Retirement Plans - Amounts Recognized in Other Comprehensive Income (Loss) (Details) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2016
USD ($)
| |
| Pension Plan | |
| Amortization of: | |
| Net actuarial loss | $ 0.7 |
| Amounts arising during the period: | |
| Net actuarial gain | 10.9 |
| Total | 11.6 |
| Other Postretirement Benefit Plan | |
| Amortization of: | |
| Net actuarial loss | 0.0 |
| Amounts arising during the period: | |
| Net actuarial gain | 0.3 |
| Total | $ 0.3 |