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Goodwill and Identifiable Assets (Acquired Intangible Assets) (Details) - USD ($) $ in Millions | 6 Months Ended |
--- | --- | ---
Jun. 30, 2021 | Dec. 31, 2020
Intangible assets subject to amortization: |  |
Gross Carrying Amount | $ 559.4 | $ 529.8
Accumulated Amortization | 326.5 | 302.5
Net Carrying Amount | 232.9 | 227.3
Intangible assets not subject to amortization: |  |
Trademarks, Carrying Amount | 242.6 | 242.6
Intangible Assets, Gross (Excluding Goodwill) | 802.0 | 772.4
Intangible Assets, Net (Excluding Goodwill), Total | 475.5 | 469.9
Customer and Contractual Relationships |  |
Intangible assets subject to amortization: |  |
Accumulated Amortization | 232.6 | 211.3
Net Carrying Amount | 224.8 | 216.7
Total |  |
Other Finite-Lived Intangible Assets, Gross | $ 457.4 | 428.0
Customer and Contractual Relationships | Minimum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 7 years 3 months 18 days |
Customer and Contractual Relationships | Maximum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 12 years 9 months 18 days |
Contractor Relations |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 4 years |
Intangible assets subject to amortization: |  |
Accumulated Amortization | $ 45.4 | 45.3
Net Carrying Amount | 0.1 | 0.2
Total |  |
Other Finite-Lived Intangible Assets, Gross | 45.5 | 45.5
Backlog |  |
Intangible assets subject to amortization: |  |
Accumulated Amortization | 28.9 | 28.5
Net Carrying Amount | 0.4 | 0.8
Total |  |
Other Finite-Lived Intangible Assets, Gross | $ 29.3 | 29.3
Backlog | Minimum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 1 year |
Backlog | Maximum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 2 years 9 months 18 days |
Noncompete Agreements |  |
Intangible assets subject to amortization: |  |
Accumulated Amortization | $ 19.6 | 17.4
Net Carrying Amount | 7.6 | 9.6
Total |  |
Other Finite-Lived Intangible Assets, Gross | $ 27.2 | $ 27.0
Noncompete Agreements | Minimum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 1 year |
Noncompete Agreements | Maximum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 7 years |

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- Definition Carrying amount (original costs adjusted for previously recognized amortization and impairment) as of the balance sheet date for the rights acquired through registration of a trademark to gain or protect exclusive use of a business name, symbol or other device or style for a projected indefinite period of benefit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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