Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Assets
Total assets at fair value	$ 100.9	$ 194.8
Liabilities
Market-based share awards liability	0.5	0.5
Contingent consideration	75.1	10.7
Total liabilities at fair value	75.6	11.2
Cash and Cash Equivalents [Member]
Assets
Cash and cash equivalents	96.8	31.1
Money Market Mutual Funds [Member]
Assets
Cash and cash equivalents	4.1	163.7
Fair Value Measurements Recurring [Member] \| Level 1 [Member]
Assets
Total assets at fair value	100.9	194.8
Fair Value Measurements Recurring [Member] \| Level 3 [Member]
Liabilities
Market-based share awards liability	0.5	0.5
Contingent consideration	75.1	10.7
Total liabilities at fair value	75.6	11.2
Fair Value Measurements Recurring [Member] \| Cash and Cash Equivalents [Member] \| Level 1 [Member]
Assets
Cash and cash equivalents	96.8	31.1
Fair Value Measurements Recurring [Member] \| Money Market Mutual Funds [Member] \| Level 1 [Member]
Assets
Cash and cash equivalents	$ 4.1	$ 163.7

Fair value portion of asset recognized for present right to economic benefit.

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Amount of liability recognized arising from contingent consideration in a business combination.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements payable beyond one year (or the operating cycle, if longer).

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Fair value of financial and nonfinancial obligations.

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