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COMMITMENTS AND VARIABLE INTEREST ENTITIES - Employee Benefit Plans (Details)	12 Months Ended
	Dec. 27, 2019 USD ($) item	Dec. 28, 2018 USD ($)	Dec. 29, 2017 USD ($)
Number of VIE | item	1
Employee Benefit Plans
Maximum employee contribution as a percentage of compensation under 401 (k) Plan	50.00%
Service period (in months)	3 months
Attained age (in years)	21 years
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	50.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	6.00%
Employer matching contributions	$ 1,996,000	$ 1,120,000	$ 1,021,000
Post-Employment Health Benefits
Unamortized compensation cost	0
Accrued liabilities.
Post-Employment Health Benefits
Present value of expected payments for health insurance coverage	$ 102,000	$ 122,000

X

- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

+ References

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- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

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- Definition

Percentage employer matches of the employee's percentage contribution matched.

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- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

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- References

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- Definition

For a classified balance sheet, the carrying amount as of the balance sheet date of the portion of the obligations recognized for the various benefits provided to former or inactive employees, their beneficiaries, and covered dependents after employment but before retirement that is payable within one year of the balance sheet date.

+ References

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- Definition

Age of employees eligible to participate in defined contribution plan.

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- Definition

Period of services eligible to participate in defined contribution plan.

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- Definition

Represents the information pertaining to number of variable entities.

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- Definition

Represents the unamortized compensation cost related to postemployment benefits.

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