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COMMITTMENTS AND CONTINGENCIES (Narrative) (Details) |  |  |  | 3 Months Ended | 6 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | --- | ---
Jul. 29, 2016 complaint defendant | Feb. 09, 2016 complaint defendant | Mar. 11, 1997 | Sep. 30, 2018 USD ($) well | Jul. 29, 2016 complaint | Sep. 30, 2018 USD ($) well | Sep. 30, 2017 USD ($) | Dec. 31, 1997 USD ($) well
Commitments [Line Items] |  |  |  |  |  |  |  |
Plugging and abandonment trust on the WCBB properties |  |  |  | $ 3,100,000 |  | $ 3,100,000 |  |
Number of claims filed (in claims) | complaint |  |  |  |  | 2 |  |  |
Judicial District Court for the Parish of Cameron |  |  |  |  |  |  |  |
Commitments [Line Items] |  |  |  |  |  |  |  |
Number of claims filed (in claims) | complaint |  | 1 |  |  |  |  |  |
Number of defendants (in defendants) | defendant |  | 26 |  |  |  |  |  |
Judicial District Court for the Parish of Vermillion |  |  |  |  |  |  |  |
Commitments [Line Items] |  |  |  |  |  |  |  |
Number of claims filed (in claims) | complaint | 1 |  |  |  |  |  |  |
Number of defendants (in defendants) | defendant | 40 |  |  |  |  |  |  |
Purchase commitment |  |  |  |  |  |  |  |
Commitments [Line Items] |  |  |  |  |  |  |  |
Future minimum commitments |  |  |  | 154,200,000 |  | 154,200,000 |  |
Transportation commitment |  |  |  |  |  |  |  |
Commitments [Line Items] |  |  |  |  |  |  |  |
Firm transportation contracted with third parties |  |  |  | 3,566,330,000 |  | 3,566,330,000 |  |
Future minimum commitments |  |  |  | 62,012,000 |  | 62,012,000 |  |
Loss on long-term purchase commitment | Muskie Proppant LLC |  |  |  |  |  |  |  |
Commitments [Line Items] |  |  |  |  |  |  |  |
Non-utilization fees, accrued damages year to date |  |  |  | $ 1,300,000 |  | $ 1,500,000 | $ 0 |
Minimum |  |  |  |  |  |  |  |
Commitments [Line Items] |  |  |  |  |  |  |  |
Operating lease, term (in years) |  |  |  | 1 year |  | 1 year |  |
WCBB |  |  |  |  |  |  |  |
Commitments [Line Items] |  |  |  |  |  |  |  |
Remaining interest in oil and gas property acquisition, percent |  |  |  |  |  |  |  | 50.00%
Payments of seller's obligation to contribute |  |  |  |  |  |  |  | $ 18,000
Minimum number of wells to be plugged (in wells) | well |  |  |  |  |  |  |  | 20
Tenure of minimum wells to be plugged (in years) |  |  | 20 years |  |  |  |  |
Number of wells plugged (in wells) | well |  |  |  | 555 |  | 555 |  |

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