Pension and Other Post Retirement Benefits - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) Postretirement_Plan	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of Postretirement Plans | Postretirement_Plan		2
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 2.3	$ 2.3	$ 2.2
Defined Benefit Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement expense	$ 0.0	0.0	$ 2.1
Aggregate accumulated benefit obligation	481.6	450.5
Defined benefit plan, estimated future employer contributions in next fiscal year	5.7
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 3.6	$ 1.9