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Goodwill and Intangible Assets - Goodwill (Details) - U.S. Water Services [Member] - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017
Goodwill [Roll Forward] |  |  |
Beginning Balance |  | $ 148.3 | $ 131.2
Acquired Goodwill | [1] |  | 16.9
Other Adjustments | [2] | 0.2 | 0.2
Ending Balance |  | $ 148.5 | $ 148.3
[1] | See Note 6. Acquisitions.
[2] | Finalization of purchase price accounting for U.S. Water Services’ acquisition of WEST was completed in 2017 and acquisition of Tonka Water was completed in 2018 resulting in adjustments in those periods to the goodwill recorded at the time of acquisition.

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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266 + Details
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