Schedule of Effect of Derivative Instruments in Statement of Operations Recognized (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on foreign currency transactions	$ 3.7	$ 1.4	$ 1.2	$ 2.3

Amount before tax of foreign currency transaction unrealized gain (loss) recognized in the income statement.

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