Fair Value Measurements (Quantitative Information About Unobservable Inputs Used In Level 3) (Details) - WTI Options [Member] - Option Model [Member] |
3 Months Ended | 12 Months Ended |
|---|---|---|
Mar. 31, 2017 |
Dec. 31, 2016 |
|
| Maximum [Member] | ||
| Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ||
| Fair Value Inputs Commodity Price Volatility | 56.00% | 64.00% |
| Minimum [Member] | ||
| Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] | ||
| Fair Value Inputs Commodity Price Volatility | 18.00% | 18.00% |