Intangible Assets and Goodwill - Summary of Intangible Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Schedule Of Intangible Assets Excluding Goodwill [Line Items]
Gross carrying amount	$ 615.6	$ 560.0
Accumulated amortization	(434.2)	(404.1)
Net carrying amount	181.4	155.9
Trade Names [Member]
Schedule Of Intangible Assets Excluding Goodwill [Line Items]
Gross carrying amount	45.7	45.7
Net carrying amount	45.7	45.7
Customer Relationship Intangibles [Member]
Schedule Of Intangible Assets Excluding Goodwill [Line Items]
Gross carrying amount	391.9	363.6
Accumulated amortization	(356.7)	(343.5)
Net carrying amount	35.2	20.1
Trade Names [Member]
Schedule Of Intangible Assets Excluding Goodwill [Line Items]
Gross carrying amount	112.2	92.3
Accumulated amortization	(34.4)	(27.6)
Net carrying amount	77.8	64.7
Acquired Technology [Member]
Schedule Of Intangible Assets Excluding Goodwill [Line Items]
Gross carrying amount	8.4	8.4
Accumulated amortization	(6.6)	(5.7)
Net carrying amount	1.8	2.7
Acquired Content [Member]
Schedule Of Intangible Assets Excluding Goodwill [Line Items]
Gross carrying amount	2.6	2.6
Accumulated amortization	(1.8)	(1.4)
Net carrying amount	0.8	1.2
Computer Software [Member]
Schedule Of Intangible Assets Excluding Goodwill [Line Items]
Gross carrying amount	52.9	45.1
Accumulated amortization	(34.7)	(25.9)
Net carrying amount	18.2	19.2
Capitalized Software in Progress [Member]
Schedule Of Intangible Assets Excluding Goodwill [Line Items]
Gross carrying amount	1.9	2.3
Net carrying amount	$ 1.9	$ 2.3