Annual report pursuant to Section 13 and 15(d)

Mineral Properties - rollforward (Details)

v3.3.1.900
Mineral Properties - rollforward (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Balance at beginning of period $ 52,750 $ 52,702  
Acquisition costs   50  
Increase in reclamation costs 2,101 5,669  
Reporting exchange rate adjustment   (6)  
Property write-offs   (483) $ (1,430)
Amortization (4,241) (5,182)  
Balance at end of period 50,610 52,750 52,702
Canadian Properties [Member]      
Balance at beginning of period   489  
Reporting exchange rate adjustment   (6)  
Property write-offs   (483)  
Balance at end of period     489
Lost Creek Property      
Balance at beginning of period 18,512 23,686  
Acquisition costs   8  
Increase in reclamation costs 2,391    
Amortization (4,241) (5,182)  
Balance at end of period 16,662 18,512 23,686
Other Us Properties [Member]      
Balance at beginning of period 13,210 13,210  
Balance at end of period 13,210 13,210 13,210
Path Finder Mines [Member]      
Balance at beginning of period 21,028 15,317  
Acquisition costs   42  
Increase in reclamation costs (290) 5,669  
Balance at end of period $ 20,738 $ 21,028 $ 15,317