Commitments and Contingencies - Contracts Containing Liquidated Damages Provisions (Narrative) (Details) - USD ($) $ in Millions |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Loss Contingencies [Line Items] | ||
| Estimated penalties for liquidated damages | $ 3.1 | $ 3.1 |
| Contracts containing liquidated damages | ||
| Loss Contingencies [Line Items] | ||
| Estimated penalties for liquidated damages | $ 22.3 |