REGULATORY PROCEEDINGS (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2016
Other Proceedings [Abstract]
Cumulative DSIC Rate	3.63%		3.63%		4.71%
Eligible Plant Improvements - Cumulative Dollars			$ 24,700,000		$ 16,600,000
Delaware [Member]
Rate Proceedings [Abstract]
Percentage of gross water sales			15.00%
Period to complete rate case by law			7 months
Delaware [Member] | Maximum [Member]
Rate Proceedings [Abstract]
Temporary annual rate increase subject to 15% gross water sales limitation			$ 2,500,000
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 held in reserve pending outcome of TCJA impact to customers	$ 655,000		$ 2,203,000
Revenue earned in DSIC rate increases	$ 0	$ 858,000	$ 0	$ 2,401,000