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Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
SEC Schedule, 12-09, Allowance, Credit Loss [Member] |  |  |  |
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] |  |  |  |
Balance at Beginning of Year |  | $ 23.0 | $ 11.1 | $ 8.3
Amounts Recorded in Earnings |  | 12.2 | 26.0 | 6.8
Adjustments | [1] | (13.4) | (14.1) | (4.0)
Balance at End of Year |  | 21.8 | 23.0 | 11.1
Allowance for Estimated Policy Cancellations [Member] |  |  |  |
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] |  |  |  |
Balance at Beginning of Year |  | 9.9 | 9.3 | 10.0
Amounts Recorded in Earnings |  | 3.0 | (0.5) | 2.4
Adjustments | [2] | 0.4 | 1.1 | (3.1)
Balance at End of Year |  | 13.3 | 9.9 | 9.3
Valuation Allowance for Deferred Tax Assets [Member] |  |  |  |
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] |  |  |  |
Balance at Beginning of Year |  | 195.8 | 135.2 | 154.9
Amounts Recorded in Earnings |  | (19.3) | 60.6 | (19.7)
Balance at End of Year |  | 176.5 | 195.8 | 135.2
Accumulated Amortization of Expiration Lists, Non-compete Agreements and Trade Names [Member] |  |  |  |
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] |  |  |  |
Balance at Beginning of Year |  | 3,873.5 | 3,300.0 | 2,924.0
Amounts Recorded in Earnings |  | 664.8 | 531.3 | 454.9
Adjustments | [3] | (67.0) | 42.2 | (78.9)
Balance at End of Year |  | $ 4,471.3 | $ 3,873.5 | $ 3,300.0
[1] | Net activity of bad debt write offs and recoveries and acquired businesses.
[2] | Net activity to allowance related to acquired businesses.
[3] | Elimination of fully amortized expiration lists, non-compete agreements and trade names, intangible asset/amortization reclassifications and disposal of acquired businesses.

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