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Fair Value Measurements (Fair Value of Assets and Liabilities) (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Assets: |  |
Deferred compensation assets | $ 8.9 | $ 7.4
Foreign currency contracts | 0.5 | 0.2
Total assets at fair value | 9.4 | 7.6
Liabilities: |  |
Contingent consideration | 4.9 | 8.0
Deferred compensation liabilities | 9.9 | 8.4
Interest rate swap contracts |  | 1.0
Foreign currency contracts | 5.1 | 1.6
Total liabilities at fair value | 19.9 | 19.0
Other Financial Instruments [Abstract] |  |
Long-term debt, fair value | 201.5 | 228.3
Long-term debt | 197.0 | 226.2
Level 1 [Member] |  |
Assets: |  |
Deferred compensation assets | 8.9 | 7.4
Total assets at fair value | 8.9 | 7.4
Liabilities: |  |
Deferred compensation liabilities | 9.9 | 8.4
Total liabilities at fair value | 9.9 | 8.4
Level 2 [Member] |  |
Assets: |  |
Foreign currency contracts | 0.5 | 0.2
Total assets at fair value | 0.5 | 0.2
Liabilities: |  |
Interest rate swap contracts |  | 1.0
Foreign currency contracts | 5.1 | 1.6
Total liabilities at fair value | 5.1 | 2.6
Level 3 [Member] |  |
Liabilities: |  |
Contingent consideration | 4.9 | 8.0
Total liabilities at fair value | $ 4.9 | $ 8.0

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