Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 166.9	$ 69.4
Accumulated Amortization	(61.2)	(50.3)
Net Carrying Amount	105.7	19.1
Amortization of intangible assets	8.4	3.6	$ 4.2
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2018	14.7
2019	13.3
2020	11.5
2021	11.1
2022	9.7
Indefinite-lived trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7.9	7.5
Accumulated Amortization	0.0	0.0
Net Carrying Amount	7.9	7.5
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	137.5	50.2
Accumulated Amortization	(51.9)	(43.5)
Net Carrying Amount	$ 85.6	6.7
Weighted-average amortization period	8 years 10 months 24 days
Finite-lived trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 8.4	1.3
Accumulated Amortization	(2.3)	(1.2)
Net Carrying Amount	$ 6.1	0.1
Weighted-average amortization period	3 years 9 months 18 days
Amortization of intangible assets	$ 8.4
Other contract-related assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6.6	6.7
Accumulated Amortization	(3.0)	(2.4)
Net Carrying Amount	$ 3.6	4.3
Weighted-average amortization period	6 years 7 months 6 days
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 6.5	3.7
Accumulated Amortization	(4.0)	(3.2)
Net Carrying Amount	$ 2.5	0.5
Weighted-average amortization period	2 years 1 month 6 days
India | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Impairment charge		$ 6.5