Fair Value Measurement - Fair Value, Valuation Techniques and Related Unobservable Inputs for Level Three (Detail) - Customer Relationships - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	$ 98.4	$ 178.2
Fair Value, Inputs, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	$ 0.0	$ 0.0	$ 0.0
Discount rate			16.00%
Attrition rate	2.70%
Fair Value, Inputs, Level 3 | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rate		12.00%
Attrition rate		6.60%
Fair Value, Inputs, Level 3 | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rate		18.00%
Attrition rate		12.00%