Stock Based Compensation - Weighted Average Assumptions for Fair Value Stock-Based Awards (Options) (Details)	3 Months Ended	9 Months Ended
Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Weighted average assumptions for fair value estimate of stock-based awards (options)
Average risk free interest rate	1.80%	1.03%	1.79%	1.10%
Expected life (in years)	4 years 6 months 18 days	4 years 6 months 18 days	4 years 6 months 18 days	4 years 6 months 18 days
Average volatility	42.00%	46.00%	42.00%	46.00%

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Weighted average expected volatility rate of share-based compensation awards.

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

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