SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Part 1 (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) Subsidiary	Dec. 31, 2018 USD ($)	Dec. 31, 2017
Utility Subsidiary Accounting [Abstract]
Number of wholly owned subsidiaries | Subsidiary	5
Summary of utility plant comprises [Abstract]
Utility plant, gross	$ 667,309	$ 624,792
Less - accumulated depreciation	136,588	126,114
Utility plant, net	$ 530,721	$ 498,678
Depreciation and Amortization [Abstract]
Depreciation rates of water utility plant	2.27%	2.28%	2.27%
Minimum [Member]
Depreciation and Amortization [Abstract]
Amortization period of other deferred assets	20 years
Maximum [Member]
Depreciation and Amortization [Abstract]
Amortization period of other deferred assets	24 years
Property Held for Future Use [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	0 years
Utility plant, gross	$ 24,632	$ 24,395
Construction in Progress [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	0 years
Utility plant, gross	$ 31,881	19,694
Utility plant in service-Water [Member] | Mains [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	81 years
Utility plant, gross	$ 277,125	267,352
Utility plant in service-Water [Member] | Services [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	39 years
Utility plant, gross	$ 48,190	45,661
Utility plant in service-Water [Member] | Storage Tanks [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	76 years
Utility plant, gross	$ 27,968	25,167
Utility plant in service-Water [Member] | Meters [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	26 years
Utility plant, gross	$ 27,498	26,531
Utility plant in service-Water [Member] | Hydrants [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	60 years
Utility plant, gross	$ 15,071	14,514
Utility plant in service-Water [Member] | Intangible plant [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	0 years
Utility plant, gross	$ 140	140
Utility plant in service-Water [Member] | Source of supply plant [Member]
Summary of utility plant comprises [Abstract]
Utility plant, gross	$ 22,611	22,320
Utility plant in service-Water [Member] | Source of supply plant [Member] | Minimum [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	45 years
Utility plant in service-Water [Member] | Source of supply plant [Member] | Maximum [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	85 years
Utility plant in service-Water [Member] | Pumping and water treatment plant [Member]
Summary of utility plant comprises [Abstract]
Utility plant, gross	$ 90,795	85,399
Utility plant in service-Water [Member] | Pumping and water treatment plant [Member] | Minimum [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	8 years
Utility plant in service-Water [Member] | Pumping and water treatment plant [Member] | Maximum [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	62 years
Utility plant in service-Water [Member] | General plant [Member]
Summary of utility plant comprises [Abstract]
Utility plant, gross	$ 61,512	60,536
Utility plant in service-Water [Member] | General plant [Member] | Minimum [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	5 years
Utility plant in service-Water [Member] | General plant [Member] | Maximum [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	31 years
Utility plant in service-Wastewater [Member] | General plant [Member]
Summary of utility plant comprises [Abstract]
Utility plant, gross	$ 1,223	1,206
Utility plant in service-Wastewater [Member] | General plant [Member] | Minimum [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	5 years
Utility plant in service-Wastewater [Member] | General plant [Member] | Maximum [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	31 years
Utility plant in service-Wastewater [Member] | Treatment and Disposal Plant [Member]
Summary of utility plant comprises [Abstract]
Utility plant, gross	$ 19,315	17,635
Utility plant in service-Wastewater [Member] | Treatment and Disposal Plant [Member] | Minimum [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	21 years
Utility plant in service-Wastewater [Member] | Treatment and Disposal Plant [Member] | Maximum [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	81 years
Utility plant in service-Wastewater [Member] | Collection Mains & Lift Stations [Member]
Summary of utility plant comprises [Abstract]
Estimated useful life	81 years
Utility plant, gross	$ 19,348	$ 14,242
Artesian Water [Member]
Utility Plant [Abstract]
Capitalized rate of AFUDC	7.10%	7.40%	7.70%
Artesian Wastewater [Member]
Utility Plant [Abstract]
Capitalized rate of AFUDC	7.10%	5.90%	3.60%