Property and Equipment - Narrative (Details) |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2017
USD ($)
usd_per_mcf
|
Dec. 31, 2016
USD ($)
usd_per_mcf
|
Dec. 31, 2015
USD ($)
usd_per_mcf
|
|
| Property, Plant and Equipment [Line Items] | |||
| Impairment of oil and natural gas properties | $ 0 | $ 715,495,000 | $ 1,440,418,000 |
| Cumulative capitalization of general and administrative costs incurred and capitalized to the full cost pool | 165,600,000 | 129,900,000 | |
| Capitalized general and administrative costs | 35,700,000 | 29,300,000 | $ 27,900,000 |
| Capitalized costs of oil and natural gas properties excluded from amortization | $ 2,912,974,000 | $ 1,580,305,000 | |
| Depletion per Mcf of gas equivalent (usd per Mcfe) | usd_per_mcf | 0.90 | 0.92 | 1.68 |
| Minimum | |||
| Property, Plant and Equipment [Line Items] | |||
| Expected number of years amortization will commence | 3 years | ||
| Maximum | |||
| Property, Plant and Equipment [Line Items] | |||
| Expected number of years amortization will commence | 5 years | ||