Derivative Financial Instruments, Notional Amounts and Fair Values of Foreign Currency Forward Contracts Designated as Cash Flow Hedging Instruments (Details) - Cash Flow Hedging [Member] - Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Oct. 01, 2017
Foreign Exchange Forward [Member]
Derivative [Line Items]
Notional amount of derivative	$ 992,616	$ 1,376,877	$ 1,740,620
Fair value of hedged item	17,434	(7,934)	(11,949)
Inventory Purchases [Member]
Derivative [Line Items]
Notional amount of derivative	555,661	756,673	894,529
Fair value of hedged item	6,827	(13,695)	(16,597)
Sales [Member]
Derivative [Line Items]
Notional amount of derivative	319,421	423,315	579,421
Fair value of hedged item	13,027	16,144	17,215
Royalties and Other [Member]
Derivative [Line Items]
Notional amount of derivative	117,534	196,889	266,670
Fair value of hedged item	$ (2,420)	$ (10,383)	$ (12,567)