Fair Value Measurements - Asset and Liability Measured at Fair Value Measured on Recurring Basis (Detail) - USD ($) $ in Millions		Jun. 30, 2022	Dec. 31, 2021
Assets
Available for sale customer funds assets		$ 2,042.3	$ 1,952.4
Total assets measured at fair value		2,042.3	1,952.4
Liabilities
DataFuzion contingent consideration		8.0	6.0
Total liabilities measured at fair value		8.0	6.0
Fair Value, Inputs, Level 2 [Member]
Assets
Available for sale customer funds assets	[1]	2,042.3	1,952.4
Total assets measured at fair value		2,042.3	1,952.4
Fair Value, Inputs, Level 3 [Member]
Liabilities
DataFuzion contingent consideration	[2]	8.0	6.0
Total liabilities measured at fair value		$ 8.0	$ 6.0

[1] Fair value is based on inputs that are observable for the asset or liability, other than quoted prices.

[2] For the contingent consideration related to the 2021 acquisition of certain assets and liabilities of DataFuzion HCM, Inc. ("DataFuzion"), we utilize an option pricing model, specifically a Black-Scholes-Merton model, to estimate the fair value of the contingent liability as of the reporting dates. This model uses certain assumptions related to risk-free rates and volatility as well as certain judgments in forecasting annual recurring revenue. The contingent consideration has been measured as Level 3 given the unobservable inputs that are significant to the measurement of liability. The contingent consideration is included within other liabilities in our condensed consolidated balance sheets.