Goodwill and Identifiable Assets - Summary of Identifiable Intangible Assets with Definite and Indefinite Useful Lives (Details) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 129.3	$ 113.2
Accumulated Amortization	(93.4)	(82.0)
Net	35.9	31.2
Total identifiable intangible assets
Gross Carrying Value	138.2	122.1
Net	44.8	40.1
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	31.9	25.0
Accumulated Amortization	(19.0)	(17.5)
Net	12.9	7.5
Trademarks and tradenames with indefinite lives
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	0.7	0.6
Accumulated Amortization	(0.3)	(0.2)
Net	0.4	0.4
Capitalized software
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	48.7	42.6
Accumulated Amortization	(37.8)	(31.2)
Net	10.9	11.4
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	37.4	34.4
Accumulated Amortization	(26.7)	(24.2)
Net	10.7	10.2
Contracts
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	10.6	10.6
Accumulated Amortization	(9.6)	(8.9)
Net	$ 1.0	$ 1.7