Summary of Significant Accounting Policies - Aircraft, Net and Property, Plant, and Equipment, Net (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Property, Plant and Equipment [Line Items] | |||
| Cost of repair and maintenance | $ 20.1 | $ 22.9 | $ 20.0 |
| Aircraft | |||
| Property, Plant and Equipment [Line Items] | |||
| Useful life (in years) | 15 years | ||
| Buildings | |||
| Property, Plant and Equipment [Line Items] | |||
| Useful life (in years) | 20 years | ||
| Vehicles and equipment | Minimum | |||
| Property, Plant and Equipment [Line Items] | |||
| Useful life (in years) | 3 years | ||
| Vehicles and equipment | Maximum | |||
| Property, Plant and Equipment [Line Items] | |||
| Useful life (in years) | 5 years | ||