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Intangible Assets - Major Classes of Amortizable Intangible Assets (Detail) - USD ($) $ in Millions | Dec. 31, 2020 | Dec. 31, 2019
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Finite-Lived Intangible Assets [Line Items] |  |
Amortizable intangible assets, net | $ 2,399.9 | $ 2,318.7
Expiration Lists [Member] |  |
Finite-Lived Intangible Assets [Line Items] |  |
Amortizable intangible assets, gross | 4,753.2 | 4,246.0
Accumulated amortization | (2,436.7) | (2,004.3)
Amortizable intangible assets, net | 2,316.5 | 2,241.7
Non-Compete Agreements [Member] |  |
Finite-Lived Intangible Assets [Line Items] |  |
Amortizable intangible assets, gross | 75.9 | 68.4
Accumulated amortization | (57.8) | (52.5)
Amortizable intangible assets, net | 18.1 | 15.9
Trade Names [Member] |  |
Finite-Lived Intangible Assets [Line Items] |  |
Amortizable intangible assets, gross | 107.8 | 91.8
Accumulated amortization | (42.5) | (30.7)
Amortizable intangible assets, net | $ 65.3 | $ 61.1

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