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Employee Benefits, Defined Benefit Plans Narrative (Details) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
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Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Accrued Annual Veba Contribution | $ 2.1 | $ 15.7 |
Defined Benefit Plan, Plan Assets, Amount | 68.1 | 72.3 |
Union VEBA |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Accrued Annual Veba Contribution |  | 12.8 |
Salaried VEBA |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Accrued Annual Veba Contribution | 2.1 | 2.9 |
Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year | 5.7 |  |
Defined Benefit Plan, Expected Amortization, Next Fiscal Year | 6.1 |  |
Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year | 0.4 |  |
VEBAs |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined Benefit Plan, Benefit Obligation | 85.6 | 90.0 | $ 86.8
Defined Benefit Plan, Plan Assets, Amount | 53.2 | 58.1 | 58.2
Salaried and certain hourly employee | Canadian pension plan | Maximum |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Estimated annual contribution to pension and other postretirement benefit plans | 2.9 |  |
Canadian pension plan | Canadian pension plan |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined Benefit Plan, Benefit Obligation | 7.3 | 8.5 | 7.0
Defined Benefit Plan, Plan Assets, Amount | 6.5 | 7.3 | $ 6.1
Defined Benefit Plan, Accumulated Benefit Obligation | 6.4 | $ 7.9 |
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year | $ 0.6 |  |
London Ontario Facility | Canadian pension plan | Canadian pension plan | Fixed Income Securities |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage | 34.00% |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 30.00% |  |
London Ontario Facility | Canadian pension plan | Canadian pension plan | Equity Securities |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage | 62.00% |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 65.00% |  |
London Ontario Facility | Canadian pension plan | Canadian pension plan | Short-term Investments |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 5.00% |  |

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