Segment and Geographic Information - Narrative (Details) $ in Millions |
3 Months Ended | 9 Months Ended | |
|---|---|---|---|
|
Sep. 30, 2015
USD ($)
|
Sep. 30, 2016
Segment
Area
|
Sep. 30, 2015
USD ($)
|
|
| Segment Reporting [Abstract] | |||
| Number of operating segments | 2 | ||
| Number of reportable segments | 1 | ||
| Number of geographical areas | Area | 2 | ||
| Inventory holding gains | $ | $ 7.9 | $ 7.9 | |