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COMMITMENTS AND CONTINGENT LIABILITIES - LEGAL PROCEEDINGS (Details) $ in Thousands | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jul. 31, 2018 USD ($) | Dec. 31, 2018 USD ($) site | Sep. 30, 2018 USD ($)
Site Contingency [Line Items] |  |  |
Number of MGP sites | site |  | 5 |
Recovery from third party of environmental remediation cost, period |  | 7 years |
Regulatory assets |  | $ 370,024 | $ 368,592
Manufactured gas plant remediation |  | 129,556 | 130,800
Minimum |  |  |
Site Contingency [Line Items] |  |  |
Product liability contingency, loss exposure in excess of accrual, best estimate |  | 117,700 |
Maximum |  |  |
Site Contingency [Line Items] |  |  |
Product liability contingency, loss exposure in excess of accrual, best estimate |  | 204,100 |
Expended, net of recoveries |  |  |
Site Contingency [Line Items] |  |  |
Regulatory assets |  | $ 32,764 | 33,017
RAC |  |  |
Site Contingency [Line Items] |  |  |
Public utilities, approved rate, amount | $ 9,400 |  | $ 7,000

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