Segment information - Capital Expenditures, Depreciation, Amortization (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Capital Expenditures by Reportable Segment	$ 51.1	$ 30.7	$ 36.6	$ 36.7	$ 57.1	$ 46.3	$ 43.3	$ 27.8	$ 155.1	$ 174.5	$ 112.2
Depreciation and Amortization by Reportable Segment									144.6	138.2	128.0
Amortization of intangible assets:									17.7	8.4	3.6
Total	$ 42.8	$ 41.6	$ 39.1	$ 38.8	$ 40.2	$ 37.9	$ 34.6	$ 33.9	162.3	146.6	131.6
Reportable Segments:
Segment Reporting Information [Line Items]
Capital Expenditures by Reportable Segment									140.3	161.4	98.2
Depreciation and Amortization by Reportable Segment									129.7	122.3	115.6
Reportable Segments: | North America
Segment Reporting Information [Line Items]
Capital Expenditures by Reportable Segment									59.1	86.3	42.0
Depreciation and Amortization by Reportable Segment									72.1	68.4	66.8
Reportable Segments: | South America
Segment Reporting Information [Line Items]
Capital Expenditures by Reportable Segment									43.3	39.2	24.0
Depreciation and Amortization by Reportable Segment									26.3	23.5	19.0
Reportable Segments: | Rest of World
Segment Reporting Information [Line Items]
Capital Expenditures by Reportable Segment									37.9	35.9	32.2
Depreciation and Amortization by Reportable Segment									31.3	30.4	29.8
Corporate items
Segment Reporting Information [Line Items]
Capital Expenditures by Reportable Segment									14.8	8.9	9.0
Depreciation and Amortization by Reportable Segment									11.9	12.0	10.9
Venezuela | Other items not allocated to segments:
Segment Reporting Information [Line Items]
Capital Expenditures by Reportable Segment									0.0	4.2	5.0
Depreciation and Amortization by Reportable Segment									1.1	1.7	0.7
Reorganization and Restructuring | Other items not allocated to segments:
Segment Reporting Information [Line Items]
Depreciation and Amortization by Reportable Segment									$ 1.9	$ 2.2	$ 0.8