Pensions and Other Postretirement Benefits - Additional Information (Details) - USD ($) $ in Millions		3 Months Ended			12 Months Ended
	Jan. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Lump sum settlements			$ 150.2
Non-cash settlement charge		$ 152.5	$ 39.2
Transfer of remaining pension benefit obligation to annuity	$ 713.0
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Company's contributions to its pension plans		0.6				$ 11.3
Pension Benefits | Minimum | Forecast
Defined Benefit Plan Disclosure [Line Items]
Company's contributions to its pension plans					$ 10.0
Pension Benefits | Maximum | Forecast
Defined Benefit Plan Disclosure [Line Items]
Company's contributions to its pension plans					20.0
Postretirement Health Care Benefits
Defined Benefit Plan Disclosure [Line Items]
Benefit payments		$ 0.7		$ 0.5		$ 1.2
Postretirement Health Care Benefits | Forecast
Defined Benefit Plan Disclosure [Line Items]
Benefit payments					$ 3.0