Quarterly Financial Information (Unaudited) - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Effect Of Fourth Quarter Events [Line Items]
Income tax benefit related to 2017 Tax Act		$ 1,272.4		$ 1,272.4
Goodwill impairment charge	$ 975.9		$ 975.9	304.7
Product Category Operating Segments [Member] \| Spine [Member]
Effect Of Fourth Quarter Events [Line Items]
Goodwill impairment charge		$ 272.0	$ 401.2	$ 272.0

Amount of loss from the write-down 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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