Pension and Other Postretirement Benefits - Narrative (Details) $ in Millions		6 Months Ended		12 Months Ended
	Jul. 01, 2018 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Pension and other postretirement benefits
Aggregate contributions to qualified and non-qualified pension trusts and payments of pension benefits for unfunded pension plans		$ 3.5	$ 6.3	$ 13.1
Expected 2020 aggregate contributions to qualified and non-qualified pension trusts and payments of pension benefits for unfunded pension and other postretirement plans		7.2
Accumulated funding deficiency demand		$ 1.3
Annual interest rate on accumulated funding deficiency demand		12.00%
Multiemployer Plan, Type [Extensible List]		us-gaap:PensionPlansDefinedBenefitMember
Pace Industry Union-Management Pension Fund
Pension and other postretirement benefits
Liability for plan withdrawal	$ 1.0
Multiemployer plan minimum contribution	$ 0.1
Minimum contribution period	20 years
Risk Free Interest Rate | Pace Industry Union-Management Pension Fund
Pension and other postretirement benefits
Multiemployer plans withdrawal liability measurement input	0.057