XML 259 R198.htm IDEA: XBRL DOCUMENT v3.10.0.1
Number of Crude Oil and Natural Gas Wells Drilled and Completed (Detail) - Wells
 12 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2016
Disclosure of net productive wells and dry wells drilled [Line Items]      
Net exploratory wells, Productive 1 3 1
Net exploratory wells, Dry 1 2  
Net exploratory wells, Total 2 5 1
Net development wells, Productive 85 81 140
Net development wells, Dry 1   2
Net development wells, Total 86 81 142
Total 88 86 143
Australia [member]      
Disclosure of net productive wells and dry wells drilled [Line Items]      
Net development wells, Productive 1   2
Net development wells, Total 1   2
Total 1   2
United States [member]      
Disclosure of net productive wells and dry wells drilled [Line Items]      
Net exploratory wells, Productive 1   1
Net exploratory wells, Dry 1    
Net exploratory wells, Total 2   1
Net development wells, Productive 84 80 137
Net development wells, Dry 1   2
Net development wells, Total 85 80 139
Total 87 80 140
Other countries [member]      
Disclosure of net productive wells and dry wells drilled [Line Items]      
Net exploratory wells, Productive   3  
Net exploratory wells, Dry   2  
Net exploratory wells, Total   5  
Net development wells, Productive   1 1
Net development wells, Total   1 1
Total   6 1