Leasing - Lease cost in income statement (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Lessee, Lease, Description [Line Items]
Operating Leases	$ 14.0	$ 12.4	$ 27.7	$ 25.3
Finance Leases	6.9	5.5	13.8	10.7
Total	20.9	17.9	41.5	36.0
Depreciation	5.9	4.8	12.1	9.4
Interest expense	1.0	0.7	1.7	1.3
Variable lease costs	0.2	0.7	0.4	0.9
Short-term lease costs	6.4	9.0	13.9	11.6
Total gross lease costs	27.5	27.6	55.8	48.5
Sublease income	0.6	0.6	1.2	1.6
Total net lease cost	26.9	27.0	54.6	46.9
Cost of goods sold (exclusive of depreciation)
Lessee, Lease, Description [Line Items]
Operating Leases	4.4	4.0	8.7	7.7
Finance Leases	0.0	0.0	0.0	0.0
Total	4.4	4.0	8.7	7.7
Outbound freight and handling
Lessee, Lease, Description [Line Items]
Operating Leases	1.4	1.9	2.7	3.7
Finance Leases	0.0	0.0	0.0	0.0
Total	1.4	1.9	2.7	3.7
Warehousing, selling and administrative
Lessee, Lease, Description [Line Items]
Operating Leases	8.2	6.5	16.3	13.9
Finance Leases	0.0	0.0	0.0	0.0
Total	$ 8.2	$ 6.5	$ 16.3	$ 13.9