Asset Retirement Obligations (Details) - USD ($) |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Change in estimated liability | $ 448,000 | $ (534,000) |
| Lost Creek Property | ||
| Estimated Future Cash Undiscounted Amount | 15,600,000 | |
| Change in estimated liability | $ 613,000 | 338,000 |
| Lost Creek Property | Minimum | ||
| Discount Rate Of Asset Retirement Obligations | 0.10% | |
| Lost Creek Property | Maximum | ||
| Discount Rate Of Asset Retirement Obligations | 3.20% | |
| Path Finder Mines [Member] | ||
| Estimated Future Cash Undiscounted Amount | $ 11,400,000 | |
| Change in estimated liability | $ (165,000) | $ (872,000) |
| Path Finder Mines [Member] | Minimum | ||
| Discount Rate Of Asset Retirement Obligations | 2.16% | |
| Path Finder Mines [Member] | Maximum | ||
| Discount Rate Of Asset Retirement Obligations | 3.00% | |
| X | ||||||||||
- Definition Discount Rate Of Asset Retirement Obligations No definition available.
|
| X | ||||||||||
- Definition Amount of estimated future cash undiscounted amount. No definition available.
|
| X | ||||||||||
- Definition Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|