|   |    |    12-31-2017   |    |    12-31-2016   |    |  
|   |    |    ThU.S.$   |    |    ThU.S.$   |    |  
|   Current   |    |    5,730   |    |    5,244   |    |  
|   Non-current   |    |    66,033   |    |    60,084   |    |  
|   Total   |    |    71,763   |    |    65,328   |    |  
|   |    |    12-31-2017   |    |    12-31-2016   |    |  
|    Reconciliation of the present value of severance indemnities obligations   |    |    ThU.S.$   |    |    ThU.S.$   |    |  
|   Opening balance   |    |    65,328   |    |    56,433   |    |  
|   Current service cost   |    |    5,583   |    |    5,334   |    |  
|   Interest cost   |    |    3,208   |    |    2,957   |    |  
|   (Gains) losses from changes in actuarial assumptions   |    |    (3,711)   |    |    2,083   |    |  
|   Actuarial gains and losses arising from experience   |    |    1,212   |    |    3,503   |    |  
|   Benefits paid   |    |    (5,654)   |    |    (7,871)   |    |  
|   Increase (decrease) for foreign currency exchange rates changes   |    |    5,792   |    |    2,889   |    |  
|   Closing balance   |    |    71,763   |    |    65,328   |    |