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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).

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Share-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended		9 Months Ended
	Sep. 25, 2019	Sep. 26, 2018	Sep. 25, 2019	Sep. 26, 2018
Total share-based compensation [Abstract]
Total share-based compensation	$ 2,176	$ 1,100	$ 7,142	$ 3,661
Performance share units [Member]
Total share-based compensation [Abstract]
Total share-based compensation	$ 1,957	902	$ 6,418	2,922
Restricted Stock Units [Abstract]
Performance period, equity award			3 years
Common stock, shares issued			0.4
Common stock, shares deferred	0.4		0.4
Shares paid for tax withholding			0.2
Unrecognized compensation cost [Abstract]
Unrecognized compensation cost related to unvested share awards outstanding	$ 14,300		$ 14,300
Unrecognized compensation cost, expected weighted average period			1 year 10 months 24 days
Performance share units [Member] \| Minimum [Member]
Restricted Stock Units [Abstract]
Percentage of target awards to be earned			0.00%
Performance share units [Member] \| Maximum [Member]
Restricted Stock Units [Abstract]
Percentage of target awards to be earned			150.00%
Performance share units [Member] \| Performance share units that vest based on TSR [Member]
Restricted Stock Units [Abstract]
Equity awards granted (in shares)			0.3
Equity awards, grant date fair value (in dollars per share)			$ 20.47
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)			$ 17.58
Restricted stock units for board members [Member]
Total share-based compensation [Abstract]
Total share-based compensation	219	$ 198	$ 724	$ 739
Restricted Stock Units [Abstract]
Equity awards granted (in shares)			0.1
Equity awards, grant date fair value (in dollars per share)			$ 19.44
Performance period, equity award			1 year
Common stock, shares issued			0.1
Unrecognized compensation cost [Abstract]
Unrecognized compensation cost related to unvested share awards outstanding	$ 500		$ 500
Unrecognized compensation cost, expected weighted average period			7 months 6 days