| SourceName | Taxonomy Technical Improvement | http://fasb.org/srt/role/changeNote/changeNote |
| TaxonomyVersion | 2019 | http://fasb.org/srt/role/changeNote/changeNote |
| ChangeDate | 2018-10 | http://fasb.org/srt/role/changeNote/changeNote |
| ModifiedLabels | true | http://fasb.org/srt/role/changeNote/changeNote |
| ModifiedDocumentation | true | http://fasb.org/srt/role/changeNote/changeNote |
| PreviousDocumentation | The number of productive exploratory wells drilled in the geographic area. A productive well is a well that is not a dry well. The number of wells drilled refers to the number of wells (holes) completed at any time during the fiscal years, regardless when drilling was initiated. | http://fasb.org/srt/role/changeNote/changeNote |