Employee Benefit Plans - Fair Value Measurement of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 190.2	$ 174.9	$ 183.4
Cash/Money Markets
Defined Benefit Plan Disclosure [Line Items]
Plan assets	4.5	4.6
Foreign Government/Treasury Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets	19.4	17.3
Corporate Bonds, Debentures
Defined Benefit Plan Disclosure [Line Items]
Plan assets	35.3	33.3
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets	40.4	32.3
Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	8.0	7.3
Investment and Insurance Annuity Contracts
Defined Benefit Plan Disclosure [Line Items]
Plan assets	82.6	80.1
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Plan assets	23.9	21.9
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Cash/Money Markets
Defined Benefit Plan Disclosure [Line Items]
Plan assets	4.5	4.6
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Foreign Government/Treasury Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets	19.4	17.3
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Corporate Bonds, Debentures
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Investment and Insurance Annuity Contracts
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Plan assets	114.3	102.4
Significant Observable Inputs (Level 2) \| Cash/Money Markets
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Significant Observable Inputs (Level 2) \| Foreign Government/Treasury Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Significant Observable Inputs (Level 2) \| Corporate Bonds, Debentures
Defined Benefit Plan Disclosure [Line Items]
Plan assets	35.3	33.3
Significant Observable Inputs (Level 2) \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets	40.4	32.3
Significant Observable Inputs (Level 2) \| Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	8.0	7.3
Significant Observable Inputs (Level 2) \| Investment and Insurance Annuity Contracts
Defined Benefit Plan Disclosure [Line Items]
Plan assets	30.6	29.5
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Plan assets	52.0	50.6
Significant Unobservable Inputs (Level 3) \| Cash/Money Markets
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) \| Foreign Government/Treasury Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) \| Corporate Bonds, Debentures
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) \| Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Significant Unobservable Inputs (Level 3) \| Investment and Insurance Annuity Contracts
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 52.0	$ 50.6	$ 55.2