ASSET RETIREMENT OBLIGATION (Narrative) (Details) - USD ($) $ in Millions |
Sep. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Asset Retirement Obligation Disclosure [Abstract] | ||
| Credit adjusted risk-free rates to discount abandonment liabilities, low end of range (as a percent) | 6.90% | |
| Credit adjusted risk-free rates to discount abandonment liabilities, high end of range (as a percent) | 8.50% | |
| Asset retirement obligation, current | $ 0.0 | |
| Undiscounted amount of asset retirement obligation | $ 58.4 |