Fair Value Measurement - Financial Instruments Carried at Fair Value by Consolidated Balance Sheet Caption and by Valuation Hierarchy (Details) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Valuation Hierarchy | ||
| Current assets | $ 24,100 | $ 124,207 |
| Long-term assets | 34,744 | 93,302 |
| Current liabilities | 14,650 | 11 |
| Long-term liabilities | 1,209 | |
| Recurring | Commodity Derivative Instruments | ||
| Valuation Hierarchy | ||
| Current assets | 24,100 | 124,207 |
| Long-term assets | 34,744 | 93,302 |
| Current liabilities | 14,650 | 11 |
| Long-term liabilities | 1,209 | |
| Recurring | Level 2 | Commodity Derivative Instruments | ||
| Valuation Hierarchy | ||
| Current assets | 24,100 | 122,779 |
| Long-term assets | 36,384 | 93,302 |
| Current liabilities | 13,636 | 11 |
| Long-term liabilities | 892 | |
| Recurring | Level 3 | Commodity Derivative Instruments | ||
| Valuation Hierarchy | ||
| Current assets | $ 1,428 | |
| Long-term assets | (1,640) | |
| Current liabilities | 1,014 | |
| Long-term liabilities | $ 317 |