| 
           Mineral Properties (Details) (USD $) 
        In Thousands, unless otherwise specified  | 
        12 Months Ended | 1 Months Ended | 12 Months Ended | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 
           Dec. 31, 2013 
         | 
        
           Dec. 31, 2012 
         | 
        
           Dec. 31, 2011 
         | 
        
           Dec. 31, 2013
 
          Lost Creek Property [Member] 
         | 
        
           Dec. 31, 2012
 
          Lost Creek Property [Member] 
         | 
        
           Jun. 30, 2013
 
          Other Us Properties [Member] 
         | 
        
           Dec. 31, 2013
 
          Other Us Properties [Member] 
         | 
        
           Dec. 31, 2012
 
          Other Us Properties [Member] 
         | 
        
           Dec. 31, 2013
 
          Canadian Properties [Member] 
         | 
        
           Dec. 31, 2012
 
          Canadian Properties [Member] 
         | 
        
           Dec. 31, 2013
 
          Path Finder Mines [Member] 
         | 
        
           Dec. 31, 2012
 
          Path Finder Mines [Member] 
         | 
      ||||||||||||||||
| Balance | $ 33,501 | [1] | $ 31,480 | [1] | $ 15,505 | [1] | $ 13,917 | [1] | $ 17,471 | [1] | $ 17,050 | [1] | $ 525 | [1] | $ 513 | [1] | $ 0 | [1] | $ 0 | [1] | |||||||
| Property acquired in asset exchange | 971 | [1] | 971 | [1] | 0 | [1] | 0 | [1] | 0 | [1] | |||||||||||||||||
| Capitalized Reclamation Costs | 10,276 | 320 | [1] | 10,276 | 292 | [1] | 0 | 28 | [1] | 0 | 0 | [1] | 0 | 0 | [1] | ||||||||||||
| Royalty acquired for common stock | 783 | 783 | 0 | 0 | 0 | ||||||||||||||||||||||
| Property write-offs | (1,430) | 0 | 0 | 0 | (261) | (1,430) | 0 | 0 | |||||||||||||||||||
| Functional Currency exchange rate adjustment | (5,274) | [2] | (2,443) | [2] | (2,831) | [2] | 0 | [2] | |||||||||||||||||||
| Reporting exchange rate adjustment | (36) | [2] | 730 | [1] | 0 | [2] | 325 | [1] | 0 | [2] | 393 | [1] | (36) | [2] | 12 | [1] | 0 | [2] | 0 | [1] | |||||||
| Amortization | (435) | (435) | 0 | 0 | 0 | ||||||||||||||||||||||
| Purchase of Pathfinder Mines | 15,317 | 0 | 0 | 0 | 15,317 | ||||||||||||||||||||||
| Balance | $ 52,702 | $ 33,501 | [1] | $ 31,480 | [1] | $ 23,686 | $ 15,505 | [1] | $ 13,210 | $ 17,471 | [1] | $ 489 | $ 525 | [1] | $ 15,317 | $ 0 | [1] | ||||||||||
          
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