REGULATORY PROCEEDINGS (Details) - USD ($) $ in Millions						12 Months Ended
	Nov. 28, 2018	May 31, 2018	Nov. 29, 2016	May 31, 2016	Nov. 24, 2015	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2019
Water and Wastewater Rates [Abstract]
Amount refunded to customers									$ 3.8
Other Proceedings [Abstract]
Cumulative DSIC Rate	7.50%	7.41%	5.55%	3.63%	4.71%
Net Eligible Plant Improvements - Cumulative Dollars	$ 43.1	$ 43.1	$ 30.4	$ 24.7	$ 16.6
Delaware [Member]
Water and Wastewater Rates [Abstract]
Temporary annual rate increase subject to 15% gross water sales limitation						$ 2.5
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]
Other Proceedings [Abstract]
Revenue earned in DSIC rate increases						$ 4.3	$ 2.8	$ 3.2