BUSINESS SEGMENT INFORMATION - Segment Reporting Information, by Segment (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2025		Jun. 30, 2024		Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
BUSINESS SEGMENT INFORMATION [Abstract]
Revenues		$ 28,549		$ 27,416		$ 54,435	$ 51,960
Depreciation and Amortization		3,414		3,425		6,771	6,889
Property and other taxes		1,603		1,524		3,288	3,130
Operating Income		7,855		7,198		13,400	11,917
Assets		819,296				819,296		$ 798,623
Operating Segments [Member]
BUSINESS SEGMENT INFORMATION [Abstract]
Operating Income		7,301		6,907		12,362	11,265
Intersegment Eliminations [Member]
BUSINESS SEGMENT INFORMATION [Abstract]
Revenues		(65)		(58)		(128)	(118)
Regulated Utility [Member] | Operating Segments [Member]
BUSINESS SEGMENT INFORMATION [Abstract]
Revenues		26,723		25,789		50,768	48,630
Payroll and Benefits	[2]	6,183	[1]	6,254	[1]	12,394	12,612
Supply and Delivery	[2],[3]	4,069		3,764		7,521	7,127
Administrative	[2],[4]	2,318		2,220		5,043	4,515
Depreciation and Amortization	[2]	3,401		3,412		6,745	6,863
Income Taxes	[2]	1,866		1,725		3,450	3,151
Property and other taxes	[2]	1,585		1,507		3,253	3,097
Operating Income	[2]	7,301		6,907		12,362	11,265
Assets		815,090				815,090		793,118
Reportable Segment, Aggregation before Other Operating Segment [Member]
BUSINESS SEGMENT INFORMATION [Abstract]
Revenues		28,549		27,416		54,435	51,960
Reportable Segment, Aggregation before Other Operating Segment [Member] | Operating Segments [Member]
BUSINESS SEGMENT INFORMATION [Abstract]
Revenues		26,723		25,789		50,768	48,630
Operating Income	[2]	7,301		6,907		12,362	11,265
Assets		815,090				815,090		793,118
Other Operating Segment [Member] | Operating Segments [Member]
BUSINESS SEGMENT INFORMATION [Abstract]
Revenues	[5]	1,891		1,685		3,795	3,448
Operating Income	[5]	554		$ 291		1,038	$ 652
Assets		$ 4,206				$ 4,206		$ 5,505

[1] Payroll and benefits: – This category does not include amounts capitalized on the Condensed Consolidated Balance Sheet

[2] Significant expense categories: – The significant expense categories and amounts align with the segment-level information that is regularly provided to the CODM – Inter-segment expenses related to leased space provided by one non-utility business, calculated on the lower of cost or market method, are included in the amounts shown

[3] Supply and Delivery: – This category includes purchased power, purchased water, chemicals, infrastructure maintenance and repair costs, and wastewater disposal fees

[4] Administration expense: – This category includes computer systems maintenance and subscription fees, audit and legal fees, insurance, customer billing, and other general and administrative expenses

[5] Other revenues and other profit: – Revenue and profit from segments below the quantitative thresholds are attributable to four non-utility businesses of the Company – These businesses are primarily comprised of: Service Line Protection Plan services for water, sewer and internal plumbing; design, construction and engineering services; contract services for the operation and maintenance of water and wastewater systems in Delaware and Maryland; and leased space to the Regulated Utility Segment – These non-utility businesses do not individually or in the aggregate meet the quantitative thresholds for determining reportable segments – Certain corporate costs have been allocated from the regulated utility segment to the non-utility businesses and are included in the other profit amounts shown