Accrued Closure Costs and ARO - Schedule of Change in Asset Retirement Obligation (Details) - USD ($) $ in Thousands |
3 Months Ended | 12 Months Ended | |||||
|---|---|---|---|---|---|---|---|
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Dec. 31, 2017 |
Sep. 30, 2017 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Asset Retirement Obligation Disclosure [Abstract] | |||||||
| Balance at beginning | $ 8,395 | $ 7,315 | |||||
| Accretion expense | 325 | 460 | |||||
| Spending | (5,293) | (2,037) | |||||
| Adjustment to closure liability | $ 1,015 | $ 1,093 | $ 1,215 | $ 850 | $ 550 | 3,323 | 2,657 |
| Balance at end | $ 6,750 | $ 8,395 | $ 6,750 | $ 8,395 | |||
| X | ||||||||||
- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of increase (decrease) in asset retirement obligations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|