Fair Value Measurements - Fair Value Liabilities Measured on Recurring Basis (Detail) - Fair Value Measurements at Reporting Date Using: Significant Unobservable Inputs (Level 3) [Member] - Fair Value, Measurements, Recurring [Member] $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance December 31, 2020	$ 48.2
Change in estimate	7.7
Settlements	(6.8)
Foreign currency impact	(0.5)
Ending balance September 30, 2021	$ 48.6