Leases - Balance sheet by asset category (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lessee, Lease, Description [Line Items]
Operating lease ROU Asset	$ 50.2	$ 43.3
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Property, plant and equipment, gross	$ 677.2	$ 595.6
Less: Accumulated depreciation	(429.0)	(398.8)
Property, plant and equipment, net	248.2	196.8	$ 200.7
Finance Leased Asset
Lessee, Lease, Description [Line Items]
Less: Accumulated depreciation	(7.1)	(6.1)
Property, plant and equipment, net	2.4	4.6
Finance Leased Real Estate
Lessee, Lease, Description [Line Items]
Property, plant and equipment, gross	9.4	10.6
Finance Leased Machinery and Equipment
Lessee, Lease, Description [Line Items]
Property, plant and equipment, gross	0.1	0.1
Real Estate
Lessee, Lease, Description [Line Items]
Operating lease ROU Asset	45.9	40.0
Automobile
Lessee, Lease, Description [Line Items]
Operating lease ROU Asset	3.6	2.4
Machinery and equipment.
Lessee, Lease, Description [Line Items]
Operating lease ROU Asset	$ 0.7	$ 0.9