XML 156 R85.htm IDEA: XBRL DOCUMENT v3.19.1
Significant accounting policies, estimates and judgements (Details)
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
U.S. Dollar [Member]      
Average foreign exchange rate 1.18 1.13 1.11
Closing foreign exchange rate 1.15 1.20 1.05
Pound Sterling [Member]      
Average foreign exchange rate 0.88 0.88 0.82
Closing foreign exchange rate 0.89 0.88 0.86
Norwegian Krone [Member]      
Average foreign exchange rate 9.60 9.33 9.29
Closing foreign exchange rate 9.94 9.83 9.09
Australian Dollar [Member]      
Average foreign exchange rate 1.58 1.47 1.49
Closing foreign exchange rate 1.62 1.53 1.46