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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - RECEIVABLE BY SUBSIDIARY (Details) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Sep. 30, 2017 | Sep. 30, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Establishment of allowance for doubtful accounts, customer account balances, days outstanding (more than) | 60 days |
Billed | $ 196,467 | $ 142,658
Receivable by subsidiary percentage | 100.00% | 100.00%
Unbilled revenues | $ 7,202 | $ 5,744
Energy Services |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Billed | $ 150,322 | $ 102,884
Receivable by subsidiary percentage | 77.00% | 72.00%
Natural Gas Distribution |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Billed | $ 37,432 | $ 30,951
Receivable by subsidiary percentage | 19.00% | 22.00%
Clean Energy Ventures |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Billed | $ 2,655 | $ 1,807
Receivable by subsidiary percentage | 1.00% | 1.00%
NJRHS and other |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Billed | $ 6,058 | $ 7,016
Receivable by subsidiary percentage | 3.00% | 5.00%

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- Definition Amounts due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer) for goods or services (including trade receivables) that have been delivered or sold in the normal course of business. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(3)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(5)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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