XML 69 R33.htm IDEA: XBRL DOCUMENT v3.8.0.1
Other Investments, Summary (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Schedule of Cost-method Investments [Line Items]      
Gain/(loss) during the period $ (1,248) $ 3,196 $ (1,593)
Midas Gold Shares [Member]      
Schedule of Cost-method Investments [Line Items]      
Fair value at beginning of period 4,994 1,798  
Gain/(loss) during the period (1,248) 3,196  
Fair value at end of period $ 3,746 $ 4,994 $ 1,798
Midas Gold Shares held at end of the period 7,802,615 7,802,615