REGULATORY PROCEEDINGS (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2020
Other Proceedings [Abstract]
Cumulative DSIC Rate	7.41%		7.41%	7.41%			5.55%	7.50%
Net Eligible Plant Improvements - Cumulative Dollars			$ 43.1	$ 43.1		$ 43.1	$ 30.4
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				$ 3.8
Delaware [Member] | Maximum [Member]
Rate Proceedings [Abstract]
Temporary annual rate increase subject to 15% gross water sales limitation				$ 2.5
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	$ 1.4	$ 1.3		$ 3.8	$ 3.1