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Benefit Plans - Narrative (Details) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 USD ($) | Sep. 30, 2021 USD ($)
Defined Benefit Plan Disclosure [Line Items] |  |
Estimated employer contributions for the current fiscal year | $ 9,043 | $ 9,043
Employer plan contributions | $ 3,517 | $ 4,997
CTWS Employees |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Rate of compensation increase |  | 1.50%

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- Definition Defined Benefit Plan, Rate of Compensation Increase + References No definition available. + Details
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- Definition Amount of contributions received and expected to be received by defined benefit plan from employer in current fiscal year. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e2709-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=123450688&loc=d3e4587-114921 + Details
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