Discontinued Operations (Details) - Discontinued Operations, Disposed of by Sale [Member] - Media - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Discontinued operations | ||
| Assets of discontinued operations | $ 0.0 | $ 0.0 |
| Liabilities of discontinued operations | 0.0 | 0.0 |
| Accrued Liabilities [Member] | ||
| Discontinued operations | ||
| Lease impairment liability | $ 0.1 | $ 0.2 |