Goodwill and Other Intangible Assets (Change in Goodwill) (Details) $ in Thousands	12 Months Ended
Dec. 31, 2018 USD ($)
Goodwill [Roll Forward]
Balance at December 31, 2017	$ 530,249
Additions related to current year business combinations	18,271
Adjustments related to prior year business combinations	(333)
Effect of foreign currency translation	(2,974)
Balance at December 31, 2018	$ 545,213

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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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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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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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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