REGULATORY PROCEEDINGS (Details) - USD ($)							12 Months Ended
	Nov. 29, 2016	May 31, 2016	Nov. 24, 2015	Aug. 18, 2015	May 28, 2015	Nov. 26, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Proceedings [Abstract]
Percentage of Distribution System Improvement Charges annual rate increase application filed by company to regulatory	4.71%	2.30%	1.57%		1.15%	0.34%
Increase Amount Based On Eligible Plant Improvements Since Last Rate Increase	$ 16,600,000	$ 10,300,000	$ 7,000,000		$ 4,600,000	$ 1,300,000
Delaware [Member]
Rate Proceedings [Abstract]
Temporary annual rate increase subject to 15% gross water sales limitation							$ 2,500,000
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]
Rate Proceedings [Abstract]
Percentage of revenue increase requested for new rates				15.90%
Increase in annual revenue expected from rate increase application approval				$ 10,000,000
Permanent rate increase in revenue				$ 6,000,000
Percentage of Permanent Rate Increases on an annualized basis (in hundredths)				9.50%
An incremental increase to customers above the DSIC rate previously in effect				6.20%
Other Proceedings [Abstract]
Revenue earned in DSIC rate increases							$ 1,306,000	$ 520,000	$ 788,000