Stockholders' Equity Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Accumulated Other Comprehensive Loss, Net of Tax
Balance, beginning of year			$ (46,198)	$ (63,241)
Current-period other comprehensive (loss) income	$ 5,315	$ 9,231	(4,937)	18,225
Balance, end of the period	(51,135)	(45,016)	(51,135)	(45,016)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax		444		1,332
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax		723		2,170
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax		(279)		(838)
Foreign Currency Translation
Accumulated Other Comprehensive Loss, Net of Tax
Balance, beginning of year			(45,149)	(60,299)
Current-period other comprehensive (loss) income			(5,054)	16,797
Balance, end of the period	(50,203)	(43,502)	(50,203)	(43,502)
Cash Flow Hedges
Accumulated Other Comprehensive Loss, Net of Tax
Balance, beginning of year			0	(1,797)
Current-period other comprehensive (loss) income			0	1,332
Balance, end of the period	0	(465)	0	(465)
Pension
Accumulated Other Comprehensive Loss, Net of Tax
Balance, beginning of year			(1,049)	(1,145)
Current-period other comprehensive (loss) income			117	96
Balance, end of the period	$ (932)	$ (1,049)	$ (932)	$ (1,049)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount before tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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Amount after tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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