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Share-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended		6 Months Ended
	Jun. 24, 2020	Jun. 26, 2019	Jun. 24, 2020	Jun. 26, 2019
Total share-based compensation [Abstract]
Total share-based compensation	$ 1,511	$ 2,713	$ (26)	$ 4,966
Certain Employee
Total share-based compensation [Abstract]
Total share-based compensation	1,326	2,463	(420)	4,461
Restricted Stock Units [Abstract]
Unrecognized compensation cost related to unvested share awards outstanding	$ 12,300		$ 12,300
Unrecognized compensation cost, expected weighted average period			1 year 8 months 12 days
Board Members
Restricted Stock Units [Abstract]
Restricted stock units converted into shares of common stock (less than, in shares)	0.1		0.1
Performance share awards | Certain Employee
Restricted Stock Units [Abstract]
Common stock, shares issued (in shares)			0.3
Shares paid for tax withholding (in shares)			0.1
Restricted stock units for board members | Certain Employee
Restricted Stock Units [Abstract]
Grants in periods (less than, in shares)	0.8		0.8
Fair value of units granted (in dollars per share)	$ 10.46		$ 10.46
Award vesting period			2 years
Restricted stock units for board members | Board Members
Total share-based compensation [Abstract]
Total share-based compensation	$ 185	$ 250	$ 394	$ 505
Restricted Stock Units [Abstract]
Grants in periods (less than, in shares)	0.1		0.1
Fair value of units granted (in dollars per share)	$ 10.46		$ 10.46
Unrecognized compensation cost related to unvested share awards outstanding	$ 800		$ 800
Unrecognized compensation cost, expected weighted average period			10 months 24 days
Award vesting period			1 year

X

- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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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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