Income Taxes - Components of Deferred Tax Asset and Liability (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Deferred tax asset:
Employment related accruals	$ 31.3	$ 27.8
Intangibles	15.4	13.5
Software development costs	51.6	14.9
Depreciation	18.1	11.2
Customer funds	17.0	31.2
Other	23.3	33.7
Foreign tax credit carryover and other credit carryovers	5.0	0.3
Net operating loss carryforwards	82.7	120.8
Total gross deferred tax asset	244.4	253.4
Valuation allowance	(55.0)	(44.1)
Total deferred tax asset	189.4	209.3
Deferred tax liability:
Intangibles	(49.5)	(60.8)
Deferred contract costs	(45.5)	(33.5)
Other	(12.9)	(19.0)
Total deferred tax liability	(107.9)	(113.3)
Net deferred tax asset	81.5	96.0
U.S. [Member]
Deferred tax liability:
Net deferred tax asset	66.8	79.8
International [Member]
Deferred tax asset:
Valuation allowance	(27.2)
Deferred tax liability:
Net deferred tax asset	$ 14.7	$ 16.2