Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
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-Article 12
-Section 13
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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

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

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The net gain (loss) during the reporting period due to ineffectiveness in interest rate cash flow hedges. Recognized in earnings.

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Financial Instruments - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
Financial Instruments - Narrative (Details) - USD ($)	Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Foreign currency transaction gain (loss) realized	$ 800,000	$ (2,600,000)	$ (5,800,000)	$ (5,400,000)
Hedge ineffectiveness	0	$ 0
Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Notional amount	$ 102,600,000		$ 102,600,000		$ 130,500,000
Foreign currency exchange contracts \| Minimum
Derivatives, Fair Value [Line Items]
Derivative, term of contract (in months)			1 month
Foreign currency exchange contracts \| Maximum
Derivatives, Fair Value [Line Items]
Derivative, term of contract (in months)			3 months
Convertible Debt \| 1.00% Notes
Derivatives, Fair Value [Line Items]
Debt instrument, interest rate (as a percent)	1.00%		1.00%
Convertible Debt \| 1.625% Notes
Derivatives, Fair Value [Line Items]
Debt instrument, interest rate (as a percent)	1.625%		1.625%