Other Current Assets - Schedule of Other Current Assets (Detail) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] | ||
| Margin deposits with brokers | $ 33,193 | $ 37,089 |
| Natural gas transportation, current portion | 2,504 | 2,716 |
| Income tax receivable | 379 | 1,697 |
| Deposits | 0 | 5,758 |
| Other | 7,240 | 9,746 |
| Other current assets | $ 43,316 | $ 57,006 |