Annual report pursuant to Section 13 and 15(d)

Mineral Properties (Details)

v3.3.1.900
Mineral Properties (Details)
$ in Thousands, shares in Millions
 1 Months Ended 12 Months Ended
Dec. 31, 2013
USD ($)
Apr. 30, 2013
USD ($)
item
shares
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Dec. 31, 2005
USD ($)
Dec. 31, 2015
Stock Issued During Period Value Issued For Royalty Interest       $ 763    
Write-off of mineral properties     $ 483 1,430    
Lost Creek Property            
Royalty (as a percent)   1.67%        
Number Of Mining Claims | item   20        
Stock Issued During Period Shares Issued For Royalty Interest | shares   1        
Stock Issued During Period Value Issued For Royalty Interest   $ 763        
Mining Claims In LC North LC East or LC West            
Royalty (as a percent)           0.00%
Mustang Project            
Write-off of mineral properties       $ 1,168    
Nfu Wyoming LLC | Lost Creek Property            
Percentage of asset acquired         100.00%  
Aggregate consideration         $ 20,000  
Pathfinder Mines Corporation            
Aggregate consideration $ 6,700          
Royalty (as a percent) 5.00%     5.00%    
Estimated asset reclamation obligation $ 5,700     $ 5,700    
Deferred tax liabilities 3,300     3,300    
Mineral properties $ 15,300     $ 15,300