Summary of Significant Accounting Policies - Summary of Intangible Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 373.5	$ 448.0
Accumulated Amortization	(86.4)	(191.8)
Net Carrying Value	$ 287.1	$ 256.2
Weighted Average Useful Life (years)	7 years 6 months	8 years 8 months 12 days
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 24.6	$ 31.1
Accumulated Amortization	(16.4)	(19.4)
Net Carrying Value	$ 8.2	$ 11.7
Weighted Average Useful Life (years)	8 years 7 months 6 days	7 years 8 months 12 days
Customer-based
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 338.2	$ 406.0
Accumulated Amortization	(68.3)	(172.4)
Net Carrying Value	$ 269.9	$ 233.6
Weighted Average Useful Life (years)	7 years 4 months 24 days	8 years 9 months 18 days
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 10.7	$ 10.9
Accumulated Amortization	(1.7)	0.0
Net Carrying Value	$ 9.0	$ 10.9
Weighted Average Useful Life (years)	5 years 9 months 18 days	5 years 8 months 12 days