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Goodwill and Identifiable Assets (Acquired Intangible Assets) (Details) - USD ($) $ in Millions | 6 Months Ended |
--- | --- | ---
Jun. 30, 2020 | Dec. 31, 2019
Intangible assets subject to amortization: |  |
Gross Carrying Amount | $ 547.5 | $ 524.7
Accumulated Amortization | 331.8 | 307.1
Net Carrying Amount | 215.7 | 217.6
Intangible assets not subject to amortization: |  |
Trademarks, Carrying Amount | 258.9 | 258.9
Intangible Assets, Gross (Excluding Goodwill) | 806.4 | 783.6
Intangible Assets, Net (Excluding Goodwill) | 474.6 | 476.5
Customer and Contractual Relationships |  |
Intangible assets subject to amortization: |  |
Gross Carrying Amount | 403.6 | 384.9
Accumulated Amortization | 200.4 | 179.9
Net Carrying Amount | $ 203.2 | 205.0
Customer and Contractual Relationships | Minimum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 2 months |
Customer and Contractual Relationships | Maximum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 12 years 9 months |
Contractor Relations |  |
Intangible assets subject to amortization: |  |
Gross Carrying Amount | $ 71.1 | 71.1
Accumulated Amortization | 70.7 | 70.6
Net Carrying Amount | $ 0.4 | 0.5
Contractor Relations | Minimum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 2 years |
Contractor Relations | Maximum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 5 years |
Backlog |  |
Intangible assets subject to amortization: |  |
Gross Carrying Amount | $ 28.3 | 25.0
Accumulated Amortization | 25.9 | 23.9
Net Carrying Amount | $ 2.4 | 1.1
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 |
Noncompete Agreements |  |
Intangible assets subject to amortization: |  |
Gross Carrying Amount | $ 25.6 | 24.8
Accumulated Amortization | 15.9 | 13.8
Net Carrying Amount | $ 9.7 | 11.0
Noncompete Agreements | Minimum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 2 years |
Noncompete Agreements | Maximum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 7 years |
In-use software |  |
Intangible assets subject to amortization: |  |
Gross Carrying Amount | $ 18.9 | 18.9
Accumulated Amortization | 18.9 | 18.9
Net Carrying Amount | $ 0.0 | $ 0.0
In-use software | Minimum [Member] |  |
Intangible Assets [Line Items] |  |
Finite-Lived Intangible Asset, Useful Life | 6 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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