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REGULATORY PROCEEDINGS (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018 | Dec. 31, 2018 | Dec. 31, 2016
Other Proceedings [Abstract] |  |  |  |  |  |  |  |
Cumulative DSIC Rate |  |  | 7.41% | 3.63% |  |  | 5.55% | 4.71%
Eligible Plant Improvements - Cumulative Dollars |  |  | $ 43,100 | $ 24,700 |  |  | $ 30,400 | $ 16,600
Delaware [Member] |  |  |  |  |  |  |  |
Rate Proceedings [Abstract] |  |  |  |  |  |  |  |
Percentage of gross water sales |  |  |  |  | 15.00% |  |  |
Period to complete rate case by law |  |  |  |  | 7 months |  |  |
Revenue returned to customers as a result of TCJA |  |  |  |  | $ 3,800 |  |  |
Delaware [Member] | Maximum [Member] |  |  |  |  |  |  |  |
Rate Proceedings [Abstract] |  |  |  |  |  |  |  |
Temporary annual rate increase subject to 15% gross water sales limitation |  |  |  |  | $ 2,500 |  |  |
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] |  |  |  |  |  |  |  |
Other Proceedings [Abstract] |  |  |  |  |  |  |  |
Revenue earned in DSIC rate increases | $ 1,300 | $ 700 |  |  | $ 3,100 | $ 2,200 |  |

X
- Definition For a first temporary increase in revenue basis, maximum temporary annual rate charge increase subject to specific gross water sales limitation. + References No definition available. + Details
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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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