Inventories - Schedule of Inventories (Detail) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Inventory [Line Items] | ||
| Inventories | $ 318,899 | $ 241,320 |
| Petroleum and related products | ||
| Inventory [Line Items] | ||
| Inventories | 305,827 | 215,048 |
| Asphalt | ||
| Inventory [Line Items] | ||
| Inventories | 7,089 | 20,677 |
| Coal | ||
| Inventory [Line Items] | ||
| Inventories | 3,149 | 3,713 |
| Natural gas | ||
| Inventory [Line Items] | ||
| Inventories | $ 2,834 | $ 1,882 |