XML 78 R47.htm IDEA: XBRL DOCUMENT v3.19.1
Inventory (Narrative) (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2018
USD ($)
oz
Dec. 31, 2017
USD ($)
Inventory [Line Items]    
Long-term inventory $ 30.0 $ 68.7
Mining and processing costs, inventories 393.1 323.3
Amortization costs, Inventories 166.6 $ 125.6
El Chanate [Member]    
Inventory [Line Items]    
Inventory write-down $ 64.0  
Unrecoverable Ounces | oz 51,900  
Impairment loss $ 64.0  
Impairment loss net of tax 49.9  
El Chanate [Member] | Mining [Member]    
Inventory [Line Items]    
Inventory write-down 62.5  
El Chanate [Member] | Amortization [Member]    
Inventory [Line Items]    
Inventory write-down $ 1.5