XML 167 R148.htm IDEA: XBRL DOCUMENT v3.8.0.1
Share based compensation - Fair Value Assumptions (Details)
12 Months Ended
Dec. 31, 2017
USD ($)
year
Dec. 31, 2016
USD ($)
year
Disclosure of terms and conditions of share-based payment arrangement [line items]    
Dividend yield (%) 4.00% 4.00%
Weighted average exercise price (in USD per share) | $ $ 0.65 $ 0.67
Minimum    
Disclosure of terms and conditions of share-based payment arrangement [line items]    
Expected volatility range (%) 26.81% 29.73%
Risk-free interest rate (%) 1.00% 0.36%
Expected life of share options range (years) 0.50 1
Maximum    
Disclosure of terms and conditions of share-based payment arrangement [line items]    
Expected volatility range (%) 35.81% 38.73%
Risk-free interest rate (%) 2.01% 1.05%
Expected life of share options range (years) 7.36 3.5