Benefit Plans - Narrative (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2023 USD ($)	Sep. 30, 2023 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Employer plan contributions	$ 3,567	$ 7,627
Maximum
Defined Benefit Plan Disclosure [Line Items]
Estimated employer contributions for the remainder of fiscal year	$ 8,653	$ 8,653
CTWS Employees
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase		1.50%

Amount of contribution expected to be received by defined benefit plan from employer in remainder of current fiscal year. Excludes contribution previously paid by employer in current fiscal year.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480482/715-20-55-18

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-6

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