XML 50 R103.htm IDEA: XBRL DOCUMENT v3.20.1
Income and other taxes - Unused tax losses (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Tax effect $ (6,945) $ (31,325)
Unused tax losses    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Gross amount 1,243,496  
Tax effect 286,004  
Expire | Unused tax losses    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Gross amount 1,000,762  
Tax effect 230,175  
Losses generated in 2015 (expires 2035) | Unused tax losses    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Gross amount 333,240  
Tax effect 76,645  
Losses generated in 2016 (expires 2036) | Unused tax losses    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Gross amount 432,581  
Tax effect 99,494  
Losses generated in 2017 (expires 2037) | Unused tax losses    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Gross amount 234,941  
Tax effect 54,036  
Losses generated in 2019 | Unused tax losses    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Gross amount 242,734  
Tax effect $ 55,829