Date when the acquirer obtains control of the acquiree, in CCYY-MM-DD format.

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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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Name of the acquired entity.

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Total revenue reported by the acquired entity for its previous full fiscal year before the business acquisition.

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Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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Acquisitions Acquisitions Textuals (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Jan. 26, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 875.9	$ 886.8		$ 774.7
Axtone Railway Components Acquisition [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	Jan. 26, 2017
Business Acquisition, Name of Acquired Entity	Axtone Railway Components (Axtone)
Payments to Acquire Businesses, Gross	$ 123.1
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net			$ 123.1
Business Acquisition, Revenue Reported by Acquired Entity for Last Annual Period		$ 72.0
Goodwill			$ 86.0