XML 428 R150.htm IDEA: XBRL DOCUMENT v3.19.1
Equity-Accounted Investees - Additional Information (Detail) - USD ($)
 12 Months Ended
Dec. 06, 2017
Aug. 22, 2016
Dec. 31, 2018
Dec. 31, 2017
Oct. 19, 2018
Dec. 31, 2010
Disclosure of equity-accounted investees [line items]            
Carrying value write down due to loss incurred by the entity     $ 225,100,000 $ 171,300,000    
Rusoro Mining Limited [member]            
Disclosure of equity-accounted investees [line items]            
Carrying value write down due to loss incurred by the entity           $ 0
Fair value of investment based on quoted market price     13,400,000 7,700,000    
Unrecognised share of profits     2,600,000 2,000,000    
Cumulative unrecognised share of losses     $ 198,600,000 $ 196,000,000    
Pre and post award   $ 967,800,000        
Excess of pre and post award   $ 1,200,000,000        
Arbitration settlement $ 1,300,000,000          
Accrued interest percentage     9.00%      
Total settlement agreement amount         $ 1,280,000,000