Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 2,227.5
Other comprehensive income (loss) before income taxes and reclassifications	(53.6)
Income tax benefit (expense)	17.6
Reclassifications to earnings	2.9
Other comprehensive income (loss)	(33.1)
Ending balance	2,140.8
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(177.3)
Other comprehensive income (loss) before income taxes and reclassifications	15.6
Other comprehensive income (loss)	15.6
Ending balance	(161.7)
Unrealized Gain (Loss) from Invested Customer Funds [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	2.8
Other comprehensive income (loss) before income taxes and reclassifications	(69.4)
Income tax benefit (expense)	18.4
Other comprehensive income (loss)	(51.0)
Ending balance	(48.2)
Pension Liability Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(150.3)
Other comprehensive income (loss) before income taxes and reclassifications	0.2
Income tax benefit (expense)	(0.8)
Reclassifications to earnings	2.9
Other comprehensive income (loss)	2.3
Ending balance	(148.0)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(324.8)
Ending balance	$ (357.9)