Debt - Minimum Repayments Long Term Debt (Details) $ in Millions	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
2018	$ 51.9
2019	46.1
2020	43.2
2021	40.2
2022	406.7
Later years	614.5
Total	1,202.6
Capital leases
Debt Instrument [Line Items]
2018	22.6
2019	18.4
2020	16.7
2021	15.0
2022	12.8
Later years	11.4
Total	96.9
Other long-term debt
Debt Instrument [Line Items]
2018	29.3
2019	27.7
2020	26.5
2021	25.2
2022	393.9
Later years	603.1
Total	$ 1,105.7