Acquisitions (Narrative) (Details) $ in Thousands	1 Months Ended
	Dec. 31, 2023 USD ($) customer	Sep. 30, 2023 USD ($) customer	Jul. 31, 2023 USD ($) customer	Jun. 30, 2023 USD ($) customer	Apr. 30, 2023 USD ($) customer	Mar. 31, 2023 USD ($) customer	Aug. 31, 2022 USD ($) customer	Oct. 31, 2021 USD ($) customer	Sep. 30, 2019 USD ($) item customer
Shenandoah Borough [Member]
Business Acquisition [Line Items]
Number of customers | customer			2,900
Total purchase price | $			$ 12,291
La Rue [Member]
Business Acquisition [Line Items]
Number of customers | customer			300
Total purchase price | $			$ 2,253
Southern Oaks Water System [Member]
Business Acquisition [Line Items]
Number of customers | customer			800
Total purchase price | $			$ 3,321
Village of Frankfort [Member]
Business Acquisition [Line Items]
Number of customers | customer			1,500
Total purchase price | $			$ 1,424
Union Rome [Member]
Business Acquisition [Line Items]
Number of customers | customer				4,300
Total purchase price | $				$ 25,547
North Heidelberg Sewer Company [Member]
Business Acquisition [Line Items]
Number of customers | customer						300
Total purchase price | $						$ 136
Delaware [Member] | Wastewater Utility System [Member]
Business Acquisition [Line Items]
Number of customers | customer									16,000
Total purchase price | $									$ 276,500
Retail customers | customer									198,000
Number of municipalities | item									42
East Whiteland Township [Member] | Water And Wastewater Utility Systems [Member]
Business Acquisition [Line Items]
Number of customers | customer							4,018
Total purchase price | $							$ 54,374
Glenview, Illinois [Member] | Water And Wastewater Utility Systems [Member]
Business Acquisition [Line Items]
Number of customers | customer				2
Total purchase price | $				$ 50
Greenville, Pennsylvania [Member] | Water And Wastewater Utility Systems [Member]
Business Acquisition [Line Items]
Number of customers | customer		3,000			2,300
Total purchase price | $		$ 18,000			$ 18,000
Beaver Falls Pennsylvania [Member] | Water And Wastewater Utility Systems [Member]
Business Acquisition [Line Items]
Number of customers | customer								7,600
Total purchase price | $								$ 41,250
North Versailles Pennsylvania [Member] | Water And Wastewater Utility Systems [Member]
Business Acquisition [Line Items]
Number of customers | customer	4,400
North Versailles Pennsylvania [Member] | Water And Wastewater Utility Systems [Member] | Minimum [Member]
Business Acquisition [Line Items]
Total purchase price | $	$ 25,000
North Versailles Pennsylvania [Member] | Water And Wastewater Utility Systems [Member] | Maximum [Member]
Business Acquisition [Line Items]
Total purchase price | $	$ 30,000