Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

Reference 1: 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.F)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5047-113901

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

Number of common shares reserved for future issuance related to deferred compensation arrangements with individuals.

+ References

No definition available.

+ Details

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- References

No definition available.

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

+ References

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- References

No definition available.

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- Definition

Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
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- References

No definition available.

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
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Balance Type:	na
Period Type:	duration

- Definition

Number of share instruments newly issued under a share-based compensation plan.

+ References

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

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Period Type:	duration

- Definition

Percentage of vesting of share-based compensation awards.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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- Definition

For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer.

+ References

No definition available.

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Share-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended		6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Total share-based compensation [Abstract]
Total share-based compensation	$ 1,211	$ 2,080	$ 2,561	$ 4,053
Performance share units [Member]
Total share-based compensation [Abstract]
Total share-based compensation	$ 942	1,904	$ 2,020	3,844
Restricted Stock Units [Abstract]
Performance period, equity award			3 years
Common stock shares issued (in shares)			0.2
Common stock shares deferred (in shares)	0.3		0.3
Shares paid for tax withholding (in shares)			0.1
Unrecognized compensation cost [Abstract]
Unrecognized compensation cost related to unvested share awards outstanding	$ 11,700		$ 11,700
Unrecognized compensation cost, expected weighted average period			2 years 11 days
Performance share units [Member] \| Minimum [Member]
Restricted Stock Units [Abstract]
Percentage of target awards to be earned (in hundredths)			0.00%
Performance share units [Member] \| Maximum [Member]
Restricted Stock Units [Abstract]
Percentage of target awards to be earned (in hundredths)			150.00%
Performance share units [Member] \| Performance share units that vest based on TSR [Member]
Restricted Stock Units [Abstract]
Equity awards granted (in shares)			0.2
Equity awards, grant date fair value (in dollars per share)			$ 18.17
Performance share units [Member] \| Performance share units that vest based on Adjusted EPS growth [Member]
Restricted Stock Units [Abstract]
Equity awards granted (in shares)			0.3
Equity awards, grant date fair value (in dollars per share)			$ 15.93
Restricted stock units for board members [Member]
Total share-based compensation [Abstract]
Total share-based compensation	269	$ 176	$ 541	$ 209
Restricted Stock Units [Abstract]
Equity awards granted (in shares)			0.1
Equity awards, grant date fair value (in dollars per share)			$ 15.49
Performance period, equity award			1 year
Unrecognized compensation cost [Abstract]
Unrecognized compensation cost related to unvested share awards outstanding	$ 800		$ 800
Unrecognized compensation cost, expected weighted average period			9 months 28 days