Goodwill and Other Intangible Assets Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill, beginning of period	$ 647,077
Goodwill adjustments related to businesses acquired	490
Currency translation effect on foreign goodwill balances	(1,114)
Goodwill, end of period	646,453
Intangible Assets, Net (Excluding Goodwill)	859,961	$ 870,517
Intangible Assets, Net (Including Goodwill)	$ 1,506,414	$ 1,517,594

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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-Name Accounting Standards Codification
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- Definition

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.

+ References

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-Publisher FASB
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- Definition

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.

+ References

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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.

+ References

No definition available.

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- Definition

Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

+ References

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Carrying amount of finite-lived intangible assets, indefinite-lived intangible assets and goodwill. Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Intangible assets are assets, not including financial assets, lacking physical substance.

+ References

No definition available.

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