For contingent consideration arrangements recognized in connection with a business combination, if the maximum (undiscounted) potential outcome is limitless, this element represents a statement of that fact.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
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- Definition

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

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- Definition

For contingent consideration arrangements and indemnification assets recognized in connection with a business combination, this element represents an estimate of the low-end of the potential range (undiscounted) of the consideration which may be paid.

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- Definition

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.

+ References

No definition available.

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Fair value of obligations measured on a recurring basis.

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-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
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Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of purchases of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of settlements of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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- Definition

Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Fair Value of Financial Instruments (Acquisition-Related Contingent Consideration) (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Fair Value, Financial Instruments Measured on a Recurring Basis [Line Items]
Acquisition-related contingent consideration liabilities, range of potential undiscounted earn-out liabilities, low	$ 23,000,000		$ 23,000,000
Acquisition-related contingent consideration liabilities, range of potential undiscounted earn-out liabilities, high	173,000,000		$ 173,000,000
Acquisition-related contingent consideration liabilities, range of potential earn-out liabilities, maximum unlimited			there is no maximum payment amount
Acquisition-related contingent consideration liabilities, net increase (decrease), measurement period adjustments			$ 3,800,000
Earn-Out Liabilities [Member]
Fair Value, Financial Instruments Measured on a Recurring Basis [Line Items]
Acquisition-related contingent consideration liabilities, estimated fair value	110,100,000		110,100,000		$ 117,200,000
Acquisition-related contingent consideration liabilities, additions from new business combinations	0	$ 64,600,000	1,500,000	$ 89,600,000
Acquisition-related contingent consideration liabilities, net increase (decrease), measurement period adjustments	2,200,000		4,200,000
Acquisition-related contingent consideration liabilities, net increase (decrease), loss (gain) recorded in earnings	5,900,000	(3,000,000)	10,300,000	(11,600,000)
Acquisition-related contingent consideration liabilities, payments	0	$ 0	23,100,000	$ 18,800,000
Earn-Out Liabilities [Member] \| Other Current Liabilities [Member]
Fair Value, Financial Instruments Measured on a Recurring Basis [Line Items]
Acquisition-related contingent consideration liabilities, estimated fair value	$ 27,500,000		$ 27,500,000		$ 22,600,000