Retirement Plans - Amounts in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Pension Plan | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Net actuarial (loss) gain | $ (87.0) | $ 0.1 |
| Total | (87.0) | $ 0.1 |
| Other Postretirement Benefit Plan | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Net actuarial (loss) gain | 0.2 | |
| Total | $ 0.2 |