Schedule of Carrying Amount of Goodwill (Detail) $ in Thousands	6 Months Ended
Jun. 30, 2019 USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill, Beginning Balance	$ 1,019,239
Acquisitions – measurement period adjustments	(13,762)
Goodwill, Ending Balance	1,005,477
Net Book Value, Beginning Balance	1,019,239
Acquisitions – measurement period adjustments	(13,762)
Net Book Value, Ending Balance	$ 1,005,477

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 before 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 (decrease) 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 (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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