Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Name:	us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Summary of Significant Accounting Policies - Cash and Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 23, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Public Utilities, General Disclosures [Line Items]
Long-term borrowings held as restricted cash		$ 0	$ 4,000	$ 5,000
Cash		10,908	5,269
Restricted cash		1,211	$ 4,000
Maine Water Company
Public Utilities, General Disclosures [Line Items]
Long-term borrowings held as restricted cash	$ 4
Cash		2,789
Restricted cash		$ 1,211