Subsequent Event (Details) - Subsequent Event $ in Millions	Oct. 08, 2019 USD ($)
Subsequent Event [Line Items]
Current projects amount	$ 200.0
Advice letter authorizations	$ 148.0
Water main replacement rate	0.76%
Minimum
Subsequent Event [Line Items]
New projects amount	$ 609.0
Capital investments	809.0
Maximum
Subsequent Event [Line Items]
New projects amount	628.0
Capital investments	$ 828.0