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Suspended Well Costs (Tables) | 12 Months Ended
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Dec. 31, 2017
Suspended Well Costs [Abstract] |
Net changes in capitalized exploratory well costs [Table Text Block] | The following table reflects the net changes in capitalized exploratory well costs during 2017, 2016, and 2015. The table does not include amounts that were capitalized and either subsequently expensed or reclassified to producing well costs in the same year:
| For the Years Ended December 31,
| 2017 |  | 2016 |  | 2015
| (in thousands)
Beginning balance | $ | 19,846 |  |  | $ | 11,952 |  |  | $ | 43,589 |
Additions to capitalized exploratory well costs pending the determination of proved reserves | 49,446 |  |  | 19,846 |  |  | 11,952 |
Divestitures | — |  |  | — |  |  | (809 | )
Reclassifications to wells, facilities, and equipment based on the determination of proved reserves | (19,846 | ) |  | (11,952 | ) |  | (18,485 | )
Capitalized exploratory well costs charged to expense | — |  |  | — |  |  | (24,295 | )
Ending balance | $ | 49,446 |  |  | $ | 19,846 |  |  | $ | 11,952 |

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- Definition Tabular disclosure of the change in capitalized exploratory costs during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 1B -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=68064819&loc=SL6806780-109447 + Details
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