Inventories - Components of Inventories (Details) - USD ($) $ in Millions |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Inventory Net [Abstract] | ||
| Raw materials and manufacturing supplies | $ 7.6 | $ 8.0 |
| Work in process | 10.8 | 9.6 |
| Finished goods | 5.7 | 4.6 |
| Total | $ 24.1 | $ 22.2 |