Commitments and Contingencies - Operating Leases (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Operating Leased Assets [Line Items] | |||
| Fleet leases | $ 11,833 | $ 8,788 | $ 13,572 |
| Property, Plant and Equipment | |||
| Operating Leased Assets [Line Items] | |||
| 2016 | 4,734 | ||
| 2017 | 4,805 | ||
| 2018 | 4,071 | ||
| 2019 | 4,071 | ||
| 2020 | 4,072 | ||
| Thereafter | 7,880 | ||
| Total | 29,633 | ||
| Property, Plant and Equipment | Selling, General and Administrative Expenses | |||
| Operating Leased Assets [Line Items] | |||
| Rent expense | $ 400 | $ 300 | $ 300 |