Segment Information - Revenues, operating profit, total assets, and long-lived assets for Mexico operations (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting [Abstract]
Number of Reportable Segments | segment									3
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 735.0	$ 606.9	$ 634.0	$ 533.2	$ 615.4	$ 655.7	$ 595.7	$ 530.6	$ 2,509.1	$ 2,397.4	$ 3,089.8
Total Assets	7,989.2				9,543.2				7,989.2	9,543.2
Operating profit	89.8	$ 75.2	$ 88.0	$ 62.1	115.5	$ 105.1	$ 83.1	$ 64.6	315.1	368.3	$ 478.9
Mexico:
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Assets	116.0				119.6				116.0	119.6
Long-Lived Assets	$ 84.2				$ 99.6				$ 84.2	$ 99.6