Regulatory Decision and Related Accounting and Policy Changes - Additional Information (Details) $ in Thousands		12 Months Ended
	Jul. 09, 2012 utility	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2005 USD ($)
Public Utilities, General Disclosures [Line Items]
Number of utilities to adjust revenue requirement | utility	7
Requested collective rate of increase over revenue	28.00%
Approved collective revenue increase		$ 3,600
Adopted rate of return on common equity		9.50%
Percentage of hook up fee liability to be recorded on ICFA receipts		70.00%
Revenues		$ 35,471	$ 35,515		$ 4,900
Percentage of deferred revenue to be recorded on ICFA receipts		30.00%
ICFA fee as deferred revenue		The Company is responsible for assuring the full HUF value is paid from ICFA proceeds, and recorded in its full amount, even if it results in recording less than 30% of the ICFA fee as deferred revenue.
Deferred revenue - ICFA		$ 17,372	17,358
Percentage of regulatory liability		70.00%
Percentage reversal of regulatory liability				30.00%
Reversal of regulatory liability				$ 3,400
Regulatory liability		$ 8,803	8,851
Regulatory asset		1,715	$ 1,793
ICFA
Public Utilities, General Disclosures [Line Items]
Deferred revenue - ICFA		17,400
Regulatory liability		$ 7,900