Commitments (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($) ServiceLine	Dec. 31, 2019 USD ($)
Company-Owned Lead Service Lines [Member]
Commitments [Abstract]
Term to replace all remaining company-owned lead service lines	4 years
Costs incurred to replace company-owned lead service lines	$ 2,723	$ 2,713
Customer-Owned Lead Service Lines [Member]
Commitments [Abstract]
Number of lead customer-owned service lines to be replaced annually | ServiceLine	400
Term of tariff modification to replace customer-owned lead service lines	9 years
Recovery period of regulatory asset	4 years
Costs incurred to replace customer-owned lead service lines	$ 1,113	$ 1,000
Costs to be incurred to replace customer-owned lead service lines	$ 1,300