Other Consolidated Balance Sheet Accounts Detail (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of year	$ 8.3	$ 7.3	$ 7.1
Net additions charged to operations	7.1	3.6	1.1
Less: Write-offs and adjustments	(0.9)	(2.6)	(0.9)
Balance, end of year	14.5	8.3	$ 7.3
Other Receivables, Net, Current [Abstract]
Vendor receivables, net	73.1	72.7
Insurance recoverables, current	3.1	2.2
Other miscellaneous receivables	20.0	14.5
Total other receivables, net	96.2	89.4
Deposits and Prepayments [Abstract]
Vendor prepayments	85.8	45.4
Prepaid taxes	0.5	3.6
Deposits	7.0	7.8
Racking allowances, current	6.8	6.4
Other prepayments	15.9	15.6
Total deposits and prepayments	116.0	78.8
Other Assets, Noncurrent [Abstract]
Insurance recoverables	14.4	11.3
Racking allowances, net	3.5	6.7
Insurance deposits	3.4	3.5
Debt issuance costs	1.0	1.8
Other assets	6.3	1.9
Total other non-current assets, net	28.6	25.2
Accrued Liabilities, Current [Abstract]
Accrued payroll and other benefits	47.7	40.9
Accrued customer incentives payable	37.3	34.0
Claims liabilities, current	20.4	16.4
Indirect taxes	9.3	7.2
Vendor advances	3.1	3.0
Other accrued expenses	33.2	32.5
Total accrued liabilities	$ 151.0	$ 134.0