Fair Value Measurements of Assets and Liabilities - Fair Value Measurements of Assets and Liabilities (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	$ 1.4	$ 99.6
Contingent payments related to acquisitions	48.2	28.8
Total Liabilities	183.2	29.4
Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	1.4	99.6
Total Liabilities	135.0	0.6
Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent payments related to acquisitions	48.2	28.8
Total Liabilities	48.2	28.8
Foreign Exchange Forward Contracts [Member] | Derivatives Designated as Hedges [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term	0.5	39.1
Derivatives, current and long-term	48.5	0.6
Foreign Exchange Forward Contracts [Member] | Derivatives Not Designated as Hedges [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term	0.9
Derivatives, current and long-term	3.2
Foreign Exchange Forward Contracts [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member] | Derivatives Designated as Hedges [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term	0.5	39.1
Derivatives, current and long-term	48.5	0.6
Foreign Exchange Forward Contracts [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member] | Derivatives Not Designated as Hedges [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term	0.9
Derivatives, current and long-term	3.2
Interest Rate Swaps [Member] | Derivatives Designated as Hedges [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term		60.5
Derivatives, current and long-term	83.3
Interest Rate Swaps [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member] | Derivatives Designated as Hedges [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, current and long-term		$ 60.5
Derivatives, current and long-term	$ 83.3