Other Current Assets - Schedule of Other Current Assets (Detail) - USD ($) $ in Thousands |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Statement of Financial Position [Abstract] | ||
| Margin deposits with brokers | $ 37,089 | $ 22,779 |
| Deposits | 5,758 | 0 |
| Natural gas transportation, current portion | 2,716 | 11,748 |
| Income tax receivable | 1,697 | 436 |
| Prepaid petroleum products | 0 | 8,071 |
| Other | 9,746 | 9,382 |
| Other current assets | $ 57,006 | $ 52,416 |