REGULATORY ASSETS (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Regulatory Assets [Abstract]
Contributions to postretirement benefit plan	$ 5,700
Cash received for bond issuance		$ 30,000,000
Amortization period of other regulatory expense [Abstract]
Rate case studies	5 years
Goodwill	50 years
Deferred acquisition costs	20 years
Franchise costs	80 years
Regulatory assets net of amortization, comprise [Abstract]
Regulatory assets, net	$ 6,785,000	6,891,000
Maximum [Member]
Amortization period of other regulatory expense [Abstract]
Debt related cost	30 years
Minimum [Member]
Amortization period of other regulatory expense [Abstract]
Debt related cost	15 years
Delaware [Member]
Amortization period of other regulatory expense [Abstract]
Regulatory rate proceedings	2 years 6 months
Maryland [Member]
Amortization period of other regulatory expense [Abstract]
Regulatory rate proceedings	5 years
Postretirement Benefit Obligation [Member]
Regulatory assets net of amortization, comprise [Abstract]
Regulatory assets, net	$ 51,000	51,000
Deferred Income Taxes [Member]
Regulatory assets net of amortization, comprise [Abstract]
Regulatory assets, net	382,000	386,000
Debt Related Costs [Member]
Regulatory assets net of amortization, comprise [Abstract]
Regulatory assets, net	25,000	27,000
Expense of Rate and Regulatory Proceedings [Member]
Regulatory assets net of amortization, comprise [Abstract]
Regulatory assets, net	5,468,000	5,556,000
Goodwill [Member]
Regulatory assets net of amortization, comprise [Abstract]
Regulatory assets, net	286,000	288,000
Deferred Acquisition and Franchise Costs [Member]
Regulatory assets net of amortization, comprise [Abstract]
Regulatory assets, net	$ 573,000	$ 583,000