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20. Employees benefits (Details 11)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
SummaryOfEmployeeBenefitsLineItems [Line Items]      
Discount rate 5.35% 5.74% 7.23%
Inflation rate 3.96% 4.87% 6.49%
Future salary increase 9.52% 10.89% 14.19%
Mortality table AT-2000 AT-2000 AT-2000
Unfunded plan      
SummaryOfEmployeeBenefitsLineItems [Line Items]      
Discount rate 5.30% 5.71% 7.25%
Inflation rate 3.96% 4.87% 6.49%
Future salary increase 6.04% 6.97% 8.62%
Mortality table AT-2000 AT-2000 AT-2000