Financial Instruments and Contingent Consideration (Estimated Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Acquisition-related contingent consideration	$ (5.3)	$ 0.0
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, including current portion	(627.4)	(715.5)
Acquisition-related contingent consideration	(7.1)	(16.9)
Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, including current portion	(623.6)	(715.5)
Acquisition-related contingent consideration	(7.1)	(16.9)
Interest Rate Swap Contracts [Member] \| Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap contracts	(20.3)	(28.9)
Interest Rate Swap Contracts [Member] \| Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap contracts	$ (20.3)	$ (28.9)

Amount of liability recognized arising from contingent consideration in a business combination.

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- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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