REGULATORY PROCEEDINGS (Details) - USD ($)				3 Months Ended
	Nov. 29, 2016	May 31, 2016	Nov. 24, 2015	Mar. 31, 2017	Mar. 31, 2016
Other Proceedings [Abstract]
Percentage of Distribution System Improvement Charges annual rate increase application filed by company to regulatory	4.71%	2.30%	1.57%
Increase Amount Based On Eligible Plant Improvements Since Last Rate Increase	$ 16,600,000	$ 10,300,000	$ 7,000,000
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 earned in DSIC rate increases				$ 756,000	$ 249,000