Retirement Plans and Post Retirement Benefits Asset Allocation and Fair Value of Plan Assets (Details) - USD ($) $ in Millions | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | $ 265.9 | | $ 239.9 | | $ 237.4 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 147.5 | | 151.2 | | |
Fair Value, Inputs, Level 2 | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 105.5 | | 76.5 | | |
Significant Unobservable Inputs (Level 3) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 12.9 | | 12.2 | | |
Multi-strategy Funds | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [1] | 82.5 | | 75.1 | | |
Multi-strategy Funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [1] | 69.6 | | 62.9 | | |
Multi-strategy Funds | Fair Value, Inputs, Level 2 | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [1] | 0 | | 0 | | |
Multi-strategy Funds | Significant Unobservable Inputs (Level 3) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 12.9 | [1] | 12.2 | [1] | $ 13.3 |
Cash and Cash Equivalents | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 3 | | 2.2 | | |
Cash and Cash Equivalents | Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | | 0 | | |
Cash and Cash Equivalents | Fair Value, Inputs, Level 2 | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 3 | | 2.2 | | |
Cash and Cash Equivalents | Significant Unobservable Inputs (Level 3) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | | 0 | | |
Domestic stock funds | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 56.2 | | 51.3 | | |
Domestic stock funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 42.2 | | 38 | | |
Domestic stock funds | Fair Value, Inputs, Level 2 | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 14 | | 13.3 | | |
Domestic stock funds | Significant Unobservable Inputs (Level 3) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 0 | | 0 | | |
International stock funds | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 43.1 | | 38.5 | | |
International stock funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 15.5 | | 13.5 | | |
International stock funds | Fair Value, Inputs, Level 2 | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 27.6 | | 25 | | |
International stock funds | Significant Unobservable Inputs (Level 3) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 0 | | 0 | | |
Domestic bond funds | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 40.2 | [3] | 36.8 | [2] | |
Domestic bond funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 20.2 | | 36.8 | | |
Domestic bond funds | Fair Value, Inputs, Level 2 | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 20 | | 0 | | |
Domestic bond funds | Significant Unobservable Inputs (Level 3) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 0 | | 0 | | |
International bond funds | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [3] | 40.9 | | 36 | | |
International bond funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 0 | | 0 | | |
International bond funds | Fair Value, Inputs, Level 2 | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | 40.9 | | 36 | | |
International bond funds | Significant Unobservable Inputs (Level 3) | | | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | [2] | $ 0 | | $ 0 | | |
UNITED STATES | | | | | | |
Target Allocations [Abstract] | | | | | | |
Target Plan Asset Allocation 2016 | | 100.00% | | | | |
Defined Benefit Plan, Actual Plan Asset Allocation | | 100.00% | | 100.00% | | |
UNITED STATES | Equity Securities | | | | | | |
Target Allocations [Abstract] | | | | | | |
Target Plan Asset Allocation 2016 | | 40.00% | | | | |
Defined Benefit Plan, Actual Plan Asset Allocation | | 40.00% | | 40.00% | | |
UNITED STATES | Debt Securities | | | | | | |
Target Allocations [Abstract] | | | | | | |
Target Plan Asset Allocation 2016 | | 20.00% | | | | |
Defined Benefit Plan, Actual Plan Asset Allocation | | 20.00% | | 20.00% | | |
UNITED STATES | Multi-strategy Funds | | | | | | |
Target Allocations [Abstract] | | | | | | |
Target Plan Asset Allocation 2016 | | 40.00% | | | | |
Defined Benefit Plan, Actual Plan Asset Allocation | | 40.00% | | 40.00% | | |
Non-US [Member] | | | | | | |
Target Allocations [Abstract] | | | | | | |
Target Plan Asset Allocation 2016 | | 100.00% | | | | |
Defined Benefit Plan, Actual Plan Asset Allocation | | 100.00% | | 100.00% | | |
Non-US [Member] | Equity Securities | | | | | | |
Target Allocations [Abstract] | | | | | | |
Target Plan Asset Allocation 2016 | | 27.10% | | | | |
Defined Benefit Plan, Actual Plan Asset Allocation | | 27.80% | | 29.00% | | |
Non-US [Member] | Debt Securities | | | | | | |
Target Allocations [Abstract] | | | | | | |
Target Plan Asset Allocation 2016 | | 71.30% | | | | |
Defined Benefit Plan, Actual Plan Asset Allocation | | 70.40% | | 70.00% | | |
Non-US [Member] | Cash and Cash Equivalents | | | | | | |
Target Allocations [Abstract] | | | | | | |
Target Plan Asset Allocation 2016 | | 1.60% | | | | |
Defined Benefit Plan, Actual Plan Asset Allocation | | 1.80% | | 1.00% | | |
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[1] | The multi-strategy funds invest in various hedge funds that employ a fund of funds strategy. | |
[2] | Equity investments include investments in funds that are primarily invested in large capitalization U.S. and international equity securities and a mutual fund. | |
[3] | Fixed income investments include investments in funds that are primarily invested in a diversified portfolio of investment grade U.S. and international debt securities. | |