REGULATORY PROCEEDINGS (Details) - USD ($) $ in Millions						6 Months Ended	12 Months Ended
	Nov. 20, 2020	May 29, 2020	Nov. 15, 2019	May 29, 2019	Nov. 28, 2018	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Proceedings [Abstract]
Cumulative DSIC Rate	7.50%	7.50%	7.50%	7.41%	5.55%
Net Eligible Plant Improvements - Cumulative Dollars	$ 43.1	$ 43.1	$ 43.1	$ 43.1	$ 30.4
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%
Revenue returned to customers as a result of TCJA						$ 3.8
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							$ 5.0	$ 4.3	$ 2.8