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Goodwill and Identifiable Assets Acquired Intangible Assets (Details) - USD ($) $ in Millions |  | 12 Months Ended
--- | --- | ---
Apr. 02, 2018 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Intangible Assets [Line Items] |  |  |  |
Amortization of intangible assets |  | $ 51.7 | $ 51.1 | $ 58.5
Identifiable intangible assets, net |  | 487.9 | 476.5 |
Intangible Assets, Gross (Excluding Goodwill) |  | 828.5 | 764.7 |
Intangible assets subject to amortization: |  |  |  |
Gross Carrying Amount |  | 569.6 | 505.8 |
Accumulated Amortization |  | 340.6 | 288.2 |
Net Carrying Amount |  | 229.0 | 217.6 |
Intangible assets not subject to amortization: |  |  |  |
Trademarks, Carrying Amount |  | 258.9 | 258.9 |
Minimum [Member] |  |  |  |
Intangible assets not subject to amortization: |  |  |  |
Finite-Lived Intangible Asset, Useful Life | 4 years |  |  |
Maximum [Member] |  |  |  |
Intangible assets not subject to amortization: |  |  |  |
Finite-Lived Intangible Asset, Useful Life | 7 years |  |  |
Other Acquisitions |  |  |  |
Intangible assets subject to amortization: |  |  |  |
Gross Carrying Amount |  | $ 62.9 |  |
Intangible assets not subject to amortization: |  |  |  |
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life |  | 7 years 6 months |  |
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life |  | 7 years 6 months |  |
2019 Acquisitions |  |  |  |
Intangible assets subject to amortization: |  |  |  |
Gross Carrying Amount |  |  | $ 42.8 |
Intangible assets not subject to amortization: |  |  |  |
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life |  |  | 10 years 6 months |
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life |  |  | 10 years 6 months |
Contractual customer relationships |  |  |  |
Intangible assets subject to amortization: |  |  |  |
Gross Carrying Amount |  | $ 441.3 | $ 384.9 |
Accumulated Amortization |  | 222.9 | 179.9 |
Net Carrying Amount |  | $ 218.4 | 205.0 |
Contractual customer relationships | Minimum [Member] |  |  |  |
Intangible assets not subject to amortization: |  |  |  |
Finite-Lived Intangible Asset, Useful Life |  | 7 years 3 months 18 days |  |
Contractual customer relationships | Maximum [Member] |  |  |  |
Intangible assets not subject to amortization: |  |  |  |
Finite-Lived Intangible Asset, Useful Life |  | 12 years 9 months |  |
Contractor relations |  |  |  |
Intangible assets subject to amortization: |  |  |  |
Gross Carrying Amount |  | $ 71.2 | 71.1 |
Accumulated Amortization |  | 71.0 | 70.6 |
Net Carrying Amount |  | 0.2 | 0.5 |
Backlog |  |  |  |
Intangible assets subject to amortization: |  |  |  |
Gross Carrying Amount |  | 29.3 | 25.0 |
Accumulated Amortization |  | 28.5 | 23.9 |
Net Carrying Amount |  | $ 0.8 | 1.1 |
Backlog | Minimum [Member] |  |  |  |
Intangible assets not subject to amortization: |  |  |  |
Finite-Lived Intangible Asset, Useful Life |  | 1 year |  |
Backlog | Maximum [Member] |  |  |  |
Intangible assets not subject to amortization: |  |  |  |
Finite-Lived Intangible Asset, Useful Life |  | 2 years 9 months |  |
Non-compete agreements |  |  |  |
Intangible assets subject to amortization: |  |  |  |
Gross Carrying Amount |  | $ 27.8 | 24.8 |
Accumulated Amortization |  | 18.2 | 13.8 |
Net Carrying Amount |  | $ 9.6 | $ 11.0 |
Non-compete agreements | Minimum [Member] |  |  |  |
Intangible assets not subject to amortization: |  |  |  |
Finite-Lived Intangible Asset, Useful Life |  | 4 years |  |
Non-compete agreements | Maximum [Member] |  |  |  |
Intangible assets not subject to amortization: |  |  |  |
Finite-Lived Intangible Asset, Useful Life |  | 7 years |  |

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