% |  |  |  |  |
An incremental increase to customers above the DSIC rate previously in effect |  |  |  | 6.20% |  |  |  |  |
Other Proceedings [Abstract] |  |  |  |  |  |  |  |  |
Revenue earned in DSIC rate increases |  |  |  |  |  |  | $ 1,306,000 | $ 520,000 | $ 788,000

X
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- Definition Ceiling percentage of Distribution System Improvement Charge rate subject to amount billed to customers. + References No definition available. + Details
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- Definition Conditional percentage maximum for increasing Distribution System Improvement Charge rate within a 12-month period. + References No definition available. + Details
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