XML 102 R88.htm IDEA: XBRL DOCUMENT v3.10.0.1
Obligations Under Guarantees (Details)
$ in Millions
Jun. 30, 2018
USD ($)
Surety Bonds  
Loss Contingencies  
Surety bonds outstanding $ 28.6
Reclamation Bonds  
Loss Contingencies  
Bonds related to reclamation requirements $ 25.6