Goodwill and Identifiable Intangible Assets, net - Summary of Identifiable Intangible Assets, net (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 196.0	$ 172.0
Accumulated Amortization	(102.6)	(97.3)
Net	93.4	74.7
Total identifiable intangible assets, net
Gross Carrying Value	204.9	180.9
Net	102.3	83.6
Trademarks and tradenames with indefinite lives
Indefinite-lived Intangible Assets [Line Items]
Trademarks and tradenames with indefinite lives	8.9	8.9
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	71.1	59.7
Accumulated Amortization	(21.5)	(19.7)
Net	49.6	40.0
Trademarks and tradenames with indefinite lives
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	13.3	11.6
Accumulated Amortization	(1.1)	(0.5)
Net	12.2	11.1
Capitalized software
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	60.6	50.6
Accumulated Amortization	(46.9)	(40.0)
Net	13.7	10.6
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	37.4	39.2
Accumulated Amortization	(23.1)	(27.5)
Net	14.3	11.7
Contracts
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	13.6	10.9
Accumulated Amortization	(10.0)	(9.6)
Net	$ 3.6	$ 1.3